:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --secondary: #f472b6;
    --background: #0f0f23;
    --surface: #1a1b2e;
    --text: #e2e8f0;
    --text-muted: #94a3b8;
    --border: #2d3748;
}

[data-theme="light"] {
    --background: #ffffff;
    --surface: #f8fafc;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
}

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

body {
    font-family: 'Inter', sans-serif;
    background: var(--background);
    color: var(--text);
    line-height: 1.6;
    transition: all 0.3s ease;
}

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

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(15, 15, 35, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 600;
}

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

.nav-link {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

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

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 0.5rem;
    transition: background 0.3s ease;
}

.theme-toggle:hover {
    background: var(--surface);
}

/* Hero 区域 */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    opacity: 0.1;
    z-index: -1;
}

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

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    line-height: 1.8;
}

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

.btn {
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 0.75rem;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--border);
    transform: translateY(-2px);
}

/* 统计区域 */
.stats-section {
    padding: 4rem 0;
    background: var(--surface);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    text-align: center;
}

.stat-item {
    padding: 2rem;
}

.stat-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 1.1rem;
    color: var(--text-muted);
}

/* 功能区域 */
.features-section {
    padding: 6rem 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
}

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

.feature-card {
    background: var(--surface);
    padding: 2.5rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.feature-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.feature-description {
    color: var(--text-muted);
    line-height: 1.7;
}

/* 关于我们 */
.about-section {
    padding: 6rem 0;
    background: var(--surface);
}

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

.about-content h2 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
}

.about-content p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    color: var(--text-muted);
    line-height: 1.8;
}

/* 页脚 */
.footer {
    background: var(--background);
    border-top: 1px solid var(--border);
    padding: 3rem 0;
    text-align: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-tagline {
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.footer-copyright {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .nav-menu {
        display: none;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 200px;
    }
}