/* ============================================
   GEOMETRIC SHAPES EXHIBITION - STYLE.CSS
   Enhanced with Theme System & Multi-Level Support
   ============================================ */

/* ==================== CSS VARIABLES - THEMES ==================== */
:root {
    /* Light Theme (Default) */
    --bg-primary: #f0f4f8;
    --bg-secondary: #ffffff;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --text-primary: #2D3748;
    --text-secondary: #4A5568;
    --text-light: #718096;
    --primary-color: #4A90D9;
    --primary-dark: #2E5C8A;
    --secondary-color: #6C63FF;
    --accent-color: #FF6B6B;
    --success-color: #4ECDC4;
    --warning-color: #FFD93D;
    --card-shadow: 0 4px 12px rgba(0,0,0,0.1);
    --hover-shadow: 0 8px 24px rgba(0,0,0,0.15);
    --border-color: #e2e8f0;
    --formula-bg: #f7fafc;
    --badge-kids: #FF8B6B;
    --badge-student: #6BCBFF;
    --badge-advanced: #8B6BFF;
}

[data-theme="dark"] {
    --bg-primary: #1a202c;
    --bg-secondary: #2D3748;
    --bg-gradient: linear-gradient(135deg, #1a202c 0%, #2D3748 100%);
    --text-primary: #f7fafc;
    --text-secondary: #e2e8f0;
    --text-light: #a0aec0;
    --primary-color: #63B3ED;
    --primary-dark: #4299E1;
    --secondary-color: #9F7AEA;
    --accent-color: #FC8181;
    --success-color: #68D391;
    --warning-color: #F6E05E;
    --card-shadow: 0 4px 12px rgba(0,0,0,0.4);
    --hover-shadow: 0 8px 24px rgba(0,0,0,0.6);
    --border-color: #4a5568;
    --formula-bg: #2D3748;
}

[data-theme="kids"] {
    --bg-primary: #FFF5F5;
    --bg-secondary: #ffffff;
    --bg-gradient: linear-gradient(135deg, #FF9A9E 0%, #FECFEF 100%);
    --text-primary: #553C7B;
    --text-secondary: #6B4C7B;
    --text-light: #9B7B9B;
    --primary-color: #FF6B9D;
    --primary-dark: #FF477E;
    --secondary-color: #A78BFA;
    --accent-color: #FB923C;
    --success-color: #34D399;
    --warning-color: #FBBF24;
    --card-shadow: 0 6px 16px rgba(255,107,157,0.2);
    --hover-shadow: 0 10px 30px rgba(255,107,157,0.3);
    --border-color: #FED7E2;
    --formula-bg: #FAF5FF;
    --badge-kids: #FBB6CE;
    --badge-student: #BAE6FD;
    --badge-advanced: #E9D8FD;
}

[data-theme="professional"] {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-gradient: linear-gradient(135deg, #1e3a5f 0%, #2d5a87 100%);
    --text-primary: #1e293b;
    --text-secondary: #334155;
    --text-light: #64748b;
    --primary-color: #0ea5e9;
    --primary-dark: #0284c7;
    --secondary-color: #6366f1;
    --accent-color: #ef4444;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --card-shadow: 0 2px 8px rgba(0,0,0,0.08);
    --hover-shadow: 0 4px 16px rgba(0,0,0,0.12);
    --border-color: #e2e8f0;
    --formula-bg: #f1f5f9;
}

/* ==================== BASE STYLES ==================== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    min-height: 100vh;
    transition: all 0.3s ease;
}

/* ==================== LANGUAGE SELECTOR ==================== */
.language-selector {
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 1001;
    display: flex;
    align-items: center;
    gap: 10px;
    background: var(--bg-secondary);
    padding: 10px 15px;
    border-radius: 10px;
    box-shadow: var(--hover-shadow);
    border: 2px solid var(--border-color);
}

.language-selector label {
    font-weight: 600;
    color: var(--text-primary);
}

.language-selector select {
    padding: 8px 12px;
    border-radius: 6px;
    border: 2px solid var(--border-color);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.95rem;
    cursor: pointer;
}

/* ==================== THEME SELECTOR ==================== */
.theme-selector {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 8px;
    background: var(--bg-secondary);
    padding: 12px;
    border-radius: 12px;
    box-shadow: var(--hover-shadow);
    border: 2px solid var(--border-color);
}

.theme-btn {
    padding: 10px 16px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all 0.2s ease;
    background: var(--bg-primary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.theme-btn:hover, .theme-btn.active {
    background: var(--primary-color);
    color: white;
    transform: scale(1.05);
}

/* ==================== HEADER ==================== */
.main-header {
    background: var(--bg-gradient);
    color: white;
    padding: 40px 20px;
    text-align: center;
    box-shadow: var(--card-shadow);
}

.main-header h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.95;
}

.subtitle-hinglish {
    font-size: 1rem;
    opacity: 0.85;
    margin-top: 8px;
    font-style: italic;
}

/* ==================== NAVIGATION ==================== */
.main-nav {
    background: var(--bg-secondary);
    padding: 12px 20px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
    box-shadow: var(--card-shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-btn {
    padding: 10px 18px;
    border: none;
    background: var(--bg-primary);
    color: var(--text-secondary);
    border-radius: 10px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.nav-btn:hover, .nav-btn.active {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.presentation-btn {
    background: linear-gradient(135deg, var(--accent-color), var(--secondary-color));
    color: white;
}

/* ==================== MAIN CONTENT ==================== */
.main-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 30px 20px;
}

.section {
    display: none;
    animation: fadeIn 0.5s ease;
}

.section.active { display: block; }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.section-header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    background: var(--bg-secondary);
    border-radius: 16px;
    box-shadow: var(--card-shadow);
}

.section-header h2 {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    color: var(--primary-dark);
}

.shape-badge {
    display: inline-block;
    padding: 6px 14px;
    background: var(--primary-color);
    color: white;
    border-radius: 20px;
    font-size: 0.85rem;
    margin-left: 10px;
}

.welcome-hinglish {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-top: 10px;
}

/* ==================== CARDS ==================== */
.intro-card, .info-card {
    background: var(--bg-secondary);
    padding: 25px;
    border-radius: 16px;
    box-shadow: var(--card-shadow);
    margin-bottom: 25px;
}

.info-card h3 {
    color: var(--primary-dark);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.info-card p {
    color: var(--text-secondary);
    margin-bottom: 12px;
}

/* ==================== LEVEL BADGES ==================== */
.level-indicator {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin: 15px 0;
}

.level-badge {
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    background: var(--primary-color);
    color: white;
}

.level-badge.kids { background: var(--badge-kids); color: #553C7B; }
.level-badge.student { background: var(--badge-student); color: #1e3a5f; }
.level-badge.advanced { background: var(--badge-advanced); color: #553C7B; }

/* ==================== MULTI-LEVEL CONTENT ==================== */
.multi-level { border-left: 4px solid var(--primary-color); }

.level-content {
    padding: 15px;
    margin: 15px 0;
    border-radius: 12px;
    background: var(--formula-bg);
}

.level-content.kids-level {
    border-left: 4px solid var(--badge-kids);
}

.level-content.student-level {
    border-left: 4px solid var(--badge-student);
}

.level-content.advanced-level {
    border-left: 4px solid var(--badge-advanced);
}

.story-text {
    background: var(--bg-primary);
    padding: 12px;
    border-radius: 8px;
    margin: 10px 0;
    border-left: 3px solid var(--warning-color);
}

.hinglish-text {
    font-style: italic;
    color: var(--text-light);
    padding: 8px 12px;
    background: var(--formula-bg);
    border-radius: 6px;
    margin: 8px 0;
}

.simple-text {
    font-size: 0.95rem;
    color: var(--text-secondary);
    padding: 6px 10px;
    background: var(--bg-primary);
    border-radius: 6px;
    margin: 6px 0;
}

/* ==================== IMPORTANCE GRID ==================== */
.importance-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.importance-item {
    text-align: center;
    padding: 20px;
    background: var(--bg-primary);
    border-radius: 12px;
    transition: transform 0.3s ease;
}

.importance-item:hover { transform: scale(1.05); }
.importance-item .icon { font-size: 3rem; display: block; margin-bottom: 10px; }
.importance-item h4 { color: var(--primary-dark); margin-bottom: 8px; }
.importance-item p { font-size: 0.9rem; color: var(--text-light); }

/* ==================== SHAPE CARDS ==================== */
.shapes-overview {
    background: var(--bg-secondary);
    padding: 25px;
    border-radius: 16px;
    box-shadow: var(--card-shadow);
    margin-bottom: 25px;
}

.shapes-overview h3 {
    text-align: center;
    color: var(--primary-dark);
    margin-bottom: 25px;
}

.shape-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
}

.shape-card {
    background: var(--bg-primary);
    padding: 20px;
    border-radius: 16px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 3px solid transparent;
}

.shape-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--hover-shadow);
}

.shape-card[data-shape="pyramid"]:hover { border-color: #FF8B6B; }
.shape-card[data-shape="rhombus"]:hover { border-color: #6BCBFF; }
.shape-card[data-shape="trapezoid"]:hover { border-color: #8B6BFF; }
.shape-card[data-shape="square"]:hover { border-color: #6BFF8B; }

.shape-preview {
    height: 80px;
    margin: 0 auto 15px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.pyramid-preview {
    width: 0; height: 0;
    border-left: 35px solid transparent;
    border-right: 35px solid transparent;
    border-bottom: 60px solid #FF8B6B;
}

.rhombus-preview {
    width: 50px; height: 50px;
    background: #6BCBFF;
    transform: rotate(45deg);
    border-radius: 4px;
}

.trapezoid-preview {
    width: 0; height: 0;
    border-left: 25px solid transparent;
    border-right: 25px solid transparent;
    border-bottom: 40px solid #8B6BFF;
}

.trapezoid-preview::before {
    content: '';
    position: absolute;
    top: 40px; left: -40px;
    width: 80px; height: 15px;
    background: #8B6BFF;
}

.square-preview {
    width: 50px; height: 50px;
    background: #6BFF8B;
    border-radius: 8px;
}

.shape-card h4 { color: var(--primary-dark); margin-bottom: 8px; }
.shape-card p { font-size: 0.9rem; color: var(--text-light); }

/* Presentation Link Button */
.pres-link-btn, .full-pres-btn {
    margin-top: 10px;
    padding: 10px 20px;
    background: linear-gradient(135deg, var(--accent-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
}

.pres-link-btn:hover, .full-pres-btn:hover {
    transform: scale(1.05);
    box-shadow: var(--hover-shadow);
}

.full-pres-btn {
    display: block;
    width: 100%;
    max-width: 400px;
    margin: 20px auto;
    padding: 15px 30px;
    font-size: 1.1rem;
}

/* ==================== MOTIVATION BOX ==================== */
.motivation-box {
    background: linear-gradient(135deg, var(--success-color), var(--primary-color));
    padding: 25px;
    border-radius: 16px;
    color: white;
    text-align: center;
    margin-bottom: 25px;
}

.motivation-box h3 { margin-bottom: 10px; }
.motivation-box p { opacity: 0.95; }

/* ==================== SHAPE CONTAINER ==================== */
.shape-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    margin-bottom: 25px;
}

@media (max-width: 900px) {
    .shape-container { grid-template-columns: 1fr; }
}

/* ==================== SHAPE VISUALS ==================== */
.shape-visual {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 25px;
    box-shadow: var(--card-shadow);
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 300px;
}

.shape-svg { width: 100%; max-width: 350px; height: auto; }

.pyramid-face.front { fill: #FF8B6B; stroke: var(--primary-dark); stroke-width: 2; }
.pyramid-face.side { fill: #E67A5A; stroke: var(--primary-dark); stroke-width: 2; }
.pyramid-face.side2 { fill: #CC6A4A; stroke: var(--primary-dark); stroke-width: 2; }
.pyramid-base { fill: #8B6B4A; stroke: var(--primary-dark); stroke-width: 2; opacity: 0.8; }
.rhombus-shape { fill: #6BCBFF; stroke: var(--primary-dark); stroke-width: 2; }
.trapezoid-shape { fill: #8B6BFF; stroke: var(--primary-dark); stroke-width: 2; }
.square-shape { fill: #6BFF8B; stroke: var(--primary-dark); stroke-width: 2; }

.diagonal { stroke: var(--accent-color); stroke-width: 2; }
.dimension-line { stroke: var(--warning-color); stroke-width: 2; }
.shape-label { fill: var(--text-primary); font-size: 14px; font-weight: 600; }
.center-point { fill: var(--accent-color); }
.parallel-marker { stroke: var(--text-primary); stroke-width: 2; }
.right-angle-mark { fill: none; stroke: var(--text-primary); stroke-width: 2; }

/* ==================== PROPERTIES LIST ==================== */
.properties-list { list-style: none; padding-left: 0; }
.properties-list li {
    padding: 8px 0;
    padding-left: 25px;
    position: relative;
    color: var(--text-secondary);
}
.properties-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

.memory-trick {
    background: var(--warning-color);
    color: #553C7B;
    padding: 12px;
    border-radius: 8px;
    margin-top: 15px;
    font-weight: 500;
}

/* ==================== WHY EXISTS & MISTAKES ==================== */
.why-exists {
    border-left: 4px solid var(--success-color);
}

.common-mistakes {
    border-left: 4px solid var(--accent-color);
}

.mistake-item {
    display: flex;
    gap: 10px;
    padding: 10px;
    background: var(--bg-primary);
    border-radius: 8px;
    margin: 10px 0;
    align-items: flex-start;
}

.mistake-item span { font-size: 1.2rem; }

/* ==================== MATH SECTION ==================== */
.math-section {
    background: linear-gradient(135deg, var(--bg-secondary), var(--bg-primary));
    padding: 25px;
    border-radius: 16px;
    box-shadow: var(--card-shadow);
    margin-bottom: 25px;
}

.math-section h3 {
    text-align: center;
    color: var(--primary-dark);
    margin-bottom: 20px;
}

.formula-intro {
    text-align: center;
    padding: 15px;
    background: var(--bg-primary);
    border-radius: 10px;
    margin-bottom: 20px;
}

.formula-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.formula-card {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    border-left: 4px solid var(--primary-color);
    transition: transform 0.3s ease;
}

.formula-card:hover { transform: translateY(-5px); }
.formula-card h4 { color: var(--primary-dark); margin-bottom: 12px; }

.formula {
    background: var(--formula-bg);
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 15px;
    text-align: center;
}

.formula-text {
    font-family: 'Courier New', monospace;
    font-size: 1.3rem;
    font-weight: bold;
    color: var(--secondary-color);
}

.formula-breakdown h5 {
    color: var(--primary-dark);
    margin: 15px 0 10px;
}

.formula-breakdown ul {
    list-style: none;
    padding-left: 0;
}

.formula-breakdown li {
    padding: 5px 0;
    padding-left: 20px;
    position: relative;
    color: var(--text-secondary);
}

.formula-breakdown li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

.example-box {
    background: var(--bg-primary);
    padding: 12px;
    border-radius: 8px;
    margin: 12px 0;
    border-left: 3px solid var(--success-color);
}

.alternative-formula {
    background: var(--formula-bg);
    padding: 10px;
    border-radius: 6px;
    margin: 10px 0;
    font-size: 0.95rem;
}

/* ==================== EXAMPLES GRID ==================== */
.examples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 15px;
}

.example-item {
    text-align: center;
    padding: 15px;
    background: var(--bg-primary);
    border-radius: 10px;
    transition: transform 0.3s ease;
}

.example-item:hover { transform: translateY(-3px); }
.example-icon { font-size: 2.5rem; display: block; margin-bottom: 8px; }
.example-item h4 { color: var(--primary-dark); margin-bottom: 5px; font-size: 0.95rem; }
.example-item p { font-size: 0.85rem; color: var(--text-light); }

/* ==================== APPLICATIONS ==================== */
.applications-list { display: flex; flex-direction: column; gap: 10px; }
.app-item {
    padding: 12px;
    background: var(--bg-primary);
    border-radius: 8px;
    color: var(--text-secondary);
}

/* ==================== Q&A SECTION ==================== */
.qa-section { border-left: 4px solid var(--secondary-color); }
.qa-item {
    margin: 15px 0;
    padding: 15px;
    background: var(--bg-primary);
    border-radius: 10px;
}

.qa-question {
    color: var(--primary-dark);
    font-weight: 600;
    margin-bottom: 10px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--border-color);
}

.qa-answer {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ==================== FUN FACTS ==================== */
.fun-facts {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    padding: 25px;
    border-radius: 16px;
    box-shadow: var(--hover-shadow);
    color: white;
    margin-top: 25px;
}

.fun-facts h3 { text-align: center; margin-bottom: 20px; font-size: 1.8rem; }

.facts-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 15px;
}

.fact-item {
    display: flex;
    gap: 12px;
    align-items: flex-start;
}

.fact-number {
    background: white;
    color: var(--secondary-color);
    width: 35px; height: 35px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    flex-shrink: 0;
}

.fact-item p { line-height: 1.6; opacity: 0.95; }

/* ==================== EXPLORE MORE ==================== */
.explore-more-card {
    margin-top: 25px;
    text-align: center;
}

.explore-btn {
    padding: 12px 30px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

.explore-btn:hover {
    transform: scale(1.05);
    box-shadow: var(--hover-shadow);
}

.explore-content {
    margin-top: 20px;
    padding: 20px;
    background: var(--bg-secondary);
    border-radius: 12px;
    box-shadow: var(--card-shadow);
}

.explore-content.hidden { display: none; }
.explore-content h4 { color: var(--primary-dark); margin-bottom: 15px; }

.deep-knowledge {
    margin: 15px 0;
    padding: 15px;
    background: var(--formula-bg);
    border-radius: 8px;
    border-left: 4px solid var(--secondary-color);
}

.deep-knowledge h5 { color: var(--primary-dark); margin-bottom: 10px; }
.deep-knowledge p { color: var(--text-secondary); line-height: 1.7; }

/* ==================== COMPARISON TABLE ==================== */
.comparison-container {
    background: var(--bg-secondary);
    padding: 25px;
    border-radius: 16px;
    box-shadow: var(--card-shadow);
    margin-bottom: 25px;
    overflow-x: auto;
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 800px;
}

.comparison-table th, .comparison-table td {
    padding: 12px;
    text-align: center;
    border: 1px solid var(--border-color);
}

.comparison-table th {
    background: var(--bg-gradient);
    color: white;
    font-weight: 600;
}

.comparison-table td:first-child {
    background: var(--bg-primary);
    font-weight: 500;
    text-align: left;
}

.comparison-table tr:nth-child(even) td { background: var(--formula-bg); }
.comparison-table tr:hover td { background: var(--bg-primary); }

/* ==================== LOGIC CORNER ==================== */
.logic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.logic-card {
    background: var(--bg-secondary);
    padding: 20px;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
}

.logic-card h3 { color: var(--primary-dark); margin-bottom: 15px; }
.logic-card ul { margin: 10px 0; padding-left: 20px; }
.logic-card li { color: var(--text-secondary); margin: 8px 0; }

/* ==================== PRESENTATION MODE ==================== */
.presentation-container { max-width: 900px; margin: 0 auto; }
.presentation-header { text-align: center; margin-bottom: 25px; }
.presentation-header h2 { color: var(--primary-dark); }

.presentation-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
}

.presentation-nav-btn {
    padding: 12px 25px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.presentation-nav-btn:hover:not(:disabled) {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.presentation-nav-btn:disabled {
    background: var(--text-light);
    cursor: not-allowed;
}

.slide-counter {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-secondary);
    min-width: 80px;
    text-align: center;
}

.presentation-slides {
    background: var(--bg-secondary);
    border-radius: 16px;
    box-shadow: var(--hover-shadow);
    overflow: hidden;
    min-height: 500px;
}

.slide { display: none; padding: 40px; animation: slideIn 0.5s ease; }
.slide.active { display: block; }

@keyframes slideIn {
    from { opacity: 0; transform: translateX(50px); }
    to { opacity: 1; transform: translateX(0); }
}

.slide-content { text-align: center; }
.slide-content h3 { font-size: 2rem; color: var(--primary-dark); margin-bottom: 20px; }

.slide-visual {
    height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.slide-emoji { font-size: 5rem; animation: bounce 2s ease-in-out infinite; }

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}

.slide-svg { width: 120px; height: 120px; }
.slide-content h4 { color: var(--secondary-color); margin-bottom: 15px; }

.slide-points {
    list-style: none;
    text-align: left;
    max-width: 600px;
    margin: 0 auto;
}

.slide-points li {
    padding: 10px 0;
    padding-left: 30px;
    position: relative;
    font-size: 1.05rem;
    color: var(--text-secondary);
}

.slide-points li::before { content: '📌'; position: absolute; left: 0; }

.presenter-notes {
    margin-top: 25px;
    padding: 15px;
    background: var(--warning-color);
    color: #553C7B;
    border-radius: 10px;
    font-weight: 500;
}

.thank-you {
    font-size: 1.3rem;
    color: var(--primary-dark);
    margin-top: 20px;
    padding: 15px;
    background: var(--bg-primary);
    border-radius: 10px;
}

.exit-presentation-btn {
    padding: 12px 25px;
    background: var(--accent-color);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
}

/* ==================== CTA SECTION ==================== */
.cta-section {
    text-align: center;
    padding: 25px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 16px;
    color: white;
    font-size: 1.2rem;
    font-weight: 500;
}

/* ==================== FOOTER ==================== */
.main-footer {
    background: var(--text-primary);
    color: white;
    text-align: center;
    padding: 25px;
    margin-top: 40px;
}

.main-footer p { margin: 5px 0; opacity: 0.9; }

/* ==================== RESPONSIVE ==================== */
@media (max-width: 768px) {
    .main-content { padding: 15px; }
    .theme-selector { top: auto; bottom: 20px; right: 10px; }
    .theme-btn { padding: 8px 12px; font-size: 0.8rem; }
    .main-nav { gap: 5px; }
    .nav-btn { padding: 8px 12px; font-size: 0.85rem; }
    .shape-visual { min-height: 250px; padding: 15px; }
    .formula-text { font-size: 1.1rem; }
    .fun-facts { padding: 20px; }
    .fact-item { flex-direction: column; align-items: center; text-align: center; }
    .presentation-slides { min-height: 400px; }
    .slide { padding: 20px; }
    .slide-content h3 { font-size: 1.5rem; }
    .slide-points li { font-size: 0.95rem; }
}

@media (max-width: 480px) {
    .main-header { padding: 20px 10px; }
    .main-header h1 { font-size: 1.5rem; }
    .subtitle { font-size: 0.9rem; }
    .shape-cards { grid-template-columns: 1fr; }
    .examples-grid { grid-template-columns: 1fr; }
    .formula-grid { grid-template-columns: 1fr; }
    .logic-grid { grid-template-columns: 1fr; }
    .presentation-controls { flex-wrap: wrap; }
}

/* ==================== SCROLLBAR ==================== */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg-primary); border-radius: 5px; }
::-webkit-scrollbar-thumb { background: var(--primary-color); border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-dark); }

/* ==================== SELECTION ==================== */
::selection { background: var(--primary-color); color: white; }

/* ==================== LANGUAGE BACK LINK ==================== */
.lang-back {
    position: fixed;
    top: 80px;
    left: 20px;
    z-index: 999;
}

.lang-back a {
    display: inline-block;
    padding: 10px 20px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    text-decoration: none;
    border-radius: 10px;
    box-shadow: var(--card-shadow);
    font-weight: 600;
    transition: all 0.3s ease;
}

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

/* ==================== RTL SUPPORT (URDU) ==================== */
[dir="rtl"] {
    text-align: right;
}

[dir="rtl"] .main-nav {
    direction: rtl;
}

[dir="rtl"] .properties-list li {
    padding-right: 25px;
    padding-left: 0;
}

[dir="rtl"] .properties-list li::before {
    left: auto;
    right: 0;
}

[dir="rtl"] .formula-card {
    border-left: none;
    border-right: 4px solid var(--primary-color);
}

[dir="rtl"] .level-content {
    border-left: none;
    border-right: 4px solid var(--primary-color);
}