/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-500: #1e40af;
    --primary-600: #1e3a8a;
    --primary-700: #172554;
    --slate-50: #f8fafc;
    --slate-100: #f1f5f9;
    --slate-200: #e2e8f0;
    --slate-300: #cbd5e1;
    --slate-500: #64748b;
    --slate-600: #475569;
    --slate-700: #334155;
    --slate-800: #1e293b;
    --slate-900: #0f172a;
    --white: #ffffff;
    --success: #059669;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--slate-800);
    background: var(--white);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Typography */
h1, h2, h3 {
    font-weight: 700;
    line-height: 1.2;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    text-decoration: none;
    border-radius: 8px;
    transition: all 0.2s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--primary-500);
    color: #ffffff;
    padding: 12px 24px;
    font-size: 16px;
}

.btn-primary:hover {
    background: var(--primary-600);
    transform: translateY(-1px);
}

.btn-large {
    padding: 16px 32px;
    font-size: 18px;
}

.btn-full {
    width: 100%;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--white);
    border-bottom: 1px solid var(--slate-200);
    z-index: 100;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo-text {
    font-size: 28px;
    font-weight: 800;
    color: var(--slate-800);
}

.logo-highlight {
    color: var(--primary-500);
}

.nav {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav a {
    text-decoration: none;
    color: var(--slate-600);
    font-weight: 500;
    font-size: 16px;
    transition: color 0.2s;
}

.nav a:hover {
    color: var(--primary-500);
}

.nav .btn {
    margin-left: 8px;
}

.nav .btn-primary {
    color: #ffffff;
}

/* Hero Section */
.hero {
    padding: 120px 0 0;
    background: var(--white);
}

.hero .container {
    max-width: 900px;
}

.hero-centered {
    text-align: center;
}

.hero-centered .hero-subtitle {
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-centered .hero-actions {
    justify-content: center;
}

.hero-badge {
    display: inline-block;
    background: var(--slate-100);
    color: var(--slate-600);
    padding: 10px 20px;
    border-radius: 100px;
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 24px;
    text-decoration: none;
    border: 1px solid var(--slate-200);
    transition: all 0.2s ease;
}

.hero-badge:hover {
    background: var(--slate-200);
    border-color: var(--slate-300);
}

.hero-badge strong {
    color: var(--primary-500);
    font-weight: 700;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    color: var(--slate-900);
    margin-bottom: 24px;
    letter-spacing: -0.02em;
}

.hero-title .highlight {
    color: var(--primary-500);
}

.hero-subtitle {
    font-size: 20px;
    color: var(--slate-600);
    margin-bottom: 16px;
    max-width: 540px;
    line-height: 1.7;
}

.text-highlight {
    background: linear-gradient(120deg, #dbeafe 0%, #bfdbfe 100%);
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 600;
    color: var(--primary-600);
}

/* SymPy Banner - Full Width */
.sympy-banner {
    background: linear-gradient(135deg, var(--slate-900) 0%, var(--primary-700) 100%);
    padding: 24px 24px;
    margin-top: 32px;
    text-align: center;
}

.sympy-text {
    font-size: 20px;
    color: rgba(255, 255, 255, 0.9);
    text-align: center;
    font-weight: 400;
    margin: 0;
}

.sympy-badge {
    display: inline-block;
    background: #22c55e;
    color: #000000;
    font-size: 20px;
    font-weight: 700;
    text-decoration: none;
    padding: 4px 14px;
    border-radius: 100px;
    transition: all 0.2s ease;
    margin: 0 4px;
}

.sympy-badge:hover {
    background: #16a34a;
    transform: scale(1.05);
}

/* Hero Actions after banner */
.hero .hero-actions.hero-centered {
    justify-content: center;
    margin-top: 32px;
    padding-bottom: 20px;
}

.hero-topics {
    font-size: 15px;
    color: var(--slate-600);
    margin-bottom: 12px;
    font-style: italic;
}

.topics-highlight {
    font-style: normal;
    font-weight: 700;
    color: var(--primary-500);
    background: #dbeafe;
    padding: 2px 10px;
    border-radius: 4px;
}

.hero-boards {
    font-size: 15px;
    font-weight: 600;
    color: var(--slate-500);
    letter-spacing: 0.05em;
    margin-bottom: 32px;
}

/* Question Builder Hero Section */
.question-builder-hero {
    padding: 80px 0 100px;
    background: var(--slate-50);
}

.qb-header {
    text-align: center;
    margin-bottom: 50px;
}

.qb-header .section-title {
    font-size: 44px;
    margin-bottom: 20px;
}

.qb-header .section-subtitle {
    font-size: 20px;
    max-width: 700px;
    margin: 0 auto;
}

.qb-hero-layout {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 50px;
    align-items: center;
}

.qb-content .section-title {
    font-size: 36px;
    margin-bottom: 16px;
}

.qb-content .section-subtitle {
    font-size: 18px;
    margin-bottom: 24px;
}

/* Section Styles */
.section-title {
    font-size: 44px;
    font-weight: 800;
    color: var(--slate-900);
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.section-subtitle {
    font-size: 20px;
    color: var(--slate-600);
    max-width: 640px;
    line-height: 1.7;
}

/* Features Section */
.features {
    padding: 100px 0;
    background: var(--white);
}

.features .section-title {
    text-align: center;
    margin-bottom: 60px;
}

.features-list {
    max-width: 1000px;
    margin: 0 auto;
}

.feature-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    padding: 48px 0;
    border-bottom: 1px solid var(--slate-200);
}

.feature-row:last-child {
    border-bottom: none;
}

.feature-item h3 {
    font-size: 26px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.feature-item p {
    font-size: 18px;
    color: var(--slate-600);
    line-height: 1.8;
}

.feature-highlight {
    background: var(--primary-500);
    padding: 32px;
    border-radius: 12px;
    position: relative;
}

.feature-highlight h3 {
    color: #ffffff;
}

.feature-highlight p {
    color: rgba(255, 255, 255, 0.9);
}

.feature-highlight strong {
    color: #ffffff;
}

/* Blueprint Section */
.blueprint-section {
    padding: 100px 0;
    background: var(--slate-50);
}

.blueprint-section .container {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 60px;
    align-items: center;
}

.blueprint-image img {
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
}

.blueprint-features {
    list-style: none;
    margin-top: 32px;
}

.blueprint-features li {
    font-size: 18px;
    color: var(--slate-700);
    padding: 12px 0;
    padding-left: 32px;
    position: relative;
}

.blueprint-features li::before {
    content: "—";
    position: absolute;
    left: 0;
    color: var(--primary-500);
    font-weight: 700;
}

/* How It Works */
.how-it-works {
    padding: 100px 0;
    background: var(--white);
}

.how-it-works .section-title {
    text-align: center;
    margin-bottom: 60px;
}

.steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 32px;
    margin-bottom: 60px;
}

.step {
    text-align: center;
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--primary-500);
    color: var(--white);
    font-size: 28px;
    font-weight: 700;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
}

.step h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--slate-800);
    margin-bottom: 12px;
}

.step p {
    font-size: 16px;
    color: var(--slate-600);
    line-height: 1.6;
}

.screenshot-showcase img {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
    display: block;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
}

/* Question Builder Section */
.question-builder {
    padding: 100px 0;
    background: var(--slate-50);
}

.question-builder .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.qb-features {
    list-style: none;
    margin-top: 32px;
}

.qb-features li {
    font-size: 18px;
    color: var(--slate-700);
    padding: 12px 0;
    padding-left: 32px;
    position: relative;
}

.qb-features li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success);
    font-weight: 700;
}

.qb-image img,
.qb-video video {
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
}

/* Print Preview Section */
.print-preview-section {
    padding: 100px 0;
    background: var(--slate-50);
}

.print-preview-section .container {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 60px;
    align-items: center;
}

.print-features {
    list-style: none;
    margin-top: 32px;
}

.print-features li {
    font-size: 18px;
    color: var(--slate-700);
    padding: 12px 0;
    padding-left: 32px;
    position: relative;
}

.print-features li::before {
    content: "—";
    position: absolute;
    left: 0;
    color: var(--primary-500);
    font-weight: 700;
}

.print-image img {
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.12);
}

/* Coverage Section */
.coverage-section {
    padding: 100px 0;
    background: var(--white);
}

.coverage-section .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.coverage-image img {
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
}

.coverage-stats {
    display: flex;
    gap: 40px;
    margin-top: 40px;
}

.stat {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 32px;
    font-weight: 800;
    color: var(--primary-500);
}

.stat-label {
    font-size: 14px;
    color: var(--slate-600);
    font-weight: 500;
}

/* Demo Section */
.demo-section {
    padding: 100px 0;
    background: var(--slate-50);
}

.demo-content {
    max-width: 560px;
    margin: 0 auto;
    text-align: center;
}

.demo-content .section-title {
    margin-bottom: 16px;
}

.demo-content .section-subtitle {
    margin: 0 auto 40px;
}

.demo-form {
    background: var(--white);
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
    text-align: left;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--slate-700);
    margin-bottom: 8px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 16px;
    font-size: 16px;
    font-family: inherit;
    border: 1px solid var(--slate-300);
    border-radius: 8px;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.demo-note {
    margin-top: 20px;
    font-size: 14px;
    color: var(--slate-500);
}

/* Footer */
.footer {
    background: var(--slate-900);
    color: var(--white);
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 2fr;
    gap: 60px;
    padding-bottom: 40px;
    border-bottom: 1px solid var(--slate-700);
}

.footer-brand .logo-text {
    color: var(--white);
    margin-bottom: 16px;
    display: block;
}

.footer-brand p {
    color: var(--slate-400);
    font-size: 15px;
    line-height: 1.7;
    max-width: 320px;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
}

.footer-column h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--slate-300);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 20px;
}

.footer-column a {
    display: block;
    color: var(--slate-400);
    text-decoration: none;
    font-size: 15px;
    margin-bottom: 12px;
    transition: color 0.2s;
}

.footer-column a:hover {
    color: var(--white);
}

.footer-bottom {
    padding-top: 30px;
    text-align: center;
}

.footer-bottom p {
    color: var(--slate-500);
    font-size: 14px;
}

/* Responsive */
@media (max-width: 1024px) {
    .hero .container,
    .question-builder .container,
    .coverage-section .container,
    .print-preview-section .container,
    .blueprint-section .container {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .qb-hero-layout {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .qb-header .section-title {
        font-size: 36px;
    }

    .qb-content {
        text-align: center;
    }

    .qb-content .section-subtitle {
        margin-left: auto;
        margin-right: auto;
    }

    .qb-features {
        text-align: left;
        max-width: 400px;
        margin-left: auto;
        margin-right: auto;
    }

    .sympy-text {
        font-size: 18px;
    }

    .hero-title {
        font-size: 44px;
    }

    .section-title {
        font-size: 36px;
    }

    .feature-row {
        gap: 40px;
    }

    .steps {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}

@media (max-width: 768px) {
    .nav {
        gap: 16px;
    }

    .nav a:not(.btn) {
        display: none;
    }

    .hero {
        padding: 100px 0 40px;
    }

    .hero-title {
        font-size: 32px;
    }

    .hero-subtitle {
        font-size: 17px;
    }

    .hero-topics {
        font-size: 14px;
    }

    .question-builder-hero {
        padding: 40px 0 60px;
    }

    .question-builder-hero .hero-sympy {
        font-size: 16px;
        margin-bottom: 30px;
        padding-left: 16px;
    }

    .qb-content .section-title {
        font-size: 28px;
    }

    .qb-content .section-subtitle {
        font-size: 16px;
    }

    .section-title {
        font-size: 30px;
    }

    .section-subtitle {
        font-size: 18px;
    }

    .feature-row {
        grid-template-columns: 1fr;
        gap: 32px;
        padding: 32px 0;
    }

    .feature-item h3 {
        font-size: 22px;
    }

    .feature-item p {
        font-size: 16px;
    }

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

    .coverage-stats {
        flex-direction: column;
        gap: 20px;
    }

    .footer-links {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .demo-form {
        padding: 24px;
    }
}