/* ==========================================================================
   Engram 首页站 · 单一样式表（零 JS、零内联样式、零第三方资源）
   首页 v2：Hero 双栏（文案 + 记忆轨迹视觉锚点）、机制 Bento、三端三卡、
   实况设备框、信任区、底部 CTA 带。
   合规长文页（privacy / terms）沿用 .doc 命名空间，行为保持不变。
   动效只用纯 CSS，且在 prefers-reduced-motion: reduce 下全部关闭。
   ========================================================================== */
:root{
  --bg:#06090F; --bg2:#0A0F18;
  --panel:rgba(255,255,255,.035);
  --panel-2:rgba(255,255,255,.055);
  --line:rgba(255,255,255,.10);
  --line-2:rgba(255,255,255,.18);
  --ink:#EAF1FB; --muted:#93A2B8; --dim:#5C6A80;
  --accent:#5EEAD4; --accent-ink:#04120F; --accent-2:#7C9CFF;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
  --sans:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","HarmonyOS Sans SC","Microsoft YaHei",sans-serif;
  --maxw:1120px;
  --r-sm:8px; --r:12px; --r-lg:18px;
  --shadow:0 24px 60px rgba(0,0,0,.45);
}
*{box-sizing:border-box}
html{background:var(--bg);-webkit-text-size-adjust:100%}
body{
  margin:0; color:var(--ink); font-family:var(--sans);
  font-size:16px; line-height:1.65;
  background:
    radial-gradient(1100px 560px at 22% -10%, rgba(94,234,212,.10), transparent 60%),
    radial-gradient(900px 520px at 92% 4%, rgba(124,156,255,.10), transparent 62%),
    linear-gradient(180deg,var(--bg2),var(--bg) 46%);
  -webkit-font-smoothing:antialiased; overflow-x:hidden;
}
h1,h2,h3{margin:0}
p{margin:0}
a{color:inherit;text-decoration:none}
img{display:block;max-width:100%}
.wrap{position:relative;z-index:1;max-width:var(--maxw);margin:0 auto;padding:0 32px}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:4px}

/* 背景栅格（低噪，mask 收敛到首屏） */
.grid{position:fixed;inset:0;pointer-events:none;z-index:0;opacity:.5;
  background-image:
    repeating-linear-gradient(60deg,rgba(255,255,255,.030) 0 1px,transparent 1px 52px),
    repeating-linear-gradient(-60deg,rgba(255,255,255,.030) 0 1px,transparent 1px 52px);
  -webkit-mask-image:radial-gradient(1200px 660px at 50% 2%,#000 10%,transparent 76%);
  mask-image:radial-gradient(1200px 660px at 50% 2%,#000 10%,transparent 76%)}

/* ---------- Header / Footer 共用 ---------- */
header{display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:20px 0 18px;border-bottom:1px solid var(--line)}
.brand{display:flex;align-items:center;gap:10px;font-family:var(--mono);
  letter-spacing:.30em;font-size:13px;color:var(--ink);text-transform:uppercase}
.mark{width:22px;height:22px;flex:0 0 22px}
.nav{display:flex;gap:24px;align-items:center;font-size:13.5px;color:var(--muted)}
.nav a{color:var(--muted);transition:color .18s ease}
.nav a:hover{color:var(--ink)}
.nav a.cta{color:var(--accent);border:1px solid rgba(94,234,212,.36);border-radius:var(--r-sm);
  padding:7px 15px;transition:background .18s ease,border-color .18s ease}
.nav a.cta:hover{background:rgba(94,234,212,.10);border-color:rgba(94,234,212,.6)}

/* ---------- Hero（双栏：文案 + 视觉锚点） ---------- */
.hero{display:grid;grid-template-columns:1.15fr .85fr;gap:52px;align-items:center;
  padding:70px 0 30px}
.eyebrow{display:inline-flex;align-items:center;gap:10px;font-family:var(--mono);
  font-size:11.5px;letter-spacing:.24em;color:var(--accent);text-transform:uppercase;margin:0 0 22px}
.eyebrow .dot{width:6px;height:6px;border-radius:50%;background:var(--accent);
  box-shadow:0 0 0 4px rgba(94,234,212,.14)}
h1{font-size:clamp(2.1rem,4.4vw,3.4rem);line-height:1.12;letter-spacing:-.024em;font-weight:680;
  max-width:16ch}
h1 .hl{color:var(--accent)}
.lead{margin:22px 0 30px;max-width:56ch;font-size:17px;line-height:1.72;color:var(--muted)}
.cta{display:flex;gap:14px;flex-wrap:wrap;align-items:center}
.btn{display:inline-flex;align-items:center;gap:9px;border-radius:var(--r-sm);padding:13px 24px;
  font-size:15px;font-weight:600;border:1px solid transparent;
  transition:transform .16s ease,background .18s ease,border-color .18s ease}
.btn svg{width:15px;height:15px}
.btn-primary{background:var(--accent);color:var(--accent-ink)}
.btn-primary:hover{transform:translateY(-2px)}
.btn-ghost{color:var(--ink);border-color:var(--line-2);background:var(--panel)}
.btn-ghost:hover{background:var(--panel-2);border-color:rgba(255,255,255,.30);transform:translateY(-2px)}
.sub{margin:20px 0 0;font-size:12.5px;color:var(--dim);font-family:var(--mono);letter-spacing:.03em}

/* Hero 视觉锚点：记忆轨迹 + 浮动数据卡 */
.visual{position:relative;min-height:360px}
.visual .trace{width:100%;height:auto;display:block}
.trace .ring{fill:none;stroke:rgba(94,234,212,.30);stroke-width:1.2}
.trace .ring.r2{stroke-dasharray:3 7}
.trace .axis{fill:none;stroke:rgba(124,156,255,.45);stroke-width:1.4;
  stroke-linecap:round;stroke-linejoin:round;
  stroke-dasharray:640;stroke-dashoffset:0;animation:drawin 2.2s ease-out .3s both}
.trace .node{fill:var(--accent)}
.trace .halo{fill:none;stroke:rgba(94,234,212,.30);stroke-width:1}
.float{position:absolute;min-width:130px;padding:12px 14px;border-radius:14px;
  background:linear-gradient(180deg,rgba(255,255,255,.075),rgba(255,255,255,.03));
  border:1px solid var(--line-2);box-shadow:var(--shadow);backdrop-filter:blur(10px)}
.float .k{font-family:var(--mono);font-size:10px;letter-spacing:.16em;color:var(--dim);text-transform:uppercase}
.float .v{font-size:22px;font-weight:680;letter-spacing:-.02em}
.float .v small{font-size:12px;color:var(--muted);font-weight:500;margin-left:3px}
.float.f1{top:6%;right:2%;animation:floaty 6s ease-in-out infinite}
.float.f2{bottom:16%;left:-4%;animation:floaty 7.5s ease-in-out infinite .6s}
.float.f3{bottom:-2%;right:16%;animation:floaty 6.8s ease-in-out infinite 1.1s;
  background:linear-gradient(135deg,rgba(94,234,212,.16),rgba(124,156,255,.12))}
.spark{display:flex;gap:3px;align-items:flex-end;height:22px;margin-top:6px}
.spark i{width:5px;border-radius:3px;background:linear-gradient(180deg,var(--accent),rgba(94,234,212,.25))}
.spark i:nth-child(1){height:40%}
.spark i:nth-child(2){height:64%}
.spark i:nth-child(3){height:34%}
.spark i:nth-child(4){height:82%}
.spark i:nth-child(5){height:58%}
.spark i:nth-child(6){height:96%}
@keyframes drawin{from{stroke-dashoffset:640}to{stroke-dashoffset:0}}
@keyframes floaty{0%,100%{transform:translateY(0)}50%{transform:translateY(-9px)}}

/* ---------- 通用小节 ---------- */
section{padding:70px 0 12px}
.sec-head{display:flex;align-items:baseline;justify-content:space-between;gap:20px;
  margin:0 0 28px;padding-bottom:14px;border-bottom:1px solid var(--line)}
.sec-head h2{font-size:clamp(1.35rem,2.4vw,1.7rem);letter-spacing:-.018em;font-weight:660}
.sec-head .lede{font-size:14px;color:var(--muted);max-width:44ch;text-align:right}

/* ---------- Bento（机制区） ---------- */
.bento{display:grid;grid-template-columns:repeat(6,1fr);gap:16px}
.card{position:relative;padding:24px;border-radius:var(--r-lg);background:var(--panel);
  border:1px solid var(--line);overflow:hidden;
  transition:transform .22s ease,border-color .22s ease,background .22s ease}
.card:hover{transform:translateY(-4px);border-color:var(--line-2);background:var(--panel-2)}
.card.span-4{grid-column:span 4}
.card.span-2{grid-column:span 2}
.card.span-6{grid-column:span 6}
.card .idx{font-family:var(--mono);font-size:10.5px;letter-spacing:.16em;color:var(--accent);
  text-transform:uppercase;display:block;margin-bottom:14px}
.card h3{font-size:17px;letter-spacing:-.01em;margin-bottom:9px}
.card p{font-size:14.2px;color:var(--muted);line-height:1.62}
.card .glow{position:absolute;inset:auto -20% -40% auto;width:220px;height:220px;border-radius:50%;
  background:radial-gradient(circle,rgba(94,234,212,.14),transparent 68%);pointer-events:none}
/* 卡片内嵌小图示 */
.mock{margin-top:16px;border-radius:10px;border:1px solid var(--line);background:rgba(0,0,0,.28);overflow:hidden}
.mock .bar{display:flex;gap:5px;padding:8px 10px;border-bottom:1px solid var(--line)}
.mock .bar i{width:8px;height:8px;border-radius:50%;background:rgba(255,255,255,.16)}
.mock .body{padding:12px 14px;font-family:var(--mono);font-size:11.5px;line-height:1.9;color:var(--muted)}
.mock .body .k{color:var(--accent)}
.mock .body .t{color:var(--dim)}
.qa{margin-top:16px;display:grid;gap:8px}
.qa .q,.qa .a{padding:11px 13px;border-radius:10px;font-size:13px;border:1px solid var(--line)}
.qa .q{background:var(--panel-2);color:var(--ink)}
.qa .a{background:rgba(94,234,212,.08);border-color:rgba(94,234,212,.28);color:var(--muted)}
.review-viz{margin-top:18px;display:flex;gap:26px;align-items:center}
.bars{flex:1;display:grid;gap:9px}
.bars .row{display:flex;align-items:center;gap:10px;font-size:11.5px;color:var(--dim);font-family:var(--mono)}
.bars .row .track{flex:1;height:7px;border-radius:999px;background:rgba(255,255,255,.08);overflow:hidden}
.bars .row .fill{display:block;height:100%;border-radius:999px;
  background:linear-gradient(90deg,var(--accent),var(--accent-2))}
.bars .row:nth-child(1) .fill{width:38%}
.bars .row:nth-child(2) .fill{width:72%}
.bars .row:nth-child(3) .fill{width:56%}
.donut{--p:78;flex:0 0 auto;width:84px;height:84px;border-radius:50%;position:relative;
  display:grid;place-items:center;
  background:conic-gradient(var(--accent) calc(var(--p)*1%), rgba(255,255,255,.09) 0)}
.donut::before{content:"";position:absolute;inset:9px;border-radius:50%;background:#0B1017}
.donut span{position:relative;font-family:var(--mono);font-size:17px;font-weight:700;color:var(--ink)}

/* ---------- 三端 ---------- */
.clients-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.client{padding:26px 24px}
.client .ico{width:38px;height:38px;border-radius:11px;display:grid;place-items:center;margin-bottom:16px;
  background:rgba(94,234,212,.10);border:1px solid rgba(94,234,212,.30);color:var(--accent)}
.client .ico svg{width:20px;height:20px}
.client h3{font-size:16px;margin-bottom:8px}
.client p{font-size:14px}
.client .meta{margin-top:14px;font-family:var(--mono);font-size:10.5px;letter-spacing:.14em;color:var(--dim)}
.note-line{margin:22px 0 0;font-size:14px;color:var(--muted)}

/* ---------- 实况（设备框 · 居中舞台） ---------- */
.stage{position:relative;max-width:840px;margin:6px auto 0;padding:30px 0 54px;display:flex;justify-content:center}
.stage::before{content:"";position:absolute;inset:-4% 6% 16%;border-radius:50%;pointer-events:none;
  background:radial-gradient(closest-side, rgba(94,234,212,.13), transparent 72%)}
.device{position:relative;background:#0b111a;border:1px solid var(--line-2);box-shadow:var(--shadow)}
.device img{display:block;width:100%;height:auto}
.device.laptop{width:min(560px,84%);border-radius:15px;padding:10px 10px 12px}
.device.laptop img{border-radius:6px}
.device.phone{position:absolute;right:2%;bottom:-6px;width:min(152px,24%);border-radius:20px;padding:7px;
  box-shadow:0 30px 60px rgba(0,0,0,.62)}
.device.phone img{border-radius:14px}

/* ---------- 信任 ---------- */
.trust-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.trust-grid .item{display:flex;gap:14px;align-items:flex-start;padding:20px;border-radius:var(--r);
  background:var(--panel);border:1px solid var(--line)}
.trust-grid .item .ico{flex:0 0 34px;width:34px;height:34px;border-radius:10px;display:grid;place-items:center;
  background:rgba(124,156,255,.12);border:1px solid rgba(124,156,255,.28);color:var(--accent-2)}
.trust-grid .item .ico svg{width:18px;height:18px}
.trust-grid h3{font-size:14.5px;margin-bottom:5px}
.trust-grid p{font-size:13px;color:var(--muted)}

/* ---------- 底部 CTA 带 ---------- */
.band{margin-top:64px;padding:44px 40px;border-radius:24px;text-align:center;position:relative;overflow:hidden;
  background:linear-gradient(135deg,rgba(94,234,212,.13),rgba(124,156,255,.10));
  border:1px solid var(--line-2)}
.band .glow{position:absolute;inset:-40% 30% auto 30%;height:260px;border-radius:50%;
  background:radial-gradient(circle,rgba(94,234,212,.22),transparent 66%);pointer-events:none}
.band h2{font-size:clamp(1.5rem,3vw,2.05rem);letter-spacing:-.02em;margin-bottom:12px}
.band p{color:var(--muted);max-width:52ch;margin:0 auto 26px;position:relative}
.band .cta{justify-content:center;position:relative}

/* ---------- Footer（与 privacy / terms 逐字一致） ---------- */
footer{margin-top:72px;border-top:1px solid var(--line);padding:30px 0 56px}
.filings{display:flex;gap:18px;flex-wrap:wrap;margin:0 0 14px;font-size:13px;color:var(--muted)}
.filings a{color:var(--muted)}
.filings a:hover{color:var(--ink)}
.gongan{display:inline-flex;align-items:center;gap:6px}
.mark-gongan{width:15px;height:15px;flex:0 0 15px}
.flinks{display:flex;gap:20px;flex-wrap:wrap;margin:0 0 16px;font-size:13px}
.flinks a{color:var(--muted)}
.flinks a:hover{color:var(--ink)}
.copy{margin:0;font-size:12.5px;color:var(--dim);font-family:var(--mono);letter-spacing:.02em}

/* ---------- 滚动揭示（纯 CSS；不支持则始终可见） ---------- */
@supports (animation-timeline: view()){
  @media (prefers-reduced-motion: no-preference){
    .reveal{animation:reveal-up .8s cubic-bezier(.22,.61,.36,1) both;
      animation-timeline:view();animation-range:entry 0% entry 65%}
  }
}
@keyframes reveal-up{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:none}}

/* ---------- 响应式 ---------- */
@media (max-width:900px){
  .wrap{padding:0 22px}
  .hero{grid-template-columns:1fr;gap:34px;padding-top:46px}
  .hero .visual{order:-1;min-height:300px}
  .float.f1{right:0}
  .float.f2{left:0}
  .float.f3{right:4%;bottom:0}
  .bento{grid-template-columns:1fr 1fr}
  .card.span-4,.card.span-2,.card.span-6{grid-column:span 2}
  .clients-grid,.trust-grid{grid-template-columns:1fr}
  .sec-head .lede{display:none}
  .device.laptop{width:100%}
  .device.phone{width:112px}
}
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation:none!important;transition:none!important}
}

/* ------------------------------------------------------------------
   合规长文页（privacy.html / terms.html）—— .doc 命名空间
   v2 改版未改动此段任何既有行为。
   ------------------------------------------------------------------ */
.doc{padding:64px 0 8px;max-width:78ch}
.doc h1{margin:0 0 20px;font-size:clamp(1.65rem,3.2vw,2.15rem);line-height:1.22;
  letter-spacing:-.018em;font-weight:650;max-width:none}
.doc h2{margin:38px 0 12px;padding-bottom:9px;font-size:16.5px;font-weight:600;
  letter-spacing:.005em;border-bottom:1px solid var(--line)}
.doc p{margin:0 0 13px;font-size:14.8px;color:var(--muted)}
.doc ul,.doc ol{margin:0 0 15px;padding-left:1.5em;font-size:14.8px;color:var(--muted)}
.doc li{margin:0 0 8px}
.doc li::marker{color:var(--dim)}
.doc strong{color:var(--ink);font-weight:600}
.doc table{width:100%;border-collapse:separate;border-spacing:0;margin:0 0 20px;
  font-size:13.6px;border:1px solid var(--line);border-radius:10px;overflow:hidden}
.doc th,.doc td{padding:10px 13px;text-align:left;vertical-align:top;
  color:var(--muted);border-bottom:1px solid var(--line)}
.doc th{color:var(--ink);font-weight:600;background:var(--panel)}
.doc tbody tr:last-child td{border-bottom:0}
@media (max-width:860px){
  .doc{padding-top:36px}
  .doc table{font-size:12.8px}
  .doc th,.doc td{padding:8px 10px}
}