/* 汉驰自动变速箱 - 独立样式系统 */
/* 风格：汽车后市场专业，深蓝+灰色+橙色点缀 */
* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
  --primary: #1e3a5f;
  --primary-dark: #0f2744;
  --secondary: #f97316;
  --secondary-dark: #ea580c;
  --accent: #fbbf24;
  --bg: #f8fafc;
  --bg-card: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --shadow: 0 4px 20px rgba(30, 58, 95, 0.1);
  --shadow-hover: 0 8px 30px rgba(30, 58, 95, 0.18);
  --radius: 12px;
}
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif; background: var(--bg); color: var(--text); line-height: 1.7; }
a { text-decoration: none; color: inherit; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* 导航栏 */
.navbar { position: sticky; top: 0; z-index: 100; background: rgba(30,58,95,0.98); backdrop-filter: blur(10px); border-bottom: 3px solid var(--secondary); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; padding: 14px 0; }
.logo { display: flex; align-items: center; gap: 12px; }
.logo-icon { width: 48px; height: 48px; background: linear-gradient(135deg, var(--secondary), var(--accent)); border-radius: 8px; display: flex; align-items: center; justify-content: center; font-size: 24px; box-shadow: 0 4px 12px rgba(249,115,22,0.4); }
.logo-title { font-size: 20px; font-weight: 800; color: white; }
.logo-sub { font-size: 12px; color: #94a3b8; }
.nav-links { display: flex; list-style: none; gap: 4px; align-items: center; flex: 1; justify-content: center; }
.nav-links a { padding: 8px 14px; border-radius: 6px; font-size: 14px; font-weight: 500; color: #cbd5e1; transition: all 0.2s; white-space: nowrap; }
.nav-links a:hover, .nav-links a.active { background: var(--secondary); color: white; }
.nav-cta { background: linear-gradient(135deg, var(--secondary), var(--secondary-dark)) !important; color: white !important; font-weight: 600 !important; }
.mobile-toggle { display: none; background: none; border: none; font-size: 24px; cursor: pointer; color: white; }

/* Hero */
.hero { background: linear-gradient(135deg, #0f2744 0%, #1e3a5f 50%, #334155 100%); padding: 80px 0; position: relative; overflow: hidden; color: white; }
.hero::before { content: "🔧"; position: absolute; font-size: 200px; opacity: 0.05; right: 5%; top: 10%; }
.hero h1 { font-size: 42px; font-weight: 800; line-height: 1.3; margin-bottom: 20px; }
.hero h1 span { color: var(--secondary); }
.hero p { font-size: 18px; color: #cbd5e1; margin-bottom: 30px; max-width: 600px; }
.hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
.btn { display: inline-block; padding: 14px 32px; border-radius: 6px; font-size: 16px; font-weight: 600; cursor: pointer; border: none; transition: all 0.3s; }
.btn-primary { background: linear-gradient(135deg, var(--secondary), var(--secondary-dark)); color: white; box-shadow: 0 4px 15px rgba(249,115,22,0.4); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(249,115,22,0.5); }
.btn-secondary { background: transparent; color: white; border: 2px solid #475569; }
.btn-secondary:hover { border-color: var(--secondary); color: var(--secondary); }
.hero-stats { display: flex; gap: 40px; margin-top: 50px; flex-wrap: wrap; }
.stat-item h3 { font-size: 36px; font-weight: 800; color: var(--secondary); }
.stat-item p { font-size: 14px; color: #94a3b8; }

/* 通用区块 */
.section { padding: 70px 0; }
.section-title { text-align: center; margin-bottom: 50px; }
.section-title h2 { font-size: 32px; font-weight: 800; margin-bottom: 12px; }
.section-title h2 span { color: var(--secondary); }
.section-title p { font-size: 16px; color: var(--text-muted); }

/* 卡片 */
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr)); gap: 24px; }
.card { background: var(--bg-card); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow); transition: all 0.3s; border-top: 4px solid var(--secondary); }
.card:hover { transform: translateY(-5px); box-shadow: var(--shadow-hover); }
.card-icon { font-size: 40px; margin-bottom: 16px; }
.card h3 { font-size: 20px; font-weight: 700; margin-bottom: 12px; color: var(--primary); }
.card p { font-size: 14px; color: var(--text-muted); line-height: 1.7; }

/* 高亮框 */
.highlight-box { background: linear-gradient(135deg, #eff6ff, #dbeafe); border-left: 4px solid var(--primary); padding: 20px 24px; border-radius: 0 8px 8px 0; margin-bottom: 16px; }
.highlight-box.orange { background: linear-gradient(135deg, #fff7ed, #ffedd5); border-left-color: var(--secondary); }
.highlight-box p { font-size: 15px; line-height: 1.8; }
.highlight-box strong { color: var(--primary-dark); }

/* 故障卡片 */
.fault-card { background: white; border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); border-left: 4px solid var(--secondary); margin-bottom: 16px; }
.fault-card h4 { font-size: 18px; font-weight: 700; color: var(--primary); margin-bottom: 8px; }
.fault-card .symptom { font-size: 14px; color: var(--secondary-dark); font-weight: 600; margin-bottom: 8px; }
.fault-card .solution { font-size: 14px; color: var(--text-muted); }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { background: white; border-radius: 8px; margin-bottom: 12px; box-shadow: var(--shadow); overflow: hidden; border-left: 4px solid var(--secondary); }
.faq-question { padding: 20px 24px; cursor: pointer; font-weight: 600; font-size: 16px; display: flex; justify-content: space-between; align-items: center; }
.faq-question .arrow { transition: transform 0.3s; color: var(--secondary); }
.faq-item[open] .arrow { transform: rotate(180deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s; padding: 0 24px; }
.faq-item[open] .faq-answer { max-height: none; padding: 0 24px 20px; }
.faq-answer p { font-size: 15px; color: var(--text-muted); line-height: 1.8; }

/* 案例 */
.case-card { background: white; border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); transition: all 0.3s; cursor: pointer; border-top: 4px solid var(--secondary); }
.case-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-hover); }
.case-header { background: linear-gradient(135deg, var(--primary), var(--primary-dark)); padding: 24px; color: white; }
.case-header h3 { font-size: 20px; font-weight: 700; }
.case-header .case-tag { display: inline-block; background: var(--secondary); padding: 4px 12px; border-radius: 4px; font-size: 12px; margin-top: 8px; }
.case-body { padding: 24px; }
.case-body p { font-size: 14px; color: var(--text-muted); margin-bottom: 12px; }
.case-meta { display: flex; gap: 16px; font-size: 12px; color: var(--text-muted); margin-top: 16px; flex-wrap: wrap; }

/* 页脚 */
.footer { background: linear-gradient(135deg, #0f2744, #020617); color: white; padding: 50px 0 20px; }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 30px; margin-bottom: 30px; }
.footer h4 { font-size: 16px; margin-bottom: 16px; color: var(--secondary); }
.footer ul { list-style: none; }
.footer li { margin-bottom: 8px; font-size: 14px; color: #94a3b8; }
.footer a:hover { color: var(--secondary); }
.footer-bottom { text-align: center; padding-top: 20px; border-top: 1px solid #1e3a5f; font-size: 13px; color: #64748b; }

/* 响应式 */
@media (max-width: 768px) {
  .nav-links { display: none; position: absolute; top: 100%; left: 0; right: 0; background: var(--primary); flex-direction: column; padding: 20px; }
  .nav-links.open { display: flex; }
  .mobile-toggle { display: block; }
  .hero h1 { font-size: 28px; }
  .hero-stats { gap: 20px; }
  .stat-item h3 { font-size: 28px; }
  .section { padding: 50px 0; }
}

/* 可访问的交互控件 */
.faq-question { width: 100%; border: 0; background: transparent; text-align: left; font-family: inherit; color: inherit; gap: 12px; }
.faq-question:focus-visible, .mobile-toggle:focus-visible { outline: 3px solid var(--primary); outline-offset: 3px; }
.faq-question .arrow { flex-shrink: 0; }

/* Native disclosure remains operable when JavaScript is unavailable. */
.faq-question { list-style: none; }
.faq-question::-webkit-details-marker { display: none; }