/* ============================================================
   困困兔 - 汽车改装与视频社区 | hbaaiae.cn
   原创CSS样式 v1.0
   ============================================================ */

/* ---- CSS变量 / 品牌色系 ---- */
:root {
  --brand-primary: #FF6B00;
  --brand-dark: #0A0E1A;
  --brand-navy: #0D1B3E;
  --brand-accent: #1A2A5E;
  --brand-light: #F5F7FA;
  --brand-white: #FFFFFF;
  --brand-gray: #8A9BB5;
  --brand-border: #1E2D50;
  --brand-card: #111827;
  --font-main: 'PingFang SC','Microsoft YaHei','Hiragino Sans GB',sans-serif;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-card: 0 4px 24px rgba(0,0,0,0.35);
  --shadow-hover: 0 8px 40px rgba(255,107,0,0.25);
  --transition: all 0.3s cubic-bezier(0.4,0,0.2,1);
}

/* ---- 重置与基础 ---- */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px}
body{
  font-family:var(--font-main);
  background:var(--brand-dark);
  color:var(--brand-white);
  line-height:1.7;
  overflow-x:hidden;
}
a{color:var(--brand-primary);text-decoration:none;transition:var(--transition)}
a:hover{color:#FF8C33}
img{max-width:100%;height:auto;display:block}
ul,ol{list-style:none}
button{cursor:pointer;border:none;outline:none;background:none;font-family:var(--font-main)}

/* ---- 干扰标签隐藏 ---- */
.kktu-noise{display:none!important;visibility:hidden!important;position:absolute!important;width:0!important;height:0!important;overflow:hidden!important;opacity:0!important;pointer-events:none!important}

/* ---- 通用容器 ---- */
.container{max-width:1280px;margin:0 auto;padding:0 20px}
.section-gap{padding:80px 0}
.section-gap-sm{padding:50px 0}

/* ---- 通用标题 ---- */
.section-title{
  font-size:2rem;
  font-weight:700;
  color:var(--brand-white);
  margin-bottom:12px;
  position:relative;
}
.section-title span{color:var(--brand-primary)}
.section-subtitle{
  color:var(--brand-gray);
  font-size:1rem;
  margin-bottom:48px;
  max-width:600px;
}
.title-line{
  display:flex;
  align-items:center;
  gap:16px;
  margin-bottom:48px;
}
.title-line::after{
  content:'';
  flex:1;
  height:1px;
  background:linear-gradient(to right,var(--brand-border),transparent);
}

/* ---- 按钮 ---- */
.btn{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:12px 28px;
  border-radius:var(--radius-sm);
  font-size:0.95rem;
  font-weight:600;
  transition:var(--transition);
  letter-spacing:0.5px;
}
.btn-primary{
  background:var(--brand-primary);
  color:var(--brand-white);
  box-shadow:0 4px 16px rgba(255,107,0,0.4);
}
.btn-primary:hover{
  background:#E55A00;
  color:var(--brand-white);
  transform:translateY(-2px);
  box-shadow:0 8px 24px rgba(255,107,0,0.5);
}
.btn-outline{
  border:2px solid var(--brand-primary);
  color:var(--brand-primary);
  background:transparent;
}
.btn-outline:hover{
  background:var(--brand-primary);
  color:var(--brand-white);
  transform:translateY(-2px);
}
.btn-ghost{
  border:1px solid var(--brand-border);
  color:var(--brand-gray);
  background:transparent;
  font-size:0.85rem;
  padding:8px 18px;
}
.btn-ghost:hover{border-color:var(--brand-primary);color:var(--brand-primary)}

/* ---- 顶部公告条 ---- */
.top-bar{
  background:var(--brand-primary);
  color:var(--brand-white);
  text-align:center;
  padding:8px 20px;
  font-size:0.85rem;
  font-weight:500;
}
.top-bar a{color:var(--brand-white);text-decoration:underline}

/* ---- 导航栏 ---- */
.site-header{
  position:sticky;
  top:0;
  z-index:1000;
  background:rgba(10,14,26,0.95);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--brand-border);
  transition:var(--transition);
}
.header-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  height:70px;
  gap:24px;
}
.site-logo{
  display:flex;
  align-items:center;
  gap:12px;
  flex-shrink:0;
}
.site-logo img{
  width:44px;
  height:44px;
  border-radius:50%;
  object-fit:cover;
}
.logo-text{
  font-size:1.3rem;
  font-weight:800;
  color:var(--brand-white);
  letter-spacing:1px;
}
.logo-text span{color:var(--brand-primary)}

/* ---- 导航菜单 ---- */
.nav-menu{
  display:flex;
  align-items:center;
  gap:4px;
}
.nav-menu a{
  color:var(--brand-gray);
  font-size:0.9rem;
  font-weight:500;
  padding:8px 14px;
  border-radius:var(--radius-sm);
  transition:var(--transition);
  white-space:nowrap;
}
.nav-menu a:hover,.nav-menu a.active{
  color:var(--brand-white);
  background:var(--brand-accent);
}
.nav-menu a.nav-hot{color:var(--brand-primary)}

/* ---- 搜索框 ---- */
.header-search{
  display:flex;
  align-items:center;
  background:var(--brand-accent);
  border:1px solid var(--brand-border);
  border-radius:24px;
  padding:6px 16px;
  gap:8px;
  min-width:220px;
  transition:var(--transition);
}
.header-search:focus-within{
  border-color:var(--brand-primary);
  box-shadow:0 0 0 3px rgba(255,107,0,0.15);
}
.header-search input{
  background:none;
  border:none;
  outline:none;
  color:var(--brand-white);
  font-size:0.875rem;
  width:100%;
  font-family:var(--font-main);
}
.header-search input::placeholder{color:var(--brand-gray)}
.search-btn{
  color:var(--brand-gray);
  font-size:1rem;
  padding:0;
  transition:var(--transition);
}
.search-btn:hover{color:var(--brand-primary)}

/* ---- 汉堡菜单 ---- */
.hamburger{
  display:none;
  flex-direction:column;
  gap:5px;
  cursor:pointer;
  padding:8px;
}
.hamburger span{
  display:block;
  width:24px;
  height:2px;
  background:var(--brand-white);
  border-radius:2px;
  transition:var(--transition);
}

/* ---- 搜索建议弹窗 ---- */
.search-dropdown{
  display:none;
  position:absolute;
  top:calc(100% + 8px);
  left:0;
  right:0;
  background:var(--brand-navy);
  border:1px solid var(--brand-border);
  border-radius:var(--radius-md);
  padding:12px;
  z-index:200;
  box-shadow:var(--shadow-card);
}
.search-dropdown.show{display:block}
.search-dropdown p{
  font-size:0.8rem;
  color:var(--brand-gray);
  margin-bottom:8px;
}
.search-tags{display:flex;flex-wrap:wrap;gap:6px}
.search-tags span{
  background:var(--brand-accent);
  color:var(--brand-gray);
  padding:4px 12px;
  border-radius:20px;
  font-size:0.8rem;
  cursor:pointer;
  transition:var(--transition);
}
.search-tags span:hover{background:var(--brand-primary);color:#fff}

/* ---- 面包屑 ---- */
.breadcrumb{
  display:flex;
  align-items:center;
  gap:8px;
  font-size:0.85rem;
  color:var(--brand-gray);
  padding:16px 0;
}
.breadcrumb a{color:var(--brand-gray)}
.breadcrumb a:hover{color:var(--brand-primary)}
.breadcrumb .sep{color:var(--brand-border)}
.breadcrumb .current{color:var(--brand-white)}

/* ---- Hero区域 ---- */
.hero-section{
  position:relative;
  min-height:90vh;
  display:flex;
  align-items:center;
  overflow:hidden;
}
.hero-bg{
  position:absolute;
  inset:0;
  background:linear-gradient(135deg,#0A0E1A 0%,#0D1B3E 50%,#1A0A00 100%);
}
.hero-bg img{
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  object-fit:cover;
  opacity:0.35;
}
.hero-overlay{
  position:absolute;
  inset:0;
  background:linear-gradient(to right,rgba(10,14,26,0.9) 40%,transparent 100%);
}
.hero-content{
  position:relative;
  z-index:2;
  max-width:700px;
}
.hero-badge{
  display:inline-flex;
  align-items:center;
  gap:8px;
  background:rgba(255,107,0,0.15);
  border:1px solid rgba(255,107,0,0.4);
  color:var(--brand-primary);
  padding:6px 16px;
  border-radius:20px;
  font-size:0.85rem;
  font-weight:600;
  margin-bottom:24px;
}
.hero-badge::before{
  content:'';
  width:8px;
  height:8px;
  background:var(--brand-primary);
  border-radius:50%;
  animation:pulse 2s infinite;
}
@keyframes pulse{
  0%,100%{opacity:1;transform:scale(1)}
  50%{opacity:0.5;transform:scale(1.3)}
}
.hero-title{
  font-size:3.5rem;
  font-weight:900;
  line-height:1.15;
  margin-bottom:20px;
  letter-spacing:-1px;
}
.hero-title .brand{color:var(--brand-primary)}
.hero-desc{
  font-size:1.1rem;
  color:rgba(255,255,255,0.75);
  margin-bottom:36px;
  line-height:1.8;
}
.hero-actions{display:flex;gap:16px;flex-wrap:wrap;margin-bottom:48px}
.hero-stats{
  display:flex;
  gap:40px;
  flex-wrap:wrap;
}
.stat-item .num{
  font-size:2rem;
  font-weight:800;
  color:var(--brand-primary);
  line-height:1;
}
.stat-item .label{
  font-size:0.8rem;
  color:var(--brand-gray);
  margin-top:4px;
}

/* ---- 视频卡片 ---- */
.video-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(300px,1fr));
  gap:24px;
}
.video-card{
  background:var(--brand-card);
  border-radius:var(--radius-md);
  overflow:hidden;
  border:1px solid var(--brand-border);
  transition:var(--transition);
  cursor:pointer;
}
.video-card:hover{
  transform:translateY(-6px);
  border-color:var(--brand-primary);
  box-shadow:var(--shadow-hover);
}
.video-thumb{
  position:relative;
  padding-top:56.25%;
  overflow:hidden;
  background:#000;
}
.video-thumb img{
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  object-fit:cover;
  transition:transform 0.5s ease;
}
.video-card:hover .video-thumb img{transform:scale(1.08)}
.play-btn{
  position:absolute;
  inset:0;
  display:flex;
  align-items:center;
  justify-content:center;
  background:rgba(0,0,0,0.3);
  opacity:0;
  transition:var(--transition);
}
.video-card:hover .play-btn{opacity:1}
.play-icon{
  width:64px;
  height:64px;
  background:rgba(255,107,0,0.9);
  border-radius:50%;
  display:flex;
  align-items:center;
  justify-content:center;
  transform:scale(0.8);
  transition:var(--transition);
  box-shadow:0 0 30px rgba(255,107,0,0.6);
}
.video-card:hover .play-icon{transform:scale(1)}
.play-icon::after{
  content:'';
  border-left:22px solid #fff;
  border-top:13px solid transparent;
  border-bottom:13px solid transparent;
  margin-left:4px;
}
.video-duration{
  position:absolute;
  bottom:10px;
  right:10px;
  background:rgba(0,0,0,0.8);
  color:#fff;
  font-size:0.75rem;
  padding:2px 8px;
  border-radius:4px;
}
.video-tag{
  position:absolute;
  top:10px;
  left:10px;
  background:var(--brand-primary);
  color:#fff;
  font-size:0.7rem;
  padding:2px 10px;
  border-radius:4px;
  font-weight:600;
}
.video-info{padding:16px}
.video-title{
  font-size:0.95rem;
  font-weight:600;
  color:var(--brand-white);
  margin-bottom:8px;
  line-height:1.5;
  display:-webkit-box;
  -webkit-line-clamp:2;
  -webkit-box-orient:vertical;
  overflow:hidden;
}
.video-meta{
  display:flex;
  align-items:center;
  justify-content:space-between;
  font-size:0.8rem;
  color:var(--brand-gray);
}
.video-stats{display:flex;gap:12px;align-items:center}
.video-stats span{display:flex;align-items:center;gap:4px}

/* ---- 特色卡片 ---- */
.feature-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(260px,1fr));
  gap:24px;
}
.feature-card{
  background:var(--brand-card);
  border:1px solid var(--brand-border);
  border-radius:var(--radius-md);
  padding:32px 24px;
  transition:var(--transition);
  position:relative;
  overflow:hidden;
}
.feature-card::before{
  content:'';
  position:absolute;
  top:0;left:0;right:0;
  height:3px;
  background:linear-gradient(to right,var(--brand-primary),transparent);
  transform:scaleX(0);
  transform-origin:left;
  transition:var(--transition);
}
.feature-card:hover::before{transform:scaleX(1)}
.feature-card:hover{
  border-color:rgba(255,107,0,0.3);
  transform:translateY(-4px);
  box-shadow:var(--shadow-hover);
}
.feature-icon{
  width:56px;
  height:56px;
  background:rgba(255,107,0,0.1);
  border-radius:var(--radius-sm);
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:1.6rem;
  margin-bottom:20px;
  border:1px solid rgba(255,107,0,0.2);
}
.feature-title{
  font-size:1.05rem;
  font-weight:700;
  color:var(--brand-white);
  margin-bottom:10px;
}
.feature-desc{
  font-size:0.875rem;
  color:var(--brand-gray);
  line-height:1.7;
}

/* ---- 专家卡片 ---- */
.expert-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(280px,1fr));
  gap:28px;
}
.expert-card{
  background:var(--brand-card);
  border:1px solid var(--brand-border);
  border-radius:var(--radius-lg);
  overflow:hidden;
  transition:var(--transition);
}
.expert-card:hover{
  border-color:var(--brand-primary);
  transform:translateY(-6px);
  box-shadow:var(--shadow-hover);
}
.expert-photo{
  height:260px;
  overflow:hidden;
  position:relative;
}
.expert-photo img{
  width:100%;
  height:100%;
  object-fit:cover;
  object-position:top;
  transition:transform 0.5s ease;
}
.expert-card:hover .expert-photo img{transform:scale(1.06)}
.expert-badge{
  position:absolute;
  bottom:16px;
  left:16px;
  background:var(--brand-primary);
  color:#fff;
  font-size:0.75rem;
  padding:4px 12px;
  border-radius:20px;
  font-weight:600;
}
.expert-info{padding:20px}
.expert-name{
  font-size:1.1rem;
  font-weight:700;
  color:var(--brand-white);
  margin-bottom:4px;
}
.expert-role{
  font-size:0.85rem;
  color:var(--brand-primary);
  margin-bottom:12px;
}
.expert-desc{
  font-size:0.85rem;
  color:var(--brand-gray);
  line-height:1.6;
  margin-bottom:16px;
}
.expert-awards{
  display:flex;
  flex-wrap:wrap;
  gap:6px;
  margin-bottom:16px;
}
.award-tag{
  background:rgba(255,107,0,0.1);
  border:1px solid rgba(255,107,0,0.2);
  color:var(--brand-primary);
  font-size:0.75rem;
  padding:3px 10px;
  border-radius:20px;
}
.expert-actions{display:flex;gap:10px}

/* ---- 评价区 ---- */
.review-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(300px,1fr));
  gap:24px;
}
.review-card{
  background:var(--brand-card);
  border:1px solid var(--brand-border);
  border-radius:var(--radius-md);
  padding:24px;
  transition:var(--transition);
}
.review-card:hover{border-color:rgba(255,107,0,0.3)}
.review-stars{
  color:var(--brand-primary);
  font-size:1rem;
  margin-bottom:12px;
  letter-spacing:2px;
}
.review-text{
  font-size:0.9rem;
  color:rgba(255,255,255,0.85);
  line-height:1.8;
  margin-bottom:16px;
  font-style:italic;
}
.review-author{
  display:flex;
  align-items:center;
  gap:12px;
}
.author-avatar{
  width:40px;
  height:40px;
  border-radius:50%;
  background:linear-gradient(135deg,var(--brand-primary),#FF8C33);
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:1rem;
  font-weight:700;
  color:#fff;
  flex-shrink:0;
}
.author-name{
  font-size:0.9rem;
  font-weight:600;
  color:var(--brand-white);
}
.author-meta{
  font-size:0.78rem;
  color:var(--brand-gray);
}

/* ---- FAQ ---- */
.faq-list{max-width:860px;margin:0 auto}
.faq-item{
  border:1px solid var(--brand-border);
  border-radius:var(--radius-md);
  margin-bottom:12px;
  overflow:hidden;
  transition:var(--transition);
}
.faq-item.open{border-color:rgba(255,107,0,0.4)}
.faq-question{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:20px 24px;
  cursor:pointer;
  background:var(--brand-card);
  transition:var(--transition);
  font-size:0.95rem;
  font-weight:600;
  color:var(--brand-white);
  gap:16px;
}
.faq-question:hover{background:var(--brand-accent)}
.faq-item.open .faq-question{background:rgba(255,107,0,0.08);color:var(--brand-primary)}
.faq-arrow{
  font-size:1.2rem;
  transition:transform 0.3s;
  flex-shrink:0;
  color:var(--brand-primary);
}
.faq-item.open .faq-arrow{transform:rotate(45deg)}
.faq-answer{
  max-height:0;
  overflow:hidden;
  transition:max-height 0.4s ease,padding 0.3s;
  background:var(--brand-card);
  padding:0 24px;
  font-size:0.9rem;
  color:var(--brand-gray);
  line-height:1.8;
}
.faq-item.open .faq-answer{
  max-height:400px;
  padding:0 24px 20px;
}

/* ---- 合作品牌Logo墙 ---- */
.partner-logos{
  display:flex;
  flex-wrap:wrap;
  gap:20px;
  justify-content:center;
  align-items:center;
}
.partner-logo{
  background:var(--brand-card);
  border:1px solid var(--brand-border);
  border-radius:var(--radius-sm);
  padding:16px 28px;
  font-size:0.9rem;
  font-weight:700;
  color:var(--brand-gray);
  transition:var(--transition);
  letter-spacing:1px;
}
.partner-logo:hover{
  border-color:var(--brand-primary);
  color:var(--brand-primary);
  transform:translateY(-2px);
}

/* ---- AI赋能区 ---- */
.ai-section{
  background:linear-gradient(135deg,var(--brand-navy),var(--brand-dark));
  border-top:1px solid var(--brand-border);
  border-bottom:1px solid var(--brand-border);
}
.ai-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:60px;
  align-items:center;
}
.ai-img-wrap{
  border-radius:var(--radius-lg);
  overflow:hidden;
  border:1px solid var(--brand-border);
  box-shadow:var(--shadow-card);
}
.ai-features{display:flex;flex-direction:column;gap:20px}
.ai-feature-item{
  display:flex;
  gap:16px;
  align-items:flex-start;
}
.ai-icon{
  width:48px;
  height:48px;
  background:rgba(255,107,0,0.1);
  border-radius:var(--radius-sm);
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:1.4rem;
  flex-shrink:0;
  border:1px solid rgba(255,107,0,0.2);
}
.ai-feature-item h4{
  font-size:1rem;
  font-weight:700;
  color:var(--brand-white);
  margin-bottom:4px;
}
.ai-feature-item p{
  font-size:0.875rem;
  color:var(--brand-gray);
  line-height:1.6;
}

/* ---- 联系区 ---- */
.contact-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:40px;
}
.contact-card{
  background:var(--brand-card);
  border:1px solid var(--brand-border);
  border-radius:var(--radius-lg);
  padding:36px;
}
.contact-card h3{
  font-size:1.2rem;
  font-weight:700;
  color:var(--brand-white);
  margin-bottom:20px;
  padding-bottom:16px;
  border-bottom:1px solid var(--brand-border);
}
.contact-item{
  display:flex;
  gap:12px;
  align-items:flex-start;
  margin-bottom:16px;
}
.contact-icon{
  width:36px;
  height:36px;
  background:rgba(255,107,0,0.1);
  border-radius:var(--radius-sm);
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:1rem;
  flex-shrink:0;
}
.contact-label{
  font-size:0.8rem;
  color:var(--brand-gray);
  margin-bottom:2px;
}
.contact-value{
  font-size:0.9rem;
  color:var(--brand-white);
  font-weight:500;
}
.qr-row{
  display:flex;
  gap:24px;
  margin-top:24px;
}
.qr-item{text-align:center}
.qr-item img{
  width:120px;
  height:120px;
  border-radius:var(--radius-sm);
  border:2px solid var(--brand-border);
  margin:0 auto 8px;
}
.qr-item p{font-size:0.78rem;color:var(--brand-gray)}

/* ---- 社区加入指南 ---- */
.how-to-grid{
  display:grid;
  grid-template-columns:repeat(4,1fr);
  gap:24px;
}
.step-card{
  text-align:center;
  padding:28px 20px;
  background:var(--brand-card);
  border:1px solid var(--brand-border);
  border-radius:var(--radius-md);
  position:relative;
  transition:var(--transition);
}
.step-card:hover{border-color:rgba(255,107,0,0.4);transform:translateY(-4px)}
.step-num{
  width:48px;
  height:48px;
  background:var(--brand-primary);
  border-radius:50%;
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:1.2rem;
  font-weight:800;
  color:#fff;
  margin:0 auto 16px;
}
.step-title{
  font-size:0.95rem;
  font-weight:700;
  color:var(--brand-white);
  margin-bottom:8px;
}
.step-desc{
  font-size:0.82rem;
  color:var(--brand-gray);
  line-height:1.6;
}

/* ---- 分享按钮 ---- */
.share-bar{
  display:flex;
  align-items:center;
  gap:12px;
  flex-wrap:wrap;
}
.share-label{
  font-size:0.85rem;
  color:var(--brand-gray);
}
.share-btn{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:8px 16px;
  border-radius:20px;
  font-size:0.8rem;
  font-weight:600;
  transition:var(--transition);
  border:1px solid var(--brand-border);
  color:var(--brand-gray);
}
.share-btn:hover{transform:translateY(-2px)}
.share-wechat:hover{border-color:#07C160;color:#07C160}
.share-weibo:hover{border-color:#E6162D;color:#E6162D}
.share-douyin:hover{border-color:#FE2C55;color:#FE2C55}
.share-bilibili:hover{border-color:#00A1D6;color:#00A1D6}

/* ---- 页脚 ---- */
.site-footer{
  background:var(--brand-navy);
  border-top:1px solid var(--brand-border);
  padding:60px 0 0;
}
.footer-grid{
  display:grid;
  grid-template-columns:2fr 1fr 1fr 1fr;
  gap:40px;
  margin-bottom:40px;
}
.footer-brand .logo-text{font-size:1.4rem;margin-bottom:12px;display:block}
.footer-desc{
  font-size:0.875rem;
  color:var(--brand-gray);
  line-height:1.8;
  margin-bottom:20px;
}
.footer-col h4{
  font-size:0.95rem;
  font-weight:700;
  color:var(--brand-white);
  margin-bottom:16px;
  padding-bottom:10px;
  border-bottom:1px solid var(--brand-border);
}
.footer-col ul li{margin-bottom:8px}
.footer-col ul li a{
  font-size:0.85rem;
  color:var(--brand-gray);
  transition:var(--transition);
}
.footer-col ul li a:hover{color:var(--brand-primary);padding-left:4px}
.footer-bottom{
  border-top:1px solid var(--brand-border);
  padding:20px 0;
  display:flex;
  align-items:center;
  justify-content:space-between;
  flex-wrap:wrap;
  gap:12px;
}
.footer-copy{
  font-size:0.82rem;
  color:var(--brand-gray);
}
.footer-copy a{color:var(--brand-gray)}
.footer-copy a:hover{color:var(--brand-primary)}
.footer-links{
  display:flex;
  gap:20px;
}
.footer-links a{
  font-size:0.82rem;
  color:var(--brand-gray);
}
.footer-links a:hover{color:var(--brand-primary)}
.update-time{
  font-size:0.78rem;
  color:var(--brand-gray);
  margin-top:4px;
}

/* ---- 标签云 ---- */
.tag-cloud{display:flex;flex-wrap:wrap;gap:8px}
.tag{
  background:var(--brand-accent);
  color:var(--brand-gray);
  font-size:0.78rem;
  padding:4px 12px;
  border-radius:20px;
  border:1px solid var(--brand-border);
  transition:var(--transition);
}
.tag:hover{background:var(--brand-primary);color:#fff;border-color:var(--brand-primary)}

/* ---- 内页通用 ---- */
.page-hero{
  background:linear-gradient(135deg,var(--brand-navy),var(--brand-dark));
  padding:80px 0 60px;
  border-bottom:1px solid var(--brand-border);
}
.page-hero h1{
  font-size:2.5rem;
  font-weight:800;
  color:var(--brand-white);
  margin-bottom:12px;
}
.page-hero p{
  font-size:1rem;
  color:var(--brand-gray);
  max-width:600px;
}

/* ---- 分类标签过滤 ---- */
.filter-bar{
  display:flex;
  gap:10px;
  flex-wrap:wrap;
  margin-bottom:36px;
}
.filter-btn{
  padding:8px 20px;
  border-radius:20px;
  border:1px solid var(--brand-border);
  color:var(--brand-gray);
  font-size:0.875rem;
  cursor:pointer;
  transition:var(--transition);
  background:var(--brand-card);
}
.filter-btn:hover,.filter-btn.active{
  background:var(--brand-primary);
  color:#fff;
  border-color:var(--brand-primary);
}

/* ---- 滚动进度条 ---- */
.scroll-progress{
  position:fixed;
  top:0;left:0;
  height:3px;
  background:var(--brand-primary);
  z-index:9999;
  transition:width 0.1s;
  width:0%;
}

/* ---- 回到顶部 ---- */
.back-top{
  position:fixed;
  bottom:30px;
  right:30px;
  width:44px;
  height:44px;
  background:var(--brand-primary);
  border-radius:50%;
  display:flex;
  align-items:center;
  justify-content:center;
  cursor:pointer;
  opacity:0;
  transform:translateY(20px);
  transition:var(--transition);
  z-index:999;
  box-shadow:0 4px 16px rgba(255,107,0,0.4);
  font-size:1.1rem;
  color:#fff;
}
.back-top.show{opacity:1;transform:translateY(0)}
.back-top:hover{background:#E55A00;transform:translateY(-4px)}

/* ---- 懒加载占位 ---- */
img[loading="lazy"]{background:#111827}

/* ---- 响应式 ---- */
@media(max-width:1024px){
  .hero-title{font-size:2.8rem}
  .ai-grid{grid-template-columns:1fr}
  .contact-grid{grid-template-columns:1fr}
  .how-to-grid{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:768px){
  .nav-menu{display:none;flex-direction:column;position:absolute;top:70px;left:0;right:0;background:rgba(10,14,26,0.98);padding:20px;border-bottom:1px solid var(--brand-border)}
  .nav-menu.open{display:flex}
  .hamburger{display:flex}
  .header-search{display:none}
  .hero-title{font-size:2rem}
  .hero-stats{gap:24px}
  .stat-item .num{font-size:1.5rem}
  .section-gap{padding:50px 0}
  .section-title{font-size:1.6rem}
  .how-to-grid{grid-template-columns:1fr 1fr}
  .footer-grid{grid-template-columns:1fr}
  .footer-bottom{flex-direction:column;text-align:center}
  .video-grid{grid-template-columns:1fr}
  .expert-grid{grid-template-columns:1fr}
  .review-grid{grid-template-columns:1fr}
}
@media(max-width:480px){
  .hero-title{font-size:1.7rem}
  .hero-actions{flex-direction:column}
  .how-to-grid{grid-template-columns:1fr}
  .container{padding:0 16px}
}

/* ---- 动画 ---- */
@keyframes fadeInUp{
  from{opacity:0;transform:translateY(30px)}
  to{opacity:1;transform:translateY(0)}
}
.fade-in-up{animation:fadeInUp 0.6s ease both}
.delay-1{animation-delay:0.1s}
.delay-2{animation-delay:0.2s}
.delay-3{animation-delay:0.3s}
.delay-4{animation-delay:0.4s}

/* ---- 高亮文字 ---- */
.text-primary{color:var(--brand-primary)}
.text-gray{color:var(--brand-gray)}
.text-white{color:var(--brand-white)}
.bg-card{background:var(--brand-card)}
.border-card{border:1px solid var(--brand-border)}

/* ---- 视频播放模态框 ---- */
.video-modal{
  display:none;
  position:fixed;
  inset:0;
  background:rgba(0,0,0,0.9);
  z-index:9999;
  align-items:center;
  justify-content:center;
}
.video-modal.show{display:flex}
.modal-inner{
  position:relative;
  width:90%;
  max-width:900px;
  background:#000;
  border-radius:var(--radius-md);
  overflow:hidden;
}
.modal-close{
  position:absolute;
  top:12px;right:12px;
  width:36px;height:36px;
  background:rgba(255,255,255,0.1);
  border-radius:50%;
  display:flex;align-items:center;justify-content:center;
  cursor:pointer;
  color:#fff;
  font-size:1.2rem;
  z-index:10;
  transition:var(--transition);
}
.modal-close:hover{background:var(--brand-primary)}
.modal-video{
  width:100%;
  aspect-ratio:16/9;
  background:#111;
  display:flex;
  align-items:center;
  justify-content:center;
  color:var(--brand-gray);
  font-size:0.9rem;
}