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

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #6366f1;
    --accent: #f59e0b;
    --dark: #0f172a;
    --light: #f8fafc;
    --gray: #64748b;
    --gray-light: #e2e8f0;
    --gradient: linear-gradient(135deg, #2563eb, #6366f1);
    --shadow: 0 4px 20px rgba(0,0,0,0.08);
    --shadow-hover: 0 8px 30px rgba(37,99,235,0.15);
    --radius: 12px;
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
    color: var(--dark);
    background: var(--light);
    line-height: 1.6;
    overflow-x: hidden;
}

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

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--gray-light);
    z-index: 1000;
    padding: 15px 0;
    transition: var(--transition);
}

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

.logo a {
    font-size: 24px;
    font-weight: 800;
    color: var(--dark);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--gradient);
    border-radius: 8px;
    color: white;
    font-size: 18px;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 8px;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--gray);
    font-weight: 500;
    padding: 8px 16px;
    border-radius: 8px;
    transition: var(--transition);
    font-size: 15px;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary);
    background: rgba(37,99,235,0.08);
}

.btn-login {
    background: var(--gradient) !important;
    color: white !important;
    padding: 10px 24px !important;
    border-radius: 8px !important;
}

.btn-login:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

.hamburger {
    display: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--dark);
}

/* ===== Hero ===== */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0e7ff 50%, #fdf4ff 100%);
    position: relative;
    overflow: hidden;
}

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

.hero-content h1 {
    font-size: 48px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
}

.highlight {
    display: block;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 18px;
    color: var(--gray);
    margin-bottom: 32px;
    line-height: 1.8;
}

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

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: 10px;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    font-size: 16px;
}

.btn-primary {
    background: var(--gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(37,99,235,0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(37,99,235,0.4);
}

.btn-secondary {
    background: white;
    color: var(--primary);
    border: 2px solid var(--gray-light);
}

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

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-placeholder {
    width: 400px;
    height: 400px;
    background: var(--gradient);
    border-radius: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 80px;
    gap: 20px;
    box-shadow: 0 20px 60px rgba(37,99,235,0.3);
    animation: float 6s ease-in-out infinite;
}

.hero-placeholder span {
    font-size: 32px;
    font-weight: 800;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

/* ===== 功能概览 ===== */
.features-overview {
    padding: 100px 0;
    background: white;
}

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

.section-title h2 {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 12px;
}

.section-title p {
    color: var(--gray);
    font-size: 18px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-card {
    background: var(--light);
    border-radius: var(--radius);
    padding: 36px 28px;
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--gray-light);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
    border-color: transparent;
}

.feature-icon {
    width: 64px;
    height: 64px;
    background: var(--gradient);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    color: white;
    font-size: 26px;
}

.feature-card h3 {
    font-size: 20px;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--gray);
    font-size: 15px;
    line-height: 1.7;
}

/* ===== 统计信息 ===== */
.stats {
    padding: 80px 0;
    background: var(--gradient);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.stat-item {
    text-align: center;
    color: white;
}

.stat-number {
    display: block;
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 8px;
}

.stat-label {
    font-size: 18px;
    opacity: 0.9;
}

/* ===== 最新动态 ===== */
.news {
    padding: 100px 0;
    background: var(--light);
}

.news-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.news-item {
    background: white;
    border-radius: var(--radius);
    padding: 28px;
    display: flex;
    gap: 24px;
    transition: var(--transition);
    border: 1px solid var(--gray-light);
}

.news-item:hover {
    transform: translateX(8px);
    box-shadow: var(--shadow);
}

.news-date {
    flex-shrink: 0;
    background: var(--gradient);
    color: white;
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    height: fit-content;
}

.news-content h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.news-content p {
    color: var(--gray);
    font-size: 15px;
}

/* ===== 页脚 ===== */
.footer {
    background: var(--dark);
    color: white;
    padding: 60px 0 0;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    font-size: 18px;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--primary);
    display: inline-block;
}

.footer-col p {
    color: #94a3b8;
    font-size: 14px;
    line-height: 1.8;
}

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

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col ul li a {
    color: #94a3b8;
    text-decoration: none;
    transition: var(--transition);
    font-size: 14px;
}

.footer-col ul li a:hover {
    color: white;
    padding-left: 4px;
}

.footer-col ul li i {
    margin-right: 8px;
    color: var(--primary);
    width: 16px;
}

.footer-bottom {
    border-top: 1px solid #1e293b;
    padding: 20px 0;
    text-align: center;
    color: #475569;
    font-size: 14px;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow);
        border-bottom: 1px solid var(--gray-light);
    }
    .nav-links.active {
        display: flex;
    }
    .hamburger {
        display: block;
    }
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    .hero-content h1 {
        font-size: 32px;
    }
    .hero-btns {
        justify-content: center;
    }
    .hero-placeholder {
        width: 280px;
        height: 280px;
        font-size: 50px;
    }
    .hero-placeholder span {
        font-size: 22px;
    }
    .features-grid {
        grid-template-columns: 1fr;
    }
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
    .stat-number {
        font-size: 36px;
    }
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    .news-item {
        flex-direction: column;
    }
}