/* ============================================
   MATHS01 - Advanced Math Tools Platform
   Modern CSS Framework
   ============================================ */

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #7c3aed;
    --accent: #f59e0b;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --dark: #1e293b;
    --light: #f8fafc;
    --gray: #64748b;
    --gray-light: #e2e8f0;
    --white: #ffffff;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-main: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-math: 'Cambria Math', 'Times New Roman', serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    color: var(--dark);
    min-height: 100vh;
    line-height: 1.6;
}

/* ============================================
   NAVIGATION
   ============================================ */
.navbar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--gray-light);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 0 2rem;
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--primary);
    text-decoration: none;
}

.logo-icon {
    width: 45px;
    height: 45px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: var(--gray);
    font-weight: 600;
    font-size: 0.95rem;
    transition: var(--transition);
    position: relative;
    padding: 0.5rem 0;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transition: var(--transition);
    border-radius: 2px;
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--dark);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 4rem 2rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    animation: float 20s linear infinite;
}

@keyframes float {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50px, 50px); }
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: 2rem;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-top: 2rem;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    display: block;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* ============================================
   SERVICES GRID
   ============================================ */
.services-section {
    padding: 4rem 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 0.5rem;
}

.section-subtitle {
    text-align: center;
    color: var(--gray);
    margin-bottom: 3rem;
    font-size: 1.1rem;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.service-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: block;
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transform: scaleX(0);
    transition: var(--transition);
}

.service-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.service-card:hover::before {
    transform: scaleX(1);
}

.service-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: white;
}

.service-icon.blue { background: linear-gradient(135deg, #3b82f6, #1d4ed8); }
.service-icon.green { background: linear-gradient(135deg, #10b981, #059669); }
.service-icon.purple { background: linear-gradient(135deg, #8b5cf6, #7c3aed); }
.service-icon.orange { background: linear-gradient(135deg, #f59e0b, #d97706); }
.service-icon.red { background: linear-gradient(135deg, #ef4444, #dc2626); }
.service-icon.teal { background: linear-gradient(135deg, #14b8a6, #0d9488); }
.service-icon.indigo { background: linear-gradient(135deg, #6366f1, #4f46e5); }
.service-icon.pink { background: linear-gradient(135deg, #ec4899, #db2777); }

.service-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--dark);
}

.service-card p {
    color: var(--gray);
    font-size: 0.95rem;
    line-height: 1.5;
}

.service-badge {
    display: inline-block;
    background: var(--gray-light);
    color: var(--gray);
    padding: 0.2rem 0.6rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-top: 0.5rem;
}

/* ============================================
   TOOL PAGES
   ============================================ */
.tool-page {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

.tool-header {
    text-align: center;
    margin-bottom: 2rem;
    padding: 2rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius);
    color: white;
}

.tool-header h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.tool-header p {
    opacity: 0.9;
}

.tool-container {
    background: var(--white);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

/* ============================================
   CALCULATOR
   ============================================ */
.calc-display {
    background: var(--dark);
    color: white;
    padding: 1.5rem;
    border-radius: var(--radius-sm);
    margin-bottom: 1rem;
    text-align: right;
    font-size: 2rem;
    font-family: 'Courier New', monospace;
    min-height: 80px;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.calc-history {
    font-size: 0.9rem;
    opacity: 0.7;
    min-height: 20px;
    margin-bottom: 0.5rem;
}

.calc-buttons {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.5rem;
}

.calc-btn {
    padding: 1rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    background: var(--gray-light);
    color: var(--dark);
}

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

.calc-btn.operator {
    background: var(--primary);
    color: white;
}

.calc-btn.operator:hover {
    background: var(--primary-dark);
}

.calc-btn.function {
    background: var(--secondary);
    color: white;
    font-size: 0.9rem;
}

.calc-btn.function:hover {
    background: #6d28d9;
}

.calc-btn.equals {
    background: var(--success);
    color: white;
    grid-column: span 2;
}

.calc-btn.equals:hover {
    background: #059669;
}

.calc-btn.clear {
    background: var(--danger);
    color: white;
}

.calc-btn.clear:hover {
    background: #dc2626;
}

.calc-modes {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.mode-btn {
    padding: 0.5rem 1rem;
    border: 2px solid var(--gray-light);
    background: white;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

.mode-btn.active,
.mode-btn:hover {
    border-color: var(--primary);
    background: var(--primary);
    color: white;
}

/* ============================================
   CONVERTER
   ============================================ */
.converter-grid {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1rem;
    align-items: center;
    margin-bottom: 2rem;
}

.converter-input {
    padding: 1rem;
    border: 2px solid var(--gray-light);
    border-radius: var(--radius-sm);
    font-size: 1.1rem;
    width: 100%;
    transition: var(--transition);
}

.converter-input:focus {
    outline: none;
    border-color: var(--primary);
}

.converter-select {
    padding: 1rem;
    border: 2px solid var(--gray-light);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    width: 100%;
    margin-top: 0.5rem;
    cursor: pointer;
}

.swap-btn {
    background: var(--primary);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.swap-btn:hover {
    transform: rotate(180deg);
    background: var(--primary-dark);
}

.converter-categories {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.cat-btn {
    padding: 0.6rem 1.2rem;
    border: 2px solid var(--gray-light);
    background: white;
    border-radius: 30px;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

.cat-btn.active,
.cat-btn:hover {
    border-color: var(--primary);
    background: var(--primary);
    color: white;
}

.converter-result {
    background: linear-gradient(135deg, #ecfdf5, #d1fae5);
    padding: 1.5rem;
    border-radius: var(--radius-sm);
    text-align: center;
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--success);
    border: 2px solid var(--success);
}

/* ============================================
   GRAPHER
   ============================================ */
.grapher-container {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 2rem;
}

.graph-canvas-container {
    background: var(--dark);
    border-radius: var(--radius-sm);
    padding: 1rem;
    position: relative;
}

#graphCanvas {
    width: 100%;
    height: 500px;
    background: #0f172a;
    border-radius: var(--radius-sm);
}

.graph-controls {
    background: var(--white);
    border-radius: var(--radius-sm);
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.graph-controls h3 {
    margin-bottom: 1rem;
    color: var(--primary);
}

.control-group {
    margin-bottom: 1rem;
}

.control-group label {
    display: block;
    margin-bottom: 0.3rem;
    font-weight: 600;
    font-size: 0.9rem;
}

.control-group input,
.control-group select {
    width: 100%;
    padding: 0.7rem;
    border: 2px solid var(--gray-light);
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
}

.graph-info {
    background: #f0f9ff;
    padding: 1rem;
    border-radius: var(--radius-sm);
    margin-top: 1rem;
    font-size: 0.9rem;
}

.graph-info h4 {
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.graph-info-item {
    padding: 0.3rem 0;
    border-bottom: 1px solid var(--gray-light);
}

.graph-toolbar {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.graph-btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    background: var(--gray-light);
}

.graph-btn:hover {
    background: var(--primary);
    color: white;
}

/* ============================================
   BLACKBOARD
   ============================================ */
.blackboard-container {
    position: relative;
}

#blackboardCanvas {
    width: 100%;
    height: 600px;
    background: #1a1a2e;
    border-radius: var(--radius-sm);
    cursor: crosshair;
    touch-action: none;
}

.board-toolbar {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    align-items: center;
    padding: 1rem;
    background: var(--white);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow);
}

.tool-btn {
    padding: 0.6rem 1rem;
    border: 2px solid var(--gray-light);
    background: white;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.tool-btn.active,
.tool-btn:hover {
    border-color: var(--primary);
    background: var(--primary);
    color: white;
}

.color-picker {
    display: flex;
    gap: 0.3rem;
}

.color-option {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    cursor: pointer;
    border: 3px solid transparent;
    transition: var(--transition);
}

.color-option.active {
    border-color: var(--dark);
    transform: scale(1.2);
}

.size-slider {
    width: 100px;
}

/* ============================================
   FORMULAS
   ============================================ */
.formulas-categories {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.formula-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 1rem;
    border-left: 4px solid var(--primary);
    transition: var(--transition);
}

.formula-card:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow-lg);
}

.formula-title {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.formula-math {
    font-family: var(--font-math);
    font-size: 1.3rem;
    background: #f8fafc;
    padding: 1rem;
    border-radius: var(--radius-sm);
    text-align: center;
    margin: 0.5rem 0;
    border: 1px solid var(--gray-light);
}

.formula-desc {
    color: var(--gray);
    font-size: 0.9rem;
}

.formula-tags {
    display: flex;
    gap: 0.3rem;
    margin-top: 0.5rem;
    flex-wrap: wrap;
}

.formula-tag {
    background: var(--gray-light);
    padding: 0.2rem 0.5rem;
    border-radius: 20px;
    font-size: 0.75rem;
    color: var(--gray);
}

/* ============================================
   WORKSHEET GENERATOR
   ============================================ */
.worksheet-config {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.config-card {
    background: var(--white);
    padding: 1.5rem;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow);
}

.config-card h3 {
    color: var(--primary);
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.worksheet-preview {
    background: white;
    border: 1px solid var(--gray-light);
    border-radius: var(--radius-sm);
    padding: 2rem;
    min-height: 600px;
    font-family: 'Times New Roman', serif;
}

.worksheet-header {
    text-align: center;
    border-bottom: 2px solid var(--dark);
    padding-bottom: 1rem;
    margin-bottom: 2rem;
}

.worksheet-problem {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: #f8fafc;
    border-radius: var(--radius-sm);
}

.problem-number {
    font-weight: 700;
    color: var(--primary);
    margin-right: 0.5rem;
}

/* ============================================
   GEOMETRY TOOL
   ============================================ */
.geometry-container {
    display: grid;
    grid-template-columns: 1fr 280px;
    gap: 2rem;
}

#geometryCanvas {
    width: 100%;
    height: 550px;
    background: white;
    border: 2px solid var(--gray-light);
    border-radius: var(--radius-sm);
}

.geometry-tools {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.geom-tool-btn {
    padding: 0.8rem;
    border: 2px solid var(--gray-light);
    background: white;
    border-radius: var(--radius-sm);
    cursor: pointer;
    text-align: left;
    font-weight: 600;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.geom-tool-btn:hover,
.geom-tool-btn.active {
    border-color: var(--primary);
    background: var(--primary);
    color: white;
}

.geometry-info {
    background: #f0f9ff;
    padding: 1rem;
    border-radius: var(--radius-sm);
    margin-top: 1rem;
    font-size: 0.9rem;
}

/* ============================================
   QUIZ BANK
   ============================================ */
.quiz-container {
    max-width: 800px;
    margin: 0 auto;
}

.quiz-question {
    background: var(--white);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 1.5rem;
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--gray-light);
}

.question-number {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary);
}

.question-timer {
    background: var(--accent);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-weight: 600;
}

.question-text {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.answer-options {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.answer-option {
    padding: 1rem;
    border: 2px solid var(--gray-light);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
    font-size: 1.1rem;
}

.answer-option:hover {
    border-color: var(--primary);
    background: #eff6ff;
}

.answer-option.correct {
    border-color: var(--success);
    background: #ecfdf5;
    color: var(--success);
}

.answer-option.wrong {
    border-color: var(--danger);
    background: #fef2f2;
    color: var(--danger);
}

.quiz-progress {
    background: var(--gray-light);
    height: 8px;
    border-radius: 4px;
    margin-bottom: 2rem;
    overflow: hidden;
}

.quiz-progress-bar {
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    height: 100%;
    border-radius: 4px;
    transition: width 0.5s ease;
}

.quiz-results {
    text-align: center;
    padding: 3rem;
}

.score-circle {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 2rem;
    color: white;
    font-size: 2.5rem;
    font-weight: 800;
}

/* ============================================
   LEGAL PAGES
   ============================================ */
.legal-page {
    max-width: 900px;
    margin: 0 auto;
    padding: 3rem 2rem;
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.legal-page h1 {
    color: var(--primary);
    margin-bottom: 1.5rem;
    font-size: 2rem;
}

.legal-page h2 {
    color: var(--dark);
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.legal-page p {
    margin-bottom: 1rem;
    line-height: 1.8;
    color: var(--gray);
}

/* ============================================
   CONTACT PAGE
   ============================================ */
.contact-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    max-width: 1000px;
    margin: 0 auto;
}

.contact-form {
    background: var(--white);
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--dark);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.8rem;
    border: 2px solid var(--gray-light);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    transition: var(--transition);
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary);
}

.form-group textarea {
    resize: vertical;
    min-height: 150px;
}

.submit-btn {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--radius-sm);
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    width: 100%;
}

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

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.info-card {
    background: var(--white);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.info-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.3rem;
    flex-shrink: 0;
}

.info-content h3 {
    font-size: 1.1rem;
    margin-bottom: 0.3rem;
}

.info-content p {
    color: var(--gray);
    font-size: 0.95rem;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
    background: var(--dark);
    color: white;
    padding: 3rem 2rem 1rem;
    margin-top: 4rem;
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: var(--accent);
}

.footer-section a {
    color: #94a3b8;
    text-decoration: none;
    display: block;
    padding: 0.3rem 0;
    transition: var(--transition);
}

.footer-section a:hover {
    color: white;
    padding-left: 5px;
}

.footer-bottom {
    border-top: 1px solid #334155;
    padding-top: 1.5rem;
    text-align: center;
    color: #94a3b8;
    font-size: 0.9rem;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 1rem;
        box-shadow: var(--shadow);
    }

    .nav-links.active {
        display: flex;
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero-stats {
        flex-direction: column;
        gap: 1rem;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .calc-buttons {
        grid-template-columns: repeat(4, 1fr);
    }

    .converter-grid {
        grid-template-columns: 1fr;
    }

    .grapher-container,
    .geometry-container {
        grid-template-columns: 1fr;
    }

    .contact-container {
        grid-template-columns: 1fr;
    }

    .tool-page {
        padding: 1rem;
    }
}

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

.animate-in {
    animation: fadeIn 0.6s ease forwards;
}

/* Print styles */
@media print {
    .navbar, .footer, .board-toolbar, .graph-controls {
        display: none !important;
    }

    .tool-container {
        box-shadow: none;
        border: 1px solid #000;
    }

    #blackboardCanvas,
    #graphCanvas {
        border: 1px solid #000;
    }
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--light);
}

::-webkit-scrollbar-thumb {
    background: var(--gray);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary);
}