:root {
            --primary: #2563eb;
            --primary-light: #eff6ff;
            --bg-light: #f8fafc;
            --white: #ffffff;
            --text-dark: #0f172a;
            --text-grey: #64748b;
            --border: #e2e8f0;
            --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
        }
        body.dark-mode {
            --bg-light: #0f172a;
            --white: #1e293b;
            --text-dark: #f8fafc; /* Crisp white for standard and bold text visibility */
            --text-grey: #94a3b8;
            --border: #334155;
            background-color: #020617 !important;
        }

        /* --- DARK MODE CORRECTIONS --- */
        body.dark-mode .app-header {
            background: var(--white);
            border-color: var(--border);
        }

        body.dark-mode .back-btn,
        body.dark-mode .header-title {
            color: var(--text-dark);
        }

        /* Inverts the background placeholder container for icons */
        body.dark-mode .exam-box .bg-light {
            background-color: #0f172a !important; 
        }

        body.dark-mode .exam-box h3 {
            color: var(--text-dark);
        }

        body.dark-mode .bottom-nav {
            background: var(--white);
            border-top-color: var(--border);
        }

        

        body {
            font-family: 'Inter', sans-serif;
            background-color: var(--bg-light);
            color: var(--text-dark);
            margin: 0;
            padding-bottom: 80px;
        }

        /* --- APP TOP BAR --- */
        .app-header {
            background: var(--white);
            padding: 15px 20px;
            display: flex;
            align-items: center;
            gap: 15px;
            position: sticky;
            top: 0;
            z-index: 1000;
            box-shadow: var(--shadow-sm);
            border-bottom: 1px solid var(--border);
        }

        .back-btn {
            background: none; border: none; font-size: 1.2rem;
            color: var(--text-dark); cursor: pointer;
            padding: 0; display: flex; align-items: center;
        }

        .header-title {
            font-weight: 800; font-size: 1.15rem; margin: 0;
            flex-grow: 1;
        }

        /* --- VIEW CONTAINERS --- */
        .view-screen { display: none; padding: 20px; animation: slideIn 0.3s ease-out; }
        .view-screen.active { display: block; }

        @keyframes slideIn {
            from { opacity: 0; transform: translateX(15px); }
            to { opacity: 1; transform: translateX(0); }
        }

        /* --- GRID & BOXES --- */
        .category-grid {
            display: grid; grid-template-columns: 1fr; gap: 15px;
        }

        @media (min-width: 700px) {
            .category-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            /* Odd item count: last card stays in one column, leaving a gap */
            .category-grid > *:last-child:nth-child(odd) {
                grid-column: span 1;
            }
        }

        .exam-box {
            background: var(--white);
            border-radius: 20px;
            padding: 20px;
            display: flex;
            align-items: center;
            text-decoration: none;
            color: inherit;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            transition: transform 0.2s;
        }

        .exam-box:active { transform: scale(0.97); }

        .exam-logo-img {
            width: 50px; height: 50px;
            border-radius: 12px;
            object-fit: cover;
            margin-right: 15px;
            background: #fff;
        }

        .exam-info h3 { font-size: 1rem; font-weight: 800; margin: 0; }
        .exam-info p { font-size: 0.75rem; color: var(--text-grey); margin: 3px 0 0; line-height: 1.3; }

        .chevron { margin-left: auto; color: var(--text-grey); font-size: 0.9rem; }

        /* Coming Soon Badge */
        .badge-soon {
            font-size: 0.65rem; background: #fee2e2; color: #ef4444;
            padding: 2px 8px; border-radius: 50px; font-weight: 700;
            margin-left: 10px;
        }

        /* --- BOTTOM NAV --- */
        .bottom-nav {
            position: fixed; bottom: 0; left: 0; width: 100%;
            background: var(--white); display: flex; justify-content: space-around;
            padding: 12px 0; border-top: 1px solid var(--border); z-index: 1000;
        }
        .nav-item {
            text-align: center; color: var(--text-grey); text-decoration: none;
            font-size: 0.7rem; font-weight: 600; flex: 1;
        }
        .nav-item i { display: block; font-size: 1.3rem; margin-bottom: 4px; }
        .nav-item.active { color: var(--primary); }

        /* --- SKELETON LOADING --- */
        .skeleton-exam-box {
            background: var(--white);
            border-radius: 20px;
            padding: 20px;
            display: flex;
            align-items: center;
            gap: 15px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
        }
        .skeleton-exam-box .skeleton-line {
            background: var(--border);
            border-radius: 6px;
            animation: skeleton-blink 1.2s ease-in-out infinite;
        }
        .skeleton-exam-box .skeleton-logo { width: 50px; height: 50px; border-radius: 12px; flex-shrink: 0; }
        .skeleton-exam-box .skeleton-title { height: 14px; width: 55%; margin-bottom: 8px; }
        .skeleton-exam-box .skeleton-sub { height: 11px; width: 75%; }
        @keyframes skeleton-blink {
            0%, 100% { opacity: 0.4; }
            50% { opacity: 1; }
        }