/* =========================================================
   huohu-cn-plus.com.cn — /assets/site.css
   共享层：reset / 变量 / 中文排版 / 头部 / 页脚 / 基础组件
   ========================================================= */

:root{
  --ink:#0D1116;
  --panel:#151B23;
  --line:#242C37;
  --mist:#9BA6B2;
  --paper:#F2F5F8;
  --fox:#FF4A1C;
  --ember:#FF8A3D;
  --cyan:#1FE0C8;
  --teal:#0B7A72;
  --round:#FFC53D;
  --doc:#EEF1F4;
  --doc-ink:#151B23;

  --rail:72px;
  --bar-h:68px;
  --wrap:1280px;

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

/* ---------- reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  background:var(--ink);
}
body{
  margin:0;
  min-height:100vh;
  padding-left:var(--rail);
  padding-top:var(--bar-h);
  font-family:var(--sans);
  font-size:16px;
  font-weight:400;
  line-height:1.8;
  color:var(--paper);
  background-color:var(--ink);
  background-image:
    radial-gradient(120% 70% at 88% -12%, rgba(255,74,28,.11), transparent 62%),
    radial-gradient(90% 60% at 6% 108%, rgba(31,224,200,.07), transparent 60%);
  background-attachment:fixed;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img,svg,video{display:block;max-width:100%}
h1,h2,h3,h4,h5,p,figure,blockquote{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;cursor:pointer}
strong,b{font-weight:700}

:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:3px;
  border-radius:2px;
}
::selection{background:var(--fox);color:#12161B}

/* ---------- 排版工具 ---------- */
.mono{
  font-family:var(--mono);
  font-variant-numeric:tabular-nums;
  letter-spacing:.02em;
}
.label{
  font-family:var(--mono);
  font-size:12px;
  letter-spacing:.12em;
  text-transform:uppercase;
  color:var(--mist);
}
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--mono);
  font-size:11px;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--fox);
}
.eyebrow::before{
  content:"";
  width:22px;
  height:1px;
  background:currentColor;
}
.index-num{
  display:block;
  font-family:var(--mono);
  font-weight:500;
  font-size:clamp(38px,6vw,60px);
  line-height:1;
  letter-spacing:-.02em;
  color:transparent;
  -webkit-text-stroke:1px var(--fox);
}
.muted{color:var(--mist)}
.cyan{color:var(--cyan)}
.fox{color:var(--fox)}
.prose{max-width:42ch;line-height:1.8}
.note{
  font-size:14px;
  line-height:1.8;
  color:var(--mist);
  border-left:2px solid var(--fox);
  padding-left:14px;
}

/* ---------- 容器与节奏 ---------- */
.wrap{
  width:100%;
  max-width:var(--wrap);
  margin:0 auto;
  padding-left:clamp(20px,4vw,56px);
  padding-right:clamp(20px,4vw,56px);
}
.section{
  position:relative;
  padding:clamp(48px,7vw,88px) 0;
  border-top:1px solid var(--line);
}
.section:first-of-type{border-top:0}

/* ---------- 切角面板 ---------- */
.cut{
  clip-path:polygon(16px 0,100% 0,100% calc(100% - 16px),calc(100% - 16px) 100%,0 100%,0 16px);
}
.panel{
  position:relative;
  background:var(--panel);
  border:1px solid var(--line);
  padding:clamp(18px,2.4vw,28px);
}
.panel--cut{
  border:0;
  background:linear-gradient(160deg,#171E27,#141A22);
  clip-path:polygon(18px 0,100% 0,100% calc(100% - 18px),calc(100% - 18px) 100%,0 100%,0 18px);
}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:10px 20px;
  font-size:14px;
  font-weight:700;
  line-height:1.4;
  letter-spacing:.01em;
  color:var(--paper);
  background:var(--panel);
  border:1px solid var(--line);
  clip-path:polygon(10px 0,100% 0,100% calc(100% - 10px),calc(100% - 10px) 100%,0 100%,0 10px);
  transition:background-color .16s ease,color .16s ease,border-color .16s ease,transform .16s ease;
}
.btn:hover{border-color:var(--fox);background:#1A222C}
.btn:active{transform:translateY(1px)}
.btn--primary{
  color:#12161B;
  background:linear-gradient(135deg,var(--fox),var(--ember));
  border-color:transparent;
  font-weight:800;
}
.btn--primary:hover{background:linear-gradient(135deg,#FF5A2E,#FFA158);border-color:transparent}
.btn--ghost{background:transparent;border-color:var(--line)}
.btn--ghost:hover{background:transparent;border-color:var(--cyan);color:var(--cyan)}

/* ---------- 图片容器基座 ---------- */
.figure{
  position:relative;
  overflow:hidden;
  background:var(--panel);
  border:1px solid var(--line);
}
.figure img{
  width:100%;
  aspect-ratio:16/9;
  object-fit:cover;
  display:block;
  transition:transform .5s ease;
}
.figure:hover img{transform:scale(1.02)}
.figure--wide img{aspect-ratio:21/9}
.figure--tall img{aspect-ratio:3/4}
.figure--square img{aspect-ratio:1/1}
.figure__cap{
  position:absolute;
  left:0;
  bottom:0;
  margin:0;
  padding:7px 14px;
  background:rgba(11,15,20,.84);
  font-family:var(--mono);
  font-size:11px;
  letter-spacing:.08em;
  color:var(--mist);
}

/* ---------- 浅色文档区 ---------- */
.doc-surface{
  background:var(--doc);
  color:var(--doc-ink);
  padding:clamp(32px,5vw,64px) 0;
}
.doc-surface a{color:var(--teal);text-decoration:underline;text-underline-offset:3px}
.doc-surface a:hover{color:var(--fox)}
.doc-surface .note{color:#4A5561;border-left-color:var(--fox)}
.doc-surface code,.doc-surface .mono{color:#0B7A72}

/* =========================================================
   头部
   ========================================================= */
.skip-link{
  position:absolute;
  left:12px;
  top:-70px;
  z-index:140;
  padding:9px 18px;
  font-size:13px;
  font-weight:800;
  color:#12161B;
  background:var(--fox);
  clip-path:polygon(8px 0,100% 0,100% calc(100% - 8px),calc(100% - 8px) 100%,0 100%,0 8px);
  transition:top .16s ease;
}
.skip-link:focus{top:12px}

.read-progress{
  position:fixed;
  top:0;
  left:0;
  right:0;
  height:3px;
  z-index:120;
  background:rgba(36,44,55,.85);
  cursor:pointer;
}
.read-progress__bar{
  display:block;
  width:0;
  height:100%;
  background:linear-gradient(90deg,var(--fox),var(--ember));
  transition:width .12s linear;
}

.site-header{position:relative;z-index:60}

/* 侧边轨道 */
.rail{
  position:fixed;
  top:0;
  left:0;
  bottom:0;
  width:var(--rail);
  z-index:80;
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:4px;
  padding:14px 0 18px;
  background:linear-gradient(180deg,#101620,#0B0F14);
  border-right:1px solid var(--line);
}
.rail__mark{
  position:relative;
  flex:0 0 auto;
  width:40px;
  height:40px;
  display:grid;
  place-items:center;
  margin-bottom:16px;
  font-size:17px;
  font-weight:800;
  color:#101418;
  background:linear-gradient(140deg,var(--fox),var(--ember));
  clip-path:polygon(12px 0,100% 0,100% calc(100% - 12px),calc(100% - 12px) 100%,0 100%,0 12px);
  transition:filter .16s ease;
}
.rail__mark:hover{filter:brightness(1.1)}
.rail__mark-glyph{line-height:1}

.rail__toggle{display:none}

.rail__nav{
  flex:1 1 auto;
  width:100%;
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:2px;
}
.rail__list{
  width:100%;
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:2px;
}
.rail__item{width:100%}
.rail__link{
  position:relative;
  display:flex;
  align-items:center;
  justify-content:center;
  width:100%;
  height:46px;
  color:var(--mist);
  transition:color .16s ease,background-color .16s ease;
}
.rail__glyph{
  font-size:14px;
  font-weight:700;
  line-height:1;
}
.rail__label{
  position:absolute;
  left:calc(100% + 10px);
  top:50%;
  z-index:90;
  white-space:nowrap;
  padding:6px 14px;
  font-size:13px;
  font-weight:700;
  color:var(--paper);
  background:#1A222C;
  border-left:2px solid var(--fox);
  clip-path:polygon(8px 0,100% 0,100% 100%,0 100%,0 8px);
  opacity:0;
  transform:translateY(-50%) translateX(-6px);
  pointer-events:none;
  transition:opacity .16s ease,transform .16s ease;
}
.rail__link:hover,
.rail__link:focus-visible{color:var(--paper);background:rgba(255,74,28,.09)}
.rail__link:hover .rail__label,
.rail__link:focus-visible .rail__label{opacity:1;transform:translateY(-50%) translateX(0)}
.rail__link[aria-current="page"]{color:var(--fox)}
.rail__link[aria-current="page"]::before{
  content:"";
  position:absolute;
  left:0;
  top:50%;
  transform:translateY(-50%);
  width:3px;
  height:22px;
  background:var(--fox);
}
.rail__foot{
  margin-top:auto;
  font-size:9px;
  letter-spacing:.18em;
  color:var(--mist);
  writing-mode:vertical-rl;
  opacity:.65;
}

/* 顶部常驻条 */
.header-bar{
  position:fixed;
  top:0;
  left:var(--rail);
  right:0;
  height:var(--bar-h);
  z-index:70;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:24px;
  padding:0 clamp(18px,3vw,42px);
  background:rgba(13,17,22,.9);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
  border-bottom:1px solid var(--line);
}
.brand{
  flex:1 1 auto;
  min-width:0;
  display:flex;
  flex-direction:column;
  gap:1px;
}
.brand__name{
  font-size:16px;
  font-weight:800;
  line-height:1.25;
  letter-spacing:-.01em;
  color:var(--paper);
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
}
.brand__name::after{
  content:"";
  display:inline-block;
  width:6px;
  height:6px;
  margin-left:9px;
  vertical-align:middle;
  background:var(--fox);
  transform:translateY(-1px);
}
.brand__sub{
  font-size:11.5px;
  line-height:1.3;
  color:var(--mist);
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
}
.brand__meta{
  font-size:10.5px;
  line-height:1.35;
  letter-spacing:.06em;
  color:var(--cyan);
}
.header-actions{
  flex:0 0 auto;
  display:flex;
  align-items:center;
  gap:12px;
}
.round-chip{
  display:inline-flex;
  align-items:center;
  gap:7px;
  height:34px;
  padding:0 12px;
  background:var(--panel);
  border:1px solid var(--line);
  color:var(--mist);
  transition:border-color .16s ease,color .16s ease;
}
.round-chip:hover{border-color:var(--round);color:var(--paper)}
.round-chip__k{
  font-family:var(--mono);
  font-size:9.5px;
  letter-spacing:.14em;
  color:var(--mist);
}
.round-chip__v{
  font-size:14px;
  font-weight:700;
  letter-spacing:.02em;
  color:var(--round);
}

/* =========================================================
   页脚
   ========================================================= */
.site-footer{
  position:relative;
  margin-top:clamp(64px,9vw,120px);
  background:linear-gradient(180deg,#101620,#0A0E13);
  border-top:1px solid var(--line);
}
.site-footer::before{
  content:"";
  position:absolute;
  top:-1px;
  left:0;
  width:clamp(120px,22vw,260px);
  height:2px;
  background:linear-gradient(90deg,var(--fox),rgba(255,74,28,0));
}
.footer__inner{
  padding-top:clamp(40px,5vw,64px);
  padding-bottom:32px;
}
.footer__top{
  display:grid;
  grid-template-columns:minmax(220px,1.05fr) 2fr;
  gap:clamp(28px,4vw,64px);
  align-items:start;
}
.footer__brandname{
  font-size:20px;
  font-weight:800;
  letter-spacing:-.01em;
  color:var(--paper);
}
.footer__brandsub{
  margin-top:5px;
  font-size:12.5px;
  line-height:1.6;
  color:var(--mist);
}
.footer__closing{
  margin-top:18px;
  padding-left:12px;
  border-left:2px solid var(--fox);
  font-size:14px;
  line-height:1.7;
  color:var(--mist);
}
.footer__cols{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:clamp(20px,3vw,40px);
}
.footer__title{
  margin-bottom:14px;
  padding-bottom:11px;
  border-bottom:1px solid var(--line);
  font-family:var(--mono);
  font-size:11px;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--mist);
}
.footer__links{
  display:flex;
  flex-direction:column;
  gap:10px;
}
.footer__links a{
  display:inline-block;
  font-size:14px;
  line-height:1.6;
  color:#C8D0D9;
  transition:color .16s ease,padding-left .16s ease;
}
.footer__links a:hover{color:var(--fox);padding-left:5px}

.footer__contact{
  margin-top:clamp(32px,4vw,52px);
  padding-top:22px;
  border-top:1px solid var(--line);
  display:flex;
  flex-direction:column;
  gap:10px;
}
.footer__contact-line{
  font-size:12.5px;
  line-height:1.7;
  color:var(--cyan);
  overflow-wrap:anywhere;
}
.footer__note{
  max-width:62ch;
  padding-left:12px;
  border-left:2px solid var(--line);
  font-size:12.5px;
  line-height:1.75;
  color:var(--mist);
}
.footer__legal{
  margin-top:28px;
  padding-top:18px;
  border-top:1px solid var(--line);
  display:flex;
  align-items:baseline;
  justify-content:space-between;
  gap:16px;
  flex-wrap:wrap;
  font-size:12px;
  color:var(--mist);
}
.footer__icp{letter-spacing:.02em}
.footer__copy{
  font-size:11.5px;
  letter-spacing:.05em;
  color:var(--mist);
}

/* =========================================================
   显现协议
   ========================================================= */
[data-reveal]{
  opacity:0;
  transform:translateY(12px);
  transition:opacity .4s ease,transform .4s ease;
}
[data-reveal].is-visible{opacity:1;transform:none}

/* =========================================================
   响应式
   ========================================================= */
@media (max-width:1100px){
  .footer__top{grid-template-columns:1fr}
  .footer__cols{grid-template-columns:repeat(3,minmax(0,1fr))}
}

@media (max-width:900px){
  body{
    padding-left:0;
    padding-top:56px;
  }

  /* 轨道塌缩为顶部窄条 */
  .rail{
    top:0;
    left:0;
    right:0;
    bottom:auto;
    width:auto;
    height:56px;
    flex-direction:row;
    align-items:center;
    justify-content:space-between;
    padding:0 12px;
    border-right:0;
    border-bottom:1px solid var(--line);
    background:rgba(11,15,20,.96);
  }
  .rail__mark{width:34px;height:34px;margin:0;font-size:15px}

  .rail__toggle{
    display:inline-flex;
    align-items:center;
    gap:9px;
    height:38px;
    padding:0 12px;
    border:1px solid var(--line);
    background:var(--panel);
    color:var(--paper);
    font-size:12px;
    font-weight:700;
    letter-spacing:.08em;
    clip-path:polygon(8px 0,100% 0,100% calc(100% - 8px),calc(100% - 8px) 100%,0 100%,0 8px);
  }
  .rail__toggle-box{
    display:flex;
    flex-direction:column;
    gap:4px;
    width:16px;
  }
  .rail__toggle-box span{
    display:block;
    height:2px;
    width:100%;
    background:var(--fox);
    transition:transform .16s ease,opacity .16s ease;
  }
  .rail[data-open] .rail__toggle-box span:nth-child(1){transform:translateY(6px) rotate(45deg)}
  .rail[data-open] .rail__toggle-box span:nth-child(2){opacity:0}
  .rail[data-open] .rail__toggle-box span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}

  .rail__nav{
    position:fixed;
    top:56px;
    left:0;
    right:0;
    bottom:0;
    display:none;
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding:14px 0 40px;
    background:#0B0F14;
    overflow-y:auto;
    border-top:1px solid var(--line);
  }
  .rail[data-open] .rail__nav{display:flex}
  .rail__list{align-items:stretch;gap:0}
  .rail__link{
    justify-content:flex-start;
    height:auto;
    gap:14px;
    padding:15px 22px;
    border-bottom:1px solid var(--line);
  }
  .rail__glyph{
    width:30px;
    height:30px;
    display:grid;
    place-items:center;
    border:1px solid var(--line);
    color:var(--fox);
    font-size:13px;
  }
  .rail__label{
    position:static;
    opacity:1;
    transform:none;
    padding:0;
    background:none;
    border-left:0;
    clip-path:none;
    font-size:16px;
    font-weight:700;
    color:inherit;
  }
  .rail__link:hover,
  .rail__link:focus-visible{background:rgba(255,74,28,.07)}
  .rail__link[aria-current="page"]{background:rgba(255,74,28,.09)}
  .rail__link[aria-current="page"]::before{display:none}
  .rail__foot{
    margin-top:16px;
    padding:16px 22px;
    writing-mode:horizontal-tb;
    font-size:10px;
    opacity:.7;
  }

  /* 顶部条回归文档流 */
  .header-bar{
    position:static;
    height:auto;
    padding:12px 18px;
    gap:12px;
    flex-wrap:wrap;
    background:transparent;
    -webkit-backdrop-filter:none;
    backdrop-filter:none;
    border-bottom:1px solid var(--line);
  }
  .brand__sub{display:none}
  .brand__name{font-size:15px}
  .brand__meta{font-size:10px}
  .header-actions{gap:10px}
  .round-chip{height:30px;padding:0 10px}
  .btn{padding:9px 16px;font-size:13px}
}

@media (max-width:640px){
  .wrap{padding-left:18px;padding-right:18px}
  .footer__cols{grid-template-columns:repeat(2,minmax(0,1fr));gap:24px 20px}
  .footer__legal{flex-direction:column;align-items:flex-start;gap:8px}
  .read-progress{height:2px}
}

@media (max-width:420px){
  .brand__meta{display:none}
  .footer__cols{grid-template-columns:1fr}
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.01ms !important;
  }
  [data-reveal]{opacity:1;transform:none}
  .figure:hover img{transform:none}
}