feat(theme): 设计令牌生成器 + 主题管理器

- TOKENS_LIGHT / TOKENS_DARK：24 个语义颜色令牌（bg/text/border/accent/status）
- SIZES：圆角/间距/控件高度/字号
- FONT_STACK：跨平台字体回退
- build_qss(mode)：生成完整 QSS（覆盖 GroupBox/Button/Tab/Input/List/Scroll/CheckBox/Tooltip/Menu）
- ThemeManager：QObject，监听 styleHints().colorSchemeChanged 自动切换
- apply_theme(app)：入口函数，在 main() 创建 QApplication 后调用

业务层通过 setObjectName / setProperty('variant'|'status'|'role', ...) 命中 QSS。
状态色（success/warning/danger）走 status property，不再 inline setStyleSheet。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

+"""设计系统：Apple 高级浅色主题 + 浅深双模式。
+
+单一真相源 — 所有颜色 / 间距 / 圆角 / 字号在本模块定义，
+通过 build_qss(mode) 拼成完整 QSS 字符串应用到 QApplication。
+
+跟随系统切换：监听 QGuiApplication.styleHints().colorSchemeChanged，
+macOS 按时间自动切深色 / Windows 11 系统级深浅都会自动响应。
+
+业务代码不要写 inline setStyleSheet — 通过 setObjectName / setProperty
+让全局 QSS 命中。状态色（success/warning/danger）用 setProperty('status', ...)。
+"""
+from __future__ import annotations
+
+from PySide6.QtCore import QObject, Qt, Signal
+from PySide6.QtGui import QGuiApplication
+from PySide6.QtWidgets import QApplication
+
+# =============================================================================
+# 设计令牌
+# =============================================================================
+
+FONT_STACK = (
+    '"-apple-system", "SF Pro Text", "PingFang SC", '
+    '"Microsoft YaHei UI", "Segoe UI Variable", "Segoe UI", sans-serif'
+)
+
+TOKENS_LIGHT: dict[str, str] = {
+    # 表面层级
+    "bg_canvas": "#fbfbfd",
+    "bg_surface": "#ffffff",
+    "bg_elevated": "#ffffff",
+    "bg_subtle": "#f4f4f7",
+    "bg_hover": "#f0f0f3",
+
+    # 文字层级
+    "text_primary": "#1d1d1f",
+    "text_secondary": "#6e6e73",
+    "text_tertiary": "#86868b",
+    "text_on_accent": "#ffffff",
+    "text_on_danger": "#ffffff",
+
+    # 边框 / 分隔
+    "border_default": "rgba(0, 0, 0, 0.10)",
+    "border_strong": "rgba(0, 0, 0, 0.18)",
+    "border_focus": "#0071e3",
+    "divider": "rgba(0, 0, 0, 0.06)",
+
+    # 主色（accent）
+    "accent": "#0071e3",
+    "accent_hover": "#0077ed",
+    "accent_pressed": "#0062c4",
+    "accent_subtle": "rgba(0, 113, 227, 0.08)",
+    "accent_subtle_hover": "rgba(0, 113, 227, 0.14)",
+
+    # 状态色
+    "success": "#34c759",
+    "warning": "#ff9500",
+    "danger": "#ff3b30",
+    "danger_hover": "#ff5247",
+    "danger_subtle": "rgba(255, 59, 48, 0.10)",
+}
+
+TOKENS_DARK: dict[str, str] = {
+    "bg_canvas": "#1a1a1c",
+    "bg_surface": "#2c2c2e",
+    "bg_elevated": "#3a3a3c",
+    "bg_subtle": "#242426",
+    "bg_hover": "#34343a",
+
+    "text_primary": "#ffffff",
+    "text_secondary": "#98989d",
+    "text_tertiary": "#6e6e73",
+    "text_on_accent": "#ffffff",
+    "text_on_danger": "#ffffff",
+
+    "border_default": "rgba(255, 255, 255, 0.10)",
+    "border_strong": "rgba(255, 255, 255, 0.20)",
+    "border_focus": "#0a84ff",
+    "divider": "rgba(255, 255, 255, 0.06)",
+
+    "accent": "#0a84ff",
+    "accent_hover": "#1d8cff",
+    "accent_pressed": "#006edc",
+    "accent_subtle": "rgba(10, 132, 255, 0.16)",
+    "accent_subtle_hover": "rgba(10, 132, 255, 0.24)",
+
+    "success": "#30d158",
+    "warning": "#ff9f0a",
+    "danger": "#ff453a",
+    "danger_hover": "#ff5b50",
+    "danger_subtle": "rgba(255, 69, 58, 0.16)",
+}
+
+# 尺寸 / 圆角 / 间距 ─ 浅深一致
+SIZES: dict[str, str] = {
+    "radius_sm": "4px",
+    "radius_md": "8px",
+    "radius_lg": "12px",
+    "radius_pill": "980px",
+
+    "space_1": "4px",
+    "space_2": "8px",
+    "space_3": "12px",
+    "space_4": "16px",
+    "space_5": "20px",
+    "space_6": "24px",
+
+    "control_h_sm": "26px",
+    "control_h_md": "32px",
+    "control_h_lg": "40px",
+
+    "font_xs": "10pt",
+    "font_sm": "11pt",
+    "font_base": "12pt",
+    "font_lg": "14pt",
+    "font_xl": "17pt",
+}
+
+
+# =============================================================================
+# QSS 构建
+# =============================================================================
+
+def build_qss(mode: str) -> str:
+    """根据 mode（'light'/'dark'）拼出完整 QSS。"""
+    c = TOKENS_DARK if mode == "dark" else TOKENS_LIGHT
+    s = SIZES
+    f = FONT_STACK
+
+    return f"""
+/* ========== 全局 ========== */
+* {{
+    font-family: {f};
+    color: {c['text_primary']};
+}}
+
+QWidget {{
+    background-color: {c['bg_canvas']};
+    color: {c['text_primary']};
+    font-size: {s['font_base']};
+}}
+
+QMainWindow, QDialog {{
+    background-color: {c['bg_canvas']};
+}}
+
+/* 二级弹窗（QMessageBox 等）走 surface 颜色，凸出于主窗口 */
+QMessageBox {{
+    background-color: {c['bg_surface']};
+}}
+QMessageBox QLabel {{
+    background: transparent;
+    color: {c['text_primary']};
+    font-size: {s['font_base']};
+}}
+
+/* ========== 文字 ========== */
+QLabel {{
+    background: transparent;
+    color: {c['text_primary']};
+}}
+QLabel[role="secondary"] {{
+    color: {c['text_secondary']};
+}}
+QLabel[role="muted"] {{
+    color: {c['text_tertiary']};
+    font-size: {s['font_sm']};
+}}
+QLabel[role="caption"] {{
+    color: {c['text_secondary']};
+    font-size: {s['font_xs']};
+    text-transform: uppercase;
+    letter-spacing: 1px;
+}}
+QLabel[role="title"] {{
+    color: {c['text_primary']};
+    font-size: {s['font_xl']};
+    font-weight: 600;
+}}
+
+/* 状态色 — 业务用 setProperty('status', '...') 命中 */
+QLabel[status="success"] {{ color: {c['success']}; }}
+QLabel[status="warning"] {{ color: {c['warning']}; }}
+QLabel[status="danger"]  {{ color: {c['danger']}; }}
+QLabel[status="muted"]   {{ color: {c['text_tertiary']}; }}
+QLabel[status="info"]    {{ color: {c['accent']}; }}
+
+/* ========== 卡片 / GroupBox ========== */
+QGroupBox {{
+    background-color: {c['bg_surface']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_md']};
+    margin-top: 14px;
+    padding: {s['space_4']} {s['space_3']} {s['space_3']} {s['space_3']};
+    font-weight: 600;
+    font-size: {s['font_sm']};
+    color: {c['text_secondary']};
+}}
+QGroupBox::title {{
+    subcontrol-origin: margin;
+    subcontrol-position: top left;
+    left: {s['space_3']};
+    padding: 0 {s['space_2']};
+    color: {c['text_secondary']};
+    background: transparent;
+    text-transform: uppercase;
+    letter-spacing: 1px;
+    font-size: {s['font_xs']};
+}}
+
+/* ========== 按钮 ========== */
+QPushButton {{
+    background-color: {c['bg_surface']};
+    color: {c['text_primary']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_md']};
+    padding: 6px 14px;
+    min-height: {s['control_h_md']};
+    font-size: {s['font_sm']};
+    font-weight: 500;
+}}
+QPushButton:hover {{
+    background-color: {c['bg_hover']};
+    border-color: {c['border_strong']};
+}}
+QPushButton:pressed {{
+    background-color: {c['bg_subtle']};
+}}
+QPushButton:disabled {{
+    color: {c['text_tertiary']};
+    background-color: {c['bg_subtle']};
+    border-color: {c['border_default']};
+}}
+QPushButton:focus {{
+    outline: none;
+    border-color: {c['accent']};
+}}
+
+/* 主按钮（"生成图片"等）— pill 圆角 + 实色背景 */
+QPushButton[variant="primary"] {{
+    background-color: {c['accent']};
+    color: {c['text_on_accent']};
+    border: 1px solid {c['accent']};
+    border-radius: {s['radius_pill']};
+    padding: 8px 22px;
+    min-height: {s['control_h_lg']};
+    font-weight: 600;
+}}
+QPushButton[variant="primary"]:hover {{
+    background-color: {c['accent_hover']};
+    border-color: {c['accent_hover']};
+}}
+QPushButton[variant="primary"]:pressed {{
+    background-color: {c['accent_pressed']};
+    border-color: {c['accent_pressed']};
+}}
+QPushButton[variant="primary"]:disabled {{
+    background-color: {c['accent_subtle']};
+    color: {c['text_tertiary']};
+    border-color: transparent;
+}}
+
+/* 危险按钮 */
+QPushButton[variant="danger"] {{
+    background-color: {c['bg_surface']};
+    color: {c['danger']};
+    border: 1px solid {c['danger']};
+}}
+QPushButton[variant="danger"]:hover {{
+    background-color: {c['danger_subtle']};
+}}
+QPushButton[variant="danger"]:pressed {{
+    background-color: {c['danger']};
+    color: {c['text_on_danger']};
+}}
+
+/* 幽灵按钮（图标按钮等） */
+QPushButton[variant="ghost"] {{
+    background-color: transparent;
+    border: 1px solid transparent;
+    color: {c['text_secondary']};
+}}
+QPushButton[variant="ghost"]:hover {{
+    background-color: {c['accent_subtle']};
+    color: {c['accent']};
+}}
+
+/* 链接按钮 — 像超链接 */
+QPushButton[variant="link"] {{
+    background-color: transparent;
+    border: none;
+    color: {c['accent']};
+    padding: 2px 6px;
+    min-height: 0;
+}}
+QPushButton[variant="link"]:hover {{
+    color: {c['accent_hover']};
+    text-decoration: underline;
+}}
+
+/* ========== 输入框 ========== */
+QLineEdit, QTextEdit, QPlainTextEdit {{
+    background-color: {c['bg_surface']};
+    color: {c['text_primary']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_md']};
+    padding: 6px 10px;
+    selection-background-color: {c['accent']};
+    selection-color: {c['text_on_accent']};
+    font-size: {s['font_base']};
+}}
+QLineEdit:focus, QTextEdit:focus, QPlainTextEdit:focus {{
+    border: 2px solid {c['accent']};
+    padding: 5px 9px;
+}}
+QLineEdit:disabled, QTextEdit:disabled, QPlainTextEdit:disabled {{
+    background-color: {c['bg_subtle']};
+    color: {c['text_tertiary']};
+}}
+QLineEdit[placeholder="true"], QTextEdit[placeholder="true"] {{
+    color: {c['text_tertiary']};
+}}
+
+/* ========== 下拉框 ========== */
+QComboBox {{
+    background-color: {c['bg_surface']};
+    color: {c['text_primary']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_md']};
+    padding: 5px 10px;
+    min-height: {s['control_h_md']};
+    min-width: 100px;
+}}
+QComboBox:hover {{
+    border-color: {c['border_strong']};
+}}
+QComboBox:focus {{
+    border: 2px solid {c['accent']};
+    padding: 4px 9px;
+}}
+QComboBox::drop-down {{
+    width: 20px;
+    border: none;
+    background: transparent;
+}}
+QComboBox QAbstractItemView {{
+    background-color: {c['bg_elevated']};
+    color: {c['text_primary']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_md']};
+    selection-background-color: {c['accent_subtle']};
+    selection-color: {c['text_primary']};
+    padding: 4px;
+    outline: none;
+}}
+QComboBox QAbstractItemView::item {{
+    padding: 6px 10px;
+    border-radius: {s['radius_sm']};
+}}
+QComboBox QAbstractItemView::item:hover {{
+    background-color: {c['accent_subtle']};
+}}
+
+/* ========== Tab ========== */
+QTabWidget::pane {{
+    border: none;
+    background-color: {c['bg_canvas']};
+    top: -1px;
+}}
+QTabWidget::tab-bar {{
+    left: 4px;
+}}
+QTabBar {{
+    background: transparent;
+    qproperty-drawBase: 0;
+}}
+QTabBar::tab {{
+    background: transparent;
+    color: {c['text_secondary']};
+    padding: 8px 16px;
+    margin: 0 2px;
+    border: none;
+    border-bottom: 2px solid transparent;
+    font-size: {s['font_base']};
+    min-width: 80px;
+}}
+QTabBar::tab:hover {{
+    color: {c['text_primary']};
+}}
+QTabBar::tab:selected {{
+    color: {c['accent']};
+    border-bottom: 2px solid {c['accent']};
+    font-weight: 600;
+}}
+QTabBar::tab:disabled {{
+    color: {c['text_tertiary']};
+}}
+
+/* ========== 列表 ========== */
+QListWidget, QListView, QTreeWidget, QTreeView {{
+    background-color: {c['bg_surface']};
+    color: {c['text_primary']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_md']};
+    outline: none;
+    padding: 4px;
+}}
+QListWidget::item, QListView::item {{
+    padding: 8px;
+    border-radius: {s['radius_sm']};
+    color: {c['text_primary']};
+}}
+QListWidget::item:hover, QListView::item:hover {{
+    background-color: {c['bg_hover']};
+}}
+QListWidget::item:selected, QListView::item:selected {{
+    background-color: {c['accent_subtle']};
+    color: {c['text_primary']};
+}}
+
+/* ========== 滚动区 ========== */
+QScrollArea {{
+    background-color: {c['bg_canvas']};
+    border: none;
+}}
+QScrollArea > QWidget > QWidget {{
+    background-color: transparent;
+}}
+
+/* ========== 滚动条（Apple 隐式风格）========== */
+QScrollBar:vertical {{
+    background: transparent;
+    width: 10px;
+    margin: 2px;
+    border: none;
+}}
+QScrollBar::handle:vertical {{
+    background: {c['border_strong']};
+    border-radius: 3px;
+    min-height: 30px;
+}}
+QScrollBar::handle:vertical:hover {{
+    background: {c['text_tertiary']};
+}}
+QScrollBar::add-line:vertical, QScrollBar::sub-line:vertical {{
+    height: 0;
+    background: transparent;
+    border: none;
+}}
+QScrollBar::add-page:vertical, QScrollBar::sub-page:vertical {{
+    background: transparent;
+}}
+
+QScrollBar:horizontal {{
+    background: transparent;
+    height: 10px;
+    margin: 2px;
+    border: none;
+}}
+QScrollBar::handle:horizontal {{
+    background: {c['border_strong']};
+    border-radius: 3px;
+    min-width: 30px;
+}}
+QScrollBar::handle:horizontal:hover {{
+    background: {c['text_tertiary']};
+}}
+QScrollBar::add-line:horizontal, QScrollBar::sub-line:horizontal {{
+    width: 0;
+    background: transparent;
+    border: none;
+}}
+QScrollBar::add-page:horizontal, QScrollBar::sub-page:horizontal {{
+    background: transparent;
+}}
+
+/* ========== 进度条 ========== */
+QProgressBar {{
+    background-color: {c['bg_subtle']};
+    border: none;
+    border-radius: 4px;
+    height: 6px;
+    text-align: center;
+    color: {c['text_secondary']};
+    font-size: {s['font_xs']};
+}}
+QProgressBar::chunk {{
+    background-color: {c['accent']};
+    border-radius: 4px;
+}}
+
+/* ========== 复选 / 单选 ========== */
+QCheckBox, QRadioButton {{
+    color: {c['text_primary']};
+    spacing: 6px;
+    background: transparent;
+}}
+QCheckBox::indicator, QRadioButton::indicator {{
+    width: 16px;
+    height: 16px;
+}}
+QCheckBox::indicator:unchecked {{
+    background: {c['bg_surface']};
+    border: 1px solid {c['border_strong']};
+    border-radius: 3px;
+}}
+QCheckBox::indicator:checked {{
+    background: {c['accent']};
+    border: 1px solid {c['accent']};
+    border-radius: 3px;
+}}
+QRadioButton::indicator:unchecked {{
+    background: {c['bg_surface']};
+    border: 1px solid {c['border_strong']};
+    border-radius: 8px;
+}}
+QRadioButton::indicator:checked {{
+    background: {c['accent']};
+    border: 1px solid {c['accent']};
+    border-radius: 8px;
+}}
+
+/* ========== 工具提示 ========== */
+QToolTip {{
+    background-color: {c['bg_elevated']};
+    color: {c['text_primary']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_sm']};
+    padding: 4px 8px;
+    font-size: {s['font_sm']};
+}}
+
+/* ========== 菜单 ========== */
+QMenu {{
+    background-color: {c['bg_elevated']};
+    color: {c['text_primary']};
+    border: 1px solid {c['border_default']};
+    border-radius: {s['radius_md']};
+    padding: 4px;
+}}
+QMenu::item {{
+    padding: 6px 16px;
+    border-radius: {s['radius_sm']};
+}}
+QMenu::item:selected {{
+    background-color: {c['accent_subtle']};
+    color: {c['text_primary']};
+}}
+QMenu::separator {{
+    height: 1px;
+    background: {c['divider']};
+    margin: 4px 6px;
+}}
+
+/* ========== 分割器 ========== */
+QSplitter::handle {{
+    background-color: {c['divider']};
+}}
+QSplitter::handle:horizontal {{
+    width: 1px;
+}}
+QSplitter::handle:vertical {{
+    height: 1px;
+}}
+
+/* ========== 任务队列 sidebar ========== */
+#taskQueueSidebar {{
+    background-color: {c['bg_surface']};
+    border-left: 1px solid {c['divider']};
+}}
+#sidebarHeader {{
+    background-color: {c['bg_surface']};
+    border-bottom: 1px solid {c['divider']};
+    min-height: 40px;
+    max-height: 40px;
+}}
+#sidebarHeader QLabel {{
+    color: {c['text_primary']};
+    font-size: {s['font_base']};
+    font-weight: 600;
+    padding: 0 12px;
+}}
+
+/* ========== 登录对话框 ========== */
+#loginDialog {{
+    background-color: {c['bg_canvas']};
+}}
+#loginDialog QLabel#loginTitle {{
+    font-size: {s['font_xl']};
+    font-weight: 600;
+    color: {c['text_primary']};
+}}
+#loginDialog QLabel#loginSubtitle {{
+    font-size: {s['font_sm']};
+    color: {c['text_secondary']};
+}}
+
+/* ========== 预览区占位 ========== */
+#previewPlaceholder {{
+    color: {c['text_tertiary']};
+    background: {c['bg_subtle']};
+    border-radius: {s['radius_md']};
+}}
+"""
+
+
+# =============================================================================
+# 主题管理器
+# =============================================================================
+
+def _detect_system_mode() -> str:
+    """检测当前系统色彩偏好。Qt 6.5+ 支持，回退到 light。"""
+    try:
+        scheme = QGuiApplication.styleHints().colorScheme()
+        if scheme == Qt.ColorScheme.Dark:
+            return "dark"
+        return "light"
+    except Exception:
+        return "light"
+
+
+class ThemeManager(QObject):
+    """全局主题管理器。监听系统色彩偏好变化，自动切换 QSS。
+
+    使用：在 main() 创建 QApplication 后调用 apply_theme(app) 即可。
+    业务代码不需要直接接触 ThemeManager。
+
+    通过 force_mode('light'|'dark'|None) 可以强制锁定，传 None 恢复跟随系统。
+    """
+
+    theme_changed = Signal(str)  # 'light' | 'dark'
+
+    def __init__(self, app: QApplication):
+        super().__init__(app)
+        self._app = app
+        self._forced_mode: str | None = None
+        self._current_mode: str = _detect_system_mode()
+        self._apply_qss()
+
+        # 监听系统色彩切换
+        try:
+            QGuiApplication.styleHints().colorSchemeChanged.connect(
+                self._on_system_color_scheme_changed
+            )
+        except Exception:
+            # Qt 版本不支持 / 平台不发射，无所谓
+            pass
+
+    def current_mode(self) -> str:
+        return self._current_mode
+
+    def force_mode(self, mode: str | None) -> None:
+        """锁定主题。None = 跟随系统。"""
+        self._forced_mode = mode
+        new_mode = mode if mode in ("light", "dark") else _detect_system_mode()
+        if new_mode != self._current_mode:
+            self._current_mode = new_mode
+            self._apply_qss()
+            self.theme_changed.emit(new_mode)
+
+    def _on_system_color_scheme_changed(self, scheme) -> None:
+        if self._forced_mode in ("light", "dark"):
+            return  # 用户锁定模式时不响应系统切换
+        new_mode = "dark" if scheme == Qt.ColorScheme.Dark else "light"
+        if new_mode != self._current_mode:
+            self._current_mode = new_mode
+            self._apply_qss()
+            self.theme_changed.emit(new_mode)
+
+    def _apply_qss(self) -> None:
+        self._app.setStyleSheet(build_qss(self._current_mode))
+
+
+def apply_theme(app: QApplication) -> ThemeManager:
+    """主题应用入口。在 main() 创建 QApplication 后立即调用。
+
+    返回 ThemeManager 实例，调用方应持有引用以保持信号连接（否则会被
+    Python GC 当作未引用的 QObject 回收，导致系统切换失效）。
+    """
+    return ThemeManager(app)