:root{
  --vh-deep:#081B3A;
  --vh-ink:#030B1A;
  --vh-cyan:#26E0D6;
  --vh-orange:#FF8A3D;
  --vh-violet:#3A1E6E;
  --vh-mist:#EAF2FF;
  --vh-steel:#8FA3C7;
  --vh-teal:#0E6B74;
  --vh-ok:#4FD18B;
  --vh-warn:#FF5C7A;

  --vh-line:rgba(143,163,199,.22);
  --vh-line-strong:rgba(143,163,199,.4);

  --vh-font-display:'Archivo Narrow','Bebas Neue','Noto Sans SC',sans-serif;
  --vh-font-body:'Noto Sans SC','Source Han Sans SC',system-ui,-apple-system,'Segoe UI',sans-serif;
  --vh-font-mono:'IBM Plex Mono','Roboto Mono','Noto Sans Mono',ui-monospace,monospace;

  --vh-rail:276px;
  --vh-gutter:clamp(1.1rem,4vw,3.5rem);
  --vh-max:1240px;
  --vh-radius:3px;
  --vh-ease:cubic-bezier(.22,.61,.36,1);
}

*,*::before,*::after{box-sizing:border-box;}

html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
}

body{
  margin:0;
  min-height:100vh;
  padding-left:var(--vh-rail);
  font-family:var(--vh-font-body);
  font-size:clamp(15px,1.05vw,17px);
  font-weight:400;
  line-height:1.65;
  color:var(--vh-mist);
  background-color:var(--vh-deep);
  background-image:
    radial-gradient(1100px 620px at 88% -12%,rgba(58,30,110,.62),transparent 62%),
    radial-gradient(820px 520px at -8% 104%,rgba(14,107,116,.34),transparent 66%);
  background-attachment:fixed;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

h1,h2,h3,h4,h5,h6{
  margin:0 0 .5em;
  font-family:var(--vh-font-display);
  font-weight:800;
  line-height:1.06;
  letter-spacing:.005em;
  color:var(--vh-mist);
}

p{margin:0 0 1em;}
p:last-child{margin-bottom:0;}

a{color:var(--vh-cyan);text-decoration-thickness:1px;text-underline-offset:3px;}
a:hover{color:#7CF3EC;}

img,svg,video{display:block;max-width:100%;height:auto;}

ul,ol{margin:0 0 1em;padding-left:1.15em;}

button{font:inherit;color:inherit;}

hr{border:0;border-top:1px solid var(--vh-line);margin:2rem 0;}

:focus-visible{
  outline:2px solid var(--vh-cyan);
  outline-offset:3px;
  border-radius:2px;
}

::selection{background:var(--vh-cyan);color:var(--vh-ink);}

/* ---------- 工具类 ---------- */
.vh-sr-only{
  position:absolute;
  width:1px;height:1px;
  padding:0;margin:-1px;
  overflow:hidden;
  clip:rect(0 0 0 0);
  clip-path:inset(50%);
  white-space:nowrap;
  border:0;
}

.vh-skip{
  position:fixed;
  top:.6rem;left:.6rem;
  z-index:300;
  padding:.62rem 1rem;
  background:var(--vh-cyan);
  color:var(--vh-ink);
  font-family:var(--vh-font-body);
  font-size:.85rem;
  font-weight:700;
  letter-spacing:.04em;
  text-decoration:none;
  border-radius:2px;
  transform:translateY(-180%);
  transition:transform .2s var(--vh-ease);
}
.vh-skip:focus,
.vh-skip:focus-visible{transform:none;color:var(--vh-ink);}

.vh-divider{
  height:1px;
  border:0;
  margin:clamp(1.5rem,4vw,3rem) 0;
  background:linear-gradient(90deg,var(--vh-line-strong),transparent 72%);
}

/* ---------- 头 部 ---------- */
.vh-header{
  position:fixed;
  top:0;left:0;bottom:0;
  width:var(--vh-rail);
  z-index:80;
  background:
    linear-gradient(180deg,rgba(3,11,26,.97) 0%,rgba(8,27,58,.97) 62%,rgba(3,11,26,.99) 100%);
  border-right:1px solid var(--vh-line);
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
}
.vh-header::after{
  content:"";
  position:absolute;
  top:0;right:-1px;
  width:1px;height:38%;
  background:linear-gradient(180deg,var(--vh-cyan),transparent);
  opacity:.55;
  pointer-events:none;
}

.vh-rail{
  display:flex;
  flex-direction:column;
  height:100%;
  padding:clamp(1rem,2.2vw,1.7rem) clamp(.85rem,1.8vw,1.35rem);
  overflow-y:auto;
  scrollbar-width:thin;
  scrollbar-color:rgba(143,163,199,.35) transparent;
}

.vh-rail__top{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:.75rem;
  flex:0 0 auto;
}

.vh-brand{
  display:flex;
  align-items:center;
  gap:.7rem;
  min-width:0;
  text-decoration:none;
  color:var(--vh-mist);
}
.vh-brand:hover{color:var(--vh-mist);}

.vh-brand__mark{
  flex:0 0 auto;
  width:40px;height:40px;
  display:grid;
  place-items:center;
  font-family:var(--vh-font-mono);
  font-size:.92rem;
  font-weight:700;
  letter-spacing:.03em;
  color:#04121F;
  background:linear-gradient(135deg,var(--vh-cyan) 0%,var(--vh-teal) 100%);
  clip-path:polygon(0 0,100% 0,100% 70%,70% 100%,0 100%);
  box-shadow:0 0 22px -8px rgba(38,224,214,.85);
}

.vh-brand__text{
  display:flex;
  flex-direction:column;
  min-width:0;
}

.vh-brand__name{
  font-family:var(--vh-font-display);
  font-weight:900;
  font-size:1.16rem;
  line-height:1.1;
  letter-spacing:.06em;
  color:var(--vh-mist);
}

.vh-brand__sub{
  margin-top:.16rem;
  font-family:var(--vh-font-mono);
  font-size:.64rem;
  line-height:1.35;
  letter-spacing:.06em;
  color:var(--vh-steel);
}

.vh-navtoggle{
  display:none;
  align-items:center;
  gap:.5rem;
  padding:.42rem .68rem;
  background:rgba(38,224,214,.08);
  border:1px solid rgba(38,224,214,.42);
  border-radius:2px;
  color:var(--vh-cyan);
  font-family:var(--vh-font-mono);
  font-size:.7rem;
  letter-spacing:.14em;
  cursor:pointer;
  transition:background-color .18s var(--vh-ease),border-color .18s var(--vh-ease);
}
.vh-navtoggle:hover{background:rgba(38,224,214,.16);border-color:var(--vh-cyan);}

.vh-navtoggle__bars{
  display:grid;
  gap:4px;
  width:16px;
}
.vh-navtoggle__bars i{
  display:block;
  height:1.5px;
  background:currentColor;
  transition:transform .22s var(--vh-ease),opacity .22s var(--vh-ease);
}
.vh-header[data-open="true"] .vh-navtoggle__bars i:first-child{transform:translateY(2.75px) rotate(45deg);}
.vh-header[data-open="true"] .vh-navtoggle__bars i:last-child{transform:translateY(-2.75px) rotate(-45deg);}

.vh-navtoggle__label{line-height:1;}

.vh-nav{
  display:flex;
  flex-direction:column;
  flex:1 1 auto;
  min-height:0;
  margin-top:clamp(.9rem,2.4vw,1.6rem);
}

.vh-nav__list{
  list-style:none;
  margin:0;
  padding:0;
  display:flex;
  flex-direction:column;
  gap:2px;
}

.vh-nav__item{margin:0;}

.vh-nav__link{
  position:relative;
  display:flex;
  align-items:baseline;
  gap:.55rem;
  padding:.5rem .6rem .5rem 1.15rem;
  border-radius:2px;
  font-size:.92rem;
  font-weight:500;
  letter-spacing:.05em;
  color:var(--vh-steel);
  text-decoration:none;
  transition:color .18s var(--vh-ease),background-color .18s var(--vh-ease),box-shadow .18s var(--vh-ease);
}
.vh-nav__link::before{
  content:"";
  position:absolute;
  left:0;top:50%;
  width:2px;height:12px;
  transform:translateY(-50%);
  background:var(--vh-steel);
  opacity:.35;
  transition:height .2s var(--vh-ease),background-color .2s var(--vh-ease),opacity .2s var(--vh-ease),box-shadow .2s var(--vh-ease);
}
.vh-nav__link:hover{
  color:var(--vh-mist);
  background:rgba(38,224,214,.07);
}
.vh-nav__link:hover::before{
  height:20px;
  background:var(--vh-cyan);
  opacity:1;
}
.vh-nav__link[aria-current="page"]{
  color:var(--vh-cyan);
  background:rgba(38,224,214,.1);
  box-shadow:inset 0 0 0 1px rgba(38,224,214,.36);
}
.vh-nav__link[aria-current="page"]::before{
  height:24px;
  background:var(--vh-cyan);
  opacity:1;
  box-shadow:0 0 12px var(--vh-cyan);
}

.vh-nav__idx{
  flex:0 0 auto;
  font-family:var(--vh-font-mono);
  font-size:.64rem;
  font-weight:400;
  letter-spacing:.1em;
  color:var(--vh-steel);
  opacity:.85;
  transition:color .18s var(--vh-ease);
}
.vh-nav__link:hover .vh-nav__idx{color:var(--vh-mist);}
.vh-nav__link[aria-current="page"] .vh-nav__idx{color:var(--vh-cyan);opacity:1;}

.vh-nav__label{flex:1 1 auto;}

.vh-nav__foot{
  margin-top:auto;
  padding-top:clamp(.9rem,2.4vw,1.4rem);
  border-top:1px solid var(--vh-line);
  display:flex;
  flex-direction:column;
  gap:.75rem;
}

.vh-nav__status{
  display:flex;
  align-items:flex-start;
  gap:.45rem;
  margin:0;
  font-family:var(--vh-font-mono);
  font-size:.66rem;
  line-height:1.55;
  letter-spacing:.03em;
  color:var(--vh-steel);
}

.vh-dot{
  flex:0 0 auto;
  width:6px;height:6px;
  margin-top:.34rem;
  border-radius:50%;
  background:var(--vh-ok);
  box-shadow:0 0 0 3px rgba(79,209,139,.16);
  animation:vh-pulse 2.6s ease-in-out infinite;
}

@keyframes vh-pulse{
  0%,100%{box-shadow:0 0 0 3px rgba(79,209,139,.16);}
  50%{box-shadow:0 0 0 6px rgba(79,209,139,.04);}
}

/* ---------- 按钮 ---------- */
.vh-cta,
.vh-btn{
  position:relative;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.45rem;
  padding:.7rem 1.1rem;
  font-family:var(--vh-font-body);
  font-size:.88rem;
  font-weight:700;
  letter-spacing:.04em;
  line-height:1.2;
  text-align:center;
  text-decoration:none;
  color:#08121F;
  background:linear-gradient(135deg,var(--vh-orange) 0%,#F0661A 100%);
  border:1px solid transparent;
  border-radius:2px;
  cursor:pointer;
  clip-path:polygon(0 0,100% 0,100% calc(100% - 9px),calc(100% - 9px) 100%,0 100%);
  transition:transform .18s var(--vh-ease),filter .18s var(--vh-ease),box-shadow .18s var(--vh-ease);
}
.vh-cta:hover,
.vh-btn:hover{
  color:#08121F;
  transform:translateY(-1px);
  filter:brightness(1.07);
  box-shadow:0 16px 32px -20px rgba(255,138,61,.95);
}
.vh-cta:active,
.vh-btn:active{transform:translateY(0);}
.vh-cta:focus-visible,
.vh-btn:focus-visible{
  outline:none;
  box-shadow:inset 0 0 0 2px #08121F,inset 0 0 0 4px var(--vh-mist);
}

.vh-cta--sm,
.vh-btn--sm{
  align-self:stretch;
  padding:.55rem .8rem;
  font-size:.78rem;
}

.vh-cta--ghost,
.vh-btn--ghost{
  color:var(--vh-cyan);
  background:transparent;
  border-color:rgba(38,224,214,.5);
  clip-path:none;
}
.vh-cta--ghost:hover,
.vh-btn--ghost:hover{
  color:var(--vh-mist);
  background:rgba(38,224,214,.12);
  border-color:var(--vh-cyan);
  box-shadow:none;
}

/* ---------- 通用版式 ---------- */
.vh-main{
  position:relative;
  z-index:1;
  display:block;
}

.vh-container{
  width:100%;
  max-width:var(--vh-max);
  margin-inline:auto;
  padding-inline:var(--vh-gutter);
}

.vh-section{
  padding-block:clamp(2.4rem,6vw,5rem);
}

.vh-eyebrow{
  display:block;
  margin:0 0 .85rem;
  font-family:var(--vh-font-mono);
  font-size:.7rem;
  font-weight:400;
  letter-spacing:.26em;
  text-transform:uppercase;
  color:var(--vh-cyan);
}

.vh-title{
  margin:0 0 .35em;
  font-family:var(--vh-font-display);
  font-weight:900;
  font-size:clamp(2.8rem,6vw,6.4rem);
  line-height:.92;
  letter-spacing:-.005em;
  color:var(--vh-mist);
}

.vh-title--md{
  font-size:clamp(1.8rem,3vw,3rem);
  line-height:1.03;
}

.vh-lead{
  max-width:56ch;
  margin:0 0 1.2em;
  font-size:clamp(1rem,1.3vw,1.15rem);
  line-height:1.72;
  color:rgba(234,242,255,.82);
}

.vh-prose{
  max-width:68ch;
  font-size:clamp(15px,1vw,17px);
  line-height:1.78;
  color:rgba(234,242,255,.86);
}
.vh-prose h2{
  margin:2.2em 0 .6em;
  font-size:clamp(1.5rem,2.4vw,2.1rem);
  color:var(--vh-mist);
}
.vh-prose h3{
  margin:1.8em 0 .5em;
  font-size:clamp(1.15rem,1.7vw,1.4rem);
  color:var(--vh-mist);
}
.vh-prose a{color:var(--vh-cyan);}
.vh-prose ul,
.vh-prose ol{padding-left:1.25em;}
.vh-prose li{margin-bottom:.4em;}
.vh-prose strong{color:var(--vh-mist);font-weight:700;}

/* ---------- 面包屑 ---------- */
.vh-breadcrumb{
  padding-block:.9rem;
  border-bottom:1px solid var(--vh-line);
  font-family:var(--vh-font-mono);
  font-size:.7rem;
  letter-spacing:.08em;
  color:var(--vh-steel);
}
.vh-breadcrumb__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:.45rem;
  list-style:none;
  margin:0;
  padding:0;
}
.vh-breadcrumb__item{
  display:inline-flex;
  align-items:center;
  gap:.45rem;
  color:var(--vh-steel);
}
.vh-breadcrumb__item + .vh-breadcrumb__item::before{
  content:"/";
  color:rgba(143,163,199,.5);
}
.vh-breadcrumb__item[aria-current="page"]{color:var(--vh-mist);}
.vh-breadcrumb__link{
  color:var(--vh-steel);
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .18s var(--vh-ease),border-color .18s var(--vh-ease);
}
.vh-breadcrumb__link:hover{
  color:var(--vh-cyan);
  border-bottom-color:var(--vh-cyan);
}

/* ---------- 网格与卡片 ---------- */
.vh-grid{
  display:grid;
  gap:clamp(1rem,2.2vw,1.75rem);
  grid-template-columns:minmax(0,1fr);
}
.vh-grid--2{grid-template-columns:repeat(2,minmax(0,1fr));}
.vh-grid--3{grid-template-columns:repeat(3,minmax(0,1fr));}
.vh-grid--offset > *:nth-child(even){transform:translateY(clamp(.75rem,2vw,2rem));}

.vh-card{
  position:relative;
  padding:clamp(1rem,2vw,1.6rem);
  background:linear-gradient(158deg,rgba(11,36,69,.94) 0%,rgba(8,27,58,.58) 100%);
  border:1px solid var(--vh-line);
  border-radius:var(--vh-radius);
  box-shadow:0 24px 44px -34px rgba(0,0,0,.95);
  transition:border-color .22s var(--vh-ease),transform .22s var(--vh-ease),box-shadow .22s var(--vh-ease);
}
.vh-card:hover{
  border-color:rgba(38,224,214,.5);
  transform:translateY(-2px);
  box-shadow:0 26px 46px -30px rgba(38,224,214,.35);
}
.vh-card--accent{
  background:linear-gradient(158deg,rgba(58,30,110,.86) 0%,rgba(8,27,58,.62) 100%);
  border-color:rgba(255,138,61,.34);
}
.vh-card--accent:hover{
  border-color:rgba(255,138,61,.68);
  box-shadow:0 26px 46px -30px rgba(255,138,61,.42);
}
.vh-card__title{
  margin:0 0 .45em;
  font-family:var(--vh-font-display);
  font-weight:800;
  font-size:clamp(1.1rem,1.6vw,1.35rem);
  line-height:1.15;
  color:var(--vh-mist);
}
.vh-card__text{
  margin:0;
  font-size:.94rem;
  line-height:1.7;
  color:rgba(234,242,255,.78);
}

.vh-stat{display:grid;gap:.28rem;}
.vh-stat__num{
  font-family:var(--vh-font-mono);
  font-weight:700;
  font-size:clamp(1.5rem,3vw,2.2rem);
  line-height:1;
  letter-spacing:-.01em;
  color:var(--vh-orange);
  white-space:nowrap;
}
.vh-stat__label{
  font-family:var(--vh-font-mono);
  font-size:.66rem;
  font-weight:400;
  letter-spacing:.15em;
  text-transform:uppercase;
  color:var(--vh-steel);
}

.vh-tag{
  display:inline-flex;
  align-items:center;
  gap:.35rem;
  padding:.22rem .55rem;
  font-family:var(--vh-font-mono);
  font-size:.65rem;
  letter-spacing:.1em;
  text-transform:uppercase;
  color:var(--vh-cyan);
  background:rgba(38,224,214,.1);
  border:1px solid rgba(38,224,214,.32);
  border-radius:2px;
}
.vh-tag--warm{
  color:var(--vh-orange);
  background:rgba(255,138,61,.1);
  border-color:rgba(255,138,61,.34);
}

/* ---------- 响应式图片容器 ---------- */
.vh-media{
  position:relative;
  display:block;
  width:100%;
  aspect-ratio:16 / 10;
  overflow:hidden;
  border:1px solid var(--vh-line);
  border-radius:var(--vh-radius);
  background:
    linear-gradient(140deg,#0B2445 0%,var(--vh-violet) 58%,var(--vh-teal) 100%);
  isolation:isolate;
}
.vh-media > img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.vh-media::after{
  content:"";
  position:absolute;
  inset:0;
  background:repeating-linear-gradient(180deg,rgba(234,242,255,.055) 0 1px,transparent 1px 4px);
  opacity:.55;
  pointer-events:none;
}
.vh-media--wide{aspect-ratio:21 / 9;}
.vh-media--tall{aspect-ratio:4 / 5;}
.vh-media--square{aspect-ratio:1 / 1;}

/* ---------- 页 脚 ---------- */
.vh-footer{
  position:relative;
  z-index:1;
  overflow:hidden;
  padding:clamp(2.4rem,6vw,4.5rem) var(--vh-gutter) clamp(1.25rem,3vw,2rem);
  background:var(--vh-ink);
  border-top:1px solid var(--vh-line);
  color:var(--vh-mist);
}
.vh-footer::before{
  content:"";
  position:absolute;
  inset:0 0 auto 0;
  height:1px;
  background:linear-gradient(90deg,transparent,var(--vh-cyan) 22%,var(--vh-orange) 78%,transparent);
  opacity:.75;
  pointer-events:none;
}
.vh-footer::after{
  content:"";
  position:absolute;
  top:-42%;right:-14%;
  width:54vw;height:54vw;
  max-width:600px;max-height:600px;
  background:radial-gradient(circle at 34% 34%,rgba(58,30,110,.6),transparent 70%);
  pointer-events:none;
}

.vh-footer__grid{
  position:relative;
  z-index:1;
  display:grid;
  gap:clamp(1.6rem,4vw,3rem);
  grid-template-columns:minmax(0,1.5fr) minmax(0,.7fr) minmax(0,.95fr);
  max-width:var(--vh-max);
  margin-inline:auto;
  align-items:start;
}
.vh-footer__grid > *:nth-child(2){margin-top:clamp(0rem,1.2vw,.85rem);}
.vh-footer__grid > *:nth-child(3){margin-top:clamp(0rem,2.4vw,1.7rem);}

.vh-footer__brand{min-width:0;}

.vh-footer__wordmark{
  margin:0 0 .55rem;
  font-family:var(--vh-font-display);
  font-weight:900;
  font-size:clamp(2.2rem,5vw,3.6rem);
  line-height:.9;
  letter-spacing:.02em;
  color:var(--vh-mist);
  background:linear-gradient(102deg,var(--vh-mist) 0%,rgba(38,224,214,.72) 100%);
  -webkit-background-clip:text;
  background-clip:text;
  -webkit-text-fill-color:transparent;
}

.vh-footer__tagline{
  max-width:34ch;
  margin:0;
  font-size:.94rem;
  line-height:1.7;
  color:var(--vh-steel);
}

.vh-footer__col{min-width:0;}

.vh-footer__title{
  margin:0 0 .55rem;
  font-family:var(--vh-font-mono);
  font-size:.66rem;
  font-weight:400;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--vh-cyan);
}
.vh-footer__title--sub{margin-top:1.1rem;color:var(--vh-steel);}

.vh-footer__list{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:.42rem;
}

.vh-footer__link{
  display:inline-block;
  font-size:.9rem;
  color:var(--vh-steel);
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .18s var(--vh-ease),border-color .18s var(--vh-ease);
}
.vh-footer__link:hover{
  color:var(--vh-cyan);
  border-bottom-color:var(--vh-cyan);
}

.vh-contact-list{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:.7rem;
}
.vh-contact-list__k{
  display:block;
  font-family:var(--vh-font-mono);
  font-size:.63rem;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--vh-steel);
}
.vh-contact-list__v{
  display:block;
  margin-top:.12rem;
  font-family:var(--vh-font-mono);
  font-size:.86rem;
  line-height:1.5;
  letter-spacing:.01em;
  color:var(--vh-mist);
  overflow-wrap:anywhere;
}

.vh-footer__note{
  margin:1rem 0 0;
  max-width:36ch;
  font-size:.74rem;
  line-height:1.65;
  color:rgba(143,163,199,.86);
}

.vh-footer__base{
  position:relative;
  z-index:1;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:.75rem 1.5rem;
  max-width:var(--vh-max);
  margin:clamp(1.8rem,4vw,2.8rem) auto 0;
  padding-top:1.1rem;
  border-top:1px solid var(--vh-line);
  font-family:var(--vh-font-mono);
  font-size:.7rem;
  letter-spacing:.06em;
  color:var(--vh-steel);
}

.vh-footer__legal{
  display:flex;
  flex-wrap:wrap;
  gap:.35rem 1.15rem;
  list-style:none;
  margin:0;
  padding:0;
}
.vh-footer__legal .vh-footer__link{font-size:.72rem;}

.vh-footer__meta{
  margin:0;
  font-size:.7rem;
  letter-spacing:.06em;
  color:rgba(143,163,199,.8);
}

/* ---------- 滚动进度 / 返回顶部 ---------- */
.vh-progress{
  position:fixed;
  top:0;left:0;
  width:2px;height:100vh;
  z-index:95;
  pointer-events:none;
  background:rgba(143,163,199,.1);
}
.vh-progress__bar{
  display:block;
  width:100%;
  height:0;
  background:linear-gradient(180deg,var(--vh-cyan) 0%,var(--vh-orange) 100%);
  box-shadow:0 0 14px rgba(38,224,214,.8);
  will-change:height;
}

.vh-top{
  position:fixed;
  right:clamp(1rem,3vw,2.25rem);
  bottom:clamp(1rem,3vw,2.25rem);
  z-index:96;
  display:inline-flex;
  align-items:center;
  gap:.4rem;
  padding:.5rem .72rem;
  font-family:var(--vh-font-mono);
  font-size:.64rem;
  letter-spacing:.14em;
  color:var(--vh-mist);
  background:rgba(3,11,26,.86);
  border:1px solid var(--vh-line-strong);
  border-radius:2px;
  cursor:pointer;
  opacity:0;
  visibility:hidden;
  transform:translateY(8px);
  backdrop-filter:blur(6px);
  -webkit-backdrop-filter:blur(6px);
  transition:opacity .22s var(--vh-ease),transform .22s var(--vh-ease),visibility .22s,border-color .2s var(--vh-ease),color .2s var(--vh-ease);
}
.vh-top.is-shown{
  opacity:1;
  visibility:visible;
  transform:none;
}
.vh-top:hover{
  color:var(--vh-cyan);
  border-color:var(--vh-cyan);
}
.vh-top__label{line-height:1;}

/* ---------- 入场 ---------- */
.vh-js [data-reveal]{
  opacity:0;
  transform:translateY(14px);
  transition:opacity .55s var(--vh-ease),transform .55s var(--vh-ease);
  transition-delay:var(--vh-delay,0ms);
}
.vh-js [data-reveal].is-revealed{
  opacity:1;
  transform:none;
}

/* ---------- 平板 ---------- */
@media (min-width:1024px) and (max-width:1280px){
  :root{--vh-rail:238px;}
}

/* ---------- 移动 / 窄平板 ---------- */
@media (max-width:1023px){
  :root{--vh-rail:0px;}

  body{
    padding-left:0;
    background-attachment:scroll;
  }

  .vh-header{
    position:sticky;
    top:0;
    left:auto;
    bottom:auto;
    width:100%;
    border-right:0;
    border-bottom:1px solid var(--vh-line);
  }
  .vh-header::after{display:none;}

  .vh-rail{
    height:auto;
    overflow:visible;
    padding:.58rem var(--vh-gutter);
  }

  .vh-rail__top{
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:1rem;
  }

  .vh-brand__sub{display:none;}
  .vh-navtoggle{display:inline-flex;}

  .vh-nav{
    position:absolute;
    top:100%;left:0;right:0;
    display:none;
    flex-direction:column;
    margin-top:0;
    padding:.3rem var(--vh-gutter) 1.1rem;
    background:linear-gradient(180deg,#06122A 0%,var(--vh-ink) 100%);
    border-bottom:1px solid var(--vh-line);
    box-shadow:0 34px 64px -34px rgba(0,0,0,.96);
    max-height:78vh;
    overflow-y:auto;
  }
  .vh-header[data-open="true"] .vh-nav{display:flex;}

  .vh-nav__list{gap:1px;}

  .vh-nav__link{
    padding:.72rem .85rem .72rem 1.15rem;
    font-size:.95rem;
  }

  .vh-nav__foot{
    margin-top:.9rem;
    padding-top:.9rem;
    display:flex;
    flex-direction:column;
    gap:.7rem;
  }
  .vh-cta--sm,
  .vh-btn--sm{align-self:flex-start;}

  .vh-grid--2,
  .vh-grid--3{grid-template-columns:minmax(0,1fr);}
  .vh-grid--offset > *:nth-child(even){transform:none;}

  .vh-footer__grid{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }
  .vh-footer__brand{grid-column:1 / -1;}
  .vh-footer__grid > *:nth-child(2){margin-top:0;}
  .vh-footer__grid > *:nth-child(3){margin-top:0;}
}

@media (max-width:640px){
  body{font-size:15px;}

  .vh-title{font-size:clamp(2.2rem,9vw,3rem);line-height:.96;}
  .vh-title--md{font-size:clamp(1.5rem,6vw,2rem);}

  .vh-footer__grid{grid-template-columns:minmax(0,1fr);}
  .vh-footer__base{flex-direction:column;align-items:flex-start;}
  .vh-top{right:.85rem;bottom:.85rem;padding:.44rem .62rem;}
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    animation-duration:.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.01ms !important;
    scroll-behavior:auto !important;
  }
  .vh-dot{animation:none;}
  .vh-js [data-reveal]{
    opacity:1;
    transform:none;
    transition:none;
  }
  .vh-top{transition:none;}
}