/* ===== 全局重置 & 变量 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
    --primary: #1a6ef5;
    --primary-dark: #1558cc;
    --accent: #ff6b35;
    --text: #1a1a2e;
    --text-muted: #6b7280;
    --bg: #ffffff;
    --bg-soft: #f8fafc;
    --border: #e5e7eb;
    --radius: 12px;
    --shadow: 0 4px 24px rgba(0,0,0,.08);
    --nav-h: 64px;
    --font: 'PingFang SC', 'Microsoft YaHei', sans-serif;
}
html { scroll-behavior: smooth; }
body { font-family: var(--font); color: var(--text); background: var(--bg); padding-top: var(--nav-h); }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

/* ===== 导航栏 ===== */
.site-nav { position: fixed; top: 0; left: 0; right: 0; height: var(--nav-h); background: rgba(255,255,255,.95); backdrop-filter: blur(10px); border-bottom: 1px solid var(--border); z-index: 1000; }
.nav-inner { max-width: 1200px; margin: 0 auto; padding: 0 24px; height: 100%; display: flex; align-items: center; gap: 40px; }
.nav-brand { display: flex; align-items: center; gap: 8px; font-size: 20px; font-weight: 700; color: var(--primary); white-space: nowrap; }
.brand-icon { font-size: 22px; }
.nav-links { display: flex; align-items: center; gap: 4px; margin-left: auto; }
.nav-links > li { position: relative; }
.nav-links > li > a { display: flex; align-items: center; gap: 4px; padding: 8px 14px; border-radius: 8px; font-size: 15px; font-weight: 500; color: var(--text-muted); transition: all .2s; white-space: nowrap; }
.nav-links > li > a:hover, .nav-links > li > a.active { color: var(--primary); background: #f0f5ff; }
.dropdown-arrow { font-size: 11px; transition: transform .2s; }
.has-dropdown:hover .dropdown-arrow { transform: rotate(180deg); }

/* 下拉菜单 */
.dropdown { 
  display: none; 
  position: absolute; 
  top: 100%; 
  left: 0; 
  background: #fff; 
  border: 1px solid var(--border); 
  border-radius: var(--radius); 
  box-shadow: var(--shadow); 
  min-width: 140px; 
  padding: 8px 0; 
  z-index: 100;
  margin-top: 4px;
}

/* 在下拉菜单上方添加透明区域，防止鼠标移动时失去hover */
.dropdown::before {
  content: '';
  position: absolute;
  top: -4px;
  left: 0;
  right: 0;
  height: 4px;
  background: transparent;
}

.has-dropdown:hover .dropdown { display: block; }
.dropdown li a { display: block; padding: 10px 18px; font-size: 14px; color: var(--text-muted); transition: all .15s; }
.dropdown li a:hover { color: var(--primary); background: #f0f5ff; }

/* 移动端汉堡按钮 */
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 4px; margin-left: auto; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: all .2s; }

/* ===== 页脚 ===== */
.site-footer { background: #0f172a; color: #94a3b8; margin-top: 80px; }
.footer-inner { max-width: 1200px; margin: 0 auto; padding: 60px 24px 40px; display: grid; grid-template-columns: 2fr 1fr 1fr 1.2fr; gap: 40px; }
.footer-brand { font-size: 20px; font-weight: 700; color: #fff; display: flex; align-items: center; gap: 8px; margin-bottom: 12px; }
.footer-desc { font-size: 14px; margin-bottom: 20px; line-height: 1.6; }
.footer-contact { display: flex; flex-direction: column; gap: 8px; font-size: 14px; }
.footer-contact div { display: flex; align-items: center; gap: 8px; }
.footer-contact-wechat { align-items: flex-start; }
.footer-contact-wechat-qr img { width: 98px; height: 98px; border-radius: 12px; background: #fff; padding: 4px; border: 1px solid rgba(255,255,255,.18); }
.footer-col h4 { color: #fff; font-size: 15px; margin-bottom: 16px; }
.footer-col ul { display: flex; flex-direction: column; gap: 10px; }
.footer-col ul a { font-size: 14px; transition: color .2s; }
.footer-col ul a:hover { color: #fff; }
.footer-qr img { width: 120px; height: 120px; border-radius: 8px; background: #fff; padding: 4px; margin-bottom: 8px; }
.footer-qr p { font-size: 13px; }
.footer-bottom { border-top: 1px solid #1e293b; text-align: center; padding: 20px 24px; font-size: 13px; }

/* ===== 通用布局 ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-sm { padding: 48px 0; }
.section-header { text-align: center; margin-bottom: 48px; }
.section-header h2 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.section-header p { font-size: 17px; color: var(--text-muted); }

/* ===== Banner ===== */
.page-banner { position: relative; height: 420px; background: linear-gradient(135deg, #0f172a 0%, #1a3a6e 100%); display: flex; align-items: center; overflow: hidden; }
.page-banner::before { content: ''; position: absolute; inset: 0; background: url('') center/cover no-repeat; opacity: .3; }
.banner-content { position: relative; z-index: 1; max-width: 1200px; margin: 0 auto; padding: 0 24px; color: #fff; }
.banner-content h1 { font-size: 48px; font-weight: 800; margin-bottom: 16px; line-height: 1.2; }
.banner-content p { font-size: 20px; opacity: .85; }

/* ===== 按钮 ===== */
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 28px; border-radius: 8px; font-size: 15px; font-weight: 600; cursor: pointer; border: none; transition: all .2s; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(26,110,245,.35); }
.btn-outline { background: transparent; color: var(--primary); border: 2px solid var(--primary); }
.btn-outline:hover { background: var(--primary); color: #fff; }
.btn-accent { background: var(--accent); color: #fff; }
.btn-accent:hover { background: #e55a28; }
.btn-lg { padding: 16px 36px; font-size: 17px; border-radius: 10px; }

/* ===== 卡片 ===== */
.card { background: #fff; border-radius: var(--radius); border: 1px solid var(--border); overflow: hidden; transition: all .25s; }
.card:hover { box-shadow: var(--shadow); transform: translateY(-3px); }
.card-img { width: 100%; aspect-ratio: 16/9; object-fit: cover; background: var(--bg-soft); }
.card-body { padding: 20px; }
.card-title { font-size: 17px; font-weight: 600; margin-bottom: 8px; }
.card-text { font-size: 14px; color: var(--text-muted); line-height: 1.6; }

/* ===== 网格 ===== */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }

/* ===== 留资表单 ===== */
.lead-form { background: var(--bg-soft); border-radius: var(--radius); padding: 40px; }
.lead-form h3 { font-size: 24px; font-weight: 700; margin-bottom: 24px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-bottom: 16px; }
.form-group { display: flex; flex-direction: column; gap: 6px; margin-bottom: 16px; }
.form-group label { font-size: 14px; font-weight: 500; }
.form-group input, .form-group textarea, .form-group select { padding: 12px 16px; border: 1px solid var(--border); border-radius: 8px; font-size: 15px; font-family: var(--font); outline: none; transition: border-color .2s; }
.form-group input:focus, .form-group textarea:focus { border-color: var(--primary); }
.form-group textarea { resize: vertical; min-height: 100px; }
.form-msg { margin-top: 12px; font-size: 14px; padding: 10px 14px; border-radius: 6px; }
.form-msg.success { background: #f0fdf4; color: #16a34a; }
.form-msg.error { background: #fef2f2; color: #dc2626; }

/* ===== FAQ 折叠 ===== */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq-item { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.faq-q { display: flex; justify-content: space-between; align-items: center; padding: 18px 20px; cursor: pointer; font-weight: 600; font-size: 16px; background: #fff; transition: background .15s; }
.faq-q:hover { background: var(--bg-soft); }
.faq-q .faq-icon { font-size: 20px; transition: transform .2s; color: var(--primary); }
.faq-item.open .faq-icon { transform: rotate(45deg); }
.faq-a { display: none; padding: 0 20px 18px; font-size: 15px; color: var(--text-muted); line-height: 1.7; }
.faq-item.open .faq-a { display: block; }

/* ===== 响应式 ===== */
@media (max-width: 900px) {
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    .footer-inner { grid-template-columns: 1fr 1fr; }
    .banner-content h1 { font-size: 36px; }
}
@media (max-width: 640px) {
    .nav-links { display: none; flex-direction: column; position: absolute; top: var(--nav-h); left: 0; right: 0; background: #fff; border-bottom: 1px solid var(--border); padding: 16px; gap: 4px; }
    .nav-links.open { display: flex; }
    .nav-toggle { display: flex; }
    .dropdown { position: static; box-shadow: none; border: none; padding-left: 16px; }
    .has-dropdown:hover .dropdown { display: none; }
    .has-dropdown.open .dropdown { display: block; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .footer-inner { grid-template-columns: 1fr; gap: 32px; }
    .form-row { grid-template-columns: 1fr; }
    .banner-content h1 { font-size: 28px; }
    .section-header h2 { font-size: 26px; }
}