/* ============================================================
   BB电子官网 · 共享外壳样式 /assets/site.css
   索引控制台：深墨蓝底 + 电子青路径 + 信号橙留痕
   ============================================================ */

/* ---------- 01 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,li,figure,blockquote,dl,dd{ margin:0; padding:0; }
ul,ol{ list-style:none; }
img,svg,video{ display:block; max-width:100%; }
button{ font:inherit; color:inherit; background:none; border:0; }
a{ color:inherit; }
table{ border-collapse:collapse; }

/* ---------- 02 变量 ---------- */
:root{
  --ink:#0B1729;
  --ink-2:#12243B;
  --rail-line:#1F3A5F;
  --cyan:#39E0D0;
  --signal:#FF7A2F;
  --trace:#8A9BB0;
  --trace-light:#C6D2E0;
  --white:#F2F7FC;
  --ok:#3FD08A;
  --warn:#F0B429;

  --rail-w:248px;
  --shell-max:1180px;

  --r-sm:12px;
  --r-md:18px;
  --r-lg:28px;

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

  --ease-out:cubic-bezier(.22,.61,.36,1);
}

/* ---------- 03 基础排版 ---------- */
body{
  min-height:100%;
  font-family:var(--font-sans);
  font-size:16.5px;
  line-height:1.75;
  color:var(--trace-light);
  background-color:var(--ink);
  background-image:
    radial-gradient(1100px 520px at 10% -10%, rgba(57,224,208,.09), transparent 62%),
    radial-gradient(900px 460px at 98% 2%, rgba(255,122,47,.07), transparent 60%),
    linear-gradient(rgba(31,58,95,.16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(31,58,95,.16) 1px, transparent 1px);
  background-size:auto,auto,64px 64px,64px 64px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

h1,h2,h3,h4{
  color:var(--white);
  font-weight:800;
  line-height:1.15;
  letter-spacing:-.01em;
}
h1{ font-size:clamp(30px,5.6vw,48px); }
h2{ font-size:clamp(23px,3.4vw,32px); }
h3{ font-size:clamp(18px,2.1vw,22px); }
h4{ font-size:17px; }

p{ margin-bottom:1em; }
p:last-child{ margin-bottom:0; }

strong{ color:var(--white); font-weight:700; }

::selection{ background:rgba(57,224,208,.28); color:var(--white); }

/* ---------- 04 焦点可见 ---------- */
:focus{ outline:none; }
:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:2px;
  border-radius:6px;
}

/* ---------- 05 跳过导航 ---------- */
.skip-link{
  position:fixed;
  top:10px;
  left:10px;
  z-index:200;
  padding:10px 16px;
  border-radius:var(--r-sm);
  background:var(--cyan);
  color:var(--ink);
  font-family:var(--font-mono);
  font-size:13px;
  font-weight:700;
  text-decoration:none;
  transform:translateY(-160%);
  transition:transform .2s var(--ease-out);
}
.skip-link:focus,
.skip-link:focus-visible{
  transform:translateY(0);
  outline-color:var(--white);
}

/* ---------- 06 容器与主体 ---------- */
.container{
  width:100%;
  max-width:var(--shell-max);
  margin-inline:auto;
  padding-inline:20px;
}
#main-content{
  display:block;
  padding-block:26px 10px;
}

/* ---------- 07 侧边轨道（移动端 = 顶部条 + 抽屉） ---------- */
.rail{
  position:sticky;
  top:0;
  z-index:70;
  padding:10px 16px 11px;
  background:linear-gradient(180deg,#0E1D33 0%,#0B1729 100%);
  border-bottom:1px solid var(--rail-line);
}

.rail__brand{
  position:relative;
  z-index:90;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:14px;
}

.rail__status{ display:none; }

/* 品牌 */
.brand{
  display:inline-flex;
  align-items:center;
  gap:10px;
  text-decoration:none;
  color:var(--white);
}
.brand__mark{
  flex:none;
  display:grid;
  place-items:center;
  width:36px;
  height:36px;
  border-radius:10px;
  border:1px solid rgba(57,224,208,.45);
  background:linear-gradient(140deg, rgba(57,224,208,.22), rgba(255,122,47,.16));
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:13px;
  font-weight:700;
  letter-spacing:.04em;
}
.brand__text{ display:flex; flex-direction:column; line-height:1.2; }
.brand__name{ font-size:16px; font-weight:800; letter-spacing:.01em; color:var(--white); }
.brand__meta{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  color:var(--trace);
}

/* 抽屉开关 */
.rail__toggle{
  display:inline-flex;
  align-items:center;
  gap:9px;
  padding:8px 12px;
  border-radius:10px;
  border:1px solid var(--rail-line);
  background:rgba(18,36,59,.85);
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.1em;
  cursor:pointer;
  transition:border-color .16s ease, background-color .16s ease;
}
.rail__toggle:hover{ border-color:rgba(57,224,208,.55); background:rgba(57,224,208,.09); }
.rail__toggle-bars{
  position:relative;
  display:block;
  width:16px;
  height:10px;
}
.rail__toggle-bars::before,
.rail__toggle-bars::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  height:1.5px;
  border-radius:2px;
  background:currentColor;
  transition:transform .22s var(--ease-out), opacity .22s var(--ease-out), box-shadow .22s var(--ease-out);
}
.rail__toggle-bars::before{ top:0; box-shadow:0 4.25px 0 currentColor; }
.rail__toggle-bars::after{ bottom:0; }
.rail[data-open="true"] .rail__toggle-bars::before{
  transform:translateY(4.25px) rotate(45deg);
  box-shadow:0 0 0 transparent;
}
.rail[data-open="true"] .rail__toggle-bars::after{
  transform:translateY(-4.25px) rotate(-45deg);
}

/* 抽屉本体 */
.rail__nav{
  position:fixed;
  top:0;
  left:0;
  bottom:0;
  z-index:80;
  width:min(320px,86vw);
  display:flex;
  flex-direction:column;
  gap:14px;
  padding:78px 16px 26px;
  overflow-y:auto;
  background:linear-gradient(180deg,#102138 0%,#0B1729 100%);
  border-right:1px solid var(--rail-line);
  transform:translateX(-104%);
  transition:transform .22s var(--ease-out);
}
.rail__nav[data-open="true"]{
  transform:translateX(0);
  box-shadow:26px 0 60px rgba(3,8,16,.6);
}

.rail__eyebrow{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--trace);
  padding-bottom:10px;
  border-bottom:1px dashed var(--rail-line);
}

.nav-list{
  position:relative;
  display:flex;
  flex-direction:column;
  gap:2px;
}
.nav-indicator{
  position:absolute;
  left:0;
  top:0;
  width:3px;
  height:0;
  border-radius:3px;
  background:linear-gradient(180deg,var(--cyan),rgba(57,224,208,.2));
  opacity:0;
  pointer-events:none;
  transition:transform .18s var(--ease-out), height .18s var(--ease-out), opacity .18s linear;
}
.nav-item{ list-style:none; }
.nav-link{
  display:flex;
  align-items:center;
  gap:12px;
  padding:11px 14px 11px 17px;
  border-radius:10px;
  color:var(--trace-light);
  font-size:15px;
  text-decoration:none;
  transition:background-color .16s ease, color .16s ease;
}
.nav-index{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.05em;
  color:var(--trace);
  transition:color .16s ease;
}
.nav-label{ font-weight:500; }
.nav-link:hover{ background:rgba(57,224,208,.08); color:var(--white); }
.nav-link:hover .nav-index{ color:var(--cyan); }
.nav-link[aria-current="page"]{
  background:linear-gradient(90deg, rgba(57,224,208,.16), rgba(57,224,208,.02));
  color:var(--cyan);
}
.nav-link[aria-current="page"] .nav-index{ color:var(--signal); }
.nav-link[aria-current="page"] .nav-label{ font-weight:700; }

.rail__hint{
  margin-top:auto;
  padding-top:14px;
  border-top:1px dashed var(--rail-line);
  font-size:12.5px;
  line-height:1.7;
  color:var(--trace);
}

/* 轨道底部（桌面常驻，移动端收进抽屉之外的轨道中但隐藏） */
.rail__foot{ display:none; flex-direction:column; gap:12px; }
.rail__note{
  font-size:12px;
  line-height:1.7;
  color:var(--trace);
  margin:0;
}

/* 进度条 */
.rail__progress{
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  height:2px;
  background:rgba(31,58,95,.55);
  overflow:hidden;
}
.rail__progress-bar{
  display:block;
  width:calc(var(--progress,0) * 100%);
  height:100%;
  background:linear-gradient(90deg,var(--cyan),var(--signal));
  transition:width .12s linear;
}

/* 遮罩 */
.rail__scrim{
  position:fixed;
  inset:0;
  z-index:75;
  background:rgba(4,10,20,.64);
  opacity:0;
  pointer-events:none;
  transition:opacity .22s var(--ease-out);
}
.rail[data-open="true"] .rail__scrim{ opacity:1; pointer-events:auto; }

/* ---------- 08 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:11px 16px;
  border-radius:var(--r-sm);
  border:1px solid var(--rail-line);
  background:var(--ink-2);
  color:var(--white);
  font-family:var(--font-mono);
  font-size:13.5px;
  letter-spacing:.02em;
  text-decoration:none;
  cursor:pointer;
  transition:transform .16s var(--ease-out), background-color .16s ease, border-color .16s ease, color .16s ease;
}
.btn:hover{ transform:translateY(-1px); }
.btn--signal{
  border-color:var(--signal);
  background:linear-gradient(135deg,#FF8A45,#FF7A2F);
  color:#0B1729;
  font-weight:700;
  box-shadow:0 14px 28px -18px rgba(255,122,47,.95);
}
.btn--signal:hover{ background:linear-gradient(135deg,#FFA066,#FF8A45); }
.btn--ghost{
  background:transparent;
  border-color:rgba(57,224,208,.45);
  color:var(--cyan);
}
.btn--ghost:hover{ background:rgba(57,224,208,.1); border-color:var(--cyan); }

/* ---------- 09 面包屑 ---------- */
.breadcrumb{ margin-bottom:18px; }
.breadcrumb__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.04em;
}
.breadcrumb__item{ display:inline-flex; align-items:center; color:var(--trace); }
.breadcrumb__item + .breadcrumb__item::before{
  content:"/";
  margin:0 8px;
  color:var(--rail-line);
}
.breadcrumb__link{ color:var(--trace); text-decoration:none; transition:color .16s ease; }
.breadcrumb__link:hover{ color:var(--cyan); }
.breadcrumb__current{ color:var(--cyan); }

/* ---------- 10 索引小件 ---------- */
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--trace);
}
.mono{
  font-family:var(--font-mono);
  font-size:14px;
  letter-spacing:.02em;
  color:var(--cyan);
}
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:3px 9px;
  border-radius:999px;
  border:1px solid var(--rail-line);
  color:var(--trace-light);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.06em;
  white-space:nowrap;
}
.tag--cyan{ color:var(--cyan); border-color:rgba(57,224,208,.42); background:rgba(57,224,208,.08); }
.tag--signal{ color:var(--signal); border-color:rgba(255,122,47,.42); background:rgba(255,122,47,.08); }
.tag--ok{ color:var(--ok); border-color:rgba(63,208,138,.42); background:rgba(63,208,138,.08); }
.tag--warn{ color:var(--warn); border-color:rgba(240,180,41,.42); background:rgba(240,180,41,.08); }

/* 轨道状态点 */
.dot{
  flex:none;
  width:7px;
  height:7px;
  border-radius:50%;
  background:var(--ok);
  box-shadow:0 0 0 3px rgba(63,208,138,.16);
}

/* ---------- 11 图像容器基础规则 ---------- */
.media-frame{
  position:relative;
  width:100%;
  aspect-ratio:16 / 10;
  display:grid;
  place-items:center;
  overflow:hidden;
  border:1px solid var(--rail-line);
  border-radius:var(--r-md);
  background:
    radial-gradient(120% 120% at 14% 8%, #16294A 0%, #0C1930 56%, #0B1729 100%);
}
.media-frame img,
.media-frame svg{
  width:100%;
  height:100%;
  object-fit:cover;
}
.media-frame--wide{ aspect-ratio:21 / 9; }
.media-frame--tall{ aspect-ratio:4 / 5; }
.media-frame--square{ aspect-ratio:1 / 1; }
.media-frame__label{
  position:absolute;
  left:12px;
  bottom:12px;
  padding:4px 9px;
  border-radius:8px;
  border:1px solid var(--rail-line);
  background:rgba(11,23,41,.8);
  color:var(--trace);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
}

/* ---------- 12 显现动画 ---------- */
.has-js [data-reveal]{
  opacity:0;
  transform:translate3d(0,14px,0);
  transition:opacity .42s ease, transform .42s var(--ease-out);
}
.has-js [data-reveal].is-revealed{
  opacity:1;
  transform:none;
}

/* ---------- 13 页脚 ---------- */
.site-foot{
  position:relative;
  margin-top:64px;
  border-top:1px solid var(--rail-line);
  background:linear-gradient(180deg,#0A1524 0%,#0B1729 42%,#091320 100%);
}
.site-foot::before{
  content:"";
  position:absolute;
  top:-1px;
  left:0;
  right:0;
  height:2px;
  background:linear-gradient(90deg,var(--cyan) 0%,rgba(57,224,208,0) 42%,rgba(255,122,47,0) 58%,var(--signal) 100%);
  opacity:.8;
}
.site-foot__inner{ padding-block:42px 26px; }

.site-foot__top{ display:grid; gap:30px; }

.site-foot__line{
  margin:16px 0 0;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.06em;
  color:var(--cyan);
}
.site-foot__note{
  margin:8px 0 0;
  max-width:34ch;
  font-size:13px;
  line-height:1.7;
  color:var(--trace);
}

.site-foot__cols{ display:grid; gap:24px; }
.site-foot__col-title{
  margin:0 0 12px;
  padding-bottom:8px;
  border-bottom:1px dashed var(--rail-line);
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--trace);
}
.site-foot__list{ display:flex; flex-direction:column; gap:9px; }
.site-foot__link{
  display:inline-flex;
  align-items:center;
  gap:8px;
  color:var(--trace-light);
  font-size:14.5px;
  text-decoration:none;
  transition:color .16s ease;
}
.site-foot__link::before{
  content:"";
  width:7px;
  height:1px;
  background:var(--rail-line);
  transition:width .16s var(--ease-out), background-color .16s ease;
}
.site-foot__link:hover{ color:var(--cyan); }
.site-foot__link:hover::before{ width:15px; background:var(--cyan); }

.site-foot__bottom{
  display:grid;
  gap:18px;
  margin-top:32px;
  padding-top:22px;
  border-top:1px solid var(--rail-line);
}
.site-foot__contact{ display:grid; gap:7px; }
.site-foot__contact-item{
  margin:0;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.01em;
  color:var(--trace-light);
  line-height:1.7;
}
.site-foot__k{
  display:inline-block;
  min-width:5.6em;
  margin-right:8px;
  color:var(--trace);
}
.site-foot__legal{
  display:flex;
  flex-wrap:wrap;
  gap:6px 20px;
}
.site-foot__legal-item{
  margin:0;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.04em;
  color:var(--trace);
}

/* ---------- 14 平板 / 桌面 ---------- */
@media (min-width:560px){
  .site-foot__cols{ grid-template-columns:repeat(3,minmax(0,1fr)); }
}

@media (min-width:700px){
  .site-foot__contact{ grid-template-columns:repeat(2,minmax(0,1fr)); gap:7px 26px; }
}

@media (min-width:760px){
  .site-foot__top{ grid-template-columns:1.1fr 2fr; gap:36px; }
  .container{ padding-inline:26px; }
}

@media (min-width:900px){
  .site-foot__bottom{ grid-template-columns:1fr auto; align-items:end; }
}

@media (min-width:1080px){
  body{ padding-left:var(--rail-w); }

  .rail{
    position:fixed;
    top:0;
    left:0;
    bottom:0;
    width:var(--rail-w);
    display:flex;
    flex-direction:column;
    gap:18px;
    padding:24px 18px 20px;
    border-bottom:0;
    border-right:1px solid var(--rail-line);
    background:linear-gradient(180deg,#0D1B2F 0%,#0B1729 58%,#0A1524 100%);
    overflow:hidden;
  }
  .rail__brand{ justify-content:flex-start; }
  .rail__toggle{ display:none; }

  .rail__status{
    display:flex;
    align-items:center;
    gap:9px;
    padding:9px 11px;
    border:1px dashed var(--rail-line);
    border-radius:10px;
    font-family:var(--font-mono);
    font-size:11.5px;
    line-height:1.5;
    letter-spacing:.02em;
    color:var(--trace);
  }

  .rail__nav{
    position:static;
    z-index:auto;
    width:auto;
    flex:1 1 auto;
    min-height:0;
    padding:0;
    gap:10px;
    transform:none;
    border-right:0;
    background:none;
    box-shadow:none;
    overflow-y:auto;
    overscroll-behavior:contain;
  }
  .rail__nav[data-open="true"]{ transform:none; box-shadow:none; }
  .rail__scrim{ display:none; }

  .rail__hint{ margin-top:14px; }

  .rail__foot{
    display:flex;
    padding-top:16px;
    border-top:1px dashed var(--rail-line);
  }
  .rail__foot .btn{ width:100%; }

  .rail__progress{
    left:auto;
    right:0;
    top:0;
    bottom:0;
    width:2px;
    height:auto;
  }
  .rail__progress-bar{
    width:100%;
    height:calc(var(--progress,0) * 100%);
    background:linear-gradient(180deg,var(--cyan),var(--signal));
    transition:height .12s linear;
  }

  #main-content{ padding-block:34px 14px; }
  .site-foot__inner{ padding-block:54px 30px; }
  .site-foot__top{ grid-template-columns:1.35fr 2.4fr; gap:44px; }
}

@media (min-width:1280px){
  :root{ --rail-w:264px; }
}

/* ---------- 15 减少动态 ---------- */
@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior:auto; }
  .has-js [data-reveal]{
    opacity:1 !important;
    transform:none !important;
    transition:none !important;
  }
  .rail__nav,
  .rail__scrim,
  .nav-indicator,
  .rail__toggle-bars::before,
  .rail__toggle-bars::after,
  .rail__progress-bar,
  .btn,
  .skip-link{
    transition-duration:.01ms !important;
  }
}