/* ===================================
   Reset & Base Styles
   =================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #10b981;
    --accent-color: #f59e0b;
    --danger-color: #ef4444;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

body {
    font-family: 'Noto Sans KR', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

section {
    padding: 80px 0;
}

/* ===================================
   Navigation
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.nav-brand h2 {
    color: var(--primary-color);
    font-size: 24px;
    font-weight: 700;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
    align-items: center;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 15px;
    transition: color 0.3s ease;
    position: relative;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

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

.nav-menu a:hover::after {
    width: 100%;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--primary-color);
    cursor: pointer;
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    background: var(--gradient-primary);
    padding: 180px 0 120px;
    text-align: center;
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="40" height="40" patternUnits="userSpaceOnUse"><path d="M 40 0 L 0 0 0 40" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 64px;
    font-weight: 900;
    margin-bottom: 10px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
    font-size: 32px;
    font-weight: 300;
    margin-bottom: 30px;
    opacity: 0.95;
}

.hero-description {
    font-size: 20px;
    margin-bottom: 40px;
    opacity: 0.9;
}

.cta-button {
    display: inline-block;
    padding: 16px 40px;
    background: white;
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 50px;
    font-weight: 600;
    font-size: 18px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.cta-button i {
    margin-left: 10px;
}

/* ===================================
   Section Titles
   =================================== */
.section-title {
    font-size: 42px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.section-subtitle {
    font-size: 18px;
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 50px;
}

/* ===================================
   Agenda Section
   =================================== */
.agenda-section {
    background: var(--bg-secondary);
}

.agenda-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.agenda-item {
    background: white;
    padding: 40px 30px;
    border-radius: 16px;
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.agenda-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.agenda-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background: var(--gradient-primary);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 36px;
    color: white;
}

.agenda-item h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.agenda-item p {
    color: var(--text-secondary);
    font-size: 15px;
}

/* ===================================
   Intro Section
   =================================== */
.intro-section {
    background: white;
}

.intro-content {
    max-width: 1000px;
    margin: 0 auto;
}

.intro-description {
    font-size: 20px;
    line-height: 1.8;
    text-align: center;
    margin-bottom: 60px;
    color: var(--text-primary);
}

.intro-description strong {
    color: var(--primary-color);
    font-weight: 700;
}

.intro-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--bg-secondary);
    padding: 40px 30px;
    border-radius: 16px;
    text-align: center;
    transition: all 0.3s ease;
}

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

.feature-card i {
    font-size: 48px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 15px;
}

/* ===================================
   Activities Section (4 Steps)
   =================================== */
.activities-section {
    background: var(--bg-secondary);
}

.steps-container {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 20px;
    margin-top: 60px;
}

.step-card {
    background: white;
    padding: 40px 30px;
    border-radius: 16px;
    text-align: center;
    flex: 0 0 200px;
    position: relative;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

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

.step-number {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 700;
    box-shadow: var(--shadow-md);
}

.step-icon {
    font-size: 48px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.step-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.step-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.step-arrow {
    font-size: 28px;
    color: var(--primary-color);
    flex: 0 0 30px;
}

/* ===================================
   Game Modes Section
   =================================== */
.game-modes-section {
    background: white;
}

.game-modes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 40px;
    margin-top: 50px;
    margin-bottom: 80px;
}

.game-mode-card {
    background: var(--bg-secondary);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

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

.mode-header {
    padding: 30px;
    color: white;
    display: flex;
    align-items: center;
    gap: 15px;
}

.live-mode .mode-header {
    background: var(--gradient-primary);
}

.homework-mode .mode-header {
    background: var(--gradient-secondary);
}

.mode-header i {
    font-size: 36px;
}

.mode-header h3 {
    font-size: 24px;
    font-weight: 700;
}

.mode-content {
    padding: 30px;
    background: white;
}

.mode-content p {
    font-size: 16px;
    line-height: 1.8;
    color: var(--text-primary);
    margin-bottom: 20px;
}

.mode-features {
    list-style: none;
}

.mode-features li {
    padding: 12px 0;
    color: var(--text-secondary);
    font-size: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.mode-features i {
    color: var(--secondary-color);
    font-size: 18px;
}

.individual-mode-section {
    margin-top: 60px;
    padding: 50px;
    background: var(--bg-secondary);
    border-radius: 20px;
}

.subsection-title {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.badge-new {
    display: inline-block;
    padding: 6px 16px;
    background: var(--accent-color);
    color: white;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 700;
    margin-right: 10px;
}

.subsection-description {
    text-align: center;
    color: var(--text-secondary);
    font-size: 18px;
    margin-bottom: 40px;
}

.individual-modes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.individual-mode-card {
    background: white;
    padding: 40px 30px;
    border-radius: 16px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
}

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

.mode-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto 20px;
    background: var(--gradient-success);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: white;
}

.individual-mode-card h4 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.individual-mode-card p {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.6;
}

/* ===================================
   Platform Section
   =================================== */
.platform-section {
    background: var(--bg-secondary);
}

.platform-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 40px;
    margin-top: 50px;
}

.platform-card {
    background: white;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

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

.card-header {
    padding: 30px;
    background: var(--gradient-primary);
    color: white;
    display: flex;
    align-items: center;
    gap: 15px;
}

.card-header i {
    font-size: 36px;
}

.card-header h3 {
    font-size: 24px;
    font-weight: 700;
}

.card-body {
    padding: 30px;
}

.card-body p {
    color: var(--text-primary);
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 25px;
}

.tool-list {
    list-style: none;
}

.tool-list li {
    padding: 12px 0;
    color: var(--text-secondary);
    font-size: 15px;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 1px solid var(--border-color);
}

.tool-list li:last-child {
    border-bottom: none;
}

.tool-list i {
    color: var(--primary-color);
    font-size: 16px;
}

/* ===================================
   AI Section
   =================================== */
.ai-section {
    background: white;
}

.ai-features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.ai-feature-card {
    background: var(--bg-secondary);
    padding: 40px 30px;
    border-radius: 20px;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

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

.ai-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 25px;
    background: var(--gradient-primary);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 40px;
    color: white;
}

.ai-feature-card h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 15px;
    text-align: center;
    color: var(--text-primary);
}

.ai-feature-card > p {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.8;
    text-align: center;
    margin-bottom: 20px;
}

.ai-feature-list {
    list-style: none;
    margin-top: 20px;
}

.ai-feature-list li {
    padding: 10px 0;
    color: var(--text-secondary);
    font-size: 14px;
    position: relative;
    padding-left: 20px;
}

.ai-feature-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: 700;
}

/* ===================================
   Support Section
   =================================== */
.support-section {
    background: var(--bg-secondary);
}

.support-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.support-card {
    background: white;
    padding: 40px 30px;
    border-radius: 16px;
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

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

.support-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto 20px;
    background: var(--gradient-secondary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: white;
}

.support-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.support-card p {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.6;
}

/* ===================================
   Report Section
   =================================== */
.report-section {
    background: white;
}

.report-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 40px;
    margin-top: 50px;
}

.report-feature {
    background: var(--bg-secondary);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

.report-feature:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.report-feature-header {
    padding: 30px;
    background: var(--gradient-primary);
    color: white;
    display: flex;
    align-items: center;
    gap: 15px;
}

.report-feature-header i {
    font-size: 36px;
}

.report-feature-header h3 {
    font-size: 24px;
    font-weight: 700;
}

.report-feature-body {
    padding: 30px;
    background: white;
}

.report-feature-body p {
    color: var(--text-primary);
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 25px;
}

.report-feature-body ul {
    list-style: none;
}

.report-feature-body ul li {
    padding: 12px 0;
    color: var(--text-secondary);
    font-size: 15px;
    position: relative;
    padding-left: 25px;
}

.report-feature-body ul li::before {
    content: '●';
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

/* ===================================
   Benefits Section
   =================================== */
.benefits-section {
    background: var(--bg-secondary);
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.benefit-card {
    background: white;
    padding: 40px 35px;
    border-radius: 20px;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.benefit-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: var(--gradient-primary);
}

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

.benefit-number {
    font-size: 48px;
    font-weight: 900;
    color: var(--primary-light);
    opacity: 0.3;
    margin-bottom: 15px;
}

.benefit-card h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.benefit-card p {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.8;
}

/* ===================================
   CTA Section
   =================================== */
.cta-section {
    background: var(--gradient-primary);
    color: white;
    text-align: center;
    padding: 100px 0;
}

.cta-content h2 {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 20px;
}

.cta-content p {
    font-size: 20px;
    margin-bottom: 40px;
    opacity: 0.95;
}

.cta-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn-primary, .btn-secondary {
    padding: 16px 40px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    font-size: 18px;
    transition: all 0.3s ease;
    display: inline-block;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

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

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

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    font-size: 24px;
    margin-bottom: 15px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 20px;
}

.footer-section p {
    opacity: 0.8;
    font-size: 14px;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 12px;
}

.footer-section ul li a {
    color: white;
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.footer-section ul li a:hover {
    opacity: 1;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    opacity: 0.6;
    font-size: 14px;
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 1024px) {
    .steps-container {
        flex-direction: column;
    }

    .step-arrow {
        transform: rotate(90deg);
        margin: 10px 0;
    }

    .game-modes-grid {
        grid-template-columns: 1fr;
    }

    .report-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: block;
    }

    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow-lg);
    }

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

    .hero {
        padding: 140px 0 80px;
    }

    .hero-title {
        font-size: 42px;
    }

    .hero-subtitle {
        font-size: 24px;
    }

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

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

    .platform-content {
        grid-template-columns: 1fr;
    }

    .ai-features-grid {
        grid-template-columns: 1fr;
    }

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

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

    .cta-content h2 {
        font-size: 32px;
    }

    section {
        padding: 60px 0;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 32px;
    }

    .hero-subtitle {
        font-size: 20px;
    }

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

    .cta-button {
        padding: 14px 30px;
        font-size: 16px;
    }

    .individual-modes-grid {
        grid-template-columns: 1fr;
    }
}

/* ===================================
   Animations
   =================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

/* Smooth Scroll */
html {
    scroll-behavior: smooth;
}

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