diff --git a/docs/plugin-development.md b/docs/plugin-development.md
index 9e3909f7..063fab87 100644
--- a/docs/plugin-development.md
+++ b/docs/plugin-development.md
@@ -25,6 +25,18 @@ Rust 模板还包含编译脚本，编译后自动填入当前平台的可执行
 将生成的 `.nyap` 安装到插件面板，检查权限并启用。UI 模板需先选中已连接终端；
 Rust 模板可以打开界面点击运行，也可以直接执行插件卡片上的原生命令。
 
+## 页面字体
+
+宿主会将应用的界面字体栈通过 `NyaTerm.context.theme` 中的 `--font-sans`、
+`--font-display` 同步到插件页面；修改设置时，已打开的页面也会收到更新，无需重载。
+`--font-mono` 提供宿主的默认等宽字体栈。SDK 默认使用界面字体，表单控件继承字体；
+插件自定义 CSS 应使用 `font-family: var(--font-sans, system-ui, sans-serif)`，
+代码区域可使用 `var(--font-mono, monospace)`，避免写死 `system-ui`。
+
+iframe 可以使用系统安装的字体，但不会继承主界面的 `@font-face`。
+若使用未安装到系统的内置字体或其他 Web 字体，需要在插件包内提供字体文件并声明
+`@font-face`。已有插件若写死字体，需要修改 CSS 并重新打包安装。
+
 ## 编写 Rust 后台
 
 入口实现 `Plugin`，由 `Server::from_env()` 启动服务。SDK 负责握手、传输、
diff --git a/docs/plugins.md b/docs/plugins.md
index cfa53417..1f6fd51d 100644
--- a/docs/plugins.md
+++ b/docs/plugins.md
@@ -194,7 +194,16 @@ must match exactly; no wildcards, paths or implicit subdomain grants.
 
 `NyaTerm.context` contains plugin identity/version and CSS theme variables;
 `NyaTerm.onContextChange(listener)` returns an unsubscribe function. Theme variables
-are applied to the iframe document automatically. This context contains no scope
+are applied to the iframe document automatically, including `--font-sans` and
+`--font-display` (the configured UI font stack) and `--font-mono`. Font changes
+are pushed to open panels without reloading them. The SDK defaults to the UI font
+and makes form controls inherit it; plugin styles should use
+`font-family: var(--font-sans, system-ui, sans-serif)` instead of a fixed family.
+Use `var(--font-mono, monospace)` for code. System-installed fonts are available
+inside the iframe, but the host's `@font-face` declarations are not inherited;
+package any required web fonts with the plugin and declare them in its CSS.
+Existing packages with a fixed font family need to update their CSS and be rebuilt.
+This context contains no scope
 token. Tokens are managed by the parent bridge. Scopes expire after 30 minutes;
 open panels renew at 25 minutes by recreating their document. Preserve needed
 nonsecret preferences in plugin storage.
diff --git a/plugins/examples/gpu-monitor/frontend/gpu.css b/plugins/examples/gpu-monitor/frontend/gpu.css
index abad1a57..5c725a1c 100644
--- a/plugins/examples/gpu-monitor/frontend/gpu.css
+++ b/plugins/examples/gpu-monitor/frontend/gpu.css
@@ -36,7 +36,7 @@ body,
 body {
   background: var(--background);
   color: var(--foreground);
-  font-family: system-ui, sans-serif;
+  font-family: var(--font-sans, system-ui, sans-serif);
 }
 .terminal-scroll {
   scrollbar-width: thin;
diff --git a/plugins/examples/session-toolbox/ui/index.html b/plugins/examples/session-toolbox/ui/index.html
index 8d0493ab..037c5cf7 100644
--- a/plugins/examples/session-toolbox/ui/index.html
+++ b/plugins/examples/session-toolbox/ui/index.html
@@ -11,9 +11,7 @@
       body {
         margin: 0;
         padding: 16px;
-        font:
-          13px/1.5 system-ui,
-          sans-serif;
+        font: 13px/1.5 var(--font-sans, system-ui, sans-serif);
         background: var(--df-bg, #111827);
         color: var(--df-fg, #e5e7eb);
       }
diff --git a/plugins/sdk/nyaterm.d.ts b/plugins/sdk/nyaterm.d.ts
index 9b5f85d8..9f7b03ba 100644
--- a/plugins/sdk/nyaterm.d.ts
+++ b/plugins/sdk/nyaterm.d.ts
@@ -9,6 +9,7 @@ type NyaTermJson =
 interface NyaTermPluginContext {
   pluginId: string;
   version: string;
+  /** Host CSS variables, including --font-sans, --font-display and --font-mono. */
   theme: Record<string, string>;
   language?: string;
   monitorIntervalSeconds?: number;
diff --git a/plugins/sdk/nyaterm.js b/plugins/sdk/nyaterm.js
index b8d2f2d5..996bae67 100644
--- a/plugins/sdk/nyaterm.js
+++ b/plugins/sdk/nyaterm.js
@@ -1,6 +1,14 @@
 /* NyaTerm Plugin UI SDK v1. Include this as a classic script before plugin code. */
 (() => {
   "use strict";
+  // A sandboxed document cannot inherit typography from the host. Keep these
+  // defaults easy for plugin styles to override, including code/monospace text.
+  const typography = document.createElement("style");
+  typography.textContent = `
+    :where(html) { font-family: var(--font-sans, system-ui, sans-serif); }
+    :where(button, input, select, textarea) { font-family: inherit; }
+  `;
+  document.head.prepend(typography);
   const pending = new Map();
   const contextListeners = new Set();
   const monitors = new Map();
diff --git a/plugins/templates/ui/index.html b/plugins/templates/ui/index.html
index 03886e1d..cfdb3999 100644
--- a/plugins/templates/ui/index.html
+++ b/plugins/templates/ui/index.html
@@ -7,7 +7,7 @@
     <style>
       body {
         margin: 16px;
-        font: 14px/1.5 system-ui;
+        font: 14px/1.5 var(--font-sans, system-ui, sans-serif);
         background: var(--df-bg, #111827);
         color: var(--df-fg, #e5e7eb);
       }
diff --git a/src/components/plugins/PluginPanel.tsx b/src/components/plugins/PluginPanel.tsx
index c3026612..b3bb8001 100644
--- a/src/components/plugins/PluginPanel.tsx
+++ b/src/components/plugins/PluginPanel.tsx
@@ -10,6 +10,9 @@ import { activeManifest, parsePluginPanelId, pluginApi } from "@/lib/plugins";
 import type { PluginScope } from "@/types/plugins";
 
 const THEME_VARIABLES = [
+  "--font-sans",
+  "--font-display",
+  "--font-mono",
   "--background",
   "--foreground",
   "--primary",