/* ========== 01 tokens ========== */
:root{
  --void:#060F1C;
  --stand:#0D1E33;
  --line:#1B3350;
  --turf:#23C97A;
  --volt:#C8FF3D;
  --amber:#FF8A3C;
  --cool:#6FE3FF;
  --history:#A99BFF;
  --paper:#F3F7FB;
  --fog:#93A7BD;
  --body-soft:#C6D5E4;
  --grid:24px;
  --frame:1240px;
  --pad:clamp(16px,4vw,40px);
  --font-sans:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:ui-monospace,"SFMono-Regular","Menlo","Consolas","Liberation Mono","Courier New",monospace;
}

/* ========== 02 reset ========== */
*,*::before,*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%;scroll-behavior:smooth;}
body,h1,h2,h3,h4,p,ul,ol,li,figure,blockquote,dl,dd{margin:0;}
ul,ol{padding:0;list-style:none;}
img,svg{display:block;max-width:100%;height:auto;}
a{color:inherit;text-decoration:none;}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer;}
:focus-visible{outline:2px solid var(--volt);outline-offset:3px;border-radius:2px;}

/* ========== 03 base / 中文排版 ========== */
body{
  background-color:var(--void);
  background-image:
    radial-gradient(1100px 620px at 84% -10%,rgba(35,201,122,.16),transparent 70%),
    radial-gradient(880px 520px at 4% 0%,rgba(111,227,255,.10),transparent 72%),
    linear-gradient(to right,rgba(27,51,80,.42) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(27,51,80,.42) 1px,transparent 1px);
  background-size:auto,auto,var(--grid) var(--grid),var(--grid) var(--grid);
  background-attachment:fixed,fixed,scroll,scroll;
  background-repeat:no-repeat,no-repeat,repeat,repeat;
  color:var(--paper);
  font-family:var(--font-sans);
  font-size:16.5px;
  font-weight:400;
  line-height:1.75;
  letter-spacing:.01em;
  overflow-x:hidden;
}
h1,h2,h3,h4{font-weight:800;line-height:1.2;letter-spacing:-.02em;}
h1{font-size:clamp(30px,4.6vw,52px);}
h2{font-size:clamp(24px,3vw,34px);}
h3{font-size:clamp(19px,2vw,23px);}
p{max-width:38em;}
strong{font-weight:800;color:#fff;}
::selection{background:var(--volt);color:var(--void);}
#main-content{scroll-margin-top:120px;}

/* ========== 04 header ========== */
.masthead{
  position:sticky;top:0;z-index:60;
  background:rgba(6,15,28,.94);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
  box-shadow:0 12px 28px -22px rgba(0,0,0,.95);
}
.skip-link{
  position:absolute;left:16px;top:0;z-index:99;
  transform:translateY(-160%);
  background:var(--volt);color:var(--void);
  font-family:var(--font-mono);font-size:12px;font-weight:700;letter-spacing:.12em;
  padding:10px 14px;border-radius:0 0 3px 3px;
  transition:transform .18s ease;
}
.skip-link:focus{transform:translateY(0);}
.masthead__bar{
  max-width:var(--frame);margin-inline:auto;
  padding:14px var(--pad);
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  transition:padding .24s ease;
}
.masthead[data-scrolled="true"] .masthead__bar{padding-block:8px;}
.brand{display:inline-flex;align-items:baseline;gap:10px;min-width:0;}
.brand__num{
  font-family:var(--font-mono);font-size:12px;font-weight:700;letter-spacing:.06em;
  color:var(--void);background:var(--volt);
  padding:2px 6px;border-radius:2px;transform:translateY(-4px);
}
.brand__name{font-size:clamp(19px,2.4vw,26px);font-weight:800;letter-spacing:-.03em;}
.brand__tag{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.16em;
  color:var(--fog);border-left:1px solid var(--line);padding-left:10px;
}
.masthead__tools{display:flex;align-items:center;gap:10px;flex:none;}
.tool-link{
  display:inline-flex;align-items:center;gap:7px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;
  color:var(--paper);background:var(--stand);
  border:1px solid var(--line);border-radius:2px;
  padding:7px 11px;white-space:nowrap;
  transition:color .2s ease,border-color .2s ease,background .2s ease;
}
.tool-link__num{font-size:10.5px;color:var(--cool);}
.tool-link:hover{border-color:var(--turf);color:var(--volt);}
.tool-link--accent{background:var(--turf);border-color:var(--turf);color:var(--void);font-weight:700;}
.tool-link--accent .tool-link__num{color:rgba(6,15,28,.62);}
.tool-link--accent:hover{background:var(--volt);border-color:var(--volt);color:var(--void);}
.nav-toggle{
  display:none;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.12em;
  color:var(--paper);background:var(--stand);
  border:1px solid var(--line);border-radius:2px;padding:7px 10px;
}
.nav-toggle__bars{display:inline-flex;flex-direction:column;gap:3px;width:16px;}
.nav-toggle__bars i{display:block;height:2px;background:var(--volt);border-radius:1px;transition:transform .2s ease,opacity .2s ease;}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1){transform:translateY(5px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2){opacity:0;}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3){transform:translateY(-5px) rotate(-45deg);}
.nav-rail{
  display:block;
  border-top:1px solid rgba(27,51,80,.75);
  background:linear-gradient(180deg,rgba(13,30,51,.8),rgba(6,15,28,.15));
}
.nav-rail__list{
  max-width:var(--frame);margin-inline:auto;
  padding:0 var(--pad);
  display:flex;align-items:stretch;justify-content:center;gap:4px;
  overflow-x:auto;scrollbar-width:none;
}
.nav-rail__list::-webkit-scrollbar{display:none;}
.nav-rail__link{
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 14px;
  font-family:var(--font-mono);font-size:12.5px;letter-spacing:.1em;
  color:var(--fog);border-bottom:2px solid transparent;white-space:nowrap;
  transition:color .2s ease,border-color .2s ease,background .2s ease;
}
.nav-rail__num{font-size:11px;color:rgba(111,227,255,.6);padding:1px 3px;border-radius:2px;transition:color .2s ease,background .2s ease;}
.nav-rail__link:hover{color:var(--paper);border-bottom-color:var(--turf);}
.nav-rail__link[aria-current="page"]{color:#fff;border-bottom-color:var(--volt);}
.nav-rail__link[aria-current="page"] .nav-rail__num{background:var(--volt);color:var(--void);font-weight:700;}
.masthead[data-scrolled="true"] .nav-rail__link{padding-block:8px;font-size:12px;}
.scroll-meter{height:2px;background:rgba(27,51,80,.85);overflow:hidden;}
.scroll-meter__fill{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--turf),var(--cool) 45%,var(--volt));
  transition:width .1s linear;
}

/* ========== 05 footer ========== */
.site-foot{
  position:relative;
  margin-top:clamp(48px,8vw,96px);
  background:linear-gradient(180deg,rgba(13,30,51,.92),rgba(6,15,28,1));
  border-top:1px solid var(--line);
}
.site-foot::before{
  content:"";position:absolute;left:0;right:0;top:0;height:3px;
  background:linear-gradient(90deg,var(--turf),var(--cool) 34%,var(--volt) 68%,var(--amber));
}
.site-foot__grid{
  max-width:var(--frame);margin-inline:auto;
  padding:clamp(28px,5vw,52px) var(--pad) 0;
  display:grid;gap:clamp(22px,3vw,36px);
  grid-template-columns:1.5fr 1fr 1fr .8fr;
  align-items:start;
}
.site-foot__brand{display:flex;flex-direction:column;align-items:flex-start;gap:14px;}
.brand--foot .brand__name{font-size:20px;}
.site-foot__note{font-size:13.5px;line-height:1.85;color:var(--fog);max-width:26em;}
.foot-col__head{
  font-family:var(--font-mono);font-size:11px;font-weight:700;
  letter-spacing:.2em;text-transform:uppercase;color:var(--cool);
  padding-bottom:8px;margin-bottom:14px;border-bottom:1px solid var(--line);
}
.foot-col__list li + li{margin-top:9px;}
.foot-col__link{
  display:inline-flex;align-items:flex-start;gap:8px;
  font-size:14px;color:var(--fog);
  transition:color .2s ease;
}
.foot-col__link:hover{color:var(--volt);}
.foot-col__num{font-family:var(--font-mono);font-size:10.5px;letter-spacing:.08em;color:rgba(111,227,255,.55);padding-top:4px;}
.site-foot__meta{
  max-width:var(--frame);margin-inline:auto;
  margin-top:clamp(24px,4vw,40px);
  padding:20px var(--pad) 32px;
  border-top:1px solid var(--line);
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px 26px;
}
.foot-contact,.foot-copy{
  font-family:var(--font-mono);font-size:11.5px;line-height:1.9;letter-spacing:.05em;color:var(--fog);
  max-width:60ch;
}
.to-top{
  display:inline-flex;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.14em;
  color:var(--paper);background:var(--stand);
  border:1px solid var(--line);border-radius:2px;padding:8px 12px;
  transition:color .2s ease,border-color .2s ease,transform .2s ease;
}
.to-top[hidden]{display:none;}
.to-top:hover{border-color:var(--volt);color:var(--volt);transform:translateY(-2px);}

/* ========== 06 通用布局 ========== */
.container{width:100%;max-width:var(--frame);margin-inline:auto;padding-inline:var(--pad);}
.split{
  display:grid;gap:clamp(20px,3vw,40px);
  grid-template-columns:minmax(0,5fr) minmax(0,7fr);
  align-items:start;
}
.split__rail{
  position:relative;min-width:0;
  padding-right:clamp(16px,2vw,28px);
  border-right:1px solid var(--line);
}
.split__main{min-width:0;}
.seam{display:none;}
.section{padding-block:clamp(36px,6vw,72px);border-top:1px solid var(--line);}
.section__head{display:flex;flex-wrap:wrap;align-items:baseline;gap:12px 20px;margin-bottom:clamp(18px,3vw,32px);}
.section__num{
  font-family:var(--font-mono);font-weight:700;
  font-size:clamp(30px,4.6vw,48px);line-height:.9;letter-spacing:-.04em;
  color:var(--turf);
}
.rule{height:1px;border:0;background:var(--line);margin-block:clamp(24px,4vw,48px);}

/* ========== 07 文字组件 ========== */
.eyebrow{
  display:inline-flex;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.22em;text-transform:uppercase;
  color:var(--cool);
}
.eyebrow::before{content:"";width:8px;height:8px;background:var(--volt);display:block;flex:none;}
.lede{font-size:clamp(17px,1.6vw,19px);line-height:1.8;color:var(--body-soft);max-width:34em;}
.prose{font-size:16px;line-height:1.85;color:var(--body-soft);}
.prose p + p{margin-top:1em;}
.num-hero{
  font-family:var(--font-mono);font-weight:700;
  font-size:clamp(64px,11vw,120px);line-height:.82;letter-spacing:-.05em;
  color:var(--volt);font-variant-numeric:tabular-nums;
}

/* ========== 08 面包屑与章节索引 ========== */
.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:6px;
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.1em;
  color:var(--fog);padding-block:18px;
}
.breadcrumb a{color:var(--fog);transition:color .2s ease;}
.breadcrumb a:hover{color:var(--volt);}
.breadcrumb__sep{color:var(--line);}
.breadcrumb [aria-current="page"]{color:var(--paper);}
.spy-link{
  display:flex;align-items:center;gap:10px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.12em;
  color:var(--fog);padding:8px 0;
  border-bottom:1px solid rgba(27,51,80,.55);
  transition:color .2s ease;
}
.spy-link:hover{color:var(--paper);}
.spy-link[data-active]{color:var(--volt);}
.spy-link[data-active]::after{content:"";margin-left:auto;width:6px;height:6px;background:var(--volt);flex:none;}

/* ========== 09 卡片 / 标签 / 按钮 ========== */
.card{
  position:relative;
  background:linear-gradient(180deg,rgba(13,30,51,.96),rgba(13,30,51,.72));
  border:1px solid var(--line);border-radius:3px;
  padding:clamp(16px,2.4vw,26px);
  box-shadow:0 20px 36px -30px rgba(0,0,0,.95);
  min-width:0;
}
.card::before{
  content:"";position:absolute;left:0;top:0;width:100%;height:2px;
  background:linear-gradient(90deg,var(--turf),transparent 72%);
}
.card--offset{margin-top:clamp(16px,3vw,48px);}
.card-grid{display:grid;gap:clamp(14px,2vw,24px);grid-template-columns:repeat(auto-fit,minmax(240px,1fr));}
.card__num{
  display:block;margin-bottom:10px;
  font-family:var(--font-mono);font-weight:700;
  font-size:clamp(28px,4vw,44px);line-height:1;letter-spacing:-.04em;
  color:var(--turf);
}
.card__title{font-size:18px;margin-bottom:8px;letter-spacing:-.01em;}
.card__text{font-size:14.5px;line-height:1.8;color:var(--fog);}
.tag{
  display:inline-flex;align-items:center;gap:6px;
  font-family:var(--font-mono);font-size:10.5px;letter-spacing:.16em;text-transform:uppercase;
  padding:4px 9px;border:1px solid var(--line);border-radius:2px;
  color:var(--fog);background:rgba(13,30,51,.8);white-space:nowrap;
}
.tag--volt{background:var(--volt);border-color:var(--volt);color:var(--void);font-weight:700;}
.tag--amber{background:var(--amber);border-color:var(--amber);color:var(--void);font-weight:700;}
.tag--cool{color:var(--cool);border-color:rgba(111,227,255,.45);}
.tag--history{color:var(--history);border-color:rgba(169,155,255,.45);}
.btn{
  display:inline-flex;align-items:center;gap:9px;
  font-family:var(--font-mono);font-size:12.5px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;
  padding:13px 20px;border:1px solid transparent;border-radius:2px;
  transition:transform .2s ease,background .2s ease,color .2s ease,border-color .2s ease;
}
.btn:hover{transform:translateY(-2px);}
.btn__num{opacity:.62;}
.btn--primary{background:var(--turf);border-color:var(--turf);color:var(--void);}
.btn--primary:hover{background:var(--volt);border-color:var(--volt);}
.btn--ghost{background:transparent;border-color:var(--line);color:var(--paper);}
.btn--ghost:hover{border-color:var(--volt);color:var(--volt);}

/* ========== 10 数据组件 ========== */
.stat{display:flex;flex-direction:column;gap:4px;}
.stat__value{
  font-family:var(--font-mono);font-weight:700;
  font-size:clamp(30px,4.4vw,44px);line-height:1;letter-spacing:-.03em;
  color:var(--volt);font-variant-numeric:tabular-nums;
}
.stat__value--turf{color:var(--turf);}
.stat__label{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--fog);
}
.data-bar{position:relative;height:10px;background:rgba(27,51,80,.9);border-radius:2px;overflow:hidden;}
.data-bar__fill{
  display:block;height:100%;width:var(--value,50%);
  background:linear-gradient(90deg,var(--turf),var(--volt));
  transition:width .5s ease;
}
.data-bar__fill--alt{background:linear-gradient(90deg,var(--cool),var(--history));}

/* ========== 11 图片容器 ========== */
.media-frame{
  position:relative;overflow:hidden;
  border:1px solid var(--line);border-radius:3px;
  background:var(--stand);aspect-ratio:16/9;
}
.media-frame--tall{aspect-ratio:4/5;}
.media-frame--wide{aspect-ratio:21/9;}
.media-frame__img{
  width:100%;height:100%;object-fit:cover;
  filter:saturate(.9) contrast(1.06) brightness(.86);
}
.media-frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:
    linear-gradient(to right,rgba(6,15,28,.4) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(6,15,28,.4) 1px,transparent 1px);
  background-size:32px 32px;
}
.media-frame__cap{
  position:absolute;left:0;bottom:0;z-index:2;
  font-family:var(--font-mono);font-size:10.5px;letter-spacing:.14em;text-transform:uppercase;
  color:var(--fog);background:rgba(6,15,28,.85);
  padding:5px 9px;border-top:1px solid var(--line);border-right:1px solid var(--line);
}

/* ========== 12 响应式 ========== */
@media (min-width:1100px){
  .seam{
    display:flex;flex-direction:column;align-items:center;gap:18px;
    font-family:var(--font-mono);font-size:11px;letter-spacing:.2em;
    color:rgba(147,167,189,.6);
  }
  .seam::before{content:"";width:1px;height:64px;background:linear-gradient(180deg,transparent,var(--turf));}
}
@media (max-width:1099px){
  .site-foot__grid{grid-template-columns:1.3fr 1fr 1fr;}
  .site-foot__grid > .foot-col:last-child{grid-column:1 / -1;}
  .site-foot__grid > .foot-col:last-child .foot-col__list{display:flex;flex-wrap:wrap;gap:8px 24px;}
  .site-foot__grid > .foot-col:last-child .foot-col__list li + li{margin-top:0;}
}
@media (max-width:899px){
  .masthead__bar{padding-block:10px;}
  .brand__tag{display:none;}
  .tool-link--quiet{display:none;}
  .nav-toggle{display:inline-flex;}
  .nav-rail{display:none;border-top:1px solid var(--line);}
  .nav-rail[data-open]{display:block;animation:rail-in .22s ease-out;}
  .nav-rail__list{flex-direction:column;align-items:stretch;gap:0;padding-block:6px;max-height:min(72vh,540px);overflow-y:auto;}
  .nav-rail__item{border-bottom:1px solid rgba(27,51,80,.6);}
  .nav-rail__item:last-child{border-bottom:0;}
  .nav-rail__link{width:100%;justify-content:flex-start;padding:13px var(--pad);font-size:13.5px;border-bottom:0;}
  .nav-rail__link[aria-current="page"]{background:rgba(200,255,61,.07);}
  .nav-rail__num{font-size:12px;min-width:2.4em;}
  .masthead[data-scrolled="true"] .nav-rail__link{padding-block:13px;font-size:13.5px;}
  .split{grid-template-columns:1fr;}
  .split__rail{border-right:0;border-bottom:1px solid var(--line);padding-right:0;padding-bottom:22px;}
  .site-foot__grid{grid-template-columns:1fr 1fr;}
  .site-foot__brand{grid-column:1 / -1;}
  .site-foot__meta{flex-direction:column;align-items:flex-start;}
}
@media (max-width:560px){
  .site-foot__grid{grid-template-columns:1fr;}
  .site-foot__grid > .foot-col:last-child{grid-column:auto;}
  .tool-link--accent{padding:6px 9px;font-size:11px;}
  .brand__name{font-size:18px;}
}

/* ========== 13 动效与可访问性 ========== */
@keyframes rail-in{from{opacity:0;transform:translateY(-6px);}to{opacity:1;transform:translateY(0);}}
@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;
  }
  .btn:hover,.to-top:hover{transform:none;}
}