diff --git a/nebula_app/src/display/mod.rs b/nebula_app/src/display/mod.rs
index 5fc6283..a627cc0 100644
--- a/nebula_app/src/display/mod.rs
+++ b/nebula_app/src/display/mod.rs
@@ -1993,6 +1993,7 @@ impl Display {
             auth: crate::ssh_profiles::SshAuthMode::Auto,
             private_keys: Vec::new(),
             field: SshEditorField::Destination,
+            focus: crate::ux::FocusIndex::default(),
         });
         self.nebula_ssh_editor_rects = None;
         self.nebula_ssh_editor_open = true;
@@ -2026,6 +2027,7 @@ impl Display {
             auth: profile.auth,
             private_keys: profile.private_keys,
             field: SshEditorField::Destination,
+            focus: crate::ux::FocusIndex::default(),
         });
         self.nebula_ssh_editor_rects = None;
         self.nebula_ssh_editor_open = true;
@@ -2139,19 +2141,31 @@ impl Display {
         }
     }
 
-    pub fn ssh_editor_next_field(&mut self) {
+    pub fn ssh_editor_next_field(&mut self, reverse: bool) {
         if let Some(editor) = self.nebula_ssh_editor.as_mut() {
             editor.destination_selection.clear();
             editor.password_selection.clear();
             let shows_password = ssh_ui::auth_sections(editor.auth).0;
-            editor.field = match editor.field {
-                SshEditorField::Destination if shows_password => SshEditorField::Password,
-                SshEditorField::Destination => SshEditorField::Destination,
-                SshEditorField::Password => SshEditorField::Destination,
+            let count = if shows_password { 4 } else { 3 };
+            editor.focus.advance(count, reverse);
+            editor.field = match (shows_password, editor.focus.current()) {
+                (_, 0) => SshEditorField::Destination,
+                (true, 1) => SshEditorField::Password,
+                _ => editor.field,
             };
         }
     }
 
+    pub fn ssh_editor_activate_focus(&mut self) {
+        let Some(editor) = self.nebula_ssh_editor.as_ref() else { return };
+        let shows_password = ssh_ui::auth_sections(editor.auth).0;
+        match (shows_password, editor.focus.current()) {
+            (true, 2) | (false, 1) => self.close_ssh_editor(),
+            (true, 3) | (false, 2) => self.save_ssh_editor(),
+            _ => {},
+        }
+    }
+
     pub fn ssh_editor_toggle_save(&mut self) {
         if let Some(editor) = self.nebula_ssh_editor.as_mut() {
             editor.save_password = !editor.save_password;
@@ -2162,6 +2176,7 @@ impl Display {
         match self.ssh_editor_hit(x, y) {
             SshEditorHit::Destination => {
                 if let Some(editor) = self.nebula_ssh_editor.as_mut() {
+                    editor.focus.set(0, 4);
                     editor.destination_selection.clear();
                     editor.password_selection.clear();
                     editor.field = SshEditorField::Destination;
@@ -2174,6 +2189,7 @@ impl Display {
             },
             SshEditorHit::Password => {
                 if let Some(editor) = self.nebula_ssh_editor.as_mut() {
+                    editor.focus.set(1, 4);
                     editor.destination_selection.clear();
                     editor.password_selection.clear();
                     editor.field = SshEditorField::Password;
@@ -2211,8 +2227,26 @@ impl Display {
             SshEditorHit::SaveToggleBox | SshEditorHit::SaveToggleLabel => {
                 self.ssh_editor_toggle_save();
             },
-            SshEditorHit::Cancel => self.close_ssh_editor(),
-            SshEditorHit::Primary => self.save_ssh_editor(),
+            SshEditorHit::Cancel => {
+                if let Some(editor) = self.nebula_ssh_editor.as_mut() {
+                    let shows_password = ssh_ui::auth_sections(editor.auth).0;
+                    editor.focus.set(
+                        if shows_password { 2 } else { 1 },
+                        if shows_password { 4 } else { 3 },
+                    );
+                }
+                self.close_ssh_editor();
+            },
+            SshEditorHit::Primary => {
+                if let Some(editor) = self.nebula_ssh_editor.as_mut() {
+                    let shows_password = ssh_ui::auth_sections(editor.auth).0;
+                    editor.focus.set(
+                        if shows_password { 3 } else { 2 },
+                        if shows_password { 4 } else { 3 },
+                    );
+                }
+                self.save_ssh_editor();
+            },
             SshEditorHit::None => return false,
         }
         self.pending_update.dirty = true;
diff --git a/nebula_app/src/display/sftp_panel.rs b/nebula_app/src/display/sftp_panel.rs
index 30e6308..31d0847 100644
--- a/nebula_app/src/display/sftp_panel.rs
+++ b/nebula_app/src/display/sftp_panel.rs
@@ -565,12 +565,34 @@ pub(super) fn draw_text(
     );
 
     if let Some(error) = panel.editor_error.as_deref().or(snapshot.error.as_deref()) {
+        let user_error = crate::ux::UserFacingError::new(
+            "远端文件操作失败",
+            error,
+            "检查网络和目录权限，然后点击刷新重试。",
+        )
+        .retry(crate::ux::RetryAction::Retry);
         renderer.draw_chrome_text(
             size,
             layout.panel.0 + s(14.0),
             layout.list_y,
             Rgb::new(skin.danger.r, skin.danger.g, skin.danger.b),
-            &super::truncate_tab_label(error, 30),
+            &super::truncate_tab_label(&user_error.title, 30),
+            glyph_cache,
+        );
+        renderer.draw_chrome_text(
+            size,
+            layout.panel.0 + s(14.0),
+            layout.list_y + s(20.0),
+            skin.ink_dim,
+            &super::truncate_tab_label(&format!("原因：{}", user_error.cause), 30),
+            glyph_cache,
+        );
+        renderer.draw_chrome_text(
+            size,
+            layout.panel.0 + s(14.0),
+            layout.list_y + s(40.0),
+            skin.accent,
+            "建议：检查权限后点击刷新",
             glyph_cache,
         );
     } else if matches!(snapshot.phase, SftpPhase::Connecting | SftpPhase::Loading) {
@@ -624,12 +646,41 @@ pub(super) fn draw_text(
             );
         }
         if panel.visible_entries().is_empty() {
+            let empty = if panel.filter.is_empty() {
+                crate::ux::EmptyState::new(
+                    "此目录为空",
+                    "远端目录中还没有文件或子目录。",
+                    "使用上方上传按钮添加第一个文件。",
+                )
+            } else {
+                crate::ux::EmptyState::new(
+                    "没有匹配文件",
+                    "当前筛选条件未匹配任何远端条目。",
+                    "修改筛选词或清空筛选框。",
+                )
+            };
             renderer.draw_chrome_text(
                 size,
                 layout.panel.0 + s(14.0),
                 layout.list_y,
                 skin.ink_faint,
-                if panel.filter.is_empty() { "此目录为空" } else { "没有匹配文件" },
+                &empty.title,
+                glyph_cache,
+            );
+            renderer.draw_chrome_text(
+                size,
+                layout.panel.0 + s(14.0),
+                layout.list_y + s(20.0),
+                skin.ink_dim,
+                &super::truncate_tab_label(&empty.reason, 31),
+                glyph_cache,
+            );
+            renderer.draw_chrome_text(
+                size,
+                layout.panel.0 + s(14.0),
+                layout.list_y + s(40.0),
+                skin.accent,
+                &super::truncate_tab_label(&empty.action, 31),
                 glyph_cache,
             );
         }
diff --git a/nebula_app/src/display/side_panel.rs b/nebula_app/src/display/side_panel.rs
index e277fe0..334bb36 100644
--- a/nebula_app/src/display/side_panel.rs
+++ b/nebula_app/src/display/side_panel.rs
@@ -1317,6 +1317,45 @@ pub(super) fn draw_text(
                 let name = super::truncate_tab_label(&row.name, name_cols);
                 r.draw_chrome_text(size, name_x, ry, name_ink, &name, gc);
             }
+            if panel.file_rows().is_empty() {
+                let empty = if filtering {
+                    crate::ux::EmptyState::new(
+                        "没有匹配文件",
+                        "当前筛选词未匹配工作区内容。",
+                        "修改筛选词，或按 Esc 清空筛选。",
+                    )
+                } else if panel.root.is_none() {
+                    crate::ux::EmptyState::new(
+                        "没有可浏览的目录",
+                        "当前终端尚未报告工作目录。",
+                        "在终端中进入一个目录后点击刷新。",
+                    )
+                } else {
+                    crate::ux::EmptyState::new(
+                        "此目录为空",
+                        "当前工作目录中没有可显示的文件。",
+                        "在终端创建文件，或选择其他目录。",
+                    )
+                };
+                let y = layout.list_y + s(8.0);
+                r.draw_chrome_text(size, px + text_pad, y, sk.ink_strong, &empty.title, gc);
+                r.draw_chrome_text(
+                    size,
+                    px + text_pad,
+                    y + s(20.0),
+                    sk.ink_dim,
+                    &super::truncate_tab_label(&empty.reason, 32),
+                    gc,
+                );
+                r.draw_chrome_text(
+                    size,
+                    px + text_pad,
+                    y + s(40.0),
+                    sk.accent,
+                    &super::truncate_tab_label(&empty.action, 32),
+                    gc,
+                );
+            }
 
             // Drag ghost label, riding the chip pushed by `push_quads`.
             // Same chip-width formula as there (that pass has no cell_w), then
diff --git a/nebula_app/src/display/ssh_editor_render.rs b/nebula_app/src/display/ssh_editor_render.rs
index 33a5aed..0cd29aa 100644
--- a/nebula_app/src/display/ssh_editor_render.rs
+++ b/nebula_app/src/display/ssh_editor_render.rs
@@ -324,6 +324,8 @@ impl Display {
             accent,
             &skin,
             scale,
+            editor.focus.current(),
+            show_password,
         );
         for rect in [cancel_key_rect, primary_key_rect] {
             quads.push(UiQuad::solid(
@@ -597,6 +599,8 @@ fn button_quads(
     accent: Rgba,
     skin: &theme::Skin,
     scale: f32,
+    focus: usize,
+    shows_password: bool,
 ) {
     let s = |value: f32| value * scale;
     let primary_edge = Rgba::new(accent.r, accent.g, accent.b, if skin.is_light { 72 } else { 92 });
@@ -610,6 +614,22 @@ fn button_quads(
             edge,
         ));
     }
+    let cancel_focus = if shows_password { 2 } else { 1 };
+    let primary_focus = if shows_password { 3 } else { 2 };
+    for rect in
+        [(focus == cancel_focus).then_some(cancel), (focus == primary_focus).then_some(primary)]
+            .into_iter()
+            .flatten()
+    {
+        quads.push(UiQuad::solid(
+            rect.0 - s(2.0),
+            rect.1 - s(2.0),
+            rect.2 + s(4.0),
+            rect.3 + s(4.0),
+            s(10.0),
+            Rgba::new(skin.accent.r, skin.accent.g, skin.accent.b, 255),
+        ));
+    }
     quads.push(UiQuad::solid(cancel.0, cancel.1, cancel.2, cancel.3, s(8.0), skin.surface));
     quads.push(UiQuad::solid(primary.0, primary.1, primary.2, primary.3, s(8.0), skin.accent_soft));
     if hover == SshEditorHit::Cancel {
diff --git a/nebula_app/src/display/ssh_ui.rs b/nebula_app/src/display/ssh_ui.rs
index 27f23b3..46ae774 100644
--- a/nebula_app/src/display/ssh_ui.rs
+++ b/nebula_app/src/display/ssh_ui.rs
@@ -87,6 +87,7 @@ pub struct SshHostEditor {
     pub auth: SshAuthMode,
     pub private_keys: Vec<PathBuf>,
     pub field: SshEditorField,
+    pub focus: crate::ux::FocusIndex,
     pub error: Option<String>,
     pub(super) destination_selection: SelectAllState,
     pub(super) password_selection: SelectAllState,
diff --git a/nebula_app/src/input/keyboard.rs b/nebula_app/src/input/keyboard.rs
index 50b4a2f..8a071e7 100644
--- a/nebula_app/src/input/keyboard.rs
+++ b/nebula_app/src/input/keyboard.rs
@@ -279,8 +279,10 @@ impl<T: EventListener, A: ActionContext<T>> Processor<T, A> {
             if self.ctx.display().ssh_editor_active() {
                 match &key.logical_key {
                     Key::Named(NamedKey::Escape) => self.ctx.display().close_ssh_editor(),
-                    Key::Named(NamedKey::Enter) => self.ctx.display().save_ssh_editor(),
-                    Key::Named(NamedKey::Tab) => self.ctx.display().ssh_editor_next_field(),
+                    Key::Named(NamedKey::Enter) => self.ctx.display().ssh_editor_activate_focus(),
+                    Key::Named(NamedKey::Tab) => {
+                        self.ctx.display().ssh_editor_next_field(mods.shift_key())
+                    },
                     Key::Named(NamedKey::Backspace) => self.ctx.display().ssh_editor_backspace(),
                     Key::Character(c)
                         if mods.control_key() && !mods.alt_key() && c.eq_ignore_ascii_case("a") =>
diff --git a/nebula_app/src/main.rs b/nebula_app/src/main.rs
index 95d5ed7..2b10a09 100644
--- a/nebula_app/src/main.rs
+++ b/nebula_app/src/main.rs
@@ -36,9 +36,9 @@ mod daemon;
 mod display;
 mod event;
 #[cfg(windows)]
-mod font_install;
-#[cfg(windows)]
 mod file_uri;
+#[cfg(windows)]
+mod font_install;
 mod input;
 mod logging;
 #[cfg(target_os = "macos")]
@@ -71,6 +71,7 @@ mod ssh_session;
 #[cfg(windows)]
 mod ssh_sftp;
 mod string;
+mod ux;
 mod window_context;
 
 mod gl {
diff --git a/nebula_app/src/message_bar.rs b/nebula_app/src/message_bar.rs
index 73c3a7e..f2a38fd 100644
--- a/nebula_app/src/message_bar.rs
+++ b/nebula_app/src/message_bar.rs
@@ -35,12 +35,14 @@ impl Message {
         Message { text, ty, target: None }
     }
 
+    pub fn user_error(error: &crate::ux::UserFacingError) -> Message {
+        Message::new(error.message(), MessageType::Error)
+    }
+
     /// Formatted message text lines.
     pub fn text(&self, size_info: &SizeInfo) -> Vec<String> {
         let num_cols = size_info.columns();
-        let total_lines = (size_info.height()
-            - size_info.padding_y()
-            - size_info.padding_bottom())
+        let total_lines = (size_info.height() - size_info.padding_y() - size_info.padding_bottom())
             / size_info.cell_height();
         let max_lines = (total_lines as usize).saturating_sub(MIN_FREE_LINES);
         let button_len = CLOSE_BUTTON_TEXT.chars().count();
@@ -266,10 +268,10 @@ mod tests {
 
         let lines = message_buffer.message().unwrap().text(&size);
 
-        assert_eq!(lines, vec![
-            String::from("hahahahahahahahaha [X]"),
-            String::from("[MESSAGE TRUNCATED]   ")
-        ]);
+        assert_eq!(
+            lines,
+            vec![String::from("hahahahahahahahaha [X]"), String::from("[MESSAGE TRUNCATED]   ")]
+        );
     }
 
     #[test]
@@ -355,11 +357,10 @@ mod tests {
 
         let lines = message_buffer.message().unwrap().text(&size);
 
-        assert_eq!(lines, vec![
-            String::from("a [X]"),
-            String::from("bc   "),
-            String::from("defg ")
-        ]);
+        assert_eq!(
+            lines,
+            vec![String::from("a [X]"), String::from("bc   "), String::from("defg ")]
+        );
     }
 
     #[test]
@@ -371,11 +372,10 @@ mod tests {
 
         let lines = message_buffer.message().unwrap().text(&size);
 
-        assert_eq!(lines, vec![
-            String::from("ab  [X]"),
-            String::from("c 👩 d  "),
-            String::from("fgh    ")
-        ]);
+        assert_eq!(
+            lines,
+            vec![String::from("ab  [X]"), String::from("c 👩 d  "), String::from("fgh    ")]
+        );
     }
 
     #[test]
diff --git a/nebula_app/src/ux.rs b/nebula_app/src/ux.rs
new file mode 100644
index 0000000..4836ff9
--- /dev/null
+++ b/nebula_app/src/ux.rs
@@ -0,0 +1,229 @@
+//! Shared interaction-state contracts for Nebula's self-drawn UI.
+
+use std::time::{Duration, Instant};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum RetryAction {
+    None,
+    Retry,
+    OpenSettings,
+    OpenLogs,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct UserFacingError {
+    pub title: String,
+    pub cause: String,
+    pub suggestion: String,
+    pub retry: RetryAction,
+    pub details: Option<String>,
+}
+
+impl UserFacingError {
+    pub fn new(
+        title: impl Into<String>,
+        cause: impl Into<String>,
+        suggestion: impl Into<String>,
+    ) -> Self {
+        Self {
+            title: title.into(),
+            cause: cause.into(),
+            suggestion: suggestion.into(),
+            retry: RetryAction::None,
+            details: None,
+        }
+    }
+
+    pub fn retry(mut self, retry: RetryAction) -> Self {
+        self.retry = retry;
+        self
+    }
+
+    pub fn details(mut self, details: impl Into<String>) -> Self {
+        self.details = Some(details.into());
+        self
+    }
+
+    pub fn message(&self) -> String {
+        let mut message =
+            format!("{}\n原因：{}\n建议：{}", self.title, self.cause, self.suggestion);
+        let action = match self.retry {
+            RetryAction::None => None,
+            RetryAction::Retry => Some("操作：请重试"),
+            RetryAction::OpenSettings => Some("操作：打开设置检查配置"),
+            RetryAction::OpenLogs => Some("操作：打开日志查看诊断信息"),
+        };
+        if let Some(action) = action {
+            message.push('\n');
+            message.push_str(action);
+        }
+        if let Some(details) = &self.details {
+            message.push_str("\n详情：");
+            message.push_str(details);
+        }
+        message
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum TaskKind {
+    Determinate,
+    Indeterminate,
+    Short,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum TaskState {
+    Idle,
+    Running {
+        kind: TaskKind,
+        label: String,
+        started_at: Instant,
+        progress: Option<f32>,
+        cancellable: bool,
+    },
+    Failed(UserFacingError),
+}
+
+impl Default for TaskState {
+    fn default() -> Self {
+        Self::Idle
+    }
+}
+
+impl TaskState {
+    pub fn running(kind: TaskKind, label: impl Into<String>, cancellable: bool) -> Self {
+        Self::Running {
+            kind,
+            label: label.into(),
+            started_at: Instant::now(),
+            progress: None,
+            cancellable,
+        }
+    }
+
+    pub fn show_busy(&self, now: Instant) -> bool {
+        matches!(self, Self::Running { started_at, .. } if now.saturating_duration_since(*started_at) >= Duration::from_millis(150))
+    }
+
+    pub fn show_stage(&self, now: Instant) -> bool {
+        matches!(self, Self::Running { started_at, .. } if now.saturating_duration_since(*started_at) >= Duration::from_secs(1))
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct EmptyState {
+    pub title: String,
+    pub reason: String,
+    pub action: String,
+    pub shortcut: Option<String>,
+}
+
+impl EmptyState {
+    pub fn new(
+        title: impl Into<String>,
+        reason: impl Into<String>,
+        action: impl Into<String>,
+    ) -> Self {
+        Self { title: title.into(), reason: reason.into(), action: action.into(), shortcut: None }
+    }
+}
+
+/// Retains the last successful value while a refresh is in flight.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Refreshing<T> {
+    value: Option<T>,
+    refreshing: bool,
+    error: Option<UserFacingError>,
+}
+
+impl<T> Default for Refreshing<T> {
+    fn default() -> Self {
+        Self { value: None, refreshing: false, error: None }
+    }
+}
+
+impl<T> Refreshing<T> {
+    pub fn begin(&mut self) {
+        self.refreshing = true;
+        self.error = None;
+    }
+
+    pub fn succeed(&mut self, value: T) {
+        self.value = Some(value);
+        self.refreshing = false;
+        self.error = None;
+    }
+
+    pub fn fail(&mut self, error: UserFacingError) {
+        self.refreshing = false;
+        self.error = Some(error);
+    }
+
+    pub fn value(&self) -> Option<&T> {
+        self.value.as_ref()
+    }
+
+    pub fn is_refreshing(&self) -> bool {
+        self.refreshing
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub struct FocusIndex {
+    current: usize,
+}
+
+impl FocusIndex {
+    pub fn current(self) -> usize {
+        self.current
+    }
+
+    pub fn set(&mut self, index: usize, count: usize) {
+        self.current = index.min(count.saturating_sub(1));
+    }
+
+    pub fn advance(&mut self, count: usize, reverse: bool) {
+        if count == 0 {
+            self.current = 0;
+        } else if reverse {
+            self.current = (self.current + count - 1) % count;
+        } else {
+            self.current = (self.current + 1) % count;
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn structured_error_contains_cause_and_next_step() {
+        let error = UserFacingError::new("连接失败", "主机不可达", "检查地址后重试")
+            .retry(RetryAction::Retry)
+            .details("timeout");
+        let message = error.message();
+        assert!(message.contains("原因：主机不可达"));
+        assert!(message.contains("建议：检查地址后重试"));
+        assert!(message.contains("操作：请重试"));
+    }
+
+    #[test]
+    fn refresh_keeps_last_successful_value_on_failure() {
+        let mut state = Refreshing::default();
+        state.succeed(vec![1, 2]);
+        state.begin();
+        state.fail(UserFacingError::new("刷新失败", "磁盘不可用", "稍后重试"));
+        assert_eq!(state.value(), Some(&vec![1, 2]));
+    }
+
+    #[test]
+    fn focus_wraps_in_both_directions() {
+        let mut focus = FocusIndex::default();
+        focus.advance(3, true);
+        assert_eq!(focus.current(), 2);
+        focus.advance(3, false);
+        assert_eq!(focus.current(), 0);
+    }
+}
diff --git a/nebula_app/src/window_context.rs b/nebula_app/src/window_context.rs
index 4e319e9..3463c98 100644
--- a/nebula_app/src/window_context.rs
+++ b/nebula_app/src/window_context.rs
@@ -1030,12 +1030,14 @@ impl WindowContext {
                 },
                 Err(err) => {
                     error!("创建直连 SSH Pane 失败: {err}");
-                    self.message_buffer.push(crate::message_bar::Message::new(
-                        format!(
-                            "SSH {host} 连接创建失败：{err}。请检查地址/SSH 配置，右键编辑后重试。"
-                        ),
-                        crate::message_bar::MessageType::Error,
-                    ));
+                    let user_error = crate::ux::UserFacingError::new(
+                        format!("SSH {host} 连接创建失败"),
+                        "无法创建 SSH 会话，地址、认证方式或本机 SSH 配置可能无效。",
+                        "检查主机地址和认证配置，右键编辑该主机后重试。",
+                    )
+                    .retry(crate::ux::RetryAction::Retry)
+                    .details(err.to_string());
+                    self.message_buffer.push(crate::message_bar::Message::user_error(&user_error));
                     self.dirty = true;
                     self.display.window.request_redraw();
                     return;