/* =========================================================
   天天娱乐会馆 · fast-tt.com.cn
   /assets/site.css —— 共享外壳与基础组件（WELCOME V4）
   深空蓝 × 电光青 × 暖金 / 展览画册式框架
   ========================================================= */

/* ---------- 1. 变量 ---------- */
:root{
  --ink-0:#050B1A;
  --ink-1:#0B1730;
  --ink-2:#12224A;
  --line:#24365F;
  --cyan:#35E6D2;
  --cyan-soft:#8FF4EA;
  --gold:#F2B33D;
  --gold-deep:#C98A1F;
  --text:#EAF2FF;
  --text-2:#A9B8D6;
  --text-3:#6E7F9F;
  --ok:#4AD295;

  --font-head:'Noto Sans SC','Source Han Sans SC','HarmonyOS Sans SC',sans-serif;
  --font-latin:'Space Grotesk','Chakra Petch',sans-serif;
  --font-body:'Noto Sans SC','PingFang SC','Microsoft YaHei',sans-serif;
  --font-mono:'JetBrains Mono','IBM Plex Mono','Sarasa Mono SC',monospace;

  --frame-x:clamp(16px,4vw,56px);
  --frame-max:1480px;
  --rail:64px;
  --header-h:78px;
  --radius:16px;
  --ease:.24s cubic-bezier(.22,.61,.36,1);
}

*,*::before,*::after{box-sizing:border-box}

html{
  -webkit-text-size-adjust:100%;
  text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:128px;
}

body{
  margin:0;
  background-color:var(--ink-0);
  color:var(--text);
  font-family:var(--font-body);
  font-size:16px;
  font-weight:400;
  line-height:1.75;
  letter-spacing:.01em;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

/* 全局纵深光晕：背景分区，让深空底色不呆板 */
body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:-1;
  pointer-events:none;
  background:
    radial-gradient(920px 540px at 84% -8%, rgba(53,230,210,.14), transparent 66%),
    radial-gradient(720px 480px at 4% 26%, rgba(242,179,61,.07), transparent 70%),
    radial-gradient(1000px 600px at 50% 118%, rgba(53,230,210,.08), transparent 72%),
    linear-gradient(180deg,#050B1A 0%,#071027 48%,#050B1A 100%);
}

img,svg,video{max-width:100%}
ul,ol{list-style:none}
button{font:inherit}

/* ---------- 2. 中文排版 ---------- */
h1,h2,h3,h4,h5{
  margin:0;
  font-family:var(--font-head);
  font-weight:900;
  line-height:1.16;
  letter-spacing:.01em;
  color:var(--text);
}
h1{font-size:clamp(32px,5.2vw,66px);letter-spacing:.005em}
h2{font-size:clamp(25px,3.4vw,42px)}
h3{font-size:clamp(18px,2vw,24px);font-weight:800}
h4{font-size:clamp(16px,1.6vw,19px);font-weight:800}
p{margin:0 0 1.05em;color:var(--text-2);max-width:38em}
p:last-child{margin-bottom:0}
strong{color:var(--text);font-weight:700}
small{font-size:12.5px;color:var(--text-3)}

a{color:var(--cyan);text-decoration-thickness:1px;text-underline-offset:3px}
a:hover{color:var(--cyan-soft)}

.mono,.stat-value,.timeline-meta,.sub-version{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  font-feature-settings:"tnum" 1;
}

/* ---------- 3. 焦点与可访问性 ---------- */
:focus{outline:none}
:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:3px;
  border-radius:4px;
}
.btn:focus-visible{outline-color:var(--gold);outline-offset:3px}
.nav-link:focus-visible{outline-color:var(--gold)}

.skip-link{
  position:fixed;
  left:0;
  top:0;
  z-index:400;
  transform:translateY(-140%);
  padding:12px 22px;
  background:var(--gold);
  color:#08111F;
  font-weight:800;
  font-size:14px;
  text-decoration:none;
  border-radius:0 0 12px 0;
  transition:transform .2s ease;
}
.skip-link:focus{transform:translateY(0);color:#08111F}

/* ---------- 4. 顶部框架导航 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:300;
  background:rgba(5,11,26,.94);
  border-bottom:1px solid var(--line);
}
.site-header::before{
  content:"";
  position:absolute;
  left:0;right:0;top:0;
  height:2px;
  background:linear-gradient(90deg,var(--cyan) 0%,rgba(53,230,210,0) 42%,rgba(242,179,61,0) 62%,var(--gold) 100%);
  pointer-events:none;
}

.scroll-progress{
  position:fixed;
  left:0;top:0;
  width:100%;
  height:2px;
  z-index:320;
  background:linear-gradient(90deg,var(--cyan),var(--gold));
  transform:scaleX(0);
  transform-origin:0 50%;
  pointer-events:none;
  will-change:transform;
}

.header-frame{
  width:100%;
  max-width:var(--frame-max);
  margin:0 auto;
  padding:0 var(--frame-x);
}

.header-top{
  display:flex;
  align-items:center;
  gap:clamp(14px,2vw,34px);
  min-height:var(--header-h);
  transition:min-height var(--ease);
}
.site-header[data-shrink="true"] .header-top{min-height:60px}

/* 品牌 */
.brand{
  display:inline-flex;
  align-items:center;
  gap:12px;
  flex:0 0 auto;
  text-decoration:none;
  color:var(--text);
}
.brand:hover{color:var(--text)}
.brand-mark{
  position:relative;
  display:block;
  width:36px;
  height:36px;
  border:1px solid var(--line);
  border-radius:11px;
  background:linear-gradient(150deg,rgba(53,230,210,.22),rgba(5,11,26,0) 72%);
  flex:0 0 auto;
  transition:border-color var(--ease),transform var(--ease);
}
.brand-mark::before{
  content:"";
  position:absolute;
  left:9px;top:9px;
  width:14px;height:14px;
  border-radius:50%;
  background:var(--cyan);
  box-shadow:0 0 0 4px rgba(53,230,210,.14),0 0 16px rgba(53,230,210,.55);
}
.brand-mark::after{
  content:"";
  position:absolute;
  right:6px;bottom:6px;
  width:8px;height:8px;
  border-radius:2px;
  background:var(--gold);
}
.brand:hover .brand-mark{border-color:var(--cyan);transform:translateY(-2px)}
.brand-text{display:block;min-width:0}
.brand-name{
  display:block;
  font-family:var(--font-head);
  font-weight:900;
  font-size:17px;
  line-height:1.25;
  letter-spacing:.06em;
  white-space:nowrap;
}
.brand-line{
  display:block;
  font-size:11.5px;
  line-height:1.4;
  letter-spacing:.14em;
  color:var(--text-3);
  white-space:nowrap;
  transition:opacity var(--ease);
}
.site-header[data-shrink="true"] .brand-line{opacity:0}

/* 主导航 */
.primary-nav{
  margin-left:auto;
  display:flex;
  min-width:0;
}
.nav-list{
  display:flex;
  align-items:center;
  gap:clamp(0px,.5vw,8px);
  margin:0;
  padding:0;
}
.nav-item{display:block}
.nav-link{
  display:inline-block;
  padding:8px 12px;
  font-size:15px;
  line-height:1.4;
  color:var(--text-2);
  text-decoration:none;
  border-radius:9px;
  white-space:nowrap;
  transition:color var(--ease),background-color var(--ease);
}
.nav-link:hover{color:var(--text);background:rgba(53,230,210,.09)}
.nav-link[aria-current="page"]{
  color:#04121F;
  background:var(--cyan);
  font-weight:700;
  box-shadow:0 6px 18px -8px rgba(53,230,210,.9);
}

.header-actions{
  display:flex;
  align-items:center;
  gap:10px;
  flex:0 0 auto;
}

/* 汉堡按钮 */
.nav-toggle{
  display:none;
  align-items:center;
  justify-content:center;
  width:44px;
  height:44px;
  padding:0;
  border:1px solid var(--line);
  border-radius:12px;
  background:rgba(18,34,74,.6);
  color:var(--cyan);
  cursor:pointer;
  transition:border-color var(--ease),background-color var(--ease);
}
.nav-toggle:hover{border-color:var(--cyan);background:rgba(53,230,210,.12)}
.nav-toggle-bars{display:block;width:18px;height:12px;position:relative}
.nav-toggle-bar{
  position:absolute;
  left:0;
  width:100%;
  height:2px;
  border-radius:2px;
  background:currentColor;
  transition:transform var(--ease),opacity var(--ease),top var(--ease);
}
.nav-toggle-bar:nth-child(1){top:0}
.nav-toggle-bar:nth-child(2){top:5px}
.nav-toggle-bar:nth-child(3){top:10px}
.site-header[data-open="true"] .nav-toggle-bar:nth-child(1){top:5px;transform:rotate(45deg)}
.site-header[data-open="true"] .nav-toggle-bar:nth-child(2){opacity:0}
.site-header[data-open="true"] .nav-toggle-bar:nth-child(3){top:5px;transform:rotate(-45deg)}

/* 第二栏：WELCOME 娱乐平台本地栏目板块 */
.header-sub{
  display:flex;
  align-items:center;
  gap:16px;
  padding:9px 0 10px;
  border-top:1px solid var(--line);
  min-width:0;
}
.sub-label{
  display:inline-flex;
  align-items:center;
  font-family:var(--font-latin);
  font-weight:600;
  font-size:12px;
  letter-spacing:.12em;
  color:var(--cyan-soft);
  white-space:nowrap;
  flex:0 0 auto;
}
.sub-label::before{
  content:"";
  width:6px;height:6px;
  margin-right:9px;
  border-radius:50%;
  background:var(--cyan);
  box-shadow:0 0 10px var(--cyan);
}
.sub-nav{
  display:flex;
  gap:6px;
  margin:0;
  padding:0;
  min-width:0;
  overflow-x:auto;
  scrollbar-width:none;
}
.sub-nav::-webkit-scrollbar{display:none}
.sub-item{flex:0 0 auto}
.sub-link{
  display:inline-block;
  padding:4px 12px;
  font-size:12.5px;
  line-height:1.5;
  letter-spacing:.05em;
  color:var(--text-2);
  text-decoration:none;
  border:1px solid var(--line);
  border-radius:999px;
  white-space:nowrap;
  transition:color var(--ease),background-color var(--ease),border-color var(--ease);
}
.sub-link:hover{
  color:#08111F;
  background:var(--gold);
  border-color:var(--gold-deep);
}
.sub-version{
  margin-left:auto;
  font-size:12px;
  letter-spacing:.1em;
  color:var(--text-3);
  white-space:nowrap;
  flex:0 0 auto;
}

/* 移动端遮罩 */
.nav-scrim{
  position:fixed;
  inset:0;
  z-index:310;
  background:rgba(3,7,17,.74);
  opacity:0;
  pointer-events:none;
  transition:opacity var(--ease);
}

/* ---------- 5. 容器与栅格 ---------- */
.wrap{
  width:100%;
  max-width:var(--frame-max);
  margin:0 auto;
  padding:0 var(--frame-x);
}

.grid{
  display:grid;
  gap:clamp(16px,2.4vw,28px);
  grid-template-columns:1fr;
}

main{display:block}

/* ---------- 6. 章节节奏 ---------- */
.section{padding:clamp(46px,7vw,96px) 0}
.section--tight{padding:clamp(30px,4vw,56px) 0}

.section-head{
  display:flex;
  flex-wrap:wrap;
  align-items:flex-end;
  justify-content:space-between;
  gap:14px 28px;
  margin-bottom:clamp(22px,3vw,42px);
}
.section-title{margin:8px 0 0;}
.section-note{
  font-size:13px;
  line-height:1.8;
  color:var(--text-3);
  max-width:26em;
  margin:0;
}

.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-latin);
  font-size:12px;
  font-weight:600;
  letter-spacing:.22em;
  text-transform:uppercase;
  color:var(--cyan-soft);
}
.eyebrow::before{
  content:"";
  width:26px;
  height:1px;
  background:linear-gradient(90deg,var(--cyan),rgba(53,230,210,0));
}

.vertical-note{
  writing-mode:vertical-rl;
  text-orientation:mixed;
  font-family:var(--font-head);
  font-size:12px;
  font-weight:500;
  letter-spacing:.3em;
  color:var(--text-3);
  user-select:none;
}

/* ---------- 7. 图文错位块 ---------- */
.offset-block{
  display:grid;
  grid-template-columns:1fr;
  gap:clamp(18px,2.6vw,34px);
  align-items:center;
}
.offset-text,.offset-visual{min-width:0}

/* ---------- 8. 卡片与数据 ---------- */
.card{
  position:relative;
  background:linear-gradient(160deg,rgba(18,34,74,.94),rgba(11,23,48,.86));
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:clamp(18px,2.2vw,28px);
  box-shadow:inset 0 1px 0 rgba(234,242,255,.05),0 18px 42px -32px rgba(0,0,0,.95);
  transition:transform var(--ease),border-color var(--ease),box-shadow var(--ease);
}
.card::after{
  content:"";
  position:absolute;
  inset:-1px;
  border-radius:inherit;
  pointer-events:none;
  opacity:0;
  background:radial-gradient(420px 180px at 82% -20%,rgba(53,230,210,.24),transparent 70%);
  transition:opacity var(--ease);
}
.card:hover{
  transform:translateY(-4px);
  border-color:rgba(53,230,210,.44);
  box-shadow:0 0 0 1px rgba(53,230,210,.14),0 28px 52px -30px rgba(53,230,210,.36);
}
.card:hover::after{opacity:.7}
.card-head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  margin-bottom:14px;
}
.card-title{margin:0;font-size:17px;font-weight:800;letter-spacing:.02em}
.card-kicker{
  font-family:var(--font-latin);
  font-size:11.5px;
  font-weight:600;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--text-3);
}

.stat-value{
  display:block;
  font-size:clamp(26px,3.2vw,40px);
  font-weight:500;
  line-height:1.1;
  color:var(--cyan);
  letter-spacing:-.01em;
}
.stat-label{
  display:block;
  margin-top:8px;
  font-size:12.5px;
  letter-spacing:.14em;
  color:var(--text-3);
}

/* ---------- 9. 时间轴 ---------- */
.timeline{
  position:relative;
  margin:0;
  padding:0 0 0 30px;
  border-left:1px solid var(--line);
}
.timeline-item{
  position:relative;
  padding-bottom:26px;
}
.timeline-item:last-child{padding-bottom:0}
.timeline-item::before{
  content:"";
  position:absolute;
  left:-35px;
  top:8px;
  width:9px;
  height:9px;
  border-radius:50%;
  background:var(--ink-0);
  border:1px solid var(--cyan);
  box-shadow:0 0 0 4px rgba(53,230,210,.1);
}
.timeline-meta{
  display:block;
  font-size:12px;
  letter-spacing:.08em;
  color:var(--text-3);
  margin-bottom:4px;
}

/* ---------- 10. 折叠问答 ---------- */
.accordion{border-top:1px solid var(--line)}
.accordion-item{border-bottom:1px solid var(--line)}
.accordion-trigger{
  width:100%;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding:20px 0;
  background:none;
  border:0;
  color:var(--text);
  font-family:var(--font-head);
  font-weight:700;
  font-size:16px;
  line-height:1.5;
  text-align:left;
  cursor:pointer;
  transition:color var(--ease);
}
.accordion-trigger::after{
  content:"+";
  flex:0 0 auto;
  font-family:var(--font-mono);
  font-size:20px;
  line-height:1;
  color:var(--cyan);
  transition:transform var(--ease),color var(--ease);
}
.accordion-trigger:hover{color:var(--cyan-soft)}
.accordion-trigger[aria-expanded="true"]::after{content:"–";color:var(--gold)}
.accordion-panel{padding:0 0 20px;font-size:14.5px;color:var(--text-2)}
.accordion-panel[hidden]{display:none}

/* ---------- 11. 按钮 ---------- */
.btn{
  --btn-bg:transparent;
  --btn-fg:var(--text);
  --btn-bd:var(--line);
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:9px;
  min-height:46px;
  padding:12px 24px;
  font-family:var(--font-head);
  font-weight:700;
  font-size:15px;
  letter-spacing:.04em;
  line-height:1.2;
  color:var(--btn-fg);
  background:var(--btn-bg);
  border:1px solid var(--btn-bd);
  border-radius:999px;
  text-decoration:none;
  cursor:pointer;
  transition:transform var(--ease),box-shadow var(--ease),background-color var(--ease),color var(--ease),border-color var(--ease);
}
.btn:hover{transform:translateY(-3px);color:var(--btn-fg)}
.btn:active{transform:translateY(-1px) scale(.97)}

.btn-gold{
  --btn-bg:linear-gradient(135deg,#F2B33D,#C98A1F);
  --btn-fg:#091120;
  --btn-bd:#C98A1F;
  box-shadow:0 8px 24px -12px rgba(242,179,61,.9);
}
.btn-gold:hover{
  --btn-bg:linear-gradient(135deg,#FFC65B,#D8961F);
  color:#091120;
  box-shadow:0 14px 32px -14px rgba(242,179,61,.95);
}

.btn-cyan{
  --btn-bg:rgba(53,230,210,.12);
  --btn-fg:var(--cyan-soft);
  --btn-bd:rgba(53,230,210,.48);
}
.btn-cyan:hover{--btn-bg:rgba(53,230,210,.22);color:#04121F}

.btn-ghost{
  --btn-bg:rgba(11,23,48,.62);
  --btn-fg:var(--text-2);
  --btn-bd:var(--line);
}
.btn-ghost:hover{--btn-fg:var(--text);--btn-bd:var(--cyan)}

.btn-sm{min-height:38px;padding:8px 18px;font-size:13.5px;letter-spacing:.03em}
.btn-block{width:100%}

/* ---------- 12. 面包屑 ---------- */
.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  margin:0 0 22px;
  padding:0;
  font-size:12.5px;
  line-height:1.6;
  color:var(--text-3);
}
.breadcrumb li{display:inline-flex;align-items:center;gap:8px}
.breadcrumb li + li::before{content:"/";color:var(--line)}
.breadcrumb a{color:var(--text-2);text-decoration:none;transition:color var(--ease)}
.breadcrumb a:hover{color:var(--cyan)}
.breadcrumb [aria-current="page"]{
  font-family:var(--font-mono);
  color:var(--cyan-soft);
}

/* ---------- 13. 媒体容器（供页面阶段放置图片 / 内联 SVG） ---------- */
.media{
  position:relative;
  display:block;
  width:100%;
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:var(--radius);
  background:
    linear-gradient(140deg,rgba(18,34,74,.95),rgba(5,11,26,.9)),
    var(--ink-1);
  isolation:isolate;
}
.media::after{
  content:"";
  position:absolute;
  inset:0;
  z-index:2;
  pointer-events:none;
  background:linear-gradient(180deg,rgba(5,11,26,0) 42%,rgba(5,11,26,.74) 100%);
}
.media > img,
.media > svg,
.media > video{
  display:block;
  width:100%;
  height:100%;
  object-fit:cover;
}
.media--16x9{aspect-ratio:16 / 9}
.media--4x3{aspect-ratio:4 / 3}
.media--1x1{aspect-ratio:1 / 1}
.media--tall{aspect-ratio:3 / 4}
.media-caption{
  display:block;
  margin-top:10px;
  font-size:12.5px;
  line-height:1.7;
  color:var(--text-3);
}

/* ---------- 14. 章节索引轨道 ---------- */
.chapter-rail{
  display:none;
  position:fixed;
  left:0;
  top:50%;
  transform:translateY(-50%);
  z-index:200;
  width:var(--rail);
  flex-direction:column;
  align-items:center;
  gap:20px;
  padding:22px 0;
  border-right:1px solid rgba(36,54,95,.72);
  border-top:1px solid rgba(36,54,95,.5);
  border-bottom:1px solid rgba(36,54,95,.5);
  background:linear-gradient(90deg,rgba(11,23,48,.94),rgba(11,23,48,.28));
}
.chapter-rail-link{
  writing-mode:vertical-rl;
  text-orientation:mixed;
  padding:6px 2px;
  font-family:var(--font-head);
  font-size:12px;
  font-weight:500;
  letter-spacing:.26em;
  color:var(--text-3);
  text-decoration:none;
  border-radius:6px;
  transition:color var(--ease);
}
.chapter-rail-link:hover{color:var(--text)}
.chapter-rail-link[aria-current="location"]{
  color:var(--cyan);
  text-shadow:0 0 14px rgba(53,230,210,.6);
}

/* ---------- 15. 返回顶部 ---------- */
.to-top{
  position:fixed;
  right:clamp(16px,3vw,36px);
  bottom:clamp(16px,3vw,36px);
  z-index:260;
  width:48px;
  height:48px;
  padding:0;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border:1px solid var(--line);
  border-radius:50%;
  background:rgba(11,23,48,.9);
  color:var(--cyan);
  cursor:pointer;
  opacity:0;
  transform:translateY(10px);
  pointer-events:none;
  transition:opacity var(--ease),transform var(--ease),border-color var(--ease),background-color var(--ease);
}
.to-top::before{
  content:"";
  width:9px;
  height:9px;
  margin-top:4px;
  border-left:2px solid currentColor;
  border-top:2px solid currentColor;
  transform:rotate(45deg);
}
.to-top[data-visible="true"]{
  opacity:1;
  transform:translateY(0);
  pointer-events:auto;
}
.to-top:hover{
  border-color:var(--cyan);
  background:rgba(53,230,210,.14);
}

/* ---------- 16. 页脚 ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(60px,9vw,130px);
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(11,23,48,.92),rgba(5,11,26,1));
}
.site-footer::before{
  content:"";
  position:absolute;
  left:0;right:0;top:-1px;
  height:1px;
  background:linear-gradient(90deg,transparent,rgba(53,230,210,.7),rgba(242,179,61,.5),transparent);
}
.footer-frame{
  width:100%;
  max-width:var(--frame-max);
  margin:0 auto;
  padding:clamp(38px,5.6vw,72px) var(--frame-x) 26px;
}
.footer-head{
  display:grid;
  grid-template-columns:1fr;
  gap:18px 32px;
  padding-bottom:26px;
  border-bottom:1px solid var(--line);
}
.footer-brand{min-width:0}
.footer-brand-name{
  display:block;
  font-family:var(--font-head);
  font-weight:900;
  font-size:clamp(23px,3vw,34px);
  line-height:1.2;
  letter-spacing:.05em;
  color:var(--text);
}
.footer-brand-line{
  display:block;
  margin-top:9px;
  font-size:12.5px;
  letter-spacing:.18em;
  color:var(--text-3);
}
.footer-contact{
  margin:0;
  font-size:14px;
  line-height:1.95;
  color:var(--text-2);
  max-width:52em;
}
.footer-grid{
  display:grid;
  grid-template-columns:1fr;
  gap:26px;
  padding:30px 0;
}
.footer-col{min-width:0}
.footer-col-title{
  margin:0 0 14px;
  font-family:var(--font-latin);
  font-size:12px;
  font-weight:600;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--cyan-soft);
}
.footer-list{display:grid;gap:10px;margin:0;padding:0}
.footer-link{
  display:inline-flex;
  align-items:center;
  gap:9px;
  font-size:14.5px;
  color:var(--text-2);
  text-decoration:none;
  transition:color var(--ease);
}
.footer-link::before{
  content:"";
  width:14px;
  height:1px;
  background:var(--line);
  transition:width var(--ease),background-color var(--ease);
}
.footer-link:hover{color:var(--cyan)}
.footer-link:hover::before{width:24px;background:var(--gold)}
.footer-legal{
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  gap:8px 28px;
  padding-top:20px;
  border-top:1px solid var(--line);
}
.footer-legal-line{
  margin:0;
  font-size:12.5px;
  line-height:1.8;
  color:var(--text-3);
  max-width:none;
}

/* ---------- 17. 显现动效 ---------- */
html.js-enabled [data-reveal]{
  opacity:0;
  transform:translateY(18px);
  transition:opacity .62s ease,transform .62s ease;
}
html.js-enabled [data-reveal].is-visible{
  opacity:1;
  transform:none;
}

/* ---------- 18. 平板 ---------- */
@media (min-width:721px){
  .footer-head{grid-template-columns:minmax(0,1fr) minmax(0,1.5fr);align-items:end}
  .footer-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:28px;padding:34px 0}
}

@media (min-width:761px){
  .grid{grid-template-columns:repeat(12,minmax(0,1fr))}
  .grid > *{grid-column:span 12}
  .grid > .col-3{grid-column:span 3}
  .grid > .col-4{grid-column:span 4}
  .grid > .col-5{grid-column:span 5}
  .grid > .col-6{grid-column:span 6}
  .grid > .col-7{grid-column:span 7}
  .grid > .col-8{grid-column:span 8}
  .grid > .col-9{grid-column:span 9}
  .grid > .col-10{grid-column:span 10}
  .grid > .col-12{grid-column:span 12}

  .offset-block{grid-template-columns:repeat(12,minmax(0,1fr))}
  .offset-block > .offset-text{grid-column:2 / span 5}
  .offset-block > .offset-visual{grid-column:7 / span 6}
  .offset-block.is-reversed > .offset-text{grid-column:7 / span 5}
  .offset-block.is-reversed > .offset-visual{grid-column:1 / span 6}
}

/* ---------- 19. 移动端导航抽屉 ---------- */
@media (max-width:1080px){
  .nav-toggle{display:inline-flex}

  .nav-scrim{
    opacity:0;
    pointer-events:none;
  }
  .site-header[data-open="true"] .nav-scrim{
    opacity:1;
    pointer-events:auto;
  }

  .primary-nav{
    position:fixed;
    top:0;
    right:0;
    bottom:0;
    z-index:315;
    display:block;
    width:min(340px,88vw);
    margin-left:0;
    padding:112px 22px 34px;
    overflow-y:auto;
    background:linear-gradient(180deg,var(--ink-1),var(--ink-0) 70%);
    border-left:1px solid var(--line);
    box-shadow:-30px 0 60px -40px rgba(0,0,0,.95);
    transform:translateX(103%);
    transition:transform .28s cubic-bezier(.22,.61,.36,1);
  }
  .site-header[data-open="true"] .primary-nav{transform:translateX(0)}

  .nav-list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
  }
  .nav-item{border-bottom:1px solid rgba(36,54,95,.6)}
  .nav-link{
    display:block;
    padding:15px 6px;
    font-size:17px;
    font-family:var(--font-head);
    font-weight:700;
    border-radius:0;
  }
  .nav-link[aria-current="page"]{
    background:transparent;
    color:var(--cyan);
    box-shadow:none;
  }
  .nav-link[aria-current="page"]::before{
    content:"";
    display:inline-block;
    width:7px;height:7px;
    margin-right:10px;
    border-radius:50%;
    background:var(--gold);
    vertical-align:middle;
  }
}

/* ---------- 20. 手机 ---------- */
@media (max-width:700px){
  :root{--header-h:64px}
  .brand-line{display:none}
  .header-cta{display:none}
  .header-sub{gap:10px;padding:8px 0 9px}
  .sub-label{font-size:11px;letter-spacing:.06em}
  .sub-label::before{width:5px;height:5px;margin-right:6px}
  .sub-version{display:none}
  .header-actions{gap:8px}
  .vertical-note{display:none}
  .footer-legal{flex-direction:column;justify-content:flex-start}
}

@media (max-width:420px){
  .sub-label{display:none}
}

/* ---------- 21. 宽屏章节轨道 ---------- */
@media (min-width:1600px){
  .chapter-rail{display:flex}
}

/* ---------- 22. 减少动态偏好 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;scroll-padding-top:96px}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .card:hover{transform:none}
  .btn:hover{transform:none}
  .to-top{transform:none}
  html.js-enabled [data-reveal]{opacity:1;transform:none}
  body::before{background:
    radial-gradient(920px 540px at 84% -8%, rgba(53,230,210,.12), transparent 66%),
    linear-gradient(180deg,#050B1A 0%,#071027 48%,#050B1A 100%);
  }
}