* {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
        }
        .sidebar-active {
            background: linear-gradient(90deg, rgba(30, 64, 175, 0.1) 0%, rgba(30, 64, 175, 0) 100%);
            border-left: 3px solid #1E40AF;
            color: #1E40AF;
        }
        .course-card:hover {
            transform: translateY(-4px);
            box-shadow: 0 20px 40px -12px rgba(0, 0, 0, 0.15);
        }
        .stat-card:hover {
            transform: translateY(-2px);
            box-shadow: 0 12px 24px -8px rgba(0, 0, 0, 0.1);
        }
        .notification-badge {
            animation: pulse 2s infinite;
        }
        @keyframes pulse {
            0%, 100% { opacity: 1; }
            50% { opacity: 0.5; }
        }
        .mobile-sidebar {
            transform: translateX(-100%);
            transition: transform 0.3s ease;
        }
        .mobile-sidebar.open {
            transform: translateX(0);
        }
        .progress-ring {
            transform: rotate(-90deg);
        }
        .todo-item:hover .todo-delete {
            opacity: 1;
        }
        .todo-delete {
            opacity: 0;
            transition: opacity 0.2s;
        }
        .calendar-day:hover {
            background: #f1f5f9;
        }
        .calendar-day.active {
            background: #1e40af;
            color: white;
        }
        .calendar-day.has-task::after {
            content: '';
            position: absolute;
            bottom: 4px;
            left: 50%;
            transform: translateX(-50%);
            width: 6px;
            height: 6px;
            background: #3b82f6;
            border-radius: 50%;
        }
        .calendar-day.active.has-task::after {
            background: white;
        }