:root {
    --primary-color: #E1306C;
    --primary-dark: #C13584;
    --secondary-color: #F77737;
    --accent-color: #833AB4;
    --background-color: #FAFAFA;
    --surface-color: #FFFFFF;
    --text-primary: #262626;
    --text-secondary: #8E8E8E;
    --border-color: #DBDBDB;
    --gradient-start: #833AB4;
    --gradient-mid: #E1306C;
    --gradient-end: #F77737;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
}

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

/* Navigation */
.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 40px;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: white;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--gradient-start) 0%, var(--gradient-mid) 50%, var(--gradient-end) 100%);
    min-height: 80vh;
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 80%;
    height: 150%;
    background: radial-gradient(ellipse, rgba(255,255,255,0.15) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 120px 24px 60px;
    color: white;
}

.hero h1 {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 24px;
    opacity: 0.95;
}

.hero-description {
    font-size: 1.125rem;
    max-width: 600px;
    margin-bottom: 40px;
    opacity: 0.9;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
    cursor: pointer;
    border: none;
}

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

.btn-primary:hover {
    background: rgba(255, 255, 255, 0.9);
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

/* Preview Section */
.preview {
    margin-top: -80px;
    padding: 0 24px 80px;
    position: relative;
    z-index: 10;
}

.preview-image {
    width: 100%;
    max-width: 900px;
    display: block;
    margin: 0 auto;
    border-radius: 16px;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.2);
}

/* Section Styles */
section {
    padding: 100px 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 60px;
    color: var(--text-primary);
}

.subsection-title {
    font-size: 1.5rem;
    font-weight: 600;
    text-align: center;
    margin: 60px 0 32px;
    color: var(--text-primary);
}

/* Features */
.features {
    background: var(--surface-color);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
}

.feature-card {
    background: var(--background-color);
    padding: 36px;
    border-radius: 20px;
    transition: all 0.3s;
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
    border-color: var(--primary-color);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Demo Section */
.demo {
    background: var(--background-color);
}

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

.demo-video {
    max-width: 360px;
    width: 100%;
    border-radius: 24px;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.15);
}

.demo-caption {
    margin-top: 20px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Architecture Section */
.architecture {
    background: var(--surface-color);
}

.arch-flow {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
    margin-bottom: 60px;
}

.arch-item {
    background: var(--background-color);
    padding: 24px 32px;
    border-radius: 16px;
    text-align: center;
    border: 2px solid var(--border-color);
    transition: all 0.3s;
}

.arch-item.highlight {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, rgba(225, 48, 108, 0.05), rgba(131, 58, 180, 0.05));
}

.arch-icon {
    font-size: 2rem;
    margin-bottom: 8px;
}

.arch-name {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.arch-desc {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

.arch-arrow {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: bold;
}

.fragments-grid {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 16px;
}

.fragment-card {
    display: flex;
    align-items: center;
    gap: 12px;
    background: var(--background-color);
    padding: 16px 24px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.fragment-icon {
    font-size: 1.5rem;
}

.fragment-name {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.fragment-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Tech Stack */
.tech-stack {
    background: var(--background-color);
}

.tech-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
    max-width: 900px;
    margin: 0 auto;
}

.tech-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 24px 32px;
    background: var(--surface-color);
    border-radius: 16px;
    min-width: 160px;
    border: 1px solid var(--border-color);
    transition: all 0.2s;
}

.tech-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    border-color: var(--primary-color);
}

.tech-item.firebase {
    background: linear-gradient(135deg, #FFCA28, #FFA000);
    border: none;
}

.tech-item.firebase .tech-label,
.tech-item.firebase .tech-value {
    color: white;
}

.tech-label {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 8px;
}

.tech-value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Firebase Grid */
.firebase-grid {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 24px;
    max-width: 900px;
    margin: 0 auto;
}

.firebase-item {
    background: var(--surface-color);
    padding: 32px;
    border-radius: 16px;
    text-align: center;
    min-width: 200px;
    border: 1px solid var(--border-color);
    transition: all 0.3s;
}

.firebase-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.08);
}

.firebase-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.firebase-name {
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.firebase-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Getting Started */
.getting-started {
    background: var(--surface-color);
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.step-card {
    background: var(--background-color);
    padding: 32px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    position: relative;
}

.step-number {
    position: absolute;
    top: -16px;
    left: 24px;
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
}

.step-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.step-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.step-card code {
    display: inline-block;
    background: var(--surface-color);
    padding: 8px 12px;
    border-radius: 8px;
    font-family: 'SF Mono', 'Consolas', monospace;
    font-size: 0.85rem;
    color: var(--primary-dark);
    border: 1px solid var(--border-color);
    word-break: break-all;
}

/* CTA Section */
.cta {
    background: linear-gradient(135deg, var(--gradient-start) 0%, var(--gradient-mid) 50%, var(--gradient-end) 100%);
    text-align: center;
    color: white;
}

.cta h2 {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.cta p {
    font-size: 1.125rem;
    margin-bottom: 32px;
    opacity: 0.9;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: rgba(255, 255, 255, 0.7);
    padding: 40px 0;
    text-align: center;
}

.footer p {
    margin-bottom: 12px;
}

.footer a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
}

.footer a:hover {
    color: white;
}

/* Responsive */
@media (max-width: 768px) {
    .nav {
        padding: 16px 24px;
    }

    .nav-links {
        display: none;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.25rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 2rem;
        margin-bottom: 40px;
    }

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

    .arch-flow {
        flex-direction: column;
    }

    .arch-arrow {
        transform: rotate(90deg);
    }

    .fragments-grid {
        flex-direction: column;
        align-items: center;
    }

    .fragment-card {
        width: 100%;
        max-width: 280px;
    }

    .tech-item {
        min-width: 140px;
        padding: 20px 24px;
    }

    .firebase-grid {
        flex-direction: column;
        align-items: center;
    }

    .firebase-item {
        width: 100%;
        max-width: 300px;
    }

    .cta h2 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 2rem;
    }

    .hero-description br {
        display: none;
    }

    .preview {
        margin-top: -40px;
    }

    .step-card code {
        font-size: 0.75rem;
    }
}