:root {
    /* Premium HSL Color Palette */
    --primary-hue: 224;
    --primary: hsl(var(--primary-hue), 76%, 48%);
    --primary-hover: hsl(var(--primary-hue), 80%, 40%);
    --primary-light: hsl(var(--primary-hue), 90%, 96%);
    
    --secondary-hue: 217;
    --secondary: hsl(var(--secondary-hue), 91%, 60%);
    --secondary-hover: hsl(var(--secondary-hue), 92%, 52%);
    
    --accent-hue: 142;
    --accent: hsl(var(--accent-hue), 71%, 45%);
    --accent-hover: hsl(var(--accent-hue), 72%, 37%);
    --accent-light: hsl(var(--accent-hue), 70%, 95%);
    
    --danger-hue: 350;
    --danger: hsl(var(--danger-hue), 89%, 60%);
    --danger-hover: hsl(var(--danger-hue), 90%, 50%);
    --danger-light: hsl(var(--danger-hue), 90%, 96%);
    
    --warning-hue: 38;
    --warning: hsl(var(--warning-hue), 92%, 50%);
    --warning-light: hsl(var(--warning-hue), 90%, 96%);

    --bg-main: radial-gradient(circle at 10% 20%, rgb(240, 249, 255) 0%, rgb(224, 242, 254) 90.2%);
    --bg-card: rgba(255, 255, 255, 0.8);
    --bg-glass: rgba(255, 255, 255, 0.45);
    
    --text-main: #0f172a;
    --text-muted: #475569;
    --text-light: #94a3b8;
    
    --border: rgba(255, 255, 255, 0.5);
    --border-dark: rgba(0, 0, 0, 0.08);
    
    /* Shadows & Radii */
    --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.03);
    --shadow: 0 8px 30px rgba(15, 23, 42, 0.04), 0 1px 3px rgba(15, 23, 42, 0.02);
    --shadow-lg: 0 20px 40px rgba(15, 23, 42, 0.07), 0 1px 5px rgba(15, 23, 42, 0.03);
    --shadow-inset: inset 0 2px 4px rgba(0, 0, 0, 0.02);
    
    --radius-sm: 8px;
    --radius: 16px;
    --radius-lg: 24px;
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Base resets & fonts */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

body {
    background: var(--bg-main);
    color: var(--text-main);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

/* Glassmorphism utility */
.glass-panel {
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.glass-panel:hover {
    box-shadow: var(--shadow-lg);
    border-color: rgba(255, 255, 255, 0.8);
}

/* Modern Card */
.card {
    background: white;
    border-radius: var(--radius);
    border: 1px solid var(--border-dark);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

/* Typography elements */
h1, h2, h3, h4, h5, h6 {
    font-family: 'Outfit', sans-serif;
    color: #0f172a;
    font-weight: 700;
    letter-spacing: -0.01em;
}

/* Forms & Inputs */
.form-group {
    margin-bottom: 1.5rem;
    text-align: left;
}

.form-label {
    display: block;
    font-size: 0.85rem;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.form-input-modern {
    width: 100%;
    padding: 0.875rem 1.15rem;
    border: 1px solid var(--border-dark);
    background: rgba(255, 255, 255, 0.85);
    border-radius: 10px;
    font-size: 1rem;
    font-family: 'Inter', sans-serif;
    color: #0f172a;
    transition: var(--transition);
    box-shadow: var(--shadow-inset);
}

.form-input-modern:focus {
    outline: none;
    border-color: var(--secondary);
    background: #ffffff;
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.12), var(--shadow-inset);
}

/* Custom modern buttons */
.btn-modern {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background: linear-gradient(135deg, var(--primary) 0%, hsl(var(--primary-hue), 85%, 42%) 100%);
    color: white;
    padding: 0.875rem 1.75rem;
    border-radius: 10px;
    font-weight: 700;
    font-size: 0.95rem;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(30, 64, 175, 0.2);
    text-decoration: none;
    text-align: center;
}

.btn-modern:hover {
    background: linear-gradient(135deg, hsl(var(--primary-hue), 85%, 42%) 0%, var(--primary) 100%);
    box-shadow: 0 6px 18px rgba(30, 64, 175, 0.3);
    transform: translateY(-1px);
}

.btn-modern:active {
    transform: translateY(1px);
}

.btn-modern:disabled {
    background: #cbd5e1 !important;
    color: #94a3b8 !important;
    box-shadow: none !important;
    cursor: not-allowed;
    transform: none !important;
}

.btn-accent {
    background: linear-gradient(135deg, var(--accent) 0%, hsl(var(--accent-hue), 72%, 37%) 100%);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.2);
}
.btn-accent:hover {
    background: linear-gradient(135deg, hsl(var(--accent-hue), 72%, 37%) 0%, var(--accent) 100%);
    box-shadow: 0 6px 18px rgba(16, 185, 129, 0.3);
}

.btn-danger {
    background: linear-gradient(135deg, var(--danger) 0%, hsl(var(--danger-hue), 85%, 45%) 100%);
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.2);
}
.btn-danger:hover {
    background: linear-gradient(135deg, hsl(var(--danger-hue), 85%, 45%) 0%, var(--danger) 100%);
    box-shadow: 0 6px 18px rgba(239, 68, 68, 0.3);
}

/* Animations classes */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

.animate-fade {
    animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

/* Modern tables styling */
.table-responsive {
    overflow-x: auto;
    border-radius: 12px;
    border: 1px solid var(--border-dark);
}

.progress-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.92rem;
    background: white;
}

.progress-table th {
    background: rgba(15, 23, 42, 0.02);
    padding: 1rem 1.25rem;
    color: var(--text-muted);
    font-weight: 700;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid var(--border-dark);
}

.progress-table td {
    padding: 1rem 1.25rem;
    border-bottom: 1px solid rgba(15, 23, 42, 0.04);
    color: #334155;
    transition: var(--transition);
}

.progress-table tr:hover td {
    background: rgba(15, 23, 42, 0.01);
}

/* Custom Scrollbars */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.02);
}
::-webkit-scrollbar-thumb {
    background: rgba(0, 0, 0, 0.15);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: rgba(0, 0, 0, 0.25);
}

/* iOS-style toggle switches */
.ios-switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}

.ios-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.ios-switch-slider {
    position: absolute;
    cursor: pointer;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: #cbd5e1;
    transition: .3s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: 34px;
}

.ios-switch-slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: .3s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: 50%;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

input:checked + .ios-switch-slider {
    background-color: var(--accent);
}

input:checked + .ios-switch-slider:before {
    transform: translateX(20px);
}

/* ======================================================== */
/* EXAM PLAYER UNIQUE STYLES (SPLIT SCREEN LAYOUT)          */
/* ======================================================== */
.exam-layout-split {
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 1.5rem;
    align-items: start;
    height: calc(100vh - 75px);
    overflow: hidden;
    padding: 1rem 1.5rem;
}

.exam-sidebar-left {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    height: 100%;
    overflow-y: auto;
}

.exam-content-right {
    background: white;
    border: 1px solid var(--border-dark);
    border-radius: var(--radius);
    padding: 2rem 2.5rem;
    box-shadow: var(--shadow);
    height: 100%;
    overflow-y: auto;
}

.question-nav-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.5rem;
    margin: 1.25rem 0;
}

.q-nav-btn {
    aspect-ratio: 1;
    border-radius: 10px;
    border: 1px solid rgba(0, 0, 0, 0.08);
    background: #f8fafc;
    color: #475569;
    font-size: 0.9rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.q-nav-btn:hover {
    background: #e2e8f0;
    color: #0f172a;
    transform: scale(1.05);
}

.q-nav-btn.answered {
    background: var(--accent-light);
    color: var(--accent);
    border-color: rgba(16, 185, 129, 0.3);
}

.q-nav-btn.flagged {
    background: var(--warning-light);
    color: var(--warning);
    border-color: rgba(245, 158, 11, 0.3);
}

.q-nav-btn.flagged::after {
    content: '🚩';
    position: absolute;
    top: -4px;
    right: -4px;
    font-size: 0.65rem;
}

.q-nav-btn.active {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white !important;
    border-color: transparent;
    box-shadow: 0 4px 10px rgba(30, 64, 175, 0.25);
    transform: scale(1.05);
}

.q-nav-btn.correct-ans {
    background: rgba(16, 185, 129, 0.15) !important;
    color: #047857 !important;
    border: 2px solid #10b981 !important;
}

.q-nav-btn.wrong-ans {
    background: rgba(239, 68, 68, 0.15) !important;
    color: #b91c1c !important;
    border: 2px solid #ef4444 !important;
}

/* Math symbols visual */
.MathJax {
    font-size: 1.05em !important;
    color: #1e293b;
}

/* Inline choice formatting */
.choice-wrapper {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.875rem 1.25rem;
    border-radius: 10px;
    border: 1px solid var(--border-dark);
    margin-bottom: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
    background: #f8fafc;
}

.choice-wrapper:hover {
    background: #f1f5f9;
    border-color: rgba(30, 64, 175, 0.15);
}

.choice-wrapper.selected {
    background: var(--primary-light);
    border-color: var(--secondary);
    color: var(--primary-hover);
    font-weight: 600;
}

.choice-wrapper.correct-mark {
    background: #f0fdf4 !important;
    border-color: #86efac !important;
    color: #166534 !important;
}

.choice-wrapper.wrong-mark {
    background: #fef2f2 !important;
    border-color: #fca5a5 !important;
    color: #991b1b !important;
}

@media (max-width: 992px) {
    .exam-layout-split {
        grid-template-columns: 1fr;
        height: auto;
        overflow: visible;
    }
    .exam-sidebar-left, .exam-content-right {
        height: auto;
        overflow: visible;
    }
}