/* ============================================================
   电玩城游戏厅 · 共享样式 /assets/site.css
   深空靛底 + 霓虹紫罗兰 / 电光青双主色，粗边硬阴影街机铭牌感
   ============================================================ */

/* ---------- 0. 变量 ---------- */
:root{
  color-scheme: dark;

  --c-void:#070B18;
  --c-deep:#0B1A22;
  --c-violet:#A855F7;
  --c-cyan:#22D3EE;
  --c-red:#FF3B5C;
  --c-gold:#F5B942;
  --c-ruby:#7A1E3C;
  --c-ivory:#F4F6FF;
  --c-mist:#93A2C4;
  --c-lilac:#C4B5FD;
  --c-mint:#4ADE80;

  --c-line:rgba(147,162,196,.32);
  --c-line-soft:rgba(147,162,196,.18);

  --f-display: ui-monospace, "Cascadia Mono", "SF Mono", Menlo, Consolas, "Noto Sans SC", system-ui, monospace;
  --f-body: "Noto Sans SC", system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --f-index: ui-monospace, "SF Mono", Menlo, Consolas, "Courier New", monospace;

  --wrap: 1200px;
  --pad: clamp(16px, 4vw, 40px);

  --t-fast: 160ms;
  --t-mid: 240ms;
  --t-slow: 320ms;

  --hard-violet: 4px 4px 0 0 var(--c-violet);
  --hard-cyan: 4px 4px 0 0 var(--c-cyan);
}

/* ---------- 1. Reset ---------- */
*,*::before,*::after{ box-sizing: border-box; }
html{ -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body,h1,h2,h3,h4,h5,p,ul,ol,figure,blockquote,dl,dd{ margin: 0; }
ul,ol{ padding: 0; list-style: none; }
img,svg,video{ display: block; max-width: 100%; }
button,input,select,textarea{ font: inherit; color: inherit; }
button{ background: none; border: 0; cursor: pointer; }
[hidden]{ display: none !important; }

/* ---------- 2. 页面底色与扫描线 ---------- */
body{
  min-height: 100vh;
  background-color: var(--c-void);
  background-image:
    radial-gradient(70vw 55vw at 8% -12%, rgba(168,85,247,.20), transparent 68%),
    radial-gradient(52vw 46vw at 96% 4%, rgba(34,211,238,.14), transparent 66%),
    radial-gradient(48vw 40vw at 74% 104%, rgba(255,59,92,.10), transparent 68%);
  background-repeat: no-repeat;
  background-attachment: fixed;
  color: var(--c-ivory);
  font-family: var(--f-body);
  font-size: 17px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
body::after{
  content: "";
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  background-image: repeating-linear-gradient(180deg, rgba(244,246,255,.028) 0 1px, transparent 1px 3px);
  animation: arc-scan 8s linear infinite;
}
@keyframes arc-scan{
  from{ background-position: 0 0; }
  to{ background-position: 0 24px; }
}

/* ---------- 3. 中文排版基础 ---------- */
h1,h2,h3,h4{
  font-family: var(--f-display);
  font-weight: 500;
  letter-spacing: .02em;
  line-height: 1.04;
  color: var(--c-ivory);
}
h1{ font-size: clamp(40px, 7.5vw, 96px); line-height: .98; text-shadow: 0 0 30px rgba(168,85,247,.35); }
h2{ font-size: clamp(28px, 4.4vw, 52px); }
h3{ font-size: clamp(20px, 2.6vw, 24px); }
h4{ font-size: 19px; }
p{ margin: 0 0 1em; }
a{ color: var(--c-cyan); text-decoration: none; transition: color var(--t-fast) ease; }
a:hover{ color: var(--c-ivory); }
strong{ color: var(--c-ivory); font-weight: 600; }
small{ font-size: 13px; color: var(--c-mist); }
:focus-visible{ outline: 2px solid var(--c-cyan); outline-offset: 3px; }
#main-content, :target{ scroll-margin-top: 150px; }

.arc-prose{
  max-width: 68ch;
  color: #DCE3F7;
  font-size: 17px;
  line-height: 1.75;
}
.arc-prose h2{ margin: 1.6em 0 .6em; font-size: clamp(24px, 3vw, 34px); }
.arc-prose h3{ margin: 1.4em 0 .5em; }
.arc-prose ul{ list-style: none; margin: 0 0 1em; padding: 0; }
.arc-prose li{ position: relative; padding-left: 22px; margin-bottom: .5em; }
.arc-prose li::before{
  content: "▚";
  position: absolute; left: 0; top: 0;
  color: var(--c-cyan);
  font-size: 12px;
}
.arc-prose a{ border-bottom: 1px solid rgba(34,211,238,.55); }

/* ---------- 4. 跳转链接 ---------- */
.arc-skip{
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 999;
  padding: 12px 20px;
  background: var(--c-violet);
  color: #0A0316;
  font-family: var(--f-index);
  font-size: 12.5px;
  letter-spacing: .16em;
  border: 2px solid var(--c-cyan);
}
.arc-skip:focus{ left: 14px; top: 14px; color: #0A0316; }

/* ---------- 5. 头部 ---------- */
.arc-header{
  position: sticky;
  top: 0;
  z-index: 90;
  background: var(--c-void);
  border-bottom: 3px solid var(--c-violet);
}
.arc-header__top{
  display: flex;
  align-items: center;
  gap: clamp(12px, 2.4vw, 28px);
  padding: 10px var(--pad);
  background: linear-gradient(94deg, #070B18 0%, #0B1A22 52%, #17092e 100%);
  border-bottom: 1px solid rgba(168,85,247,.35);
}
.arc-brand{
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--c-ivory);
  text-decoration: none;
}
.arc-brand:hover{ color: var(--c-ivory); }
.arc-brand__mark{
  flex: 0 0 auto;
  width: 38px;
  height: 38px;
  border: 2px solid var(--c-cyan);
  background:
    linear-gradient(135deg, var(--c-violet) 0 42%, transparent 42% 58%, var(--c-red) 58% 100%),
    var(--c-void);
  box-shadow: 3px 3px 0 0 rgba(168,85,247,.85);
  transition: box-shadow var(--t-mid) ease, transform var(--t-mid) ease;
}
.arc-brand:hover .arc-brand__mark{
  transform: translate(-1px,-1px);
  box-shadow: 4px 4px 0 0 var(--c-cyan);
}
.arc-brand__text{ display: flex; flex-direction: column; line-height: 1.25; }
.arc-brand__name{
  font-family: var(--f-display);
  font-size: 15.5px;
  letter-spacing: .06em;
}
.arc-brand__domain{
  font-family: var(--f-index);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--c-mist);
}
.arc-status{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 6px 12px;
  border: 2px solid rgba(34,211,238,.42);
  background: rgba(34,211,238,.07);
  color: var(--c-mist);
  font-family: var(--f-index);
  font-size: 11.5px;
  letter-spacing: .14em;
  white-space: nowrap;
}
.arc-status__dot{
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  background: var(--c-red);
  box-shadow: 0 0 10px rgba(255,59,92,.9);
  animation: arc-pulse 4s ease-in-out infinite;
}
@keyframes arc-pulse{
  0%,100%{ opacity: 1; transform: scale(1); }
  50%{ opacity: .45; transform: scale(.72); }
}
.arc-header__cta{ margin-left: auto; flex: 0 0 auto; }

/* 导航行 */
.arc-navbar{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 0 var(--pad);
  background: rgba(11,26,34,.94);
}
.arc-nav{
  display: flex;
  flex-wrap: wrap;
  align-items: stretch;
  gap: 0;
  margin: 0;
  padding: 0;
}
.arc-nav__link{
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding: 13px 18px;
  color: var(--c-mist);
  font-size: 15px;
  line-height: 1.2;
  text-decoration: none;
  transition: color var(--t-fast) ease, background-color var(--t-fast) ease, box-shadow var(--t-fast) ease;
}
.arc-nav__link::after{
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 2px;
  width: 0;
  background: linear-gradient(90deg, var(--c-cyan), var(--c-violet));
  transition: width var(--t-slow) ease;
}
.arc-nav__link:hover{
  color: var(--c-ivory);
  background: rgba(168,85,247,.12);
}
.arc-nav__link:hover::after{ width: 100%; }
.arc-nav__link[aria-current="page"]{
  color: var(--c-ivory);
  background: rgba(168,85,247,.18);
  box-shadow: inset 0 3px 0 var(--c-violet), inset 0 -3px 0 var(--c-violet);
  text-shadow: 0 0 14px rgba(168,85,247,.75);
}
.arc-nav__link[aria-current="page"]::after{ width: 100%; }
.arc-nav__index{
  font-family: var(--f-index);
  font-size: 10.5px;
  letter-spacing: .18em;
  color: var(--c-cyan);
  opacity: .9;
}

/* 移动端抽屉按钮 */
.arc-nav-toggle{
  display: none;
  align-items: center;
  gap: 10px;
  margin: 10px 0;
  padding: 10px 14px;
  border: 2px solid var(--c-line);
  color: var(--c-ivory);
  font-family: var(--f-index);
  font-size: 11.5px;
  letter-spacing: .18em;
  transition: border-color var(--t-fast) ease, color var(--t-fast) ease, box-shadow var(--t-mid) ease;
}
.arc-nav-toggle:hover{ border-color: var(--c-cyan); color: var(--c-cyan); }
.arc-nav-toggle[aria-expanded="true"]{
  border-color: var(--c-violet);
  color: var(--c-lilac);
  box-shadow: 3px 3px 0 0 var(--c-violet);
}
.arc-nav-toggle__bars{
  display: block;
  width: 22px;
  height: 2px;
  background: currentColor;
  box-shadow: 0 -7px 0 currentColor, 0 7px 0 currentColor;
}
.arc-nav-toggle__label{ line-height: 1; }

/* 滚动进度 */
.arc-progress{
  position: absolute;
  left: 0;
  bottom: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--c-cyan), var(--c-violet) 55%, var(--c-red));
  transition: width 120ms linear;
}

/* ---------- 6. 页脚 ---------- */
.arc-footer{
  margin-top: clamp(64px, 9vw, 120px);
  background: linear-gradient(180deg, #0B1A22 0%, #070B18 62%);
  border-top: 3px solid var(--c-violet);
}
.arc-footer__grid{
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1.2fr;
  gap: clamp(24px, 3vw, 44px);
  max-width: var(--wrap);
  margin: 0 auto;
  padding: clamp(40px, 6vw, 64px) var(--pad) clamp(28px, 4vw, 40px);
}
.arc-footer__brand{
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 10px;
}
.arc-footer__name{
  font-family: var(--f-display);
  font-size: clamp(20px, 2.6vw, 26px);
  letter-spacing: .04em;
  color: var(--c-ivory);
}
.arc-footer__domain{
  font-family: var(--f-index);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--c-lilac);
}
.arc-footer__note{
  max-width: 34ch;
  margin: 0;
  color: var(--c-mist);
  font-size: 14.5px;
  line-height: 1.7;
}
.arc-footer__col{ display: flex; flex-direction: column; gap: 14px; }
.arc-footer__title{
  margin: 0;
  font-family: var(--f-index);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: .18em;
  color: var(--c-cyan);
  text-transform: uppercase;
}
.arc-footer__list{ display: flex; flex-direction: column; gap: 8px; }
.arc-footer__link{
  position: relative;
  display: inline-block;
  padding: 2px 0;
  color: var(--c-mist);
  font-size: 15px;
  line-height: 1.6;
  text-decoration: none;
  transition: color var(--t-fast) ease;
}
.arc-footer__link::after{
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 1px;
  width: 0;
  background: var(--c-cyan);
  transition: width var(--t-mid) ease;
}
.arc-footer__link:hover{ color: var(--c-ivory); }
.arc-footer__link:hover::after{ width: 100%; }

.arc-footer__bar{
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: calc(var(--wrap) + var(--pad) * 2);
  margin: 0 auto;
  padding: 22px var(--pad) clamp(30px, 5vw, 48px);
  border-top: 2px solid var(--c-line-soft);
}
.arc-footer__contact{
  margin: 0;
  font-family: var(--f-index);
  font-size: 12.5px;
  letter-spacing: .06em;
  line-height: 1.9;
  color: var(--c-mist);
}
.arc-footer__service{
  margin: 0;
  max-width: 72ch;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(147,162,196,.85);
}
.arc-footer__legal{
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin: 0;
  padding-top: 10px;
  border-top: 1px solid var(--c-line-soft);
  font-family: var(--f-index);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--c-mist);
}
.arc-footer__copy{ color: rgba(147,162,196,.72); }

/* ---------- 7. 回到顶部 ---------- */
.arc-top{
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 80;
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border: 2px solid var(--c-cyan);
  background: rgba(7,11,24,.92);
  color: var(--c-cyan);
  font-family: var(--f-index);
  font-size: 18px;
  line-height: 1;
  box-shadow: 3px 3px 0 0 var(--c-violet);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity var(--t-mid) ease, transform var(--t-mid) ease, box-shadow var(--t-mid) ease, visibility var(--t-mid) linear;
}
.arc-top[data-visible]{
  opacity: 1;
  visibility: visible;
  transform: none;
}
.arc-top:hover{ box-shadow: 5px 5px 0 0 var(--c-violet); color: var(--c-ivory); }

/* ---------- 8. 容器与网格 ---------- */
.arc-wrap{
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 var(--pad);
}
.arc-wrap--narrow{ max-width: 820px; }

.arc-grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(18px, 2.4vw, 28px);
}
@media (min-width: 860px){
  .arc-grid--7-5{ grid-template-columns: 7fr 5fr; }
  .arc-grid--5-4-3{ grid-template-columns: 5fr 4fr 3fr; }
  .arc-grid--8-4{ grid-template-columns: 8fr 4fr; }
}

/* ---------- 9. 色带与斜切 ---------- */
.arc-band{
  padding: clamp(26px, 4vw, 52px) 0;
  border-top: 2px solid var(--c-line);
  border-bottom: 2px solid var(--c-line);
  background: rgba(11,26,34,.72);
}
.arc-band--violet{
  background: linear-gradient(100deg, rgba(168,85,247,.28), rgba(34,211,238,.12) 58%, transparent);
  border-color: rgba(168,85,247,.5);
}
.arc-band--ruby{
  background: linear-gradient(100deg, rgba(122,30,60,.9), rgba(122,30,60,.35));
  border-color: rgba(255,59,92,.45);
}
.arc-band--cyan{
  background: linear-gradient(100deg, rgba(34,211,238,.16), transparent 72%);
  border-color: rgba(34,211,238,.45);
}
.arc-slant{ clip-path: polygon(0 0, 100% 3.5%, 100% 100%, 0 96.5%); }

/* ---------- 10. 坐标索引条 ---------- */
.arc-coordbar{
  display: flex;
  align-items: stretch;
  margin: 0 0 clamp(26px, 3.4vw, 40px);
  border: 2px solid var(--c-line);
  background: var(--c-deep);
  overflow-x: auto;
  scrollbar-width: thin;
}
.arc-coordbar__item{
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 18px;
  border-right: 2px solid var(--c-line-soft);
  color: var(--c-mist);
  font-size: 14px;
  white-space: nowrap;
  transition: background-color var(--t-fast) ease, color var(--t-fast) ease;
}
.arc-coordbar__item:last-child{ border-right: 0; }
.arc-coordbar__item:hover{ background: rgba(34,211,238,.1); color: var(--c-ivory); }
.arc-coordbar__item[aria-current="location"],
.arc-coordbar__item[aria-current="true"]{
  background: rgba(168,85,247,.2);
  color: var(--c-ivory);
  box-shadow: inset 0 -3px 0 var(--c-violet);
}
.arc-coordbar__code{
  font-family: var(--f-index);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--c-violet);
}
.arc-coordbar__label{ line-height: 1.4; }

/* ---------- 11. 区块头 ---------- */
.arc-section{ padding: clamp(40px, 6vw, 88px) 0; }
.arc-section__head{
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px 24px;
  margin-bottom: clamp(22px, 3vw, 34px);
  padding-bottom: 14px;
  border-bottom: 3px solid rgba(168,85,247,.5);
}
.arc-section__code{
  font-family: var(--f-index);
  font-size: 12.5px;
  letter-spacing: .18em;
  color: var(--c-cyan);
}
.arc-section__title{ margin: 0; font-size: clamp(26px, 3.8vw, 52px); }

/* ---------- 12. 卡片 ---------- */
.arc-card{
  position: relative;
  padding: clamp(18px, 2.4vw, 26px);
  border: 2px solid var(--c-line);
  background: var(--c-deep);
  box-shadow: var(--hard-violet);
  transition: transform var(--t-mid) ease, border-color var(--t-mid) ease, box-shadow var(--t-mid) ease;
}
.arc-card:hover{
  transform: translateY(-2px);
  border-color: var(--c-lilac);
  box-shadow: 4px 4px 0 0 var(--c-violet), 0 0 26px rgba(168,85,247,.35);
}
.arc-card__index{
  font-family: var(--f-index);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--c-cyan);
}
.arc-card__title{
  margin: 10px 0 8px;
  font-size: clamp(20px, 2vw, 22px);
  line-height: 1.3;
}
.arc-card__text{
  margin: 0;
  color: var(--c-mist);
  font-size: 15.5px;
  line-height: 1.7;
}
.arc-card__meta{
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  margin-top: 16px;
  font-family: var(--f-index);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--c-mist);
}
.arc-card--hot{
  border-color: var(--c-violet);
  background: linear-gradient(158deg, #17093a 0%, #0B1A22 74%);
  box-shadow: 4px 4px 0 0 var(--c-cyan);
  animation: arc-glow 4s ease-in-out infinite;
}
@keyframes arc-glow{
  0%,100%{ box-shadow: 4px 4px 0 0 var(--c-cyan); }
  50%{ box-shadow: 4px 4px 0 0 var(--c-cyan), 0 0 30px rgba(34,211,238,.45); }
}

/* ---------- 13. 按钮与徽章 ---------- */
.arc-btn{
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border: 2px solid var(--c-ivory);
  background: transparent;
  color: var(--c-ivory);
  font-family: var(--f-index);
  font-size: 12.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  text-decoration: none;
  line-height: 1;
  transition: transform var(--t-mid) ease, box-shadow var(--t-mid) ease, border-color var(--t-fast) ease, background-color var(--t-fast) ease, color var(--t-fast) ease;
}
.arc-btn:hover{ color: var(--c-ivory); }
.arc-btn--primary{
  border-color: var(--c-violet);
  background: var(--c-violet);
  color: #0A0316;
  box-shadow: 4px 4px 0 0 var(--c-cyan);
}
.arc-btn--primary:hover{
  color: #0A0316;
  transform: translate(-2px,-2px);
  box-shadow: 6px 6px 0 0 var(--c-cyan);
}
.arc-btn--gold{
  border-color: var(--c-gold);
  background: var(--c-gold);
  color: #1A1000;
  box-shadow: 3px 3px 0 0 var(--c-red);
}
.arc-btn--gold:hover{
  color: #1A1000;
  transform: translate(-2px,-2px);
  box-shadow: 5px 5px 0 0 var(--c-red);
}
.arc-btn--ghost{
  border-color: var(--c-line);
  color: var(--c-ivory);
}
.arc-btn--ghost:hover{
  border-color: var(--c-cyan);
  color: var(--c-cyan);
  transform: translate(-1px,-1px);
  box-shadow: 3px 3px 0 0 rgba(34,211,238,.6);
}

.arc-badge{
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 2px solid currentColor;
  color: var(--c-mist);
  font-family: var(--f-index);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  line-height: 1.6;
  white-space: nowrap;
}
.arc-badge--live{ color: var(--c-red); }
.arc-badge--mint{ color: var(--c-mint); }
.arc-badge--gold{ color: var(--c-gold); }
.arc-badge--cyan{ color: var(--c-cyan); }

/* ---------- 14. 面包屑 ---------- */
.arc-crumbs{
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 clamp(18px, 2.4vw, 28px);
  font-family: var(--f-index);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--c-mist);
}
.arc-crumbs__item{
  display: flex;
  align-items: center;
  gap: 8px;
}
.arc-crumbs__item + .arc-crumbs__item::before{
  content: "/";
  color: rgba(147,162,196,.6);
}
.arc-crumbs a{
  color: var(--c-mist);
  border-bottom: 1px solid transparent;
}
.arc-crumbs a:hover{
  color: var(--c-cyan);
  border-bottom-color: var(--c-cyan);
}
.arc-crumbs [aria-current="page"]{ color: var(--c-ivory); }

/* ---------- 15. 图片容器 ---------- */
.arc-frame{
  position: relative;
  overflow: hidden;
  border: 2px solid var(--c-line);
  background: linear-gradient(135deg, #0B1A22, #17093a);
  box-shadow: 4px 4px 0 0 rgba(34,211,238,.5);
}
.arc-frame__img{
  display: block;
  width: 100%;
  height: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  filter: saturate(1.06) contrast(1.05);
  transition: transform var(--t-slow) ease;
}
.arc-frame:hover .arc-frame__img{ transform: scale(1.02); }
.arc-frame--wide .arc-frame__img{ aspect-ratio: 21 / 9; }
.arc-frame--tall .arc-frame__img{ aspect-ratio: 3 / 4; }
.arc-frame--square .arc-frame__img{ aspect-ratio: 1 / 1; }
.arc-frame__ph{
  display: grid;
  place-items: center;
  aspect-ratio: 16 / 10;
  background-color: var(--c-deep);
  background-image:
    linear-gradient(rgba(168,85,247,.18) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34,211,238,.14) 1px, transparent 1px);
  background-size: 24px 24px, 24px 24px;
  color: var(--c-mist);
  font-family: var(--f-index);
  font-size: 11.5px;
  letter-spacing: .18em;
}
.arc-frame--wide .arc-frame__ph{ aspect-ratio: 21 / 9; }
.arc-frame--tall .arc-frame__ph{ aspect-ratio: 3 / 4; }
.arc-frame--square .arc-frame__ph{ aspect-ratio: 1 / 1; }
.arc-frame__cap{
  display: block;
  padding: 10px 14px;
  border-top: 2px solid var(--c-line-soft);
  background: rgba(7,11,24,.8);
  color: var(--c-mist);
  font-family: var(--f-index);
  font-size: 11.5px;
  letter-spacing: .14em;
}

/* ---------- 16. 过滤 chips ---------- */
.arc-chips{
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0 0 clamp(20px, 2.6vw, 30px);
}
.arc-chip{
  padding: 8px 14px;
  border: 2px solid var(--c-line);
  color: var(--c-mist);
  font-family: var(--f-index);
  font-size: 12px;
  letter-spacing: .14em;
  transition: border-color var(--t-fast) ease, color var(--t-fast) ease, background-color var(--t-fast) ease, box-shadow var(--t-mid) ease;
}
.arc-chip:hover{ border-color: var(--c-cyan); color: var(--c-cyan); }
.arc-chip[aria-pressed="true"]{
  border-color: var(--c-violet);
  background: var(--c-violet);
  color: #0A0316;
  box-shadow: 3px 3px 0 0 var(--c-cyan);
}

/* ---------- 17. 选项卡 ---------- */
.arc-tabs{
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  border-bottom: 2px solid var(--c-line);
}
.arc-tab{
  padding: 12px 20px;
  border: 2px solid transparent;
  border-bottom: 0;
  color: var(--c-mist);
  font-family: var(--f-index);
  font-size: 12.5px;
  letter-spacing: .16em;
  transition: color var(--t-fast) ease, background-color var(--t-fast) ease, border-color var(--t-fast) ease;
}
.arc-tab:hover{ color: var(--c-cyan); }
.arc-tab[aria-selected="true"]{
  border-color: var(--c-violet);
  border-bottom-color: var(--c-deep);
  background: rgba(168,85,247,.18);
  color: var(--c-ivory);
  box-shadow: inset 0 -3px 0 var(--c-violet);
}
.arc-tabpanel{ padding: clamp(20px, 3vw, 32px) 0; }

/* ---------- 18. 折叠条文 ---------- */
.arc-fold{
  margin-bottom: 14px;
  border: 2px solid var(--c-line);
  background: var(--c-deep);
  box-shadow: 4px 4px 0 0 rgba(168,85,247,.35);
}
.arc-fold__btn{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 16px 20px;
  color: var(--c-ivory);
  font-size: 17px;
  text-align: left;
  line-height: 1.5;
  transition: color var(--t-fast) ease, background-color var(--t-fast) ease;
}
.arc-fold__btn::after{
  content: "+";
  flex: 0 0 auto;
  color: var(--c-cyan);
  font-family: var(--f-index);
  font-size: 18px;
}
.arc-fold__btn[aria-expanded="true"]{ background: rgba(34,211,238,.08); }
.arc-fold__btn[aria-expanded="true"]::after{ content: "−"; }
.arc-fold__btn:hover{ color: var(--c-cyan); }
.arc-fold__panel{
  padding: 0 20px 20px;
  color: var(--c-mist);
  font-size: 16px;
  line-height: 1.75;
}

/* ---------- 19. 下一站路线条 ---------- */
.arc-next{
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: clamp(40px, 6vw, 64px);
}
.arc-next__link{
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 20px;
  border: 2px solid var(--c-line);
  background: var(--c-deep);
  color: var(--c-ivory);
  text-decoration: none;
  transition: transform var(--t-mid) ease, border-color var(--t-mid) ease, box-shadow var(--t-mid) ease;
}
.arc-next__link:hover{
  transform: translateY(-2px);
  border-color: var(--c-violet);
  box-shadow: 4px 4px 0 0 var(--c-violet);
  color: var(--c-ivory);
}
.arc-next__code{
  font-family: var(--f-index);
  font-size: 11.5px;
  letter-spacing: .18em;
  color: var(--c-cyan);
}

/* ---------- 20. 显现动画 ---------- */
[data-reveal]{
  opacity: 0;
  transform: translateY(10px);
  transition: opacity var(--t-slow) ease, transform var(--t-slow) ease;
}
[data-reveal][data-in]{
  opacity: 1;
  transform: none;
}

/* ---------- 21. 响应式 ---------- */
@media (max-width: 1024px){
  .arc-footer__grid{ grid-template-columns: 1.4fr 1fr 1fr; }
  .arc-footer__brand{ grid-column: 1 / -1; }
}
@media (max-width: 900px){
  .arc-nav-toggle{ display: inline-flex; }
  .arc-nav{
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: auto;
    z-index: 120;
    width: min(88vw, 400px);
    display: flex;
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 4px;
    margin: 0;
    padding: 96px 20px 40px;
    background: linear-gradient(180deg, #0B1A22, #0A0316);
    border-left: 3px solid var(--c-violet);
    box-shadow: -8px 0 0 0 rgba(34,211,238,.35);
    overflow-y: auto;
    transform: translateX(105%);
    transition: transform var(--t-slow) cubic-bezier(.4,0,.2,1);
  }
  .arc-nav[data-open]{ transform: translateX(0); }
  .arc-nav__link{
    flex-direction: row;
    align-items: baseline;
    gap: 12px;
    padding: 16px 10px;
    font-size: 19px;
    border-bottom: 1px solid var(--c-line-soft);
  }
  .arc-nav__link[aria-current="page"]{
    box-shadow: inset 3px 0 0 var(--c-violet);
    border-bottom-color: rgba(168,85,247,.55);
  }
  body[data-nav-locked]{ overflow: hidden; }
  .arc-crumbs{ overflow-x: auto; white-space: nowrap; }
}
@media (max-width: 760px){
  .arc-header__top{ flex-wrap: wrap; row-gap: 10px; }
  .arc-brand{ flex: 1 1 auto; }
  .arc-header__cta{ margin-left: auto; padding: 10px 14px; font-size: 12px; }
  .arc-status{ flex: 1 1 100%; white-space: normal; }
  .arc-navbar{ padding: 0 14px; }
}
@media (max-width: 560px){
  .arc-footer__grid{ grid-template-columns: 1fr; }
  .arc-coordbar{ border-left: 0; border-right: 0; }
  .arc-tab{ padding: 10px 14px; }
  .arc-top{ right: 12px; bottom: 12px; }
}

/* ---------- 22. 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;
  }
  body::after{ animation: none; }
  [data-reveal]{ opacity: 1; transform: none; }
}