/* ========================================
   司盟企服 - 官网全局样式
   专业商务风（深色/蓝黑系）
   ======================================== */

/* CSS Reset & 基础 */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #1a56db;
  --primary-dark: #0f3a9e;
  --primary-light: #3b82f6;
  --accent: #f59e0b;
  --accent-dark: #d97706;
  --dark-900: #0f172a;
  --dark-800: #1e293b;
  --dark-700: #334155;
  --dark-600: #475569;
  --gray-500: #64748b;
  --gray-400: #94a3b8;
  --gray-300: #cbd5e1;
  --gray-100: #f1f5f9;
  --white: #ffffff;
  --success: #10b981;
  --danger: #ef4444;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,.1), 0 2px 4px -2px rgba(0,0,0,.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,.1), 0 4px 6px -4px rgba(0,0,0,.1);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,.1), 0 8px 10px -6px rgba(0,0,0,.1);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --transition: all .3s ease;
  --max-width: 1200px;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  color: var(--dark-800);
  line-height: 1.7;
  background-color: var(--white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

h1, h2, h3, h4, h5, h6 {
  line-height: 1.3;
  color: var(--dark-900);
  font-weight: 700;
}

h1 { font-size: 2.25rem; margin-bottom: 1rem; }
h2 { font-size: 1.75rem; margin-bottom: .75rem; }
h3 { font-size: 1.375rem; margin-bottom: .5rem; }
h4 { font-size: 1.125rem; margin-bottom: .5rem; }
p { margin-bottom: 1rem; color: var(--dark-600); }

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ========== Header / 导航栏 ========== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(15, 23, 42, .95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,.08);
  transition: var(--transition);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}
.logo {
  display: flex;
  align-items: center;
  gap: .5rem;
  font-size: 1.375rem;
  font-weight: 800;
  color: var(--white) !important;
  text-decoration: none !important;
}
.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 900;
  font-size: 1rem;
}
.nav { display: flex; align-items: center; gap: .25rem; }
.nav a {
  color: var(--gray-300);
  padding: .5rem 1rem;
  border-radius: var(--radius-sm);
  font-size: .9375rem;
  font-weight: 500;
  transition: var(--transition);
  position: relative;
}
.nav a:hover,
.nav a.active {
  color: var(--white);
  background: rgba(255,255,255,.08);
  text-decoration: none;
}
.nav a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}

/* CTA 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  padding: .75rem 1.75rem;
  border-radius: var(--radius-sm);
  font-size: .9375rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-decoration: none;
  line-height: 1.4;
}
.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: white;
  box-shadow: 0 4px 14px rgba(26,86,219,.35);
}
.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(26,86,219,.45);
  color: white;
}
.btn-accent {
  background: linear-gradient(135deg, var(--accent), var(--accent-dark));
  color: white;
  box-shadow: 0 4px 14px rgba(245,158,11,.35);
}
.btn-accent:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(245,158,11,.45);
  color: white;
}
.btn-outline {
  background: transparent;
  color: var(--white);
  border: 1.5px solid rgba(255,255,255,.3);
}
.btn-outline:hover {
  background: rgba(255,255,255,.08);
  border-color: rgba(255,255,255,.5);
  color: var(--white);
}
.btn-white {
  background: white;
  color: var(--primary-dark);
  box-shadow: var(--shadow-md);
}
.btn-white:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
  color: var(--primary-dark);
}
.btn-lg { padding: 1rem 2.25rem; font-size: 1.0625rem; }

/* 移动端汉堡菜单 */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: .5rem;
}
.menu-toggle span {
  width: 24px;
  height: 2px;
  background: var(--white);
  border-radius: 1px;
  transition: var(--transition);
}

/* ========== Hero 区域 ========== */
.hero {
  position: relative;
  min-height: 85vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: linear-gradient(135deg, var(--dark-900) 0%, var(--dark-800) 50%, #162056 100%);
  padding-top: 72px;
}
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -30%;
  width: 80%;
  height: 200%;
  background: radial-gradient(circle, rgba(59,130,246,.12) 0%, transparent 60%);
  pointer-events: none;
}
.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -20%;
  width: 60%;
  height: 160%;
  background: radial-gradient(circle, rgba(245,158,11,.07) 0%, transparent 55%);
  pointer-events: none;
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 720px;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  background: rgba(59,130,246,.12);
  color: var(--primary-light);
  padding: .4rem 1rem;
  border-radius: 999px;
  font-size: .8125rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  border: 1px solid rgba(59,130,246,.2);
}
.hero h1 {
  color: var(--white);
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.2;
  margin-bottom: 1.25rem;
}
.hero h1 span {
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-desc {
  color: var(--gray-400);
  font-size: 1.125rem;
  line-height: 1.8;
  margin-bottom: 2rem;
  max-width: 580px;
}
.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}
.hero-stats {
  display: flex;
  gap: 2.5rem;
  margin-top: 3.5rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255,255,255,.08);
}
.hero-stat-num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--white);
  line-height: 1;
}
.hero-stat-label {
  font-size: .8125rem;
  color: var(--gray-500);
  margin-top: .25rem;
}

/* ========== Section 通用 ========== */
.section {
  padding: 5rem 0;
}
.section-alt {
  background: var(--gray-100);
}
.section-header {
  text-align: center;
  max-width: 650px;
  margin: 0 auto 3rem;
}
.section-tag {
  display: inline-block;
  color: var(--primary);
  font-size: .8125rem;
  font-weight: 700;
  letter-spacing: .05em;
  text-transform: uppercase;
  margin-bottom: .5rem;
}
.section-header h2 {
  font-size: 2rem;
}
.section-header p {
  color: var(--gray-500);
  font-size: 1.0625rem;
  margin-bottom: 0;
}

/* ========== 服务卡片网格 ========== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.service-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 2rem;
  border: 1px solid var(--gray-300);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}
.service-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-light);
}
.service-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.25rem;
  background: rgba(26,86,219,.08);
  color: var(--primary);
}
.service-card h3 {
  font-size: 1.1875rem;
  margin-bottom: .5rem;
}
.service-card p {
  font-size: .9375rem;
  color: var(--gray-500);
  margin-bottom: 1rem;
}
.service-link {
  display: inline-flex;
  align-items: center;
  gap: .25rem;
  font-size: .9375rem;
  font-weight: 600;
  color: var(--primary);
}
.service-link::after {
  content: '→';
  transition: var(--transition);
}
.service-link:hover::after {
  transform: translateX(4px);
}

/* ========== 特色/优势区块 ========== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}
.feature-item {
  text-align: center;
  padding: 1.5rem 1rem;
}
.feature-icon {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: linear-gradient(135deg, rgba(26,86,219,.08), rgba(59,130,246,.08));
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1rem;
  font-size: 1.5rem;
  color: var(--primary);
}
.feature-item h4 {
  font-size: 1rem;
  margin-bottom: .25rem;
}
.feature-item p {
  font-size: .8125rem;
  color: var(--gray-500);
  margin-bottom: 0;
}

/* ========== 流程步骤 ========== */
.steps {
  display: flex;
  justify-content: space-between;
  position: relative;
  max-width: 900px;
  margin: 0 auto;
}
.steps::before {
  content: '';
  position: absolute;
  top: 32px;
  left: 60px;
  right: 60px;
  height: 2px;
  background: var(--gray-300);
  z-index: 0;
}
.step {
  flex: 1;
  text-align: center;
  position: relative;
  z-index: 1;
}
.step-num {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--white);
  border: 3px solid var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1rem;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--primary);
}
.step h4 {
  font-size: .9375rem;
  margin-bottom: .25rem;
}
.step p {
  font-size: .8125rem;
  color: var(--gray-500);
  margin-bottom: 0;
}

/* ========== FAQ 手风琴 ========== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}
.faq-item {
  background: var(--white);
  border: 1px solid var(--gray-300);
  border-radius: var(--radius-md);
  margin-bottom: .75rem;
  overflow: hidden;
  transition: var(--transition);
}
.faq-item:hover { border-color: var(--primary-light); }
.faq-q {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--dark-900);
  user-select: none;
  transition: var(--transition);
}
.faq-q:hover { color: var(--primary); }
.faq-q::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--gray-400);
  transition: var(--transition);
  flex-shrink: 0;
  margin-left: 1rem;
}
.faq-item.open .faq-q::after { 
  content: '−'; 
  color: var(--primary);
}
.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height .3s ease;
}
.faq-a-inner {
  padding: 0 1.5rem 1.25rem;
  color: var(--dark-600);
  line-height: 1.8;
  font-size: .9375rem;
}
.faq-item.open .faq-a {
  max-height: 500px;
}

/* ========== CTA 区块 ========== */
.cta-section {
  background: linear-gradient(135deg, var(--dark-900), #162056);
  padding: 4.5rem 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-section::before {
  content: '';
  position: absolute;
  top: -40%;
  left: 50%;
  transform: translateX(-50%);
  width: 80%;
  height: 180%;
  background: radial-gradient(circle, rgba(245,158,11,.1) 0%, transparent 60%);
}
.cta-section * { position: relative; z-index: 2; }
.cta-section h2 {
  color: var(--white);
  font-size: 2rem;
  margin-bottom: 1rem;
}
.cta-section p {
  color: var(--gray-400);
  font-size: 1.125rem;
  max-width: 550px;
  margin: 0 auto 2rem;
}
.cta-actions { display: flex; justify-content: center; gap: 1rem; flex-wrap: wrap; }

/* ========== 文章列表 ========== */
.article-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.article-card {
  background: var(--white);
  border-radius: var(--radius-md);
  border: 1px solid var(--gray-300);
  overflow: hidden;
  transition: var(--transition);
}
.article-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}
.article-cat {
  display: inline-block;
  background: rgba(26,86,219,.08);
  color: var(--primary);
  font-size: .75rem;
  font-weight: 700;
  padding: .25rem .65rem;
  border-radius: 999px;
  margin-bottom: .75rem;
}
.article-body { padding: 1.5rem; }
.article-body h3 {
  font-size: 1.0625rem;
  line-height: 1.5;
  margin-bottom: .5rem;
}
.article-body h3 a { color: var(--dark-900); }
.article-body h3 a:hover { color: var(--primary); }
.article-body p {
  font-size: .875rem;
  color: var(--gray-500);
  margin-bottom: .75rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.article-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: .75rem;
  color: var(--gray-400);
}

/* ========== 知识库分类标签 ========== */
.kb-categories {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  justify-content: center;
  max-width: 900px;
  margin: 0 auto 3rem;
}
.kb-category {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .65rem 1.35rem;
  background: var(--white);
  border: 1px solid var(--gray-300);
  border-radius: 999px;
  font-size: .9375rem;
  font-weight: 500;
  color: var(--dark-700);
  transition: var(--transition);
}
.kb-category:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: rgba(26,86,219,.04);
  text-decoration: none;
}
.kb-category .cat-count {
  font-size: .75rem;
  color: var(--gray-400);
  background: var(--gray-100);
  padding: .1rem .5rem;
  border-radius: 999px;
}

/* ========== 面包屑导航 ========== */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: .5rem;
  padding: 1.25rem 0;
  font-size: .8125rem;
  color: var(--gray-400);
}
.breadcrumb a { color: var(--gray-500); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb .sep { color: var(--gray-300); }
.breadcrumb .current { color: var(--dark-600); }

/* ========== 页面头部横幅 ========== */
.page-banner {
  background: linear-gradient(135deg, var(--dark-900), #162056);
  padding: 7rem 0 4rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-banner::before {
  content: '';
  position: absolute;
  top: -30%;
  right: -20%;
  width: 60%;
  height: 150%;
  background: radial-gradient(circle, rgba(59,130,246,.1) 0%, transparent 60%);
}
.page-banner > * { position: relative; z-index: 2; }
.page-banner h1 { color: var(--white); font-size: 2.25rem; }
.page-banner p { color: var(--gray-400); font-size: 1.125rem; max-width: 600px; margin: 0 auto; }

/* ========== 文章页面样式 ========== */
.article-page {
  padding: 3.5rem 0 5rem;
}
.article-main {
  max-width: 780px;
  margin: 0 auto;
}
.article-main h1 {
  font-size: 2rem;
  line-height: 1.35;
  margin-bottom: 1rem;
}
.article-info {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding-bottom: 1.5rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--gray-300);
  font-size: .8125rem;
  color: var(--gray-500);
}
.article-body-content {
  font-size: 1.0625rem;
  line-height: 2;
  color: var(--dark-700);
}
.article-body-content h2 {
  font-size: 1.375rem;
  margin: 2rem 0 1rem;
  padding-left: 1rem;
  border-left: 3px solid var(--primary);
}
.article-body-content p {
  margin-bottom: 1.25rem;
  color: var(--dark-600);
}
.article-body-content ul,
.article-body-content ol {
  list-style: disc;
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
}
.article-body-content li { margin-bottom: .5rem; color: var(--dark-600); }

/* 相关文章推荐 */
.related-articles {
  margin-top: 3.5rem;
  padding-top: 2.5rem;
  border-top: 2px solid var(--gray-100);
}
.related-articles h3 { margin-bottom: 1.25rem; font-size: 1.25rem; }
.related-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
.related-item {
  display: block;
  padding: 1rem 1.25rem;
  background: var(--gray-100);
  border-radius: var(--radius-sm);
  color: var(--dark-700);
  font-size: .9375rem;
  font-weight: 500;
  transition: var(--transition);
}
.related-item:hover {
  background: rgba(26,86,219,.06);
  color: var(--primary);
  text-decoration: none;
}

/* ========== 联系信息卡片 ========== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}
.contact-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  border: 1px solid var(--gray-300);
}
.contact-card h3 {
  display: flex;
  align-items: center;
  gap: .5rem;
  font-size: 1.1875rem;
  margin-bottom: 1.5rem;
}
.contact-item {
  display: flex;
  align-items: flex-start;
  gap: .75rem;
  margin-bottom: 1rem;
}
.contact-item-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: rgba(26,86,219,.08);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--primary);
  font-size: .875rem;
}
.contact-item-label {
  font-size: .8125rem;
  color: var(--gray-500);
  margin-bottom: .1rem;
}
.contact-item-value {
  font-weight: 600;
  color: var(--dark-800);
  font-size: .9375rem;
}

/* ========== 关于我们 ========== */
.about-intro {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 4rem;
  align-items: center;
}
.about-highlights {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  margin-top: 2.5rem;
}
.about-highlight {
  background: var(--gray-100);
  border-radius: var(--radius-md);
  padding: 1.5rem;
}
.about-highlight-num {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
}
.about-highlight-label {
  font-size: .8125rem;
  color: var(--gray-500);
  margin-top: .25rem;
}

/* ========== Footer ========== */
.footer {
  background: var(--dark-900);
  color: var(--gray-400);
  padding: 4rem 0 2rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 3rem;
}
.footer-brand .logo { margin-bottom: 1rem; }
.footer-brand p {
  color: var(--gray-500);
  font-size: .875rem;
  line-height: 1.8;
  margin-bottom: 1rem;
}
.footer-col h4 {
  color: var(--white);
  font-size: .9375rem;
  margin-bottom: 1rem;
}
.footer-col a {
  display: block;
  color: var(--gray-500);
  padding: .3rem 0;
  font-size: .875rem;
}
.footer-col a:hover { color: var(--white); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08);
  padding-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: .8125rem;
}

/* ========== 服务详情页专用 ========== */
.service-detail-hero {
  padding: 7rem 0 4rem;
  background: linear-gradient(135deg, var(--dark-900), #162056);
  position: relative;
  overflow: hidden;
}
.service-detail-hero::before {
  content: '';
  position: absolute;
  top: -30%;
  right: -20%;
  width: 60%;
  height: 150%;
  background: radial-gradient(circle, rgba(59,130,246,.1) 0%, transparent 60%);
}
.service-detail-hero > * { position: relative; z-index: 2; }
.service-detail-hero h1 { color: var(--white); font-size: 2.25rem; margin-bottom: 1rem; }
.service-detail-hero p { color: var(--gray-400); font-size: 1.125rem; max-width: 650px; }

.service-section {
  padding: 3rem 0;
}
.service-section h2 { font-size: 1.5rem; margin-bottom: 1.5rem; }
.service-section-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
.service-point {
  background: var(--white);
  border: 1px solid var(--gray-300);
  border-radius: var(--radius-md);
  padding: 1.5rem;
}
.service-point-icon {
  font-size: 1.5rem;
  margin-bottom: .75rem;
}
.service-point h4 { margin-bottom: .5rem; }
.service-point p { font-size: .875rem; margin-bottom: 0; }

.risk-warning {
  background: rgba(239,68,68,.04);
  border: 1px solid rgba(239,68,68,.15);
  border-left: 3px solid var(--danger);
  border-radius: var(--radius-sm);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}
.risk-warning h4 { color: var(--danger); margin-bottom: .5rem; }
.risk-warning p { color: var(--danger); opacity: .85; margin-bottom: 0; font-size: .9375rem; }

.consult-box {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  text-align: center;
  color: var(--white);
  margin-top: 3rem;
}
.consult-box h3 { color: var(--white); margin-bottom: .75rem; }
.consult-box p { color: rgba(255,255,255,.85); margin-bottom: 1.5rem; }

/* ========== 响应式设计 ========== */
@media (max-width: 1024px) {
  .services-grid { grid-template-columns: repeat(2, 1fr); }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .about-intro { grid-template-columns: 1fr; gap: 2.5rem; }
  .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  html { font-size: 15px; }
  .nav {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--dark-900);
    flex-direction: column;
    padding: 1.5rem;
    gap: .25rem;
    transform: translateX(100%);
    transition: transform .3s ease;
  }
  .nav.open { transform: translateX(0); }
  .nav a {
    width: 100%;
    padding: .875rem 1rem;
    font-size: 1.0625rem;
  }
  .menu-toggle { display: flex; }
  
  .hero { min-height: auto; padding: 8rem 0 4rem; }
  .hero-stats { gap: 1.5rem; flex-wrap: wrap; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { justify-content: center; }
  
  .section { padding: 3.5rem 0; }
  .services-grid { grid-template-columns: 1fr; }
  .article-list { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr 1fr; }
  .steps { flex-direction: column; gap: 1.5rem; }
  .steps::before { display: none; }
  .cta-actions { flex-direction: column; align-items: center; }
  .about-highlights { grid-template-columns: 1fr 1fr; }
  .service-section-grid { grid-template-columns: 1fr 1fr; }
  .related-list { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 2rem; }
  .footer-bottom { flex-direction: column; gap: .5rem; text-align: center; }
  .page-banner { padding: 6rem 0 3rem; }
  .page-banner h1 { font-size: 1.75rem; }
  .kb-categories { justify-content: flex-start; }
}

@media (max-width: 480px) {
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.375rem; }
  .hero h1 { font-size: 1.75rem; }
  .features-grid { grid-template-columns: 1fr; }
  .about-highlights { grid-template-columns: 1fr; }
  .service-section-grid { grid-template-columns: 1fr; }
  .hero-stats { flex-direction: column; gap: 1rem; }
}

/* ========== 动画 ========== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
.fade-in-up {
  animation: fadeInUp .6s ease forwards;
}