/* ============================================================
   膜枢 M1 · 如昼水衡 MBR 膜管家
   视觉语言：消费级科技产品官网（暗色电影感 + 克制的银黑）
   ============================================================ */

:root{
  --paper:#ffffff;
  --bg:#f4f5f6;
  --ink:#101418;
  --ink-2:#4b545b;
  --ink-3:#8b9399;
  --line:#e6e8ea;
  --dark:#07090b;
  --dark-2:#0e1216;
  --steel:#7fa8c0;
  --steel-2:#9fc2d6;
  --mono:"SF Mono",ui-monospace,Menlo,Consolas,monospace;
  --sans:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Arial,sans-serif;
  --ease:cubic-bezier(.22,.7,.25,1);
  --radius:18px;
  --subnav-h:56px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:var(--dark);
  color:var(--ink);
  font-family:var(--sans);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
::selection{background:#7fa8c0;color:#061018}
img,video{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
button{font-family:inherit}
h1,h2,h3,p{margin:0}

/* ---------- 主题变量（由 JS 在 body 上切换） ---------- */
body[data-theme="light"]{
  --nav-fg:#0c1013;
  --nav-bg:rgba(255,255,255,.86);
  --nav-border:rgba(0,0,0,.08);
}
body[data-theme="dark"]{
  --nav-fg:#f4f7f8;
  --nav-bg:rgba(10,12,14,.72);
  --nav-border:rgba(255,255,255,.10);
}

/* ---------- 吸顶产品导航 ---------- */
.subnav{
  position:fixed;top:0;left:0;right:0;z-index:60;
  height:var(--subnav-h);
  display:flex;align-items:center;justify-content:space-between;gap:20px;
  padding:0 clamp(16px,4vw,48px);
  color:var(--nav-fg);
  background:transparent;
  border-bottom:1px solid transparent;
  transition:background .4s var(--ease),border-color .4s var(--ease),color .4s var(--ease),backdrop-filter .4s;
}
.subnav.scrolled{
  background:var(--nav-bg);
  border-bottom-color:var(--nav-border);
  backdrop-filter:blur(18px) saturate(1.5);
  -webkit-backdrop-filter:blur(18px) saturate(1.5);
}
.subnav-brand{
  font-weight:700;font-size:16px;letter-spacing:.5px;
  display:flex;align-items:baseline;gap:6px;white-space:nowrap;
}
.subnav-brand .subnav-mark{color:var(--steel-2);font-weight:600}
.subnav-brand .subnav-name{font-weight:700}
.subnav-links{
  display:flex;gap:4px;flex-wrap:nowrap;
  position:absolute;left:50%;transform:translateX(-50%);
}
.subnav-links a{
  font-size:13px;letter-spacing:.3px;padding:8px 14px;border-radius:999px;
  opacity:.72;transition:opacity .25s,background .25s;
}
.subnav-links a:hover{opacity:1;background:rgba(128,146,158,.12)}
.subnav-links a.active{opacity:1;font-weight:600}
.subnav-cta{
  font-size:13px;font-weight:600;letter-spacing:.3px;
  padding:9px 20px;border-radius:999px;
  background:var(--nav-fg);color:var(--dark);white-space:nowrap;
  transition:transform .25s var(--ease),opacity .25s;
}
body[data-theme="light"] .subnav-cta{color:#fff;background:#0c1013}
.subnav-cta:hover{transform:translateY(-1px);opacity:.92}

/* ---------- Hero 首屏 ---------- */
.hero{
  position:relative;height:100vh;min-height:640px;
  display:flex;align-items:center;justify-content:center;
  overflow:hidden;color:#fff;text-align:center;
  background:#050608;
}
.hero-bg,.hero-bg video,.hero-shade{position:absolute;inset:0;width:100%;height:100%}
.hero-bg video{object-fit:cover;object-position:center}
.hero-shade{
  background:
    radial-gradient(120% 80% at 50% 30%,transparent 0%,rgba(5,6,8,.35) 70%,rgba(5,6,8,.85) 100%),
    linear-gradient(180deg,rgba(5,6,8,.55) 0%,rgba(5,6,8,.15) 30%,rgba(5,6,8,.2) 70%,rgba(5,6,8,.9) 100%);
}
.hero-content{position:relative;z-index:2;padding:0 24px;max-width:1000px}
.hero-eyebrow{
  font-family:var(--mono);font-size:12px;letter-spacing:4px;color:#c9d5da;
  text-transform:uppercase;margin-bottom:22px;
}
.hero-title{
  font-size:clamp(56px,11vw,140px);font-weight:800;line-height:.95;
  letter-spacing:-.04em;color:#fff;margin-bottom:24px;
}
.hero-title span{color:transparent;-webkit-text-stroke:1.5px #cfe0e9}
.hero-sub{
  font-size:clamp(17px,2.4vw,24px);font-weight:400;letter-spacing:.5px;
  color:#e6edf0;margin-bottom:44px;
}
.hero-actions{
  display:flex;gap:14px;justify-content:center;flex-wrap:wrap;
}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;
  min-width:160px;height:48px;padding:0 26px;border-radius:999px;
  font-size:14px;font-weight:600;letter-spacing:.3px;
  cursor:pointer;border:1px solid transparent;
  transition:transform .25s var(--ease),background .25s,border-color .25s,opacity .25s;
}
.btn:hover{transform:translateY(-2px)}
.btn-primary{background:#fff;color:#0c1013}
.btn-primary:hover{background:#e8eef1}
.btn-primary .ico-play{font-style:normal;font-size:11px;transform:translateY(1px)}
.btn-ghost{
  background:rgba(255,255,255,.08);color:#fff;
  border-color:rgba(255,255,255,.28);
  backdrop-filter:blur(8px);
}
.btn-ghost:hover{background:rgba(255,255,255,.16);border-color:rgba(255,255,255,.4)}

.hero-scroll{
  position:absolute;bottom:34px;left:50%;transform:translateX(-50%);z-index:2;
  width:26px;height:44px;border:2px solid rgba(255,255,255,.35);border-radius:20px;
}
.hero-scroll span{
  position:absolute;left:50%;top:8px;width:3px;height:9px;border-radius:2px;
  background:#fff;margin-left:-1.5px;
  animation:scrollhint 1.8s var(--ease) infinite;
}
@keyframes scrollhint{0%{transform:translateY(0);opacity:1}70%{transform:translateY(14px);opacity:0}100%{opacity:0}}

/* ---------- 标题文字区（浅色） ---------- */
.textband{
  background:var(--paper);color:var(--ink);
  padding:clamp(72px,10vw,150px) clamp(20px,6vw,72px);
  text-align:center;display:flex;flex-direction:column;align-items:center;
}
.textband .kicker{color:var(--ink-3)}
.kicker{
  font-family:var(--mono);font-size:11px;letter-spacing:3px;
  text-transform:uppercase;margin-bottom:22px;
}
.textband-title{
  font-size:clamp(32px,5vw,56px);font-weight:700;letter-spacing:-.02em;
  margin-bottom:26px;
}
.textband-lead{
  font-size:clamp(18px,2.4vw,24px);font-weight:500;line-height:1.6;
  color:var(--ink);max-width:820px;margin-bottom:20px;
}
.textband-desc{
  font-size:15px;line-height:2;color:var(--ink-2);max-width:760px;
}

/* ---------- 六大能力卡片（12 列马赛克） ---------- */
.features{background:var(--paper);padding:24px clamp(12px,3vw,40px) 0}
.features-grid{
  display:grid;grid-template-columns:repeat(12,minmax(0,1fr));
  grid-template-rows:repeat(3,min(26vw,340px));
  gap:12px;max-width:1440px;margin:0 auto;
}
.card{
  position:relative;overflow:hidden;border-radius:var(--radius);
  background:#0a0d10;display:block;cursor:pointer;
  transform:translateZ(0);
}
.card img{
  position:absolute;inset:0;width:100%;height:100%;object-fit:cover;
  transition:transform 1s var(--ease),filter .6s ease;
  filter:saturate(.92) brightness(.82);
}
.card::after{
  content:"";position:absolute;inset:0;
  background:linear-gradient(180deg,rgba(8,10,12,0) 30%,rgba(8,10,12,.55) 100%);
  transition:opacity .5s ease;
}
.card:hover img{transform:scale(1.06);filter:saturate(1) brightness(.9)}
.card-text{
  position:absolute;left:0;right:0;bottom:0;z-index:2;
  padding:clamp(20px,2.6vw,34px);color:#fff;
}
.card-kicker{
  display:inline-block;font-family:var(--mono);font-size:10px;letter-spacing:3px;
  color:#c9d6dc;text-transform:uppercase;margin-bottom:10px;
}
.card-text h3{
  font-size:clamp(18px,2.4vw,26px);font-weight:700;letter-spacing:-.01em;
}
.span7{grid-column:span 7}
.span5{grid-column:span 5}
.span6{grid-column:span 6}

/* ---------- 缩放滚动章节（标志性动效） ---------- */
.zoom{background:var(--dark)}
.zoom-track{height:240vh;position:relative}
.zoom-sticky{
  position:sticky;top:0;height:100vh;overflow:hidden;
}
.zoom-bg{
  position:absolute;inset:-6% 0;background-size:cover;background-position:center;
  will-change:transform,filter,opacity;
  transform:scale(1.28);filter:blur(9px);opacity:.28;
}
.zoom-copy{
  position:absolute;inset:0;z-index:3;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  text-align:center;color:#fff;padding:0 24px;
  will-change:transform,opacity;
}
.zoom-eyebrow{
  font-family:var(--mono);font-size:11px;letter-spacing:4px;
  color:#c9d6dc;text-transform:uppercase;margin-bottom:26px;
}
.zoom-headline{
  font-size:clamp(48px,9vw,120px);font-weight:800;line-height:1.02;
  letter-spacing:-.035em;margin-bottom:30px;
}
.zoom-desc{
  font-size:clamp(15px,1.7vw,19px);line-height:1.8;color:#e4ecef;
  max-width:640px;
}
.zoom-mask{
  position:absolute;left:0;right:0;bottom:-1px;height:34vh;z-index:4;
  background:linear-gradient(180deg,rgba(255,255,255,0),rgba(255,255,255,.96));
  opacity:0;will-change:opacity;pointer-events:none;
}
.zoom-after{background:var(--paper);position:relative;z-index:5}
.copygrid{
  display:grid;grid-template-columns:repeat(3,1fr);gap:0;
  max-width:1440px;margin:0 auto;
}
.copycard{
  padding:clamp(40px,5vw,72px) clamp(24px,3.4vw,52px);
  border-left:1px solid var(--line);
}
.copycard:first-child{border-left:0}
.copycard small{
  font-family:var(--mono);font-size:10px;letter-spacing:2.5px;
  color:var(--steel);text-transform:uppercase;display:block;margin-bottom:20px;
}
.copycard h3{font-size:20px;font-weight:700;margin-bottom:16px;line-height:1.5}
.copycard p{font-size:13.5px;line-height:1.95;color:var(--ink-2)}

/* ---------- 全屏媒体（结构动画） ---------- */
.mediafull{position:relative;min-height:100vh;overflow:hidden;color:#fff;background:#050608}
.mediafull-bg{position:absolute;inset:0}
.mediafull-bg video{position:absolute;inset:0;width:100%;height:100%;object-fit:contain;object-position:center;background:#000}
.mediafull-overlay{
  position:relative;z-index:2;min-height:100vh;
  display:flex;flex-direction:column;align-items:flex-start;justify-content:center;
  padding:120px clamp(20px,6vw,72px);
  max-width:760px;
}
.mediafull-overlay .kicker{color:#9fc2d6}
.mediafull-overlay h2{font-size:clamp(34px,5.5vw,60px);font-weight:800;letter-spacing:-.02em;margin-bottom:22px}
.mediafull-overlay>p{font-size:15px;line-height:1.95;color:#c3ced3;max-width:560px;margin-bottom:34px}
.mediafull-actions{display:flex;gap:14px;flex-wrap:wrap}
.mediafull-hint{
  position:absolute;left:clamp(20px,6vw,72px);bottom:34px;z-index:2;
  font-size:11px;letter-spacing:.5px;color:#8b979d;
}

/* ---------- 设备特点 ---------- */
.materials{background:var(--paper);padding:0 clamp(12px,3vw,40px) clamp(40px,6vw,80px)}
.material-grid{
  display:grid;grid-template-columns:repeat(3,1fr);gap:16px;max-width:1440px;margin:0 auto;
}
.material-card{
  background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);
  padding:clamp(18px,2vw,24px);
  transition:transform .4s var(--ease),box-shadow .4s;
}
.material-card:hover{transform:translateY(-5px);box-shadow:0 24px 50px rgba(16,20,24,.10)}
.material-no{
  display:block;font-family:var(--mono);font-size:11px;letter-spacing:2px;
  color:var(--ink-3);margin-bottom:14px;
}
.material-card h3{font-size:20px;font-weight:700;margin-bottom:14px}
.material-card p{font-size:13.5px;line-height:1.95;color:var(--ink-2)}
.material-figure{
  aspect-ratio:16/10;border-radius:calc(var(--radius) - 8px);
  overflow:hidden;background:#0a0d10;margin-bottom:24px;
}
.material-figure img{width:100%;height:100%;object-fit:cover;transition:transform .8s var(--ease)}
.material-card:hover .material-figure img{transform:scale(1.05)}

/* ---------- 现场应用 ---------- */
.field{background:var(--paper);padding:clamp(72px,9vw,140px) clamp(20px,6vw,72px) clamp(40px,6vw,80px)}
.field-head{max-width:820px;margin:0 auto clamp(40px,5vw,64px);text-align:center}
.field-head .kicker{color:var(--ink-3)}
.field-head h2{font-size:clamp(30px,4.5vw,52px);font-weight:700;letter-spacing:-.02em;margin-bottom:20px}
.field-head p{font-size:14.5px;line-height:2;color:var(--ink-2)}
.scene-gallery{max-width:1440px;margin:0 auto}
.scene-tabs{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;margin-bottom:20px}
.scene-tabs button{
  font-size:13px;color:var(--ink-2);background:var(--bg);
  border:1px solid transparent;cursor:pointer;
  padding:10px 20px;border-radius:999px;transition:all .25s;
}
.scene-tabs button:hover{background:#e9ecee;color:var(--ink)}
.scene-tabs button[aria-selected=true]{background:var(--dark);color:#fff}
.scene-stage{
  position:relative;border-radius:var(--radius);overflow:hidden;background:#07090b;
  aspect-ratio:16/9;
}
.scene-stage [role=tabpanel]{position:absolute;inset:0;animation:fadein .5s var(--ease)}
.scene-stage img{width:100%;height:100%;object-fit:cover}
.scene-stage p{
  position:absolute;left:0;right:0;bottom:0;padding:14px 22px;
  font-size:11px;letter-spacing:.5px;color:#c9d2d7;
  background:linear-gradient(180deg,transparent,rgba(7,9,11,.75));
}
@keyframes fadein{from{opacity:0}to{opacity:1}}
.scene-controls{
  display:flex;justify-content:center;align-items:center;gap:16px;margin-top:20px;
}
.scene-count{font-family:var(--mono);font-size:11px;letter-spacing:2px;color:var(--ink-3)}
.scene-controls button{
  width:40px;height:40px;border-radius:50%;border:1px solid var(--line);
  background:var(--paper);color:var(--ink-2);font-size:15px;cursor:pointer;
  transition:all .25s;
}
.scene-controls button:hover{background:var(--dark);color:#fff;border-color:var(--dark)}

/* ---------- 三视图与参数 ---------- */
.dims{background:var(--paper);padding:0 clamp(20px,6vw,72px) clamp(60px,7vw,100px)}
.dims-figure{
  max-width:1200px;margin:0 auto 24px;border:1px solid var(--line);
  border-radius:var(--radius);overflow:hidden;background:#fff;
}
.dims-figure img{width:100%;height:auto}
.dims-figure p{
  padding:14px 22px;font-size:11px;letter-spacing:.5px;color:var(--ink-3);
  background:var(--bg);
}
.specs{
  max-width:1200px;margin:0 auto;border-radius:var(--radius);
  background:var(--dark-2);color:#fff;padding:clamp(28px,4vw,48px) clamp(20px,4vw,52px);
  display:grid;grid-template-columns:repeat(4,1fr);gap:18px;
}
.specs>div{border-left:1px solid #2a333a;padding:6px 22px}
.specs>div:first-child{border-left:0;padding-left:0}
.specs strong{
  display:block;font-size:clamp(30px,4vw,44px);font-weight:300;letter-spacing:-.02em;
  font-variant-numeric:tabular-nums;line-height:1.1;color:#eef2f4;
}
.specs span{
  display:block;font-size:10.5px;letter-spacing:1.6px;line-height:1.7;
  color:#8b979d;margin-top:8px;font-family:var(--mono);
}

/* ---------- 品牌收尾 ---------- */
.brand{
  background:radial-gradient(120% 100% at 50% 0%,#141a1f 0%,#07090b 60%);
  color:#fff;text-align:center;
  padding:clamp(90px,13vw,170px) 24px;
}
.brand-eyebrow{
  font-family:var(--mono);font-size:11px;letter-spacing:5px;color:var(--steel-2);
  margin-bottom:28px;
}
.brand h2{
  font-size:clamp(52px,11vw,140px);font-weight:800;letter-spacing:-.04em;line-height:.95;
  margin-bottom:22px;
}
.brand-tagline{font-size:clamp(15px,1.8vw,19px);letter-spacing:2px;color:#c4cfd4;margin-bottom:48px}
.brand-actions{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}

/* ---------- 页脚 ---------- */
.footer{
  background:var(--paper);color:var(--ink);
  padding:clamp(50px,7vw,90px) clamp(20px,6vw,72px);
  text-align:center;
}
.footer h2{font-size:clamp(22px,3vw,32px);font-weight:700;margin-bottom:18px}
.footer p{font-size:13px;line-height:2;color:var(--ink-2)}
.footer details{
  margin-top:36px;font-size:12px;color:var(--ink-3);line-height:1.9;
  border-top:1px solid var(--line);padding-top:24px;max-width:760px;margin-left:auto;margin-right:auto;text-align:left;
}
.footer summary{cursor:pointer;color:var(--ink-2);letter-spacing:.4px}
.footer summary:hover{color:var(--ink)}
.footer details a{color:var(--steel);text-decoration:underline}

/* ---------- 回到顶部 ---------- */
.top{
  position:fixed;bottom:26px;right:24px;z-index:50;
  width:46px;height:46px;border-radius:50%;
  display:flex;align-items:center;justify-content:center;
  background:rgba(12,16,19,.82);color:#eef2f4;border:1px solid rgba(255,255,255,.18);
  font-size:15px;backdrop-filter:blur(8px);
  box-shadow:0 10px 26px rgba(0,0,0,.3);
  opacity:0;pointer-events:none;transform:translateY(10px);
  transition:opacity .3s,transform .3s,background .25s;
}
.top.show{opacity:1;pointer-events:auto;transform:none}
.top:hover{background:var(--steel)}

/* ---------- 阅读进度 ---------- */
.reading-progress{
  position:fixed;left:0;top:0;height:2px;z-index:70;
  width:100%;transform:scaleX(0);transform-origin:left;
  background:linear-gradient(90deg,#7fa8c0,#9fc2d6);
  pointer-events:none;
}

/* ---------- 图片弹窗 ---------- */
dialog{
  border:0;padding:44px 0 0;background:#0e1114;
  max-width:96vw;max-height:96vh;color:#fff;border-radius:14px;overflow:hidden;
}
dialog::backdrop{background:rgba(0,0,0,.82);backdrop-filter:blur(6px)}
dialog img{max-width:94vw;max-height:84vh;object-fit:contain;display:block}
dialog button{
  position:absolute;right:14px;top:10px;color:#cfd8dc;
  background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.16);
  border-radius:999px;font-size:11.5px;cursor:pointer;padding:7px 16px;
  transition:background .25s;
}
dialog button:hover{background:rgba(255,255,255,.18)}
dialog[open]{animation:modal-in .25s var(--ease)}
@keyframes modal-in{from{opacity:0;transform:scale(.97)}to{opacity:1;transform:none}}

/* ---------- 入场动效 ---------- */
.reveal{opacity:0;transform:translateY(26px);transition:opacity .8s ease,transform .9s var(--ease)}
.reveal.visible{opacity:1;transform:none}
.material-card{transition-delay:var(--stagger,0ms)}

/* ---------- 响应式 ---------- */
@media(max-width:900px){
  .features-grid{grid-template-columns:1fr 1fr;grid-template-rows:none}
  .span7,.span5,.span6{grid-column:span 1}
  .card{aspect-ratio:4/3;height:auto}
  .copygrid{grid-template-columns:1fr}
  .copycard{border-left:0;border-top:1px solid var(--line)}
  .copycard:first-child{border-top:0}
  .material-grid{grid-template-columns:1fr}
  .subnav-links{display:none}
}
@media(max-width:560px){
  .btn{min-width:140px;height:44px;font-size:13px;padding:0 20px}
  .subnav-cta{font-size:12px;padding:8px 16px}
  .specs{grid-template-columns:1fr 1fr;gap:10px}
  .specs>div{border-left:0;padding:6px 0}
  .specs>div:nth-child(even){border-left:1px solid #2a333a;padding-left:18px}
  .mediafull-overlay{justify-content:flex-end;padding-bottom:80px}
}

/* ---------- 动效偏好 ---------- */
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal{opacity:1;transform:none;transition:none}
  .card img{transition:none}
  .card:hover img{transform:none}
  dialog[open]{animation:none}
  .hero-scroll span{animation:none}
}