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

:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9ff;
    --bg-gradient-start: #f5f0ff;
    --bg-gradient-end: #ffffff;
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --primary-glow: rgba(99, 102, 241, 0.15);
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --text-tertiary: #9ca3af;
    --border: #e5e7eb;
    --card-bg: #ffffff;
    --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);
}

[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-gradient-start: #0f172a;
    --bg-gradient-end: #1e1b4b;
    --primary: #818cf8;
    --primary-dark: #6366f1;
    --primary-light: #a5b4fc;
    --primary-glow: rgba(129, 140, 248, 0.2);
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #94a3b8;
    --border: #334155;
    --card-bg: #1e293b;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: background 0.3s, color 0.3s;
    overflow-x: hidden;
}

/* 导航栏 */
.navbar { position: fixed; top: 0; width: 100%; background: rgba(255, 255, 255, 0.8); backdrop-filter: blur(12px); border-bottom: 1px solid var(--border); z-index: 1000; transition: all 0.3s; }
[data-theme="dark"] .navbar { background: rgba(15, 23, 42, 0.8); }
.container { max-width: 1280px; margin: 0 auto; padding: 0 32px; }
.nav-container { display: flex; justify-content: space-between; align-items: center; height: 70px; }
.logo-section { display: flex; align-items: center; gap: 12px; cursor: pointer; }
.logo-img { height: 40px; width: auto; }
.logo-text { font-size: 24px; font-weight: 700; background: linear-gradient(135deg, var(--primary), var(--primary-light)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.logo-badge { font-size: 11px; background: var(--primary); color: white; padding: 2px 8px; border-radius: 20px; font-weight: 500; }
.nav-menu { display: flex; gap: 8px; list-style: none; flex-wrap: wrap; }
.nav-link { position: relative; padding: 8px 16px; text-decoration: none; color: var(--text-secondary); font-weight: 500; transition: color 0.3s; cursor: pointer; }
.nav-link:hover, .nav-link.active { color: var(--primary); }
.nav-link.active::after { content: ''; position: absolute; bottom: -2px; left: 16px; right: 16px; height: 2px; background: var(--primary); border-radius: 2px; }
.nav-right { display: flex; align-items: center; gap: 16px; }
.theme-toggle, .lang-toggle { cursor: pointer; padding: 8px; border-radius: 8px; transition: all 0.3s; color: var(--text-secondary); }
.theme-toggle:hover, .lang-toggle:hover { background: var(--border); color: var(--primary); }
.btn-login, .btn-register { padding: 8px 20px; border-radius: 8px; cursor: pointer; transition: all 0.3s; font-weight: 500; border: none; }
.btn-login { border: 1px solid var(--primary); background: transparent; color: var(--primary); }
.btn-login:hover { background: var(--primary); color: white; transform: translateY(-2px); }
.btn-register { background: var(--primary); color: white; }
.btn-register:hover { background: var(--primary-dark); transform: translateY(-2px); }
.user-info { display: flex; align-items: center; gap: 12px; background: var(--border); padding: 6px 16px; border-radius: 40px; cursor: pointer; }
.user-info span { color: var(--text-primary); }

/* Hero区域 */
.hero { padding: 140px 0 80px; position: relative; overflow: hidden; background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 50%, var(--bg-gradient-start) 100%); }
.hero::before { content: ''; position: absolute; top: 0; left: 0; right: 0; bottom: 0; background: radial-gradient(circle at 20% 50%, var(--primary-glow) 0%, transparent 50%); pointer-events: none; }
.hero-content { text-align: center; max-width: 900px; margin: 0 auto; position: relative; z-index: 1; }
.hero-badge { display: inline-flex; align-items: center; gap: 8px; background: var(--primary-glow); backdrop-filter: blur(10px); border: 1px solid var(--primary); padding: 8px 20px; border-radius: 100px; font-size: 14px; font-weight: 500; color: var(--primary); margin-bottom: 32px; animation: pulse 2s infinite; }
@keyframes pulse { 0%, 100% { opacity: 1; transform: scale(1); } 50% { opacity: 0.8; transform: scale(1.05); } }
.hero-title { font-size: 64px; font-weight: 800; line-height: 1.2; margin-bottom: 24px; background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary) 50%, var(--primary-light) 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.hero-subtitle { font-size: 20px; color: var(--text-secondary); margin-bottom: 40px; line-height: 1.6; }
.hero-buttons { display: flex; gap: 20px; justify-content: center; margin-bottom: 60px; }
.btn-primary { padding: 14px 36px; background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: white; border: none; border-radius: 12px; font-size: 16px; font-weight: 600; cursor: pointer; transition: all 0.3s; box-shadow: 0 4px 15px var(--primary-glow); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 25px var(--primary-glow); }
.btn-secondary { padding: 14px 36px; background: transparent; border: 2px solid var(--primary); color: var(--primary); border-radius: 12px; font-size: 16px; font-weight: 600; cursor: pointer; transition: all 0.3s; }
.btn-secondary:hover { background: var(--primary); color: white; transform: translateY(-2px); }
.stats { display: flex; justify-content: center; gap: 64px; flex-wrap: wrap; }
.stat-item { text-align: center; animation: fadeInUp 0.6s ease-out; }
@keyframes fadeInUp { from { opacity: 0; transform: translateY(30px); } to { opacity: 1; transform: translateY(0); } }
.stat-number { font-size: 40px; font-weight: 800; background: linear-gradient(135deg, var(--primary), var(--primary-light)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.stat-label { color: var(--text-tertiary); margin-top: 8px; font-size: 14px; }

/* 页面切换动画 & 通用区域 */
.page-transition { animation: slideIn 0.5s ease-out; }
@keyframes slideIn { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
.section { padding: 80px 0; }
.section-title { text-align: center; font-size: 36px; margin-bottom: 16px; }
.section-subtitle { text-align: center; color: var(--text-secondary); margin-bottom: 48px; }

/* 各种网格布局 (Features, Products, Models, Docs) */
.features-grid, .product-grid, .models-grid, .docs-grid { display: grid; gap: 32px; }
.features-grid { grid-template-columns: repeat(auto-fit, minmax(350px, 1fr)); }
.product-grid { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.models-grid { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 24px; }
.docs-grid { grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 24px; }

.feature-card, .product-card, .model-card, .doc-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 20px; padding: 32px; transition: all 0.3s; cursor: pointer; }
.feature-card:hover, .product-card:hover, .model-card:hover, .doc-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--primary); }
.model-card, .doc-card { border-radius: 16px; padding: 24px; }
.doc-card { padding: 32px; text-align: center; }

.feature-icon, .product-icon { width: 56px; height: 56px; background: var(--primary-glow); border-radius: 16px; display: flex; align-items: center; justify-content: center; margin-bottom: 24px; }
.product-icon { width: 60px; height: 60px; }
.feature-icon i, .product-icon i { font-size: 28px; color: var(--primary); }
.doc-icon { font-size: 48px; color: var(--primary); margin-bottom: 16px; }

.feature-card h3, .product-card h3 { font-size: 20px; margin-bottom: 12px; }
.product-card h3 { font-size: 22px; }
.doc-card h4 { font-size: 18px; margin-bottom: 8px; }

.feature-card p, .product-card p, .doc-card p { color: var(--text-secondary); line-height: 1.6; }
.product-card p { margin-bottom: 20px; }
.doc-card p { color: var(--text-tertiary); font-size: 14px; }

.product-features { list-style: none; margin-top: 20px; padding-top: 20px; border-top: 1px solid var(--border); }
.product-features li { margin-bottom: 10px; color: var(--text-tertiary); display: flex; align-items: center; gap: 8px; }
.product-features li i { color: var(--primary); font-size: 12px; }

/* 合作伙伴滚动栏 */
.partners-section { padding: 40px 0; background: var(--bg-secondary); border-bottom: 1px solid var(--border); }
.partners-wrapper { text-align: center; }
.partners-title { font-size: 14px; color: var(--text-tertiary); margin-bottom: 20px; letter-spacing: 2px; }
.partners-slider { overflow: hidden; position: relative; width: 100%; }
.partners-track { display: flex; animation: scroll 30s linear infinite; gap: 30px; }
@keyframes scroll { 0% { transform: translateX(0); } 100% { transform: translateX(-50%); } }
.partner-item { display: flex; align-items: center; gap: 8px; padding: 8px 24px; background: var(--card-bg); border: 1px solid var(--border); border-radius: 40px; font-weight: 500; color: var(--text-secondary); white-space: nowrap; transition: all 0.3s; }
.partner-item:hover { border-color: var(--primary); color: var(--primary); transform: scale(1.05); }

/* CTA区域 */
.cta { padding: 80px 0; text-align: center; background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: white; }

/* 模态框 (登录/注册) */
.modal { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.5); z-index: 2000; justify-content: center; align-items: center; }
.modal.active { display: flex; }
.modal-content { background: var(--card-bg); border-radius: 24px; padding: 40px; max-width: 450px; width: 90%; position: relative; border: 1px solid var(--border); }
.modal-close { position: absolute; top: 20px; right: 20px; cursor: pointer; font-size: 24px; color: var(--text-tertiary); }
.modal-title { font-size: 24px; margin-bottom: 24px; text-align: center; }
.form-group { margin-bottom: 20px; }
.form-group input { width: 100%; padding: 12px; border: 1px solid var(--border); border-radius: 8px; background: var(--bg-primary); color: var(--text-primary); }
.form-group input:focus { outline: none; border-color: var(--primary); }

/* 页脚 */
.footer { background: var(--bg-secondary); padding: 48px 0 24px; border-top: 1px solid var(--border); }
.footer-links { display: flex; justify-content: center; gap: 32px; margin-bottom: 24px; flex-wrap: wrap; }
.footer-links a { color: var(--text-tertiary); text-decoration: none; transition: color 0.3s; cursor: pointer; }
.footer-links a:hover { color: var(--primary); }

/* 响应式 */
@media (max-width: 768px) {
    .nav-menu { display: none; }
    .hero-title { font-size: 40px; }
    .hero-buttons { flex-direction: column; align-items: center; }
    .stats { gap: 32px; }
    .nav-right { gap: 8px; }
    .btn-login, .btn-register { padding: 6px 12px; font-size: 12px; }
}