/* 基础样式，避免无样式内容闪烁 */
        body {
            margin: 0;
            padding: 0;
            font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            overflow-x: hidden;
        }
        
        /* 页面加载动画 */
        .page-loader {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            z-index: 9999;
            transition: opacity 0.5s ease, visibility 0.5s ease;
        }
        
        .page-loader.loaded {
            opacity: 0;
            visibility: hidden;
        }
        
        .loader-content {
            text-align: center;
            color: white;
        }
        
        .loader-spinner {
            width: 48px;
            height: 48px;
            border: 3px solid rgba(255, 255, 255, 0.1);
            border-top: 3px solid rgba(255, 255, 255, 0.8);
            border-right: 3px solid rgba(255, 255, 255, 0.6);
            border-radius: 50%;
            animation: spin 1.2s ease-in-out infinite;
            margin: 0 auto 24px;
            box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
        }
        
        .loader-text {
            font-size: 18px;
            font-weight: 600;
            margin-bottom: 8px;
        }
        
        .loader-subtitle {
            font-size: 14px;
            opacity: 0.8;
            margin-bottom: 20px;
        }
        
        .loader-progress {
            width: 200px;
            height: 2px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 1px;
            overflow: hidden;
            margin: 0 auto;
        }
        
        .loader-progress-bar {
            height: 100%;
            background: linear-gradient(90deg, rgba(255,255,255,0.6), rgba(255,255,255,1), rgba(255,255,255,0.6));
            width: 0%;
            animation: loadProgress 2s ease-in-out infinite;
        }
        
        @keyframes loadProgress {
            0% { width: 0%; }
            50% { width: 70%; }
            100% { width: 100%; }
        }
        
        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
        
        /* 渐进式显示动画 */
        .animate-fade-in {
            animation: fadeIn 0.5s ease-in-out;
        }
        
        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(10px) scale(0.95);
            }
            to {
                opacity: 1;
                transform: translateY(0) scale(1);
            }
        }
        
        /* 隐藏主内容直到加载完成 */
        .main-content {
            opacity: 0;
            transition: opacity 0.5s ease;
        }
        
        .main-content.loaded {
            opacity: 1;
        }
        
        /* 字体图标优化 */
        .fas, .fab {
            font-display: swap;
        }
        
        /* 屏幕阅读器专用样式 */
        .sr-only {
            position: absolute;
            width: 1px;
            height: 1px;
            padding: 0;
            margin: -1px;
            overflow: hidden;
            clip: rect(0, 0, 0, 0);
            white-space: nowrap;
            border: 0;
        }
        
        .focus\:not-sr-only:focus {
            position: static;
            width: auto;
            height: auto;
            padding: inherit;
            margin: inherit;
            overflow: visible;
            clip: auto;
            white-space: normal;
        }
        
        /* 禁用状态增强样式 */
        .ratio-btn:disabled,
        .edit-ratio-btn:disabled,
        select:disabled {
            position: relative;
            background: #f3f4f6 !important;
            color: #9ca3af !important;
            cursor: not-allowed !important;
            filter: grayscale(0.8) !important;
        }
        
        .ratio-btn:disabled::before,
        .edit-ratio-btn:disabled::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: linear-gradient(45deg, transparent 40%, rgba(239, 68, 68, 0.1) 45%, rgba(239, 68, 68, 0.1) 55%, transparent 60%);
            background-size: 8px 8px;
            pointer-events: none;
            border-radius: inherit;
        }
        
        /* 禁用图标样式 */
        .disabled-indicator {
            animation: disabledPulse 2s infinite ease-in-out;
        }
        
        @keyframes disabledPulse {
            0%, 100% {
                opacity: 0.6;
            }
            50% {
                opacity: 1;
            }
        }
        
        /* 增强的悬浮提示样式 */
        .enhanced-tooltip {
            animation: tooltipFadeIn 0.3s ease-out;
            background: linear-gradient(135deg, #1f2937 0%, #374151 100%) !important;
            border: 1px solid rgba(239, 68, 68, 0.3);
            box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2), 0 0 8px rgba(239, 68, 68, 0.1) !important;
        }
        
        @keyframes tooltipFadeIn {
            from {
                opacity: 0;
                transform: translateX(-50%) translateY(4px);
            }
            to {
                opacity: 1;
                transform: translateX(-50%) translateY(0);
            }
        }

        /* 结果Tab切换样式 */
        .tab-result-btn {
            background: transparent;
            color: rgba(255, 255, 255, 0.7);
            border: none;
            transition: all 0.3s ease;
        }

        .tab-result-btn:hover {
            background: rgba(255, 255, 255, 0.1);
            color: rgba(255, 255, 255, 0.9);
        }

        .tab-result-btn.active {
            background: rgba(255, 255, 255, 0.2);
            color: white;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
        }