/* Manwa - usdtqbgfwz.cn | v20261014 */
:root{
  --ink:#1f2a17;
  --ink-2:#4a5a3e;
  --ink-mist:#7d8a72;
  --green:#7CB342;
  --green-deep:#2E7D32;
  --green-dark:#1B5E20;
  --green-bright:#9CCC65;
  --green-pale:#F1F8E9;
  --green-mist:#F8FCEF;
  --orange:#FF7043;
  --orange-deep:#E45A2E;
  --orange-pale:#FFE8DF;
  --white:#ffffff;
  --line:#DCE8C8;
  --shadow-book:0 16px 36px rgba(31,42,23,.22);
  --shadow-soft:0 8px 20px rgba(31,42,23,.10);
  --shadow-cta:0 6px 18px rgba(46,125,50,.35);
  --radius-lg:22px;
  --radius-md:14px;
  --radius-sm:9px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:"PingFang SC","Microsoft YaHei","Noto Sans SC",sans-serif;
  color:var(--ink);
  background:var(--white);
  line-height:1.78;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
ul,ol{list-style:none}
[id]{scroll-margin-top:84px}
.wrap{width:min(1180px,92%);margin:0 auto}

/* ---------- 入场动画 ---------- */
.rv{opacity:0;transform:translateY(28px);transition:opacity .7s ease,transform .7s ease}
.rv.on{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .rv{opacity:1;transform:none;transition:none}
  *{animation:none!important;transition:none!important}
}

/* ---------- 顶栏 ---------- */
.site-header{
  position:sticky;top:0;z-index:60;
  background:rgba(255,255,255,.95);
  backdrop-filter:blur(10px);
  border-bottom:3px solid var(--green-deep);
}
.header-inner{display:flex;align-items:center;gap:26px;height:70px}
.brand{display:flex;align-items:center;gap:10px;flex-shrink:0}
.brand img{width:42px;height:42px;border-radius:11px;border:2px solid var(--green-deep)}
.brand-name{font-size:19px;font-weight:900;letter-spacing:1px;color:var(--green-deep)}
.primary-nav{display:flex;gap:4px;margin-left:auto}
.primary-nav a{
  font-size:14.5px;font-weight:600;color:var(--ink-2);padding:8px 14px;border-radius:999px;
  transition:color .2s,background .2s;
}
.primary-nav a:hover{color:var(--green-deep);background:var(--green-pale)}
.header-cta{
  flex-shrink:0;background:var(--green-deep);color:#fff;font-size:14px;font-weight:700;
  padding:9px 22px;border-radius:999px;transition:background .2s,transform .15s;
  box-shadow:0 3px 0 var(--green-dark);
}
.header-cta:hover{background:var(--green);transform:translateY(1px)}
.menu-toggle{
  display:none;margin-left:auto;width:42px;height:42px;border:2px solid var(--green-deep);
  border-radius:10px;background:var(--green-pale);cursor:pointer;flex-direction:column;
  align-items:center;justify-content:center;gap:5px;
}
.menu-toggle span{display:block;width:18px;height:2.5px;background:var(--green-deep);border-radius:2px}

/* ---------- 英雄区：立体书架 + 翻开的书 ---------- */
.hero{position:relative;background:linear-gradient(180deg,var(--green-mist) 0%,#fff 100%);overflow:hidden}
.hero-bg{
  position:absolute;top:-120px;right:-80px;width:480px;height:480px;border-radius:50%;
  background:radial-gradient(circle,rgba(124,179,66,.18),transparent 65%);
}
.hero-grid{
  position:relative;display:grid;grid-template-columns:1.02fr .98fr;gap:44px;
  align-items:center;padding:66px 0 78px;
}
.eyebrow{
  display:inline-flex;align-items:center;gap:8px;font-size:13.5px;font-weight:700;
  color:var(--green-deep);background:#fff;border:2px solid var(--green-deep);
  padding:6px 16px;border-radius:999px;margin-bottom:20px;
}
.eyebrow i{width:9px;height:9px;border-radius:50%;background:var(--orange)}
.hero h1{font-size:clamp(42px,5.4vw,62px);line-height:1.12;letter-spacing:2px;color:var(--ink)}
.hero-lead{margin-top:20px;font-size:16.5px;color:var(--ink-2);max-width:540px}
.hero-tags{display:flex;flex-wrap:wrap;gap:10px;margin-top:24px}
.hero-tags span{font-size:13.5px;font-weight:700;padding:7px 17px;border-radius:999px;border:1.5px solid var(--green-deep)}
.tag-a{background:var(--green-pale);color:var(--green-deep)}
.tag-b{background:var(--orange-pale);color:var(--orange-deep);border-color:var(--orange-deep)}
.tag-c{background:#fff;color:var(--ink)}
.hero-action{display:flex;align-items:center;gap:18px;margin-top:32px}
.primary-button{
  display:inline-flex;align-items:center;gap:10px;
  background:linear-gradient(145deg,var(--green) 0%,var(--green-deep) 100%);
  color:#fff;font-size:17px;font-weight:800;padding:15px 42px;border-radius:999px;
  box-shadow:var(--shadow-cta);transition:transform .2s,box-shadow .2s;
}
.primary-button:hover{transform:translateY(-2px)}
.primary-button svg{width:18px;height:18px}
.hero-note{font-size:12.5px;color:var(--ink-mist)}
.hero-stat{
  display:flex;margin-top:32px;border:1.5px solid var(--green-deep);border-radius:var(--radius-md);
  overflow:hidden;background:#fff;width:fit-content;
}
.hero-stat li{padding:12px 26px;border-left:1.5px solid var(--line);background:var(--green-mist)}
.hero-stat li:first-child{border-left:0;background:var(--green-pale)}
.hero-stat b{display:block;font-size:21px;font-weight:900;color:var(--green-deep)}
.hero-stat b i{font-style:normal;font-size:14px;color:var(--orange);margin-left:2px}
.hero-stat span{font-size:12px;color:var(--ink-mist)}

/* 书架舞台 */
.shelf-stage{position:relative;min-height:560px;padding:20px 10px 30px}
.shelf{
  position:relative;z-index:1;display:flex;flex-direction:column;gap:0;
  max-width:440px;margin:0 auto;
}
.shelf-row{
  display:flex;justify-content:center;align-items:flex-end;gap:5px;
  padding:0 14px;height:118px;
}
.book-spine{
  width:34px;border-radius:4px 4px 2px 2px;border:1.5px solid var(--ink);
  display:flex;align-items:center;justify-content:center;
  writing-mode:vertical-rl;text-orientation:upright;
  font-size:9px;font-weight:800;letter-spacing:1px;color:#fff;
  box-shadow:inset 0 0 0 2px rgba(255,255,255,.18);position:relative;
}
.book-spine span{padding:8px 0;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-height:96px}
.bs1{height:112px;background:linear-gradient(180deg,var(--green-bright),var(--green-deep))}
.bs2{height:96px;background:linear-gradient(180deg,var(--orange),var(--orange-deep))}
.bs3{height:108px;background:linear-gradient(180deg,#9CCC65,#1B5E20)}
.bs4{height:100px;background:linear-gradient(180deg,#E0E0E0,#616161)}
.bs5{height:92px;background:linear-gradient(180deg,#C5E1A5,#558B2F)}
.bs6{height:104px;background:linear-gradient(180deg,var(--green),var(--green-dark))}
.shelf-board{
  height:14px;background:linear-gradient(180deg,var(--green-bright) 0%,var(--green-deep) 60%,var(--green-dark) 100%);
  border-radius:3px;border:1.5px solid var(--ink);
  box-shadow:0 4px 8px rgba(31,42,23,.18);position:relative;
}
.shelf-board::after{
  content:"";position:absolute;left:6px;right:6px;top:3px;height:2px;border-radius:2px;
  background:rgba(255,255,255,.35);
}
/* 漫蛙吉祥物蹲架顶 */
.mascot{
  position:absolute;z-index:4;top:4px;right:24px;
  width:58px;height:58px;border-radius:50%;background:#fff;
  border:2px solid var(--green-deep);display:flex;align-items:center;justify-content:center;
  box-shadow:var(--shadow-soft);animation:bob 4.5s ease-in-out infinite;
}
.mascot img{width:42px;height:42px;border-radius:50%}
@keyframes bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-6px)}}
/* 翻开的书 */
.open-book{
  position:absolute;z-index:3;left:50%;top:50%;transform:translate(-50%,-46%) rotate(-2deg);
  display:flex;background:#fff;border:2px solid var(--ink);border-radius:6px;
  box-shadow:var(--shadow-book);width:230px;
}
.ob-page{flex:1;padding:12px 14px;min-width:0}
.ob-left{border-right:2px solid var(--ink);position:relative}
.ob-left::after{
  content:"";position:absolute;right:-7px;top:0;bottom:0;width:12px;
  background:linear-gradient(90deg,rgba(0,0,0,.18),transparent);
}
.ob-page b{font-size:9.5px;font-weight:900;color:var(--orange-deep);letter-spacing:.5px}
.ob-page p{font-size:9px;color:var(--ink-2);margin:2px 0 8px;font-weight:600}
.ob-art{height:54px;border-radius:5px;border:1.5px solid var(--ink)}
.ob-art.oa1{background:linear-gradient(135deg,#C5E1A5 0%,var(--green) 55%,var(--green-dark) 100%)}
.ob-art.oa2{background:linear-gradient(135deg,#FFE0B2 0%,var(--orange) 55%,var(--orange-deep) 100%);margin-top:8px}
.ob-lines{display:flex;flex-direction:column;gap:4px;margin-top:8px}
.ob-lines i{height:3px;border-radius:2px;background:var(--line)}
.ob-lines i:nth-child(1){width:80%}
.ob-lines i:nth-child(2){width:64%}
.ob-lines i:nth-child(3){width:72%}
.ob-progress{display:flex;align-items:center;gap:6px;margin-top:8px}
.ob-progress i{font-style:normal;font-size:9px;font-weight:800;color:var(--green-deep)}
.ob-progress b{flex:1;height:6px;border-radius:99px;background:var(--green-pale);border:1px solid var(--line);overflow:hidden}
.ob-progress b::after{content:"";display:block;width:86%;height:100%;background:linear-gradient(90deg,var(--green),var(--green-deep))}
.ob-nav{display:flex;gap:6px;margin-top:8px}
.ob-nav span{flex:1;text-align:center;font-size:8.5px;font-weight:700;color:var(--ink-mist);padding:4px 0;border:1px solid var(--line);border-radius:5px}
.ob-nav span.on{color:#fff;background:var(--green-deep);border-color:var(--green-deep)}
/* 浮动标签 */
.float-tag{
  position:absolute;z-index:5;background:#fff;border:2px solid var(--ink);
  border-radius:10px;padding:7px 13px;display:flex;flex-direction:column;align-items:center;
  box-shadow:var(--shadow-soft);
}
.float-tag b{font-size:11px;font-weight:900;color:var(--green-deep);line-height:1.2}
.float-tag span{font-size:9.5px;color:var(--ink-mist);font-weight:600}
.ft1{left:-4px;top:50px;background:var(--green-pale);animation:bob 5.5s ease-in-out .3s infinite}
.ft2{right:-2px;top:150px;background:var(--orange-pale);animation:bob 6.2s ease-in-out .8s infinite}
.ft3{left:6px;bottom:30px;animation:bob 5s ease-in-out 1.2s infinite}

/* ---------- 数据绿带 ---------- */
.metrics{background:linear-gradient(135deg,var(--green-deep) 0%,var(--green-dark) 100%);position:relative;overflow:hidden}
.metrics::before{
  content:"";position:absolute;top:-40px;right:-30px;width:200px;height:200px;border-radius:50%;
  background:rgba(255,255,255,.06);
}
.metrics-grid{display:grid;grid-template-columns:repeat(4,1fr);padding:30px 0;position:relative}
.metrics-grid li{text-align:center;padding:6px 10px;border-left:1px solid rgba(255,255,255,.16)}
.metrics-grid li:first-child{border-left:0}
.metrics-grid b{display:block;font-size:30px;font-weight:900;color:#fff}
.metrics-grid b i{font-style:normal;font-size:15px;color:var(--green-bright);margin-left:2px}
.metrics-grid span{font-size:13px;color:rgba(255,255,255,.72)}

/* ---------- 区块通用 ---------- */
.section{padding:80px 0}
.section-alt{background:var(--green-mist)}
.sec-head{max-width:660px;margin-bottom:46px}
.sec-kicker{
  display:inline-flex;align-items:center;gap:8px;font-size:13px;font-weight:800;
  letter-spacing:2.5px;color:var(--green-deep);text-transform:uppercase;margin-bottom:12px;
}
.sec-kicker::before{content:"";width:26px;height:4px;border-radius:4px;background:var(--orange)}
.sec-head h2{font-size:clamp(27px,3.3vw,37px);line-height:1.28;color:var(--ink);font-weight:900}
.block-title{font-size:clamp(24px,2.9vw,32px);line-height:1.3;color:var(--ink);font-weight:900}
.sec-head p{margin-top:13px;font-size:15px;color:var(--ink-2)}

/* ---------- 平台核心特色：3列交错 ---------- */
.feat-grid{display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:auto auto;gap:22px}
.feat{
  position:relative;border:2px solid var(--ink);border-radius:var(--radius-lg);
  padding:30px 28px 26px;background:#fff;overflow:hidden;transition:transform .2s;
}
.feat:hover{transform:translateY(-5px)}
.feat-tall{grid-row:span 2;display:flex;flex-direction:column}
.feat-mid{grid-row:span 1}
.feat-shift{margin-top:30px}
.feat-idx{
  position:absolute;top:14px;right:20px;font-size:50px;font-weight:900;line-height:1;
  color:transparent;-webkit-text-stroke:1.5px rgba(31,42,23,.22);
}
.feat-icon{
  width:48px;height:48px;border-radius:12px;background:var(--green-pale);
  display:flex;align-items:center;justify-content:center;margin-bottom:16px;border:1.5px solid var(--green-deep);
}
.feat-icon svg{width:24px;height:24px;stroke:var(--green-deep)}
.feat h3{font-size:18.5px;font-weight:800;margin-bottom:10px}
.feat p{font-size:14.5px;color:var(--ink-2)}
.feat:nth-child(2){background:var(--orange-pale)}
.feat:nth-child(2) .feat-icon{background:#fff;border-color:var(--orange-deep)}
.feat:nth-child(2) .feat-icon svg{stroke:var(--orange-deep)}
.feat:nth-child(4){background:var(--ink);color:#fff}
.feat:nth-child(4) h3{color:var(--green-bright)}
.feat:nth-child(4) p{color:rgba(255,255,255,.82)}
.feat:nth-child(4) .feat-icon{background:var(--green-deep);border-color:var(--green-bright)}
.feat:nth-child(4) .feat-icon svg{stroke:var(--green-bright)}
.feat:nth-child(4) .feat-idx{-webkit-text-stroke:1.5px rgba(156,204,101,.32)}

/* ---------- 题材书库 ---------- */
.tag-cloud{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:40px}
.tc{
  font-size:15px;font-weight:800;padding:9px 22px;border-radius:999px;border:2px solid var(--ink);
  transition:transform .15s;
}
.tc:hover{transform:translateY(-3px)}
.tc-a{background:var(--green);color:#fff}
.tc-b{background:var(--orange);color:#fff}
.tc-c{background:#fff;color:var(--ink)}
.shelf-cards{display:grid;grid-template-columns:repeat(5,1fr);gap:18px}
.sc-card{
  background:#fff;border:2px solid var(--ink);border-radius:var(--radius-md);
  overflow:hidden;transition:transform .2s;
}
.sc-card:hover{transform:translateY(-5px)}
.sc-cover{height:130px;border-bottom:2px solid var(--ink)}
.sc1{background:linear-gradient(150deg,#9CCC65,var(--green-dark))}
.sc2{background:linear-gradient(150deg,#FFE0B2,var(--orange-deep))}
.sc3{background:linear-gradient(150deg,#B0BEC5,#37474F)}
.sc4{background:linear-gradient(150deg,#F8BBD0,#AD1457)}
.sc5{background:linear-gradient(150deg,#C5E1A5,#33691E)}
.sc-card b{display:block;font-size:13px;font-weight:800;padding:9px 12px 2px}
.sc-card span{display:block;font-size:11px;color:var(--ink-mist);padding:0 12px 10px}

/* ---------- 应用内实拍内容 ---------- */
.shots-scroll{display:flex;gap:22px;overflow-x:auto;padding:6px 4px 22px;scroll-snap-type:x mandatory}
.shots-scroll::-webkit-scrollbar{height:8px}
.shots-scroll::-webkit-scrollbar-track{background:#fff;border-radius:99px;border:1px solid var(--line)}
.shots-scroll::-webkit-scrollbar-thumb{background:var(--green);border-radius:99px}
.shot-card{
  flex:0 0 auto;width:260px;scroll-snap-align:start;background:#fff;
  border:2px solid var(--ink);border-radius:var(--radius-md);overflow:hidden;transition:transform .2s;
}
.shot-card:hover{transform:translateY(-5px)}
.shot-card img{width:100%;max-width:260px;height:auto;margin:0 auto;padding-top:10px}
.shot-card figcaption{
  font-size:13px;font-weight:700;color:var(--ink);background:var(--green-pale);
  border-top:2px solid var(--ink);padding:11px 16px;text-align:center;
}
.shots-hint{display:flex;align-items:center;gap:9px;font-size:13px;color:var(--ink-mist);margin-top:6px}
.shots-hint i{width:30px;height:3px;border-radius:3px;background:var(--green)}

/* ---------- 来自用户的评价：2列评分卡 ---------- */
.review-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px}
.review-card{
  display:flex;gap:18px;align-items:flex-start;background:#fff;
  border:2px solid var(--ink);border-radius:var(--radius-lg);padding:24px;
}
.rv-ring{
  flex-shrink:0;width:64px;height:64px;border-radius:50%;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  background:#fff;border:3px solid var(--green-deep);position:relative;
}
.rv-ring::before{content:"";position:absolute;inset:-6px;border-radius:50%;border:2px dashed var(--green)}
.rv-ring b{font-size:18px;font-weight:900;color:var(--green-deep);line-height:1.1}
.rv-ring span{font-size:9.5px;color:var(--ink-mist);font-weight:700}
.rv-ring-b{border-color:var(--orange-deep)}
.rv-ring-b::before{border-color:var(--orange)}
.rv-ring-b b{color:var(--orange-deep)}
.rv-body{flex:1;min-width:0}
.rv-body p{font-size:14.5px;color:var(--ink-2)}
.rv-foot{display:flex;align-items:center;gap:12px;margin-top:12px;padding-top:10px;border-top:1.5px dashed var(--line)}
.rv-foot b{font-size:13.5px;font-weight:800;color:var(--ink)}
.rv-foot span{font-size:12px;color:var(--ink-mist)}

/* ---------- 常见问题：节点连线式 ---------- */
.faq-list{max-width:880px;margin:0 auto;position:relative;padding-left:8px}
.faq-list::before{
  content:"";position:absolute;left:26px;top:24px;bottom:24px;width:2px;
  background:linear-gradient(180deg,var(--green),var(--green-deep));opacity:.35;
}
.faq-item{position:relative;margin-bottom:14px}
.faq-item > button{
  width:100%;display:flex;align-items:center;gap:14px;text-align:left;
  background:#fff;border:2px solid var(--ink);border-radius:var(--radius-md);
  cursor:pointer;padding:16px 22px 16px 14px;font-family:inherit;
  font-size:15.5px;font-weight:700;color:var(--ink);position:relative;z-index:1;
}
.faq-node{
  font-style:normal;flex-shrink:0;width:38px;height:38px;border-radius:50%;
  display:flex;align-items:center;justify-content:center;font-size:11.5px;font-weight:900;
  background:var(--green-deep);color:#fff;border:3px solid #fff;box-shadow:0 0 0 2px var(--green-deep);
}
.faq-item.open .faq-node{background:var(--orange-deep);box-shadow:0 0 0 2px var(--orange-deep)}
.faq-item > button span{flex:1}
.faq-item > button em{
  font-style:normal;flex-shrink:0;width:24px;height:24px;position:relative;
}
.faq-item > button em::before,
.faq-item > button em::after{
  content:"";position:absolute;top:50%;left:50%;width:13px;height:2.5px;border-radius:2px;
  background:var(--green-deep);transform:translate(-50%,-50%);transition:transform .25s;
}
.faq-item > button em::after{transform:translate(-50%,-50%) rotate(90deg)}
.faq-item.open > button em::after{transform:translate(-50%,-50%) rotate(0deg)}
.faq-item.open > button{border-color:var(--orange-deep)}
.faq-body{max-height:0;overflow:hidden;transition:max-height .35s ease}
.faq-body p{font-size:14.5px;color:var(--ink-2);padding:0 24px 18px 66px;margin:0 22px 0;border-top:1.5px dashed var(--line);padding-top:14px}

/* ---------- 品牌站点入口下载：圆钮居中banner ---------- */
.dl-banner{
  display:flex;align-items:center;gap:34px;justify-content:space-between;
  background:linear-gradient(135deg,var(--green) 0%,var(--green-deep) 100%);
  border:3px solid var(--ink);border-radius:var(--radius-lg);padding:36px 46px;
  position:relative;overflow:hidden;
}
.dl-banner::before{
  content:"";position:absolute;top:-50px;left:-30px;width:200px;height:200px;border-radius:50%;
  background:rgba(255,255,255,.1);
}
.dl-banner::after{
  content:"";position:absolute;bottom:-60px;right:20%;width:160px;height:160px;border-radius:50%;
  background:rgba(255,112,67,.2);
}
.dl-mascot{position:relative;z-index:1;flex-shrink:0;width:84px;height:84px;border-radius:50%;background:#fff;border:3px solid var(--ink);display:flex;align-items:center;justify-content:center;box-shadow:var(--shadow-soft)}
.dl-mascot img{width:62px;height:62px;border-radius:50%}
.dl-copy{position:relative;z-index:1;flex:1}
.dl-copy h2{font-size:26px;font-weight:900;color:#fff}
.dl-copy p{margin-top:10px;font-size:14.5px;color:rgba(255,255,255,.88);max-width:540px}
.dl-cta{
  position:relative;z-index:1;display:inline-flex;align-items:center;gap:10px;
  background:#fff;color:var(--green-deep);font-size:17px;font-weight:900;
  padding:18px 38px;border-radius:999px;border:3px solid var(--ink);
  box-shadow:0 6px 0 var(--green-dark);transition:transform .15s,box-shadow .15s;
}
.dl-cta:hover{transform:translateY(2px);box-shadow:0 4px 0 var(--green-dark)}
.dl-cta svg{width:19px;height:19px}

/* ---------- 页脚 ---------- */
.site-footer{background:var(--ink);color:rgba(255,255,255,.72);padding:58px 0 34px;border-top:4px solid var(--green)}
.footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:40px;padding-bottom:36px;border-bottom:1.5px solid rgba(255,255,255,.12)}
.footer-brand{display:flex;align-items:center;gap:11px;margin-bottom:14px}
.footer-brand img{width:42px;height:42px;border-radius:11px;border:2px solid rgba(255,255,255,.4)}
.footer-brand b{font-size:19px;font-weight:900;color:#fff}
.footer-desc{font-size:13.5px;line-height:1.9;max-width:420px}
.footer-col h4{font-size:14.5px;font-weight:800;color:var(--green-bright);margin-bottom:14px;letter-spacing:1px}
.footer-col a{display:block;font-size:13.5px;padding:5px 0;transition:color .2s}
.footer-col a:hover{color:var(--green-bright)}
.footer-base{padding-top:26px;text-align:center}
.footer-base .links{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 22px;margin-bottom:14px}
.footer-base .links a{font-size:12.5px;color:rgba(255,255,255,.5)}
.footer-base .links a:hover{color:var(--green-bright)}
.footer-base p{font-size:12.5px;color:rgba(255,255,255,.5);margin-top:6px}

/* ---------- 返回顶部 ---------- */
.backtop{
  position:fixed;right:24px;bottom:160px;z-index:55;width:46px;height:46px;border-radius:50%;
  background:var(--green-deep);border:2px solid #fff;cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  opacity:0;visibility:hidden;transform:translateY(14px);
  transition:opacity .3s,visibility .3s,transform .3s;
  box-shadow:0 4px 12px rgba(46,125,50,.4);
}
.backtop.show{opacity:1;visibility:visible;transform:none}
.backtop:hover{background:var(--green)}
.backtop svg{width:20px;height:20px}

/* ---------- 响应式 ---------- */
@media (max-width:1024px){
  .hero-grid{grid-template-columns:1fr .9fr;gap:30px}
  .shelf-cards{grid-template-columns:repeat(3,1fr)}
}
@media (max-width:860px){
  .primary-nav{display:none;position:absolute;top:70px;left:0;right:0;flex-direction:column;
    background:#fff;border-bottom:3px solid var(--green-deep);padding:12px 5%;gap:2px}
  .primary-nav.open{display:flex}
  .primary-nav a{padding:12px 14px;border-radius:10px}
  .menu-toggle{display:flex}
  .header-cta{display:none}
  .hero-grid{grid-template-columns:1fr;padding:44px 0 60px}
  .hero-lead{max-width:none}
  .hero-stat{width:100%}
  .hero-stat li{flex:1;padding:10px 14px}
  .shelf-stage{min-height:0;margin-top:10px;padding:16px 4px 24px}
  .shelf{max-width:340px}
  .shelf-row{height:96px;gap:4px}
  .book-spine{width:28px}
  .book-spine span{max-height:78px}
  .mascot{width:48px;height:48px;right:10px}
  .mascot img{width:34px;height:34px}
  .open-book{width:190px}
  .feat-grid{grid-template-columns:1fr;grid-template-rows:none}
  .feat-tall{grid-row:auto}
  .feat-shift{margin-top:0}
  .shelf-cards{grid-template-columns:repeat(2,1fr)}
  .review-grid{grid-template-columns:1fr}
  .dl-banner{flex-direction:column;align-items:flex-start;gap:22px;padding:30px 26px}
  .dl-cta{align-self:flex-start}
  [id]{scroll-margin-top:72px}
  .backtop{right:16px;bottom:150px}
}