/* ============================================================
   亿百服务 · 全站共享样式 /assets/site.css
   深海蓝基底 + 琥珀行动 + 青瓷绿信息层级
   侧边轨道导航 / 刻度尺母题 / 切角面板
   ============================================================ */

/* ---------- 1. 设计变量 ---------- */
:root{
  --ink-900:#071A31;
  --ink-800:#0B2545;
  --ink-700:#123A63;
  --port-line:#1E4E7E;

  --amber:#E9B44C;
  --amber-soft:#F6D68C;
  --celadon:#3A7D7C;
  --celadon-mist:#8FBDB8;

  --paper:#F4F1EA;
  --graphite:#1A2432;
  --text:#D6E2EE;
  --danger:#C4614A;

  --font-display:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular",ui-monospace,Menlo,Consolas,"Liberation Mono",monospace;

  --rail-w:236px;
  --mobile-bar-h:66px;
  --content-max:1180px;
  --gutter:clamp(18px,4vw,56px);
  --cut:12px;

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

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

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

body{
  margin:0;
  padding-top:var(--mobile-bar-h);
  background:var(--ink-800);
  color:var(--text);
  font-family:var(--font-body);
  font-size:17px;
  font-weight:400;
  line-height:1.9;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  overflow-x:hidden;
}

img,
svg,
video{display:block;max-width:100%;height:auto;}

h1,h2,h3,h4,h5,h6{
  margin:0 0 .5em;
  font-family:var(--font-display);
  font-weight:900;
  line-height:1.12;
  letter-spacing:-.02em;
  color:#fff;
}

p{margin:0 0 1.2em;}
ul,ol{margin:0;padding:0;}

a{color:inherit;}

button{font:inherit;color:inherit;}

hr{border:0;height:1px;background:var(--port-line);margin:0;}

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

@media (min-width:1024px){
  body{padding-top:0;padding-left:var(--rail-w);}
  #main-content{scroll-margin-top:16px;}
}

/* ---------- 3. 可访问性工具 ---------- */
.visually-hidden{
  position:absolute !important;
  width:1px;height:1px;
  margin:-1px;padding:0;
  overflow:hidden;
  clip:rect(0 0 0 0);
  clip-path:inset(50%);
  white-space:nowrap;
  border:0;
}

:focus-visible{
  outline:2px solid var(--amber);
  outline-offset:3px;
}

.skip-link{
  position:fixed;
  top:10px;
  left:10px;
  z-index:400;
  padding:10px 18px;
  background:var(--amber);
  color:var(--ink-900);
  font-weight:700;
  font-size:15px;
  line-height:1.4;
  text-decoration:none;
  transform:translateY(-240%);
  transition:transform .2s var(--ease);
}
.skip-link:focus,
.skip-link:focus-visible{
  transform:translateY(0);
  outline:2px solid var(--ink-900);
  outline-offset:2px;
}
@media (min-width:1024px){
  .skip-link{left:calc(var(--rail-w) + 12px);}
}

/* ---------- 4. 排版基元 ---------- */
.mono{
  font-family:var(--font-mono);
  font-size:14px;
  letter-spacing:.04em;
}

.eyebrow{
  display:inline-block;
  margin:0 0 .9em;
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:500;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--celadon-mist);
}

.section-title{
  margin:0 0 .45em;
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(1.9rem,3.6vw,3rem);
  line-height:1.1;
  letter-spacing:-.02em;
  color:inherit;
}

.chapter-num{
  display:block;
  font-family:var(--font-mono);
  font-size:clamp(2rem,4vw,3.5rem);
  font-weight:500;
  line-height:1;
  letter-spacing:-.02em;
  color:var(--celadon);
  opacity:.5;
  transition:opacity .45s var(--ease),transform .45s var(--ease);
}

/* ---------- 5. 布局工具 ---------- */
.container{
  width:100%;
  max-width:var(--content-max);
  margin-inline:auto;
  padding-inline:var(--gutter);
}

.section{
  padding-block:clamp(48px,7vw,96px);
}

.prose{
  max-width:62ch;
  font-size:17px;
  line-height:1.9;
}

.grid{
  display:grid;
  gap:clamp(16px,2.4vw,28px);
  grid-template-columns:1fr;
}
@media (min-width:640px){
  .grid{grid-template-columns:repeat(2,minmax(0,1fr));}
}
@media (min-width:1024px){
  .grid--3{grid-template-columns:repeat(3,minmax(0,1fr));}
}

/* ---------- 6. 滚动进度 ---------- */
.scroll-progress{
  position:fixed;
  top:0;
  left:0;
  right:0;
  height:3px;
  z-index:300;
  pointer-events:none;
  background:transparent;
}
.scroll-progress-bar{
  display:block;
  height:100%;
  width:100%;
  transform-origin:0 50%;
  transform:scaleX(var(--scroll-x,0));
  background:linear-gradient(90deg,var(--celadon) 0%,var(--celadon-mist) 38%,var(--amber) 100%);
}

/* ---------- 7. 头部 / 侧边轨道 ---------- */
.site-header{
  position:fixed;
  top:0;
  left:0;
  right:0;
  z-index:200;
  background:var(--ink-900);
  color:var(--text);
  border-bottom:1px solid var(--port-line);
}

.rail{position:relative;}

.rail-head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  height:var(--mobile-bar-h);
  padding-inline:16px;
}

/* 品牌 */
.brand{
  display:inline-flex;
  align-items:center;
  gap:10px;
  text-decoration:none;
  color:#fff;
}
.brand-mark{
  flex:none;
  width:16px;
  height:16px;
  background:var(--amber);
  clip-path:polygon(0 0,100% 0,100% 60%,60% 100%,0 100%);
}
.brand-text{
  display:flex;
  flex-direction:column;
  line-height:1.25;
}
.brand-name{
  font-family:var(--font-display);
  font-weight:900;
  font-size:17px;
  letter-spacing:.05em;
  color:#fff;
}
.brand-roman{
  font-family:var(--font-mono);
  font-size:9.5px;
  letter-spacing:.2em;
  color:var(--celadon-mist);
  text-transform:uppercase;
}

/* 移动导航按钮 */
.nav-toggle{
  display:inline-flex;
  flex-direction:column;
  justify-content:center;
  gap:5px;
  flex:none;
  width:44px;
  height:44px;
  padding:0 11px;
  background:rgba(30,78,126,.35);
  border:1px solid var(--port-line);
  color:var(--text);
  cursor:pointer;
  clip-path:polygon(0 0,100% 0,100% 70%,70% 100%,0 100%);
  transition:background .2s var(--ease),border-color .2s var(--ease);
}
.nav-toggle:hover{background:rgba(30,78,126,.65);border-color:var(--celadon-mist);}
.nav-toggle-bar{
  display:block;
  height:2px;
  width:100%;
  background:var(--amber);
  transition:transform .25s var(--ease),opacity .2s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1){transform:translateY(7px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2){opacity:0;}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3){transform:translateY(-7px) rotate(-45deg);}

/* 抽屉 */
.rail-drawer{
  position:absolute;
  top:100%;
  left:0;
  right:0;
  display:none;
  background:var(--ink-900);
  border-top:1px solid var(--port-line);
  border-bottom:1px solid var(--port-line);
  padding:10px 14px 24px;
  max-height:calc(100vh - var(--mobile-bar-h));
  max-height:calc(100dvh - var(--mobile-bar-h));
  overflow-y:auto;
  -webkit-overflow-scrolling:touch;
}
.rail-drawer[data-open]{display:block;}

/* 导航 */
.site-nav{display:block;}

.nav-list{
  list-style:none;
  margin:0;
  padding:0;
  display:flex;
  flex-direction:column;
  gap:2px;
}

.nav-item{list-style:none;}

.nav-link{
  display:flex;
  align-items:baseline;
  gap:12px;
  padding:14px 12px;
  border-left:2px solid transparent;
  color:var(--text);
  text-decoration:none;
  transition:color .2s var(--ease),background .2s var(--ease),border-color .2s var(--ease);
}
.nav-num{
  flex:none;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  color:var(--celadon);
  transition:color .2s var(--ease);
}
.nav-label{
  font-size:17px;
  font-weight:500;
  letter-spacing:.01em;
}
.nav-link:hover,
.nav-link:focus-visible{
  color:#fff;
  background:rgba(30,78,126,.45);
  border-left-color:var(--celadon-mist);
}
.nav-link[aria-current="page"]{
  color:var(--amber-soft);
  border-left-color:var(--amber);
  background:linear-gradient(90deg,rgba(233,180,76,.20),rgba(233,180,76,0) 88%);
}
.nav-link[aria-current="page"] .nav-num{color:var(--amber);}
.nav-link[aria-current="page"] .nav-label{font-weight:700;}

/* 轨道底部 */
.rail-foot{
  margin-top:22px;
  padding-top:18px;
  border-top:1px solid var(--port-line);
}
.rail-tagline{
  margin:0 0 14px;
  font-size:13px;
  line-height:1.75;
  color:var(--celadon-mist);
}
.utility-list{
  list-style:none;
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  margin:0 0 16px;
  padding:0;
}
.utility-item{
  padding:4px 8px;
  border:1px solid var(--port-line);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.06em;
  line-height:1.5;
  color:var(--celadon-mist);
}
.rail-foot .btn{
  font-size:13.5px;
  padding:12px 12px;
  letter-spacing:.02em;
}

/* 桌面端：转为左侧全高轨道 */
@media (min-width:1024px){
  .site-header{
    right:auto;
    bottom:0;
    width:var(--rail-w);
    border-bottom:0;
    border-right:1px solid var(--port-line);
  }
  .site-header::after{
    content:"";
    position:absolute;
    top:0;
    bottom:0;
    right:0;
    width:14px;
    pointer-events:none;
    background:repeating-linear-gradient(to bottom,var(--port-line) 0 1px,transparent 1px 12px);
    opacity:.55;
  }
  .rail{
    display:flex;
    flex-direction:column;
    height:100%;
    padding:26px 20px 24px;
    overflow-y:auto;
  }
  .rail-head{
    height:auto;
    padding-inline:0;
    flex-direction:column;
    align-items:flex-start;
    gap:0;
  }
  .brand{flex-direction:column;align-items:flex-start;gap:12px;}
  .brand-mark{width:22px;height:22px;}
  .brand-name{font-size:20px;letter-spacing:.06em;}
  .brand-roman{letter-spacing:.26em;font-size:10px;}
  .nav-toggle{display:none;}

  .rail-drawer{
    position:static;
    display:flex;
    flex-direction:column;
    flex:1 1 auto;
    max-height:none;
    margin-top:28px;
    padding:0;
    border:0;
    background:transparent;
    overflow:visible;
  }
  .nav-link{padding:11px 10px;gap:12px;}
  .nav-label{font-size:15px;}
  .rail-foot{margin-top:auto;}
}

/* ---------- 8. 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  padding:13px 22px;
  font-family:var(--font-body);
  font-size:15px;
  font-weight:700;
  line-height:1.35;
  text-align:center;
  text-decoration:none;
  border:1px solid transparent;
  border-radius:0;
  cursor:pointer;
  transition:transform .2s var(--ease),background .2s var(--ease),
             border-color .2s var(--ease),color .2s var(--ease);
}
.btn--amber{
  background:var(--amber);
  border-color:var(--amber);
  color:var(--ink-900);
  clip-path:polygon(0 0,100% 0,100% 66%,72% 100%,0 100%);
}
.btn--amber:hover{
  background:var(--amber-soft);
  border-color:var(--amber-soft);
  transform:translateY(-2px);
}
.btn--amber:focus-visible{
  outline:2px solid var(--amber-soft);
  outline-offset:3px;
}
.btn--ghost{
  background:transparent;
  border-color:var(--port-line);
  color:var(--text);
}
.btn--ghost:hover{
  border-color:var(--amber);
  color:var(--amber-soft);
  transform:translateY(-2px);
}
.btn--block{width:100%;}

/* ---------- 9. 页脚 ---------- */
.site-footer{
  position:relative;
  background:var(--ink-900);
  color:var(--text);
  border-top:1px solid var(--port-line);
  overflow:hidden;
}
.site-footer::before{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  opacity:.16;
  background-image:
    linear-gradient(var(--port-line) 1px,transparent 1px),
    linear-gradient(90deg,var(--port-line) 1px,transparent 1px);
  background-size:48px 48px;
  -webkit-mask-image:linear-gradient(to bottom,#000 0%,transparent 74%);
  mask-image:linear-gradient(to bottom,#000 0%,transparent 74%);
}

.footer-inner{
  position:relative;
  z-index:1;
  max-width:var(--content-max);
  margin-inline:auto;
  padding:clamp(40px,6vw,76px) var(--gutter) 30px;
}
.footer-inner::before{
  content:"";
  display:block;
  height:10px;
  margin-bottom:clamp(28px,4.5vw,50px);
  background:repeating-linear-gradient(90deg,var(--port-line) 0 1px,transparent 1px 16px);
  opacity:.9;
}

.footer-lead{margin:0 0 clamp(30px,4.5vw,54px);}
.footer-brand{
  margin:0;
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(28px,5vw,44px);
  line-height:1;
  letter-spacing:-.02em;
  color:#fff;
}
.footer-coord{
  margin:14px 0 0;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.2em;
  color:var(--celadon-mist);
  text-transform:uppercase;
}

.footer-grid{
  display:grid;
  gap:clamp(26px,4vw,48px);
  grid-template-columns:1fr;
}
@media (min-width:640px){
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr));}
}
@media (min-width:1024px){
  .footer-grid{grid-template-columns:repeat(3,minmax(0,1fr));}
}

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

.footer-title{
  margin:0 0 14px;
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:500;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--celadon);
  padding-bottom:10px;
  border-bottom:1px solid var(--port-line);
}

.footer-links{
  list-style:none;
  display:flex;
  flex-direction:column;
  gap:10px;
  margin:0;
  padding:0;
}
.footer-link{
  display:inline-block;
  font-size:15px;
  line-height:1.7;
  color:var(--text);
  text-decoration:none;
  transition:color .2s var(--ease),transform .2s var(--ease);
}
.footer-link:hover,
.footer-link:focus-visible{
  color:var(--amber-soft);
  transform:translateX(3px);
}
.footer-link--meta{
  font-size:13.5px;
  line-height:1.75;
  word-break:break-word;
  color:var(--celadon-mist);
}

.footer-note{
  max-width:62ch;
  margin:clamp(30px,4.5vw,48px) 0 0;
  padding:14px 0 14px 18px;
  border-left:2px solid var(--celadon);
  font-size:14px;
  line-height:1.85;
  color:var(--celadon-mist);
}

.footer-bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:10px 26px;
  margin-top:clamp(26px,4vw,38px);
  padding-top:20px;
  border-top:1px solid var(--port-line);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--celadon-mist);
}
.footer-copy,
.footer-legal{margin:0;}
.footer-legal{color:var(--amber);}

/* ---------- 10. 面板 / 章节 / 媒体 / 面包屑 ---------- */
.panel{
  position:relative;
  padding:clamp(20px,3vw,32px);
  background:var(--ink-700);
  border:1px solid var(--port-line);
  color:var(--text);
  clip-path:polygon(0 0,calc(100% - var(--cut)) 0,100% var(--cut),100% 100%,0 100%);
}
.panel--paper{
  background:var(--paper);
  border-color:#C9C2B2;
  color:var(--graphite);
}
.panel--paper h1,
.panel--paper h2,
.panel--paper h3,
.panel--paper h4{color:var(--graphite);}
.panel--paper .eyebrow{color:var(--celadon);}

.rule{
  height:1px;
  background:var(--port-line);
}
.rule--ticks{
  height:12px;
  background:repeating-linear-gradient(90deg,var(--port-line) 0 1px,transparent 1px 14px);
}

.media-frame{
  position:relative;
  display:block;
  width:100%;
  aspect-ratio:16 / 10;
  overflow:hidden;
  border:1px solid var(--port-line);
  clip-path:polygon(0 0,calc(100% - 16px) 0,100% 16px,100% 100%,0 100%);
  background:
    radial-gradient(120% 120% at 12% 0%,rgba(58,125,124,.45),transparent 62%),
    radial-gradient(110% 120% at 94% 102%,rgba(233,180,76,.32),transparent 58%),
    var(--ink-700);
}
.media-frame::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  opacity:.55;
  background-image:
    linear-gradient(rgba(143,189,184,.20) 1px,transparent 1px),
    linear-gradient(90deg,rgba(143,189,184,.20) 1px,transparent 1px);
  background-size:32px 32px;
}
.media-frame > img{
  position:relative;
  z-index:1;
  width:100%;
  height:100%;
  object-fit:cover;
}
.media-frame > figcaption{
  position:absolute;
  z-index:2;
  left:14px;
  bottom:12px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  color:var(--celadon-mist);
}
.media-frame--wide{aspect-ratio:21 / 9;}
.media-frame--square{aspect-ratio:1 / 1;}

@media (max-width:600px){
  .media-frame{aspect-ratio:4 / 3;}
  .media-frame--wide{aspect-ratio:16 / 10;}
  .media-frame--square{aspect-ratio:1 / 1;}
}

.breadcrumbs{
  padding-block:18px 4px;
}
.breadcrumb-list{
  list-style:none;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  margin:0;
  padding:0;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--celadon-mist);
}
.breadcrumb-list li{display:inline-flex;align-items:center;gap:8px;}
.breadcrumb-list li:not(:last-child)::after{
  content:"/";
  color:var(--port-line);
}
.breadcrumb-link{
  color:var(--celadon-mist);
  text-decoration:none;
  transition:color .2s var(--ease);
}
.breadcrumb-link:hover,
.breadcrumb-link:focus-visible{color:var(--amber-soft);}
.breadcrumb-current{color:var(--amber);}

/* ---------- 11. 右侧工具条基础 ---------- */
.tool-rail{
  display:none;
}
@media (min-width:1024px){
  .tool-rail{
    position:fixed;
    top:50%;
    right:0;
    z-index:150;
    transform:translateY(-50%);
    width:64px;
    display:flex;
    flex-direction:column;
    align-items:center;
    gap:12px;
    padding:16px 8px;
    background:var(--ink-900);
    border:1px solid var(--port-line);
    border-right:0;
  }
  .tool-rail__btn{
    display:inline-flex;
    align-items:center;
    justify-content:center;
    width:44px;
    height:44px;
    border:1px solid var(--port-line);
    background:transparent;
    color:var(--celadon-mist);
    font-family:var(--font-mono);
    font-size:11px;
    line-height:1.2;
    text-align:center;
    text-decoration:none;
    cursor:pointer;
    transition:border-color .2s var(--ease),color .2s var(--ease),background .2s var(--ease);
  }
  .tool-rail__btn:hover,
  .tool-rail__btn:focus-visible{
    border-color:var(--amber);
    color:var(--amber-soft);
    background:rgba(233,180,76,.10);
  }
  .tool-rail__count{
    font-family:var(--font-mono);
    font-size:11px;
    letter-spacing:.06em;
    color:var(--amber);
  }
}

/* ---------- 12. 滚动显现 ---------- */
html[data-js="on"] [data-reveal]{
  opacity:0;
  transform:translateY(16px);
}
html[data-js="on"] [data-reveal][data-revealed="true"]{
  opacity:1;
  transform:translateY(0);
  transition:opacity .6s var(--ease),transform .6s var(--ease);
}
html[data-js="on"] [data-reveal][data-revealed="true"] .chapter-num{
  opacity:1;
  transform:scale(1.04);
}

/* ---------- 13. 减少动态 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  *,
  *::before,
  *::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  html[data-js="on"] [data-reveal]{
    opacity:1;
    transform:none;
  }
  .scroll-progress{display:none;}
  .footer-link:hover,
  .btn:hover{transform:none;}
}

/* ---------- 14. 打印 ---------- */
@media print{
  .site-header,
  .site-footer,
  .scroll-progress,
  .skip-link{display:none !important;}
  body{padding:0;background:#fff;color:#000;}
}