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

:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --text-color: #333;
    --bg-color: #ffffff;
    --border-color: #dee2e6;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

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

/* Header Styles */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1.5rem 0;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.logo h1 {
    font-size: 2rem;
    margin-bottom: 0.25rem;
}

.logo .subtitle {
    font-size: 1rem;
    opacity: 0.9;
}

.nav {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
}

.nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: opacity 0.3s;
}

.nav a:hover {
    opacity: 0.8;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 5rem 0;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.hero-description {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

.hero-badges {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 2rem;
}

.badge {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

/* Button Styles */
.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    cursor: pointer;
    border: 2px solid transparent;
}

.btn-primary {
    background: white;
    color: #667eea;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

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

.btn-secondary:hover {
    background: white;
    color: #667eea;
}

.btn-large {
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

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

/* Section Styles */
section {
    padding: 4rem 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--dark-color);
}

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

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
    text-align: center;
}

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

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--dark-color);
}

.feature-card p {
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.feature-card p.chinese {
    color: var(--secondary-color);
    font-size: 0.9rem;
}

/* Categories Section */
.categories {
    background: white;
}

.categories-table {
    max-width: 800px;
    margin: 0 auto;
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    box-shadow: var(--shadow);
    border-radius: 8px;
    overflow: hidden;
}

thead {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

th, td {
    padding: 1rem;
    text-align: center;
}

tbody tr:nth-child(even) {
    background: var(--light-color);
}

tbody tr:hover {
    background: #e9ecef;
}

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

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.tech-item {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
    text-align: center;
}

.tech-item h4 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.tech-item p {
    color: var(--text-color);
    font-weight: 500;
}

/* Download Section */
.download {
    background: white;
}

.download-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.download-info {
    background: var(--light-color);
    padding: 2rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    text-align: left;
}

.download-info h3 {
    margin-bottom: 1rem;
    color: var(--dark-color);
}

.download-info ul {
    list-style: none;
}

.download-info li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.download-info li:last-child {
    border-bottom: none;
}

.download-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

/* Documentation Section */
.documentation {
    background: var(--light-color);
}

.docs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.doc-card {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transition: transform 0.3s;
}

.doc-card:hover {
    transform: translateY(-5px);
}

.doc-card h3 {
    color: var(--dark-color);
    margin-bottom: 1rem;
}

.doc-card p {
    color: var(--text-color);
    margin-bottom: 1rem;
}

.doc-card a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s;
}

.doc-card a:hover {
    color: #0056b3;
}

/* Contributing Section */
.contributing {
    background: white;
}

.contributing-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.contributing-content > p {
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.contributing-content p.chinese {
    color: var(--secondary-color);
    margin-bottom: 2rem;
}

.contribution-ideas {
    background: var(--light-color);
    padding: 2rem;
    border-radius: 8px;
    margin: 2rem 0;
    text-align: left;
}

.contribution-ideas h3 {
    margin-bottom: 1rem;
    color: var(--dark-color);
}

.contribution-ideas ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 0.75rem;
}

.contribution-ideas li {
    padding: 0.5rem;
}

/* Footer */
.footer {
    background: var(--dark-color);
    color: white;
    padding: 3rem 0 1rem;
}

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

.footer-info h3,
.footer-links h4,
.footer-license h4 {
    margin-bottom: 1rem;
}

.footer-info p.chinese {
    opacity: 0.8;
    font-size: 0.9rem;
}

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

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s;
}

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

.footer-license p {
    margin-bottom: 0.5rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    margin-bottom: 0.5rem;
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-description {
        font-size: 1.2rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .nav {
        gap: 1rem;
    }

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

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

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .download-info {
        text-align: center;
    }

    .contribution-ideas {
        text-align: center;
    }

    .contribution-ideas ul {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .header-content {
        flex-direction: column;
        text-align: center;
    }

    .hero {
        padding: 3rem 0;
    }

    .hero-title {
        font-size: 1.5rem;
    }

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

    .btn {
        padding: 0.6rem 1.5rem;
    }

    section {
        padding: 2rem 0;
    }
}

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

/* Selection Color */
::selection {
    background: #667eea;
    color: white;
}

/* Focus Styles for Accessibility */
a:focus,
button:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}