/* =====================================================
   必一BSPORTS — 全站共享样式
   /assets/site.css
   信息架构：深空底色 + 电光蓝 + 活力橙
   ===================================================== */

/* ---------- 1. CSS 设计令牌 ---------- */
:root {
  /* 色彩体系 */
  --bg-primary:#0B0E14;
  --bg-secondary:#141925;
  --bg-card:#1A202C;
  --accent-blue:#00B4FF;
  --accent-orange:#FF5A00;
  --text-high:#F5F7FA;
  --text-mid:#A0AFC0;
  --text-low:#6B7A8D;
  --success:#00FFA3;
  --warning:#FFC107;
  --border:#2A3444;

  /* 尺寸与深度 */
  --border-md:1px solid var(--border);
  --border-lg:2px solid var(--border);
  --border-xl:3px solid var(--border);
  --shadow-sm:0 2px 8px rgba(0,0,0,.28);
  --shadow-md:0 8px 24px rgba(0,0,0,.32),4px 4px 0 rgba(0,180,255,.06);
  --shadow-lg:0 18px 40px rgba(0,0,0,.4),8px 8px 0 rgba(0,180,255,.08);

  /* 字体 */
  --font-ui:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",system-ui,-apple-system,sans-serif;
  --font-data:ui-monospace,SFMono-Regular,"SF Mono","JetBrains Mono",Consolas,"Liberation Mono",monospace;

  /* 字号 */
  --text-2xl:clamp(2.5rem,6vw,5rem);
  --text-xl:clamp(2rem,4vw,3rem);
  --text-lg:clamp(1.5rem,2.5vw,2rem);
  --text-md:clamp(1.125rem,1.5vw,1.25rem);
  --text-sm:.875rem;
  --text-xs:.75rem;

  /* 布局 */
  --shell-max:1440px;
  --shell-gap:clamp(16px,4vw,56px);
  --header-h:68px;

  /* 动效 */
  --ease-out:cubic-bezier(.16,1,.3,1);
  --dur-fast:.2s;
  --dur-normal:.3s;
  --dur-slow:.4s;
}

/* ---------- 2. Reset 与基础排版 ---------- */
*,
*::before,
*::after{box-sizing:border-box}

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

body{
  min-height:100vh;
  margin:0;
  background-color:var(--bg-primary);
  background-image:radial-gradient(rgba(255,255,255,.035) 1px,transparent 1px);
  background-size:26px 26px;
  color:var(--text-high);
  font-family:var(--font-ui);
  font-size:16px;
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

h1,h2,h3,h4,h5,h6{
  margin:0 0 .5em;
  line-height:1.15;
  font-weight:900;
  letter-spacing:-.01em;
  text-wrap:balance;
}

p{margin:0}

ul,ol{margin:0;padding:0;list-style:none}

a{
  color:var(--accent-blue);
  text-decoration:none;
  transition:color var(--dur-fast) ease;
}
a:hover{color:var(--text-high);text-decoration:underline}

img,picture,video,canvas,svg{
  display:block;
  max-width:100%;
}

button,input,select,textarea{
  font:inherit;
  color:inherit;
}

button{
  background:none;
  border:none;
  padding:0;
  cursor:pointer;
}

::selection{
  background:var(--accent-blue);
  color:var(--bg-primary);
}

/* ---------- 3. 可访问性与焦点 ---------- */
:focus-visible{
  outline:3px solid var(--accent-blue);
  outline-offset:3px;
}

.skip-link{
  position:fixed;
  top:-100%;
  left:16px;
  z-index:999;
  display:inline-block;
  padding:10px 18px;
  background:var(--accent-blue);
  color:var(--bg-primary);
  font-weight:700;
  font-size:.95rem;
  border:2px solid var(--text-high);
  box-shadow:var(--shadow-md);
  text-decoration:none;
  transition:top var(--dur-fast) ease;
}
.skip-link:hover{
  color:var(--bg-primary);
  text-decoration:none;
}
.skip-link:focus{
  top:12px;
}

.sr-only{
  position:absolute;
  width:1px;
  height:1px;
  padding:0;
  margin:-1px;
  overflow:hidden;
  clip:rect(0 0 0 0);
  white-space:nowrap;
  border:0;
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,
  *::before,
  *::after{
    animation-duration:.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.01ms !important;
  }
}

/* ---------- 4. 布局容器 ---------- */
.shell{
  max-width:var(--shell-max);
  margin:0 auto;
  padding:0 var(--shell-gap);
}

.site-main{
  min-height:calc(100vh - var(--header-h));
}

#main-content{
  scroll-margin-top:calc(var(--header-h) + 16px);
}

/* ---------- 5. 头部命令栏 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:100;
  background:rgba(11,14,20,.88);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
  border-bottom:var(--border-lg);
}

.progress-track{
  position:absolute;
  top:0;
  left:0;
  right:0;
  height:3px;
  overflow:hidden;
  z-index:5;
}

.progress-thumb{
  display:block;
  width:100%;
  height:100%;
  background:linear-gradient(90deg,var(--accent-blue),var(--accent-orange));
  transform:scaleX(0);
  transform-origin:left center;
  will-change:transform;
}

.header-shell{
  position:relative;
  z-index:2;
  max-width:var(--shell-max);
  min-height:var(--header-h);
  margin:0 auto;
  padding:0 var(--shell-gap);
  display:flex;
  align-items:center;
  gap:clamp(12px,2vw,24px);
}

.brand-mark{
  display:inline-flex;
  align-items:center;
  gap:10px;
  flex-shrink:0;
  color:var(--text-high);
  font-size:1.4rem;
  font-weight:900;
  letter-spacing:.02em;
  line-height:1;
  text-decoration:none;
}
.brand-mark:hover{
  color:var(--text-high);
  text-decoration:none;
}

.brand-seal{
  display:grid;
  place-items:center;
  width:34px;
  height:34px;
  background:var(--accent-blue);
  color:var(--bg-primary);
  font-size:1rem;
  font-weight:900;
  transform:skew(-6deg);
  box-shadow:3px 3px 0 rgba(0,180,255,.2);
  border:1px solid rgba(255,255,255,.35);
}
.brand-seal::after{
  content:"";
  position:absolute;
  inset:0;
}

.brand-text{
  font-size:1.28rem;
  letter-spacing:.045em;
  white-space:nowrap;
  font-weight:900;
}

.brand-accent{
  color:var(--accent-blue);
}

.site-nav{
  margin-left:auto;
}

.nav-list{
  display:flex;
  align-items:center;
  gap:2px;
}

.nav-item{
  margin:0;
}

.nav-chip{
  position:relative;
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:10px 10px;
  color:var(--text-mid);
  font-size:.92rem;
  font-weight:500;
  white-space:nowrap;
  text-decoration:none;
  border-bottom:2px solid transparent;
  transition:color var(--dur-fast) ease,border-color var(--dur-fast) ease,background var(--dur-fast) ease;
}
.nav-chip::before{
  content:attr(data-index);
  font-family:var(--font-data);
  font-size:.68rem;
  font-weight:700;
  color:var(--accent-orange);
  opacity:.85;
}
.nav-chip:hover{
  color:var(--text-high);
  background:rgba(255,255,255,.04);
  text-decoration:none;
  border-bottom-color:var(--border);
}
.nav-chip[aria-current="page"]{
  color:var(--text-high);
  border-bottom-color:var(--accent-blue);
}
.nav-chip[aria-current="page"]::after{
  content:"";
  position:absolute;
  left:50%;
  bottom:-2px;
  width:6px;
  height:6px;
  background:var(--accent-orange);
  transform:translateX(-50%) rotate(45deg);
}

.header-actions{
  flex-shrink:0;
  display:flex;
  align-items:center;
  gap:10px;
}

.header-status{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:5px 12px;
  border:1px solid var(--border);
  background:rgba(0,255,163,.05);
  white-space:nowrap;
  font-family:var(--font-data);
  font-size:.72rem;
  letter-spacing:.08em;
  color:var(--text-mid);
}

.status-dot{
  width:7px;
  height:7px;
  border-radius:50%;
  background:var(--success);
  box-shadow:0 0 0 3px rgba(0,255,163,.15);
  animation:status-pulse 2.2s ease-out infinite;
}

@keyframes status-pulse{
  0%,100%{opacity:1}
  50%{opacity:.35}
}

.status-text{
  text-transform:uppercase;
}

/* 汉堡按钮 */
.nav-toggle{
  display:none;
  flex-direction:column;
  justify-content:center;
  gap:5px;
  width:44px;
  height:44px;
  padding:10px;
  background:transparent;
  border:1px solid var(--border);
  cursor:pointer;
  transition:border-color var(--dur-fast) ease;
}
.nav-toggle:hover{
  border-color:var(--accent-blue);
}

.toggle-line{
  display:block;
  width:100%;
  height:2px;
  background:var(--text-high);
  transition:transform var(--dur-normal) var(--ease-out),opacity var(--dur-fast) ease;
}

.nav-toggle[aria-expanded="true"] .toggle-line:nth-child(1){
  transform:translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .toggle-line:nth-child(2){
  opacity:0;
}
.nav-toggle[aria-expanded="true"] .toggle-line:nth-child(3){
  transform:translateY(-7px) rotate(-45deg);
}

/* ---------- 6. 页脚 ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(48px,8vw,96px);
  background:var(--bg-secondary);
  border-top:var(--border-xl);
}
.site-footer::before{
  content:"";
  position:absolute;
  top:-3px;
  left:0;
  right:0;
  height:3px;
  background:linear-gradient(90deg,var(--accent-blue),transparent 70%);
  opacity:.45;
  pointer-events:none;
}

.footer-grid{
  max-width:var(--shell-max);
  margin:0 auto;
  padding:56px var(--shell-gap) 40px;
  display:grid;
  grid-template-columns:1.5fr .8fr 1fr;
  gap:clamp(28px,4vw,64px);
}

.footer-col{
  min-width:0;
}

.footer-name{
  display:flex;
  align-items:center;
  gap:8px;
  font-size:1.2rem;
  font-weight:900;
  letter-spacing:.05em;
  color:var(--text-high);
  margin-bottom:16px;
}

.footer-seal{
  display:grid;
  place-items:center;
  width:26px;
  height:26px;
  background:var(--accent-blue);
  color:var(--bg-primary);
  font-size:.78rem;
  font-weight:900;
  transform:skew(-6deg);
  flex-shrink:0;
}

.footer-desc{
  max-width:34em;
  color:var(--text-mid);
  font-size:.92rem;
  line-height:1.8;
  margin-bottom:20px;
}

.footer-trust{
  display:inline-flex;
  align-items:flex-start;
  gap:10px;
  padding:10px 14px;
  background:var(--bg-card);
  border:1px solid var(--border);
  font-family:var(--font-data);
  font-size:.74rem;
  line-height:1.55;
  color:var(--success);
  max-width:32em;
}

.trust-icon{
  flex-shrink:0;
  display:grid;
  place-items:center;
  width:18px;
  height:18px;
  margin-top:1px;
  background:var(--success);
  color:var(--bg-primary);
  font-size:12px;
  font-weight:900;
  border-radius:50%;
}

.footer-title{
  font-family:var(--font-data);
  font-size:.76rem;
  font-weight:700;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--text-low);
  margin-bottom:16px;
  padding-bottom:10px;
  border-bottom:1px solid var(--border);
}

.footer-list li{
  margin-bottom:10px;
}

.footer-list a{
  position:relative;
  display:inline-block;
  padding-left:16px;
  color:var(--text-mid);
  font-size:.94rem;
  transition:color var(--dur-fast) ease,padding-left var(--dur-fast) ease;
}
.footer-list a::before{
  content:"›";
  position:absolute;
  left:0;
  top:50%;
  transform:translateY(-50%);
  font-family:var(--font-data);
  font-weight:700;
  color:var(--accent-orange);
}
.footer-list a:hover{
  color:var(--text-high);
  padding-left:20px;
  text-decoration:none;
}

.footer-contact .contact-item{
  display:grid;
  grid-template-columns:3.2em 1fr;
  gap:8px;
  margin-bottom:12px;
  color:var(--text-mid);
  font-size:.9rem;
  line-height:1.6;
}

.contact-label{
  font-family:var(--font-data);
  font-size:.72rem;
  letter-spacing:.08em;
  color:var(--text-low);
  text-transform:uppercase;
  padding-top:2px;
}

.contact-value{
  word-break:break-all;
}

.footer-bottom{
  border-top:1px solid var(--border);
  padding:20px var(--shell-gap) 26px;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:center;
  gap:8px 28px;
  text-align:center;
}

.footer-copy,
.footer-icp{
  margin:0;
  font-family:var(--font-data);
  font-size:.78rem;
  color:var(--text-low);
}

/* ---------- 7. 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:12px 24px;
  font-size:.92rem;
  font-weight:700;
  line-height:1;
  text-decoration:none;
  border:2px solid var(--border);
  border-radius:0;
  background:transparent;
  white-space:nowrap;
  transition:background var(--dur-fast) ease,color var(--dur-fast) ease,border-color var(--dur-fast) ease,transform .12s ease,box-shadow var(--dur-fast) ease;
}
.btn:hover{
  text-decoration:none;
  transform:translateY(-1px);
}
.btn:active{
  transform:translateY(1px);
}
.btn-solid{
  background:var(--accent-orange);
  border-color:var(--accent-orange);
  color:var(--bg-primary);
  box-shadow:3px 3px 0 rgba(0,0,0,.35);
}
.btn-solid:hover{
  background:#ff6b26;
  border-color:#ff6b26;
  color:var(--bg-primary);
}
.btn-stroke{
  border-color:var(--accent-blue);
  color:var(--accent-blue);
}
.btn-stroke:hover{
  background:rgba(0,180,255,.08);
  color:var(--text-high);
  border-color:var(--accent-blue);
}
.btn[data-arrow]::after{
  content:"→";
  font-family:var(--font-data);
  font-weight:400;
  transition:transform var(--dur-fast) ease;
}
.btn[data-arrow]:hover::after{
  transform:translateX(3px);
}

/* ---------- 8. 标签 ---------- */
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 10px;
  font-family:var(--font-data);
  font-size:.7rem;
  font-weight:700;
  letter-spacing:.08em;
  line-height:1.4;
  text-transform:uppercase;
  border:1px solid var(--border);
  color:var(--text-mid);
}
.tag-blue{
  color:var(--accent-blue);
  border-color:rgba(0,180,255,.45);
  background:rgba(0,180,255,.06);
}
.tag-orange{
  color:var(--accent-orange);
  border-color:rgba(255,90,0,.45);
  background:rgba(255,90,0,.06);
}
.tag-green{
  color:var(--success);
  border-color:rgba(0,255,163,.4);
  background:rgba(0,255,163,.05);
}
.tag-live{
  color:var(--bg-primary);
  background:var(--accent-orange);
  border-color:var(--accent-orange);
  animation:tag-blink 1.6s step-start infinite;
}
@keyframes tag-blink{
  0%,100%{opacity:1}
  50%{opacity:.82}
}

/* ---------- 9. 卡片面板 ---------- */
.panel{
  background:var(--bg-card);
  border:var(--border-lg);
  box-shadow:var(--shadow-md);
  padding:clamp(20px,3vw,28px);
  transition:border-color var(--dur-normal) ease,transform var(--dur-normal) ease,box-shadow var(--dur-normal) ease;
}
.panel:hover{
  border-color:var(--accent-blue);
  transform:translateY(-2px);
  box-shadow:var(--shadow-lg);
}
.panel-head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  margin-bottom:16px;
}
.panel-title{
  font-size:1.12rem;
  font-weight:900;
  margin:0;
  letter-spacing:.01em;
}
.panel-body{
  font-size:.95rem;
  color:var(--text-mid);
  line-height:1.65;
}
.panel-body p{
  margin:0 0 .8em;
}
.panel-body p:last-child{
  margin-bottom:0;
}

/* ---------- 10. 网格与指标 ---------- */
.grid-cards{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:24px;
}
@media (max-width:960px){
  .grid-cards{grid-template-columns:repeat(2,1fr);gap:16px}
}
@media (max-width:640px){
  .grid-cards{grid-template-columns:1fr}
}

.metric-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(130px,1fr));
  gap:12px;
}

.metric-card{
  padding:16px 14px;
  background:var(--bg-card);
  border:1px solid var(--border);
  border-top:3px solid var(--accent-blue);
  transition:border-color var(--dur-fast) ease,transform var(--dur-fast) ease;
}
.metric-card:hover{
  border-color:var(--accent-blue);
  transform:translateY(-2px);
}

.metric-value{
  display:block;
  font-family:var(--font-data);
  font-size:clamp(1.4rem,2vw,1.9rem);
  font-weight:700;
  line-height:1.2;
  color:var(--text-high);
  font-variant-numeric:tabular-nums;
  letter-spacing:-.01em;
}

.metric-label{
  display:block;
  font-size:.75rem;
  color:var(--text-low);
  letter-spacing:.05em;
  margin-top:4px;
}

/* ---------- 11. 折叠面板 ---------- */
.accordion{
  border-top:var(--border-lg);
}

.accordion-item{
  background:var(--bg-card);
  border-bottom:1px solid var(--border);
  transition:background var(--dur-fast) ease;
}
.accordion-item:last-child{
  border-bottom:var(--border-lg);
}
.accordion-item[data-open]{
  background:var(--bg-secondary);
}

.accordion-head{
  margin:0;
}

.accordion-trigger{
  display:flex;
  align-items:center;
  gap:12px;
  width:100%;
  padding:18px 20px;
  background:transparent;
  border:none;
  font-size:1rem;
  font-weight:700;
  color:var(--text-high);
  text-align:left;
  cursor:pointer;
  transition:background var(--dur-fast) ease;
}
.accordion-trigger:hover{
  background:rgba(255,255,255,.04);
}

.accordion-index{
  font-family:var(--font-data);
  font-size:.78rem;
  font-weight:700;
  color:var(--accent-orange);
  flex-shrink:0;
}

.accordion-label{
  flex:1;
  line-height:1.4;
}

.accordion-icon{
  position:relative;
  flex-shrink:0;
  width:14px;
  height:14px;
}
.accordion-icon::before,
.accordion-icon::after{
  content:"";
  position:absolute;
  top:50%;
  left:50%;
  width:12px;
  height:2px;
  background:var(--accent-blue);
  transform:translate(-50%,-50%);
  transition:transform var(--dur-normal) var(--ease-out),opacity var(--dur-fast) ease;
}
.accordion-icon::after{
  transform:translate(-50%,-50%) rotate(90deg);
}
.accordion-item[data-open] .accordion-icon::after{
  transform:translate(-50%,-50%) rotate(0);
}

.accordion-panel{
  max-height:0;
  overflow:hidden;
  padding:0 20px;
  opacity:0;
  border-top:1px solid transparent;
  transition:max-height var(--dur-slow) var(--ease-out),padding var(--dur-slow) var(--ease-out),opacity var(--dur-normal) ease,border-color var(--dur-fast) ease;
}
.accordion-item[data-open] .accordion-panel{
  max-height:600px;
  padding:16px 20px 20px;
  opacity:1;
  border-top-color:var(--border);
}
.accordion-panel p{
  color:var(--text-mid);
  line-height:1.75;
  font-size:.95rem;
}
.accordion-panel p:last-child{
  margin-bottom:0;
}

/* ---------- 12. 媒体容器 ---------- */
.media-frame{
  position:relative;
  display:block;
  overflow:hidden;
  background:var(--bg-secondary);
  border:var(--border-lg);
  box-shadow:var(--shadow-md);
  aspect-ratio:16/9;
}
.media-frame > img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.media-frame::after{
  content:attr(data-frame-label);
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  padding:6px 10px;
  background:rgba(11,14,20,.82);
  border-top:1px solid var(--border);
  font-family:var(--font-data);
  font-size:.7rem;
  color:var(--text-mid);
}
.media-frame.is-ph{
  display:grid;
  place-items:center;
  min-height:200px;
  background:linear-gradient(135deg,var(--bg-secondary),var(--bg-card));
}
.media-frame.is-ph::before{
  content:"GRAPHIC SLOT — 必一赛事";
  font-family:var(--font-data);
  font-size:.75rem;
  letter-spacing:.1em;
  color:var(--text-low);
}
.media-frame.is-ph::after{
  display:none;
}

/* ---------- 13. 章节编号体系 ---------- */
.chapter{
  padding:clamp(48px,8vw,96px) 0;
}

.chapter-head{
  display:flex;
  align-items:baseline;
  gap:14px;
  margin-bottom:28px;
}

.chapter-index{
  font-family:var(--font-data);
  font-size:clamp(2rem,5vw,3.5rem);
  font-weight:900;
  line-height:1;
  color:var(--accent-orange);
}

.chapter-title{
  font-size:var(--text-xl);
  font-weight:900;
  letter-spacing:-.01em;
  line-height:1.1;
  margin:0;
}

.chapter-meta{
  font-family:var(--font-data);
  font-size:.72rem;
  letter-spacing:.16em;
  color:var(--text-low);
  writing-mode:vertical-rl;
  line-height:1.2;
  align-self:stretch;
  margin-left:2px;
  text-transform:uppercase;
}

/* ---------- 14. 页面头部 ---------- */
.page-head{
  position:relative;
  padding:clamp(48px,8vw,100px) var(--shell-gap) clamp(28px,4vw,48px);
  border-bottom:var(--border-lg);
  max-width:var(--shell-max);
  margin:0 auto;
}
.page-head::before{
  content:"BSPORTS//DATA";
  position:absolute;
  right:var(--shell-gap);
  bottom:12px;
  font-family:var(--font-data);
  font-size:.68rem;
  letter-spacing:.18em;
  color:var(--text-low);
  opacity:.7;
}

.page-kicker{
  display:block;
  font-family:var(--font-data);
  font-size:.78rem;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--accent-orange);
  margin-bottom:14px;
}

.page-title{
  font-size:var(--text-2xl);
  font-weight:900;
  line-height:1.05;
  margin:0 0 18px;
  max-width:14em;
}

.page-intro{
  font-size:var(--text-md);
  color:var(--text-mid);
  line-height:1.65;
  max-width:38em;
  margin:0;
}

.page-head-tags{
  display:flex;
  flex-wrap:wrap;
  gap:6px;
  margin-top:22px;
}

/* ---------- 15. 正文容器 ---------- */
.content-body{
  max-width:860px;
  margin:0 auto;
  font-size:1rem;
  line-height:1.85;
  color:var(--text-mid);
}
.content-body h2{
  font-size:var(--text-lg);
  color:var(--text-high);
  margin-top:2em;
  margin-bottom:.6em;
  letter-spacing:-.01em;
}
.content-body h3{
  font-size:1.2rem;
  color:var(--text-high);
  margin-top:1.6em;
  margin-bottom:.5em;
}
.content-body p{
  margin-bottom:1.2em;
}
.content-body ul,
.content-body ol{
  margin:0 0 1.2em;
  padding-left:1.4em;
}
.content-body li{
  margin-bottom:.45em;
}
.content-body a{
  color:var(--accent-blue);
  text-decoration:underline;
  text-underline-offset:3px;
}
.content-body a:hover{
  color:var(--text-high);
}

/* ---------- 16. 面包屑 ---------- */
.breadcrumb{
  padding:14px var(--shell-gap);
  max-width:var(--shell-max);
  margin:0 auto;
}
.breadcrumb-list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:6px;
  font-family:var(--font-data);
  font-size:.78rem;
  color:var(--text-low);
}
.breadcrumb-list li + li::before{
  content:"/";
  margin-right:6px;
  color:var(--text-low);
  opacity:.6;
}
.breadcrumb-list a{
  color:var(--text-mid);
  text-decoration:none;
  transition:color var(--dur-fast) ease;
}
.breadcrumb-list a:hover{
  color:var(--accent-blue);
}
.breadcrumb-list [aria-current="page"]{
  color:var(--text-high);
  font-weight:700;
}

/* ---------- 17. 分隔线 ---------- */
.divider{
  height:2px;
  border:none;
  background:linear-gradient(90deg,var(--accent-blue),var(--accent-orange) 60%,transparent);
  margin:0;
}

/* ---------- 18. 返回顶部 ---------- */
.backtop{
  position:fixed;
  right:24px;
  bottom:24px;
  z-index:90;
  width:48px;
  height:48px;
  display:grid;
  place-items:center;
  background:var(--bg-card);
  border:2px solid var(--border);
  color:var(--text-mid);
  font-size:1.3rem;
  font-family:var(--font-data);
  cursor:pointer;
  box-shadow:var(--shadow-md);
  opacity:0;
  visibility:hidden;
  transform:translateY(10px);
  transition:opacity var(--dur-normal) ease,transform var(--dur-normal) ease,visibility 0s var(--dur-normal),border-color var(--dur-fast) ease;
}
.backtop:hover{
  border-color:var(--accent-blue);
  color:var(--accent-blue);
}
.backtop[data-shown]{
  opacity:1;
  visibility:visible;
  transform:translateY(0);
  transition:opacity var(--dur-normal) ease,transform var(--dur-normal) ease,visibility 0s;
}

/* ---------- 19. 响应式 ---------- */
@media (max-width:1200px){
  .header-shell{
    gap:12px;
  }
  .nav-chip{
    padding:10px 7px;
    font-size:.86rem;
  }
}

@media (max-width:960px){
  .header-status{
    display:none;
  }

  .nav-toggle{
    display:flex;
  }

  .site-nav{
    position:absolute;
    top:100%;
    left:0;
    right:0;
    margin-left:0;
    background:var(--bg-secondary);
    border-bottom:var(--border-lg);
    box-shadow:var(--shadow-lg);
    max-height:0;
    overflow:hidden;
    opacity:0;
    visibility:hidden;
    transition:max-height var(--dur-slow) var(--ease-out),opacity var(--dur-normal) ease,visibility 0s linear var(--dur-slow);
  }

  .site-nav[data-open]{
    max-height:520px;
    opacity:1;
    visibility:visible;
    transition:max-height var(--dur-slow) var(--ease-out),opacity var(--dur-normal) ease,visibility 0s;
  }

  .nav-list{
    flex-direction:column;
    align-items:stretch;
    padding:12px var(--shell-gap) 24px;
  }

  .nav-chip{
    display:flex;
    align-items:center;
    gap:10px;
    padding:16px 6px;
    border-bottom:1px solid var(--border);
    border-radius:0;
    font-size:1rem;
  }
  .nav-chip:last-child{
    border-bottom:none;
  }
  .nav-chip::before{
    font-size:.76rem;
  }
  .nav-chip[aria-current="page"]{
    background:rgba(0,180,255,.06);
    border-left:4px solid var(--accent-blue);
  }
  .nav-chip[aria-current="page"]::after{
    display:none;
  }

  .footer-grid{
    grid-template-columns:1fr 1fr;
    gap:36px 28px;
  }
  .footer-col-brand{
    grid-column:1 / -1;
  }
}

@media (max-width:640px){
  .brand-text{
    font-size:1.1rem;
  }
  .brand-seal{
    width:30px;
    height:30px;
    font-size:.9rem;
  }

  .footer-grid{
    grid-template-columns:1fr;
    padding:40px var(--shell-gap) 32px;
  }
  .footer-col-brand{
    grid-column:auto;
  }

  .footer-bottom{
    flex-direction:column;
    gap:6px;
  }

  .backtop{
    right:16px;
    bottom:16px;
    width:42px;
    height:42px;
  }

  .page-head{
    padding-left:var(--shell-gap);
    padding-right:var(--shell-gap);
  }
}

/* ---------- 20. 打印 ---------- */
@media print{
  .site-header,
  .site-footer,
  .nav-toggle,
  .backtop,
  .progress-track{
    display:none !important;
  }
  body{
    background:#fff;
    color:#111;
  }
  a{
    color:#000;
    text-decoration:underline;
  }
}