/* 全局重置与基础 */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif; background: #f5f7fa; color: #1a1a2e; line-height: 1.6; transition: background 0.3s, color 0.3s; }
body.dark-mode { background: #0f0f1a; color: #e0e0e0; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img, svg { max-width: 100%; height: auto; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* 品牌色系统 */
:root { --primary: #1a2a6c; --secondary: #b21f1f; --accent: #fdbb2d; --glass-bg: rgba(255,255,255,0.3); --glass-border: rgba(255,255,255,0.18); --shadow: 0 8px 32px rgba(0,0,0,0.1); --radius: 20px; --transition: 0.3s ease; }
body.dark-mode { --primary: #2d3a7a; --secondary: #c0392b; --accent: #f1c40f; --glass-bg: rgba(20,20,40,0.5); --glass-border: rgba(255,255,255,0.1); --shadow: 0 8px 32px rgba(0,0,0,0.5); }

/* 导航 */
.navbar { position: fixed; top: 0; left: 0; width: 100%; z-index: 1000; background: rgba(255,255,255,0.85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid rgba(0,0,0,0.05); transition: background 0.3s, box-shadow 0.3s; }
body.dark-mode .navbar { background: rgba(15,15,26,0.85); border-bottom: 1px solid rgba(255,255,255,0.05); }
.navbar.scrolled { box-shadow: 0 4px 20px rgba(0,0,0,0.1); }
.nav-container { display: flex; align-items: center; justify-content: space-between; padding: 12px 24px; max-width: 1200px; margin: 0 auto; }
.nav-logo { font-size: 1.6rem; font-weight: 800; background: linear-gradient(135deg, var(--primary), var(--secondary)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.nav-links { display: flex; gap: 28px; }
.nav-links a { font-weight: 500; padding: 6px 0; border-bottom: 2px solid transparent; transition: border-color 0.3s, color 0.3s; }
.nav-links a:hover, .nav-links a.active { border-bottom-color: var(--secondary); color: var(--secondary); }
.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; background: none; border: none; padding: 4px; }
.nav-toggle span { width: 26px; height: 3px; background: var(--primary); border-radius: 4px; transition: 0.3s; }
body.dark-mode .nav-toggle span { background: #e0e0e0; }
.nav-actions { display: flex; align-items: center; gap: 16px; }
.dark-toggle { background: none; border: 1px solid var(--primary); border-radius: 30px; padding: 6px 14px; font-size: 0.85rem; cursor: pointer; transition: 0.3s; color: var(--primary); }
body.dark-mode .dark-toggle { border-color: #e0e0e0; color: #e0e0e0; }
.dark-toggle:hover { background: var(--primary); color: #fff; }
body.dark-mode .dark-toggle:hover { background: #e0e0e0; color: #0f0f1a; }

/* 移动菜单 */
.mobile-menu { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.6); backdrop-filter: blur(8px); z-index: 999; flex-direction: column; justify-content: center; align-items: center; gap: 24px; }
.mobile-menu.open { display: flex; }
.mobile-menu a { font-size: 1.5rem; color: #fff; font-weight: 600; padding: 8px 0; border-bottom: 2px solid transparent; }
.mobile-menu a:hover { border-bottom-color: var(--accent); }
.mobile-close { position: absolute; top: 20px; right: 30px; font-size: 2.2rem; color: #fff; cursor: pointer; background: none; border: none; }

/* Hero Banner */
.hero { padding: 140px 20px 80px; background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 50%, var(--accent) 100%); color: #fff; text-align: center; position: relative; overflow: hidden; }
.hero::before { content: ''; position: absolute; inset: 0; background: radial-gradient(circle at 20% 30%, rgba(255,255,255,0.1) 0%, transparent 60%); pointer-events: none; }
.hero h1 { font-size: 3.2rem; font-weight: 800; margin-bottom: 20px; line-height: 1.2; }
.hero p { font-size: 1.3rem; max-width: 700px; margin: 0 auto 30px; opacity: 0.9; }
.hero-buttons { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; }
.btn { padding: 14px 36px; border-radius: 50px; font-weight: 600; border: none; cursor: pointer; transition: 0.3s; font-size: 1rem; }
.btn-primary { background: #fff; color: var(--primary); box-shadow: 0 4px 14px rgba(0,0,0,0.2); }
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(0,0,0,0.3); }
.btn-outline { background: transparent; border: 2px solid #fff; color: #fff; }
.btn-outline:hover { background: #fff; color: var(--primary); }
.hero-carousel { margin-top: 40px; position: relative; }
.carousel-track { display: flex; gap: 20px; overflow: hidden; justify-content: center; }
.carousel-item { min-width: 260px; background: var(--glass-bg); backdrop-filter: blur(8px); border: 1px solid var(--glass-border); border-radius: var(--radius); padding: 30px; color: #fff; text-align: left; transition: 0.3s; }
.carousel-item:hover { transform: translateY(-6px); }
.carousel-item svg { width: 48px; height: 48px; margin-bottom: 12px; fill: #fff; }
.carousel-item h3 { font-size: 1.3rem; margin-bottom: 8px; }
.carousel-item p { font-size: 0.9rem; opacity: 0.85; }

/* 通用section */
.section { padding: 80px 20px; }
.section-title { font-size: 2.4rem; font-weight: 700; text-align: center; margin-bottom: 16px; position: relative; }
.section-title::after { content: ''; display: block; width: 60px; height: 4px; background: linear-gradient(90deg, var(--primary), var(--secondary)); margin: 12px auto 0; border-radius: 4px; }
.section-sub { text-align: center; max-width: 700px; margin: 0 auto 50px; color: #555; }
body.dark-mode .section-sub { color: #aaa; }

/* 卡片网格 */
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 30px; }
.card { background: var(--glass-bg); backdrop-filter: blur(8px); border: 1px solid var(--glass-border); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow); transition: 0.3s; }
.card:hover { transform: translateY(-6px); box-shadow: 0 12px 40px rgba(0,0,0,0.15); }
.card svg { width: 48px; height: 48px; margin-bottom: 16px; }
.card h3 { font-size: 1.4rem; margin-bottom: 12px; }
.card p { color: #555; font-size: 0.95rem; }
body.dark-mode .card p { color: #bbb; }

/* 品牌故事 */
.brand-story { display: flex; flex-wrap: wrap; gap: 40px; align-items: center; }
.brand-story-text { flex: 1; min-width: 280px; }
.brand-story-text h2 { font-size: 2rem; margin-bottom: 20px; }
.brand-story-text p { margin-bottom: 16px; }
.brand-story-visual { flex: 1; min-width: 280px; text-align: center; }
.brand-story-visual svg { width: 100%; max-width: 400px; height: auto; }

/* 数字统计 */
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 30px; text-align: center; margin: 50px 0; }
.stat-item { padding: 20px; }
.stat-number { font-size: 2.8rem; font-weight: 800; background: linear-gradient(135deg, var(--primary), var(--secondary)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.stat-label { font-size: 1rem; margin-top: 6px; color: #666; }
body.dark-mode .stat-label { color: #aaa; }

/* 时间线 */
.timeline { position: relative; padding-left: 40px; }
.timeline::before { content: ''; position: absolute; left: 18px; top: 0; bottom: 0; width: 4px; background: linear-gradient(180deg, var(--primary), var(--secondary)); border-radius: 4px; }
.timeline-item { margin-bottom: 40px; position: relative; }
.timeline-item::before { content: ''; position: absolute; left: -32px; top: 6px; width: 16px; height: 16px; background: var(--secondary); border-radius: 50%; border: 3px solid #fff; box-shadow: 0 0 0 3px var(--primary); }
body.dark-mode .timeline-item::before { border-color: #0f0f1a; }
.timeline-year { font-weight: 700; font-size: 1.2rem; color: var(--secondary); }
.timeline-text { margin-top: 4px; }

/* FAQ */
.faq-item { border-bottom: 1px solid rgba(0,0,0,0.08); padding: 18px 0; cursor: pointer; }
body.dark-mode .faq-item { border-bottom-color: rgba(255,255,255,0.08); }
.faq-question { display: flex; justify-content: space-between; align-items: center; font-weight: 600; font-size: 1.1rem; }
.faq-question span { transition: 0.3s; }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.4s ease, padding 0.3s; padding-top: 0; color: #555; }
body.dark-mode .faq-answer { color: #bbb; }
.faq-item.open .faq-answer { max-height: 300px; padding-top: 14px; }
.faq-item.open .faq-question span { transform: rotate(180deg); }

/* 页脚 */
.footer { background: var(--primary); color: #fff; padding: 60px 20px 30px; }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 40px; }
.footer h4 { font-size: 1.2rem; margin-bottom: 16px; border-bottom: 2px solid var(--accent); display: inline-block; padding-bottom: 6px; }
.footer a { color: rgba(255,255,255,0.8); display: block; margin-bottom: 8px; transition: 0.3s; }
.footer a:hover { color: var(--accent); padding-left: 4px; }
.footer-bottom { margin-top: 40px; border-top: 1px solid rgba(255,255,255,0.2); padding-top: 20px; text-align: center; font-size: 0.9rem; opacity: 0.8; }

/* 返回顶部 */
.back-to-top { position: fixed; bottom: 30px; right: 30px; background: var(--secondary); color: #fff; width: 50px; height: 50px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 1.6rem; cursor: pointer; border: none; box-shadow: 0 4px 14px rgba(0,0,0,0.3); opacity: 0; visibility: hidden; transition: 0.3s; z-index: 999; }
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: scale(1.1); }

/* 滚动动画 */
.fade-in { opacity: 0; transform: translateY(30px); transition: opacity 0.7s ease, transform 0.7s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* 响应式 */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-toggle { display: flex; }
    .hero h1 { font-size: 2.2rem; }
    .hero p { font-size: 1rem; }
    .section-title { font-size: 1.8rem; }
    .brand-story { flex-direction: column; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
    .hero { padding: 120px 16px 60px; }
    .hero h1 { font-size: 1.8rem; }
    .btn { padding: 12px 24px; font-size: 0.9rem; }
    .footer-grid { grid-template-columns: 1fr; }
}