/* ============================================================
   贝博体育 · 共享站点样式 /assets/site.css
   墨蓝指挥中心 · Bento 研究板 · 双层信息导航
   ============================================================ */

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0}
h1,h2,h3,h4,p,ul,ol,figure,blockquote,dl,dd{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,video{display:block;max-width:100%;height:auto}
button{font:inherit;color:inherit;background:none;border:0;margin:0;padding:0;cursor:pointer}
a{color:inherit;text-decoration:none}
table{border-collapse:collapse;width:100%}
input,select,textarea{font:inherit}

:root{
  --ink-950:#050D16;
  --ink-900:#07131F;
  --ink-800:#0B1B2B;
  --ink-700:#13293D;
  --fog:#F4F7FA;
  --mist:#E5EDF4;
  --cyan:#27E1E8;
  --teal:#0B6E75;
  --orange:#FF6A2A;
  --orange-deep:#B43A0B;
  --metal:#8C99A8;
  --metal-light:#C3CCD6;
  --green:#35C48D;
  --amber:#F2B84B;
  --line:rgba(195,204,214,.16);
  --line-firm:rgba(195,204,214,.3);
  --radius-xl:28px;
  --radius-lg:20px;
  --radius-md:14px;
  --radius-pill:999px;
  --shell:1240px;
  --pad:clamp(16px,4vw,40px);
  --ease:cubic-bezier(.2,.7,.3,1);
  --font-body:"Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --font-display:"Barlow Condensed","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
}

html{background:var(--ink-900)}
body{
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.7;
  font-weight:400;
  color:var(--mist);
  background-color:var(--ink-800);
  background-image:
    radial-gradient(920px 520px at 84% -10%,rgba(39,225,232,.10),transparent 70%),
    radial-gradient(760px 480px at 2% 4%,rgba(255,106,42,.07),transparent 72%);
  background-repeat:no-repeat;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

::selection{background:rgba(255,106,42,.85);color:#120A05}

h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:800;
  line-height:1.1;
  letter-spacing:-.015em;
  font-stretch:condensed;
  color:var(--fog);
}
h1{font-size:clamp(2.4rem,6vw,4.8rem)}
h2{font-size:clamp(1.7rem,3.4vw,2.6rem)}
h3{font-size:clamp(1.15rem,2vw,1.5rem);letter-spacing:0}
h4{font-size:1.05rem;letter-spacing:0}
strong,b{font-weight:700;color:var(--fog)}

[id]{scroll-margin-top:132px}

:focus-visible{outline:2px solid var(--cyan);outline-offset:3px;border-radius:4px}

/* ---------- 容器 ---------- */
.bb-shell{
  width:100%;
  max-width:var(--shell);
  margin-inline:auto;
  padding-inline:var(--pad);
}

/* ---------- 跳转链接 ---------- */
.bb-skip{
  position:fixed;
  left:16px;
  top:-80px;
  z-index:300;
  padding:12px 20px;
  border-radius:0 0 12px 12px;
  background:var(--orange);
  color:#120A05;
  font-weight:700;
  font-size:.9rem;
  transition:top .18s var(--ease);
}
.bb-skip:focus{top:0}

/* ============================================================
   头部
   ============================================================ */
.bb-header{
  position:sticky;
  top:0;
  z-index:120;
  background:var(--ink-900);
  border-bottom:1px solid var(--line);
}
.bb-header__strip{
  background:var(--ink-950);
  border-bottom:1px solid rgba(195,204,214,.1);
}
.bb-header__strip-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  min-height:58px;
  padding-block:8px;
}

/* 品牌标记 */
.bb-mark{
  display:inline-flex;
  align-items:center;
  gap:12px;
  min-width:0;
}
.bb-mark__glyph{
  position:relative;
  flex:none;
  width:24px;
  height:24px;
  border-radius:7px;
  background:linear-gradient(135deg,var(--cyan),var(--teal) 62%,var(--ink-700));
  box-shadow:inset 0 0 0 1px rgba(39,225,232,.55),0 0 18px rgba(39,225,232,.22);
}
.bb-mark__glyph::after{
  content:"";
  position:absolute;
  inset:7px;
  border-radius:2px;
  background:var(--orange);
}
.bb-mark__text{
  font-family:var(--font-display);
  font-size:1.22rem;
  font-weight:800;
  letter-spacing:.01em;
  color:var(--fog);
  white-space:nowrap;
}
.bb-mark__tag{
  font-family:var(--font-mono);
  font-size:.68rem;
  font-weight:500;
  letter-spacing:.08em;
  color:var(--metal);
  white-space:nowrap;
  padding-left:14px;
  border-left:1px dashed rgba(195,204,214,.28);
}

.bb-header__meta{
  display:flex;
  align-items:center;
  gap:18px;
  flex:none;
}
.bb-status{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:500;
  letter-spacing:.06em;
  color:var(--metal-light);
  white-space:nowrap;
}
.bb-status__dot{
  width:7px;
  height:7px;
  flex:none;
  border-radius:50%;
  background:var(--green);
  box-shadow:0 0 0 3px rgba(53,196,141,.16);
}

/* 按钮 */
.bb-btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.5em;
  padding:.72em 1.3em;
  border:1px solid transparent;
  border-radius:var(--radius-pill);
  font-family:var(--font-body);
  font-size:.9rem;
  font-weight:700;
  letter-spacing:.02em;
  white-space:nowrap;
  transition:background .18s var(--ease),color .18s var(--ease),
             border-color .18s var(--ease),transform .18s var(--ease);
}
.bb-btn--signal{background:var(--orange);color:#120A05;box-shadow:0 6px 20px rgba(255,106,42,.24)}
.bb-btn--signal:hover{background:#FF824F;transform:translateY(-1px)}
.bb-btn--cyan{background:var(--cyan);color:#04202A}
.bb-btn--cyan:hover{background:#5BEFF4;transform:translateY(-1px)}
.bb-btn--ghost{border-color:var(--line-firm);color:var(--mist)}
.bb-btn--ghost:hover{border-color:var(--cyan);color:var(--cyan)}
.bb-btn--sm{font-size:.78rem;padding:.55em 1.05em}

/* 导航条 */
.bb-header__bar{background:var(--ink-800)}
.bb-header__bar-inner{
  position:relative;
  display:flex;
  align-items:center;
  gap:clamp(10px,2vw,26px);
  min-height:52px;
}
.bb-header__cue{
  flex:none;
  font-family:var(--font-mono);
  font-size:.68rem;
  font-weight:600;
  letter-spacing:.16em;
  color:var(--metal);
  padding-right:16px;
  border-right:1px solid var(--line);
  white-space:nowrap;
}

.bb-nav{flex:1;min-width:0}
.bb-nav__list{display:flex;align-items:center;gap:2px;flex-wrap:wrap}
.bb-nav__item{display:flex;min-width:0}
.bb-nav__link{
  position:relative;
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:13px 11px;
  border-radius:10px;
  font-size:.85rem;
  font-weight:500;
  color:var(--metal);
  white-space:nowrap;
  transition:color .18s var(--ease),background .18s var(--ease);
}
.bb-nav__idx{
  font-family:var(--font-mono);
  font-size:.64rem;
  font-weight:600;
  letter-spacing:.06em;
  color:var(--cyan);
  opacity:.85;
  font-variant-numeric:tabular-nums;
}
.bb-nav__link:hover{color:var(--fog);background:rgba(39,225,232,.08)}
.bb-nav__link[aria-current="page"]{color:var(--fog);font-weight:700}
.bb-nav__link[aria-current="page"]::after{
  content:"";
  position:absolute;
  left:11px;
  right:11px;
  bottom:3px;
  height:3px;
  border-radius:3px;
  background:linear-gradient(90deg,var(--orange),var(--amber));
}
.bb-nav__link[aria-current="page"] .bb-nav__idx{color:var(--orange)}

/* 移动菜单按钮 */
.bb-navtoggle{
  display:none;
  align-items:center;
  gap:10px;
  margin-left:auto;
  padding:9px 15px;
  border:1px solid rgba(195,204,214,.28);
  border-radius:var(--radius-pill);
  background:rgba(19,41,61,.85);
  color:var(--mist);
  font-size:.82rem;
  font-weight:600;
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.bb-navtoggle:hover{border-color:var(--cyan);color:var(--cyan)}
.bb-navtoggle__bars{display:grid;gap:3px;width:16px;flex:none}
.bb-navtoggle__bars span{
  display:block;
  height:2px;
  border-radius:2px;
  background:currentColor;
  transition:transform .2s var(--ease),opacity .2s var(--ease);
}
.bb-navtoggle[aria-expanded="true"] .bb-navtoggle__bars span:nth-child(1){transform:translateY(5px) rotate(45deg)}
.bb-navtoggle[aria-expanded="true"] .bb-navtoggle__bars span:nth-child(2){opacity:0}
.bb-navtoggle[aria-expanded="true"] .bb-navtoggle__bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg)}
.bb-navtoggle__label{line-height:1}

/* 滚动进度 */
.bb-progress{
  position:absolute;
  left:0;
  right:0;
  bottom:-1px;
  height:2px;
  background:rgba(39,225,232,.12);
  pointer-events:none;
}
.bb-progress__bar{
  display:block;
  height:100%;
  width:100%;
  transform:scaleX(0);
  transform-origin:0 50%;
  background:linear-gradient(90deg,var(--cyan),var(--amber) 68%,var(--orange));
  transition:transform .12s linear;
}

/* ============================================================
   页脚
   ============================================================ */
.bb-footer{
  position:relative;
  margin-top:clamp(56px,8vw,110px);
  background:var(--ink-900);
  border-top:1px solid rgba(195,204,214,.14);
  color:var(--mist);
}
.bb-footer::before{
  content:"";
  position:absolute;
  inset:0 0 auto 0;
  height:4px;
  background:linear-gradient(90deg,var(--cyan),var(--teal) 42%,var(--orange) 78%,var(--amber));
}
.bb-footer__grid{
  display:grid;
  grid-template-columns:1.5fr 1fr 1fr 1.35fr;
  gap:clamp(24px,4vw,56px);
  padding-block:clamp(44px,6vw,76px) clamp(32px,4vw,56px);
}
.bb-footer__brand{min-width:0}
.bb-mark--footer .bb-mark__text{font-size:1.3rem}
.bb-footer__lede{
  margin-top:16px;
  max-width:34ch;
  font-size:.92rem;
  line-height:1.8;
  color:var(--metal-light);
}
.bb-status--footer{margin-top:18px;color:var(--metal)}
.bb-footer__col{min-width:0}
.bb-footer__title{
  font-family:var(--font-body);
  font-size:.8rem;
  font-weight:700;
  letter-spacing:.14em;
  color:var(--cyan);
  margin-bottom:16px;
  padding-bottom:10px;
  border-bottom:1px dashed rgba(39,225,232,.3);
}
.bb-footer__list{display:grid;gap:6px}
.bb-footer__link{
  display:inline-block;
  padding:4px 0;
  font-size:.92rem;
  color:var(--metal-light);
  border-bottom:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.bb-footer__link:hover{color:var(--cyan);border-bottom-color:rgba(39,225,232,.5)}
.bb-footer__contact{margin-top:20px;display:grid;gap:8px}
.bb-footer__row{
  display:grid;
  grid-template-columns:44px minmax(0,1fr);
  gap:10px;
  font-size:.86rem;
  line-height:1.55;
}
.bb-footer__label{
  font-family:var(--font-mono);
  font-size:.7rem;
  font-weight:600;
  letter-spacing:.08em;
  color:var(--metal);
  padding-top:3px;
}
.bb-footer__value{color:var(--mist);word-break:break-word}
.bb-footer__base{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:8px 24px;
  padding-block:20px 26px;
  border-top:1px solid rgba(195,204,214,.12);
}
.bb-footer__legal{
  font-family:var(--font-mono);
  font-size:.74rem;
  letter-spacing:.02em;
  color:var(--metal);
}
.bb-footer__legal--muted{color:#6E7C8C}

/* ============================================================
   通用页面与文字组件
   ============================================================ */
.bb-page{padding-bottom:clamp(24px,4vw,48px)}
.bb-section{padding-block:clamp(32px,5vw,64px)}
.bb-section--tight{padding-block:clamp(18px,3vw,32px)}
.bb-lede{
  max-width:68ch;
  font-size:clamp(1rem,1.4vw,1.12rem);
  line-height:1.85;
  color:var(--metal-light);
}
.bb-kicker{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:600;
  letter-spacing:.14em;
  color:var(--cyan);
}
.bb-kicker::before{
  content:"";
  width:24px;
  height:2px;
  flex:none;
  background:var(--orange);
}

.bb-index{
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:600;
  letter-spacing:.1em;
  color:var(--cyan);
  font-variant-numeric:tabular-nums;
}
.bb-num{
  font-family:var(--font-mono);
  font-weight:700;
  color:var(--orange);
  font-variant-numeric:tabular-nums;
}

.bb-pill{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:.4em .9em;
  border:1px solid rgba(39,225,232,.35);
  border-radius:var(--radius-pill);
  background:rgba(39,225,232,.08);
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:600;
  letter-spacing:.06em;
  white-space:nowrap;
}
.bb-pill--signal{
  border-color:rgba(255,106,42,.45);
  background:rgba(255,106,42,.12);
  color:#FFB08A;
}
.bb-pill--quiet{
  border-color:rgba(195,204,214,.28);
  background:rgba(195,204,214,.06);
  color:var(--metal-light);
}
.bb-tag{
  display:inline-block;
  padding:.18em .6em;
  border-radius:6px;
  background:rgba(39,225,232,.14);
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.04em;
}

/* 面包屑 */
.bb-crumbs{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  padding-block:18px;
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.04em;
  color:var(--metal);
}
.bb-crumbs__link{color:var(--cyan)}
.bb-crumbs__link:hover{text-decoration:underline;text-underline-offset:3px}
.bb-crumbs__sep{color:#4A5A6B}
.bb-crumbs__current{color:var(--mist)}

/* 网格 */
.bb-grid{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:clamp(12px,1.6vw,20px);
}

/* Bento 信息板 */
.bb-board{
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  grid-auto-rows:minmax(112px,auto);
  gap:clamp(12px,1.6vw,20px);
}
.bb-tile{
  display:flex;
  flex-direction:column;
  gap:10px;
  padding:clamp(16px,2vw,24px);
  border:1px solid var(--line);
  border-radius:var(--radius-lg);
  background:var(--ink-700);
  min-width:0;
  transition:border-color .2s var(--ease),transform .2s var(--ease),background .2s var(--ease);
}
.bb-tile:hover{border-color:rgba(39,225,232,.45);transform:translateY(-2px)}
.bb-tile--wide{grid-column:span 2}
.bb-tile--tall{grid-row:span 2}
.bb-focus{
  grid-column:span 2;
  grid-row:span 2;
  background:linear-gradient(150deg,rgba(255,106,42,.18),var(--ink-700) 62%);
  border-color:rgba(255,106,42,.4);
}
.bb-focus:hover{border-color:var(--orange)}

/* 卡片 */
.bb-card{
  padding:clamp(18px,2.2vw,28px);
  border:1px solid var(--line);
  border-radius:var(--radius-lg);
  background:var(--ink-700);
  min-width:0;
  transition:border-color .2s var(--ease),transform .2s var(--ease);
}
.bb-card:hover{border-color:rgba(39,225,232,.4);transform:translateY(-2px)}
.bb-card--light{
  background:var(--fog);
  color:var(--ink-700);
  border-color:transparent;
}
.bb-card--light h2,.bb-card--light h3,.bb-card--light h4{color:var(--ink-900)}
.bb-card--light a{color:var(--teal)}
.bb-card--light a:hover{color:var(--orange-deep)}

/* 横向主题带 */
.bb-band{
  position:relative;
  padding:clamp(18px,3vw,30px);
  border:1px solid rgba(39,225,232,.18);
  border-radius:var(--radius-xl);
  background:linear-gradient(100deg,var(--ink-700),var(--ink-800) 56%,var(--ink-900));
  overflow:hidden;
}
.bb-band::before{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  opacity:.55;
  background-image:linear-gradient(90deg,rgba(39,225,232,.1) 1px,transparent 1px);
  background-size:48px 100%;
}

/* 时间轴 */
.bb-timeline{
  position:relative;
  display:grid;
  gap:12px;
  padding-left:26px;
}
.bb-timeline::before{
  content:"";
  position:absolute;
  left:6px;
  top:6px;
  bottom:6px;
  width:2px;
  border-radius:2px;
  background:linear-gradient(180deg,var(--cyan),rgba(39,225,232,.06));
}
.bb-timeline__item{position:relative;padding:10px 0;min-width:0}
.bb-timeline__item::before{
  content:"";
  position:absolute;
  left:-25px;
  top:17px;
  width:12px;
  height:12px;
  border-radius:50%;
  background:var(--ink-800);
  border:2px solid var(--cyan);
}
.bb-timeline__item--signal::before{border-color:var(--orange);background:var(--orange);box-shadow:0 0 0 4px rgba(255,106,42,.18)}

/* 章节目录 */
.bb-toc{
  position:sticky;
  top:132px;
  display:grid;
  gap:2px;
  font-size:.86rem;
}
.bb-toc a{
  display:block;
  padding:7px 12px;
  border-left:2px solid rgba(195,204,214,.2);
  color:var(--metal);
  line-height:1.5;
  transition:color .18s var(--ease),border-color .18s var(--ease),background .18s var(--ease);
}
.bb-toc a:hover{color:var(--fog);background:rgba(39,225,232,.06)}
.bb-toc a[aria-current="true"]{color:var(--cyan);border-left-color:var(--orange)}

/* 折叠面板 */
.bb-accordion{display:grid;gap:10px}
.bb-acc{
  border:1px solid var(--line);
  border-radius:var(--radius-md);
  background:var(--ink-700);
  overflow:hidden;
}
.bb-acc__trigger{
  display:flex;
  width:100%;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding:16px 18px;
  text-align:left;
  font-weight:600;
  font-size:.96rem;
  color:var(--fog);
  transition:background .18s var(--ease),color .18s var(--ease);
}
.bb-acc__trigger:hover{background:rgba(39,225,232,.07);color:var(--cyan)}
.bb-acc__trigger::after{
  content:"+";
  font-family:var(--font-mono);
  font-size:1.15rem;
  line-height:1;
  color:var(--cyan);
  flex:none;
}
.bb-acc__trigger[aria-expanded="true"]::after{content:"–";color:var(--orange)}
.bb-acc__panel{
  padding:0 18px 18px;
  font-size:.94rem;
  line-height:1.8;
  color:var(--metal-light);
}

/* 标签页 */
.bb-tabs{
  display:inline-flex;
  flex-wrap:wrap;
  gap:6px;
  padding:5px;
  border:1px solid var(--line);
  border-radius:var(--radius-pill);
  background:rgba(19,41,61,.85);
}
.bb-tabs__btn{
  padding:.55em 1.1em;
  border-radius:var(--radius-pill);
  font-size:.84rem;
  font-weight:600;
  color:var(--metal);
  transition:background .18s var(--ease),color .18s var(--ease);
}
.bb-tabs__btn:hover{color:var(--fog)}
.bb-tabs__btn[aria-selected="true"]{background:var(--orange);color:#120A05}
.bb-tabpanel[hidden]{display:none}

/* 表格 */
.bb-table{width:100%;font-size:.9rem}
.bb-table th,.bb-table td{
  padding:12px 14px;
  text-align:left;
  border-bottom:1px solid var(--line);
  vertical-align:top;
}
.bb-table th{
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:600;
  letter-spacing:.08em;
  color:var(--cyan);
}
.bb-table tbody tr{transition:background .16s var(--ease)}
.bb-table tbody tr:hover{background:rgba(39,225,232,.06)}
.bb-table--light{background:var(--fog);color:var(--ink-700)}
.bb-table--light th{color:var(--teal)}
.bb-table--light th,.bb-table--light td{border-bottom-color:#C8D5E1}
.bb-table--light tbody tr:hover{background:rgba(11,110,117,.07)}

/* 图片容器 */
.bb-figure{display:grid;gap:10px;min-width:0}
.bb-media{
  position:relative;
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:var(--radius-lg);
  aspect-ratio:16/10;
  background:
    linear-gradient(150deg,var(--ink-700),var(--ink-900)),
    repeating-linear-gradient(90deg,rgba(39,225,232,.08) 0 1px,transparent 1px 40px);
}
.bb-media img{width:100%;height:100%;object-fit:cover}
.bb-media--tall{aspect-ratio:3/4}
.bb-media--square{aspect-ratio:1/1}
.bb-media::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background:linear-gradient(180deg,transparent 42%,rgba(7,19,31,.78));
}
.bb-media__cap{
  position:absolute;
  left:16px;
  right:16px;
  bottom:14px;
  z-index:1;
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.04em;
  color:var(--mist);
}

/* 返回顶部 */
.bb-top{
  position:fixed;
  right:clamp(14px,3vw,28px);
  bottom:clamp(14px,3vw,28px);
  z-index:130;
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:11px 17px;
  border:1px solid rgba(39,225,232,.4);
  border-radius:var(--radius-pill);
  background:rgba(19,41,61,.94);
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:600;
  letter-spacing:.08em;
  opacity:0;
  visibility:hidden;
  transform:translateY(10px);
  transition:opacity .2s var(--ease),transform .2s var(--ease),
             visibility .2s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.bb-top[data-visible="true"]{opacity:1;visibility:visible;transform:none}
.bb-top:hover{color:var(--orange);border-color:var(--orange)}

/* 显现 */
.bb-reveal{
  opacity:0;
  transform:translateY(14px);
  transition:opacity .5s var(--ease),transform .5s var(--ease);
  transition-delay:var(--reveal-delay,0ms);
}
.bb-reveal.is-in{opacity:1;transform:none}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width:1080px){
  .bb-footer__grid{grid-template-columns:1.3fr 1fr 1fr;gap:clamp(22px,3.4vw,40px)}
  .bb-footer__col:last-child{grid-column:1 / -1}
  .bb-footer__contact{grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:8px 24px}
}

@media (max-width:900px){
  .bb-header__cue{display:none}
  .bb-navtoggle{display:inline-flex}
  .bb-nav{
    position:absolute;
    left:0;
    right:0;
    top:100%;
    z-index:140;
    display:none;
    max-height:calc(100dvh - 100px);
    overflow-y:auto;
    background:var(--ink-950);
    border-bottom:1px solid rgba(39,225,232,.22);
    box-shadow:0 28px 48px rgba(0,0,0,.5);
  }
  .bb-nav[data-open="true"]{display:block}
  .bb-nav__list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding:10px var(--pad) 20px;
    flex-wrap:nowrap;
  }
  .bb-nav__item{display:block}
  .bb-nav__link{
    justify-content:flex-start;
    padding:15px 12px;
    border-radius:12px;
    font-size:.98rem;
    border-bottom:1px solid rgba(195,204,214,.1);
    white-space:normal;
  }
  .bb-nav__link[aria-current="page"]{
    background:rgba(255,106,42,.1);
    padding-left:18px;
  }
  .bb-nav__link[aria-current="page"]::after{
    left:0;
    right:auto;
    top:13px;
    bottom:13px;
    width:3px;
    height:auto;
    border-radius:3px;
  }
  .bb-grid{grid-template-columns:repeat(6,minmax(0,1fr))}
  .bb-board{grid-template-columns:repeat(2,minmax(0,1fr))}
  .bb-toc{position:static}
  .bb-footer__grid{grid-template-columns:1fr 1fr}
  .bb-footer__brand{grid-column:1 / -1}
  .bb-footer__col:last-child{grid-column:1 / -1}
}

@media (max-width:640px){
  .bb-header__strip-inner{min-height:52px}
  .bb-mark__tag{display:none}
  .bb-header__meta .bb-btn{display:none}
  .bb-header__meta{gap:0}
  .bb-mark__text{font-size:1.1rem}
  .bb-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .bb-board{grid-template-columns:1fr;grid-auto-rows:auto}
  .bb-tile--wide,.bb-tile--tall,.bb-focus{grid-column:span 1;grid-row:span 1}
  .bb-footer__grid{grid-template-columns:1fr}
  .bb-footer__base{flex-direction:column;align-items:flex-start;gap:6px}
  .bb-top{font-size:.66rem;padding:10px 14px}
  .bb-table{font-size:.84rem}
  .bb-table th,.bb-table td{padding:10px}
}

@media (max-width:400px){
  .bb-status{font-size:.66rem;letter-spacing:.02em}
  .bb-navtoggle__label{display:none}
  .bb-navtoggle{padding:10px 13px}
}

/* ============================================================
   动效可访问性
   ============================================================ */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    transition-delay:0ms !important;
  }
  .bb-reveal{opacity:1;transform:none}
  .bb-tile:hover,.bb-card:hover,.bb-btn:hover{transform:none}
}