/* ============================================================
   方寸AI成长学伴 · V3
   EITS 新一代具身智能教学系统官网
   深色星轨 × 纸感阅读区
   ============================================================ */

:root{
  /* 深色星轨 */
  --space:#05070f;
  --space-2:#0a0f1e;
  --space-card:#0e1426;
  --line-dark:rgba(120,160,220,.22);
  --txt-light:#e8ecf5;
  --txt-light-m:#97a3c2;
  --gold:#ffd166;
  --gold-deep:#f0a92e;
  --blue:#5f86d6;
  --blue-bright:#7aa2f0;

  /* 浅色阅读 */
  --paper:#f6f7fa;
  --paper-alt:#eef0f6;
  --card:#ffffff;
  --ink:#141826;
  --ink-m:#5a6478;
  --line:rgba(20,24,38,.10);

  --r:12px;
  --r-lg:18px;
  --r-pill:999px;
  --sans:"SF Pro Text","PingFang SC","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
}

*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:var(--sans);
  background:var(--space);
  color:var(--txt-light);
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
.hl{color:var(--gold)}

/* ---------- 通用按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  font-family:var(--sans);font-weight:600;font-size:14px;letter-spacing:.4px;
  border-radius:var(--r-pill);padding:11px 22px;border:1px solid transparent;
  cursor:pointer;transition:transform .15s,box-shadow .15s,background .15s;
  white-space:nowrap;
}
.btn-gold{
  background:linear-gradient(135deg,var(--gold),var(--gold-deep));
  color:#241a04;
  box-shadow:0 6px 20px rgba(240,169,46,.30);
}
.btn-gold:hover{transform:translateY(-1px);box-shadow:0 9px 26px rgba(240,169,46,.40)}
.btn-ghost{background:rgba(255,255,255,.06);border-color:rgba(120,160,220,.45);color:var(--txt-light)}
.btn-ghost:hover{background:rgba(255,255,255,.12)}
.btn-lg{padding:14px 28px;font-size:15px}
.btn-block{width:100%}

/* ---------- 标签 ---------- */
.eyebrow,.kicker{
  display:inline-block;font-size:12px;font-weight:600;letter-spacing:1.5px;
  padding:6px 14px;border-radius:var(--r-pill);
  background:rgba(120,160,220,.12);border:1px solid var(--line-dark);
  color:var(--blue-bright);
}
.kicker-light{background:rgba(255,209,102,.10);border-color:rgba(255,209,102,.4);color:var(--gold)}
h2{font-size:clamp(26px,3.4vw,38px);line-height:1.3;letter-spacing:.5px;margin:18px 0 14px}
.sec-sub{color:var(--txt-light-m);font-size:15px;max-width:720px}

/* ================= 导航 ================= */
.nav{position:fixed;top:0;left:0;right:0;z-index:100;transition:background .25s,border-color .25s;
  border-bottom:1px solid transparent}
.nav.scrolled{background:rgba(5,7,15,.82);backdrop-filter:blur(12px);border-bottom-color:var(--line-dark)}
.nav-in{max-width:1180px;margin:0 auto;padding:14px 24px;display:flex;align-items:center;gap:28px}
.brand{display:flex;align-items:center;gap:10px;font-size:16px}
.brand b{font-weight:700}
.brand-mark{
  width:30px;height:30px;border-radius:9px;flex:0 0 auto;
  background:linear-gradient(135deg,#5f86d6,#8b6fe0);
  position:relative;
}
.brand-mark::after{
  content:"";position:absolute;left:50%;top:50%;transform:translate(-50%,-42%);
  width:11px;height:11px;border-radius:50%;
  background:#ffd166;
  box-shadow:0 0 0 3px rgba(255,209,102,.25);
}
.nav-links{display:flex;gap:26px;margin-left:auto}
.nav-links a{font-size:14px;color:var(--txt-light-m);transition:color .15s}
.nav-links a:hover{color:var(--txt-light)}
.nav-act{display:flex;align-items:center;gap:12px}
.hamburger{display:none;flex-direction:column;gap:5px;background:none;border:none;cursor:pointer;padding:6px}
.hamburger span{width:22px;height:2px;background:var(--txt-light);border-radius:2px;transition:.2s}
.hamburger[aria-expanded="true"] span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.hamburger[aria-expanded="true"] span:nth-child(2){opacity:0}
.hamburger[aria-expanded="true"] span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

.mobile-menu{display:none;flex-direction:column;padding:8px 24px 20px;background:rgba(5,7,15,.96);backdrop-filter:blur(12px)}
.mobile-menu a{padding:13px 4px;font-size:15px;border-bottom:1px solid var(--line-dark);color:var(--txt-light)}
.mobile-menu .mm-cta{margin-top:14px;border-bottom:none;text-align:center;background:linear-gradient(135deg,var(--gold),var(--gold-deep));
  color:#241a04;border-radius:var(--r-pill);padding:13px;font-weight:600}
.mobile-menu[hidden]{display:none}

/* ================= 第一屏 ================= */
.hero{position:relative;min-height:100vh;display:flex;flex-direction:column;justify-content:center;
  padding:108px 24px 70px;
  background:
   radial-gradient(1100px 600px at 78% 12%,rgba(95,134,214,.16),transparent 60%),
   radial-gradient(900px 560px at 12% 88%,rgba(139,111,224,.10),transparent 60%),
   var(--space);
}
.hero-in{max-width:1180px;margin:0 auto;width:100%;display:grid;grid-template-columns:minmax(0,1.02fr) minmax(0,.98fr);gap:56px;align-items:center}
.hero-copy h1{font-size:clamp(32px,4.4vw,52px);line-height:1.22;letter-spacing:.8px;margin:20px 0 20px;font-weight:700}
.hero-sub{font-size:16px;color:var(--txt-light-m);max-width:520px}
.hero-sub strong{color:var(--txt-light);font-weight:600}
.hero-cta{display:flex;gap:14px;margin:28px 0 18px;flex-wrap:wrap}
.microtrust{display:flex;flex-wrap:wrap;gap:0;list-style:none;font-size:12.5px;color:var(--txt-light-m)}
.microtrust li{padding-right:16px;margin-right:16px;position:relative}
.microtrust li:not(:last-child)::after{content:"";position:absolute;right:0;top:50%;transform:translateY(-50%);
  width:4px;height:4px;border-radius:50%;background:var(--gold)}

.hero-visual{position:relative}
.hero-visual iframe{
  width:100%;height:560px;border:1px solid var(--line-dark);border-radius:var(--r-lg);
  background:#05070f;box-shadow:0 30px 80px rgba(0,0,0,.5),0 0 0 1px rgba(255,255,255,.03);
}
.frame-tag{position:absolute;left:50%;bottom:-14px;transform:translateX(-50%);white-space:nowrap;
  font-size:11.5px;color:var(--txt-light-m);background:var(--space-2);border:1px solid var(--line-dark);
  padding:5px 14px;border-radius:var(--r-pill)}

.scroll-hint{position:absolute;bottom:22px;left:50%;transform:translateX(-50%);
  font-size:13px;color:var(--txt-light-m);white-space:nowrap;transition:color .15s}
.scroll-hint:hover{color:var(--gold)}

/* ================= 架构总览 ================= */
.arch{background:linear-gradient(180deg,var(--space),var(--space-2) 60%,var(--space));
  padding:100px 0 90px;text-align:center}
.arch .sec-sub{margin:0 auto}

.arch-diagram{position:relative;max-width:860px;height:440px;margin:54px auto 30px}
.arch-core{
  position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);
  width:200px;height:200px;border-radius:50%;
  background:radial-gradient(circle at 35% 30%,#1a2340,#0b1122 70%);
  border:1.5px solid rgba(255,209,102,.55);
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;
  box-shadow:0 0 50px rgba(255,209,102,.12),inset 0 0 30px rgba(95,134,214,.18);
  z-index:2;
}
.core-badge{font-size:26px;font-weight:700;color:var(--gold);letter-spacing:4px}
.arch-core{width:224px;height:224px}
.arch-core p{font-size:12.5px;color:var(--txt-light);padding:0 16px}
.arch-core span{font-size:10.5px;color:var(--txt-light-m);padding:0 20px;line-height:1.6}
.arch-core em{font-style:normal;font-size:10px;letter-spacing:2.5px;color:rgba(255,209,102,.75);margin-top:5px}

.arch-card{
  position:absolute;width:190px;padding:18px 16px;border-radius:var(--r);
  background:rgba(14,20,38,.85);border:1px solid var(--line-dark);
  display:flex;flex-direction:column;gap:4px;transition:transform .15s,border-color .15s,box-shadow .15s;
  backdrop-filter:blur(6px);
}
.arch-card b{font-size:16px;color:var(--txt-light)}
.arch-card span{font-size:11.5px;color:var(--txt-light-m)}
.arch-card i{font-style:normal;font-size:9.5px;letter-spacing:1.6px;color:#5f78b8;margin-top:3px}
.arch-card:hover{transform:scale(1.04);border-color:var(--gold);box-shadow:0 12px 30px rgba(0,0,0,.4)}
.a1{left:0;top:6%}
.a2{right:0;top:6%}
.a3{left:0;bottom:6%}
.a4{right:0;bottom:6%}

/* 装饰连接线 */
.arch-ring{position:absolute;inset:0}
.arch-ring::before,.arch-ring::after{
  content:"";position:absolute;border:1px dashed rgba(120,160,220,.25);border-radius:50%;
  left:50%;top:50%;transform:translate(-50%,-50%);pointer-events:none;
}
.arch-ring::before{width:560px;height:380px}
.arch-ring::after{width:330px;height:250px}

.flywheel{
  margin-top:20px;background:rgba(14,20,38,.7);border:1px solid var(--line-dark);
  border-radius:var(--r-lg);padding:22px 26px;display:flex;gap:20px;align-items:center;text-align:left;
}
.fw-name{flex:0 0 auto;background:linear-gradient(135deg,var(--gold),var(--gold-deep));color:#241a04;
  font-size:13px;font-weight:700;padding:8px 16px;border-radius:var(--r-pill)}
.flywheel p{font-size:14px;color:var(--txt-light-m)}
.flywheel strong{color:var(--txt-light)}

/* ================= 模型区块（浅色） ================= */
.model{background:var(--paper);color:var(--ink);padding:96px 0}
.model-alt{background:var(--paper-alt)}
.model-head{margin-bottom:34px}
.model-no{display:inline-block;font-size:12px;font-weight:700;letter-spacing:2px;color:#3d63c4;
  background:rgba(61,99,196,.10);padding:5px 13px;border-radius:var(--r-pill);margin-bottom:14px}
.model h2{color:var(--ink);margin:0}
.model .hl{color:#c8860c}

/* 痛点卡 */
.pains{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;margin-bottom:40px}
.pain-card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:20px 22px;font-size:14.5px;color:#3a4258;
  position:relative;
}
.pain-card::before{content:"“";position:absolute;left:12px;top:-4px;font-size:34px;color:#c6cde0;font-family:Georgia,serif}

/* 机制区 */
.mech{background:var(--card);border:1px solid var(--line);border-radius:var(--r-lg);padding:34px}
.mech-split{display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,.9fr);gap:36px;align-items:center}
.ef-title{font-size:14px;font-weight:700;color:var(--ink);margin-bottom:16px}

/* 四步骤 */
.steps{list-style:none;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:18px;margin-bottom:34px}
.steps li{background:var(--paper);border:1px solid var(--line);border-radius:var(--r);padding:18px 16px;min-width:0}
.steps b{display:block;font-size:14px;color:var(--ink);margin-bottom:6px}
.steps span{font-size:12.5px;color:var(--ink-m);line-height:1.7}

/* 病根链可视化 */
.chain-vis{position:relative;display:flex;align-items:center;justify-content:center;gap:24px;
  background:linear-gradient(135deg,#0b1122,#141d36);border-radius:var(--r);padding:34px 24px}
.chain-tag{position:absolute;top:12px;left:14px;font-size:10.5px;letter-spacing:1px;color:var(--gold);
  border:1px solid rgba(255,209,102,.4);padding:3px 11px;border-radius:var(--r-pill)}
.chain-node{background:rgba(255,255,255,.05);border-radius:var(--r);padding:18px 24px;text-align:center;min-width:150px}
.chain-node b{display:block;font-size:11px;letter-spacing:1.5px;margin-bottom:5px}
.chain-node span{display:block;font-size:16px;color:var(--txt-light);font-weight:600;margin-bottom:3px}
.chain-node em{font-style:normal;font-size:11.5px;color:var(--txt-light-m)}
.cn-hi{border:1px solid rgba(122,162,240,.5)}
.cn-hi b{color:var(--blue-bright)}
.cn-lo{border:1px solid rgba(255,209,102,.55)}
.cn-lo b{color:var(--gold)}
.chain-line{width:90px;height:2px;background:repeating-linear-gradient(90deg,var(--gold) 0 8px,transparent 8px 16px);
  position:relative;flex:0 0 auto}
.chain-line span{position:absolute;right:-2px;top:50%;transform:translateY(-50%);
  border-left:9px solid var(--gold);border-top:6px solid transparent;border-bottom:6px solid transparent}
@media (prefers-reduced-motion:no-preference){
  .chain-line{background-size:16px 2px;animation:flowx .8s linear infinite}
  @keyframes flowx{to{background-position:16px 0}}
}

/* 科学依据条 */
.evidence-row{margin-top:22px;background:rgba(61,99,196,.07);border-left:3px solid #3d63c4;
  border-radius:0 var(--r) var(--r) 0;padding:12px 18px;font-size:12.5px;color:#4a546c}
.evidence-row b{color:#2f54b0}
.value-line{margin-top:24px;text-align:center;font-size:17px;color:var(--ink)}
.value-line b{color:#b3730a}

/* 用户模型 · 事件流 */
.ef-items{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:6px}
.ef-items span{background:var(--paper);border:1px solid var(--line);border-radius:var(--r-pill);
  font-size:13px;padding:7px 16px;color:#3a4258}
.ef-arrow{text-align:center;color:#a0a8b8;font-size:12px;margin:10px 0}
.ef-store{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}
.ef-store div{background:var(--paper);border:1px solid var(--line);border-radius:var(--r);padding:14px;font-size:12.5px;color:var(--ink-m);min-width:0}
.ef-store b{display:block;font-size:13.5px;color:var(--ink);margin-bottom:4px}
.mech-fig{margin:0}
.mech-fig img{border-radius:var(--r);border:1px solid var(--line);margin:0 auto}
.mech-fig figcaption{font-size:12px;color:var(--ink-m);text-align:center;margin-top:10px}

/* 教学模型 · 四法四层 */
.methods{list-style:none;display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:26px}
.methods li{background:var(--paper);border:1px solid var(--line);border-radius:var(--r);padding:14px 16px;min-width:0}
.methods b{display:block;font-size:14px;color:var(--ink)}
.methods span{font-size:12.5px;color:var(--ink-m)}
.depths{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.depths span{border-radius:var(--r-pill);padding:8px 16px;font-size:13px;font-weight:600}
.depths span em{font-style:normal;font-weight:400;font-size:11.5px;margin-left:6px;opacity:.8}
.d1{background:#eef1f8;color:#3d63c4}
.d2{background:#e7f0ff;color:#2b5db8}
.d3{background:#e6f6ec;color:#1e7c43}
.d4{background:#fff3d6;color:#b07510}
.depths .arr{color:#b6bdcc;font-size:13px}
.depths-note{font-size:12px;color:var(--ink-m);margin-top:10px}

/* 交互模型 · 工具箱 */
.tools-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;margin-bottom:30px}
.tools-grid span{background:var(--paper);border:1px solid var(--line);border-radius:var(--r);
  padding:13px 14px;font-size:13.5px;font-weight:600;color:var(--ink);min-width:0}
.tools-grid em{display:block;font-style:normal;font-size:11px;font-weight:400;color:var(--ink-m);margin-top:2px}
.done-fig{max-width:430px;margin:0 auto}
.done-fig img{border-radius:var(--r);border:1px solid var(--line)}
.done-fig figcaption{font-size:12px;color:var(--ink-m);text-align:center;margin-top:10px}

/* ================= AI素养课（深色） ================= */
.ai-lit{background:
  radial-gradient(900px 480px at 80% 0,rgba(255,209,102,.08),transparent 60%),
  radial-gradient(900px 520px at 10% 100%,rgba(95,134,214,.14),transparent 60%),
  var(--space);
  padding:100px 0;text-align:center}
.ai-lit .sec-sub{margin:0 auto}
.levels{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin:48px 0 28px}
.level{background:rgba(14,20,38,.8);border:1px solid var(--line-dark);border-radius:var(--r-lg);
  padding:26px 20px;text-align:left;transition:border-color .15s,transform .15s}
.level:hover{border-color:var(--gold);transform:translateY(-3px)}
.level b{display:block;font-size:18px;color:var(--gold);margin-bottom:4px}
.level span{font-size:12px;color:var(--blue-bright)}
.level em{display:block;font-style:normal;font-size:12.5px;color:var(--txt-light-m);margin-top:12px;line-height:1.7}
.modules{display:flex;flex-wrap:wrap;justify-content:center;gap:10px;margin-bottom:36px}
.modules span{font-size:12.5px;color:var(--txt-light-m);border:1px solid var(--line-dark);
  border-radius:var(--r-pill);padding:7px 16px;background:rgba(255,255,255,.03)}
.free-badge{display:inline-block;font-size:15px;font-weight:700;color:#241a04;
  background:linear-gradient(135deg,var(--gold),var(--gold-deep));
  padding:12px 32px;border-radius:var(--r-pill);box-shadow:0 8px 28px rgba(240,169,46,.35)}

/* ================= 证据（浅色） ================= */
.proof{background:var(--paper);color:var(--ink);padding:96px 0;text-align:center}
.proof h2{color:var(--ink)}
.proof .hl{color:#b3730a}
.proof-stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin:46px 0 30px}
.stat{background:var(--card);border:1px solid var(--line);border-radius:var(--r-lg);padding:30px 18px;min-width:0}
.stat b{display:block;font-size:clamp(24px,3vw,34px);color:#2f54b0;font-weight:700;letter-spacing:.5px;margin-bottom:8px}
.stat:nth-child(4) b{color:#b3730a}
.stat span{font-size:12.5px;color:var(--ink-m);line-height:1.7}
.proof-note{font-size:13px;color:var(--ink-m);max-width:760px;margin:0 auto;
  background:var(--paper-alt);border-radius:var(--r);padding:16px 22px}

/* ================= 对号入座 ================= */
.check{background:var(--paper-alt);color:var(--ink);padding:96px 0}
.check h2{color:var(--ink)}
.check .hl{color:#b3730a}
.check-list{margin-top:42px;display:grid;grid-template-columns:1fr 1fr;gap:16px}
.check-card{background:var(--card);border:1px solid var(--line);border-radius:var(--r-lg);overflow:hidden}
.check-card summary{
  list-style:none;cursor:pointer;padding:22px 24px;
  font-size:15.5px;font-weight:600;color:var(--ink);
  display:flex;align-items:center;justify-content:space-between;gap:12px;
}
.check-card summary::-webkit-details-marker{display:none}
.open-i{flex:0 0 auto;width:26px;height:26px;border-radius:50%;border:1px solid #c3cad8;color:#7d8699;
  display:flex;align-items:center;justify-content:center;font-size:15px;font-weight:400;transition:.2s}
.check-card[open] .open-i{background:#2f54b0;border-color:#2f54b0;color:#fff;transform:rotate(45deg)}
.cc-body{padding:0 24px 22px}
.cc-body p{font-size:13.5px;color:#4a546c}
.cc-tags{margin-top:12px;font-size:12px;color:#2f54b0;font-weight:600}

/* ================= 适合/不适合 ================= */
.fit{background:var(--paper);color:var(--ink);padding:96px 0}
.fit-in{display:grid;grid-template-columns:1fr 1fr;gap:20px}
.fit-box{border-radius:var(--r-lg);padding:34px 34px 30px;border:1px solid var(--line)}
.fit-box h3{font-size:18px;margin-bottom:18px}
.fit-box ul{list-style:none}
.fit-box li{font-size:14px;color:#3a4258;padding:9px 0 9px 30px;position:relative}
.fit-yes{background:var(--card)}
.fit-yes h3{color:#1e7c43}
.fit-yes li::before{content:"✓";position:absolute;left:0;top:9px;color:#1e9c55;font-weight:700}
.fit-no{background:var(--paper-alt)}
.fit-no h3{color:#b04030}
.fit-no li::before{content:"–";position:absolute;left:2px;top:9px;color:#c06050;font-weight:700}

/* ================= 申请（深色） ================= */
.apply{background:
  radial-gradient(900px 500px at 15% 0,rgba(255,209,102,.08),transparent 60%),
  var(--space);
  padding:100px 0}
.apply-in{display:grid;grid-template-columns:minmax(0,.95fr) minmax(0,1.05fr);gap:56px;align-items:start}
.apply h2{font-size:clamp(24px,3vw,34px)}
.apply-copy p{color:var(--txt-light-m);font-size:14.5px;margin-top:10px}
.apply-points{list-style:none;margin-top:26px}
.apply-points li{font-size:13.5px;color:var(--txt-light-m);padding:9px 0 9px 26px;position:relative}
.apply-points li::before{content:"";position:absolute;left:0;top:17px;width:8px;height:8px;border-radius:50%;background:var(--gold)}

.apply-form{background:rgba(14,20,38,.85);border:1px solid var(--line-dark);
  border-radius:var(--r-lg);padding:34px;backdrop-filter:blur(8px)}
.field{margin-bottom:18px}
.field label{display:block;font-size:13px;color:var(--txt-light);font-weight:600;margin-bottom:8px}
.field input,.field select{
  width:100%;font-family:var(--sans);font-size:14px;color:var(--txt-light);
  background:rgba(5,7,15,.7);border:1px solid var(--line-dark);border-radius:var(--r);
  padding:13px 15px;outline:none;transition:border-color .15s;
}
.field input::placeholder{color:#66739a}
.field input:focus,.field select:focus{border-color:var(--gold)}
.field select{appearance:none;background-image:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='8'><path d='M1 1l5 5 5-5' stroke='%2397a3c2' stroke-width='1.6' fill='none'/></svg>");
  background-repeat:no-repeat;background-position:right 16px center;padding-right:40px}
.field select option{color:#141826}
.form-error{font-size:13px;color:#ff8a78;background:rgba(224,80,60,.12);border-radius:var(--r);
  padding:10px 14px;margin-bottom:14px}
.form-status{font-size:13px;color:var(--txt-light-m);background:rgba(120,160,220,.08);
  border:1px solid var(--line-dark);border-radius:var(--r);padding:14px;margin-top:14px;line-height:1.7}
.form-status b{color:var(--gold)}

/* 企业微信客服卡片（替代申请表单） */
.kefu-card{background:rgba(14,20,38,.85);border:1px solid var(--line-dark);
  border-radius:var(--r-lg);padding:34px;backdrop-filter:blur(8px);text-align:center}
.kefu-head{display:flex;align-items:center;gap:14px;margin-bottom:26px;text-align:left}
.kefu-logo{width:52px;height:52px;border-radius:14px;background:#fff;display:flex;
  align-items:center;justify-content:center;flex:none}
.kefu-logo svg{width:30px;height:30px}
.kefu-head b{display:block;font-size:16px;color:var(--txt-light)}
.kefu-head span{display:block;font-size:12px;color:var(--txt-light-m);margin-top:4px}
.kefu-btn{display:flex;align-items:center;justify-content:center;gap:9px}
.kefu-hint{font-size:12px;color:var(--txt-light-m);margin-top:14px;line-height:1.7}
.kefu-fine{font-size:11.5px;color:#66739a;margin-top:16px;padding-top:14px;border-top:1px solid var(--line-dark)}

/* ================= FAQ ================= */
.faq{background:var(--paper-alt);color:var(--ink);padding:96px 0}
.faq h2{color:var(--ink)}
.faq-list{margin-top:40px;display:flex;flex-direction:column;gap:12px;max-width:860px}
.faq-list details{background:var(--card);border:1px solid var(--line);border-radius:var(--r-lg)}
.faq-list summary{list-style:none;cursor:pointer;padding:20px 24px;font-size:15px;font-weight:600;color:var(--ink);
  display:flex;align-items:center;justify-content:space-between;gap:12px}
.faq-list summary::-webkit-details-marker{display:none}
.faq-list details[open] .open-i{background:#2f54b0;border-color:#2f54b0;color:#fff;transform:rotate(45deg)}
.faq-list .cc-body{padding:0 24px 22px}
.faq-list .cc-body p{font-size:14px;color:#4a546c}

/* ================= 页脚 ================= */
.footer{background:var(--space-2);border-top:1px solid var(--line-dark);padding-top:60px}
.footer-in{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:32px;padding-bottom:44px}
.f-brand{display:flex;flex-wrap:wrap;align-items:center;gap:10px;font-size:15px;font-weight:600}
.f-brand p{flex-basis:100%;font-size:12.5px;color:var(--txt-light-m);font-weight:400;margin-top:8px}
.f-col{display:flex;flex-direction:column;gap:10px}
.f-col b{font-size:13px;color:var(--txt-light);margin-bottom:4px}
.f-col a{font-size:13px;color:var(--txt-light-m)}
.f-col a:hover{color:var(--gold)}
.f-base{border-top:1px solid var(--line-dark);display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;
  padding:18px 24px;max-width:1180px;margin:0 auto;font-size:12px;color:#66739a}

/* ================= 入场动效 ================= */
.reveal{opacity:0;transform:translateY(20px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}

/* ============================================================
   响应式
   ============================================================ */
@media(max-width:1020px){
  .hero-in{grid-template-columns:minmax(0,1fr);gap:44px}
  .hero-copy,.hero-visual{min-width:0}
  .hero{padding-top:96px}
  .mech-split{grid-template-columns:minmax(0,1fr);gap:28px}
  .apply-in{grid-template-columns:minmax(0,1fr);gap:36px}
}

@media(max-width:860px){
  .nav-links{display:none}
  .hamburger{display:flex}
  .nav-act .btn{display:none}

  .pains{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr 1fr}
  .tools-grid{grid-template-columns:1fr 1fr}
  .levels{grid-template-columns:1fr 1fr}
  .proof-stats{grid-template-columns:1fr 1fr}
  .check-list{grid-template-columns:1fr}
  .fit-in{grid-template-columns:1fr}
  .footer-in{grid-template-columns:1fr 1fr}

  /* 架构图：移动端改为静态流 */
  .arch-diagram{height:auto;display:flex;flex-direction:column;align-items:center;gap:16px}
  .arch-core{position:static;transform:none;width:170px;height:170px;order:0}
  .arch-card{position:static;width:100%;max-width:420px}
  .arch-ring{display:contents}
  .arch-ring::before,.arch-ring::after{display:none}
  .flywheel{flex-direction:column;align-items:flex-start;gap:12px}
}

@media(max-width:560px){
  .wrap{padding:0 18px}
  .hero{padding:88px 18px 60px}
  .hero-visual iframe{height:380px}
  .hero-cta{flex-direction:column;align-items:stretch}
  .hero-cta .btn{width:100%}
  .steps,.tools-grid,.levels,.proof-stats,.methods,.ef-store,.footer-in{grid-template-columns:1fr}
  .chain-vis{flex-direction:column;gap:16px}
  .chain-line{width:2px;height:56px;background:repeating-linear-gradient(180deg,var(--gold) 0 8px,transparent 8px 16px)}
  .chain-line span{right:50%;top:auto;bottom:-2px;transform:translateX(50%);
    border-left:6px solid transparent;border-right:6px solid transparent;border-top:9px solid var(--gold);border-bottom:none}
  .mech{padding:22px 18px}
  .apply-form,.kefu-card{padding:24px 20px}
  .depths .arr{display:none}
  .scroll-hint{font-size:11.5px;width:calc(100% - 36px);text-align:center}
  .f-base{justify-content:center;text-align:center}
}

@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal{opacity:1;transform:none;transition:none}
}