/* ==========================================================================
   问鼎大舞台 — 瑞士网格设计系统
   浅色底 / 严格网格 / 红黑点缀 / 无衬线编辑排版
   ========================================================================== */

:root{
  --paper:#f5f4f1;
  --paper-deep:#eceae4;
  --white:#ffffff;
  --ink:#101010;
  --ink-soft:#38383a;
  --gray:#767470;
  --gray-light:#9a978f;
  --line:#dcdad2;
  --line-dark:#101010;
  --red:#e0281c;
  --red-deep:#b31c12;
  --max:1200px;
  --gutter:32px;
  --font:"Helvetica Neue","Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Arial,sans-serif;
}

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

html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
}

body{
  margin:0;
  overflow-x:hidden;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--font);
  font-size:16px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  text-rendering:optimizeLegibility;
}

img{max-width:100%;display:block;}
a{color:inherit;}

h1,h2,h3,h4,h5,h6{
  margin:0;
  font-weight:800;
  letter-spacing:-.02em;
  line-height:1.18;
}

p{margin:0 0 1em;}

::selection{background:var(--red);color:#fff;}

/* ==========================================================================
   布局基础
   ========================================================================== */

.container{
  width:100%;
  max-width:var(--max);
  margin:0 auto;
  padding-left:var(--gutter);
  padding-right:var(--gutter);
}

.section{
  position:relative;
  padding:104px 0;
  border-top:1px solid var(--line);
}

.section--tight{padding:72px 0;}
.section--flush{border-top:0;}

/* 章节标签 */
.section-label{
  display:inline-flex;
  align-items:center;
  gap:12px;
  margin:0 0 24px;
  padding:0;
  font-size:11px;
  font-weight:700;
  letter-spacing:.24em;
  line-height:1;
  color:var(--ink);
  text-transform:uppercase;
}

.section-label::before{
  content:"";
  display:block;
  width:28px;
  height:3px;
  background:var(--red);
  flex:0 0 auto;
}

.section-title{
  margin:0 0 20px;
  max-width:23em;
  font-size:clamp(26px,3.2vw,42px);
  font-weight:800;
  letter-spacing:-.025em;
  line-height:1.14;
}

.section-desc{
  margin:0 0 56px;
  max-width:640px;
  color:var(--gray);
  font-size:15px;
  line-height:1.95;
}

.section-title + .section-desc{margin-top:0;}

/* ==========================================================================
   顶部导航
   ========================================================================== */

.site-header{
  position:sticky;
  top:0;
  z-index:200;
  background:rgba(245,244,241,.94);
  -webkit-backdrop-filter:saturate(160%) blur(12px);
  backdrop-filter:saturate(160%) blur(12px);
  border-bottom:1px solid var(--line);
}

.header-inner{
  width:100%;
  max-width:var(--max);
  margin:0 auto;
  padding:0 var(--gutter);
  height:78px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:28px;
}

/* Logo */
.logo{
  display:inline-flex;
  align-items:center;
  gap:11px;
  font-size:17px;
  font-weight:800;
  letter-spacing:-.01em;
  color:var(--ink);
  text-decoration:none;
  white-space:nowrap;
  flex:0 0 auto;
}

.logo-icon{
  width:28px;
  height:28px;
  display:flex;
  align-items:center;
  justify-content:center;
  flex:0 0 auto;
  background:var(--red);
  color:#fff;
  font-size:13px;
  font-weight:800;
  line-height:1;
  letter-spacing:0;
  transition:background .24s ease, transform .24s ease;
}

.logo:hover .logo-icon{
  background:var(--ink);
  transform:rotate(-4deg);
}

/* 导航 */
.main-nav{
  display:flex;
  align-items:center;
  gap:36px;
  margin-left:auto;
}

.main-nav ul{
  display:flex;
  align-items:center;
  gap:36px;
  margin:0;
  padding:0;
  list-style:none;
}

.main-nav a{
  position:relative;
  display:inline-block;
  padding:6px 0;
  font-size:14px;
  font-weight:600;
  letter-spacing:.05em;
  color:var(--ink);
  text-decoration:none;
  transition:color .22s ease;
}

.main-nav a::after{
  content:"";
  position:absolute;
  left:0;
  bottom:0;
  width:0;
  height:2px;
  background:var(--red);
  transition:width .3s cubic-bezier(.2,.7,.3,1);
}

.main-nav a:hover{color:var(--red);}
.main-nav a:hover::after{width:100%;}

/* 导航按钮 */
.nav-cta{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  flex:0 0 auto;
  padding:12px 24px;
  background:var(--red);
  color:#fff;
  font-size:13px;
  font-weight:700;
  letter-spacing:.08em;
  text-decoration:none;
  border:1px solid var(--red);
  border-radius:0;
  transition:background .22s ease, border-color .22s ease, color .22s ease;
}

.nav-cta:hover{
  background:var(--ink);
  border-color:var(--ink);
  color:#fff;
}

/* 移动端菜单按钮 */
.menu-toggle{
  display:none;
  position:relative;
  width:46px;
  height:46px;
  padding:0;
  flex:0 0 auto;
  background:transparent;
  border:1px solid var(--ink);
  border-radius:0;
  cursor:pointer;
  transition:background .22s ease;
}

.menu-toggle::before,
.menu-toggle::after{
  content:"";
  position:absolute;
  left:13px;
  right:13px;
  height:2px;
  background:var(--ink);
  transition:background .22s ease;
}

.menu-toggle::before{
  top:17px;
  box-shadow:0 7px 0 var(--ink);
}

.menu-toggle::after{
  top:31px;
}

.menu-toggle:hover{background:var(--ink);}
.menu-toggle:hover::before,
.menu-toggle:hover::after{background:#fff;}
.menu-toggle:hover::before{box-shadow:0 7px 0 #fff;}

/* ==========================================================================
   首页 Hero
   ========================================================================== */

.hero{
  position:relative;
  display:grid;
  grid-template-columns:1fr;
  gap:56px;
  max-width:var(--max);
  margin:0 auto;
  padding:92px var(--gutter) 84px;
  border-bottom:1px solid var(--line);
}

.hero-content{min-width:0;}

.hero-eyebrow,
.hero-content .hero-eyebrow{
  display:inline-flex;
  align-items:center;
  gap:12px;
  margin:0 0 28px;
  font-size:12px;
  font-weight:700;
  letter-spacing:.22em;
  line-height:1;
  color:var(--red);
}

.hero-eyebrow::before{
  content:"";
  display:block;
  width:34px;
  height:1px;
  background:var(--red);
}

.hero-content h1{
  margin:0 0 26px;
  font-size:clamp(36px,5.2vw,68px);
  font-weight:800;
  letter-spacing:-.035em;
  line-height:1.06;
}

.hero-content h1 em{
  font-style:normal;
  color:var(--red);
}

.hero-content p{
  max-width:520px;
  margin:0 0 38px;
  color:var(--gray);
  font-size:16px;
  line-height:1.95;
}

.hero-buttons{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:16px;
}

.hero-image{
  position:relative;
  width:100%;
  min-height:280px;
  aspect-ratio:4 / 3;
  overflow:hidden;
  background:var(--paper-deep);
  border:1px solid var(--line);
}

.hero-image img{
  width:100%;
  height:100%;
  object-fit:cover;
}

.hero-image::after{
  content:"";
  position:absolute;
  right:0;
  bottom:0;
  width:64px;
  height:64px;
  background:var(--red);
  pointer-events:none;
}

/* ==========================================================================
   按钮
   ========================================================================== */

.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  padding:15px 34px;
  font-family:inherit;
  font-size:14px;
  font-weight:700;
  letter-spacing:.08em;
  line-height:1.2;
  text-decoration:none;
  border:1px solid transparent;
  border-radius:0;
  cursor:pointer;
  transition:background .22s ease, color .22s ease, border-color .22s ease;
}

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

.btn-primary:hover{
  background:var(--ink);
  border-color:var(--ink);
  color:#fff;
}

.btn-outline{
  background:transparent;
  border-color:var(--ink);
  color:var(--ink);
}

.btn-outline:hover{
  background:var(--ink);
  border-color:var(--ink);
  color:#fff;
}

/* ==========================================================================
   卡片网格
   ========================================================================== */

.cards-grid{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:0;
  border-top:1px solid var(--line-dark);
  border-left:1px solid var(--line);
  background:var(--line);
}

.category-card{
  position:relative;
  display:flex;
  flex-direction:column;
  padding:42px 34px 44px;
  background:var(--white);
  border-right:1px solid var(--line);
  border-bottom:1px solid var(--line);
  transition:background .26s ease;
}

.category-card::before{
  content:"";
  position:absolute;
  left:0;
  top:0;
  width:100%;
  height:3px;
  background:var(--red);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform .38s cubic-bezier(.2,.7,.3,1);
}

.category-card:hover{background:#fbfaf7;}
.category-card:hover::before{transform:scaleX(1);}

.card-icon{
  display:flex;
  align-items:center;
  justify-content:center;
  width:48px;
  height:48px;
  margin-bottom:28px;
  background:var(--ink);
  color:#fff;
  font-size:18px;
  font-weight:800;
  line-height:1;
  transition:background .26s ease;
}

.category-card:hover .card-icon{background:var(--red);}

.category-card h3{
  margin:0 0 12px;
  font-size:20px;
  font-weight:800;
  letter-spacing:-.015em;
}

.category-card p{
  margin:0 0 30px;
  color:var(--gray);
  font-size:14px;
  line-height:1.88;
}

.card-link{
  display:inline-flex;
  align-items:center;
  gap:9px;
  margin-top:auto;
  font-size:13px;
  font-weight:700;
  letter-spacing:.1em;
  color:var(--ink);
  text-decoration:none;
  transition:color .22s ease;
}

.card-link::after{
  content:"→";
  display:inline-block;
  font-size:14px;
  transition:transform .26s cubic-bezier(.2,.7,.3,1);
}

.card-link:hover{color:var(--red);}
.card-link:hover::after{transform:translateX(7px);}

/* ==========================================================================
   特性区块
   ========================================================================== */

.feature-block{
  display:grid;
  grid-template-columns:1fr;
  gap:48px;
  align-items:center;
}

.feature-image{
  position:relative;
  width:100%;
  aspect-ratio:5 / 4;
  overflow:hidden;
  background:var(--paper-deep);
  border:1px solid var(--line);
}

.feature-image img{
  width:100%;
  height:100%;
  object-fit:cover;
}

.feature-image::before{
  content:"";
  position:absolute;
  left:0;
  top:0;
  width:6px;
  height:88px;
  background:var(--red);
  z-index:2;
}

.feature-text{min-width:0;}

.feature-text h2,
.feature-text h3{
  margin:0 0 18px;
  font-size:clamp(24px,2.9vw,36px);
  font-weight:800;
  letter-spacing:-.025em;
  line-height:1.16;
}

.feature-text > p{
  margin:0 0 30px;
  color:var(--gray);
  font-size:15px;
  line-height:1.95;
}

.feature-list{
  margin:0;
  padding:0;
  list-style:none;
  border-top:1px solid var(--line);
}

.feature-list li{
  position:relative;
  padding:17px 0 17px 36px;
  border-bottom:1px solid var(--line);
  font-size:15px;
  line-height:1.7;
  color:var(--ink-soft);
}

.feature-list li::before{
  content:"";
  position:absolute;
  left:2px;
  top:26px;
  width:14px;
  height:2px;
  background:var(--red);
}

/* ==========================================================================
   数据条
   ========================================================================== */

.stats-bar{
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  background:var(--white);
  border-top:1px solid var(--line-dark);
  border-bottom:1px solid var(--line);
  border-left:1px solid var(--line);
}

.stat-item{
  padding:48px 28px 46px;
  border-right:1px solid var(--line);
}

.stat-item:last-child{border-right:none;}

.stat-number{
  display:block;
  font-size:clamp(34px,4.4vw,56px);
  font-weight:800;
  letter-spacing:-.035em;
  line-height:1;
  font-variant-numeric:tabular-nums;
  color:var(--ink);
}

.stat-number span,
.stat-number em{
  font-style:normal;
  color:var(--red);
}

.stat-label{
  display:block;
  margin-top:16px;
  font-size:12px;
  font-weight:600;
  letter-spacing:.2em;
  line-height:1.5;
  color:var(--gray);
}

/* ==========================================================================
   内容墙
   ========================================================================== */

.content-wall{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:1px;
  background:var(--line);
  border:1px solid var(--line);
}

.content-wall-item{
  position:relative;
  display:flex;
  flex-direction:column;
  background:var(--white);
  overflow:hidden;
  transition:background .26s ease;
}

.content-wall-item img{
  width:100%;
  aspect-ratio:16 / 10;
  object-fit:cover;
}

.content-wall-item:hover{background:#fbfaf7;}

.content-wall-body{
  position:relative;
  padding:28px 30px 34px;
  flex:1 1 auto;
}

.content-wall-body::before{
  content:"";
  position:absolute;
  left:30px;
  top:0;
  width:32px;
  height:2px;
  background:var(--red);
}

.content-wall-body h3{
  margin:10px 0 10px;
  font-size:18px;
  font-weight:800;
  letter-spacing:-.015em;
}

.content-wall-body p{
  margin:0;
  color:var(--gray);
  font-size:14px;
  line-height:1.88;
}

.content-wall-body .card-link{margin-top:20px;}

/* ==========================================================================
   问答
   ========================================================================== */

.faq-list{
  max-width:920px;
  border-top:1px solid var(--line-dark);
}

.faq-item{
  border-bottom:1px solid var(--line);
}

.faq-question{
  position:relative;
  display:block;
  margin:0;
  padding:26px 60px 26px 0;
  font-size:16px;
  font-weight:700;
  letter-spacing:-.005em;
  line-height:1.6;
  color:var(--ink);
  cursor:pointer;
  transition:color .22s ease;
}

.faq-question::after{
  content:"";
  position:absolute;
  right:6px;
  top:50%;
  width:14px;
  height:14px;
  transform:translateY(-50%);
  background-image:
    linear-gradient(var(--ink),var(--ink)),
    linear-gradient(var(--ink),var(--ink));
  background-size:14px 2px, 2px 14px;
  background-position:center, center;
  background-repeat:no-repeat;
  transition:background-image .24s ease, transform .3s ease;
}

.faq-item:hover .faq-question{color:var(--red);}
.faq-item:hover .faq-question::after{
  background-image:
    linear-gradient(var(--red),var(--red)),
    linear-gradient(var(--red),var(--red));
}

.faq-answer{
  margin:0;
  padding:0 60px 30px 0;
  color:var(--gray);
  font-size:14.5px;
  line-height:1.95;
}

.faq-item[open] .faq-question,
.faq-item.active .faq-question{color:var(--red);}

.faq-item[open] .faq-question::after,
.faq-item.active .faq-question::after{
  transform:translateY(-50%) rotate(90deg);
  background-image:
    linear-gradient(var(--red),var(--red)),
    linear-gradient(var(--red),var(--red));
}

/* ==========================================================================
   CTA 横幅
   ========================================================================== */

.cta-banner{
  position:relative;
  padding:92px 0;
  background:var(--ink);
  color:#fff;
  overflow:hidden;
}

.cta-banner::before{
  content:"";
  position:absolute;
  left:0;
  top:0;
  width:100%;
  height:4px;
  background:var(--red);
}

.cta-banner .container{
  position:relative;
  z-index:2;
}

.cta-banner h2{
  margin:0 0 18px;
  max-width:20em;
  font-size:clamp(26px,3.6vw,46px);
  font-weight:800;
  letter-spacing:-.03em;
  line-height:1.14;
  color:#fff;
}

.cta-banner h2 em{
  font-style:normal;
  color:#ff5a4d;
}

.cta-banner p{
  max-width:560px;
  margin:0 0 36px;
  color:rgba(255,255,255,.68);
  font-size:15px;
  line-height:1.95;
}

.cta-banner .hero-buttons{gap:16px;}

.cta-banner .btn-primary{
  background:var(--red);
  border-color:var(--red);
  color:#fff;
}

.cta-banner .btn-primary:hover{
  background:#fff;
  border-color:#fff;
  color:var(--ink);
}

.cta-banner .btn-outline{
  background:transparent;
  border-color:rgba(255,255,255,.45);
  color:#fff;
}

.cta-banner .btn-outline:hover{
  background:#fff;
  border-color:#fff;
  color:var(--ink);
}

/* ==========================================================================
   页脚
   ========================================================================== */

.site-footer{
  padding-top:76px;
  background:var(--white);
  border-top:1px solid var(--line);
}

.footer-grid{
  display:grid;
  grid-template-columns:1.6fr repeat(3,1fr);
  gap:48px;
  padding-bottom:60px;
}

.footer-brand{min-width:0;}

.footer-brand .logo{margin-bottom:22px;}

.footer-brand p{
  max-width:320px;
  margin:0 0 22px;
  color:var(--gray);
  font-size:14px;
  line-height:1.9;
}

.footer-brand .logo-icon{background:var(--red);}

.footer-col{min-width:0;}

.footer-col h4{
  margin:0 0 20px;
  font-size:11px;
  font-weight:700;
  letter-spacing:.22em;
  line-height:1;
  color:var(--ink);
}

.footer-col a{
  display:block;
  padding:7px 0;
  font-size:14px;
  color:var(--gray);
  text-decoration:none;
  transition:color .2s ease, padding-left .24s ease;
}

.footer-col a:hover{
  color:var(--red);
  padding-left:7px;
}

.footer-col p{
  margin:0 0 10px;
  font-size:14px;
  line-height:1.8;
  color:var(--gray);
}

.footer-bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  padding:24px 0 28px;
  border-top:1px solid var(--line);
  font-size:12.5px;
  letter-spacing:.05em;
  color:var(--gray-light);
}

.footer-bottom a{
  color:var(--gray);
  text-decoration:none;
  transition:color .2s ease;
}

.footer-bottom a:hover{color:var(--red);}

/* ==========================================================================
   文字工具类
   ========================================================================== */

.text-accent{color:var(--red);}

.text-center{text-align:center;}

.text-center .section-label{justify-content:center;}

.text-center .section-title,
.text-center .section-desc{
  margin-left:auto;
  margin-right:auto;
}

.seo-description{
  max-width:860px;
  margin:0 auto;
  color:var(--gray);
  font-size:14px;
  line-height:1.95;
  letter-spacing:.012em;
}

.mt-0{margin-top:0 !important;}
.mb-0{margin-bottom:0 !important;}

/* ==========================================================================
   响应式：平板
   ========================================================================== */

@media (max-width:1080px){

  :root{--gutter:26px;}

  .section{padding:88px 0;}

  .cards-grid{grid-template-columns:repeat(2,minmax(0,1fr));}

  .content-wall{grid-template-columns:repeat(2,minmax(0,1fr));}

  .footer-grid{
    grid-template-columns:1fr 1fr;
    gap:40px 32px;
  }

  .footer-brand{grid-column:1 / -1;}
}

@media (max-width:960px){

  .main-nav{
    position:absolute;
    top:78px;
    left:0;
    right:0;
    display:none;
    flex-direction:column;
    align-items:flex-start;
    gap:0;
    margin:0;
    padding:12px var(--gutter) 24px;
    background:var(--paper);
    border-bottom:1px solid var(--line);
    box-shadow:0 18px 30px -22px rgba(16,16,16,.35);
  }

  .main-nav.is-open{display:flex;}

  .main-nav ul{
    flex-direction:column;
    align-items:flex-start;
    gap:0;
    width:100%;
  }

  .main-nav ul li{width:100%;}

  .main-nav a{
    display:block;
    width:100%;
    padding:15px 0;
    font-size:15px;
    border-bottom:1px solid var(--line);
  }

  .main-nav a::after{display:none;}

  .nav-cta{display:none;}

  .menu-toggle{display:block;}

  .hero{
    padding:74px var(--gutter) 68px;
    gap:48px;
  }

  .stats-bar{grid-template-columns:repeat(2,minmax(0,1fr));}

  .stat-item{
    border-right:1px solid var(--line);
    border-bottom:1px solid var(--line);
  }

  .stat-item:nth-child(2n){border-right:none;}

  .stat-item:nth-last-child(-n+2){border-bottom:none;}
}

/* ==========================================================================
   响应式：桌面两栏增强
   ========================================================================== */

@media (min-width:961px){

  .hero{
    grid-template-columns:minmax(0,1.04fr) minmax(0,.96fr);
    gap:72px;
    align-items:center;
  }
}

@media (min-width:901px){

  .feature-block{
    grid-template-columns:1fr 1fr;
    gap:72px;
  }
}

/* ==========================================================================
   响应式：手机
   ========================================================================== */

@media (max-width:680px){

  :root{--gutter:20px;}

  body{font-size:15px;}

  .header-inner{height:68px;}

  .main-nav{top:68px;}

  .logo{font-size:16px;}

  .logo-icon{width:25px;height:25px;font-size:12px;}

  .section{padding:64px 0;}

  .section-desc{margin-bottom:38px;font-size:14.5px;}

  .section-label{margin-bottom:18px;font-size:10px;letter-spacing:.2em;}

  .hero{padding:56px var(--gutter) 56px;gap:38px;}

  .hero-content h1{font-size:clamp(30px,8.4vw,44px);letter-spacing:-.03em;}

  .hero-content p{font-size:15px;margin-bottom:30px;}

  .hero-buttons{gap:12px;}

  .btn{
    width:100%;
    padding:15px 24px;
  }

  .hero-image{aspect-ratio:3 / 2;min-height:220px;}

  .hero-image::after{width:46px;height:46px;}

  .cards-grid,
  .content-wall{grid-template-columns:1fr;}

  .category-card{padding:34px 24px 36px;}

  .card-icon{width:42px;height:42px;margin-bottom:22px;}

  .content-wall-body{padding:24px 24px 30px;}

  .content-wall-body::before{left:24px;}

  .feature-block{gap:34px;}

  .feature-list li{padding:15px 0 15px 30px;font-size:14.5px;}

  .feature-list li::before{top:24px;width:12px;}

  .stats-bar{grid-template-columns:1fr;}

  .stat-item{
    padding:34px 22px 32px;
    border-right:none;
    border-bottom:1px solid var(--line);
  }

  .stat-item:nth-last-child(-n+2){border-bottom:1px solid var(--line);}
  .stat-item:last-child{border-bottom:none;}

  .stat-number{font-size:40px;}

  .faq-question{
    padding:22px 46px 22px 0;
    font-size:15px;
  }

  .faq-answer{padding:0 0 24px 0;font-size:14px;}

  .faq-question::after{right:0;}

  .cta-banner{padding:64px 0;}

  .cta-banner p{margin-bottom:28px;}

  .site-footer{padding-top:56px;}

  .footer-grid{
    grid-template-columns:1fr;
    gap:34px;
    padding-bottom:40px;
  }

  .footer-bottom{
    flex-direction:column;
    align-items:flex-start;
    gap:8px;
    padding:20px 0 24px;
  }
}

/* ==========================================================================
   可访问性 / 动效降级
   ========================================================================== */

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
}