/* 蓝海搜书 lhssa.cn —— 黑/白/海蓝/珊瑚橙 四色 · 斜切叠卡 · 时间轴骨架 */
:root{
  --ink:#12171d; --blue:#1c76d2; --blue-d:#0f5cab; --blue-l:#e8f2fc; --org:#f97316; --org-d:#dd5f08;
  --line:#e2e6ea; --muted:#5a6169; --alt:#f3f6f9;
  --num:Georgia,"Times New Roman",serif;
  --sans:"PingFang SC","Microsoft YaHei","Hiragino Sans GB",sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:var(--sans);color:var(--ink);background:#fff;line-height:1.7;font-size:16px;overflow-x:hidden}
img{display:block;max-width:100%}
a{text-decoration:none;color:inherit}
ul{list-style:none}
.wrap{max-width:1160px;margin:0 auto;padding:0 24px}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}

/* 顶栏 */
.hd{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.97);border-bottom:2px solid var(--ink)}
.hd-in{display:flex;align-items:center;gap:28px;height:72px}
.brand{display:flex;align-items:center;gap:12px;flex:none}
.brand img{border:2px solid var(--ink);border-radius:8px}
.brand-t{display:flex;flex-direction:column;line-height:1.25}
.brand-t strong{font-size:18px;font-weight:900}
.brand-t small{font-size:11px;color:var(--muted)}
.nav{display:flex;gap:24px;margin-left:auto}
.nav a{font-size:14.5px;font-weight:600;color:#3c434c;padding:4px 0;border-bottom:2px solid transparent}
.nav a:hover,.nav a.on{color:var(--blue);border-color:var(--blue)}
.hd-r{display:flex;align-items:center;gap:14px}
.btn{display:inline-flex;align-items:center;justify-content:center;font-weight:800;letter-spacing:1px;border:2px solid var(--ink);transition:transform .16s ease,box-shadow .16s ease,background .16s ease}
.btn-pri{background:var(--blue);color:#fff;padding:10px 22px;font-size:14px}
.btn-pri:hover{background:var(--blue-d)}
.btn-line{background:#fff;color:var(--ink);padding:10px 22px;font-size:14px}
.btn-line:hover{border-color:var(--org);color:var(--org-d)}
.btn-lg{padding:15px 34px;font-size:16px}
.burger{display:none;width:42px;height:38px;border:2px solid var(--ink);background:#fff;flex-direction:column;align-items:center;justify-content:center;gap:5px;cursor:pointer}
.burger span{display:block;width:18px;height:2px;background:var(--ink)}

/* 区块通用 */
.sec{padding:96px 0}
.sec-alt{background:var(--alt)}
.sec-h{max-width:680px;margin-bottom:48px}
.sec-h-c{margin-left:auto;margin-right:auto;text-align:center}
.sec-h-c .kick{justify-content:center}
.kick{display:flex;align-items:center;gap:12px;font-size:11px;font-weight:800;letter-spacing:2px;color:var(--muted);margin-bottom:16px}
.kick i{display:grid;place-items:center;min-width:34px;height:24px;padding:0 8px;background:var(--blue);color:#fff;font-style:normal;font-family:var(--num);font-size:12px}
.kick-c{justify-content:center}
.kick-w{color:rgba(255,255,255,.8)}
.kick-w i{background:var(--org);color:#fff}
.sec-h h2{font-size:38px;font-weight:900;line-height:1.3;letter-spacing:1px}
.sec-sub{margin-top:14px;font-size:15.5px;color:var(--muted)}

/* 英雄区 */
.hero{position:relative;background:#fff;padding:84px 0 96px;overflow:hidden}
.hero-in{display:grid;grid-template-columns:1fr 1fr;gap:44px;align-items:center}
.hero-l h1{font-size:62px;font-weight:900;letter-spacing:2px;line-height:1.15;margin:6px 0 20px}
.lead{font-size:15.5px;color:#3f454e;max-width:520px}
.hero-acts{display:flex;gap:14px;margin:30px 0 22px;flex-wrap:wrap}
.hero-points{display:flex;gap:22px;flex-wrap:wrap}
.hero-points li{position:relative;padding-left:16px;font-size:13.5px;font-weight:700;color:#333941}
.hero-points li::before{content:"";position:absolute;left:0;top:8px;width:7px;height:7px;background:var(--org)}
.hero-points li:nth-child(2)::before{background:var(--blue)}
.hero-points li:nth-child(3)::before{background:var(--ink)}

/* 英雄区右：斜切阶梯叠卡（范式③） */
.hero-r{display:flex;justify-content:flex-end}
.fan{position:relative;width:min(100%,460px);height:560px}
.fan-wm{position:absolute;left:-10px;bottom:6px;z-index:0;font-family:var(--num);font-size:88px;font-weight:700;letter-spacing:4px;color:transparent;-webkit-text-stroke:2px rgba(18,23,29,.08);user-select:none;pointer-events:none}
.fan-pad{position:absolute;top:70px;right:0;width:70%;height:74%;background:var(--blue-l);border:2px solid var(--ink)}
.fan-pad::before{content:"";position:absolute;top:-2px;right:-2px;width:44%;height:12px;background:var(--blue)}
.fan-card{position:absolute;margin:0;background:#fff;border:2px solid var(--ink)}
.fan-card img{width:100%;height:300px;object-fit:cover;object-position:top}
.fan-card figcaption{font-family:var(--num);font-size:10px;font-weight:700;letter-spacing:2px;padding:8px 10px;border-top:1px solid var(--line);color:var(--muted)}
.fan-a{top:26px;left:0;z-index:2;width:172px;transform:rotate(-6deg);box-shadow:8px 8px 0 var(--org)}
.fan-b{top:96px;right:18px;z-index:1;width:180px;transform:rotate(5deg);box-shadow:-8px 10px 0 rgba(28,118,210,.9)}
.fan-c{bottom:34px;left:110px;z-index:3;width:196px;transform:rotate(-2deg);box-shadow:12px 12px 0 var(--ink)}
.fan-a img{height:252px}
.fan-b img{height:262px}
.fan-no{position:absolute;top:-16px;right:64px;z-index:4;font-family:var(--num);font-size:52px;font-weight:700;color:var(--blue);-webkit-text-stroke:1.5px var(--ink);letter-spacing:1px}
.fan-badge{position:absolute;right:-12px;bottom:88px;z-index:4;background:var(--org);color:#fff;font-size:12px;font-weight:800;letter-spacing:2px;padding:8px 14px;border:2px solid var(--ink)}
.fan-tip{position:absolute;left:-8px;bottom:-6px;z-index:4;background:#fff;border:2px solid var(--ink);padding:12px 16px;box-shadow:6px 6px 0 var(--blue)}
.fan-tip b{display:block;font-size:15px;font-weight:900;color:var(--blue-d)}
.fan-tip span{font-size:11.5px;color:var(--muted)}

/* 01 搜书三步：横排编号带 */
.steps{background:var(--ink);padding:88px 0;border-top:8px solid var(--org);border-bottom:8px solid var(--blue)}
.steps .sec-h-c h2{color:#fff}
.steps .sec-sub{color:#98a0ab}
.st-row{display:flex;align-items:stretch;justify-content:center;gap:18px}
.st{flex:0 1 300px;background:#fff;border:2px solid var(--ink);padding:34px 28px;text-align:center;box-shadow:6px 6px 0 var(--blue)}
.st-b{box-shadow:6px 6px 0 var(--org)}
.st b{display:inline-grid;place-items:center;width:52px;height:52px;border-radius:50%;background:var(--blue);color:#fff;font-size:20px;font-weight:900;margin-bottom:16px}
.st-b b{background:var(--org)}
.st h3{font-size:21px;font-weight:900;margin-bottom:10px}
.st p{font-size:14px;color:var(--muted)}
.st-arrow{align-self:center;font-size:30px;font-weight:900;color:var(--org)}

/* 02 本领棋盘：2x3 交替底色 */
.bd-grid{display:grid;grid-template-columns:repeat(3,1fr);border:2px solid var(--ink);background:#fff;box-shadow:-12px 12px 0 var(--blue)}
.bd{padding:36px 30px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}
.bd:nth-child(3n){border-right:none}
.bd:nth-child(n+4){border-bottom:none}
.bd span{display:inline-block;font-family:var(--num);font-size:13px;font-weight:700;letter-spacing:2px;color:var(--org);margin-bottom:14px;padding-bottom:8px;border-bottom:3px solid var(--org)}
.bd-alt{background:var(--blue-l)}
.bd-alt span{color:var(--blue-d);border-bottom-color:var(--blue)}
.bd h3{font-size:20px;font-weight:900;margin-bottom:10px}
.bd p{font-size:14px;color:var(--muted)}

/* 03 界面双列：错落瀑布 */
#shots{border-bottom:12px solid var(--org)}
.duo{display:grid;grid-template-columns:1fr 1fr;gap:26px;padding:24px;background:#fff;border:2px solid var(--ink);box-shadow:14px 14px 0 var(--blue)}
.duo-col{display:flex;flex-direction:column;gap:26px}
.duo-col2{margin-top:64px}
.duo-x{position:relative;margin:0;background:#fff;border:1px solid var(--line)}
.duo-x img{width:auto;max-width:309px;height:430px;object-fit:cover;object-position:top;margin:0 auto;display:block}
.duo-no{position:absolute;top:-13px;left:16px;z-index:2;background:var(--org);color:#fff;font-family:var(--num);font-size:11px;font-weight:700;letter-spacing:2px;padding:5px 12px;border:2px solid var(--ink)}
.duo-col2 .duo-no{background:var(--blue)}
.duo-x img{height:430px}
.duo-x figcaption{padding:12px 14px;font-size:13px;font-weight:700;border-top:1px solid var(--line)}

/* 04 FAQ：页码编号 details */
.tq-list{max-width:820px;margin:0 auto;background:#fff;border:2px solid var(--ink);box-shadow:-10px -10px 0 var(--org),10px 10px 0 var(--blue)}
.tq{border-top:1px solid var(--line)}
.tq:first-child{border-top:none}
.tq summary{display:flex;align-items:center;gap:18px;padding:19px 26px;cursor:pointer;font-size:15.5px;font-weight:700;list-style:none}
.tq summary::-webkit-details-marker{display:none}
.tq-no{flex:none;font-family:var(--num);font-size:14px;font-weight:700;color:#fff;background:var(--blue);padding:3px 9px}
.tq:nth-child(even) .tq-no{background:var(--org)}
.tq[open]{background:var(--blue-l)}
.tq[open] .tq-no{background:var(--ink)}
.tq-a{padding:0 26px 22px 68px}
.tq-a p{font-size:14.5px;color:#3f454e}

/* 05 潮汐留言：中轴时间线左右交替 */
.tide{position:relative;max-width:860px;margin:0 auto;padding:8px 0}
.tide-line{position:absolute;top:0;bottom:0;left:50%;width:2px;background:var(--blue);transform:translateX(-50%)}
.tw{position:relative;width:47%;margin-left:auto;padding:0 0 26px 0}
.tw-l{margin-left:0;margin-right:auto}
.tw-dot{position:absolute;top:22px;width:14px;height:14px;border-radius:50%;background:var(--org);border:3px solid #fff;outline:2px solid var(--ink);z-index:2}
.tw .tw-dot{left:-11px}
.tw-l .tw-dot{right:-11px}
.tw-card{background:#fff;border:2px solid var(--ink);padding:20px 22px 14px}
.tw .tw-card{box-shadow:7px 7px 0 var(--blue-l),7px 7px 0 2px var(--ink)}
.tw-l .tw-card{box-shadow:-7px 7px 0 rgba(249,115,22,.25),-7px 7px 0 2px var(--ink)}
.tw-card p{font-size:14px;color:#343a42}
.tw-card footer{display:flex;justify-content:space-between;margin-top:12px;padding-top:10px;border-top:1px dashed var(--line);font-size:12px;color:var(--muted)}
.tw-card footer b{color:var(--ink)}
.tw-card footer time{font-family:var(--num)}

/* 06 下载拼接条 */
.get{padding:96px 0;background:#fff}
.get-strip{position:relative;display:flex;align-items:center;justify-content:space-between;gap:32px;background:var(--blue);border:2px solid var(--ink);padding:50px 56px;box-shadow:16px 16px 0 var(--org)}
.get-strip::before{content:"";position:absolute;left:-2px;top:-2px;bottom:-2px;width:12px;background:var(--ink)}
.get-txt h2{color:#fff;font-size:38px;font-weight:900;letter-spacing:2px;margin:8px 0 10px}
.get-txt p{color:rgba(255,255,255,.85);font-size:15px}
.btn-get{flex:none;background:#fff;color:var(--ink);padding:17px 44px;font-size:17px;box-shadow:7px 7px 0 var(--ink)}
.btn-get:hover{transform:translate(3px,3px);box-shadow:4px 4px 0 var(--ink)}
.get-note{display:block;text-align:right;margin-top:18px;font-size:12.5px;color:var(--muted);letter-spacing:1px}

/* 页脚 */
.ft{background:var(--ink);color:#fff;border-top:10px solid var(--blue)}
.ft-in{display:grid;grid-template-columns:1.4fr 1fr .6fr;gap:44px;padding:56px 24px 40px}
.ft-brand p{margin-top:16px;font-size:13.5px;color:#949aa3;max-width:340px}
.ft .brand-t small{color:#949aa3}
.ft-nav{display:flex;flex-direction:column;gap:10px}
.ft-nav a,.ft-links a{font-size:13.5px;color:#c6cbd2}
.ft-nav a:hover,.ft-links a:hover{color:var(--org)}
.ft-links{display:flex;flex-direction:column;gap:10px}
.ft-icp{padding:0 24px 10px;font-size:12.5px;color:#7a808a}
.ft-icp a{color:#7a808a}
.ft-icp a:hover{color:#fff}
.ft-c{padding:0 24px 30px;font-size:12.5px;color:#7a808a}

/* 返回顶部 */
.backtop{position:fixed;right:26px;bottom:26px;z-index:60;width:46px;height:46px;background:var(--org);color:#fff;border:2px solid var(--ink);font-size:20px;font-weight:900;cursor:pointer;opacity:0;visibility:hidden;transform:translateY(12px);transition:opacity .2s ease,transform .2s ease,visibility .2s}
.backtop.on{opacity:1;visibility:visible;transform:none}

/* 入场动画 */
.rv{opacity:0;transform:translateY(26px);transition:opacity .6s ease,transform .6s ease}
.rv.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  .rv{opacity:1;transform:none;transition:none}
  html{scroll-behavior:auto}
}

/* 响应式 */
@media (max-width:1024px){
  .hero-l h1{font-size:50px}
  .fan{width:min(100%,420px)}
  .bd-grid{grid-template-columns:repeat(2,1fr)}
  .bd:nth-child(3n){border-right:1px solid var(--line)}
  .bd:nth-child(2n){border-right:none}
  .bd:nth-child(n+4){border-bottom:1px solid var(--line)}
  .bd:nth-child(n+5){border-bottom:none}
  .st-row{flex-direction:column;align-items:stretch}
  .st{flex:none}
  .st-arrow{display:none}
  .duo-x img{height:380px}
}
@media (max-width:760px){
  .sec{padding:64px 0}
  .sec-h h2{font-size:28px}
  .hd-in{height:64px;gap:14px}
  .nav{position:fixed;top:64px;right:0;z-index:49;display:none;flex-direction:column;gap:0;background:#fff;border:2px solid var(--ink);border-right:none;padding:8px 0}
  .nav.open{display:flex}
  .nav a{padding:12px 28px;border-bottom:1px solid var(--line)}
  .burger{display:flex}
  .hd-cta{padding:8px 16px;font-size:13px}
  .hero{padding:44px 0 72px}
  .hero-in{grid-template-columns:1fr;gap:60px}
  .hero-l h1{font-size:38px}
  .hero-r{justify-content:center}
  .fan{width:min(100%,330px);height:470px;transform:scale(.92);transform-origin:top center}
  .fan-wm{font-size:52px}
  .fan-card img,.fan-a img,.fan-b img{height:190px}
  .fan-card{width:120px !important}
  .fan-c{width:132px !important}
  .fan-no{font-size:36px;right:30px}
  .fan-badge{right:-4px;bottom:64px;font-size:10.5px;padding:6px 10px}
  .fan-tip{left:0;bottom:-14px;padding:9px 12px}
  .steps{padding:64px 0}
  .st{padding:26px 20px}
  .bd-grid{grid-template-columns:1fr;box-shadow:none}
  .bd:nth-child(3n),.bd:nth-child(2n){border-right:none}
  .bd:nth-child(n+4){border-bottom:1px solid var(--line)}
  .bd:last-child{border-bottom:none}
  .duo{grid-template-columns:1fr;box-shadow:none;padding:16px;gap:20px}
  .duo-col2{margin-top:0}
  .duo-x img{height:400px}
  .tq-list{box-shadow:none}
  .tq summary{padding:16px 18px;gap:12px;font-size:14.5px}
  .tq-a{padding:0 18px 18px 56px}
  .tide-line{left:10px}
  .tw,.tw-l{width:auto;margin:0 0 0 34px;padding-bottom:22px}
  .tw .tw-dot{left:-31px}
  .tw-l .tw-dot{right:auto;left:-31px}
  .tw-card,.tw-l .tw-card{box-shadow:none}
  .get-strip{flex-direction:column;text-align:center;padding:44px 24px;box-shadow:10px 10px 0 var(--org)}
  .get-txt h2{font-size:28px}
  .get-note{text-align:center}
  .ft-in{grid-template-columns:1fr;gap:28px;padding:44px 24px 28px}
}