/* ===== 1. 变量 ===== */
:root{
  --bg-deep:#070B1A;
  --bg-map:#0E1730;
  --bg-panel:#16234A;
  --cyan:#38F0D2;
  --blue:#4C8DFF;
  --orange:#FFA23A;
  --violet:#7B4DFF;
  --magenta:#E23F87;
  --ink:#EAF1FF;
  --ink-2:#9AAAC9;
  --line:#1E2C50;
  --alert:#FF6B6B;
  --rail-w:88px;
  --topbar-h:58px;
  --notch:14px;
  --font-display:"Barlow Condensed","Oswald","Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  --font-body:"Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --ease:180ms cubic-bezier(.2,.7,.3,1);
}

/* ===== 2. Reset ===== */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
h1,h2,h3,h4,h5,p,ul,ol,figure,blockquote{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,video{display:block;max-width:100%}
a{color:var(--blue);text-decoration:none;transition:color var(--ease)}
a:hover{color:var(--cyan)}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
::selection{background:var(--cyan);color:#04101F}

/* ===== 3. 基础排版 ===== */
body{
  margin:0;
  min-height:100vh;
  background-color:var(--bg-deep);
  background-image:
    linear-gradient(to right,rgba(30,44,80,.45) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(30,44,80,.45) 1px,transparent 1px);
  background-size:72px 72px;
  color:var(--ink);
  font-family:var(--font-body);
  font-size:16px;
  font-weight:400;
  line-height:1.65;
  padding-top:var(--topbar-h);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
@media (min-width:901px){
  body{padding-top:0;padding-left:var(--rail-w)}
}
body.nav-open{overflow:hidden}

h1,h2,h3,h4,h5{
  font-family:var(--font-display);
  font-weight:800;
  letter-spacing:-.02em;
  line-height:1.08;
  color:var(--ink);
}
h1{font-size:clamp(34px,7vw,64px)}
h2{font-size:clamp(26px,4.2vw,40px)}
h3{font-size:clamp(19px,2.6px + 2vw,24px)}
h4{font-size:18px;letter-spacing:0}
p{max-width:38em}
strong{font-weight:700;color:var(--ink)}

#main-content{display:block;outline:none}

/* ===== 4. 工具类 ===== */
.container{
  width:100%;
  max-width:1180px;
  margin:0 auto;
  padding:0 20px;
}
@media (min-width:901px){.container{padding:0 32px}}

.eyebrow{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.22em;
  line-height:1.4;
  color:var(--cyan);
}
.num{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  letter-spacing:-.01em;
}
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:3px 9px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  line-height:1.6;
  color:var(--ink-2);
  border:1px solid var(--line);
  background:rgba(22,35,74,.5);
}
.tag--hot{border-color:var(--orange);color:var(--orange)}
.tag--live{border-color:var(--magenta);color:var(--magenta)}

/* ===== 5. 按钮 ===== */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.5em;
  font-family:var(--font-display);
  font-weight:700;
  font-size:14px;
  letter-spacing:.04em;
  line-height:1.25;
  padding:.75em 1.2em;
  color:var(--ink);
  background:rgba(22,35,74,.65);
  border:1px solid var(--line);
  text-align:center;
  text-decoration:none;
  transition:color var(--ease),background-color var(--ease),border-color var(--ease),transform var(--ease);
}
.btn:hover{color:var(--ink);border-color:var(--blue);background:rgba(76,141,255,.16)}
.btn:active{transform:translateY(1px)}
.btn:focus-visible{outline:2px solid var(--cyan);outline-offset:3px}
.btn--primary{background:var(--cyan);border-color:var(--cyan);color:#04101F}
.btn--primary:hover{background:#5EF7DD;border-color:#5EF7DD;color:#04101F}
.btn--ghost{background:transparent}
.btn--block{display:flex;width:100%}

/* ===== 6. 面板 / 图片容器 ===== */
.panel{
  position:relative;
  background:var(--bg-panel);
  border:1px solid var(--line);
  clip-path:polygon(0 0,calc(100% - var(--notch)) 0,100% var(--notch),100% 100%,0 100%);
}

.media-frame{
  position:relative;
  overflow:hidden;
  border:1px solid var(--line);
  background-color:#0B1224;
  background-image:linear-gradient(118deg,rgba(76,141,255,.22),rgba(123,77,255,.18) 46%,rgba(226,63,135,.16));
  clip-path:polygon(0 0,calc(100% - 18px) 0,100% 18px,100% 100%,0 100%);
}
.media-frame img{
  width:100%;
  height:100%;
  object-fit:cover;
  display:block;
}
.media-frame::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background:linear-gradient(180deg,rgba(14,23,48,.10),rgba(7,11,26,.72));
  box-shadow:inset 0 0 0 1px rgba(56,240,210,.16);
}
.media-frame--ratio{aspect-ratio:16/10}
@media (max-width:640px){.media-frame--ratio{aspect-ratio:4/3}}

/* ===== 7. 章节数字 ===== */
.section-num{
  display:block;
  font-family:var(--font-mono);
  font-weight:700;
  font-size:clamp(48px,9vw,96px);
  line-height:.85;
  letter-spacing:-.03em;
  color:rgba(30,44,80,.95);
}
@supports (-webkit-text-stroke:1px red){
  .section-num{color:transparent;-webkit-text-stroke:1px var(--line)}
}

/* ===== 8. 面包屑 ===== */
.breadcrumb{margin-top:22px}
.breadcrumb__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  font-size:12px;
  letter-spacing:.06em;
  color:var(--ink-2);
}
.breadcrumb__list li{display:flex;align-items:center}
.breadcrumb__list li + li::before{content:"/";margin:0 8px;color:var(--line)}
.breadcrumb__list a{color:var(--ink-2)}
.breadcrumb__list a:hover{color:var(--cyan)}
.breadcrumb__list [aria-current="page"]{color:var(--ink)}

/* ===== 9. 分段切换 ===== */
.tabs{--tab-gap:6px}
.tablist{
  display:flex;
  gap:var(--tab-gap);
  overflow-x:auto;
  border-bottom:1px solid var(--line);
  scrollbar-width:thin;
}
.tablist [role="tab"]{
  flex:0 0 auto;
  padding:10px 16px;
  font-family:var(--font-display);
  font-weight:700;
  font-size:14px;
  letter-spacing:.04em;
  color:var(--ink-2);
  background:transparent;
  border:1px solid transparent;
  border-bottom:0;
  transition:color var(--ease),background-color var(--ease),border-color var(--ease);
}
.tablist [role="tab"]:hover{color:var(--ink);background:rgba(76,141,255,.12)}
.tablist [role="tab"]:focus-visible{outline:2px solid var(--cyan);outline-offset:-2px}
.tablist [role="tab"][aria-selected="true"]{
  color:#04101F;
  background:var(--cyan);
  border-color:var(--cyan);
}
.tabpanel{padding-top:22px}
.tabpanel[hidden]{display:none}

/* ===== 10. 跳转链接 ===== */
.skip-link{
  position:fixed;
  top:10px;
  left:12px;
  z-index:200;
  padding:.65em 1.1em;
  font-family:var(--font-display);
  font-weight:700;
  font-size:14px;
  letter-spacing:.04em;
  color:#04101F;
  background:var(--cyan);
  transform:translateY(-180%);
  transition:transform var(--ease);
}
@media (min-width:901px){.skip-link{left:calc(var(--rail-w) + 14px)}}
.skip-link:focus{transform:translateY(0);color:#04101F}

/* ===== 11. 头部 / 侧边轨道 ===== */
.site-header{
  position:fixed;
  top:0;
  left:0;
  right:0;
  height:var(--topbar-h);
  z-index:80;
  background:linear-gradient(180deg,#0E1730 0%,#0A1024 100%);
  border-bottom:1px solid var(--line);
}
.rail__progress{
  position:absolute;
  left:0;
  bottom:-1px;
  width:100%;
  height:2px;
  background:linear-gradient(90deg,var(--cyan),var(--blue) 48%,var(--violet) 74%,var(--magenta));
  transform:scaleX(var(--scroll,0));
  transform-origin:left center;
  pointer-events:none;
}
.rail{
  position:relative;
  display:flex;
  flex-direction:row;
  align-items:center;
  justify-content:space-between;
  height:100%;
  padding:0 14px 0 16px;
}

.rail__brand{
  display:flex;
  flex-direction:row;
  align-items:center;
  gap:9px;
  color:var(--ink);
  text-decoration:none;
}
.rail__brand:hover{color:var(--cyan)}
.rail__mark{
  flex:none;
  width:26px;
  height:26px;
  background:linear-gradient(140deg,var(--cyan),var(--blue) 55%,var(--violet));
  clip-path:polygon(0 0,100% 0,100% 64%,64% 100%,0 100%);
  position:relative;
}
.rail__mark::after{
  content:"";
  position:absolute;
  inset:7px;
  background:rgba(4,16,31,.72);
  clip-path:polygon(0 0,100% 0,100% 64%,64% 100%,0 100%);
}
.rail__name{
  font-family:var(--font-display);
  font-weight:800;
  font-size:16px;
  letter-spacing:.04em;
  line-height:1;
}

/* 移动抽屉按钮 */
.nav-toggle{
  display:inline-flex;
  align-items:center;
  gap:9px;
  padding:8px 10px;
  color:var(--ink);
  border:1px solid var(--line);
  font-family:var(--font-display);
  font-size:13px;
  font-weight:700;
  letter-spacing:.08em;
  transition:border-color var(--ease),color var(--ease);
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan)}
.nav-toggle:focus-visible{outline:2px solid var(--cyan);outline-offset:2px}
.nav-toggle__bars{display:flex;flex-direction:column;gap:3px;width:16px}
.nav-toggle__bars span{
  display:block;
  height:2px;
  background:currentColor;
  transition:transform var(--ease),opacity var(--ease);
}
.site-header[data-open] .nav-toggle__bars span:nth-child(1){transform:translateY(5px) rotate(45deg)}
.site-header[data-open] .nav-toggle__bars span:nth-child(2){opacity:0}
.site-header[data-open] .nav-toggle__bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg)}

/* 移动抽屉 */
.site-nav{
  position:fixed;
  top:var(--topbar-h);
  right:0;
  bottom:0;
  z-index:90;
  display:flex;
  flex-direction:column;
  width:min(88vw,360px);
  padding:20px 20px 28px;
  background:linear-gradient(180deg,#101A36 0%,#070B1A 100%);
  border-left:1px solid var(--line);
  overflow-y:auto;
  visibility:hidden;
  transform:translateX(102%);
  transition:transform 220ms cubic-bezier(.2,.7,.3,1),visibility 220ms;
}
.site-header[data-open] .site-nav{
  visibility:visible;
  transform:translateX(0);
}
.site-nav__list{
  display:flex;
  flex-direction:column;
  align-items:stretch;
  gap:0;
  flex:1;
}
.site-nav__list li{border-bottom:1px solid var(--line)}
.site-nav__list a{
  display:flex;
  align-items:center;
  gap:12px;
  padding:14px 12px;
  font-family:var(--font-display);
  font-size:17px;
  font-weight:700;
  letter-spacing:.02em;
  line-height:1.3;
  color:var(--ink-2);
  transition:color var(--ease),background-color var(--ease);
}
.site-nav__list a:hover{color:var(--cyan);background:rgba(56,240,210,.07)}
.site-nav__list a:focus-visible{outline:2px solid var(--cyan);outline-offset:-3px}
.site-nav__list a[aria-current="page"]{
  color:var(--cyan);
  background:rgba(56,240,210,.09);
  box-shadow:inset 3px 0 0 var(--cyan);
}
.rail__cta{
  display:flex;
  flex-direction:column;
  align-items:stretch;
  gap:10px;
  margin-top:auto;
  padding-top:20px;
}
.rail__cta .btn{
  width:100%;
  padding:.9em 1em;
  font-size:15px;
}

/* ===== 12. 桌面端轨道形态 ===== */
@media (min-width:901px){
  .site-header{
    right:auto;
    bottom:0;
    width:var(--rail-w);
    height:auto;
    border-bottom:0;
    border-right:1px solid var(--line);
  }
  .rail__progress{
    top:0;
    bottom:auto;
    left:auto;
    right:-1px;
    width:2px;
    height:calc(var(--scroll,0) * 100%);
    transform:none;
    background:linear-gradient(180deg,var(--cyan),var(--blue) 52%,var(--violet) 78%,var(--magenta));
  }
  .rail{
    flex-direction:column;
    align-items:center;
    justify-content:flex-start;
    height:100%;
    padding:18px 0 16px;
  }
  .rail__brand{
    flex-direction:column;
    gap:10px;
    padding:4px 0;
  }
  .rail__mark{width:34px;height:34px}
  .rail__mark::after{inset:9px}
  .rail__name{
    writing-mode:vertical-rl;
    text-orientation:upright;
    font-size:15px;
    letter-spacing:.16em;
  }
  .nav-toggle{display:none}
  .site-nav{
    position:static;
    flex:1;
    display:flex;
    width:100%;
    min-height:0;
    padding:14px 0 0;
    background:none;
    border-left:0;
    overflow:visible;
    visibility:visible;
    transform:none;
  }
  .site-nav__list{
    flex:1;
    flex-direction:column;
    align-items:center;
    justify-content:center;
    gap:4px;
    min-height:0;
    overflow-y:auto;
    scrollbar-width:thin;
  }
  .site-nav__list li{border-bottom:0}
  .site-nav__list a{
    writing-mode:vertical-rl;
    text-orientation:upright;
    display:block;
    padding:10px 7px;
    font-size:13px;
    font-weight:700;
    letter-spacing:.12em;
    color:var(--ink-2);
    background:none;
  }
  .site-nav__list a:hover{background:rgba(56,240,210,.08)}
  .site-nav__list a[aria-current="page"]{
    background:rgba(56,240,210,.10);
    box-shadow:inset 2px 0 0 var(--cyan);
  }
  .rail__cta{
    align-items:center;
    margin-top:12px;
    padding-top:0;
  }
  .rail__cta .btn{
    writing-mode:vertical-rl;
    text-orientation:upright;
    width:auto;
    padding:16px 9px;
    font-size:12px;
    letter-spacing:.18em;
  }
}

/* ===== 13. 页脚 ===== */
.site-footer{
  position:relative;
  margin-top:88px;
  background:linear-gradient(180deg,var(--bg-map) 0%,var(--bg-deep) 100%);
  border-top:1px solid var(--line);
}
.footer-stripe{
  height:3px;
  background:linear-gradient(90deg,var(--cyan),var(--blue) 30%,var(--violet) 66%,var(--magenta));
}
.footer-inner{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:34px;
  max-width:1200px;
  margin:0 auto;
  padding:48px 20px 26px;
}
.footer-brand__name{
  display:flex;
  align-items:center;
  font-family:var(--font-display);
  font-weight:800;
  font-size:22px;
  letter-spacing:.02em;
  color:var(--ink);
}
.footer-brand__mark{
  display:inline-block;
  width:14px;
  height:14px;
  margin-right:9px;
  background:linear-gradient(135deg,var(--cyan),var(--blue));
  clip-path:polygon(0 0,100% 0,100% 60%,60% 100%,0 100%);
}
.footer-brand__tag{
  margin-top:10px;
  font-size:15px;
  color:var(--ink-2);
  max-width:24em;
}
.footer-brand__meta{
  margin-top:12px;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--ink-2);
}
.footer-brand__meta .num{color:var(--orange)}

.footer-nav{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:24px 28px;
}
@media (min-width:760px){
  .footer-nav{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (min-width:1040px){
  .footer-nav{grid-template-columns:repeat(3,minmax(0,1fr))}
}
.footer-col__title{
  margin-bottom:14px;
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:500;
  letter-spacing:.2em;
  color:var(--cyan);
}
.footer-col__title::before{
  content:"";
  display:inline-block;
  width:14px;
  height:1px;
  margin-right:8px;
  vertical-align:middle;
  background:var(--cyan);
}
.footer-list a{
  display:inline-block;
  padding:5px 0;
  font-size:14px;
  color:var(--ink-2);
}
.footer-list a:hover{color:var(--ink)}
.footer-list a:focus-visible{outline:2px solid var(--cyan);outline-offset:2px}

.footer-contact{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:16px 24px;
  padding-top:24px;
  border-top:1px solid var(--line);
}
@media (min-width:640px){
  .footer-contact{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (min-width:1040px){
  .footer-contact{grid-template-columns:repeat(4,minmax(0,1fr))}
}
.footer-contact__item{
  display:flex;
  flex-direction:column;
  gap:4px;
  max-width:none;
  min-width:0;
}
.footer-contact__key{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  color:var(--cyan);
}
.footer-contact__val{
  font-size:14px;
  line-height:1.5;
  color:var(--ink);
  word-break:break-word;
}
.footer-contact__val.num{color:var(--orange)}

.footer-bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding-top:20px;
  border-top:1px solid var(--line);
}
.footer-bottom__legal{
  font-size:12px;
  letter-spacing:.02em;
  color:var(--ink-2);
  max-width:none;
}
.to-top{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:8px 14px;
  font-family:var(--font-display);
  font-size:12px;
  font-weight:700;
  letter-spacing:.12em;
  color:var(--ink-2);
  border:1px solid var(--line);
  transition:color var(--ease),border-color var(--ease),background-color var(--ease);
}
.to-top:hover{color:var(--cyan);border-color:var(--cyan);background:rgba(56,240,210,.08)}
.to-top:focus-visible{outline:2px solid var(--cyan);outline-offset:3px}

@media (min-width:760px){
  .footer-inner{
    grid-template-columns:minmax(0,.9fr) minmax(0,1.6fr);
    gap:34px 48px;
    padding:56px 32px 28px;
  }
  .footer-contact{grid-column:1 / -1}
  .footer-bottom{grid-column:1 / -1}
}

/* ===== 14. 显现动画 ===== */
.js-reveal [data-reveal]{
  opacity:0;
  transform:translateY(12px);
  transition:opacity 380ms ease,transform 380ms ease;
}
.js-reveal [data-reveal].is-in{
  opacity:1;
  transform:none;
}

/* ===== 15. 动效降级 ===== */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .js-reveal [data-reveal]{opacity:1;transform:none;transition:none}
  .site-nav{transition:none}
}