/* ============================================================
   萤火学术 — 视觉样式 v2（移动优先）
   ============================================================ */
:root{
  --navy:#1b2a4a;
  --navy-2:#243a63;
  --blue:#2f6bff;
  --blue-d:#1f4fd8;
  --gold:#e8a33d;
  --ink:#1b2233;
  --gray:#5b667a;
  --gray-2:#8b95a7;
  --line:#e4e8f0;
  --bg:#ffffff;
  --bg-alt:#f5f7fb;
  --radius:14px;
  --radius-lg:20px;
  --shadow:0 6px 24px rgba(27,42,74,.08);
  --shadow-lg:0 18px 48px rgba(27,42,74,.14);
  --max:1200px;
  --nav-h:64px;
  --font:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;font-family:var(--font);color:var(--ink);background:var(--bg);
  font-size:15px;line-height:1.75;-webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
img{max-width:100%;height:auto;display:block}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
ul{padding-left:1.1em;margin:.6em 0}
h1,h2,h3,h4{margin:0;line-height:1.3;font-weight:800;letter-spacing:-.2px}
p{margin:.6em 0}
.container{width:100%;max-width:var(--max);margin:0 auto;padding:0 20px}

/* 滚动进度 */
.scroll-progress{
  position:fixed;top:0;left:0;height:3px;width:0;z-index:200;
  background:linear-gradient(90deg,var(--blue),var(--gold));
  transition:width .1s linear;
}

/* 公告条 */
.notice{
  position:relative;z-index:60;background:linear-gradient(90deg,var(--navy),var(--navy-2));
  color:#dbe5ff;font-size:13px;text-align:center;padding:7px 16px;
  display:flex;align-items:center;justify-content:center;gap:8px;
}
.notice span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;max-width:100%}
.notice b{color:var(--gold)}

/* 导航 */
.nav{
  position:sticky;top:0;z-index:100;background:rgba(255,255,255,.94);
  backdrop-filter:saturate(180%) blur(12px);border-bottom:1px solid var(--line);
  transition:box-shadow .25s;
}
.nav.scrolled{box-shadow:0 6px 22px rgba(27,42,74,.09)}
.nav-inner{
  max-width:var(--max);margin:0 auto;padding:0 20px;height:var(--nav-h);
  display:flex;align-items:center;justify-content:space-between;gap:16px;
}
.logo{display:flex;align-items:center;gap:10px;font-weight:900;font-size:17px;letter-spacing:.5px}
.logo-mark{
  width:36px;height:36px;flex:0 0 36px;border-radius:11px;display:grid;place-items:center;
  background:linear-gradient(135deg,var(--navy),var(--blue));color:#fff;font-size:18px;
  box-shadow:0 6px 16px rgba(47,107,255,.28);
}
.logo small{display:block;font-size:10px;color:var(--gray-2);font-weight:600;letter-spacing:1.4px}
.menu{display:flex;align-items:center;gap:4px}
.menu a{
  padding:8px 12px;border-radius:9px;font-size:14px;font-weight:600;color:var(--gray);
  transition:.2s;white-space:nowrap;
}
.menu a:hover{color:var(--blue);background:#f0f5ff}
.nav-cta{display:flex;align-items:center;gap:10px}
.burger{
  display:none;width:42px;height:42px;border-radius:11px;border:1px solid var(--line);
  place-items:center;background:#fff;
}
.burger span{display:block;width:18px;height:2px;background:var(--ink);border-radius:2px;position:relative}
.burger span::before,.burger span::after{
  content:'';position:absolute;left:0;width:18px;height:2px;background:var(--ink);border-radius:2px;transition:.25s;
}
.burger span::before{top:-6px}.burger span::after{top:6px}
.burger[aria-expanded="true"] span{background:transparent}
.burger[aria-expanded="true"] span::before{top:0;transform:rotate(45deg)}
.burger[aria-expanded="true"] span::after{top:0;transform:rotate(-45deg)}

/* 按钮 */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:7px;
  padding:12px 22px;border-radius:12px;font-size:15px;font-weight:700;
  transition:.24s;white-space:nowrap;border:1px solid transparent;
}
.btn-primary{background:linear-gradient(135deg,var(--blue),var(--blue-d));color:#fff;box-shadow:0 10px 24px rgba(47,107,255,.28)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 14px 30px rgba(47,107,255,.36)}
.btn-ghost{background:#fff;border-color:var(--line);color:var(--ink)}
.btn-ghost:hover{border-color:var(--blue);color:var(--blue)}
.btn-gold{background:linear-gradient(135deg,#f0b959,var(--gold));color:#3a2600;box-shadow:0 10px 24px rgba(232,163,61,.3)}
.btn-sm{padding:9px 16px;font-size:13.5px;border-radius:10px}
.btn-block{width:100%}

/* 通用区块 */
.section{padding:72px 0}
.section-alt{background:var(--bg-alt)}
.section-head{text-align:center;max-width:660px;margin:0 auto 42px}
.section-head h2{font-size:30px;margin-bottom:10px}
.section-head p{color:var(--gray);font-size:15px;margin:0}
.eyebrow{
  display:inline-block;font-size:11.5px;font-weight:800;letter-spacing:2px;color:var(--blue);
  background:#eaf1ff;padding:5px 14px;border-radius:999px;margin-bottom:14px;
}

/* Hero */
.hero{
  position:relative;padding:66px 0 78px;overflow:hidden;
  background:linear-gradient(160deg,#f7faff 0%,#eef4ff 45%,#ffffff 100%);
}
.hero::before,.hero::after{
  content:'';position:absolute;border-radius:50%;filter:blur(70px);opacity:.55;z-index:0;
}
.hero::before{width:420px;height:420px;background:rgba(47,107,255,.28);top:-160px;right:-120px}
.hero::after{width:340px;height:340px;background:rgba(232,163,61,.24);bottom:-160px;left:-120px}
.hero-grid{position:relative;z-index:1;display:grid;grid-template-columns:1.15fr .85fr;gap:48px;align-items:center}
.hero h1{font-size:44px;line-height:1.22;margin-bottom:18px}
.hero h1 em{
  font-style:normal;
  background:linear-gradient(120deg,var(--blue),#7aa6ff);-webkit-background-clip:text;background-clip:text;color:transparent;
}
.hero-sub{font-size:16.5px;color:var(--gray);max-width:560px}
.hero-tags{display:flex;flex-wrap:wrap;gap:8px;margin:22px 0 26px}
.hero-tags span{
  font-size:13px;font-weight:600;color:var(--navy-2);background:#fff;border:1px solid var(--line);
  padding:6px 13px;border-radius:999px;box-shadow:0 2px 8px rgba(27,42,74,.05);
}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px}
.hero-trust{display:flex;flex-wrap:wrap;gap:20px;margin-top:28px;color:var(--gray);font-size:13.5px}
.hero-trust b{color:var(--ink);font-size:17px;display:block;line-height:1.2}

/* 核心保障条 */
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.stat{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:20px 18px;text-align:center;box-shadow:var(--shadow);transition:.22s;
}
.stat:hover{transform:translateY(-3px);border-color:#c9dbff}
.stat b{display:block;font-size:18px;font-weight:800;color:var(--navy);margin-bottom:4px}
.stat span{font-size:13px;color:var(--gray)}

/* 卡片网格 */
.grid{display:grid;gap:20px}
.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:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);
  padding:26px 24px;transition:.26s;display:flex;flex-direction:column;
}
.card:hover{transform:translateY(-5px);box-shadow:var(--shadow-lg);border-color:#d3dffb}
.card-icon{
  width:48px;height:48px;border-radius:12px;display:grid;place-items:center;
  background:#f0f5ff;color:var(--blue);margin-bottom:16px;transition:.24s;
}
.card:hover .card-icon{
  background:var(--blue);color:#fff;
}
.card-icon svg{display:block}
.contact-list i svg{display:block}
.ui-ic{vertical-align:-2px;margin-right:2px}
.card h3{font-size:18px;margin-bottom:8px}
.card p{font-size:14px;color:var(--gray);margin:0 0 14px}
.card ul{font-size:13.5px;color:var(--gray);margin:0 0 16px;padding-left:1.05em}
.card li{margin:4px 0}
.card-foot{
  margin-top:auto;display:flex;align-items:center;justify-content:space-between;
  padding-top:14px;border-top:1px dashed var(--line);
}
.price{font-size:16px;font-weight:900;color:#e0483c}
.price small{font-weight:600;color:var(--gray-2);font-size:12px}
.card-link{font-size:13.5px;font-weight:700;color:var(--blue)}
.card-link:hover{text-decoration:underline}

/* 平台卡 */
.plat{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:20px;text-align:center;transition:.24s;
}
.plat:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);border-color:#d3dffb}
.plat i{
  font-style:normal;font-size:22px;display:grid;place-items:center;width:46px;height:46px;
  margin:0 auto 10px;border-radius:13px;background:#f0f5ff;color:var(--blue);
}
.plat b{display:block;font-size:15px;margin-bottom:2px}
.plat span{font-size:12.5px;color:var(--gray-2)}

/* 流程 */
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;counter-reset:s}
.step{
  position:relative;background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:24px 20px 20px;
}
.step::before{
  counter-increment:s;content:counter(s,decimal-leading-zero);
  font-size:12px;font-weight:900;letter-spacing:1px;color:var(--blue);
  background:#eaf1ff;padding:4px 10px;border-radius:999px;display:inline-block;margin-bottom:12px;
}
.step h3{font-size:16.5px;margin-bottom:6px}
.step p{font-size:13.5px;color:var(--gray);margin:0}

/* 表格 */
.table-wrap{overflow-x:auto;border-radius:var(--radius);border:1px solid var(--line);background:#fff}
table{width:100%;border-collapse:collapse;font-size:14px;min-width:560px}
th,td{padding:13px 16px;text-align:left;border-bottom:1px solid var(--line)}
th{background:#f6f8fc;font-weight:800;font-size:13.5px;color:var(--navy);white-space:nowrap}
tbody tr:last-child td{border-bottom:none}
tbody tr:hover{background:#fafbff}
td b{color:#e0483c}

/* 案例 */
.case{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:22px;display:flex;flex-direction:column;gap:10px;
}
.case-top{display:flex;align-items:center;justify-content:space-between;gap:10px}
.case-tag{font-size:12px;font-weight:700;color:var(--blue);background:#eaf1ff;padding:4px 11px;border-radius:999px}
.case-date{font-size:12px;color:var(--gray-2)}
.case h3{font-size:16px}
.case p{font-size:13.5px;color:var(--gray);margin:0}
.case-meta{display:flex;gap:14px;flex-wrap:wrap;font-size:12.5px;color:var(--gray-2);margin-top:auto;padding-top:12px;border-top:1px dashed var(--line)}
.case-meta b{color:var(--ink)}

/* FAQ */
.faq{max-width:820px;margin:0 auto}
.faq-item{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  margin-bottom:12px;overflow:hidden;transition:.24s;
}
.faq-item.open{border-color:#c9dbff;box-shadow:var(--shadow)}
.faq-q{
  width:100%;text-align:left;padding:17px 20px;font-size:15px;font-weight:700;
  display:flex;align-items:center;justify-content:space-between;gap:14px;
}
.faq-q::after{content:'+';font-size:20px;color:var(--blue);font-weight:400;transition:.25s;flex:0 0 auto}
.faq-item.open .faq-q::after{transform:rotate(45deg)}
.faq-a{max-height:0;overflow:hidden;transition:max-height .32s ease;padding:0 20px;color:var(--gray);font-size:14px}
.faq-item.open .faq-a{max-height:420px;padding-bottom:18px}

/* 报价计算器 */
.calc{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);
  box-shadow:var(--shadow-lg);overflow:hidden;
}
.calc-tabs{
  display:flex;gap:6px;padding:12px 12px 0;overflow-x:auto;
  scrollbar-width:none;background:#f8faff;border-bottom:1px solid var(--line);
}
.calc-tabs::-webkit-scrollbar{display:none}
.calc-tab{
  padding:11px 16px;border-radius:11px 11px 0 0;font-size:14px;font-weight:700;color:var(--gray);
  white-space:nowrap;border-bottom:2px solid transparent;
}
.calc-tab:hover{color:var(--blue)}
.calc-tab.active{color:var(--blue);background:#fff;border-bottom-color:var(--blue)}
.calc-body{display:grid;grid-template-columns:1.25fr .75fr;gap:0}
.calc-main{padding:26px 26px 24px}
.calc-f-row{display:grid;grid-template-columns:110px 1fr;gap:12px;align-items:center;margin-bottom:13px}
.calc-f-row label{font-size:13.5px;font-weight:700;color:var(--gray)}
.calc-f-row select{
  width:100%;padding:11px 13px;border:1px solid var(--line);border-radius:11px;
  font-size:14px;font-family:inherit;background:#fbfcfe;
}
.calc-f-row select:focus{outline:none;border-color:var(--blue);box-shadow:0 0 0 4px rgba(47,107,255,.12)}
.calc-checks{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:18px 0 10px}
.calc-checks label{
  display:flex;align-items:center;gap:8px;font-size:13.5px;color:var(--ink);
  background:#f8faff;border:1px solid var(--line);border-radius:10px;padding:9px 12px;cursor:pointer;transition:.2s;
}
.calc-checks label:hover{border-color:#c9dbff}
.calc-checks input{width:16px;height:16px;accent-color:var(--blue);flex:0 0 auto}
.calc-checks em{font-style:normal;color:var(--gray-2);font-size:12px;margin-left:auto}
.calc-hint{font-size:12.5px;color:var(--gray-2);margin:12px 0 0}
.calc-side{
  background:linear-gradient(165deg,var(--navy),var(--navy-2));color:#fff;
  padding:28px 24px;display:flex;flex-direction:column;
}
.calc-side h3{font-size:15px;color:#a9c1f0;font-weight:700;letter-spacing:.5px}
.calc-out .out-total{font-size:40px;font-weight:900;letter-spacing:-1px;margin:8px 0 2px;line-height:1.1}
.calc-out .out-range{font-size:13.5px;color:#b9c9e8}
.calc-out .out-range b{color:#fff}
.calc-out .out-list{margin:18px 0 0;font-size:13px;color:#cddaf3;flex:1;list-style:none;padding:0}
.calc-out .out-list li{
  display:flex;justify-content:space-between;gap:10px;padding:6px 0;
  border-bottom:1px dashed rgba(255,255,255,.13);
}
.calc-out .out-list li span:last-child{color:#fff;font-weight:700;white-space:nowrap}
.calc-out .out-list li.muted{color:#96aad1;font-size:12.5px;border:0;padding:2px 0}
.calc-out .out-note{font-size:12px;color:#96aad1;margin-top:14px}
.calc-preview-box{
  background:rgba(0,0,0,.22);border:1px solid rgba(255,255,255,.14);border-radius:12px;
  padding:14px;margin:12px 0 16px;max-height:260px;overflow-y:auto;
}
.order-preview-text{
  font-family:inherit;font-size:12.5px;line-height:1.75;color:#e1ebfd;white-space:pre-wrap;
  word-break:break-all;margin:0;
}
.calc-side-actions{display:flex;flex-direction:column;gap:8px}
.price-hint{font-size:13.5px;font-weight:700;color:var(--blue);background:#eaf1ff;padding:4px 10px;border-radius:6px}
.calc-actions{display:flex;gap:10px;margin-top:20px;flex-wrap:wrap}
.calc-actions .btn{flex:1 1 140px}
.calc-f-note{grid-column:2;font-size:12px;color:var(--gray-2);margin:-6px 0 12px}
.calc-f-row input[type=number]{
  width:100%;padding:11px 13px;border:1px solid var(--line);border-radius:11px;font-size:14px;font-family:inherit;background:#fbfcfe;
}

/* CTA */
.cta-band{
  background:linear-gradient(150deg,var(--navy),#2d4a80);color:#fff;border-radius:var(--radius-lg);
  padding:44px 36px;display:flex;align-items:center;justify-content:space-between;gap:28px;flex-wrap:wrap;
  box-shadow:var(--shadow-lg);
}
.cta-band h2{font-size:26px;margin-bottom:8px}
.cta-band p{color:#c2d2ef;margin:0;font-size:14.5px}
.cta-band .btn{flex:0 0 auto}

/* Hero 居中纯展示布局 */
.hero-center{display:flex;justify-content:center;text-align:center}
.hero-content{max-width:820px;margin:0 auto;display:flex;flex-direction:column;align-items:center}
.hero-content .hero-sub{margin:0 auto}
.hero-content .hero-tags{justify-content:center}
.hero-content .hero-actions{justify-content:center}
.hero-content .hero-trust{justify-content:center}

/* 联系 */
.contact-single{max-width:680px;margin:0 auto}
.contact-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);padding:32px 30px;box-shadow:var(--shadow-lg)}
.contact-list{list-style:none;padding:0;margin:0}
.contact-list li{
  display:flex;align-items:center;gap:13px;padding:13px 0;border-bottom:1px dashed var(--line);font-size:14.5px;
}
.contact-list li:last-child{border-bottom:none}
.contact-list i{
  font-style:normal;width:38px;height:38px;flex:0 0 38px;border-radius:11px;display:grid;place-items:center;
  background:#eaf1ff;font-size:18px;
}
.contact-list b{display:block;font-size:12px;color:var(--gray-2);font-weight:600}
.contact-list .val{font-weight:800;color:var(--navy)}
.wx-chip{
  font-size:12.5px;font-weight:700;color:var(--blue);background:#eaf1ff;border-radius:999px;
  padding:3px 10px;margin-left:6px;
}
.promise{margin-top:20px;background:#f8faff;border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px}
.promise b{font-size:14px;display:block;margin-bottom:8px}
.promise ul{margin:0;padding-left:1.1em;font-size:13.5px;color:var(--gray)}
.promise li{margin:5px 0}

/* 页脚 */
.footer{background:#101a2e;color:#8fa2c4;padding:52px 0 26px;font-size:13.5px}
.footer-inner{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:34px}
.footer h4{color:#fff;font-size:15px;margin-bottom:14px}
.footer .logo{color:#fff;margin-bottom:12px}
.footer .logo small{color:#6a7fa3}
.footer ul{list-style:none;padding:0;margin:0}
.footer li{margin:8px 0}
.footer a:hover{color:#fff}
.footer-bottom{
  margin-top:34px;padding-top:20px;border-top:1px solid rgba(255,255,255,.09);
  display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap;font-size:12.5px;color:#66799c;
}

/* 悬浮按钮 */
.float-order{
  position:fixed;right:18px;bottom:18px;z-index:150;
  display:flex;flex-direction:column;gap:10px;align-items:flex-end;
}
.float-order button,.float-order a{
  display:inline-flex;align-items:center;gap:6px;padding:12px 18px;border-radius:999px;
  font-size:14px;font-weight:700;color:#fff;box-shadow:0 10px 24px rgba(27,42,74,.22);
  background:linear-gradient(135deg,#1f6bf5,#174db8);transition:.24s;
}
.float-order button{
  background:linear-gradient(135deg,#0fa35b,#0c8449);
}
.float-order svg{display:block;flex:0 0 auto}
.float-order button:hover,.float-order a:hover{transform:translateY(-3px)}
.to-top{
  position:fixed;left:18px;bottom:22px;z-index:150;width:44px;height:44px;border-radius:14px;
  display:grid;place-items:center;background:#fff;border:1px solid var(--line);color:var(--navy);
  font-size:18px;font-weight:800;box-shadow:var(--shadow);opacity:0;pointer-events:none;transition:.26s;
}
.to-top.show{opacity:1;pointer-events:auto}
.to-top:hover{border-color:var(--blue);color:var(--blue)}

/* 弹层 */
.modal{
  position:fixed;inset:0;z-index:300;display:grid;place-items:center;padding:20px;
  background:rgba(16,26,46,.55);backdrop-filter:blur(4px);
  opacity:0;pointer-events:none;transition:.25s;
}
.modal.open{opacity:1;pointer-events:auto}
.modal-box{
  background:#fff;border-radius:var(--radius-lg);width:100%;max-width:420px;
  padding:30px 26px 26px;text-align:center;position:relative;
  transform:translateY(14px) scale(.98);transition:.28s;box-shadow:var(--shadow-lg);
}
.modal.open .modal-box{transform:none}
.modal-close{
  position:absolute;top:12px;right:12px;width:34px;height:34px;border-radius:10px;
  display:grid;place-items:center;font-size:20px;color:var(--gray-2);
}
.modal-close:hover{background:#f3f6fb;color:var(--ink)}
.modal-box h3{font-size:20px;margin-bottom:6px}
.modal-box>p{font-size:13.5px;color:var(--gray);margin:0 0 18px}
#wxQR{
  width:190px;height:190px;margin:0 auto 14px;border-radius:var(--radius);overflow:hidden;
  border:1px dashed var(--line);display:grid;place-items:center;background:#fafcff;
}
#wxQR img{width:100%;height:100%;object-fit:contain}
.qr-fallback{font-size:12px;color:var(--gray-2);padding:14px;line-height:1.8}
.qr-fallback b{color:var(--blue);word-break:break-all}
.qr-fallback span{display:block;margin-top:8px;font-size:14px;font-weight:800;color:var(--navy)}
.wx-line{font-size:15px;margin:0 0 6px}
.wx-line b{color:var(--navy);font-size:17px;letter-spacing:.4px}
#wxAlias{display:flex;flex-wrap:wrap;gap:6px;justify-content:center;margin:10px 0 16px;font-size:12.5px;color:var(--gray-2)}
.modal-tip{font-size:12.5px;color:var(--gray-2);margin:14px 0 0}

/* Toast */
.toast{
  position:fixed;left:50%;bottom:96px;transform:translate(-50%,18px);z-index:400;
  background:rgba(16,26,46,.94);color:#fff;font-size:14px;font-weight:600;
  padding:12px 22px;border-radius:999px;opacity:0;pointer-events:none;transition:.28s;
  max-width:calc(100vw - 40px);text-align:center;
}
.toast.show{opacity:1;transform:translate(-50%,0)}

/* 渐显 */
.reveal{opacity:0;transform:translateY(18px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width:1080px){
  .hero-grid{grid-template-columns:1fr;gap:34px}
  .hero h1{font-size:36px}
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:repeat(2,1fr)}
  .calc-body{grid-template-columns:1fr}
  .contact-grid{grid-template-columns:1fr;gap:24px}
  .footer-inner{grid-template-columns:1fr 1fr;gap:26px}
}
@media (max-width:820px){
  .nav-cta .btn{display:none}
  .burger{display:grid}
  .menu{
    position:absolute;top:100%;left:0;right:0;display:flex;flex-direction:column;
    background:#fff;align-items:stretch;gap:0;
    padding:8px 16px 20px;border-bottom:1px solid var(--line);
    box-shadow:0 16px 34px rgba(27,42,74,.14);
    transform:translateY(-130%);opacity:0;pointer-events:none;transition:.32s ease;
    max-height:calc(100vh - 60px);overflow-y:auto;z-index:99;
  }
  .menu.open{transform:translateY(0);opacity:1;pointer-events:auto}
  .menu a{padding:13px 12px;border-radius:10px;font-size:15px;border-bottom:1px solid #f1f4f9}
  .section{padding:54px 0}
  .section-head h2{font-size:25px}
  .grid-3,.grid-2{grid-template-columns:1fr}
  .stats{grid-template-columns:repeat(2,1fr);gap:12px}
  .stat b{font-size:25px}
  .hero h1{font-size:30px}
  .cta-band{padding:32px 24px}
  .cta-band h2{font-size:22px}
  .calc-checks{grid-template-columns:1fr}
  .calc-tabs{padding:10px 10px 0}
  .footer-inner{grid-template-columns:1fr}
}
@media (max-width:480px){
  .container{padding:0 15px}
  .hero{padding:44px 0 56px}
  .hero h1{font-size:26px}
  .hero-sub{font-size:15px}
  .card{padding:22px 18px}
  .calc-main{padding:20px 18px}
  .calc-side{padding:24px 20px}
  .contact-card{padding:22px 18px}
  .float-order{right:12px;bottom:12px}
  .float-order button,.float-order a{padding:11px 16px;font-size:13.5px}
  .to-top{left:12px;bottom:14px;width:40px;height:40px}
  .footer-bottom{flex-direction:column;gap:6px}
}
@media (max-width:360px){
  .hero h1{font-size:23px}
  .stats{grid-template-columns:1fr 1fr;gap:10px}
}

/* 打印：方便客户直接存 PDF 当需求单 */
@media print{
  .nav,.float-order,.to-top,.modal,.notice,.scroll-progress{display:none !important}
  body{font-size:12px}
  .calc-side{background:#f2f5fb;color:#1b2233}
  .calc-side h3{color:#1b2233}
  .order-preview-text{color:#1b2233}
  .section{padding:18px 0;break-inside:avoid}
}