diff --git a/core-version.txt b/core-version.txt
index 68d92dd..cfaf10a 100644
--- a/core-version.txt
+++ b/core-version.txt
@@ -1 +1 @@
-8.0.6
+8.0.10
diff --git a/package.json b/package.json
index 2dc051b..0555ef8 100644
--- a/package.json
+++ b/package.json
@@ -10,6 +10,8 @@
     "preview": "vite preview",
     "test:ui:accessibility": "node tests/app-shell-accessibility-ui.cjs",
     "test:ui:api-provider-dialog": "node tests/api-provider-dialog-layout-ui.cjs",
+    "test:ui:api-access-layout": "node tests/api-access-layout-ui.cjs",
+    "test:ui:responsive": "node tests/responsive-layout-ui.cjs",
     "screenshots": "node scripts/capture-readme-screenshots.cjs",
     "tauri": "tauri"
   },
diff --git a/src/pages/AgentsPage.tsx b/src/pages/AgentsPage.tsx
index 04bbce9..584e442 100644
--- a/src/pages/AgentsPage.tsx
+++ b/src/pages/AgentsPage.tsx
@@ -2058,7 +2058,7 @@ export function AgentsPage({ embedded = false, onConfigurationApplied }: AgentsP
                   disabled={busy}
                 >
                   <span className="agent-client-icon"><AgentMark definition={agent} /></span>
-                  <span><strong>{agent.name}</strong><small>{listStatusText(status)}</small></span>
+                  <span><strong title={agent.name}>{agent.name}</strong><small title={listStatusText(status)}>{listStatusText(status)}</small></span>
                   {status?.installed ? (
                     <i className="agent-installed-indicator" title={t('agents.clientDetected')} aria-hidden="true" />
                   ) : null}
diff --git a/src/pages/ApiAccessPage.tsx b/src/pages/ApiAccessPage.tsx
index 4837f3e..1280d47 100644
--- a/src/pages/ApiAccessPage.tsx
+++ b/src/pages/ApiAccessPage.tsx
@@ -336,7 +336,7 @@ const rowFromRecord = (
     disabled: grouped ? providerGroupStatus(record) === 'disabled' : definitionFor(section).openAi
       ? readBoolean(record, 'disabled')
       : excludedModels.some((model) => model.trim() === '*'),
-    priority: readNumber(record, 'priority'),
+    priority: record.priority == null ? null : readNumber(record, 'priority'),
     authIndex: entry
       ? readString(entry, 'auth-index', 'authIndex')
       : readString(record, 'auth-index', 'authIndex'),
@@ -1477,6 +1477,7 @@ export function ApiAccessPage() {
               type="button"
               key={definition.id}
               className={definition.id === activeCategory ? 'active' : ''}
+              aria-pressed={definition.id === activeCategory}
               onClick={() => {
                 setActiveCategory(definition.id);
                 feedback.clearNotice();
@@ -1496,6 +1497,10 @@ export function ApiAccessPage() {
               <h2 title={t(activeDefinition.labelKey)}>{t(activeDefinition.labelKey)}</h2>
               <span>{t('apiAccess.groups.summary', { count: rows.length })}</span>
             </div>
+            <div className="management-toolbar compact-toolbar api-access-search">
+              <Search size={16} aria-hidden="true" />
+              <input value={filter} onChange={(event) => setFilter(event.currentTarget.value)} placeholder={t('apiAccess.search')} aria-label={t('apiAccess.search')} />
+            </div>
             <div className="api-access-heading-tools">
               <button type="button" className="secondary-button compact-button" onClick={() => void loadProviders()} disabled={loading || busy}>
                 <RefreshCw size={16} aria-hidden="true" />
@@ -1505,10 +1510,6 @@ export function ApiAccessPage() {
                 <Plus size={16} aria-hidden="true" />
                 {t('apiAccess.groups.add')}
               </button>
-              <div className="management-toolbar compact-toolbar">
-                <Search size={16} aria-hidden="true" />
-                <input value={filter} onChange={(event) => setFilter(event.currentTarget.value)} placeholder={t('apiAccess.search')} />
-              </div>
             </div>
           </div>
 
@@ -1545,21 +1546,20 @@ export function ApiAccessPage() {
                   <div className="provider-row-main">
                     <div className="provider-row-title">
                       <strong title={row.name}>{row.name}</strong>
-                      {row.remark ? <span>{row.remark}</span> : null}
+                      {providerGroupStatus(row.record) === 'partial' ? <span className="state-pill">{t('apiAccess.groups.partial')}</span> : null}
+                      {row.remark ? <span title={row.remark}>{row.remark}</span> : null}
                     </div>
-                    <code title={t('apiAccess.keys.count', { count: row.apiKeys.length })}>
-                      {row.apiKeys.length > 1
-                        ? t('apiAccess.keys.summary', { key: maskSecret(row.apiKey), count: row.apiKeys.length })
-                        : maskSecret(row.apiKey)}
-                    </code>
                     <span className="provider-row-url" title={row.baseUrl || undefined}>{row.baseUrl || t('apiAccess.defaultUrl')}</span>
-                    {row.models.length > 0 ? <span className="provider-row-models">{t('apiAccess.models.summary', { count: row.models.length })}</span> : null}
-                  </div>
-                  {row.priority === null ? null : (
                     <div className="provider-row-meta">
-                      <span>{t('apiAccess.priorityValue', { priority: row.priority })}</span>
+                      <code title={t('apiAccess.keys.count', { count: row.apiKeys.length })}>
+                        {row.apiKeys.length > 1
+                          ? t('apiAccess.keys.summary', { key: maskSecret(row.apiKey), count: row.apiKeys.length })
+                          : maskSecret(row.apiKey)}
+                      </code>
+                      {row.models.length > 0 ? <span className="provider-row-models">{t('apiAccess.models.summary', { count: row.models.length })}</span> : null}
+                      {row.priority === null ? null : <span>{t('apiAccess.priorityValue', { priority: row.priority })}</span>}
                     </div>
-                  )}
+                  </div>
                   <div className="provider-row-actions">
                     <button
                       type="button"
@@ -1582,7 +1582,6 @@ export function ApiAccessPage() {
                         <span className="switch-track" />
                       </span>
                     </label>
-                    {providerGroupStatus(row.record) === 'partial' ? <span className="state-pill">{t('apiAccess.groups.partial')}</span> : null}
                     <button type="button" className="icon-button quiet" onClick={() => openEdit(row)} disabled={busy} title={t('common.edit')} aria-label={t('common.edit')}>
                       <Edit3 size={16} aria-hidden="true" />
                     </button>
diff --git a/src/pages/UsageRecordsPage.tsx b/src/pages/UsageRecordsPage.tsx
index 1883def..8a09203 100644
--- a/src/pages/UsageRecordsPage.tsx
+++ b/src/pages/UsageRecordsPage.tsx
@@ -2616,22 +2616,26 @@ function PricingView({
           </span>
         </div>
         <div className="usage-pricing-actions">
-          <input
-            value={search}
-            onChange={(event) => setSearch(event.currentTarget.value)}
-            placeholder={t('usage.pricing.search')}
-            aria-label={t('usage.pricing.search')}
-          />
-          <button type="button" className="secondary-button" onClick={() => setDraft(emptyPriceDraft())}>
-            {t('usage.pricing.add')}
-          </button>
-          <select value={syncSource} onChange={(event) => changeSyncSource(event.currentTarget.value as 'models-dev' | 'litellm')} aria-label={t('usage.pricing.syncSource')}>
-            <option value="models-dev">Models.dev</option>
-            <option value="litellm">LiteLLM</option>
-          </select>
-          <button type="button" className="primary-button" disabled={syncing} onClick={() => void previewPrices()}>
-            {syncing ? t('usage.pricing.syncing') : t('usage.pricing.sync')}
-          </button>
+          <div className="usage-pricing-action-group">
+            <input
+              value={search}
+              onChange={(event) => setSearch(event.currentTarget.value)}
+              placeholder={t('usage.pricing.search')}
+              aria-label={t('usage.pricing.search')}
+            />
+            <button type="button" className="secondary-button" onClick={() => setDraft(emptyPriceDraft())}>
+              {t('usage.pricing.add')}
+            </button>
+          </div>
+          <div className="usage-pricing-action-group">
+            <select value={syncSource} onChange={(event) => changeSyncSource(event.currentTarget.value as 'models-dev' | 'litellm')} aria-label={t('usage.pricing.syncSource')}>
+              <option value="models-dev">Models.dev</option>
+              <option value="litellm">LiteLLM</option>
+            </select>
+            <button type="button" className="primary-button" disabled={syncing} onClick={() => void previewPrices()}>
+              {syncing ? t('usage.pricing.syncing') : t('usage.pricing.sync')}
+            </button>
+          </div>
         </div>
       </div>
 
@@ -2749,7 +2753,7 @@ function PricingView({
       ) : null}
 
       {visibleRows.length ? (
-        <div className="usage-table-wrap usage-pricing-table-wrap">
+        <div className="usage-table-wrap usage-pricing-table-wrap" tabIndex={0} role="region" aria-label={t('usage.tab.pricing')}>
           <table className="usage-pricing-table">
             <thead>
               <tr>
@@ -2768,7 +2772,7 @@ function PricingView({
               {visibleRows.map((row) => (
                 <tr key={row.model}>
                   <td>
-                    <strong>{row.model}</strong>
+                    <strong title={row.model}>{row.model}</strong>
                   </td>
                   <td>{compactNumber(row.requests)}</td>
                   <td>{compactNumber(row.totalTokens)}</td>
diff --git a/src/styles.css b/src/styles.css
index d2caa55..a249ba0 100644
--- a/src/styles.css
+++ b/src/styles.css
@@ -9787,16 +9787,13 @@ body.table-col-resizing * {
   overflow: auto;
 }
 
-.usage-pricing-panel {
-  min-height: 0;
-  overflow: auto;
-}
-
 /* Pricing Tab */
 .usage-pricing-panel {
-  display: grid;
+  display: flex;
   min-width: 0;
-  align-content: start;
+  min-height: 0;
+  flex-direction: column;
+  overflow: hidden;
   gap: 14px;
   padding: 16px;
   border: 1px solid var(--theme-e3e1db);
@@ -9936,6 +9933,7 @@ body.table-col-resizing * {
 
 .usage-pricing-toolbar {
   display: flex;
+  flex: none;
   align-items: center;
   justify-content: space-between;
   gap: 14px;
@@ -9944,6 +9942,7 @@ body.table-col-resizing * {
 
 .usage-pricing-summary {
   display: grid;
+  flex: 1 1 240px;
   gap: 2px;
 }
 
@@ -9961,13 +9960,26 @@ body.table-col-resizing * {
 
 .usage-pricing-actions {
   display: flex;
+  min-width: 0;
+  flex: 1 1 560px;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 8px;
+}
+
+.usage-pricing-action-group {
+  display: flex;
+  min-width: 0;
+  flex: 1 1 250px;
   align-items: center;
   gap: 8px;
 }
 
 .usage-pricing-actions input,
 .usage-pricing-actions select {
-  min-width: 180px;
+  width: 100%;
+  min-width: 0;
+  flex: 1 1 0;
   height: 34px;
   padding: 0 10px;
   border: 1px solid var(--theme-d5d2cb);
@@ -9979,7 +9991,10 @@ body.table-col-resizing * {
 
 .usage-pricing-actions button,
 .usage-price-editor-actions button {
+  flex: none;
+  min-height: 34px;
   height: 34px;
+  white-space: nowrap;
 }
 
 .usage-price-sync-dialog {
@@ -10035,6 +10050,10 @@ body.table-col-resizing * {
 
 .usage-price-editor {
   display: grid;
+  min-height: 0;
+  flex: 0 1 auto;
+  max-height: 50%;
+  overflow: auto;
   grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
   gap: 10px;
   padding: 14px;
@@ -10073,13 +10092,26 @@ body.table-col-resizing * {
 }
 
 .usage-pricing-table-wrap {
-  min-height: 380px;
+  min-height: 120px;
+}
+
+.usage-pricing-table-wrap::-webkit-scrollbar,
+.usage-pricing-table-wrap::-webkit-scrollbar:horizontal {
+  display: block;
+  width: 8px;
+  height: 8px;
+}
+
+.usage-pricing-table-wrap::-webkit-scrollbar-thumb {
+  border-radius: 4px;
+  background: var(--border-primary);
 }
 
 .usage-pricing-table {
   width: 100%;
   min-width: 980px;
-  border-collapse: collapse;
+  border-collapse: separate;
+  border-spacing: 0;
   font-size: var(--font-size-meta);
 }
 
@@ -10105,7 +10137,22 @@ body.table-col-resizing * {
 
 .usage-pricing-table th:first-child,
 .usage-pricing-table td:first-child {
-  text-align: center;
+  position: sticky;
+  left: 0;
+  min-width: 180px;
+  max-width: 240px;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  box-shadow: 1px 0 0 var(--border-color);
+}
+
+.usage-pricing-table td:first-child {
+  z-index: 1;
+  background: var(--bg-primary);
+}
+
+.usage-pricing-table th:first-child {
+  z-index: 2;
 }
 
 .usage-price-row-actions {
@@ -11271,24 +11318,6 @@ body.table-col-resizing * {
     grid-template-columns: 1fr;
   }
 
-  .usage-pricing-toolbar {
-    align-items: stretch;
-    flex-direction: column;
-  }
-
-  .usage-pricing-actions {
-    display: grid;
-    grid-template-columns: 1fr;
-  }
-
-  .usage-pricing-actions input {
-    width: 100%;
-  }
-
-  .usage-price-editor {
-    grid-template-columns: 1fr;
-  }
-
   .thinking-alias-workbench {
     grid-template-columns: 1fr;
   }
diff --git a/src/styles/feature-pages.css b/src/styles/feature-pages.css
index 3cea88d..1b4f4b0 100644
--- a/src/styles/feature-pages.css
+++ b/src/styles/feature-pages.css
@@ -2976,11 +2976,6 @@
     grid-template-columns: 1fr;
   }
 
-  .usage-topbar {
-    align-items: stretch;
-    flex-direction: column;
-  }
-
   .usage-tabs {
     display: flex;
     width: 100%;
@@ -2996,42 +2991,16 @@
     padding-inline: 12px;
   }
 
-  .usage-topbar-actions {
-    width: 100%;
-  }
-
   .usage-events-summary-left,
   .usage-events-summary-right {
     width: 100%;
     justify-content: space-between;
   }
 
-  .usage-collector-state {
-    flex: 1;
-  }
-
   .usage-analysis-grid {
     grid-template-columns: 1fr;
   }
 
-  .usage-pricing-toolbar {
-    align-items: stretch;
-    flex-direction: column;
-  }
-
-  .usage-pricing-actions {
-    display: grid;
-    grid-template-columns: 1fr;
-  }
-
-  .usage-pricing-actions input {
-    width: 100%;
-  }
-
-  .usage-price-editor {
-    grid-template-columns: 1fr;
-  }
-
   .auth-files-toolbar {
     grid-template-columns: 18px minmax(0, 1fr);
   }
diff --git a/src/styles/index.css b/src/styles/index.css
index 66ada7b..d6a3448 100644
--- a/src/styles/index.css
+++ b/src/styles/index.css
@@ -1,3 +1,7 @@
 @import '../styles.css';
 @import './feature-pages.css';
 @import './ui-refinements.css';
+@import './responsive-shell-usage.css';
+@import './responsive-providers.css';
+@import './responsive-agents.css';
+@import './responsive-settings.css';
diff --git a/src/styles/responsive-agents.css b/src/styles/responsive-agents.css
new file mode 100644
index 0000000..05f5c89
--- /dev/null
+++ b/src/styles/responsive-agents.css
@@ -0,0 +1,244 @@
+/* Use the space left for the workbench, including the app sidebar and padding. */
+.agents-page:not(.agents-page-embedded) {
+  container: agent-workspace / inline-size;
+}
+
+@container agent-workspace (max-width: 760px) {
+  .app-shell:has(.agents-page:not(.agents-page-embedded)) .agent-workbench {
+    grid-template-columns: minmax(0, 1fr);
+    grid-template-rows: auto minmax(0, 1fr);
+    gap: 12px;
+  }
+
+  .app-shell:has(.agents-page:not(.agents-page-embedded)) .agent-client-list {
+    height: auto;
+    max-height: none;
+    gap: 6px;
+    padding: 10px 12px;
+  }
+
+  .agents-page:not(.agents-page-embedded) .agent-list-items {
+    display: grid;
+    flex: none;
+    grid-auto-flow: column;
+    grid-auto-columns: 192px;
+    grid-template-columns: none;
+    grid-template-rows: auto;
+    overflow-x: auto;
+    overflow-y: hidden;
+    padding: 0 0 4px;
+    scrollbar-gutter: auto;
+    scroll-snap-type: x proximity;
+  }
+
+  .agents-page:not(.agents-page-embedded) .agent-list-items button {
+    min-height: 58px;
+    scroll-snap-align: start;
+  }
+
+  .agents-page:not(.agents-page-embedded) .agent-list-items strong,
+  .agents-page:not(.agents-page-embedded) .agent-list-items small {
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+  }
+}
+
+.agent-save-bar,
+.agent-codex-save-actions,
+.agent-signin-label,
+.agent-section-heading-actions {
+  flex-wrap: wrap;
+}
+
+.agent-save-bar .agent-save-feedback {
+  flex-basis: 180px;
+}
+
+.agent-save-actions button,
+.agent-management-actions button {
+  max-width: 100%;
+}
+
+.agent-section-heading > div:first-child,
+.agent-claude-code-disable-compact > span:first-child {
+  overflow-wrap: anywhere;
+}
+
+@container agent-panel (max-width: 640px) {
+  .agent-desktop-models > .agent-section-heading {
+    align-items: flex-start;
+    flex-direction: column;
+  }
+
+  .agent-desktop-models > .agent-section-heading > .agent-section-heading-actions {
+    width: 100%;
+    justify-content: flex-start;
+  }
+
+  .agent-desktop-model-fields {
+    grid-template-columns: minmax(0, 1fr) auto;
+    gap: 8px;
+  }
+
+  .agent-desktop-model-field:first-child {
+    grid-column: 1 / -1;
+  }
+
+  .agent-desktop-model-actions {
+    height: 44px;
+    justify-self: end;
+  }
+
+  .agent-status-grid,
+  .agent-status-grid.dual-install-status-grid,
+  .agent-status-grid.pi-status-grid {
+    grid-template-columns: repeat(auto-fit, minmax(min(100%, 140px), 1fr));
+  }
+
+  .codex-session-overview-head,
+  .codex-session-list-head {
+    flex-wrap: wrap;
+    align-items: flex-start;
+  }
+
+  .codex-session-selection-actions {
+    justify-content: flex-start;
+  }
+
+  .codex-session-pagination {
+    flex-wrap: wrap;
+  }
+}
+
+@container agent-panel (max-width: 420px) {
+  .agent-subpage-tabs {
+    width: fit-content;
+    overflow-x: auto;
+  }
+
+  .agent-subpage-tabs button {
+    flex: none;
+    width: auto;
+    padding-inline: 10px;
+  }
+
+  .agent-signin-explanation dl > div {
+    grid-template-columns: minmax(0, 1fr);
+    gap: 4px;
+  }
+
+  .codex-session-meta,
+  .codex-session-row:has(.codex-session-checkbox) .codex-session-meta {
+    grid-template-columns: auto minmax(0, 1fr);
+    gap: 6px;
+  }
+
+  .codex-session-meta time {
+    grid-column: 1 / -1;
+    justify-self: start;
+  }
+}
+
+/* Catalog forms must respond to the editor width, not the whole dialog. */
+.codex-catalog-editor {
+  container: catalog-editor / inline-size;
+}
+
+.codex-catalog-sidebar,
+.codex-catalog-form > label,
+.codex-catalog-models > button {
+  min-width: 0;
+}
+
+.codex-catalog-model-heading,
+.codex-catalog-footer,
+.codex-catalog-footer > div:last-child,
+.codex-catalog-confirm > div > div {
+  flex-wrap: wrap;
+}
+
+.codex-catalog-model-heading > button {
+  flex: none;
+  max-width: 100%;
+}
+
+.codex-catalog-footer > div:last-child {
+  margin-left: auto;
+}
+
+.codex-catalog-hint,
+.codex-catalog-heading p {
+  overflow-wrap: anywhere;
+}
+
+@container catalog-editor (max-width: 500px) {
+  .codex-catalog-form,
+  .harness-reasoning-levels {
+    grid-template-columns: minmax(0, 1fr);
+  }
+}
+
+/* Keep the model list beside the editor on small desktop windows so it does
+   not consume most of the dialog's available height. */
+@media (min-width: 600px) and (max-width: 900px) {
+  .codex-catalog-body,
+  .harness-catalog-dialog .codex-catalog-body {
+    grid-template-columns: 180px minmax(0, 1fr);
+    grid-template-rows: minmax(0, 1fr);
+  }
+
+  .codex-catalog-sidebar {
+    grid-template-columns: minmax(0, 1fr);
+    grid-template-rows: auto minmax(0, 1fr) auto;
+    gap: 8px;
+    padding: 10px;
+    border-right: 1px solid var(--theme-d5d2cb);
+    border-bottom: 0;
+  }
+
+  .harness-catalog-dialog .codex-catalog-sidebar {
+    grid-template-rows: auto auto minmax(0, 1fr) auto;
+  }
+
+  .codex-catalog-sidebar > *,
+  .harness-catalog-dialog .codex-catalog-sidebar > * {
+    grid-column: 1;
+    grid-row: auto;
+  }
+
+  .codex-catalog-footer {
+    flex-direction: row;
+    gap: 8px;
+  }
+
+  .codex-catalog-footer > div:last-child {
+    display: flex;
+  }
+}
+
+.agent-backup-modal {
+  container: agent-backup / inline-size;
+}
+
+.agent-backup-modal footer {
+  flex-wrap: wrap;
+}
+
+.agent-backup-columns nav {
+  min-width: 0;
+}
+
+.agent-backup-columns nav button {
+  overflow-wrap: anywhere;
+}
+
+@container agent-backup (max-width: 680px) {
+  .agent-backup-columns {
+    grid-template-columns: minmax(0, 1fr);
+  }
+
+  .agent-backup-columns nav {
+    max-height: 160px;
+  }
+}
diff --git a/src/styles/responsive-providers.css b/src/styles/responsive-providers.css
new file mode 100644
index 0000000..6f4bc0c
--- /dev/null
+++ b/src/styles/responsive-providers.css
@@ -0,0 +1,435 @@
+/* Keep API navigation above the list at every width. */
+.api-access-page .real-provider-workbench {
+  grid-template-columns: minmax(0, 1fr);
+  gap: 16px;
+}
+
+.api-access-page .provider-category-panel {
+  display: grid;
+  grid-template-columns: repeat(5, minmax(0, 1fr));
+  gap: 4px;
+  height: auto;
+  padding: 8px;
+}
+
+.api-access-page .provider-category-panel button {
+  grid-template-columns: 24px minmax(0, auto) auto;
+  justify-content: center;
+  gap: 8px;
+  height: 50px;
+  min-height: 50px;
+  padding: 8px;
+  border-radius: 8px;
+}
+
+.api-access-page .provider-category-panel button.active {
+  background: var(--ui-accent-soft);
+  border-color: color-mix(in srgb, var(--ui-accent) 20%, transparent);
+  color: var(--ui-accent);
+}
+
+.api-access-page .provider-category-panel .provider-logo {
+  width: 24px;
+  height: 24px;
+}
+
+.api-access-page .provider-category-panel span {
+  white-space: normal;
+  overflow-wrap: normal;
+  overflow: hidden;
+  text-overflow: clip;
+}
+
+.api-access-page .provider-category-panel strong {
+  justify-self: center;
+  min-width: 22px;
+  padding: 2px 5px;
+  border-radius: 6px;
+  background: var(--bg-secondary);
+  color: var(--text-quaternary);
+  font-size: 12px;
+  line-height: 18px;
+  text-align: center;
+}
+
+.api-access-page .provider-category-panel .active strong {
+  background: color-mix(in srgb, var(--ui-accent) 10%, var(--bg-primary));
+  color: var(--ui-accent);
+}
+
+.api-access-page .provider-resource-panel {
+  container: provider-resources / inline-size;
+  min-width: 0;
+  min-height: 0;
+}
+
+.api-access-page .management-panel-heading {
+  display: grid;
+  grid-template-columns: auto minmax(180px, 1fr) auto;
+  grid-template-areas: 'title search actions';
+  gap: 14px 24px;
+  align-items: center;
+}
+
+.api-access-page .management-panel-heading > div:first-child {
+  grid-area: title;
+  text-align: left;
+}
+
+.api-access-page .api-access-search {
+  grid-area: search;
+  width: 100%;
+  max-width: 440px;
+  justify-self: end;
+}
+
+.api-access-page .api-access-heading-tools {
+  grid-area: actions;
+  display: flex;
+  width: auto;
+  flex: none;
+  flex-wrap: wrap;
+  align-items: center;
+  justify-content: flex-end;
+  gap: 8px;
+}
+
+.api-access-page .api-access-heading-tools > button {
+  flex: 0 0 auto;
+  width: auto;
+}
+
+.api-access-page .real-provider-list {
+  margin-top: 18px;
+}
+
+.api-access-page .real-provider-row {
+  grid-template-columns: 24px minmax(0, 1fr) auto;
+  align-items: center;
+  gap: 12px;
+  min-height: 104px;
+  padding: 16px 0;
+}
+
+.api-access-page .real-provider-row:last-child {
+  border-bottom: 0;
+  padding-bottom: 0;
+}
+
+.api-access-page .provider-drag-handle {
+  grid-column: 1;
+  grid-row: 1;
+  width: 24px;
+  min-width: 24px;
+  height: 32px;
+  padding: 0;
+  margin: 0;
+  align-self: start;
+  border-color: transparent;
+  background: transparent;
+  box-shadow: none;
+}
+
+.api-access-page .provider-row-main {
+  grid-column: 2;
+  grid-row: 1;
+  gap: 7px;
+}
+
+.api-access-page .provider-row-title {
+  align-items: baseline;
+  flex-wrap: wrap;
+  gap: 2px 10px;
+}
+
+.api-access-page .provider-row-title strong {
+  max-width: 100%;
+  font-size: 15px;
+  line-height: 22px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.api-access-page .provider-row-title > span:not(.state-pill) {
+  min-width: 0;
+  max-width: 100%;
+  overflow: hidden;
+  color: var(--text-quaternary);
+  font-size: 12px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.api-access-page .provider-row-title .state-pill {
+  min-height: 22px;
+  padding: 1px 7px;
+  font-size: 11px;
+  line-height: 18px;
+}
+
+.api-access-page .provider-row-main > .provider-row-url {
+  overflow: hidden;
+  font-size: 13px;
+  line-height: 20px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.api-access-page .provider-row-meta {
+  display: flex;
+  flex-direction: row;
+  flex-wrap: wrap;
+  justify-content: flex-start;
+  align-items: center;
+  gap: 6px 12px;
+  padding: 0;
+  line-height: 20px;
+}
+
+.api-access-page .provider-row-meta code {
+  min-width: 0;
+  max-width: 100%;
+  overflow-wrap: anywhere;
+  color: var(--text-quaternary);
+  font-size: 12px;
+}
+
+.api-access-page .provider-row-meta span {
+  flex: none;
+  color: var(--text-quaternary);
+  font-size: 12px;
+}
+
+.api-access-page .provider-row-actions {
+  grid-column: 3;
+  grid-row: 1;
+  flex-wrap: wrap;
+  justify-content: flex-end;
+  gap: 8px;
+  max-width: 340px;
+}
+
+.api-access-page .provider-enabled-control {
+  min-width: 0;
+}
+
+.api-access-page .provider-row-actions .icon-button {
+  width: 32px;
+  height: 32px;
+  min-width: 32px;
+}
+
+/* Compact tabs keep every category visible instead of wrapping a lone tab. */
+@container workspace (max-width: 820px) {
+  .api-access-page .provider-category-panel button {
+    grid-template-columns: 24px auto;
+    grid-template-rows: 24px auto;
+    gap: 4px 8px;
+    height: auto;
+    min-height: 68px;
+  }
+
+  .api-access-page .provider-category-panel span {
+    grid-column: 1 / -1;
+    grid-row: 2;
+    font-size: 12px;
+    text-align: center;
+    white-space: normal;
+    overflow-wrap: normal;
+  }
+
+  .api-access-page .provider-category-panel strong {
+    grid-column: 2;
+    grid-row: 1;
+  }
+}
+
+@container provider-resources (max-width: 720px) {
+  .api-access-page .management-panel-heading {
+    grid-template-columns: minmax(0, 1fr) auto;
+    grid-template-areas: 'title actions' 'search search';
+    column-gap: 12px;
+  }
+
+  .api-access-page .api-access-search {
+    max-width: none;
+  }
+}
+
+@container provider-resources (max-width: 580px) {
+  .api-access-page .real-provider-row {
+    grid-template-columns: 24px minmax(0, 1fr);
+    gap: 10px;
+  }
+
+  .api-access-page .provider-row-actions {
+    grid-column: 2;
+    grid-row: 2;
+    max-width: none;
+    justify-content: flex-start;
+  }
+}
+
+/* Keep controls compact while allowing complete groups to move to the next line. */
+.auth-files-page .management-heading-actions {
+  min-width: 0;
+  max-width: 100%;
+  flex-wrap: wrap;
+}
+
+.auth-files-page .management-heading-actions button {
+  flex: 0 0 auto;
+  width: auto;
+}
+
+.auth-files-page .real-auth-files-panel {
+  container: credential-files / inline-size;
+  min-width: 0;
+}
+
+.auth-files-page .auth-files-toolbar select {
+  min-width: 0;
+}
+
+@container credential-files (max-width: 680px) {
+  .auth-files-page .auth-files-toolbar {
+    grid-template-columns: 18px minmax(0, 1fr) minmax(0, 1fr);
+    gap: 0 9px;
+  }
+
+  .auth-files-page .auth-files-toolbar input {
+    grid-column: 2 / -1;
+  }
+
+  .auth-files-page .auth-files-toolbar select:first-of-type {
+    grid-column: 1 / 3;
+  }
+
+  .auth-files-page .auth-files-toolbar select:last-of-type {
+    grid-column: 3;
+  }
+
+  .auth-files-page .auth-files-toolbar select {
+    border-top: 1px solid var(--theme-e3e1db);
+    border-left: 0;
+  }
+}
+
+.oauth-login-page > .oauth-grid {
+  grid-template-columns: repeat(auto-fit, minmax(min(360px, 100%), 1fr));
+}
+
+.oauth-browser-picker {
+  min-width: 0;
+  max-width: 100%;
+  flex-wrap: wrap;
+}
+
+.oauth-browser-picker select {
+  min-width: 0;
+  max-width: 100%;
+  flex: 0 1 240px;
+}
+
+.oauth-card .oauth-auth-url-actions,
+.oauth-card .management-card-actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px;
+}
+
+.oauth-card .management-card-actions > button {
+  flex: 1 1 auto;
+}
+
+.oauth-card .oauth-callback-row {
+  grid-template-columns: minmax(0, 1fr) auto;
+}
+
+.oauth-card .oauth-callback-row > button {
+  width: auto;
+  white-space: nowrap;
+}
+
+.quota-group-heading {
+  flex-wrap: wrap;
+}
+
+.quota-group-heading .quota-group-actions {
+  flex: 1 1 280px;
+}
+
+.quota-group-actions .muted-summary {
+  width: auto;
+}
+
+.real-quota-row > div:first-child {
+  flex-wrap: wrap;
+}
+
+.real-quota-row small,
+.quota-reset-credit-summary span {
+  min-width: 0;
+  white-space: normal;
+  overflow-wrap: anywhere;
+}
+
+/* Optional key selectors must not shift fixed dialog grid tracks onto the model list. */
+.model-discovery-dialog.provider-health-dialog {
+  display: flex;
+  flex-direction: column;
+  height: min(660px, calc(100dvh - 48px));
+  min-height: 0;
+  overflow: auto;
+}
+
+.provider-health-dialog > :not(.provider-health-model-list) {
+  flex-shrink: 0;
+}
+
+.provider-health-dialog .provider-health-model-list {
+  flex: 1 1 180px;
+  min-height: 100px;
+  height: auto;
+}
+
+.provider-health-dialog .model-discovery-header > div {
+  flex-wrap: wrap;
+}
+
+.provider-health-dialog .model-discovery-header span {
+  white-space: normal;
+  overflow-wrap: anywhere;
+}
+
+.provider-health-dialog .provider-health-key-selector {
+  min-width: 0;
+  padding: 0;
+}
+
+.model-discovery-dialog .model-discovery-toolbar,
+.model-discovery-dialog .model-discovery-actions,
+.model-discovery-dialog .model-transfer-summary {
+  flex-wrap: wrap;
+}
+
+.model-discovery-dialog .model-discovery-toolbar > span {
+  white-space: normal;
+}
+
+.api-provider-dialog .provider-group-heading,
+.api-provider-dialog .model-config-heading,
+.api-provider-dialog .thinking-level-heading {
+  flex-wrap: wrap;
+}
+
+@container workspace (max-width: 760px) {
+  .oauth-browser-picker {
+    justify-content: flex-start;
+  }
+
+  .auth-files-page .management-heading-actions,
+  .quota-group-heading .quota-group-actions {
+    justify-content: flex-start;
+  }
+}
diff --git a/src/styles/responsive-settings.css b/src/styles/responsive-settings.css
new file mode 100644
index 0000000..416b59d
--- /dev/null
+++ b/src/styles/responsive-settings.css
@@ -0,0 +1,342 @@
+/* Keep each section responsive to its available content width, including the
+   sidebar and the narrower cards in the two-column home layout. */
+.home-quick-actions {
+  grid-template-columns: repeat(4, minmax(0, 1fr));
+}
+
+@container workspace (max-width: 1080px) {
+  .home-quick-actions {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+  }
+}
+
+@container workspace (max-width: 480px) {
+  .home-quick-actions {
+    grid-template-columns: minmax(0, 1fr);
+  }
+}
+
+.client-api-panel {
+  container: home-api / inline-size;
+}
+
+.client-api-panel .client-api-heading {
+  flex-wrap: wrap;
+  gap: 10px;
+}
+
+.client-api-panel .client-api-heading > div {
+  flex: 1 1 260px;
+}
+
+.client-api-panel .client-api-key-actions {
+  max-width: 100%;
+  flex-shrink: 1;
+}
+
+.client-api-key-code {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+@container home-api (max-width: 480px) {
+  .client-api-card {
+    height: auto;
+    flex-direction: column;
+    align-items: stretch;
+    gap: 10px;
+  }
+
+  .client-api-card-heading {
+    flex: none;
+    width: auto;
+    min-width: 0;
+  }
+}
+
+/* The download source is one control group: move the group together, then let
+   the select shrink while the action retains a readable label. */
+.version-management-page > .version-list {
+  padding: 0;
+}
+
+.version-source-row {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 16px 24px;
+}
+
+.version-source-copy {
+  flex: 1 1 240px;
+}
+
+.version-source-control {
+  grid-template-columns: minmax(0, 1fr) auto;
+  width: min(360px, 100%);
+  min-width: 0;
+}
+
+.version-source-control label,
+.version-source-control select {
+  min-width: 0;
+  width: 100%;
+}
+
+.version-source-add-button {
+  grid-column: auto;
+  white-space: nowrap;
+}
+
+@container workspace (max-width: 620px) {
+  .app-release-notes-heading {
+    flex-wrap: wrap;
+    padding: 16px;
+  }
+
+  .app-release-notes-body {
+    padding: 0 16px 16px;
+  }
+
+  .app-release-notes-markdown {
+    gap: 14px 12px;
+  }
+
+  .app-release-notes-markdown > .release-notes-category {
+    max-width: 80px;
+  }
+}
+
+/* Settings have variable-length descriptions; fixed row heights and controls
+   sized from the window instead of the workspace can make adjacent cards overlap. */
+.config-page .config-panel-heading,
+.config-page .config-heading-actions,
+.config-page .config-network-section-heading,
+.config-page .config-proxy-heading {
+  flex-wrap: wrap;
+}
+
+.config-page .config-panel-heading {
+  gap: 10px 14px;
+}
+
+.config-page .config-heading-actions {
+  margin-left: auto;
+}
+
+.config-keys-panel {
+  grid-template-rows: auto minmax(0, 1fr);
+}
+
+.config-network-grid {
+  grid-auto-rows: minmax(154px, auto);
+}
+
+.config-network-field small,
+.config-diagnostics-setting-copy,
+.config-software-setting-copy {
+  overflow-wrap: anywhere;
+}
+
+.config-diagnostics-actions,
+.config-management-actions {
+  flex-wrap: wrap;
+}
+
+@container workspace (max-width: 900px) {
+  .config-network-grid {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+  }
+
+  .config-diagnostics-toggle-grid {
+    grid-template-columns: minmax(0, 1fr);
+  }
+}
+
+@container workspace (max-width: 700px) {
+  .config-diagnostics-fields {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+  }
+
+  .config-software-setting-row {
+    gap: 16px;
+    padding: 15px 16px;
+  }
+
+  .config-software-close-row {
+    align-items: stretch;
+    flex-direction: column;
+  }
+
+  .config-software-select {
+    width: 100%;
+    min-width: 0;
+    padding-left: 54px;
+  }
+
+  .config-diagnostics-footer,
+  .config-management-form-footer {
+    grid-template-columns: minmax(0, 1fr);
+    gap: 8px;
+  }
+
+  .config-diagnostics-actions {
+    justify-content: flex-end;
+  }
+}
+
+@container workspace (max-width: 560px) {
+  .config-network-grid,
+  .config-diagnostics-fields {
+    grid-template-columns: minmax(0, 1fr);
+  }
+
+  .config-network-grid {
+    grid-auto-rows: auto;
+  }
+
+  .config-software-select {
+    padding-left: 0;
+  }
+
+  .config-heading-title h2 {
+    white-space: normal;
+  }
+}
+
+/* Alias routes should keep their names readable before metadata and actions
+   wrap onto a second line. The editor uses its own width inside a modal. */
+.thinking-alias-list-panel {
+  container: alias-list / inline-size;
+}
+
+.thinking-alias-dialog {
+  container: alias-editor / inline-size;
+}
+
+.thinking-alias-field {
+  min-width: 0;
+}
+
+@container alias-list (max-width: 560px) {
+  .thinking-alias-row {
+    grid-template-columns: minmax(0, 1fr) 34px;
+  }
+
+  .thinking-alias-route {
+    grid-column: 1 / -1;
+  }
+
+  .thinking-alias-badges {
+    flex-wrap: wrap;
+    justify-content: flex-start;
+  }
+}
+
+@container alias-editor (max-width: 580px) {
+  .thinking-effort-options {
+    grid-template-columns: repeat(4, minmax(0, 1fr));
+  }
+}
+
+/* Keep novice-mode actions compact at intermediate widths. Existing phone
+   rules made every action full-width even when two controls easily fit. */
+.simple-mode-topbar,
+.simple-mode-topbar-right,
+.simple-mode-brand-title,
+.simple-mode-choice-title,
+.simple-mode-api-model-heading,
+.simple-mode-api-model-selection-heading {
+  flex-wrap: wrap;
+}
+
+.simple-mode-topbar-left,
+.simple-mode-topbar-right,
+.simple-mode-brand,
+.simple-mode-brand-text {
+  min-width: 0;
+}
+
+.simple-mode-topbar-left {
+  flex: 1 1 340px;
+}
+
+.simple-mode-topbar-right {
+  flex: 0 1 auto;
+  justify-content: flex-end;
+  margin-left: auto;
+}
+
+.simple-mode-topbar-right > *,
+.simple-mode-guide-toggle {
+  flex-shrink: 0;
+}
+
+.simple-mode-choice-title strong,
+.simple-mode-brand-title strong {
+  white-space: normal;
+  overflow-wrap: anywhere;
+}
+
+.simple-mode-provider-card-foot {
+  flex-wrap: wrap;
+}
+
+.simple-mode-field .text-input,
+.simple-mode-field .select-input {
+  min-width: 0;
+}
+
+@container workspace (max-width: 720px) {
+  .simple-mode-topbar-left,
+  .simple-mode-topbar-right {
+    width: 100%;
+  }
+
+  .simple-mode-topbar-right {
+    justify-content: flex-start;
+  }
+
+  .simple-mode-choice-grid,
+  .simple-mode-api-fields {
+    grid-template-columns: minmax(0, 1fr);
+  }
+
+  .simple-mode-api-actions,
+  .simple-mode-task-footer {
+    display: flex;
+    flex-direction: row;
+    align-items: center;
+    flex-wrap: wrap;
+  }
+
+  .simple-mode-api-actions button,
+  .simple-mode-task-footer > .primary-button,
+  .simple-mode-task-footer > .secondary-button {
+    width: auto;
+  }
+
+  .simple-mode-task-footer > .primary-button {
+    margin-left: auto;
+  }
+}
+
+@container workspace (max-width: 520px) {
+  .simple-mode-api-model-options {
+    grid-template-columns: minmax(0, 1fr);
+  }
+
+  .simple-mode-step-status-track {
+    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
+  }
+
+  .simple-mode-step-status-connector {
+    display: none;
+  }
+
+  .simple-mode-step-status-copy strong,
+  .simple-mode-step-status-copy small {
+    white-space: normal;
+    overflow-wrap: anywhere;
+  }
+}
diff --git a/src/styles/responsive-shell-usage.css b/src/styles/responsive-shell-usage.css
new file mode 100644
index 0000000..ddc9eeb
--- /dev/null
+++ b/src/styles/responsive-shell-usage.css
@@ -0,0 +1,174 @@
+/* Keep footer controls reachable when desktop navigation exceeds the height. */
+@media (min-width: 901px) {
+  .sidebar-brand,
+  .sidebar-bottom {
+    flex-shrink: 0;
+  }
+
+  .sidebar > .nav-section {
+    min-height: 0;
+    margin-bottom: 18px;
+    overflow-x: hidden;
+    overflow-y: auto;
+    scrollbar-width: thin;
+  }
+}
+
+/* Let toolbar rows keep their height instead of overlapping the table. */
+.usage-events-summary {
+  flex: none;
+  flex-wrap: wrap;
+}
+
+.usage-events-summary-left,
+.usage-events-summary-right {
+  width: auto;
+  max-width: 100%;
+  justify-content: flex-start;
+}
+
+.usage-events-summary-right {
+  margin-left: auto;
+}
+
+.usage-pagination-controls {
+  min-width: 0;
+  max-width: 100%;
+  flex-wrap: wrap;
+}
+
+.usage-topbar,
+.usage-filter-panel {
+  flex-shrink: 0;
+}
+
+.usage-page-navigation,
+.usage-topbar-actions {
+  max-width: 100%;
+}
+
+.usage-tabs,
+.config-subpage-tabs,
+.oauth-subpage-tabs {
+  min-width: 0;
+  max-width: 100%;
+  overflow-x: auto;
+}
+
+.usage-tabs button,
+.config-subpage-tabs button,
+.oauth-subpage-tabs button {
+  flex-shrink: 0;
+  white-space: nowrap;
+}
+
+.usage-topbar-actions {
+  min-width: 0;
+  flex-wrap: wrap;
+}
+
+.usage-collector-state {
+  max-width: 100%;
+}
+
+.usage-collector-state > span:last-child {
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.usage-section-heading {
+  gap: 10px;
+  flex-wrap: wrap;
+}
+
+.usage-section-heading > div {
+  min-width: 0;
+}
+
+.usage-section-heading strong {
+  white-space: normal;
+  overflow-wrap: anywhere;
+}
+
+.usage-custom-range input {
+  min-width: 0;
+  max-width: 100%;
+}
+
+.usage-pricing-table-wrap:focus-visible {
+  outline: 2px solid var(--ui-accent);
+  outline-offset: -2px;
+}
+
+.usage-pricing-panel {
+  overflow: auto;
+}
+
+.usage-price-editor {
+  min-height: 160px;
+  max-height: min(320px, 40vh);
+  flex-shrink: 0;
+}
+
+.usage-storage-limit-editor {
+  min-width: 0;
+  max-width: 100%;
+}
+
+.usage-storage-limit-editor label {
+  min-width: 0;
+  flex: 1;
+}
+
+.usage-storage-limit-editor input {
+  min-width: 0;
+  width: 100%;
+  max-width: 168px;
+}
+
+.usage-storage-limit-editor button {
+  flex: none;
+  white-space: nowrap;
+}
+
+@container workspace (max-width: 760px) {
+  .usage-overview-layout {
+    grid-template-columns: minmax(0, 1fr);
+    grid-template-rows: max-content minmax(280px, 1fr) auto;
+  }
+
+  .usage-health-panel {
+    height: auto;
+  }
+
+  .usage-data-management-action {
+    flex-wrap: wrap;
+    gap: 12px;
+  }
+
+  .usage-data-management-action > div:first-child {
+    min-width: 0;
+    flex: 1 1 260px;
+  }
+}
+
+@container workspace (max-width: 540px) {
+  .usage-events-summary-right {
+    margin-left: 0;
+  }
+
+  .usage-storage-limit-editor {
+    flex-direction: row;
+  }
+
+  .usage-storage-limit-editor .primary-button {
+    width: auto;
+  }
+}
+
+@media (min-width: 761px) {
+  .usage-events-panel > .usage-table-wrap,
+  .usage-events-panel > .usage-empty {
+    min-height: 0;
+  }
+}
diff --git a/src/styles/ui-refinements.css b/src/styles/ui-refinements.css
index 7d3fe54..357f065 100644
--- a/src/styles/ui-refinements.css
+++ b/src/styles/ui-refinements.css
@@ -387,40 +387,6 @@ body, html, #root {
   font-weight: var(--font-weight-semibold);
 }
 
-/* API access toolbar */
-.api-access-page .management-panel-heading {
-  align-items: center;
-  flex-wrap: wrap;
-}
-
-.api-access-heading-tools {
-  display: flex;
-  min-width: 0;
-  flex: 1 1 420px;
-  align-items: center;
-  justify-content: flex-end;
-  gap: 8px;
-}
-
-.api-access-heading-tools .compact-toolbar {
-  width: min(280px, 100%);
-  flex: 1 1 180px;
-}
-
-
-@container workspace (max-width: 760px) {
-  .api-access-heading-tools {
-    width: 100%;
-    flex-basis: 100%;
-    flex-wrap: wrap;
-    justify-content: flex-start;
-  }
-
-  .api-access-heading-tools .compact-toolbar {
-    flex-basis: 100%;
-  }
-}
-
 /* 7. OAuth Management Page Polish */
 .oauth-management-page .management-header h1 {
   display: none;
@@ -618,13 +584,18 @@ body, html, #root {
   gap: 8px;
 }
 
+.usage-records-page .usage-filter-group {
+  display: grid;
+  min-width: 0;
+  grid-template-columns: repeat(6, minmax(0, 1fr));
+}
+
 .usage-records-page .usage-filter-item {
   flex: 1 1 150px;
   flex-direction: row;
   align-items: center;
   gap: 0;
-  min-width: 132px;
-  max-width: 210px;
+  min-width: 0;
   height: 36px;
   padding: 0 8px;
   border: 1px solid var(--border-color);
@@ -688,6 +659,18 @@ body, html, #root {
   color: var(--text-primary);
 }
 
+@container workspace (max-width: 880px) {
+  .usage-records-page .usage-filter-group {
+    grid-template-columns: repeat(3, minmax(0, 1fr));
+  }
+}
+
+@container workspace (max-width: 520px) {
+  .usage-records-page .usage-filter-group {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+  }
+}
+
 .usage-records-page .usage-section-heading strong {
   color: #1d1d1f;
   font-weight: 650;
diff --git a/tests/agent-configuration-layout-ui.cjs b/tests/agent-configuration-layout-ui.cjs
index f8869bb..97bdaea 100644
--- a/tests/agent-configuration-layout-ui.cjs
+++ b/tests/agent-configuration-layout-ui.cjs
@@ -128,27 +128,42 @@ const desktopViewports = [
     const assertClientListScroll = async (label, { requireOverflow = true } = {}) => {
       const metrics = await page.locator('.agent-list-items').evaluate(list => {
         const style = getComputedStyle(list);
-        const last = list.lastElementChild;
-        list.scrollTop = list.scrollHeight;
-        const scrollTop = list.scrollTop;
+        const overflowX = list.scrollWidth > list.clientWidth + 1;
+        const overflowY = list.scrollHeight > list.clientHeight + 1;
+        const original = {
+          left: list.scrollLeft,
+          top: list.scrollTop,
+          snap: list.style.scrollSnapType,
+          behavior: list.style.scrollBehavior,
+        };
+        list.style.scrollSnapType = 'none';
+        list.style.scrollBehavior = 'auto';
         const listRect = list.getBoundingClientRect();
-        const lastRect = last?.getBoundingClientRect();
-        const lastReachable = !!lastRect && lastRect.top >= listRect.top - 1 && lastRect.bottom <= listRect.bottom + 1;
-        list.scrollTop = 0;
+        const unreachable = Array.from(list.querySelectorAll('button')).filter(button => {
+          const before = button.getBoundingClientRect();
+          list.scrollLeft += before.left - listRect.left;
+          list.scrollTop += before.top - listRect.top;
+          const after = button.getBoundingClientRect();
+          return after.left < listRect.left - 1 || after.right > listRect.right + 1
+            || after.top < listRect.top - 1 || after.bottom > listRect.bottom + 1;
+        }).map(button => button.textContent.trim());
+        const scrollable = (!overflowX || ['auto', 'scroll'].includes(style.overflowX))
+          && (!overflowY || ['auto', 'scroll'].includes(style.overflowY));
+        list.scrollLeft = original.left;
+        list.scrollTop = original.top;
+        list.style.scrollSnapType = original.snap;
+        list.style.scrollBehavior = original.behavior;
         return {
-          clientHeight: list.clientHeight,
-          scrollHeight: list.scrollHeight,
-          overflowY: style.overflowY,
-          scrollTop,
-          lastReachable,
+          overflows: overflowX || overflowY,
+          scrollable,
+          unreachable,
         };
       });
-      assert.equal(metrics.overflowY, 'auto', `${label}: the client list must own vertical scrolling`);
+      assert.equal(metrics.scrollable, true, `${label}: overflowing client options must remain scrollable`);
       if (requireOverflow) {
-        assert.ok(metrics.scrollHeight > metrics.clientHeight + 1, `${label}: the complete client list must overflow internally`);
-        assert.ok(metrics.scrollTop > 0, `${label}: the client list must accept scrolling`);
+        assert.equal(metrics.overflows, true, `${label}: the fixture must exercise scrolling through the client list`);
       }
-      assert.equal(metrics.lastReachable, true, `${label}: scrolling must reveal the final client`);
+      assert.deepEqual(metrics.unreachable, [], `${label}: scrolling must reveal every client option`);
     };
 
     const assertDesktopLayout = async (label, { requireClientOverflow = true } = {}) => {
@@ -421,6 +436,8 @@ const desktopViewports = [
     `${shellNarrowLabel}: panels must stack at the same width after the workspace breakpoint`);
     assert.ok(shellNarrow.client.bottom <= shellNarrow.configuration.y + 1,
       `${shellNarrowLabel}: the client list must remain above the configuration panel`);
+    assert.ok(shellNarrow.configuration.height >= shellNarrow.workbench.height / 2,
+      `${shellNarrowLabel}: stacked client options must leave most of the workbench available for configuration`);
     assert.ok(Math.abs(shellNarrow.bottomGap - shellNarrow.paddingBottom) <= 1,
       `${shellNarrowLabel}: the stacked workbench must preserve the fixed window-edge gap`);
     assert.ok(shellNarrow.documentScrollHeight <= shellNarrow.documentClientHeight + 1,
diff --git a/tests/api-access-layout-ui.cjs b/tests/api-access-layout-ui.cjs
new file mode 100644
index 0000000..318e488
--- /dev/null
+++ b/tests/api-access-layout-ui.cjs
@@ -0,0 +1,138 @@
+const { chromium } = require(process.env.PLAYWRIGHT_MODULE || 'playwright');
+const assert = require('node:assert/strict');
+const path = require('node:path');
+
+const widths = [1440, 980, 854, 640];
+const locales = ['zh-CN', 'en'];
+
+(async () => {
+  const { createServer } = await import('vite');
+  const react = (await import('@vitejs/plugin-react')).default;
+  const server = await createServer({
+    configFile: false,
+    root: path.resolve(__dirname, '..'),
+    plugins: [react()],
+    optimizeDeps: { entries: ['tests/fixtures/provider-groups.html'] },
+    logLevel: 'error',
+    server: { host: '127.0.0.1', port: 0, watch: null },
+  });
+  let browser;
+  try {
+    await server.listen();
+    const base = `http://127.0.0.1:${server.httpServer.address().port}`;
+    const channel = process.env.PLAYWRIGHT_CHANNEL || (process.platform === 'win32' ? 'msedge' : undefined);
+    browser = await chromium.launch({ channel, headless: true, args: ['--no-proxy-server'] });
+    const errors = [];
+
+    for (const locale of locales) for (const width of widths) {
+      const label = `${locale} ${width}x600`;
+      const page = await browser.newPage({ viewport: { width, height: 600 } });
+      page.setDefaultTimeout(10000);
+      page.on('pageerror', error => errors.push(`${label}: ${error}`));
+      await page.route('**/*', route => route.request().url().startsWith(`${base}/`) ? route.continue() : route.abort());
+      await page.goto(`${base}/tests/fixtures/provider-groups.html?layout=dense&locale=${locale}`, { waitUntil: 'domcontentloaded' });
+      await page.waitForFunction(() => document.querySelectorAll('.real-provider-row').length === 4
+        && document.querySelectorAll('.provider-row-title > span:not(.state-pill)').length === 4);
+      await page.evaluate(async () => {
+        await document.fonts.ready;
+        await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+      });
+
+      const navigation = await page.locator('.provider-category-panel').evaluate(panel => {
+        const rect = panel.getBoundingClientRect();
+        const buttons = [...panel.querySelectorAll('button')];
+        return {
+          count: buttons.length,
+          rows: new Set(buttons.map(button => Math.round(button.getBoundingClientRect().top))).size,
+          allVisible: buttons.every(button => {
+            const item = button.getBoundingClientRect();
+            return item.width > 0 && item.height > 0 && item.left >= rect.left - 1 && item.right <= rect.right + 1
+              && item.top >= rect.top - 1 && item.bottom <= rect.bottom + 1 && item.right <= innerWidth + 1;
+          }),
+          labelsFit: buttons.every(button => {
+            const label = button.querySelector('span');
+            const range = document.createRange();
+            range.selectNodeContents(label);
+            const text = range.getBoundingClientRect();
+            const bounds = label.getBoundingClientRect();
+            return text.left >= bounds.left - 1 && text.right <= bounds.right + 1
+              && text.top >= bounds.top - 1 && text.bottom <= bounds.bottom + 1;
+          }),
+          bottom: rect.bottom,
+          listTop: document.querySelector('.provider-resource-panel').getBoundingClientRect().top,
+        };
+      });
+      assert.equal(navigation.count, 5, `${label}: every provider category remains available`);
+      assert.equal(navigation.rows, 1, `${label}: categories retain a single top row`);
+      assert.equal(navigation.allVisible, true, `${label}: all category controls fit without hidden columns`);
+      assert.equal(navigation.labelsFit, true, `${label}: full category names stay readable`);
+      assert.ok(navigation.bottom <= navigation.listTop + 1, `${label}: category navigation stays above the resource list`);
+
+      const overflow = await page.evaluate(() => [document.documentElement, document.body,
+        document.querySelector('.content'), document.querySelector('.api-access-page')]
+        .filter(element => element.scrollWidth > element.clientWidth + 1)
+        .map(element => element.className || element.tagName));
+      assert.deepEqual(overflow, [], `${label}: dense API content must not overflow the page horizontally`);
+
+      const groups = await page.evaluate(() => window.groupFixture.groups);
+      const rows = page.locator('.real-provider-row');
+      for (const group of groups) {
+        const row = rows.filter({ has: page.locator('.provider-row-title strong', { hasText: group.name }) });
+        const meta = row.locator('.provider-row-meta');
+        assert.equal(await row.count(), 1, `${label}: each group has exactly one row`);
+        assert.equal(await meta.isVisible(), true, `${label} ${group.name}: metadata stays visible`);
+        const metaText = await meta.innerText();
+        const expectedModels = locale === 'en' ? `${group.models.length} models` : `模型 ${group.models.length} 个`;
+        if (group.models.length) assert.ok(metaText.includes(expectedModels), `${label} ${group.name}: model count is preserved`);
+        const priorityLabel = locale === 'en' ? 'Priority' : '优先级';
+        if (group.priority === null) assert.ok(!metaText.includes(priorityLabel), `${label}: inherited priority is not displayed as zero`);
+        else assert.ok(metaText.includes(`${priorityLabel} ${group.priority}`), `${label} ${group.name}: priority, including zero, is preserved`);
+        if (group.keys.length > 1) {
+          const keyCount = locale === 'en' ? `${group.keys.length} keys total` : `共 ${group.keys.length} 个密钥`;
+          assert.ok(metaText.includes(keyCount), `${label} ${group.name}: multiple keys stay grouped and counted`);
+        }
+        assert.equal(await row.locator('.provider-row-url').getAttribute('title'), group['base-url'], `${label}: full URL remains available`);
+        const remark = row.locator('.provider-row-title > span:not(.state-pill)');
+        assert.equal(await remark.getAttribute('title'), await remark.textContent(), `${label}: the full remark remains available when shortened`);
+
+        const layout = await row.evaluate(element => {
+          const bounds = element.getBoundingClientRect();
+          const main = element.querySelector('.provider-row-main').getBoundingClientRect();
+          const actions = element.querySelector('.provider-row-actions').getBoundingClientRect();
+          const controls = [...element.querySelectorAll('.provider-row-actions > button, .provider-enabled-control')];
+          const rects = controls.map(control => control.getBoundingClientRect());
+          const overlap = (a, b) => Math.min(a.right, b.right) - Math.max(a.left, b.left) > 1
+            && Math.min(a.bottom, b.bottom) - Math.max(a.top, b.top) > 1;
+          return {
+            mainOverlapsActions: overlap(main, actions),
+            controlsContained: rects.every(rect => rect.width > 0 && rect.height > 0 && rect.left >= bounds.left - 1
+              && rect.right <= bounds.right + 1 && rect.top >= bounds.top - 1 && rect.bottom <= bounds.bottom + 1),
+            controlsOverlap: rects.some((rect, index) => rects.slice(index + 1).some(next => overlap(rect, next))),
+          };
+        });
+        assert.equal(layout.mainOverlapsActions, false, `${label} ${group.name}: details and actions do not overlap`);
+        assert.equal(layout.controlsContained, true, `${label} ${group.name}: every action fits its own row`);
+        assert.equal(layout.controlsOverlap, false, `${label} ${group.name}: action targets remain separate`);
+        for (const control of await row.locator('.provider-row-actions > button, .provider-enabled-control, .provider-drag-handle').all()) {
+          await control.scrollIntoViewIfNeeded();
+          assert.equal(await control.evaluate(element => {
+            const rect = element.getBoundingClientRect();
+            const hit = document.elementFromPoint(rect.left + rect.width / 2, rect.top + rect.height / 2);
+            return rect.top >= -1 && rect.bottom <= innerHeight + 1 && !!hit && element.contains(hit);
+          }), true, `${label} ${group.name}: actions and drag handle remain reachable by scrolling`);
+        }
+      }
+
+      const partial = rows.filter({ hasText: 'Mock Borealis partial' });
+      assert.equal(await partial.locator('.state-pill').textContent(), locale === 'en' ? 'Some keys disabled' : '部分密钥已停用');
+      assert.equal(await rows.filter({ hasText: 'Mock Dusk disabled' }).getByRole('checkbox').isChecked(), false);
+      assert.deepEqual(await page.evaluate(() => window.groupFixture.writes), [], 'Layout checks must not change provider records');
+      await page.close();
+    }
+    assert.deepEqual(errors, [], 'Dense API layouts must not produce runtime errors');
+    console.log('PASS: dense API groups retain navigation, metadata and reachable actions at four widths in Chinese and English.');
+  } finally {
+    if (browser) await browser.close();
+    await server.close();
+  }
+})().catch(error => { console.error(error); process.exitCode = 1; });
diff --git a/tests/fixtures/provider-groups.tsx b/tests/fixtures/provider-groups.tsx
index 4f18746..1ab476f 100644
--- a/tests/fixtures/provider-groups.tsx
+++ b/tests/fixtures/provider-groups.tsx
@@ -2,22 +2,71 @@ import React from 'react';
 import { createRoot } from 'react-dom/client';
 import { mockIPC } from '@tauri-apps/api/mocks';
 import { I18nProvider } from '../../src/i18n';
-import { ApiAccessPage } from '../../src/pages/ApiAccessPage';
+import {
+  ApiAccessPage,
+  apiAccessRemarkLocatorFromRecord,
+  providerRemarkIdentity,
+  type ApiAccessRemarkLocator,
+  type ProviderSection,
+} from '../../src/pages/ApiAccessPage';
 import '../../src/styles/index.css';
 
-localStorage.setItem('easy-cli-proxy-api.locale', new URLSearchParams(location.search).get('locale') ?? 'en');
+const query = new URLSearchParams(location.search);
+const denseLayout = query.get('layout') === 'dense';
+localStorage.setItem('easy-cli-proxy-api.locale', query.get('locale') ?? 'en');
 const fixture = window as typeof window & { groupFixture: { groups: Record<string, unknown>[], writes: unknown[], probes: unknown[] } };
 fixture.groupFixture = {
-  groups: [{ name: 'Primary gateway', 'base-url': 'https://gateway.example.test/v1', priority: 2,
+  groups: denseLayout ? [
+    {
+      name: 'Mock Atlas primary', 'base-url': 'https://atlas.example.test/v1', priority: 10,
+      models: [{ name: 'mock-codex-large' }, { name: 'mock-codex-small' }, { name: 'mock-codex-fast' }],
+      keys: [{ 'api-key': 'mock-atlas-key-one' }, { 'api-key': 'mock-atlas-key-two' }, { 'api-key': 'mock-atlas-key-three' }],
+    },
+    {
+      name: 'Mock Borealis partial',
+      'base-url': 'https://borealis-layout-only.example.test/a-deliberately-long-routing-path/organization-fictional-team/workspace-for-responsive-layout-verification/openai-compatible/v1',
+      priority: 0, models: [{ name: 'mock-codex-reasoning' }, { name: 'mock-codex-compact' }],
+      keys: [{ 'api-key': 'mock-borealis-active' }, { 'api-key': 'mock-borealis-paused', 'excluded-models': ['*'] }],
+    },
+    {
+      name: 'Mock Cirrus gateway with a deliberately long fictional group name',
+      'base-url': 'https://cirrus.example.test/v1', priority: null,
+      models: [{ name: 'mock-codex-standard' }], keys: [{ 'api-key': 'mock-cirrus-only-key' }],
+    },
+    {
+      name: 'Mock Dusk disabled', 'base-url': 'https://dusk.example.test/v1', priority: 5,
+      'excluded-models': ['*'], models: [],
+      keys: [{ 'api-key': 'mock-dusk-key-one' }, { 'api-key': 'mock-dusk-key-two' }],
+    },
+  ] : [{ name: 'Primary gateway', 'base-url': 'https://gateway.example.test/v1', priority: 2,
     headers: { 'X-Group': 'shared' }, models: [{ name: 'gpt-original' }, { name: 'gpt-original', alias: 'gpt-fast' }],
     keys: [{ 'api-key': 'key-inherited', weight: 2, priority: null },
       { 'api-key': 'key-overridden', weight: 5, priority: 0, 'proxy-url': 'direct', headers: { 'X-Key': 'second' }, models: [{ name: 'private-model' }], 'excluded-models': [], 'disable-cooling': false }],
   }, { name: 'Backup gateway', 'base-url': 'https://backup.example.test/v1', models: [{ name: 'backup-model' }], keys: [{ 'api-key': 'backup-key' }] }],
   writes: [], probes: [],
 };
+const denseRemarks = [
+  'Fictional layout fixture · 三个测试密钥',
+  'One fictional key paused · 用于检查部分启用状态',
+  '仅用于响应式布局测试的虚构备注：故意保留很长的说明，验证窄窗口中的名称、备注、URL、密钥数量和操作仍然清楚。 Fictional layout-only remark with enough text to exercise wrapping and truncation without real credentials or services.',
+  'Disabled fictional group · 无已配置模型',
+];
+const remarks = new Map<string, string>();
+if (denseLayout) fixture.groupFixture.groups.forEach((group, index) => {
+  remarks.set(providerRemarkIdentity('codex-api-key', apiAccessRemarkLocatorFromRecord('codex-api-key', group)), denseRemarks[index]);
+});
 mockIPC((cmd, args: any) => {
-  if (cmd === 'set_app_locale' || cmd === 'save_api_access_remark') return null;
-  if (cmd === 'resolve_api_access_remarks') return args.queries.map(() => '');
+  if (cmd === 'set_app_locale') return null;
+  if (cmd === 'resolve_api_access_remarks') return args.queries.map((item: ApiAccessRemarkLocator & { providerSection: ProviderSection }) =>
+    denseLayout ? remarks.get(providerRemarkIdentity(item.providerSection, item)) ?? '' : '');
+  if (cmd === 'save_api_access_remark') {
+    if (denseLayout) {
+      const update = args.update as { providerSection: ProviderSection; previousRecords: ApiAccessRemarkLocator[]; records: ApiAccessRemarkLocator[]; remark: string };
+      update.previousRecords.forEach(record => remarks.delete(providerRemarkIdentity(update.providerSection, record)));
+      update.records.forEach(record => remarks.set(providerRemarkIdentity(update.providerSection, record), update.remark));
+    }
+    return null;
+  }
   if (cmd !== 'management_request') throw new Error(`Unexpected ${cmd}`);
   const request = args.request;
   if (request.path === '/requests/api-call') {
diff --git a/tests/responsive-layout-ui.cjs b/tests/responsive-layout-ui.cjs
new file mode 100644
index 0000000..4c324e1
--- /dev/null
+++ b/tests/responsive-layout-ui.cjs
@@ -0,0 +1,256 @@
+const { chromium } = require(process.env.PLAYWRIGHT_MODULE || 'playwright');
+const assert = require('node:assert/strict');
+const path = require('node:path');
+
+const viewports = [
+  { width: 640, height: 600 },
+  { width: 800, height: 600 },
+  { width: 964, height: 600 },
+  { width: 1280, height: 800 },
+];
+
+(async () => {
+  let server;
+  let browser;
+  let base = 'http://127.0.0.1:1420/';
+  try {
+    try {
+      const response = await fetch(base, { signal: AbortSignal.timeout(3000) });
+      if (!response.ok) throw new Error(String(response.status));
+    } catch {
+      const { createServer } = await import('vite');
+      const react = (await import('@vitejs/plugin-react')).default;
+      server = await createServer({
+        configFile: false,
+        root: path.resolve(__dirname, '..'),
+        plugins: [react()],
+        logLevel: 'error',
+        server: { host: '127.0.0.1', port: 1421, strictPort: false },
+      });
+      await server.listen();
+      base = `http://127.0.0.1:${server.httpServer.address().port}/`;
+    }
+
+    const channel = process.env.PLAYWRIGHT_CHANNEL || (process.platform === 'win32' ? 'msedge' : undefined);
+    browser = await chromium.launch({ channel, headless: true, args: ['--no-proxy-server'] });
+    let page;
+    const errors = [];
+
+    const settle = () => page.evaluate(async () => {
+      await document.fonts.ready;
+      await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+    });
+    const open = async (label, ready) => {
+      await page.locator('.nav-section button').filter({ has: page.getByText(label, { exact: true }) }).click();
+      await page.locator(ready).first().waitFor();
+      await settle();
+    };
+    const tab = async (id, ready) => {
+      await page.locator(`#${id}`).click();
+      await page.locator(ready).first().waitFor();
+      await settle();
+    };
+    const assertNoPageOverflow = async label => {
+      const overflow = await page.evaluate(() => {
+        const nodes = [document.documentElement, document.body,
+          document.querySelector('.content'), document.querySelector('.content > .page')].filter(Boolean);
+        return nodes.filter(node => node.scrollWidth > node.clientWidth + 1)
+          .map(node => ({ element: node.className || node.tagName, client: node.clientWidth, scroll: node.scrollWidth }));
+      });
+      assert.deepEqual(overflow, [], `${label}: horizontal scrolling must stay inside intentional tables or navigation`);
+    };
+    const assertReachable = async (locator, label) => {
+      await locator.scrollIntoViewIfNeeded();
+      assert.equal(await locator.evaluate(element => {
+        const rect = element.getBoundingClientRect();
+        if (rect.width <= 0 || rect.height <= 0 || rect.left < -1 || rect.right > innerWidth + 1
+          || rect.top < -1 || rect.bottom > innerHeight + 1) return false;
+        const hit = document.elementFromPoint(rect.left + rect.width / 2, rect.top + rect.height / 2);
+        return !!hit && element.contains(hit);
+      }), true, `${label}: the control must be visible and unobstructed after scrolling`);
+    };
+    const assertRequestToolbar = async label => {
+      const metrics = await page.locator('.usage-events-panel').evaluate(panel => {
+        const summary = panel.querySelector('.usage-events-summary');
+        const scrollbar = panel.querySelector('.usage-table-top-scrollbar');
+        const pagination = panel.querySelector('.usage-pagination-controls');
+        const summaryRect = summary.getBoundingClientRect();
+        const scrollbarRect = scrollbar.getBoundingClientRect();
+        const paginationRect = pagination.getBoundingClientRect();
+        const controls = [...pagination.querySelectorAll('button, select, .usage-pagination-info')];
+        return {
+          summaryBottom: summaryRect.bottom,
+          scrollbarTop: scrollbarRect.top,
+          controlsContained: controls.every(control => {
+            const rect = control.getBoundingClientRect();
+            return rect.width > 0 && rect.height > 0
+              && rect.left >= paginationRect.left - 1 && rect.right <= paginationRect.right + 1
+              && rect.top >= paginationRect.top - 1 && rect.bottom <= paginationRect.bottom + 1
+              && rect.bottom <= summaryRect.bottom + 1;
+          }),
+        };
+      });
+      assert.ok(metrics.summaryBottom <= metrics.scrollbarTop + 1, `${label}: request summary must not overlap the horizontal scrollbar`);
+      assert.equal(metrics.controlsContained, true, `${label}: pagination controls must fit completely inside their toolbar`);
+      for (const control of await page.locator('.usage-pagination-controls button, .usage-page-size-select').all()) {
+        await assertReachable(control, `${label} pagination`);
+      }
+      const scrolled = await page.locator('.usage-events-panel .usage-table-wrap').evaluate(table => {
+        table.scrollLeft = table.scrollWidth;
+        return { overflowing: table.scrollWidth > table.clientWidth, scrolled: table.scrollLeft > 0 };
+      });
+      assert.equal(scrolled.overflowing, true, `${label}: the full request table remains available beyond the viewport`);
+      assert.equal(scrolled.scrolled, true, `${label}: request columns remain reachable by horizontal scrolling`);
+    };
+    const assertExpandedPricing = async () => {
+      await page.getByRole('combobox', { name: '时间范围', exact: true }).selectOption('custom');
+      await page.locator('.usage-custom-range').waitFor();
+      await page.getByRole('button', { name: '手动添加', exact: true }).click();
+      const editor = page.locator('.usage-price-editor');
+      await editor.waitFor();
+      await settle();
+      // A clipped ancestor can be scrolled programmatically by scrollIntoView,
+      // while still preventing the user from reaching the overflowing content.
+      const clipped = await page.locator('.usage-pricing-table-wrap').evaluate(table => {
+        const ancestors = [];
+        for (let parent = table.parentElement; parent; parent = parent.parentElement) {
+          if (['hidden', 'clip'].includes(getComputedStyle(parent).overflowY)
+            && parent.scrollHeight > parent.clientHeight + 1) ancestors.push(parent.className);
+        }
+        return ancestors;
+      });
+      assert.deepEqual(clipped, [], 'Expanded pricing content must remain reachable through user scrolling');
+      await assertReachable(editor.getByRole('button', { name: '保存', exact: true }), '800x600 price editor save');
+      await assertReachable(editor.getByRole('button', { name: '取消', exact: true }), '800x600 price editor cancel');
+      const table = page.locator('.usage-pricing-table-wrap');
+      await assertReachable(table, '800x600 price table');
+      const scrollbarReachable = await table.evaluate(element => {
+        const rect = element.getBoundingClientRect();
+        const y = rect.bottom - 2;
+        if (y < 0 || y >= innerHeight) return false;
+        const hit = document.elementFromPoint(rect.left + rect.width / 2, y);
+        if (!hit || !element.contains(hit)) return false;
+        for (let parent = element.parentElement; parent; parent = parent.parentElement) {
+          if (getComputedStyle(parent).overflowY !== 'visible') {
+            const bounds = parent.getBoundingClientRect();
+            if (y < bounds.top || y > bounds.bottom) return false;
+          }
+        }
+        element.scrollLeft = element.scrollWidth;
+        return element.scrollLeft > 0;
+      });
+      assert.equal(scrollbarReachable, true, 'Expanded pricing table scrollbar must remain visible and usable');
+      await editor.getByRole('button', { name: '取消', exact: true }).click();
+      await editor.waitFor({ state: 'detached' });
+    };
+
+    for (const viewport of viewports) {
+      const label = `${viewport.width}x${viewport.height}`;
+      // browser.newPage creates an isolated context, so persisted tabs, selected
+      // clients and table preferences cannot leak between viewport cases.
+      page = await browser.newPage({ viewport });
+      page.setDefaultTimeout(10000);
+      page.on('pageerror', error => errors.push(`${label}: ${error}`));
+      await page.route('**/*', route => route.request().url().startsWith(base) ? route.continue() : route.abort());
+      await page.addInitScript(() => localStorage.setItem('easy-cli-proxy-api.locale', 'zh-CN'));
+      await page.goto(`${base}?mock=running`, { waitUntil: 'domcontentloaded' });
+      await page.locator('.home-page .client-api-card').first().waitFor();
+      // The native app does not include the development scenario picker overlay.
+      await page.addStyleTag({ content: '#browser-mock-toolbar { display: none; }' });
+      await settle();
+      await assertNoPageOverflow(`${label} home`);
+
+      if (viewport.width === 964) {
+        assert.equal(await page.locator('.sidebar-bottom').evaluate(footer => {
+          const rect = footer.getBoundingClientRect();
+          return rect.top >= 0 && rect.bottom <= innerHeight + 1;
+        }), true, `${label}: desktop sidebar footer must stay visible without scrolling the page`);
+        await assertReachable(page.locator('.sidebar-contact'), `${label} sidebar contact`);
+      }
+
+      await open('API 接入', '.real-provider-row');
+      await assertNoPageOverflow(`${label} API access`);
+      if (viewport.width === 964) {
+        const rows = await page.locator('.provider-category-panel button').evaluateAll(buttons =>
+          new Set(buttons.map(button => Math.round(button.getBoundingClientRect().top))).size);
+        assert.equal(rows, 1, `${label}: provider navigation must not consume several rows in a short window`);
+        await assertReachable(page.locator('.provider-category-panel button').last(), `${label} final provider category`);
+      }
+      await assertReachable(page.locator('.provider-row-actions button').first(), `${label} provider action`);
+
+      await open('OAuth', '.oauth-subpage-tabs');
+      await tab('oauth-subpage-tab-login', '.oauth-card');
+      await assertNoPageOverflow(`${label} OAuth login`);
+      await tab('oauth-subpage-tab-authFiles', '.auth-file-card');
+      await assertNoPageOverflow(`${label} OAuth credentials`);
+      await tab('oauth-subpage-tab-quota', '.real-quota-card');
+      await assertNoPageOverflow(`${label} OAuth quota`);
+
+      await open('智能体配置', '.agent-config-panel');
+      await page.waitForFunction(() => !document.querySelector('.agent-client-list-heading button')?.disabled);
+      await tab('agent-subpage-tab-core', '#agent-subpage-panel-core');
+      await assertNoPageOverflow(`${label} agents`);
+      const configuration = page.locator('#agent-subpage-panel-core');
+      assert.equal(await configuration.evaluate(element => {
+        const rect = element.getBoundingClientRect();
+        return rect.width > 0 && rect.height > 0;
+      }), true, `${label}: the configuration area must not collapse below its tab bar`);
+      const agentControl = configuration.locator('button, input:not([type="hidden"]), select').filter({ visible: true }).first();
+      await assertReachable(agentControl, `${label} agent configuration`);
+
+      await open('使用记录', '.usage-tabs');
+      await tab('usage-tab-overview', '.usage-overview-layout');
+      await assertNoPageOverflow(`${label} usage overview`);
+      for (const [id, ready] of [
+        ['analysis', '.usage-analysis-grid'],
+        ['events', '.usage-events-table tbody tr'],
+        ['pricing', '.usage-pricing-table-wrap tbody tr'],
+        ['data-management', '.usage-data-management-panel'],
+      ]) {
+        await tab(`usage-tab-${id}`, ready);
+        await assertNoPageOverflow(`${label} usage ${id}`);
+        if (id === 'events') await assertRequestToolbar(label);
+        if (id === 'pricing' && viewport.width === 800) await assertExpandedPricing();
+      }
+
+      await open('高级功能', '#config-subpage-panel');
+      for (const id of ['general', 'network', 'routing', 'aliases', 'software', 'sensitive-words']) {
+        await tab(`config-subpage-tab-${id}`, `#config-subpage-panel[aria-labelledby="config-subpage-tab-${id}"]`);
+        await assertNoPageOverflow(`${label} settings ${id}`);
+      }
+
+      await open('版本管理', '.version-list-item');
+      await assertNoPageOverflow(`${label} versions`);
+      await page.close();
+    }
+
+    page = await browser.newPage({ viewport: { width: 640, height: 600 } });
+    page.setDefaultTimeout(10000);
+    page.on('pageerror', error => errors.push(`640x600 English: ${error}`));
+    await page.route('**/*', route => route.request().url().startsWith(base) ? route.continue() : route.abort());
+    await page.addInitScript(() => localStorage.setItem('easy-cli-proxy-api.locale', 'en'));
+    await page.goto(`${base}?mock=running`, { waitUntil: 'domcontentloaded' });
+    await page.locator('.home-page').waitFor();
+    await page.addStyleTag({ content: '#browser-mock-toolbar { display: none; }' });
+    await open('Advanced Features', '.config-subpage-tabs');
+    for (const id of ['general', 'network', 'routing', 'aliases', 'software', 'sensitive-words']) {
+      await tab(`config-subpage-tab-${id}`, `#config-subpage-panel[aria-labelledby="config-subpage-tab-${id}"]`);
+      await assertNoPageOverflow(`640x600 English settings ${id}`);
+      const button = page.locator(`#config-subpage-tab-${id}`);
+      await assertReachable(button, `English settings ${id} tab`);
+      assert.equal(await button.evaluate(element => {
+        const range = document.createRange();
+        range.selectNodeContents(element);
+        const text = range.getBoundingClientRect();
+        const bounds = element.getBoundingClientRect();
+        return text.left >= bounds.left - 1 && text.right <= bounds.right + 1;
+      }), true, `English ${id} label must fit inside its own clickable tab`);
+    }
+    await page.close();
+    assert.deepEqual(errors, [], 'Responsive navigation must not produce runtime errors');
+    console.log('PASS: responsive pages, short-window navigation, reachable controls, and independent request-table scrolling.');
+  } finally {
+    if (browser) await browser.close();
+    if (server) await server.close();
+  }
+})().catch(error => { console.error(error); process.exitCode = 1; });