:root {
            --primary-color: #000;   
            --primary-hover: #333;   
            --success-color: #10b981;   
            --danger-color: #e11d48;    
            --bg-color: #f5f5f5;        
            --card-bg: #ffffff;         
            --accent-bg: #f0f0f0;       
            --text-main: #333;       
            --text-dim: #666;        
            --border-color: #e5e5e5;    
            --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.08); 
            --radius: 24px;             
        }

        .box {
            background: var(--card-bg);
            border: 3px solid var(--border-color);
            border-radius: var(--radius);
            padding: 25px;
            width: 100%;
            max-width: 500px;
            box-shadow: var(--shadow);
            margin-bottom: 25px;
            box-sizing: border-box;
            transition: all 0.3s ease;
        }

        h1, h2, h3 {
            color: var(--primary-color);
            margin-top: 0;
            text-align: center;
            letter-spacing: 1px;
            font-weight: 800;
            text-shadow: none;
        }

        #intro-box { background: var(--accent-bg); border: none; border-left: 5px solid var(--primary-color); }
        .intro-text { font-size: 0.95rem; line-height: 1.7; color: var(--text-main); font-weight: 500; }

        #punishment-box {
            display: none; background: #f5f5f5; border: 3px dashed var(--danger-color);
            animation: pulseBorderCute 2s infinite ease-in-out;
        }
        @keyframes pulseBorderCute {
            0% { box-shadow: 0 0 5px rgba(225, 29, 72, 0.1); }
            50% { box-shadow: 0 0 20px rgba(225, 29, 72, 0.3); }
            100% { box-shadow: 0 0 5px rgba(225, 29, 72, 0.1); }
        }
        #punishment-box h3 { color: var(--danger-color); }

        .btn-group { display: flex; flex-direction: column; gap: 15px; }

        button {
            background: linear-gradient(145deg, #fff, #f0f0f0);
            color: var(--primary-color);
            border: 3px solid var(--border-color);
            padding: 15px 20px;
            border-radius: 12px;
            font-size: 1.05rem;
            font-weight: 800;
            cursor: pointer;
            transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
            width: 100%;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.06);
        }
        /* button:hover { background: linear-gradient(145deg, var(--primary-color), var(--primary-hover)); color: white; border-color: var(--primary-hover); transform: scale(1.02); } */
        button:disabled { background: #f3f4f6; border-color: #e5e7eb; color: #9ca3af; cursor: not-allowed; box-shadow: none; transform: none; background-image: none; }
        
        .flashcard-btn { background: linear-gradient(145deg, #fff, #e0e0e0); color: #333; border-color: #ccc; }
        .flashcard-btn:hover { background: linear-gradient(145deg, #333, #000); border-color: #000; }

        .sm-task-card {
            background: #ffffff; border: 2px solid var(--border-color); border-left-width: 6px;
            padding: 18px; margin-bottom: 15px; border-radius: 16px; animation: fadeIn 0.5s ease;
            position: relative; box-shadow: 0 2px 5px rgba(0, 0, 0, 0.04);
        }
        .task-title { font-weight: 800; color: var(--primary-color); margin-bottom: 8px; display: block; font-size: 1rem; }
        .task-desc { font-size: 0.85rem; color: var(--text-dim); margin-bottom: 12px; }
        .task-result { font-size: 1.15rem; font-weight: 800; color: var(--text-main); padding: 12px 0; border-top: 2px dashed var(--border-color); margin-top: 5px; }

        .task-actions { display: flex; gap: 12px; /*margin-top: 15px;*/ padding-top: 15px; border-top: 2px solid #fce7f3; }
        .action-btn { padding: 10px; font-size: 0.9rem; border-width: 2px; border-radius: 12px; flex: 1; background: white; }
        .btn-complete { border-color: var(--success-color); color: var(--success-color); }
        .btn-complete:hover { background: var(--success-color); color: white; }
        .btn-fail { border-color: var(--danger-color); color: var(--danger-color); }
        .btn-fail:hover { background: var(--danger-color); color: white; }

        .status-badge { display: inline-block; padding: 6px 12px; border-radius: 50px; font-size: 0.85rem; font-weight: 800; margin-top: 12px; width: 100%; text-align: center; box-sizing: border-box; }
        .status-success { background: #f0f0f0; color: #2e7d32; border: 2px solid #999; }
        .status-failed { background: #f0f0f0; color: #b91c1c; border: 2px solid #999; }

        @keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

        /* 统计区域 */
        .stats-container {
            display: flex; justify-content: space-around; margin-bottom: 20px;
            background: #fafafa; padding: 15px; border-radius: 20px; border: 2px dashed var(--border-color);
        }
        .stat-item { text-align: center; display: flex; flex-direction: column; align-items: center; }
        .stat-num { font-size: 1.8rem; font-weight: 900; color: var(--primary-color); line-height: 1; margin-bottom: 5px; }
        .stat-label { font-size: 0.8rem; color: var(--text-dim); font-weight: 600; }

        /* 日历样式 */
        .calendar-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 15px; color: var(--primary-color); font-weight: 800; font-size: 1.1rem; }
        .cal-nav-btn { background: none; border: none; color: var(--primary-color); font-size: 1.2rem; cursor: pointer; padding: 5px 10px; width: auto; box-shadow: none; }
        .cal-nav-btn:hover { background: var(--accent-bg); border-radius: 10px; transform: none; }
        .calendar-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 5px; text-align: center; }
        .cal-day-name { font-size: 0.8rem; color: var(--text-dim); font-weight: bold; padding-bottom: 5px; }
        .cal-day { aspect-ratio: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; border-radius: 10px; font-size: 0.9rem; color: var(--text-main); position: relative; background: #fff; border: 1px solid transparent; transition: all 0.2s; }
        .cal-day.empty { background: none; }
        .cal-day.today { border: 2px solid var(--primary-color); background: #fafafa; font-weight: bold; }
        .cal-status-icon { font-size: 0.9rem; margin-top: 2px; line-height: 1; }
        .cal-legend { display: flex; justify-content: center; gap: 15px; margin-top: 15px; flex-wrap: wrap; }
        .legend-item { font-size: 0.75rem; color: var(--text-dim); display: flex; align-items: center; gap: 4px; }

        /* Toast & Modal */
        #toast-container { position: fixed; top: 30px; left: 50%; transform: translateX(-50%); z-index: 2000; display: flex; flex-direction: column; gap: 15px; pointer-events: none; width: 90%; max-width: 420px; align-items: center; }
        .toast { background: #ffffff; color: var(--text-main); padding: 15px 25px; border-radius: 20px; border: 3px solid var(--primary-color); box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1); font-size: 1rem; font-weight: 600; animation: slideDownCute 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275); pointer-events: auto; display: flex; align-items: center; width: fit-content; max-width: 100%; }
        .toast.success { border-color: var(--success-color); background: #f5f5f5; color: #2e7d32; }
        .toast.error { border-color: var(--danger-color); background: #f5f5f5; color: #b91c1c; }
        .toast.info { border-color: var(--primary-color); background: #f5f5f5; color: var(--text-main); }
        @keyframes slideDownCute { from { transform: translateY(-40px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

        #modal-overlay { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(255, 255, 255, 0.6); backdrop-filter: blur(8px); z-index: 3000; display: flex; justify-content: center; align-items: center; opacity: 0; pointer-events: none; transition: opacity 0.3s ease; }
        #modal-overlay.active { opacity: 1; pointer-events: auto; }
        .custom-modal { background: #ffffff; border: 4px solid var(--primary-color); width: 85%; max-width: 420px; padding: 30px; border-radius: 30px; box-shadow: 0 20px 40px rgba(0, 0, 0, 0.12); text-align: center; transform: scale(0.9); transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275); max-height: 90vh; overflow-y: auto; }
        /* #modal-overlay.active .custom-modal { transform: scale(1); } */
        .modal-title { font-size: 1.6rem; color: var(--primary-color); margin-bottom: 18px; font-weight: 800; }
        .modal-body { font-size: 1.05rem; color: var(--text-main); margin-bottom: 18px; line-height: 1.6; white-space: pre-wrap; font-weight: 500; }
        .modal-actions { display: flex; justify-content: center; gap: 20px; }
        .modal-btn { padding: 12px 30px; width: auto; min-width: 120px; border-radius: 50px; font-size: 1rem; }
        .modal-btn.secondary { background: transparent; border-color: var(--border-color); color: var(--text-dim); box-shadow: none; }

        /* Flashcard Template (优化版) */
        #flashcard-template { 
            position: fixed; left: -9999px; top: 0; width: 450px; background: #fff; padding: 30px; 
            border-radius: var(--radius); overflow: hidden; 
            background-image: radial-gradient(#fbcfe8 1px, transparent 1px); background-size: 20px 20px; background-color: #fdf2f8; 
            font-family: 'Microsoft YaHei', sans-serif; color: var(--text-main); box-sizing: border-box; border: 10px solid #fce7f3; 
        }
        .fc-header { text-align: center; border-bottom: 3px dashed var(--primary-color); padding-bottom: 15px; margin-bottom: 20px; }
        .fc-title { color: var(--primary-color); font-size: 1.8rem; font-weight: 900; margin: 0; }
        .fc-date { color: var(--text-dim); font-size: 1rem; margin-top: 5px; }
        
        /* 闪卡上的统计数据样式 */
        .fc-stats {
            margin-top: 10px; font-size: 0.95rem; color: var(--text-dim); font-weight: 800;
            background: #fafafa; display: inline-block; padding: 5px 15px; border-radius: 20px; border: 2px solid var(--border-color);
        }

        .fc-section-title { font-size: 1.1rem; color: var(--primary-color); font-weight: bold; margin-bottom: 10px; border-left: 5px solid var(--primary-color); padding-left: 10px; background: #fff; line-height: 1.5; }
        .fc-item { background: #fff; border: 2px solid var(--border-color); border-radius: 12px; padding: 12px; margin-bottom: 10px; position: relative; }
        .fc-item-title { font-weight: bold; color: var(--text-dim); font-size: 0.9rem; }
        .fc-item-result { font-weight: bold; font-size: 1.1rem; margin-top: 5px; color: var(--text-main); }
        .fc-status { position: absolute; right: 10px; top: 10px; font-size: 1.2rem; }
        .fc-footer { text-align: center; margin-top: 30px; font-size: 0.8rem; color: #ccc; }

        .footer-actions { text-align: center; }
        .text-btn { background:none;border: none; color: var(--text-dim); font-size: 0.9rem; cursor: pointer; box-shadow: none; border-radius: 6px; }

        /* Footer & Buttons */
        .container-footer { text-align: center; margin-bottom: 40px; }
        .footer-actions-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 5px;
            margin-top: 15px;
            padding: 0 15px;
        }
        .text-btn { 
            background: white; border: 2px solid var(--border-color); 
            color: var(--text-dim); font-size: 0.9rem; cursor: pointer; 
            padding: 10px 15px; border-radius: 10px; width: 100%;
            transition: all 0.2s;
        }
        .text-btn:hover { background: var(--accent-bg); transform: translateY(-2px); }
        
        /* 危险按钮样式 */
        .text-btn.danger {
            border-color: #ccc; color: #e11d48;
            grid-column: span 2; /* 独占一行 */
            margin-top: 10px;
        }
        .text-btn.danger:hover { background: #f5f5f5; }