/* =========================================================
   麻将胡了 · 全站共享层 /assets/site.css
   骨架：三面牌桌框架 + Bento 模块 + 细线坐标
   ========================================================= */

/* ---------- 1. 设计变量 ---------- */
:root{
  --ivory:#F6F1E3;
  --tile:#FFFDF7;
  --ink:#151915;
  --jade:#1E6B4A;
  --teal:#104D47;
  --cinnabar:#C63B2F;
  --cinnabar-deep:#8F2A22;
  --gold:#C9A24B;
  --wood:#4A3428;
  --mist:#D9E0D2;

  --ink-70:rgba(21,25,21,.70);
  --ink-45:rgba(21,25,21,.45);
  --ink-16:rgba(21,25,21,.16);
  --paper-70:rgba(246,241,227,.70);
  --paper-45:rgba(246,241,227,.45);
  --paper-16:rgba(246,241,227,.16);

  --font-display:"Noto Serif SC","Source Han Serif SC","Songti SC","STSong",serif;
  --font-body:"Noto Sans SC","Source Han Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  --font-mono:"IBM Plex Mono","Roboto Mono",ui-monospace,SFMono-Regular,Menlo,monospace;

  --frame-max:1240px;
  --pad-inline:clamp(18px,4vw,44px);
  --ease:cubic-bezier(.2,.7,.3,1);
  --dur:220ms;
}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.8;
  color:var(--ink);
  background-color:var(--ivory);
  background-image:
    linear-gradient(to right, rgba(21,25,21,.04) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(21,25,21,.04) 1px, transparent 1px);
  background-size:72px 72px;
  background-position:center top;
}
h1,h2,h3,h4,h5{
  margin:0;
  font-family:var(--font-display);
  font-weight:800;
  line-height:1.18;
  letter-spacing:-.02em;
  color:var(--ink);
}
h1{font-size:clamp(32px,4.4vw,56px)}
h2{font-size:clamp(26px,3.2vw,40px)}
h3{font-size:clamp(20px,2.2vw,26px)}
p,figure,blockquote,dl,dd{margin:0}
ul,ol{margin:0}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit}
img,svg,video{display:block;max-width:100%}
table{border-collapse:collapse;width:100%}
strong{font-weight:700}
:focus-visible{outline:2px solid var(--cinnabar);outline-offset:3px}

/* ---------- 3. 跳转链接 ---------- */
.skip-link{
  position:fixed;
  top:10px;
  left:10px;
  z-index:200;
  transform:translateY(-180%);
  background:var(--ink);
  color:var(--ivory);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.14em;
  padding:10px 16px;
  border:1px solid var(--gold);
  transition:transform var(--dur) var(--ease);
}
.skip-link:focus{transform:translateY(0)}

/* ---------- 4. 站点头部：三面牌桌框架 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:80;
  background:var(--ivory);
  border-bottom:2px solid var(--ink);
}
.scroll-progress{
  position:absolute;
  left:0;
  right:0;
  bottom:-2px;
  height:3px;
  z-index:3;
  pointer-events:none;
  background:transparent;
}
.scroll-progress-bar{
  display:block;
  height:100%;
  width:100%;
  background:linear-gradient(90deg,var(--jade),var(--cinnabar));
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform 80ms linear;
}
.frame-inner{
  width:100%;
  max-width:var(--frame-max);
  margin-inline:auto;
  padding-inline:var(--pad-inline);
}
.frame-bar{background:var(--ivory)}
.frame-bar .frame-inner{
  display:flex;
  align-items:center;
  gap:clamp(12px,2vw,26px);
  min-height:76px;
}
.brand{
  display:inline-flex;
  align-items:center;
  gap:12px;
  flex:0 0 auto;
  color:var(--ink);
}
.brand-mark{
  width:42px;
  height:42px;
  display:grid;
  place-items:center;
  background:var(--jade);
  color:var(--tile);
  font-family:var(--font-display);
  font-size:22px;
  font-weight:800;
  line-height:1;
  border:1px solid var(--gold);
  box-shadow:inset 0 0 0 3px rgba(21,25,21,.16);
}
.brand-text{display:flex;flex-direction:column;gap:3px;line-height:1.1}
.brand-name{
  font-family:var(--font-display);
  font-size:20px;
  font-weight:800;
  letter-spacing:.03em;
}
.brand-tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.22em;
  color:var(--jade);
}
.brand-tag::before{content:"";width:5px;height:5px;background:var(--cinnabar)}
.frame-note{
  display:flex;
  align-items:center;
  gap:10px;
  margin-right:auto;
  font-size:12.5px;
  letter-spacing:.02em;
  color:var(--ink-70);
  white-space:nowrap;
}
.frame-coord{
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.08em;
  color:var(--wood);
  border:1px solid var(--ink-16);
  padding:3px 7px;
}
.frame-actions{
  display:flex;
  align-items:center;
  gap:10px;
  margin-left:auto;
}
.frame-cta{
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.14em;
  padding:11px 18px;
}

/* 移动导航按钮 */
.nav-toggle{
  display:none;
  align-items:center;
  gap:8px;
  background:var(--ink);
  color:var(--ivory);
  border:1px solid var(--ink);
  padding:10px 13px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  cursor:pointer;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease);
}
.nav-toggle:hover{background:var(--jade);border-color:var(--jade)}
.nav-toggle-box{position:relative;width:18px;height:14px;display:block}
.nav-toggle-line{
  position:absolute;
  left:0;
  right:0;
  height:2px;
  background:currentColor;
  transition:transform var(--dur) var(--ease),opacity 120ms linear,top var(--dur) var(--ease);
}
.nav-toggle-line:nth-child(1){top:0}
.nav-toggle-line:nth-child(2){top:6px}
.nav-toggle-line:nth-child(3){top:12px}
.site-header[data-open="true"] .nav-toggle-line:nth-child(1){top:6px;transform:rotate(45deg)}
.site-header[data-open="true"] .nav-toggle-line:nth-child(2){opacity:0}
.site-header[data-open="true"] .nav-toggle-line:nth-child(3){top:6px;transform:rotate(-45deg)}

/* 导航条 */
.frame-nav{
  background:var(--ink);
  color:var(--ivory);
  border-top:1px solid rgba(201,162,75,.35);
}
.frame-nav .frame-inner{
  display:flex;
  align-items:stretch;
  justify-content:space-between;
  min-height:52px;
}
.site-nav{display:flex;flex:1;min-width:0}
.nav-list{display:flex;flex:1;list-style:none;padding:0}
.nav-item{
  display:flex;
  border-right:1px solid var(--paper-16);
}
.nav-item:first-child{border-left:1px solid var(--paper-16)}
.nav-link{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:0 clamp(10px,1.6vw,20px);
  color:var(--paper-70);
  font-size:14px;
  letter-spacing:.06em;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease),box-shadow var(--dur) var(--ease);
}
.nav-link::before{
  content:attr(data-index);
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.06em;
  color:var(--gold);
  opacity:.85;
}
.nav-link:hover,.nav-link:focus-visible{
  color:var(--ivory);
  background:rgba(30,107,74,.55);
}
.nav-link[aria-current="page"]{
  background:var(--cinnabar);
  color:var(--ivory);
  box-shadow:inset 0 -3px 0 var(--gold);
}
.nav-link[aria-current="page"]::before{color:var(--ivory);opacity:.9}
.nav-edge{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding-left:18px;
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.18em;
  color:rgba(201,162,75,.85);
  white-space:nowrap;
}
.nav-edge::before{content:"";width:5px;height:5px;background:var(--cinnabar)}

/* ---------- 5. 站脚 ---------- */
.site-footer{
  margin-top:clamp(48px,8vw,96px);
  background:var(--ink);
  color:var(--paper-70);
}
.footer-band{
  height:8px;
  background:linear-gradient(90deg,
    var(--jade) 0 52%,
    var(--gold) 52% 52.6%,
    var(--teal) 52.6% 86%,
    var(--gold) 86% 86.6%,
    var(--cinnabar) 86.6% 100%);
}
.footer-inner{
  width:100%;
  max-width:var(--frame-max);
  margin-inline:auto;
  padding:clamp(34px,6vw,60px) var(--pad-inline) clamp(20px,3vw,28px);
}
.footer-grid{
  display:grid;
  grid-template-columns:1.05fr 1.5fr .8fr;
  gap:clamp(24px,4vw,56px);
  padding-top:clamp(24px,4vw,36px);
  border-top:1px solid var(--paper-16);
}
.footer-col{min-width:0}
.footer-brand{display:flex;flex-direction:column;align-items:flex-start;gap:12px}
.footer-mark{
  width:46px;
  height:46px;
  display:grid;
  place-items:center;
  background:var(--jade);
  color:var(--tile);
  font-family:var(--font-display);
  font-size:22px;
  font-weight:800;
  border:1px solid var(--gold);
}
.footer-brandline{
  font-family:var(--font-display);
  font-size:19px;
  font-weight:700;
  letter-spacing:.04em;
  color:var(--ivory);
  line-height:1.4;
}
.footer-note{
  max-width:30ch;
  font-size:13.5px;
  line-height:1.8;
  color:var(--paper-45);
}
.to-top{
  display:inline-flex;
  align-items:center;
  gap:8px;
  margin-top:6px;
  padding:8px 13px;
  background:transparent;
  border:1px solid rgba(201,162,75,.5);
  color:var(--gold);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  cursor:pointer;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease);
}
.to-top:hover{background:var(--gold);color:var(--ink);border-color:var(--gold)}
.footer-title{
  margin:0 0 14px;
  padding-bottom:10px;
  border-bottom:1px solid var(--paper-16);
  font-family:var(--font-mono);
  font-size:11px;
  font-weight:600;
  letter-spacing:.22em;
  color:var(--gold);
}
.footer-list{
  display:grid;
  gap:9px;
  list-style:none;
  padding:0;
  font-size:14px;
  line-height:1.75;
  color:var(--paper-70);
}
.footer-links{gap:10px}
.footer-link{
  display:inline-flex;
  align-items:center;
  gap:9px;
  color:var(--ivory);
  border-bottom:1px solid transparent;
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.footer-link::before{content:"";width:4px;height:4px;background:var(--gold);flex:0 0 auto}
.footer-link:hover,.footer-link:focus-visible{color:var(--gold);border-bottom-color:var(--gold)}
.footer-meta{
  margin-top:14px;
  max-width:42ch;
  font-family:var(--font-mono);
  font-size:11.5px;
  line-height:1.9;
  letter-spacing:.02em;
  color:var(--paper-45);
}
.footer-mono{font-family:var(--font-mono);letter-spacing:.04em;color:var(--ivory)}
.footer-bottom{
  margin-top:clamp(26px,4vw,42px);
  padding-top:16px;
  border-top:1px solid var(--paper-16);
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  align-items:center;
  gap:10px 20px;
  font-size:12.5px;
  color:var(--paper-45);
}
.footer-copy{letter-spacing:.02em}
.footer-dot{color:var(--gold);margin-inline:4px}
.footer-icp{
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:rgba(201,162,75,.9);
}

/* ---------- 6. 布局容器与章节 ---------- */
.container{
  width:100%;
  max-width:var(--frame-max);
  margin-inline:auto;
  padding-inline:var(--pad-inline);
}
.container-narrow{
  width:100%;
  max-width:860px;
  margin-inline:auto;
  padding-inline:var(--pad-inline);
}
.section{padding-block:clamp(44px,6.5vw,84px)}
.section--tight{padding-block:clamp(28px,4vw,52px)}
.section--band{background:var(--mist)}
.section--dark{background:var(--teal);color:var(--paper-70)}
.section--ink{background:var(--ink);color:var(--paper-70)}
.section--dark .section-title,
.section--ink .section-title,
.section--dark h1,.section--dark h2,.section--dark h3,
.section--ink h1,.section--ink h2,.section--ink h3{color:var(--ivory)}
.section--dark .lead,.section--ink .lead{color:var(--paper-70)}
.section--dark .media-caption,.section--ink .media-caption{color:var(--paper-45)}

.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:9px;
  margin-bottom:14px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.22em;
  color:var(--jade);
}
.eyebrow::before{content:"";width:16px;height:1px;background:var(--cinnabar)}
.section--dark .eyebrow,.section--ink .eyebrow{color:var(--gold)}
.page-title{font-size:clamp(34px,5vw,58px);line-height:1.08}
.section-title{font-size:clamp(26px,3.4vw,40px);line-height:1.16}
.lead{
  margin-top:14px;
  max-width:62ch;
  font-size:clamp(16px,1.4vw,18.5px);
  line-height:1.85;
  color:var(--ink-70);
}

/* ---------- 7. 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:12px 20px;
  border:1px solid transparent;
  border-radius:0;
  background:transparent;
  font-family:var(--font-body);
  font-size:14.5px;
  font-weight:500;
  letter-spacing:.06em;
  line-height:1.2;
  cursor:pointer;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease),border-color var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.btn:active{transform:translateY(1px)}
.btn-primary{background:var(--jade);color:var(--tile);border-color:var(--jade)}
.btn-primary:hover,.btn-primary:focus-visible{background:var(--teal);border-color:var(--teal);color:var(--ivory)}
.btn-accent{background:var(--cinnabar);color:var(--ivory);border-color:var(--cinnabar)}
.btn-accent:hover,.btn-accent:focus-visible{background:var(--cinnabar-deep);border-color:var(--cinnabar-deep)}
.btn-line{background:transparent;color:var(--ink);border-color:var(--ink)}
.btn-line:hover,.btn-line:focus-visible{background:var(--ink);color:var(--ivory)}
.btn-ghost{background:transparent;color:var(--ink);border-color:var(--ink-16)}
.btn-ghost:hover,.btn-ghost:focus-visible{border-color:var(--jade);color:var(--jade);background:rgba(30,107,74,.07)}
.btn-sm{padding:8px 14px;font-size:13px}
.btn-block{width:100%}

/* ---------- 8. 网格与 Bento ---------- */
.grid{display:grid;gap:clamp(14px,2vw,22px)}
.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.bento{
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  grid-auto-rows:minmax(120px,auto);
  gap:clamp(12px,1.6vw,18px);
}
.tile{
  position:relative;
  display:flex;
  flex-direction:column;
  gap:10px;
  padding:clamp(16px,2vw,24px);
  background:var(--tile);
  border:1px solid var(--ink-16);
  box-shadow:4px 4px 0 rgba(21,25,21,.05);
  min-width:0;
}
.tile--wide{grid-column:span 2}
.tile--tall{grid-row:span 2}
.tile--feature{grid-column:span 2;grid-row:span 2}
.tile--band{background:var(--mist)}
.tile--jade{background:var(--jade);border-color:var(--jade);color:var(--tile)}
.tile--ink{background:var(--ink);border-color:var(--ink);color:var(--paper-70)}
.tile--jade .tile-title,.tile--ink .tile-title{color:var(--ivory)}
.tile-index{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  color:var(--gold);
}
.tile-title{
  font-family:var(--font-display);
  font-size:clamp(18px,1.8vw,23px);
  font-weight:700;
  line-height:1.3;
  letter-spacing:-.01em;
}

/* ---------- 9. 媒体容器（占位可复用） ---------- */
.media{
  position:relative;
  width:100%;
  overflow:hidden;
  background:var(--wood);
  border:1px solid var(--ink-16);
}
.media img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.media--wide{aspect-ratio:16/9}
.media--tile{aspect-ratio:4/3}
.media--square{aspect-ratio:1/1}
.media--tall{aspect-ratio:3/4}
.media--framed{padding:8px;background:var(--mist);border-color:var(--ink-16)}
.media-caption{
  display:flex;
  align-items:baseline;
  gap:10px;
  margin-top:9px;
  font-size:12.5px;
  line-height:1.7;
  color:var(--ink-45);
}
.media-caption::before{
  content:"";
  flex:0 0 auto;
  width:20px;
  height:1px;
  background:var(--gold);
}

/* ---------- 10. 正文、面包屑、标签 ---------- */
.prose{
  max-width:70ch;
  font-size:17px;
  line-height:1.85;
  color:var(--ink);
}
.prose p{margin-block:.95em}
.prose h2{margin-block:1.7em .6em;font-size:clamp(23px,2.6vw,31px)}
.prose h3{margin-block:1.5em .55em;font-size:clamp(19px,2vw,24px)}
.prose ul,.prose ol{
  margin-block:.9em;
  padding-left:1.3em;
  display:grid;
  gap:6px;
}
.prose li::marker{color:var(--cinnabar)}
.prose a{color:var(--jade);border-bottom:1px solid rgba(30,107,74,.4)}
.prose a:hover{color:var(--teal);border-bottom-color:var(--teal)}
.prose strong{color:var(--ink)}
.prose blockquote{
  margin-block:1.4em;
  padding:12px 0 12px 18px;
  border-left:3px solid var(--cinnabar);
  color:var(--ink-70);
  background:rgba(217,224,210,.4);
}
.prose code{
  font-family:var(--font-mono);
  font-size:.92em;
  background:rgba(21,25,21,.06);
  padding:1px 5px;
}
.breadcrumbs{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  list-style:none;
  padding:0;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--ink-45);
}
.breadcrumbs li{display:inline-flex;align-items:center;gap:8px}
.breadcrumbs li + li::before{content:"／";color:var(--gold)}
.breadcrumbs a{color:var(--ink-70);border-bottom:1px solid transparent}
.breadcrumbs a:hover{color:var(--jade);border-bottom-color:var(--jade)}
.breadcrumbs [aria-current="page"]{color:var(--cinnabar-deep)}
.divider{
  position:relative;
  height:1px;
  margin-block:clamp(24px,4vw,40px);
  border:0;
  background:var(--ink-16);
}
.divider::after{
  content:"";
  position:absolute;
  left:0;
  top:-1px;
  width:46px;
  height:3px;
  background:var(--gold);
}
.chip{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 9px;
  background:var(--tile);
  border:1px solid var(--ink-16);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.1em;
  color:var(--ink-70);
}
.chip--jade{background:rgba(30,107,74,.08);border-color:rgba(30,107,74,.45);color:var(--jade)}
.chip--gold{background:rgba(201,162,75,.14);border-color:rgba(201,162,75,.6);color:var(--cinnabar-deep)}
.chip--red{background:rgba(198,59,47,.1);border-color:rgba(198,59,47,.45);color:var(--cinnabar-deep)}

/* ---------- 11. 折叠规则面板 ---------- */
.rule-fold{
  background:var(--tile);
  border:1px solid var(--ink-16);
}
.rule-fold + .rule-fold{margin-top:-1px}
.rule-fold summary{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  padding:15px 20px;
  cursor:pointer;
  list-style:none;
  font-family:var(--font-display);
  font-size:17px;
  font-weight:700;
  color:var(--ink);
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease);
}
.rule-fold summary::-webkit-details-marker{display:none}
.rule-fold summary:hover{background:rgba(30,107,74,.07)}
.rule-fold summary::after{
  content:"＋";
  font-family:var(--font-mono);
  font-size:14px;
  color:var(--jade);
}
.rule-fold[open] summary{
  background:var(--mist);
  border-bottom:1px solid var(--ink-16);
}
.rule-fold[open] summary::after{content:"－";color:var(--cinnabar)}
.rule-fold-body{
  padding:16px 20px 20px;
  font-size:15.5px;
  line-height:1.85;
  color:var(--ink-70);
}

/* ---------- 12. 标签切换 ---------- */
.tabbar{
  display:flex;
  flex-wrap:wrap;
  border-bottom:1px solid var(--ink-16);
}
.tab{
  appearance:none;
  padding:11px 18px;
  background:transparent;
  border:1px solid transparent;
  border-bottom:0;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.12em;
  color:var(--ink-70);
  cursor:pointer;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease);
}
.tab:hover{background:rgba(21,25,21,.05);color:var(--ink)}
.tab[aria-selected="true"]{
  background:var(--ink);
  border-color:var(--ink);
  color:var(--ivory);
}
.tabpanel{
  padding-block:clamp(18px,3vw,28px);
  border-bottom:1px solid var(--ink-16);
}
.tabpanel[hidden]{display:none}

/* ---------- 13. 章节目录与高亮 ---------- */
.toc{
  display:grid;
  gap:2px;
  list-style:none;
  padding:0;
  border-left:1px solid var(--ink-16);
}
.toc-link{
  display:flex;
  align-items:baseline;
  gap:10px;
  margin-left:-1px;
  padding:9px 0 9px 14px;
  border-left:2px solid transparent;
  font-size:13.5px;
  line-height:1.6;
  color:var(--ink-70);
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease),background var(--dur) var(--ease);
}
.toc-link::before{
  content:"";
  flex:0 0 auto;
  width:6px;
  height:6px;
  background:var(--ink-16);
  transition:background var(--dur) var(--ease);
}
.toc-link:hover{color:var(--ink);background:rgba(217,224,210,.5)}
.toc-link.is-active{
  color:var(--cinnabar-deep);
  border-left-color:var(--cinnabar);
  font-weight:600;
  background:rgba(198,59,47,.05);
}
.toc-link.is-active::before{background:var(--cinnabar)}

/* ---------- 14. 显现动效 ---------- */
.js-ready [data-reveal]{
  opacity:0;
  transform:translateY(14px);
  transition:opacity 260ms var(--ease),transform 260ms var(--ease);
}
.js-ready [data-reveal].is-visible{
  opacity:1;
  transform:none;
}

/* ---------- 15. 平板 ---------- */
@media (max-width:1080px){
  .frame-note{display:none}
  .nav-edge{display:none}
  .footer-grid{grid-template-columns:1fr 1.4fr}
  .footer-brand{grid-column:1 / -1}
}

/* ---------- 16. 移动导航断点 ---------- */
@media (max-width:900px){
  .nav-toggle{display:inline-flex}
  .frame-bar .frame-inner{min-height:64px;gap:10px}
  .brand-mark{width:38px;height:38px;font-size:20px}
  .brand-name{font-size:18px}
  .frame-nav{display:none;max-height:calc(100vh - 64px);overflow-y:auto}
  .site-header[data-open="true"] .frame-nav{display:block}
  .frame-nav .frame-inner{display:block;padding-block:8px 14px;min-height:0}
  .site-nav{display:block}
  .nav-list{display:block}
  .nav-item{
    display:block;
    border-right:0;
    border-top:1px solid var(--paper-16);
  }
  .nav-item:first-child{border-left:0}
  .nav-link{
    display:flex;
    padding:14px 4px;
    font-size:16px;
    color:var(--paper-70);
  }
  .nav-link[aria-current="page"]{
    box-shadow:inset 3px 0 0 var(--gold);
    padding-left:14px;
  }
  .grid-2,.grid-3{grid-template-columns:1fr}
  .bento{grid-template-columns:repeat(2,minmax(0,1fr))}
  .tile--feature{grid-column:span 2;grid-row:span 1}
}

/* ---------- 17. 手机 ---------- */
@media (max-width:620px){
  body{font-size:16px}
  .frame-cta{padding:9px 12px;font-size:11.5px;letter-spacing:.08em}
  .footer-grid{grid-template-columns:1fr;gap:28px}
  .footer-brand{grid-column:auto}
  .footer-bottom{flex-direction:column;align-items:flex-start;gap:6px}
  .bento{grid-template-columns:1fr;grid-auto-rows:auto}
  .tile--wide,.tile--feature{grid-column:span 1}
  .tile--tall{grid-row:span 1}
  .nav-toggle-text{display:none}
  .nav-toggle{padding:11px}
}
@media (max-width:380px){
  .brand-name{font-size:16px}
  .brand-tag{font-size:9.5px;letter-spacing:.16em}
}

/* ---------- 18. 降低动效偏好 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .js-ready [data-reveal]{opacity:1;transform:none}
  .scroll-progress-bar{transition:none}
}