/* ========== CSS Variables & Reset ========== */
:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --primary-light: #e8f0fe;
  --accent: #fbbc04;
  --text: #202124;
  --text-secondary: #5f6368;
  --bg: #ffffff;
  --bg-alt: #f8f9fa;
  --border: #dadce0;
  --shadow: 0 1px 3px rgba(60,64,67,.15), 0 1px 2px rgba(60,64,67,.1);
  --shadow-hover: 0 4px 12px rgba(60,64,67,.2);
  --radius: 12px;
  --max-width: 1200px;
  --header-h: 64px;
  --transition: .25s ease;
}

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

html { scroll-behavior: smooth; font-size: 16px; overflow-x: hidden; }
body { overflow-x: hidden; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-wrap: break-word;
  word-break: break-word;
}

a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--primary-dark); }

img { max-width: 100%; display: block; }
ul, ol { list-style: none; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* ========== Header ========== */
.site-header {
  position: sticky; top: 0; z-index: 1000;
  background: rgba(255,255,255,.96);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  height: var(--header-h);
}

.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: var(--header-h);
}

.site-logo {
  display: flex; align-items: center; gap: 8px;
  font-size: 1.25rem; font-weight: 700; color: var(--text);
  white-space: nowrap;
}

.site-logo svg,
.site-logo .logo-img { width: auto; height: 32px; flex-shrink: 0; object-fit: contain; }
.site-logo:hover { color: var(--primary); }

.site-logo .logo-text { display: flex; flex-direction: column; line-height: 1.2; }
.site-logo .logo-slogan { font-size: .6rem; font-weight: 400; color: var(--text-secondary); letter-spacing: .5px; }

.main-nav { display: flex; gap: 4px; }

.main-nav a {
  padding: 8px 16px; border-radius: 8px;
  font-size: .925rem; color: var(--text-secondary); font-weight: 500;
  transition: background var(--transition), color var(--transition);
}

.main-nav a:hover,
.main-nav a.active {
  background: var(--primary-light); color: var(--primary);
}

.menu-toggle {
  display: none; background: none; border: none; cursor: pointer;
  padding: 6px; color: var(--text);
}
.menu-toggle svg { width: 24px; height: 24px; }

/* ========== Hero ========== */
.hero {
  background: linear-gradient(135deg, #1a73e8 0%, #4285f4 50%, #669df6 100%);
  color: #fff; padding: 80px 0 90px; text-align: center;
  position: relative; overflow: hidden;
}

.hero::after {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(circle at 30% 20%, rgba(255,255,255,.12) 0%, transparent 60%);
}

.hero .container { position: relative; z-index: 1; }
.hero h1 { font-size: 2.5rem; margin-bottom: 16px; font-weight: 800; letter-spacing: -0.5px; }
.hero p { font-size: 1.15rem; opacity: .92; max-width: 600px; margin: 0 auto 32px; }

/* ========== Section ========== */
.section { padding: 60px 0; }
.section-alt { background: var(--bg-alt); }

.section-title {
  font-size: 1.75rem; font-weight: 700; text-align: center;
  margin-bottom: 12px;
}

.section-subtitle {
  text-align: center; color: var(--text-secondary);
  margin-bottom: 40px; font-size: 1.05rem;
}

/* ========== Cards Grid ========== */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.cards-grid-3 { grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); }

.card {
  background: var(--bg); border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 28px; transition: box-shadow var(--transition), transform var(--transition);
  position: relative;
}

.card:hover { box-shadow: var(--shadow-hover); transform: translateY(-2px); }

.card h3 a::after {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 1;
}
.card:has(h3 a) { cursor: pointer; }

.card-icon {
  width: 48px; height: 48px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem; margin-bottom: 16px;
  background: var(--primary-light); color: var(--primary);
}

.card h3 { font-size: 1.15rem; margin-bottom: 8px; font-weight: 600; }
.card p { color: var(--text-secondary); font-size: .925rem; margin-bottom: 12px; }

.card-link {
  display: inline-flex; align-items: center; gap: 4px;
  font-size: .9rem; font-weight: 600;
}

.card-link::after { content: '→'; transition: transform var(--transition); }
.card-link:hover::after { transform: translateX(4px); }

/* ========== Category Cards ========== */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
}

.cat-card {
  display: flex; flex-direction: column; align-items: center;
  padding: 32px 16px; border-radius: var(--radius);
  border: 1px solid var(--border);
  text-align: center; transition: all var(--transition);
  background: var(--bg); color: var(--text);
}

.cat-card:hover { border-color: var(--primary); box-shadow: var(--shadow-hover); transform: translateY(-3px); }
.cat-card.cat-card-cta { border-color: var(--primary); background: linear-gradient(to bottom, rgba(26,115,232,.06), var(--bg)); }
.cat-card.cat-card-cta:hover { box-shadow: 0 6px 20px rgba(26,115,232,.2); }
.cat-card .cat-icon { font-size: 2rem; margin-bottom: 12px; }
.cat-card h3 { font-size: 1rem; font-weight: 600; }
.cat-card p { font-size: .8rem; color: var(--text-secondary); margin-top: 4px; }

/* ========== Breadcrumb ========== */
.breadcrumb {
  padding: 16px 0;
  font-size: .875rem; color: var(--text-secondary);
  display: flex; flex-wrap: wrap; gap: 4px;
}

.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb span { color: var(--text); }

/* ========== Page Banner ========== */
.page-banner {
  background: linear-gradient(135deg, #1a73e8 0%, #4285f4 100%);
  color: #fff; padding: 48px 0; text-align: center;
}

.page-banner h1 { font-size: 2rem; font-weight: 700; margin-bottom: 8px; }
.page-banner p { opacity: .9; font-size: 1.05rem; }

/* ========== Content Layout ========== */
.content-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 40px;
  padding: 40px 0;
}

.article-body { min-width: 0; }

.article-body h1 { font-size: 1.85rem; margin-bottom: 12px; line-height: 1.35; }
.article-body h2 { font-size: 1.4rem; margin: 36px 0 16px; padding-bottom: 8px; border-bottom: 2px solid var(--primary-light); }
.article-body h3 { font-size: 1.15rem; margin: 24px 0 12px; }
.article-body p { margin-bottom: 16px; }
.article-body ul, .article-body ol { margin: 12px 0 20px 20px; }
.article-body li { margin-bottom: 8px; list-style: disc; }
.article-body ol li { list-style: decimal; }

.article-meta {
  display: flex; gap: 16px; color: var(--text-secondary);
  font-size: .875rem; margin-bottom: 24px; flex-wrap: wrap;
}

.article-meta span { display: flex; align-items: center; gap: 4px; }

/* ========== Sidebar ========== */
.sidebar { position: sticky; top: 80px; align-self: start; }

.sidebar-block {
  background: var(--bg-alt); border-radius: var(--radius);
  padding: 24px; margin-bottom: 20px;
  border: 1px solid var(--border);
}

.sidebar-block h3 {
  font-size: 1.05rem; font-weight: 600;
  margin-bottom: 16px; padding-bottom: 8px;
  border-bottom: 2px solid var(--primary);
}

.sidebar-block ul li { margin-bottom: 10px; }
.sidebar-block ul li a { font-size: .9rem; color: var(--text-secondary); }
.sidebar-block ul li a:hover { color: var(--primary); }

/* ========== Table ========== */
.article-table { width: 100%; border-collapse: collapse; margin: 20px 0 28px; font-size: .925rem; }
.article-table th, .article-table td { padding: 12px 16px; border: 1px solid var(--border); text-align: left; }
.article-table th { background: var(--primary); color: #fff; font-weight: 600; }
.article-table tr:nth-child(even) { background: var(--bg-alt); }
.article-table tr:hover { background: var(--primary-light); }

.table-responsive { overflow-x: auto; margin: 20px 0; -webkit-overflow-scrolling: touch; }
.article-body table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; }

/* ========== FAQ ========== */
.faq-section { padding: 40px 0; }
.faq-section h2 { font-size: 1.5rem; margin-bottom: 24px; text-align: center; }

.faq-item {
  border: 1px solid var(--border); border-radius: var(--radius);
  margin-bottom: 12px; overflow: hidden;
}

.faq-question {
  width: 100%; background: none; border: none;
  padding: 18px 24px; text-align: left;
  font-size: 1rem; font-weight: 600; color: var(--text);
  cursor: pointer; display: flex; justify-content: space-between; align-items: center;
  transition: background var(--transition);
}

.faq-question:hover { background: var(--bg-alt); }

.faq-question::after {
  content: '+'; font-size: 1.3rem; color: var(--primary);
  transition: transform var(--transition);
}

.faq-item.active .faq-question::after { content: '−'; }
.faq-item.active .faq-question { background: var(--primary-light); color: var(--primary); }

.faq-answer { padding: 0 24px; max-height: 0; overflow: hidden; transition: max-height .35s ease, padding .35s ease; }
.faq-item.active .faq-answer { max-height: 600px; padding: 0 24px 20px; overflow-y: auto; }
.faq-answer p { color: var(--text-secondary); font-size: .925rem; line-height: 1.7; }
.faq-answer a { font-weight: 600; }

/* ========== Related Links ========== */
.related-links { padding: 32px 0; }
.related-links h3 { font-size: 1.2rem; margin-bottom: 16px; }

.related-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
}

.related-list a {
  display: block; padding: 14px 18px;
  background: var(--bg-alt); border-radius: 8px;
  border: 1px solid var(--border);
  font-size: .925rem; color: var(--text);
  transition: all var(--transition);
}

.related-list a:hover { border-color: var(--primary); background: var(--primary-light); color: var(--primary); }
.related-list a::before { content: '📄 '; }

/* ========== Update Info ========== */
.update-info {
  margin-top: 32px; padding: 16px 20px;
  background: var(--bg-alt); border-left: 3px solid var(--primary);
  border-radius: 0 8px 8px 0;
  font-size: .875rem; color: var(--text-secondary);
}

/* ========== QA Category Group ========== */
.qa-group { margin-bottom: 40px; }
.qa-group h2 {
  font-size: 1.35rem; margin-bottom: 20px;
  padding-left: 12px; border-left: 4px solid var(--primary);
}

.qa-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 16px; }

.qa-card {
  display: block; padding: 20px 24px;
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); transition: all var(--transition);
}

.qa-card:hover { border-color: var(--primary); box-shadow: var(--shadow-hover); transform: translateY(-2px); }
.qa-card h3 { font-size: 1.05rem; color: var(--text); margin-bottom: 6px; font-weight: 600; }
.qa-card p { font-size: .875rem; color: var(--text-secondary); }

/* ========== Knowledge Cards ========== */
.knowledge-card {
  background: var(--bg); border-radius: var(--radius);
  border: 1px solid var(--border); padding: 32px;
  transition: all var(--transition);
}

.knowledge-card:hover { box-shadow: var(--shadow-hover); transform: translateY(-2px); }
.knowledge-card .tag { display: inline-block; background: var(--primary-light); color: var(--primary); font-size: .78rem; padding: 3px 10px; border-radius: 20px; margin-bottom: 12px; font-weight: 600; }
.knowledge-card h3 { font-size: 1.15rem; margin-bottom: 8px; }
.knowledge-card p { color: var(--text-secondary); font-size: .9rem; }

/* ========== Footer ========== */
.site-footer {
  background: #1a1a2e; color: #ccc; padding: 48px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 32px; padding-bottom: 32px;
}

.footer-col h4 { color: #fff; margin-bottom: 16px; font-size: 1.05rem; }
.footer-col p { font-size: .9rem; line-height: 1.7; }
.footer-col ul li { margin-bottom: 8px; }
.footer-col ul li a { color: #aaa; font-size: .9rem; }
.footer-col ul li a:hover { color: #fff; }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.1);
  padding: 20px 0; text-align: center; font-size: .85rem;
}

.footer-bottom a { color: #aaa; }
.footer-bottom a:hover { color: #fff; }
.footer-bottom .beian { font-size: .78rem; color: #aaa; margin-top: 8px; }
.footer-bottom .beian a { color: #aaa; }

/* ========== CTA Section ========== */
.cta-section {
  background: linear-gradient(135deg, #1a73e8, #4285f4);
  color: #fff; padding: 60px 0; text-align: center;
}

.cta-section h2 { font-size: 1.75rem; margin-bottom: 12px; }
.cta-section p { opacity: .9; margin-bottom: 28px; font-size: 1.05rem; }

.btn-primary {
  display: inline-block; background: #fff; color: var(--primary);
  padding: 14px 36px; border-radius: 28px;
  font-weight: 700; font-size: 1rem;
  transition: all var(--transition);
}

.btn-primary:hover { background: var(--primary-light); transform: translateY(-2px); box-shadow: 0 4px 16px rgba(0,0,0,.2); }

/* ========== Card Grid (generic) ========== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
  margin-bottom: 40px;
}

/* ========== Solution Cards ========== */
.solutions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
  margin-bottom: 48px;
}

.solution-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: all var(--transition);
}

.solution-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

.solution-card .icon {
  font-size: 2rem;
  margin-bottom: 16px;
  display: block;
}

.solution-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.solution-card p {
  color: var(--text-secondary);
  font-size: .925rem;
}

/* ========== Contact Form ========== */
.contact-form {
  max-width: 640px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 6px;
  font-size: .925rem;
  color: var(--text);
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: .95rem;
  font-family: inherit;
  color: var(--text);
  background: var(--bg);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(26, 115, 232, .12);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 14px 36px;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  font-family: inherit;
}

.btn:hover {
  background: var(--primary-dark);
  box-shadow: 0 4px 12px rgba(26, 115, 232, .3);
  transform: translateY(-1px);
}

/* ========== Nav CTA Button ========== */
.main-nav .nav-cta {
  background: var(--primary);
  color: #fff !important;
  border-radius: 20px;
  padding: 8px 20px;
}

.main-nav .nav-cta:hover {
  background: var(--primary-dark);
  box-shadow: 0 2px 8px rgba(26, 115, 232, .3);
}

/* ========== Hero CTA Buttons ========== */
.hero-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.hero-btn {
  display: inline-block;
  padding: 16px 36px;
  border-radius: 28px;
  font-size: 1.05rem;
  font-weight: 700;
  transition: all var(--transition);
}

.hero-btn-primary {
  background: #fff;
  color: var(--primary);
}

.hero-btn-primary:hover {
  background: var(--primary-light);
  color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0,0,0,.2);
}

.hero-btn-secondary {
  background: rgba(255,255,255,.15);
  color: #fff;
  border: 2px solid rgba(255,255,255,.5);
}

.hero-btn-secondary:hover {
  background: rgba(255,255,255,.25);
  border-color: #fff;
  transform: translateY(-2px);
}

/* ========== About Table (auto style) ========== */
.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0 28px;
  font-size: .925rem;
}

.article-body table th,
.article-body table td {
  padding: 12px 16px;
  border: 1px solid var(--border);
  text-align: left;
}

.article-body table th {
  background: var(--primary);
  color: #fff;
  font-weight: 600;
}

.article-body table tr:nth-child(even) { background: var(--bg-alt); }
.article-body table tr:hover { background: var(--primary-light); }

/* ========== City Grid ========== */
.city-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
  margin-bottom: 40px;
}

.city-card {
  display: block;
  padding: 24px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all var(--transition);
  color: var(--text);
}

.city-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

.city-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.city-card p {
  font-size: .825rem;
  color: var(--text-secondary);
}

/* ========== Tag ========== */
.tag {
  display: inline-block;
  background: var(--primary-light);
  color: var(--primary);
  font-size: .78rem;
  padding: 3px 10px;
  border-radius: 20px;
  margin-bottom: 12px;
  font-weight: 600;
}

/* ========== Responsive ========== */
@media (max-width: 900px) {
  .content-layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .cat-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 768px) {
  .menu-toggle { display: block; min-width: 44px; min-height: 44px; padding: 10px; }
  .main-nav a { padding: 12px 16px; }
  .main-nav {
    display: none; position: absolute; top: var(--header-h);
    left: 0; right: 0; background: #fff; z-index: 999;
    flex-direction: column; padding: 12px 20px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
  }
  .main-nav.open { display: flex; }
  .main-nav .nav-cta { text-align: center; }
  .site-logo { white-space: normal; font-size: 1.1rem; }
  .site-logo .logo-slogan { display: none; }
  .hero h1 { font-size: 1.75rem; }
  .hero { padding: 50px 0 60px; }
  .hero-buttons { flex-direction: column; align-items: center; }
  .hero-btn { width: 100%; max-width: 300px; text-align: center; }
  .page-banner { padding: 32px 0; }
  .page-banner h1 { font-size: 1.5rem; }
  .page-banner p { font-size: .9rem; }
  .section-title { font-size: 1.4rem; }
  .section-subtitle { font-size: .925rem; margin-bottom: 28px; }
  .faq-question { padding: 14px 16px; font-size: .925rem; }
  .faq-answer { padding: 0 16px; }
  .faq-item.active .faq-answer { padding: 0 16px 16px; max-height: 70vh; }
  .cards-grid, .qa-list, .related-list, .card-grid, .solutions-grid { grid-template-columns: 1fr; }
  .cat-grid { grid-template-columns: repeat(3, 1fr); }
  .city-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr; }
  .article-table { font-size: .825rem; }
  .article-table th, .article-table td { padding: 8px 10px; }
  .article-body table th, .article-body table td { padding: 8px 10px; font-size: .825rem; }
  .breadcrumb { font-size: .8rem; }
  .article-body h1 { font-size: 1.45rem; }
  .article-body h2 { font-size: 1.2rem; }
}

@media (max-width: 480px) {
  .cat-grid { grid-template-columns: repeat(2, 1fr); }
  .city-grid { grid-template-columns: 1fr; }
}

@media (max-width: 375px) {
  .container { padding: 0 16px; }
  .hero h1 { font-size: 1.5rem; }
  .section-title { font-size: 1.25rem; }
  .cat-grid { grid-template-columns: 1fr; }
}