/* ============================================
   91 - 汽车改装视频社区 原创样式表
   品牌：91 | 域名：zza5jdt.cn
   配色：深邃夜蓝 + 赛道橙红 + 涡轮绿
   ============================================ */

/* === 基础重置与变量 === */
:root {
  --kkt-primary: #1A1F2E;
  --kkt-accent: #FF4D2A;
  --kkt-teal: #00D4AA;
  --kkt-bg: #0D1117;
  --kkt-card: #161B26;
  --kkt-card-hover: #1E2536;
  --kkt-text: #E8ECF1;
  --kkt-text-sub: #8B95A5;
  --kkt-border: #2A3142;
  --kkt-gradient-start: #FF4D2A;
  --kkt-gradient-end: #FF8C42;
  --kkt-shadow: rgba(0,0,0,0.35);
  --kkt-radius: 12px;
  --kkt-radius-sm: 8px;
  --kkt-transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --kkt-max-width: 1280px;
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background-color: var(--kkt-bg);
  color: var(--kkt-text);
  line-height: 1.7;
  overflow-x: hidden;
}

a {
  color: var(--kkt-teal);
  text-decoration: none;
  transition: color var(--kkt-transition);
}

a:hover {
  color: var(--kkt-accent);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

/* === 干扰标签隐藏 === */
.kkt-noise {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
  opacity: 0;
  pointer-events: none;
  z-index: -9999;
  font-size: 0;
  line-height: 0;
  visibility: hidden;
}

/* === 顶部导航 === */
.kkt-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(13, 17, 23, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--kkt-border);
  transition: background var(--kkt-transition);
}

.kkt-header-inner {
  max-width: var(--kkt-max-width);
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.kkt-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.kkt-logo img {
  height: 42px;
  width: auto;
}

.kkt-logo-text {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--kkt-text);
  letter-spacing: 1px;
}

.kkt-logo-text span {
  color: var(--kkt-accent);
}

.kkt-nav {
  display: flex;
  align-items: center;
  gap: 6px;
}

.kkt-nav a {
  color: var(--kkt-text-sub);
  padding: 8px 14px;
  border-radius: var(--kkt-radius-sm);
  font-size: 0.92rem;
  font-weight: 500;
  transition: all var(--kkt-transition);
  white-space: nowrap;
}

.kkt-nav a:hover,
.kkt-nav a.active {
  color: var(--kkt-text);
  background: rgba(255, 77, 42, 0.12);
}

.kkt-nav a.active {
  color: var(--kkt-accent);
}

/* 搜索框 */
.kkt-search-bar {
  max-width: var(--kkt-max-width);
  margin: 0 auto;
  padding: 12px 20px;
  background: var(--kkt-primary);
  border-bottom: 1px solid var(--kkt-border);
}

.kkt-search-wrap {
  display: flex;
  align-items: center;
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  border-radius: 40px;
  padding: 4px 6px 4px 20px;
  max-width: 640px;
  margin: 0 auto;
  transition: border-color var(--kkt-transition);
}

.kkt-search-wrap:focus-within {
  border-color: var(--kkt-accent);
}

.kkt-search-wrap input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--kkt-text);
  font-size: 0.9rem;
  padding: 8px 0;
}

.kkt-search-wrap input::placeholder {
  color: var(--kkt-text-sub);
}

.kkt-search-btn {
  background: linear-gradient(135deg, var(--kkt-gradient-start), var(--kkt-gradient-end));
  color: #fff;
  border: none;
  border-radius: 30px;
  padding: 8px 22px;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--kkt-transition), box-shadow var(--kkt-transition);
}

.kkt-search-btn:hover {
  transform: scale(1.04);
  box-shadow: 0 4px 16px rgba(255, 77, 42, 0.35);
}

/* 移动端菜单按钮 */
.kkt-menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--kkt-text);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 8px;
}

/* === Hero区域 === */
.kkt-hero {
  position: relative;
  margin-top: 68px;
  height: 520px;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.kkt-hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  filter: brightness(0.45);
  transform: scale(1.05);
  transition: transform 8s ease;
}

.kkt-hero:hover .kkt-hero-bg {
  transform: scale(1.1);
}

.kkt-hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(13,17,23,0.3) 0%, rgba(13,17,23,0.85) 100%);
}

.kkt-hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 0 20px;
  max-width: 800px;
}

.kkt-hero h1 {
  font-size: 2.8rem;
  font-weight: 800;
  margin-bottom: 16px;
  line-height: 1.2;
  text-shadow: 0 2px 20px rgba(0,0,0,0.5);
}

.kkt-hero h1 .kkt-brand {
  color: var(--kkt-accent);
}

.kkt-hero p {
  font-size: 1.15rem;
  color: var(--kkt-text-sub);
  margin-bottom: 28px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.kkt-hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
  margin-top: 30px;
}

.kkt-hero-stat {
  text-align: center;
}

.kkt-hero-stat .num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--kkt-accent);
  display: block;
}

.kkt-hero-stat .label {
  font-size: 0.85rem;
  color: var(--kkt-text-sub);
}

/* === 通用按钮 === */
.kkt-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 40px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--kkt-transition);
}

.kkt-btn-primary {
  background: linear-gradient(135deg, var(--kkt-gradient-start), var(--kkt-gradient-end));
  color: #fff;
  box-shadow: 0 4px 20px rgba(255, 77, 42, 0.3);
}

.kkt-btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(255, 77, 42, 0.45);
  color: #fff;
}

.kkt-btn-outline {
  background: transparent;
  color: var(--kkt-teal);
  border: 2px solid var(--kkt-teal);
}

.kkt-btn-outline:hover {
  background: var(--kkt-teal);
  color: var(--kkt-bg);
}

/* === 区块标题 === */
.kkt-section {
  padding: 70px 0;
}

.kkt-section-header {
  text-align: center;
  margin-bottom: 48px;
}

.kkt-section-header h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 12px;
  position: relative;
  display: inline-block;
}

.kkt-section-header h2::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 50px;
  height: 3px;
  background: linear-gradient(90deg, var(--kkt-accent), var(--kkt-teal));
  border-radius: 2px;
}

.kkt-section-header h2 .kkt-brand {
  color: var(--kkt-accent);
}

.kkt-section-header p {
  color: var(--kkt-text-sub);
  font-size: 1rem;
  margin-top: 16px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* === 视频卡片网格 === */
.kkt-video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

.kkt-video-card {
  background: var(--kkt-card);
  border-radius: var(--kkt-radius);
  overflow: hidden;
  border: 1px solid var(--kkt-border);
  transition: all var(--kkt-transition);
  cursor: pointer;
}

.kkt-video-card:hover {
  transform: translateY(-4px);
  border-color: var(--kkt-accent);
  box-shadow: 0 12px 40px var(--kkt-shadow);
}

.kkt-video-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
}

.kkt-video-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--kkt-transition);
}

.kkt-video-card:hover .kkt-video-thumb img {
  transform: scale(1.06);
}

.kkt-video-play {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.35);
  opacity: 0;
  transition: opacity var(--kkt-transition);
}

.kkt-video-card:hover .kkt-video-play {
  opacity: 1;
}

.kkt-play-icon {
  width: 60px;
  height: 60px;
  background: rgba(255, 77, 42, 0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--kkt-transition);
}

.kkt-play-icon::after {
  content: '';
  display: block;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent #fff;
  margin-left: 4px;
}

.kkt-video-card:hover .kkt-play-icon {
  transform: scale(1.1);
}

.kkt-video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.78rem;
  font-weight: 600;
}

.kkt-video-info {
  padding: 16px;
}

.kkt-video-info h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 8px;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.kkt-video-meta {
  display: flex;
  align-items: center;
  gap: 14px;
  color: var(--kkt-text-sub);
  font-size: 0.82rem;
}

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

.kkt-tag {
  display: inline-block;
  background: rgba(0, 212, 170, 0.12);
  color: var(--kkt-teal);
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 500;
  margin-top: 8px;
}

/* === 功能模块网格 === */
.kkt-feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.kkt-feature-card {
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  border-radius: var(--kkt-radius);
  padding: 28px;
  transition: all var(--kkt-transition);
  position: relative;
  overflow: hidden;
}

.kkt-feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--kkt-accent), var(--kkt-teal));
  transform: scaleX(0);
  transition: transform var(--kkt-transition);
}

.kkt-feature-card:hover::before {
  transform: scaleX(1);
}

.kkt-feature-card:hover {
  background: var(--kkt-card-hover);
  transform: translateY(-3px);
  box-shadow: 0 8px 30px var(--kkt-shadow);
}

.kkt-feature-icon {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 18px;
  background: rgba(255, 77, 42, 0.12);
  color: var(--kkt-accent);
}

.kkt-feature-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.kkt-feature-card p {
  color: var(--kkt-text-sub);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* === 专家展示 === */
.kkt-expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.kkt-expert-card {
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  border-radius: var(--kkt-radius);
  padding: 28px;
  text-align: center;
  transition: all var(--kkt-transition);
}

.kkt-expert-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px var(--kkt-shadow);
  border-color: var(--kkt-teal);
}

.kkt-expert-avatar {
  width: 90px;
  height: 90px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 16px;
  border: 3px solid var(--kkt-border);
  transition: border-color var(--kkt-transition);
}

.kkt-expert-card:hover .kkt-expert-avatar {
  border-color: var(--kkt-accent);
}

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

.kkt-expert-role {
  color: var(--kkt-accent);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 12px;
}

.kkt-expert-card p {
  color: var(--kkt-text-sub);
  font-size: 0.88rem;
  line-height: 1.5;
  margin-bottom: 16px;
}

.kkt-expert-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
}

.kkt-expert-actions a {
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 500;
  border: 1px solid var(--kkt-border);
  color: var(--kkt-text-sub);
  transition: all var(--kkt-transition);
}

.kkt-expert-actions a:hover {
  border-color: var(--kkt-accent);
  color: var(--kkt-accent);
  background: rgba(255, 77, 42, 0.08);
}

/* === 合作品牌墙 === */
.kkt-brand-wall {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 30px;
  align-items: center;
}

.kkt-brand-item {
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  border-radius: var(--kkt-radius-sm);
  padding: 18px 30px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--kkt-text-sub);
  transition: all var(--kkt-transition);
  letter-spacing: 1px;
}

.kkt-brand-item:hover {
  color: var(--kkt-text);
  border-color: var(--kkt-accent);
  transform: scale(1.05);
}

/* === FAQ === */
.kkt-faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.kkt-faq-item {
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  border-radius: var(--kkt-radius-sm);
  margin-bottom: 12px;
  overflow: hidden;
  transition: border-color var(--kkt-transition);
}

.kkt-faq-item:hover {
  border-color: var(--kkt-accent);
}

.kkt-faq-q {
  padding: 18px 24px;
  font-weight: 600;
  font-size: 0.98rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

.kkt-faq-q::after {
  content: '+';
  font-size: 1.3rem;
  color: var(--kkt-accent);
  transition: transform var(--kkt-transition);
  flex-shrink: 0;
  margin-left: 12px;
}

.kkt-faq-item.active .kkt-faq-q::after {
  transform: rotate(45deg);
}

.kkt-faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
}

.kkt-faq-item.active .kkt-faq-a {
  max-height: 300px;
  padding: 0 24px 18px;
}

.kkt-faq-a p {
  color: var(--kkt-text-sub);
  font-size: 0.9rem;
  line-height: 1.7;
}

/* === 用户评论 === */
.kkt-review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

.kkt-review-card {
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  border-radius: var(--kkt-radius);
  padding: 24px;
  transition: all var(--kkt-transition);
}

.kkt-review-card:hover {
  border-color: var(--kkt-teal);
  transform: translateY(-2px);
}

.kkt-review-stars {
  color: #FFB800;
  font-size: 0.9rem;
  margin-bottom: 12px;
  letter-spacing: 2px;
}

.kkt-review-card blockquote {
  color: var(--kkt-text);
  font-size: 0.92rem;
  line-height: 1.6;
  margin-bottom: 14px;
  font-style: italic;
}

.kkt-review-author {
  display: flex;
  align-items: center;
  gap: 10px;
}

.kkt-review-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--kkt-accent), var(--kkt-teal));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 0.85rem;
  font-weight: 700;
}

.kkt-review-name {
  font-size: 0.85rem;
  font-weight: 600;
}

.kkt-review-date {
  font-size: 0.78rem;
  color: var(--kkt-text-sub);
}

/* === 联系我们 === */
.kkt-contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 24px;
}

.kkt-contact-card {
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  border-radius: var(--kkt-radius);
  padding: 28px;
  text-align: center;
  transition: all var(--kkt-transition);
}

.kkt-contact-card:hover {
  border-color: var(--kkt-accent);
  transform: translateY(-2px);
}

.kkt-contact-card h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--kkt-accent);
}

.kkt-contact-card p {
  color: var(--kkt-text-sub);
  font-size: 0.88rem;
  line-height: 1.6;
}

.kkt-contact-card img {
  max-width: 120px;
  margin: 12px auto 0;
}

/* === 页脚 === */
.kkt-footer {
  background: var(--kkt-primary);
  border-top: 1px solid var(--kkt-border);
  padding: 50px 0 30px;
}

.kkt-footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.kkt-footer-brand p {
  color: var(--kkt-text-sub);
  font-size: 0.88rem;
  line-height: 1.6;
  margin-top: 14px;
}

.kkt-footer h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--kkt-text);
}

.kkt-footer-links {
  list-style: none;
}

.kkt-footer-links li {
  margin-bottom: 8px;
}

.kkt-footer-links a {
  color: var(--kkt-text-sub);
  font-size: 0.88rem;
  transition: color var(--kkt-transition);
}

.kkt-footer-links a:hover {
  color: var(--kkt-accent);
}

.kkt-footer-qr {
  display: flex;
  gap: 16px;
}

.kkt-footer-qr-item {
  text-align: center;
}

.kkt-footer-qr-item img {
  width: 100px;
  height: 100px;
  background: #fff;
  padding: 6px;
  border-radius: 8px;
  margin-bottom: 6px;
}

.kkt-footer-qr-item span {
  font-size: 0.78rem;
  color: var(--kkt-text-sub);
}

.kkt-footer-bottom {
  border-top: 1px solid var(--kkt-border);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.kkt-footer-bottom p {
  color: var(--kkt-text-sub);
  font-size: 0.82rem;
}

.kkt-social-links {
  display: flex;
  gap: 12px;
}

.kkt-social-links a {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--kkt-card);
  border: 1px solid var(--kkt-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--kkt-text-sub);
  font-size: 0.85rem;
  transition: all var(--kkt-transition);
}

.kkt-social-links a:hover {
  background: var(--kkt-accent);
  border-color: var(--kkt-accent);
  color: #fff;
}

/* === 面包屑 === */
.kkt-breadcrumb {
  padding: 14px 0;
  margin-top: 68px;
  background: var(--kkt-primary);
  border-bottom: 1px solid var(--kkt-border);
}

.kkt-breadcrumb-list {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
  font-size: 0.85rem;
}

.kkt-breadcrumb-list li {
  color: var(--kkt-text-sub);
}

.kkt-breadcrumb-list li a {
  color: var(--kkt-text-sub);
}

.kkt-breadcrumb-list li a:hover {
  color: var(--kkt-accent);
}

.kkt-breadcrumb-list li + li::before {
  content: '>';
  margin-right: 8px;
  color: var(--kkt-text-sub);
}

/* === How-To指南 === */
.kkt-howto-steps {
  max-width: 700px;
  margin: 0 auto;
  position: relative;
}

.kkt-howto-steps::before {
  content: '';
  position: absolute;
  left: 24px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--kkt-border);
}

.kkt-howto-step {
  display: flex;
  gap: 20px;
  margin-bottom: 28px;
  position: relative;
}

.kkt-step-num {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--kkt-accent), var(--kkt-gradient-end));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
  z-index: 1;
}

.kkt-step-content h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.kkt-step-content p {
  color: var(--kkt-text-sub);
  font-size: 0.9rem;
}

/* === 分享按钮 === */
.kkt-share-bar {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 20px;
}

.kkt-share-btn {
  padding: 8px 18px;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 500;
  border: 1px solid var(--kkt-border);
  color: var(--kkt-text-sub);
  background: var(--kkt-card);
  cursor: pointer;
  transition: all var(--kkt-transition);
}

.kkt-share-btn:hover {
  border-color: var(--kkt-accent);
  color: var(--kkt-accent);
}

/* === 内页内容区 === */
.kkt-page-hero {
  margin-top: 68px;
  padding: 60px 0;
  background: linear-gradient(135deg, var(--kkt-primary), var(--kkt-bg));
  text-align: center;
  border-bottom: 1px solid var(--kkt-border);
}

.kkt-page-hero h1 {
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.kkt-page-hero p {
  color: var(--kkt-text-sub);
  font-size: 1rem;
  max-width: 600px;
  margin: 0 auto;
}

/* === 响应式 === */
@media (max-width: 1024px) {
  .kkt-footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .kkt-menu-toggle {
    display: block;
  }

  .kkt-nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: rgba(13, 17, 23, 0.98);
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--kkt-border);
  }

  .kkt-nav.active {
    display: flex;
  }

  .kkt-nav a {
    padding: 12px 16px;
    width: 100%;
  }

  .kkt-hero {
    height: 400px;
  }

  .kkt-hero h1 {
    font-size: 1.8rem;
  }

  .kkt-hero-stats {
    gap: 20px;
  }

  .kkt-hero-stat .num {
    font-size: 1.4rem;
  }

  .kkt-section {
    padding: 45px 0;
  }

  .kkt-section-header h2 {
    font-size: 1.5rem;
  }

  .kkt-video-grid {
    grid-template-columns: 1fr;
  }

  .kkt-feature-grid {
    grid-template-columns: 1fr;
  }

  .kkt-expert-grid {
    grid-template-columns: 1fr;
  }

  .kkt-review-grid {
    grid-template-columns: 1fr;
  }

  .kkt-contact-grid {
    grid-template-columns: 1fr;
  }

  .kkt-footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .kkt-footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .kkt-page-hero h1 {
    font-size: 1.6rem;
  }
}

@media (max-width: 480px) {
  .kkt-hero {
    height: 340px;
  }

  .kkt-hero h1 {
    font-size: 1.5rem;
  }

  .kkt-hero-stats {
    flex-direction: column;
    gap: 12px;
  }
}

/* === 懒加载占位 === */
img[loading="lazy"] {
  background: var(--kkt-card);
  min-height: 100px;
}

/* === 滚动动画 === */
.kkt-fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.kkt-fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}