/* =========================================================
   聚星主页 · /assets/site.css
   深空星轨体系：深空黑蓝基底 + 星云紫氛围 + 亮橙锚点 + 荧光青索引
   ========================================================= */

/* ---------- 0. 设计变量 ---------- */
:root{
  --ink-0:#05081C;
  --ink-1:#0B1233;
  --ink-2:#241A4D;
  --nebula:#5B3FD1;
  --nebula-bright:#8C7BFF;
  --orange:#FF6A2B;
  --cyan:#2EE6C8;
  --paper:#F3F0E8;
  --dust:#A7A2B8;
  --line:rgba(243,240,232,.14);
  --line-soft:rgba(243,240,232,.08);
  --glass:rgba(36,26,77,.42);

  --font-head:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,"Noto Sans Mono",monospace;

  --wrap:1180px;
  --pad:clamp(18px,4vw,44px);
  --ease:cubic-bezier(.22,.61,.36,1);
  --t:220ms;
}

/* ---------- 1. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{
  overflow-x:clip;
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
}
body,h1,h2,h3,h4,h5,p,ul,ol,li,figure,figcaption,blockquote,dl,dd{margin:0;padding:0}
ul,ol{list-style:none}
img,svg,video{display:block;max-width:100%;height:auto}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
a{color:var(--nebula-bright);text-decoration:none}
a:hover{color:var(--cyan)}
::selection{background:var(--orange);color:#08040F}

/* ---------- 2. 基础排版 ---------- */
body{
  min-height:100vh;
  background-color:var(--ink-0);
  background-image:
    radial-gradient(70rem 46rem at 84% -10%, rgba(91,63,209,.34), transparent 62%),
    radial-gradient(52rem 40rem at 2% 8%, rgba(46,230,200,.10), transparent 68%),
    radial-gradient(46rem 44rem at 50% 112%, rgba(255,106,43,.10), transparent 70%);
  background-repeat:no-repeat;
  color:var(--paper);
  font-family:var(--font-body);
  font-size:clamp(16px,1.02vw,17px);
  line-height:1.85;
  font-weight:400;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4,h5{
  font-family:var(--font-head);
  font-weight:900;
  line-height:1.14;
  letter-spacing:-.01em;
  color:var(--paper);
  text-wrap:balance;
}
p{text-wrap:pretty}
:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:3px;
  border-radius:2px;
}

/* ---------- 3. 工具类 ---------- */
.wrap{
  width:100%;
  max-width:var(--wrap);
  margin-inline:auto;
  padding-inline:var(--pad);
}
.mono{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  letter-spacing:.08em;
}
.visually-hidden{
  position:absolute!important;
  width:1px;height:1px;
  margin:-1px;padding:0;
  overflow:hidden;
  clip:rect(0 0 0 0);
  clip-path:inset(50%);
  white-space:nowrap;
  border:0;
}
.skip-link{
  position:fixed;
  top:10px;left:10px;
  z-index:200;
  transform:translateY(-180%);
  background:var(--orange);
  color:#0A0512;
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.1em;
  padding:10px 18px;
  border-radius:2px;
  transition:transform 180ms var(--ease);
}
.skip-link:focus{transform:translateY(0);color:#0A0512}

/* ---------- 4. 站点头部 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:80;
  background:linear-gradient(180deg,rgba(5,8,28,.97),rgba(5,8,28,.88));
  border-bottom:1px solid var(--line-soft);
  -webkit-backdrop-filter:blur(18px) saturate(135%);
  backdrop-filter:blur(18px) saturate(135%);
  transition:box-shadow var(--t) var(--ease);
}
.site-header[data-scrolled="true"]{
  box-shadow:0 24px 48px -34px rgba(0,0,0,.95), inset 0 -1px 0 rgba(140,123,255,.22);
}

/* 阅读进度 */
.progress{
  position:relative;
  display:block;
  height:2px;
  background:rgba(243,240,232,.07);
  overflow:hidden;
}
.progress__fill{
  display:block;
  height:100%;
  width:0;
  background:linear-gradient(90deg,var(--cyan),var(--nebula-bright));
  box-shadow:0 0 14px rgba(46,230,200,.7);
  transition:width 120ms linear;
}

/* 星尘信号条 */
.signal-bar{
  border-bottom:1px solid var(--line-soft);
  background-image:
    radial-gradient(1.2px 1.2px at 8% 42%, rgba(243,240,232,.65), transparent 55%),
    radial-gradient(1px 1px at 24% 72%, rgba(46,230,200,.6), transparent 55%),
    radial-gradient(1.4px 1.4px at 47% 28%, rgba(243,240,232,.45), transparent 55%),
    radial-gradient(1px 1px at 66% 76%, rgba(140,123,255,.65), transparent 55%),
    radial-gradient(1.3px 1.3px at 86% 34%, rgba(243,240,232,.5), transparent 55%);
  background-size:220px 100%,180px 100%,260px 100%,200px 100%,240px 100%;
  background-repeat:repeat-x;
}
.signal-bar__inner{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:8px 18px;
  padding-block:7px;
}
.signal-bar__id{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.18em;
  color:var(--dust);
  text-transform:uppercase;
}
.signal-bar__links{
  display:flex;
  flex-wrap:wrap;
  gap:16px;
}
.signal-link{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  color:var(--dust);
  padding-bottom:2px;
  border-bottom:1px solid transparent;
  transition:color var(--t) var(--ease),border-color var(--t) var(--ease);
}
.signal-link:hover,
.signal-link:focus-visible{
  color:var(--cyan);
  border-bottom-color:var(--cyan);
}

/* 刊头题签 */
.masthead__inner{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);
  align-items:center;
  gap:clamp(12px,2vw,28px);
  padding-block:14px;
}
.masthead__meta{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  color:var(--dust);
  text-transform:uppercase;
}
.brand{
  display:inline-flex;
  flex-direction:column;
  align-items:center;
  gap:3px;
  justify-self:center;
  text-align:center;
  color:var(--paper);
}
.brand:hover{color:var(--paper)}
.brand__name{
  font-family:var(--font-head);
  font-weight:900;
  font-size:clamp(24px,3vw,36px);
  line-height:1.05;
  letter-spacing:.1em;
}
.brand__tagline{
  display:inline-flex;
  align-items:center;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.4em;
  color:var(--dust);
  transition:color var(--t) var(--ease);
}
.brand__tagline::before{
  content:"✦";
  margin-right:.7em;
  font-size:.9em;
  color:var(--orange);
  letter-spacing:0;
}
.brand:hover .brand__tagline{color:var(--cyan)}
.masthead__actions{
  display:flex;
  align-items:center;
  gap:10px;
  justify-self:end;
}

/* 移动端栏目按钮 */
.nav-toggle{
  display:none;
  align-items:center;
  gap:9px;
  padding:9px 13px;
  border:1px solid rgba(243,240,232,.28);
  border-radius:2px;
  color:var(--paper);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.18em;
  transition:border-color var(--t) var(--ease),color var(--t) var(--ease),background-color var(--t) var(--ease);
}
.nav-toggle:hover{border-color:var(--nebula-bright);color:var(--nebula-bright)}
.nav-toggle[aria-expanded="true"]{
  border-color:var(--orange);
  color:var(--orange);
  background:rgba(255,106,43,.1);
}
.nav-toggle__bars{
  position:relative;
  display:block;
  width:16px;height:2px;
  background:currentColor;
  transition:background-color 160ms var(--ease);
}
.nav-toggle__bars::before,
.nav-toggle__bars::after{
  content:"";
  position:absolute;left:0;
  width:16px;height:2px;
  background:currentColor;
  transition:transform 180ms var(--ease);
}
.nav-toggle__bars::before{top:-5px}
.nav-toggle__bars::after{top:5px}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars{background:transparent}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before{transform:translateY(5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after{transform:translateY(-5px) rotate(-45deg)}
.nav-toggle__text{line-height:1}

/* 主导航 */
.site-nav{
  display:block;
  background:rgba(11,18,51,.5);
  border-top:1px solid var(--line-soft);
  border-bottom:1px solid var(--line);
}
.site-nav__list{
  counter-reset:nav;
  display:flex;
  flex-wrap:wrap;
  justify-content:center;
  gap:clamp(10px,2.2vw,32px);
  padding-block:11px;
}
.site-nav__list > li{
  counter-increment:nav;
  display:flex;
}
.site-nav__link{
  position:relative;
  display:inline-flex;
  align-items:baseline;
  gap:.5em;
  padding:5px 2px;
  color:rgba(243,240,232,.82);
  font-size:15px;
  letter-spacing:.06em;
  transition:color var(--t) var(--ease);
}
.site-nav__link::before{
  content:counter(nav,decimal-leading-zero);
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.04em;
  color:var(--cyan);
  opacity:.65;
  transition:color var(--t) var(--ease),opacity var(--t) var(--ease);
}
.site-nav__link::after{
  content:"";
  position:absolute;
  left:0;right:100%;bottom:0;
  height:1px;
  background:var(--orange);
  transition:right 240ms var(--ease);
}
.site-nav__link:hover{color:var(--paper)}
.site-nav__link:hover::after{right:0}
.site-nav__link[aria-current="page"]{
  color:var(--paper);
  font-weight:700;
}
.site-nav__link[aria-current="page"]::before{
  color:var(--orange);
  opacity:1;
}
.site-nav__link[aria-current="page"]::after{
  right:0;
  background:var(--orange);
  box-shadow:0 0 10px rgba(255,106,43,.75);
}

/* ---------- 5. 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.5em;
  padding:.66em 1.15em;
  border:1px solid var(--line);
  border-radius:2px;
  background:transparent;
  color:var(--paper);
  font-family:var(--font-mono);
  font-size:12.5px;
  font-weight:500;
  letter-spacing:.12em;
  line-height:1.3;
  text-align:center;
  transition:color var(--t) var(--ease),border-color var(--t) var(--ease),
             background-color var(--t) var(--ease),box-shadow var(--t) var(--ease),
             transform var(--t) var(--ease);
}
.btn:hover{transform:translateY(-2px)}
.btn--primary{
  background:var(--orange);
  border-color:var(--orange);
  color:#0A0512;
  font-weight:700;
}
.btn--primary:hover{
  color:#0A0512;
  box-shadow:0 0 0 1px rgba(255,106,43,.45),0 16px 32px -16px rgba(255,106,43,.9);
}
.btn--ghost{
  border-color:rgba(243,240,232,.3);
  color:var(--paper);
}
.btn--ghost:hover{
  border-color:var(--nebula-bright);
  color:var(--nebula-bright);
  background:rgba(140,123,255,.08);
}

/* ---------- 6. 站点页脚 ---------- */
.site-footer{
  position:relative;
  isolation:isolate;
  margin-top:clamp(56px,9vw,130px);
  border-top:1px solid rgba(140,123,255,.28);
  background:linear-gradient(180deg,rgba(11,18,51,.92),rgba(5,8,28,.98) 62%);
  overflow:hidden;
}
.site-footer::before{
  content:"";
  position:absolute;
  inset:-55% 40% auto -25%;
  height:440px;
  z-index:0;
  pointer-events:none;
  background:radial-gradient(closest-side,rgba(91,63,209,.38),transparent 72%);
}
.site-footer > .wrap{position:relative;z-index:1}

.footer-top{
  display:grid;
  grid-template-columns:1.45fr repeat(4,minmax(0,1fr));
  gap:clamp(24px,3.6vw,48px);
  padding-block:clamp(40px,6vw,78px) clamp(26px,4vw,46px);
}
.footer-brand{
  display:flex;
  flex-direction:column;
  align-items:flex-start;
  gap:12px;
}
.footer-brand__name{
  font-family:var(--font-head);
  font-weight:900;
  font-size:clamp(20px,2.3vw,27px);
  line-height:1.25;
  letter-spacing:.02em;
  color:var(--paper);
}
.footer-brand__note{
  max-width:30ch;
  font-size:13.5px;
  line-height:1.8;
  color:var(--dust);
}
.footer-brand__cta{margin-top:6px}

.footer-col{
  display:flex;
  flex-direction:column;
  gap:10px;
  min-width:0;
}
.footer-col__title{
  font-family:var(--font-mono);
  font-size:11.5px;
  font-weight:600;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--paper);
  padding-bottom:10px;
  border-bottom:1px solid var(--line-soft);
}
.footer-col__note{
  font-size:12px;
  line-height:1.7;
  color:var(--dust);
}
.footer-col__list{
  display:flex;
  flex-direction:column;
  gap:2px;
}
.footer-link{
  display:inline-block;
  padding-block:5px;
  font-size:14px;
  color:var(--dust);
  transition:color var(--t) var(--ease),transform var(--t) var(--ease);
}
.footer-link:hover,
.footer-link:focus-visible{
  color:var(--paper);
  transform:translateX(3px);
}
.footer-col--screen{
  padding-left:clamp(14px,1.8vw,22px);
  border-left:1px solid rgba(46,230,200,.4);
  background:linear-gradient(180deg,rgba(46,230,200,.07),transparent 72%);
}
.footer-col--screen .footer-col__title{
  color:var(--cyan);
  border-bottom-color:rgba(46,230,200,.32);
}
.footer-col--screen .footer-col__title::before{
  content:"▚ ";
  color:var(--cyan);
  opacity:.9;
}
.footer-col--screen .footer-link:hover{color:var(--cyan)}

.footer-meta{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:8px 24px;
  padding-block:18px 26px;
  border-top:1px solid var(--line);
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.1em;
  color:var(--dust);
}
.footer-meta__contact{color:var(--paper);opacity:.85}
.footer-meta__legal{color:var(--dust)}
.footer-meta__copy{color:var(--dust)}

/* ---------- 7. 章节与文字建筑 ---------- */
.section{
  position:relative;
  padding-block:clamp(46px,7vw,100px);
}
.section__head{
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:clamp(14px,3vw,40px);
  align-items:start;
  margin-bottom:clamp(22px,3.4vw,44px);
}
.index-num{
  font-family:var(--font-mono);
  font-weight:700;
  font-size:clamp(38px,6vw,84px);
  line-height:.82;
  letter-spacing:-.03em;
  color:rgba(140,123,255,.34);
  -webkit-text-stroke:1px rgba(140,123,255,.72);
  -webkit-text-fill-color:transparent;
  font-variant-numeric:tabular-nums;
}
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:.7em;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.24em;
  text-transform:uppercase;
  color:var(--cyan);
  margin-bottom:.9em;
}
.eyebrow::before{
  content:"";
  width:22px;height:1px;
  background:var(--cyan);
  opacity:.75;
}
.title-xl{
  font-family:var(--font-head);
  font-weight:900;
  font-size:clamp(38px,7.4vw,92px);
  line-height:.98;
  letter-spacing:-.02em;
}
.lede{
  max-width:32em;
  font-size:clamp(16.5px,1.5vw,19px);
  line-height:1.9;
  color:rgba(243,240,232,.86);
}
.prose{
  max-width:34em;
  color:rgba(243,240,232,.9);
  line-height:1.9;
}
.prose p + p{margin-top:1.05em}
.prose strong{color:var(--paper);font-weight:700}
.prose em{color:var(--cyan);font-style:normal}
.prose a{
  color:var(--cyan);
  text-decoration:underline;
  text-decoration-color:rgba(46,230,200,.45);
  text-underline-offset:3px;
}
.prose a:hover{text-decoration-color:var(--cyan)}
.prose ul,
.prose ol{margin-top:.9em;display:grid;gap:.45em}
.prose ul > li{position:relative;padding-left:1.2em}
.prose ul > li::before{
  content:"";
  position:absolute;
  left:0;top:.78em;
  width:6px;height:1px;
  background:var(--orange);
}
.prose ol{list-style:decimal inside;font-variant-numeric:tabular-nums}
.prose h3{margin-top:1.6em;font-size:clamp(19px,2vw,24px)}
.prose h4{margin-top:1.4em;font-size:17px;letter-spacing:.02em}

/* ---------- 8. 栅格 / 卡片 / 玻璃层 ---------- */
.grid{
  display:grid;
  gap:clamp(16px,2.4vw,26px);
}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}

.glass{
  background:var(--glass);
  border:1px solid rgba(243,240,232,.16);
  -webkit-backdrop-filter:blur(14px) saturate(130%);
  backdrop-filter:blur(14px) saturate(130%);
  border-radius:2px;
}
.card{
  position:relative;
  padding:clamp(18px,2.4vw,28px);
  border:1px solid var(--line);
  border-radius:2px;
  background:linear-gradient(160deg,rgba(36,26,77,.36),rgba(11,18,51,.55));
  transition:transform var(--t) var(--ease),border-color var(--t) var(--ease),
             box-shadow var(--t) var(--ease);
}
.card:hover{
  transform:translateY(-3px);
  border-color:rgba(140,123,255,.55);
  box-shadow:0 22px 44px -30px rgba(91,63,209,.9);
}
.card--glass{
  background:var(--glass);
  border-color:rgba(243,240,232,.18);
  -webkit-backdrop-filter:blur(14px) saturate(130%);
  backdrop-filter:blur(14px) saturate(130%);
}
.card__title{
  font-family:var(--font-head);
  font-weight:900;
  font-size:clamp(20px,2.2vw,26px);
  line-height:1.28;
}
.card__text{
  margin-top:.6em;
  font-size:15px;
  line-height:1.8;
  color:var(--dust);
}
.card__meta{
  margin-top:1em;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--cyan);
}

/* ---------- 9. 索引 / 旁注 / 分隔 ---------- */
.tag{
  display:inline-flex;
  align-items:center;
  gap:.4em;
  padding:.26em .72em;
  border:1px solid rgba(46,230,200,.4);
  border-radius:999px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  color:var(--cyan);
  white-space:nowrap;
}
.divider{
  height:1px;
  border:0;
  margin-block:clamp(26px,4vw,52px);
  background:linear-gradient(90deg,rgba(46,230,200,.55),rgba(140,123,255,.38),transparent);
}

/* ---------- 10. 面包屑 ---------- */
.breadcrumb{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--dust);
}
.breadcrumb__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:.55em;
}
.breadcrumb__item{
  display:inline-flex;
  align-items:center;
  gap:.55em;
}
.breadcrumb__item + .breadcrumb__item::before{
  content:"/";
  color:rgba(167,162,184,.55);
}
.breadcrumb__link{
  color:var(--dust);
  transition:color var(--t) var(--ease);
}
.breadcrumb__link:hover{color:var(--cyan)}

/* ---------- 11. 图像容器（页面阶段放占位图） ---------- */
.figure{
  display:grid;
  gap:.75em;
}
.figure__media{
  position:relative;
  display:block;
  width:100%;
  aspect-ratio:var(--ratio,16/10);
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:2px;
  background-color:var(--ink-1);
  background-image:
    radial-gradient(120% 92% at 18% 12%, rgba(91,63,209,.6), transparent 62%),
    radial-gradient(92% 82% at 86% 82%, rgba(46,230,200,.26), transparent 66%),
    radial-gradient(62% 60% at 62% 28%, rgba(255,106,43,.22), transparent 72%),
    linear-gradient(158deg,#0B1233,#241A4D 56%,#05081C);
}
.figure__media > img{
  position:relative;
  z-index:1;
  width:100%;
  height:100%;
  object-fit:cover;
}
.figure__media::after{
  content:"";
  position:absolute;
  inset:0;
  z-index:2;
  pointer-events:none;
  background-image:
    radial-gradient(1.6px 1.6px at 18% 24%, rgba(243,240,232,.85), transparent 60%),
    radial-gradient(1.2px 1.2px at 62% 12%, rgba(46,230,200,.75), transparent 60%),
    radial-gradient(1.8px 1.8px at 82% 68%, rgba(243,240,232,.6), transparent 60%),
    radial-gradient(1.2px 1.2px at 34% 82%, rgba(140,123,255,.85), transparent 60%),
    radial-gradient(1px 1px at 72% 44%, rgba(255,106,43,.8), transparent 60%);
  opacity:.9;
}
.figure__caption{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--dust);
}

/* ---------- 12. 滚动显现 ---------- */
.has-js [data-reveal]{
  opacity:0;
  transform:translateY(16px);
  transition:opacity .55s var(--ease),transform .55s var(--ease);
}
.has-js [data-reveal].is-in{
  opacity:1;
  transform:none;
}

/* ---------- 13. 响应式 ---------- */
@media (max-width:1080px){
  .footer-top{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }
  .footer-brand{grid-column:1 / -1}
}

@media (max-width:900px){
  .masthead__inner{
    grid-template-columns:minmax(0,1fr) auto;
    grid-template-areas:"brand actions";
    padding-block:12px;
  }
  .masthead__meta{display:none}
  .brand{
    grid-area:brand;
    justify-self:start;
    align-items:flex-start;
    text-align:left;
  }
  .masthead__actions{grid-area:actions}
  .nav-toggle{display:inline-flex}

  .site-nav{display:none}
  .site-nav[data-open="true"]{display:block}
  .site-nav .wrap{padding-inline:0}
  .site-nav__list{
    flex-wrap:nowrap;
    justify-content:flex-start;
    gap:10px;
    padding:14px var(--pad);
    overflow-x:auto;
    -webkit-overflow-scrolling:touch;
    scrollbar-width:thin;
  }
  .site-nav__list > li{flex:0 0 auto}
  .site-nav__link{
    padding:8px 12px;
    font-size:14px;
    white-space:nowrap;
    border:1px solid var(--line);
    border-radius:2px;
    background:rgba(11,18,51,.55);
  }
  .site-nav__link::after{display:none}
  .site-nav__link[aria-current="page"]{
    border-color:var(--orange);
    background:rgba(255,106,43,.12);
  }
  .site-nav__link:hover{border-color:var(--nebula-bright)}
}

@media (max-width:900px){
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media (max-width:620px){
  .grid--2,
  .grid--3{grid-template-columns:1fr}
  .section__head{
    grid-template-columns:1fr;
    gap:8px;
  }
  .index-num{font-size:clamp(34px,13vw,54px)}
  .footer-top{grid-template-columns:1fr;gap:26px}
  .footer-col--screen{
    border-left:0;
    padding-left:0;
    padding-top:14px;
    border-top:1px solid rgba(46,230,200,.4);
    background:linear-gradient(180deg,rgba(46,230,200,.08),transparent 80%);
  }
  .footer-meta{
    flex-direction:column;
    align-items:flex-start;
    gap:6px;
  }
  .signal-bar__inner{justify-content:flex-start}
}

@media (max-width:560px){
  .masthead__cta{display:none}
  .brand__name{font-size:22px;letter-spacing:.08em}
  .brand__tagline{font-size:10px;letter-spacing:.3em}
}

/* ---------- 14. 减少动态 ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,
  *::before,
  *::after{
    animation-duration:.001ms!important;
    animation-iteration-count:1!important;
    transition-duration:.001ms!important;
    scroll-behavior:auto!important;
  }
  .has-js [data-reveal]{
    opacity:1!important;
    transform:none!important;
    transition:none!important;
  }
  .btn:hover,
  .card:hover,
  .footer-link:hover{transform:none}
}