body {
            font-family: var(--font-ui);
            background-color: var(--bg-gray);
            color: var(--text-primary);
            overflow: hidden; 
            font-size: 14px;
            line-height: 1.5;
            height: 100vh; height: 100dvh;
            transition: background-color 0.3s ease, color 0.3s ease;
        }    
    
        /* =====================================================
           布局核心 CSS (已剥离所有基础色板与 Reset)
           ===================================================== */
        body::before {
            content: ''; position: fixed; inset: 0; z-index: -1; pointer-events: none;
            background-image: radial-gradient(var(--border-color) 1px, transparent 1px);
            background-size: 24px 24px; opacity: 0.6;
            mask-image: radial-gradient(circle at 50% 50%, black, transparent 90%);
        }

        .top-nav { background: rgba(255, 255, 255, 0.95); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid var(--border-color); height: var(--header-height); display: flex; align-items: center; padding: 0; position: fixed; top: 0; left: 0; right: 0; z-index: 1000; transition: all 0.3s ease; }
        .top-nav.layer-up { z-index: 2006 !important; }
        [data-theme="dark"] .top-nav { background: rgba(30, 41, 59, 0.95); }

        .logo { display: flex; align-items: center; gap: 12px; height: 100%; width: var(--sidebar-width); padding-left: 20px; flex-shrink: 0; cursor: pointer; user-select: none; transition: width 0.3s; }
        .logo.collapsed { width: var(--sidebar-mini-width); padding-left: 0; justify-content: center; }
        .logo.collapsed .logo-text { display: none; opacity: 0; }
        .logo-box { width: 36px; height: 36px; background: linear-gradient(135deg, var(--primary-color), var(--primary-dark)); border-radius: 8px; display: flex; align-items: center; justify-content: center; box-shadow: 0 4px 10px rgba(59, 130, 246, 0.3); flex-shrink: 0; }
        .logo-box i { color: #fff; font-size: 18px; }
        .logo-text { display: flex; flex-direction: column; line-height: 1.2; overflow: hidden; white-space: nowrap; }
        .logo-title { font-size: 16px; font-weight: 800; color: var(--text-primary); letter-spacing: -0.5px; transition: color 0.3s; }
        .logo-subtitle { font-size: 10px; color: var(--primary-light); font-weight: 700; letter-spacing: 0.5px; text-transform: uppercase; }

        .pc-toggle, .hamburger { width: 36px; height: 36px; border-radius: var(--radius-sm); color: var(--text-secondary); display: flex; align-items: center; justify-content: center; transition: all 0.2s; cursor: pointer; margin-left: 12px; flex-shrink: 0; font-size: 20px; }
        .pc-toggle:hover { background: var(--bg-hover); color: var(--primary-color); }
        .hamburger { display: none; }

        .top-menu { display: flex; gap: 6px; padding: 4px; margin-left: 12px; margin-right: auto; overflow-x: auto; overflow-y: hidden; align-items: center; scrollbar-width: none; }
        .top-menu::-webkit-scrollbar { display: none; }
        .top-menu-item { padding: 6px 14px; border-radius: 6px; cursor: pointer; color: var(--text-secondary); font-size: 13px; font-weight: 500; white-space: nowrap; display: flex; align-items: center; gap: 8px; transition: all 0.2s ease; flex-shrink: 0; user-select: none; }
        .top-menu-item:hover { color: var(--text-primary); background: var(--bg-hover); }
        .top-menu-item.active { background: var(--bg-active); color: var(--primary-color); font-weight: 600; }
        [data-theme="dark"] .top-menu-item.active { color: var(--primary-light); }

        .immersive-switch-wrapper { display: flex; align-items: center; margin-right: 16px; }
        .theme-switch { display: inline-block; height: 24px; position: relative; width: 44px; }
        .theme-switch input { display: none; }
        .slider { background-color: #ccc; bottom: 0; cursor: pointer; left: 0; position: absolute; right: 0; top: 0; transition: .4s; border-radius: 34px; }
        [data-theme="dark"] .slider { background-color: #475569; }
        .slider:before { background-color: #fff; bottom: 2px; content: ""; height: 20px; left: 2px; position: absolute; transition: .4s; width: 20px; border-radius: 50%; box-shadow: 0 2px 4px rgba(0,0,0,0.2); }
        input:checked + .slider { background-color: var(--primary-color); }
        input:checked + .slider:before { transform: translateX(20px); }

        .tool-icon-btn { width: 36px; height: 36px; display: flex; align-items: center; justify-content: center; border-radius: 50%; cursor: pointer; color: var(--text-secondary); transition: all 0.2s ease; margin-right: 12px; font-size: 18px; }
        .tool-icon-btn:hover { background: var(--bg-hover); color: var(--primary-color); transform: rotate(15deg); }
        #langBtn:hover { transform: scale(1.1); } 

        .user-pill { display: flex; align-items: center; gap: 10px; padding: 4px 12px 4px 4px; border-radius: 30px; cursor: pointer; transition: all 0.2s ease; flex-shrink: 0; margin-right: 24px; border: 1px solid transparent; }
        .user-pill:hover { background: var(--bg-hover); border-color: var(--border-color); }
        .user-avatar { width: 30px; height: 30px; border-radius: 50%; background: linear-gradient(135deg, #2563eb, #60a5fa); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 12px; }
        .user-name { font-size: 13px; font-weight: 600; color: var(--text-primary); }

        .sidebar { background: var(--bg-white); width: var(--sidebar-width); position: fixed; left: 0; top: var(--header-height); bottom: 0; border-right: 1px solid var(--border-color); overflow-y: auto; overflow-x: hidden; transition: all 0.3s; z-index: 999; padding: 16px 0; scrollbar-width: none; }
        .sidebar::-webkit-scrollbar { display: none; }
        .sidebar.collapsed { width: var(--sidebar-mini-width); }
        .sidebar.collapsed .menu-group-header span, .sidebar.collapsed .menu-group-header .toggle, .sidebar.collapsed .menu-item span, .sidebar.collapsed .menu-item .blank-icon { display: none; }
        .sidebar.collapsed .menu-item { justify-content: center; padding: 12px 0; margin: 4px 8px; }
        .sidebar.collapsed .menu-item i { margin-right: 0; font-size: 18px; width: 24px; text-align: center; }
        .sidebar.collapsed .menu-group-header { justify-content: center; padding: 12px 0; height: 20px; }
        .sidebar.collapsed .menu-group-header::after { content: ''; display: block; width: 20px; height: 2px; background: var(--border-color); border-radius: 2px; }
        .mobile-logo { display: none; padding: 16px 20px; border-bottom: 1px solid var(--border-color); align-items: center; gap: 12px; margin-bottom: 10px; cursor: pointer; }

        .menu-group { margin-bottom: 4px; }
        .menu-group-header { padding: 10px 24px; font-size: 11px; font-weight: 700; color: var(--text-disabled); cursor: pointer; display: flex; align-items: center; justify-content: space-between; user-select: none; transition: all 0.2s; text-transform: uppercase; }
        .menu-group-header:hover { color: var(--text-primary); }
        .menu-group.collapsed-group .toggle { transform: rotate(-90deg); }
        .menu-group.collapsed-group .menu-items { max-height: 0; opacity: 0; }
        .menu-items { max-height: 2000px; opacity: 1; overflow: hidden; transition: all 0.3s; padding: 0 10px; }
        .menu-item { padding: 10px 14px; margin-bottom: 2px; border-radius: var(--radius-sm); cursor: pointer; color: var(--text-secondary); font-size: 14px; font-weight: 500; display: flex; align-items: center; gap: 12px; transition: all 0.2s; white-space: nowrap; user-select: none; }
        .menu-item:hover { background: var(--bg-hover); color: var(--text-primary); transform: translateX(2px); }
        .menu-item.active { background: var(--bg-active); color: var(--primary-color); font-weight: 600; }
        [data-theme="dark"] .menu-item.active { color: var(--primary-light); }
        .menu-item i { font-size: 16px; width: 20px; text-align: center; flex-shrink: 0; }

        .content { position: fixed; top: var(--header-height); left: var(--sidebar-width); right: 0; bottom: 0; background: var(--bg-gray); transition: all 0.3s; }
        .content.collapsed { left: var(--sidebar-mini-width); }
        .content-wrapper { width: 100%; height: 100%; position: relative; background: var(--bg-white); border-radius: var(--radius-md); box-shadow: var(--shadow-sm); overflow: hidden; border: 1px solid var(--border-color); transition: all 0.3s; }
        .content-frame { width: 100%; height: 100%; border: none; opacity: 0; transition: opacity 0.4s; display: none; }
        .content-frame.loaded { opacity: 1; }

        .loader-mask { position: absolute; inset: 0; background: var(--bg-white); display: flex; flex-direction: column; align-items: center; justify-content: center; z-index: 50; transition: opacity 0.3s; }
        .loader-mask.hide { opacity: 0; pointer-events: none; }
        .spinner { width: 32px; height: 32px; border: 3px solid transparent; border-top-color: var(--primary-color); border-radius: 50%; animation: spin 0.8s infinite cubic-bezier(0.5, 0, 0.5, 1); position: relative; }
        .spinner::after { content: ''; position: absolute; inset: 2px; border-radius: 50%; border: 3px solid transparent; border-top-color: var(--primary-light); opacity: 0.4; animation: spin 1.5s linear infinite; }
        @keyframes spin { to { transform: rotate(360deg); } }
        .loading-text { margin-top: 16px; color: var(--text-secondary); font-size: 13px; font-weight: 500; }

        .error-overlay { position: absolute; inset: 0; background: var(--bg-white); display: none; flex-direction: column; align-items: center; justify-content: center; z-index: 10; }
        .error-overlay.show { display: flex; }
        .retry-btn { padding: 8px 20px; background: var(--primary-color); color: white; border: none; border-radius: var(--radius-sm); cursor: pointer; font-size: 13px; font-weight: 600; display: flex; align-items: center; gap: 8px; box-shadow: 0 4px 10px rgba(59, 130, 246, 0.3); }
        .retry-btn:active { transform: scale(0.96); }

        .floating-overlay { position: fixed; inset: 0; background: transparent; z-index: 2004; display: none; }
        .floating-window { position: fixed; background: var(--bg-white); border-radius: var(--radius-md); box-shadow: var(--shadow-float); border: 1px solid var(--border-color); z-index: 2010; overflow: hidden; display: none; resize: both; min-width: 300px; min-height: 200px; max-width: 98vw; max-height: 98vh; animation: popIn 0.3s cubic-bezier(0.18, 0.89, 0.32, 1.28); transition: background-color 0.3s, border-color 0.3s; }
        @keyframes popIn { from { opacity: 0; transform: scale(0.9); } to { opacity: 1; transform: scale(1); } }
        .floating-header { background: rgba(255, 255, 255, 0.98); border-bottom: 1px solid var(--border-color); padding: 10px 16px; display: flex; justify-content: space-between; align-items: center; cursor: move; user-select: none; height: 48px; transition: background-color 0.3s, border-color 0.3s; }
        [data-theme="dark"] .floating-header { background: rgba(30, 41, 59, 0.98); }
        .floating-title { font-size: 14px; font-weight: 600; color: var(--text-primary); display: flex; align-items: center; gap: 8px; }
        .floating-controls { display: flex; gap: 8px; }
        .floating-btn { width: 28px; height: 28px; border-radius: 6px; display: flex; align-items: center; justify-content: center; cursor: pointer; color: var(--text-secondary); transition: all 0.2s; background: transparent; border: none; font-size: 14px; }
        .floating-btn:hover { background: var(--bg-hover); color: var(--text-primary); }
        .floating-btn.close:hover { background: #fee2e2; color: #ef4444; }
        .floating-content { width: 100%; height: calc(100% - 48px); position: relative; overflow: auto; scrollbar-width: none; -ms-overflow-style: none; background: var(--bg-white); }
        .floating-content::-webkit-scrollbar { display: none; }
        .floating-iframe { width: 100%; height: 100%; border: none; opacity: 0; transition: opacity 0.3s; display: block; vertical-align: bottom; background: var(--bg-white); }
        .floating-iframe.loaded { opacity: 1; }

        .immersive-trigger-top { position: fixed; top: 0; left: 0; width: 100%; height: 8px; z-index: 2002; display: none; }
        .immersive-trigger-left { position: fixed; top: 0; left: 0; width: 8px; height: 100%; z-index: 2002; display: none; }
        body.immersive-mode .immersive-trigger-top, body.immersive-mode .immersive-trigger-left { display: block; }
        body.immersive-mode .top-nav { transform: translateY(-100%); box-shadow: 0 4px 20px rgba(0,0,0,0.1); z-index: 2003; }
        body.immersive-mode .sidebar { transform: translateX(-100%); box-shadow: 4px 0 20px rgba(0,0,0,0.1); z-index: 2003; }
        body.immersive-mode .content { top: 0; left: 0 !important; width: 100%; height: 100%; padding: 0; z-index: 500; }
        body.immersive-mode .content-wrapper { border-radius: 0; border: none; }
        body.immersive-mode .immersive-trigger-top:hover ~ .top-nav, body.immersive-mode .top-nav:hover { transform: translateY(0); }
        body.immersive-mode .immersive-trigger-left:hover ~ .sidebar, body.immersive-mode .sidebar:hover { transform: translateX(0); }

        .radio-toggle-btn { position: fixed; bottom: 30px; right: 30px; width: 44px; height: 44px; border-radius: 50%; background: var(--primary-color); color: white; box-shadow: 0 8px 20px rgba(59, 130, 246, 0.4); display: flex; align-items: center; justify-content: center; cursor: pointer; z-index: 2100; transition: background 0.3s, transform 0.2s; border: none; font-size: 18px; touch-action: none; user-select: none; }
        .radio-toggle-btn:hover { background: var(--primary-dark); }
        .radio-toggle-btn:active { transform: scale(0.95); }
        .radio-toggle-btn.draggable-active { transform: scale(1.15) !important; background: #eab308; box-shadow: 0 0 15px rgba(234, 179, 8, 0.6); transition: transform 0.2s cubic-bezier(0.18, 0.89, 0.32, 1.28), background 0.2s; cursor: grabbing; }
        .radio-player-container { width: 260px; height: 420px; position: fixed; bottom: 85px; right: 20px; background: transparent !important; border: none !important; box-shadow: none !important; z-index: 2099; overflow: visible; transform-origin: bottom right; visibility: hidden; transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1), visibility 0s linear 0.4s; opacity: 0; pointer-events: none; transform: scale(0.8) translateY(20px); }
        .radio-player-container.show { opacity: 1; pointer-events: auto; transform: scale(1) translateY(0); visibility: visible; transition-delay: 0s; }
        .radio-iframe { width: 100%; height: 100%; border: none; background: transparent !important; color-scheme: normal; }

        @media (max-width: 992px) {
            :root { --header-height: 56px; }
            .pc-toggle, .user-pill, .logo { display: none; }
            .hamburger { display: flex; margin-right: 0; }
            .mobile-logo { display: flex; }
            .immersive-switch-wrapper { display: none; }
            .tool-icon-btn { margin-right: 12px; }
            .sidebar { transform: translateX(-100%); width: 260px; box-shadow: none; padding-top: 0; border-right: none; }
            .sidebar.show { transform: translateX(0); box-shadow: 20px 0 50px rgba(0,0,0,0.15); }
            .sidebar.collapsed { width: 260px; }
            .sidebar.collapsed .menu-item { justify-content: flex-start; padding: 10px 14px; margin: 0 0 2px 0; }
            .sidebar.collapsed .menu-item span, .sidebar.collapsed .menu-item .blank-icon { display: inline; }
            .sidebar.collapsed .menu-item i { margin-right: 0; font-size: 16px; width: 20px; text-align: center; }
            .sidebar.collapsed .menu-group-header { justify-content: space-between; padding: 8px 20px; height: auto; }
            .sidebar.collapsed .menu-group-header span, .sidebar.collapsed .menu-group-header .toggle { display: block; }
            .sidebar.collapsed .menu-group-header::after { display: none; }
            .content { left: 0; top: var(--header-height); padding: 0 4px 4px 4px; }
            .content.collapsed { left: 0; }
            .top-nav { padding: 0 10px; justify-content: flex-start; }
            .top-menu { margin: 0 10px; flex: 1; }
            .top-menu-item span { display: none; }
            .top-menu-item { padding: 8px 12px; font-size: 16px; justify-content: center; }
            .floating-window, .floating-overlay { display: none !important; }
            .radio-toggle-btn { bottom: 60px; right: 20px; }
            .radio-player-container { bottom: 135px; right: 10px; max-width: 95vw; }
        }

        .sidebar-overlay { display: none; position: fixed; inset: 0; top: 0; background: rgba(0, 0, 0, 0.4); backdrop-filter: blur(4px); z-index: 998; will-change: opacity; animation: fadeInOverlay 0.2s ease; }
        .sidebar-overlay.show { display: block; }