/* ============================================================
   dundununion.com v5 · 双联盟双轮驱动官网
   统一基础样式 · PC + 移动端双版本 · 深/浅双主题
   视觉硬定(第八章): 主色鎏金#E6C26E 背景#090E1A
   双色规范(总指挥铁定):
     深科技蓝背景 #090E1A → 白字#FFF + 金字#E6C26E
     白/浅背景        → 金字#E6C26E + 黑字#000
   ============================================================ */

/* ---------- 设计令牌 ---------- */
:root{
  /* 品牌色 */
  --gold:#E6C26E;          /* 鎏金 主强调 */
  --gold-soft:#f0d9a0;
  --blue:#4A90E2;
  --green:#7CC576;
  --purple:#9B59B6;

  /* 深主题(默认) */
  --bg:#090E1A;
  --bg-elev:#0F1626;
  --bg-card:#121B2E;
  --line:rgba(230,194,110,.18);
  --txt:#FFFFFF;
  --txt-dim:#A9B4C6;
  --txt-mute:#6B7689;
  --btn-gold-bg:var(--gold);
  --btn-gold-txt:#0A0F1C;
  --btn-outline:rgba(230,194,110,.55);
}

/* 浅主题 */
body.theme-light{
  --bg:#F7F4EC;            /* 米白暖底 */
  --bg-elev:#FFFFFF;
  --bg-card:#FFFFFF;
  --line:rgba(20,20,20,.12);
  --txt:#111111;           /* 黑字 */
  --txt-dim:#444444;
  --txt-mute:#777777;
  --btn-gold-bg:var(--gold);
  --btn-gold-txt:#0A0F1C;
  --btn-outline:rgba(20,20,20,.35);
}

/* ---------- 基础重置 ---------- */
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:"Noto Sans SC","Outfit",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  background:var(--bg);
  color:var(--txt);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  transition:background .35s ease,color .35s ease;
  overflow-x:hidden;
}
h1,h2,h3,h4{font-family:"Outfit","Noto Sans SC",sans-serif;line-height:1.25;font-weight:800}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.mono{font-family:"JetBrains Mono",monospace}
.gold{color:var(--gold)}
.wrap{max-width:1200px;margin:0 auto;padding:0 24px}
section{padding:80px 0}
.center{text-align:center}

/* ---------- 顶部导航 ---------- */
.nav{
  position:sticky;top:0;z-index:100;
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 24px;
  background:color-mix(in srgb,var(--bg) 86%,transparent);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--line);
}
.nav .brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:19px}
.nav .brand .logo{
  width:34px;height:34px;border-radius:4px;
  object-fit:cover;
  box-shadow:0 0 0 1px rgba(255,255,255,.15) inset;
}
.nav .brand b{color:var(--gold)}
.nav-links{display:flex;gap:6px;align-items:center}
.nav-links a{
  padding:8px 13px;border-radius:9px;font-size:14.5px;color:var(--txt-dim);
  transition:.2s;white-space:nowrap;
}
.nav-links a:hover,.nav-links a.active{color:var(--txt);background:var(--bg-card)}
.nav-right{display:flex;align-items:center;gap:10px}
.btn-gold{
  background:var(--btn-gold-bg);color:var(--btn-gold-txt);
  padding:9px 18px;border-radius:10px;font-weight:700;font-size:14px;
  border:none;cursor:pointer;transition:.2s;
}
.btn-gold:hover{transform:translateY(-1px);box-shadow:0 6px 18px rgba(230,194,110,.35)}
.btn-outline{
  background:transparent;color:var(--txt);
  padding:9px 18px;border-radius:10px;font-weight:600;font-size:14px;
  border:1px solid var(--btn-outline);cursor:pointer;transition:.2s;
}
.btn-outline:hover{border-color:var(--gold);color:var(--gold)}
.theme-toggle{
  width:42px;height:42px;border-radius:10px;border:1px solid var(--line);
  background:var(--bg-card);color:var(--gold);cursor:pointer;font-size:18px;
  display:flex;align-items:center;justify-content:center;transition:.2s;
}
.theme-toggle:hover{border-color:var(--gold)}
.hamburger{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:8px}
.hamburger span{width:24px;height:2px;background:var(--txt);border-radius:2px;transition:.3s}

/* ---------- Hero ---------- */
.hero{
  position:relative;padding:120px 0 90px;text-align:center;overflow:hidden;
  background:
    radial-gradient(900px 500px at 50% -10%,rgba(230,194,110,.14),transparent 60%),
    radial-gradient(700px 400px at 80% 20%,rgba(74,144,226,.10),transparent 60%);
}
.hero .tag{
  display:inline-block;padding:6px 16px;border:1px solid var(--gold);
  border-radius:999px;color:var(--gold);font-size:13px;letter-spacing:.5px;margin-bottom:22px;
}
.hero h1{
  font-size:clamp(34px,5.4vw,62px);letter-spacing:-.5px;margin-bottom:20px;
}
.hero h1 .gold{color:var(--gold)}
.hero .sub{font-size:clamp(15px,2vw,19px);color:var(--txt-dim);max-width:760px;margin:0 auto 14px}
.hero .sub2{font-size:15px;color:var(--txt-mute);margin-bottom:34px}
.hero .cta{display:flex;gap:16px;justify-content:center;flex-wrap:wrap;margin-bottom:30px}
.hero .counter{
  display:inline-flex;gap:26px;flex-wrap:wrap;justify-content:center;
  padding:16px 28px;border:1px solid var(--line);border-radius:14px;background:var(--bg-card);
}
.hero .counter .num{font-family:"JetBrains Mono";font-size:26px;font-weight:700;color:var(--gold)}
.hero .counter .lbl{font-size:12.5px;color:var(--txt-mute)}
.hero .assist{margin-top:18px;font-size:13px;color:var(--txt-mute)}

/* ---------- 通用区块标题 ---------- */
.sec-head{text-align:center;margin-bottom:48px}
.sec-head .tag{color:var(--gold);font-size:13px;letter-spacing:1px;text-transform:uppercase}
.sec-head h2{font-size:clamp(26px,3.6vw,40px);margin:10px 0}
.sec-head h1{font-size:clamp(26px,3.6vw,40px);margin:10px 0;line-height:1.18}
.sec-head p{color:var(--txt-dim);max-width:640px;margin:8px auto 0}

/* ---------- 卡片网格 ---------- */
.grid{display:grid;gap:22px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
.card{
  background:var(--bg-card);border:1px solid var(--line);border-radius:16px;
  padding:26px;transition:.25s;position:relative;overflow:hidden;
}
.card:hover{transform:translateY(-4px);border-color:var(--gold);box-shadow:0 14px 40px rgba(0,0,0,.35)}
.card .ico{
  width:48px;height:48px;border-radius:12px;display:flex;align-items:center;justify-content:center;
  background:rgba(230,194,110,.12);color:var(--gold);font-size:22px;margin-bottom:16px;
}
.card h3{font-size:19px;margin-bottom:10px}
.card p{color:var(--txt-dim);font-size:14.5px}
.card .more{display:inline-block;margin-top:16px;color:var(--gold);font-weight:600;font-size:14px}

/* 大联盟卡 */
.big-card{
  background:linear-gradient(160deg,var(--bg-card),var(--bg-elev));
  border:1px solid var(--line);border-radius:20px;padding:38px;position:relative;overflow:hidden;
}
.big-card .badge{
  display:inline-block;padding:5px 14px;border-radius:999px;font-size:12.5px;font-weight:600;
  background:rgba(230,194,110,.14);color:var(--gold);margin-bottom:18px;
}
.big-card h3{font-size:26px;margin-bottom:12px}
.big-card ul{list-style:none;margin:16px 0 24px}
.big-card ul li{padding:7px 0 7px 26px;position:relative;color:var(--txt-dim);font-size:15px}
.big-card ul li::before{content:"◆";position:absolute;left:0;color:var(--gold);font-size:11px;top:9px}
.big-card.link{cursor:pointer;transition:border-color .25s,transform .25s,box-shadow .25s}
.big-card.link:hover{border-color:var(--gold);transform:translateY(-4px);box-shadow:0 14px 40px rgba(230,194,110,.14)}
.big-card.link .btn-gold,.big-card.link .btn-outline{margin-top:8px}

/* 数据条 */
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;text-align:center}
.stats .num{font-family:"JetBrains Mono";font-size:38px;font-weight:800;color:var(--gold)}
.stats .lbl{color:var(--txt-dim);font-size:14px;margin-top:6px}

/* 表格 */
.tbl{width:100%;border-collapse:collapse;margin-top:10px;font-size:14.5px;overflow:hidden;border-radius:12px}
.tbl th,.tbl td{padding:13px 16px;text-align:left;border-bottom:1px solid var(--line)}
.tbl th{background:var(--bg-elev);color:var(--gold);font-weight:700}
.tbl tr:hover td{background:var(--bg-card)}
.tbl-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:12px}

/* 步骤 */
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.step{background:var(--bg-card);border:1px solid var(--line);border-radius:14px;padding:24px;position:relative}
.step .n{font-family:"JetBrains Mono";font-size:30px;color:var(--gold);font-weight:800;opacity:.5}
.step h4{margin:8px 0 8px;font-size:17px}
.step p{color:var(--txt-dim);font-size:14px}

/* 留资表单 */
.lead-form{max-width:520px;margin:0 auto;background:var(--bg-card);border:1px solid var(--line);
  border-radius:18px;padding:34px}
.lead-form h3{text-align:center;margin-bottom:6px;font-size:22px}
.lead-form p{text-align:center;color:var(--txt-dim);font-size:14px;margin-bottom:22px}
.lead-form label{display:block;font-size:13.5px;color:var(--txt-dim);margin:14px 0 7px}
.lead-form input,.lead-form select{
  width:100%;padding:12px 14px;border-radius:10px;border:1px solid var(--line);
  background:var(--bg);color:var(--txt);font-size:15px;font-family:inherit;
}
.lead-form input:focus,.lead-form select:focus{outline:none;border-color:var(--gold)}
.lead-form .btn-gold{width:100%;margin-top:22px;padding:13px;font-size:15px}
.lead-ok{display:none;text-align:center;color:var(--green);font-weight:600;padding:14px}

/* FAQ */
.faq-item{border:1px solid var(--line);border-radius:12px;margin-bottom:12px;overflow:hidden;background:var(--bg-card)}
.faq-q{padding:16px 20px;cursor:pointer;font-weight:600;display:flex;justify-content:space-between;gap:12px}
.faq-q .ar{color:var(--gold);transition:.3s}
.faq-a{max-height:0;overflow:hidden;transition:.35s;padding:0 20px;color:var(--txt-dim);font-size:14.5px}
.faq-item.open .faq-a{max-height:300px;padding:0 20px 18px}
.faq-item.open .faq-q .ar{transform:rotate(180deg)}

/* 面包屑 */
.crumb{padding:22px 0 0;font-size:13.5px;color:var(--txt-mute)}
.crumb a:hover{color:var(--gold)}
.crumb span{margin:0 8px;opacity:.5}

/* 返回按钮(哪里来跳回哪里去) */
.back-btn{
  display:inline-flex;align-items:center;gap:8px;margin:26px 0 0;
  padding:10px 20px;border-radius:10px;cursor:pointer;
  background:var(--bg-card);border:1px solid var(--line);
  color:var(--txt);font-size:14.5px;font-weight:600;transition:.2s;
}
.back-btn:hover{border-color:var(--gold);color:var(--gold);transform:translateX(-2px)}
.back-btn .ar{color:var(--gold);font-size:16px;line-height:1}

/* 可点击卡片(整卡跳转) */
.card.link{cursor:pointer;transition:.25s}
.card.link:hover{transform:translateY(-4px);border-color:var(--gold);box-shadow:0 14px 40px rgba(0,0,0,.35)}
.card.link .more{display:inline-block;margin-top:16px;color:var(--gold);font-weight:600;font-size:14px}

/* Footer */
.footer{border-top:1px solid var(--line);padding:54px 0 30px;margin-top:40px;background:var(--bg-elev)}
.footer .cols{display:grid;grid-template-columns:1.6fr 1fr 1fr 1fr;gap:30px}
.footer h4{font-size:15px;margin-bottom:14px;color:var(--gold)}
.footer a{display:block;color:var(--txt-dim);font-size:14px;padding:5px 0}
.footer a:hover{color:var(--txt)}
.footer .copy{border-top:1px solid var(--line);margin-top:34px;padding-top:20px;
  font-size:13px;color:var(--txt-mute);display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px}
.footer .beian{color:var(--txt-mute)}

/* 入场动画 */
.reveal{opacity:0;transform:translateY(24px);transition:.7s cubic-bezier(.2,.7,.2,1)}
.reveal.in-view{opacity:1;transform:none}

/* P0-1：空字段显式标注 */
.field-empty{color:var(--txt-mute);font-style:italic;font-size:13px}

/* P0-2：骨架屏（首屏加载占位，杜绝白屏） */
.skeleton-wrap{padding:6px 4px}
.skeleton-row{height:46px;margin-bottom:10px;border-radius:8px;
  background:linear-gradient(90deg,rgba(255,255,255,.04) 25%,rgba(230,194,110,.12) 37%,rgba(255,255,255,.04) 63%);
  background-size:400% 100%;animation:sk-shimmer 1.2s ease-in-out infinite}
@keyframes sk-shimmer{0%{background-position:100% 0}100%{background-position:-100% 0}}

/* ===== 墩墩AI 悬浮客服（黑金主题）===== */
#dunChatBtn{position:fixed;right:22px;bottom:24px;z-index:99999;display:flex;align-items:center;gap:8px;
  padding:12px 18px;border-radius:999px;background:linear-gradient(135deg,var(--gold),#caa24f);
  color:#1a1206;font-weight:700;font-size:15px;cursor:pointer;box-shadow:0 8px 28px rgba(230,194,110,.4);
  transition:.2s;user-select:none}
#dunChatBtn:hover{transform:scale(1.06);box-shadow:0 12px 34px rgba(230,194,110,.55)}
#dunChatBtn:active{transform:scale(.97)}
#dunChatBtn .ic{font-size:20px}
#dunChatBox{position:fixed;right:22px;bottom:90px;z-index:99999;width:370px;max-width:calc(100vw - 28px);
  height:540px;max-height:calc(100vh - 120px);display:flex;flex-direction:column;
  background:var(--bg-card);border:1px solid var(--gold);border-radius:16px;overflow:hidden;
  box-shadow:0 20px 60px rgba(0,0,0,.55);transition:.25s;font-size:14px}
#dunChatBox.min{opacity:0;transform:translateY(16px) scale(.96);pointer-events:none;visibility:hidden}
.ch-head{display:flex;align-items:center;justify-content:space-between;padding:14px 16px;
  background:linear-gradient(135deg,var(--gold),#caa24f);color:#1a1206;cursor:move}
.ch-title{font-weight:800;font-size:15px}
.ch-acts span{margin-left:12px;cursor:pointer;font-size:18px;line-height:1;opacity:.8}
.ch-acts span:hover{opacity:1}
.ch-body{flex:1;overflow-y:auto;padding:16px;background:var(--bg)}
.ch-msg{display:flex;gap:8px;margin-bottom:14px;align-items:flex-start}
.ch-msg.mine{justify-content:flex-end}
.ch-msg .av{width:30px;height:30px;border-radius:8px;background:rgba(230,194,110,.15);display:flex;align-items:center;justify-content:center;font-size:16px;flex-shrink:0}
.ch-msg .bub{max-width:78%;padding:10px 13px;border-radius:12px;line-height:1.6;word-break:break-word}
.ch-msg.bot .bub{background:var(--bg-elev);border:1px solid var(--line);color:var(--txt)}
.ch-msg.mine .bub{background:var(--gold);color:#1a1206;border-top-right-radius:4px}
.ch-msg.bot .bub{border-top-left-radius:4px}
.ch-msg .bub p{margin:0 0 6px}.ch-msg .bub p:last-child{margin:0}
.ch-msg .bub ul{margin:6px 0;padding-left:18px}.ch-msg .bub li{margin:3px 0}
.ch-msg .bub b{color:var(--gold)}
.ch-msg.mine .bub b{color:#1a1206}
.ch-foot{display:flex;gap:8px;padding:12px;border-top:1px solid var(--line);align-items:flex-end}
.ch-foot textarea{flex:1;resize:none;max-height:80px;min-height:38px;padding:9px 11px;border-radius:10px;
  background:var(--bg);border:1px solid var(--line);color:var(--txt);font-family:inherit;font-size:14px;line-height:1.4}
.ch-foot textarea:focus{outline:none;border-color:var(--gold)}
.ch-foot button{padding:9px 14px;border-radius:10px;border:none;font-weight:700;cursor:pointer;font-size:13px}
#chSend{background:var(--gold);color:#1a1206}
#chClear{background:var(--bg-elev);color:var(--txt-dim);border:1px solid var(--line)!important}
.typing{display:flex;gap:4px;align-items:center}
.typing i{width:7px;height:7px;border-radius:50%;background:var(--gold);opacity:.6;animation:chblink 1s infinite}
.typing i:nth-child(2){animation-delay:.2s}.typing i:nth-child(3){animation-delay:.4s}
@keyframes chblink{0%,100%{opacity:.3;transform:translateY(0)}50%{opacity:1;transform:translateY(-3px)}}

@media (max-width:768px){
  #dunChatBtn{right:14px;bottom:16px;padding:10px 14px;font-size:14px}
  #dunChatBox{right:10px;left:10px;bottom:10px;width:auto;height:auto;max-height:80vh;bottom:74px}
  #dunChatBox.min{opacity:0;visibility:hidden}
}

/* ============================================================
   移动端(9:16) · 全量适配 · 必须在末尾级联胜出
   ============================================================ */
@media (max-width:768px){
  .wrap{padding:0 18px}
  section{padding:56px 0}
  .nav-links{
    position:fixed;top:64px;left:0;right:0;flex-direction:column;gap:0;
    background:var(--bg-elev);border-bottom:1px solid var(--line);
    padding:10px 18px 20px;transform:translateY(-130%);transition:.35s;z-index:99;
    box-shadow:0 14px 30px rgba(0,0,0,.4);
  }
  .nav-links.show{transform:translateY(0)}
  .nav-links a{padding:13px 8px;width:100%;border-bottom:1px solid var(--line);font-size:15.5px}
  .hamburger{display:flex}
  .nav-right .btn-outline{display:none}
  .hero{padding:84px 0 60px}
  .hero .cta{flex-direction:column;align-items:stretch}
  .hero .cta .btn-gold,.hero .cta .btn-outline{padding:13px;text-align:center}
  .hero .counter{gap:14px;padding:14px}
  .hero .counter .num{font-size:21px}
  .grid-2,.grid-3,.grid-4{grid-template-columns:1fr}
  .stats{grid-template-columns:repeat(2,1fr);gap:16px}
  .stats .num{font-size:30px}
  .steps{grid-template-columns:1fr}
  .big-card{padding:28px}
  .footer .cols{grid-template-columns:1fr 1fr}
  .footer .copy{flex-direction:column}
  .tbl{font-size:13px}
  .tbl th,.tbl td{padding:10px 11px}
}
@media (max-width:420px){
  .hero h1{font-size:30px}
  .footer .cols{grid-template-columns:1fr}
}