:root {
    --primary: #4361ee;
    --primary-dark: #3a56d4;
    --success: #2ec4b6;
    --danger: #e63946;
    --warning: #f4a261;
    --bg: #f8f9fa;
    --card-radius: 16px;
}

* {
    -webkit-tap-highlight-color: transparent;
}

body {
    background: var(--bg);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

.navbar {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%) !important;
    padding: 12px 0;
    box-shadow: 0 2px 12px rgba(0,0,0,0.15);
}

/* Cards */
.card {
    border: none;
    border-radius: var(--card-radius);
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
    transition: transform 0.2s, box-shadow 0.2s;
    overflow: hidden;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}

.card-img-top {
    height: 180px;
    object-fit: cover;
}

/* Lesson cards */
.lesson-card {
    cursor: pointer;
    position: relative;
}

.lesson-card .badge-progress {
    position: absolute;
    top: 12px;
    right: 12px;
    font-size: 0.85rem;
    padding: 6px 12px;
    border-radius: 20px;
}

/* Quiz UI */
.quiz-container {
    max-width: 700px;
    margin: 0 auto;
}

.quiz-progress {
    height: 8px;
    border-radius: 4px;
    background: #e9ecef;
    overflow: hidden;
    margin-bottom: 24px;
}

.quiz-progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--success));
    border-radius: 4px;
    transition: width 0.4s ease;
}

.question-card {
    border-radius: var(--card-radius);
    padding: 28px;
    background: white;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
}

.question-text {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 20px;
    line-height: 1.5;
}

.question-image {
    max-width: 100%;
    max-height: 300px;
    object-fit: contain;
    border-radius: 12px;
    margin-bottom: 20px;
}

/* Answer buttons */
.answer-btn {
    display: block;
    width: 100%;
    padding: 16px 20px;
    margin-bottom: 12px;
    border: 2px solid #e9ecef;
    border-radius: 12px;
    background: white;
    font-size: 1.05rem;
    text-align: left;
    cursor: pointer;
    transition: all 0.2s;
    color: #333;
}

.answer-btn:hover {
    border-color: var(--primary);
    background: #f0f3ff;
    transform: scale(1.01);
}

.answer-btn:active {
    transform: scale(0.98);
}

.answer-btn.selected {
    border-color: var(--primary);
    background: #e8edff;
}

/* Feedback */
.feedback-overlay {
    position: fixed;
    inset: 0;
    z-index: 1050;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0,0,0,0.5);
    animation: fadeIn 0.2s;
}

.feedback-card {
    background: white;
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    max-width: 450px;
    width: 90%;
    animation: popIn 0.3s;
}

.feedback-icon {
    font-size: 4rem;
    margin-bottom: 16px;
}

.feedback-correct .feedback-icon { color: var(--success); }
.feedback-wrong .feedback-icon { color: var(--danger); }

@keyframes fadeIn { from { opacity:0 } to { opacity:1 } }
@keyframes popIn { from { transform:scale(0.8); opacity:0 } to { transform:scale(1); opacity:1 } }

/* Result page */
.result-circle {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 0 auto 24px;
    font-size: 2.5rem;
    font-weight: 700;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

.result-circle.excellent { background: linear-gradient(135deg, #d4edda, #c3e6cb); color: #155724; }
.result-circle.good { background: linear-gradient(135deg, #cce5ff, #b8daff); color: #004085; }
.result-circle.average { background: linear-gradient(135deg, #fff3cd, #ffeeba); color: #856404; }
.result-circle.poor { background: linear-gradient(135deg, #f8d7da, #f5c6cb); color: #721c24; }

/* Stats */
.stat-card {
    text-align: center;
    padding: 20px;
}

.stat-card .stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
}

.stat-card .stat-label {
    color: #6c757d;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Auth pages */
.auth-container {
    max-width: 440px;
    margin: 40px auto;
}

.auth-card {
    border-radius: var(--card-radius);
    padding: 40px;
    background: white;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
}

.auth-card .form-control {
    padding: 12px 16px;
    border-radius: 10px;
    font-size: 1rem;
}

.auth-card .btn-primary {
    padding: 12px;
    border-radius: 10px;
    font-size: 1.05rem;
    font-weight: 600;
}

/* Admin */
.admin-table {
    border-radius: var(--card-radius);
    overflow: hidden;
}

.btn-icon {
    width: 40px;
    height: 40px;
    padding: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
}

/* iPad optimizations */
@media (min-width: 768px) and (max-width: 1024px) {
    .container { max-width: 90%; }
    .answer-btn { padding: 20px 24px; font-size: 1.1rem; }
    .question-text { font-size: 1.4rem; }
}

@media (max-width: 576px) {
    .auth-card { padding: 24px; }
    .question-card { padding: 20px; }
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #adb5bd;
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 16px;
}

/* Lesson grid */
.lesson-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

/* Default card image placeholder */
.card-img-placeholder {
    height: 180px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 3rem;
}

/* Question list in admin */
.question-item {
    background: white;
    border-radius: 12px;
    padding: 16px 20px;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 16px;
    box-shadow: 0 1px 6px rgba(0,0,0,0.06);
}

.question-item .q-number {
    background: var(--primary);
    color: white;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.question-item .q-text {
    flex: 1;
    font-weight: 500;
}

.question-item .q-type {
    font-size: 0.8rem;
    color: #6c757d;
}