/* =====================================================================
   一馆一脉 · 图书馆五层文化空间提案 H5
   v5.0.0  —  脉 / qi 主题重构 · 流体首屏 · 独占式全屏看图
   ===================================================================== */

:root{
  /* 取自真实效果图：宣纸 / 浅木 / 松绿墨 / 赭铜 / 艾草，并引入朱砂印为唯一强调色 */
  --paper:#F1EBDD;
  --paper-soft:#FAF6EE;
  --paper-warm:#EDE4D2;
  --ink:#14302A;          /* 松绿墨，主文字 */
  --ink-2:#21443A;
  --ink-soft:rgba(20,48,42,.66);
  --ink-faint:rgba(20,48,42,.42);
  --gold:#A87C4F;         /* 赭铜 */
  --gold-soft:#C9A87B;
  --sage:#7C9082;         /* 艾草 */
  --cinnabar:#B6442F;     /* 朱砂印 —— 全篇唯一的“一处大胆” */
  --cinnabar-soft:#C9603F;
  --line:rgba(20,48,42,.13);
  --line-strong:rgba(20,48,42,.22);
  --shadow:0 30px 80px -28px rgba(20,48,42,.34);
  --shadow-soft:0 18px 50px -24px rgba(20,48,42,.28);

  --wrap:min(1180px,calc(100vw - 48px));
  --header-h:66px;
  --radius:22px;
  --radius-lg:30px;
  --ease:cubic-bezier(.22,1,.36,1);
  --ease-soft:cubic-bezier(.4,0,.2,1);

  --font-display:"Songti SC","STSong","SimSun","Noto Serif SC",serif;
  --font-kai:"Kaiti SC","STKaiti","KaiTi","楷体",serif;
  --font-sans:-apple-system,BlinkMacSystemFont,system-ui,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth;background:var(--paper);-webkit-text-size-adjust:100%}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

body{
  margin:0;min-width:320px;overflow-x:hidden;
  color:var(--ink);background:var(--paper);
  font-family:var(--font-sans);
  font-size:16px;line-height:1.72;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
}
body.lock-scroll{overflow:hidden}

img{max-width:100%;display:block}
button{font-family:inherit}
:focus-visible{outline:2px solid var(--cinnabar);outline-offset:3px;border-radius:4px}

.skip-link{
  position:fixed;top:-60px;left:14px;z-index:5000;
  background:var(--ink);color:var(--paper-soft);padding:10px 16px;border-radius:10px;
  transition:top .2s var(--ease);text-decoration:none;font-size:14px
}
.skip-link:focus{top:14px}

.wrap{width:var(--wrap);margin-inline:auto}

/* ----------------------------------------------------------------- *
   流体首屏画布 + 全页气韵底
 * ----------------------------------------------------------------- */
#fluid-hero{
  position:absolute;inset:0;width:100%;height:100%;
  z-index:0;pointer-events:none;display:block
}
#fluid-ambient{
  position:fixed;inset:0;width:100%;height:100%;
  z-index:-3;pointer-events:none;opacity:.5;display:block
}
.paper-grain{
  position:fixed;inset:0;z-index:-2;pointer-events:none;opacity:.05;
  background-image:
    radial-gradient(rgba(20,48,42,.5) .5px,transparent .6px);
  background-size:3px 3px;mix-blend-mode:multiply
}

/* 顶部阅读进度 */
.progress{position:fixed;left:0;right:0;top:0;height:2px;z-index:1500;background:transparent}
.progress span{
  display:block;height:100%;transform:scaleX(0);transform-origin:0 50%;
  background:linear-gradient(90deg,var(--gold),var(--cinnabar));
  transition:transform .12s linear
}

/* ----------------------------------------------------------------- *
   头部导航
 * ----------------------------------------------------------------- */
.site-header{
  position:fixed;top:0;left:0;right:0;z-index:1000;height:var(--header-h);
  display:flex;align-items:center;justify-content:space-between;
  padding-inline:clamp(16px,4vw,40px);
  background:rgba(241,235,221,0);backdrop-filter:blur(0);
  transition:background .4s var(--ease),backdrop-filter .4s var(--ease),box-shadow .4s var(--ease)
}
.site-header.scrolled{
  background:rgba(244,239,228,.82);backdrop-filter:saturate(1.2) blur(14px);
  box-shadow:0 1px 0 var(--line)
}
.brand{display:flex;align-items:center;gap:11px;text-decoration:none;color:inherit}
.brand-seal{
  width:38px;height:38px;display:grid;place-items:center;flex:none;
  font-family:var(--font-kai);font-size:21px;color:var(--paper-soft);
  background:linear-gradient(150deg,var(--cinnabar),var(--cinnabar-soft));
  border-radius:9px;box-shadow:0 6px 18px -8px var(--cinnabar);
  letter-spacing:0
}
.brand-name b{display:block;font-family:var(--font-display);font-size:17px;letter-spacing:.16em;line-height:1.1}
.brand-name small{display:block;font-size:10.5px;color:var(--ink-faint);letter-spacing:.1em;margin-top:1px}

.menu-toggle{
  display:none;position:relative;width:42px;height:42px;border:1px solid var(--line-strong);
  background:rgba(255,255,255,.4);border-radius:11px;cursor:pointer
}
.menu-toggle span{
  position:absolute;left:11px;width:20px;height:1.6px;background:var(--ink);border-radius:2px;
  transition:.3s var(--ease)
}
.menu-toggle span:nth-child(1){top:15px}
.menu-toggle span:nth-child(2){top:20px}
.menu-toggle span:nth-child(3){top:25px}
.menu-toggle[aria-expanded="true"] span:nth-child(1){top:20px;transform:rotate(45deg)}
.menu-toggle[aria-expanded="true"] span:nth-child(2){opacity:0}
.menu-toggle[aria-expanded="true"] span:nth-child(3){top:20px;transform:rotate(-45deg)}
.menu-toggle em{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}

.site-nav{display:flex;align-items:center;gap:4px}
.site-nav a,.site-nav button{
  appearance:none;border:0;background:transparent;cursor:pointer;
  font-family:var(--font-sans);font-size:14px;color:var(--ink-soft);
  padding:8px 13px;border-radius:9px;text-decoration:none;
  transition:color .25s var(--ease),background .25s var(--ease);position:relative
}
.site-nav a::after{
  content:"";position:absolute;left:13px;right:13px;bottom:4px;height:1.5px;
  background:var(--cinnabar);transform:scaleX(0);transform-origin:0;transition:transform .3s var(--ease)
}
.site-nav a:hover,.site-nav button:hover{color:var(--ink)}
.site-nav a.active{color:var(--ink)}
.site-nav a.active::after{transform:scaleX(1)}
.site-nav button[data-open-gallery]{
  color:var(--paper-soft);background:var(--ink);margin-left:8px
}
.site-nav button[data-open-gallery]:hover{background:var(--ink-2)}

/* ----------------------------------------------------------------- *
   首屏 HERO  —— 流体为主角
 * ----------------------------------------------------------------- */
.hero{
  position:relative;min-height:100svh;display:flex;align-items:center;
  padding-top:calc(var(--header-h) + 40px);padding-bottom:84px;overflow:hidden
}
.hero-veil{
  position:absolute;inset:0;z-index:1;pointer-events:none;
  background:
    radial-gradient(120% 90% at 18% 40%,rgba(241,235,221,.34),rgba(241,235,221,0) 60%),
    linear-gradient(180deg,rgba(241,235,221,.1),rgba(241,235,221,.5) 88%)
}
.hero-layout{position:relative;z-index:2;display:grid;grid-template-columns:1fr;gap:30px;align-items:center}

.eyebrow{
  display:inline-flex;align-items:center;gap:9px;margin:0;
  font-size:12.5px;letter-spacing:.2em;color:var(--gold);font-weight:600
}
.eyebrow::before{content:"";width:22px;height:1.5px;background:var(--gold)}

.hero-title{
  margin:18px 0 0;font-family:var(--font-display);font-weight:600;
  line-height:.92;letter-spacing:.02em;color:var(--ink);
  font-size:clamp(76px,20vw,168px);
  display:flex;align-items:baseline;gap:.04em;flex-wrap:wrap;
  position:relative
}
.hero-title .seal{
  font-family:var(--font-kai);color:var(--cinnabar);
  -webkit-text-stroke:0;position:relative;
}
.hero-title .seal::after{
  content:"";position:absolute;right:-.14em;top:-.06em;width:.34em;height:.34em;
  border:2px solid var(--cinnabar);border-radius:6px;opacity:.5
}
.hero-lead{
  font-family:var(--font-kai);font-size:clamp(22px,4.6vw,38px);
  color:var(--ink-2);margin:20px 0 0;letter-spacing:.04em;line-height:1.4
}
.hero-lead b{color:var(--cinnabar);font-weight:inherit}
.hero-intro{
  margin:18px 0 0;max-width:36em;color:var(--ink-soft);
  font-size:clamp(15px,1.4vw,17px);line-height:1.85
}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:32px}
.hero-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:26px}
.hero-tags span{
  font-size:12.5px;color:var(--ink-soft);padding:6px 14px;border-radius:999px;
  background:rgba(255,255,255,.46);border:1px solid var(--line)
}

.button{
  appearance:none;cursor:pointer;border:0;text-decoration:none;
  display:inline-flex;align-items:center;gap:9px;
  font-family:var(--font-sans);font-size:14.5px;font-weight:600;letter-spacing:.02em;
  padding:14px 24px;border-radius:13px;transition:.28s var(--ease)
}
.button.primary{background:var(--ink);color:var(--paper-soft);box-shadow:var(--shadow-soft)}
.button.primary:hover{background:var(--ink-2);transform:translateY(-2px)}
.button.primary span{transition:transform .3s var(--ease)}
.button.primary:hover span{transform:translateY(2px)}
.button.secondary{background:rgba(255,255,255,.5);color:var(--ink);border:1px solid var(--line-strong)}
.button.secondary:hover{background:#fff;transform:translateY(-2px)}
.button.light{background:var(--paper-soft);color:var(--ink)}
.button.light:hover{transform:translateY(-2px)}
.button.outline{background:transparent;color:var(--paper-soft);border:1px solid rgba(255,255,255,.4)}
.button.outline:hover{background:rgba(255,255,255,.1)}

/* 首屏底部走字 */
.hero-ticker{
  position:absolute;left:0;right:0;bottom:22px;z-index:2;overflow:hidden;
  -webkit-mask-image:linear-gradient(90deg,transparent,#000 12%,#000 88%,transparent);
          mask-image:linear-gradient(90deg,transparent,#000 12%,#000 88%,transparent)
}
.hero-ticker div{
  display:inline-flex;align-items:center;gap:18px;white-space:nowrap;
  font-family:var(--font-kai);font-size:14px;color:var(--ink-faint);letter-spacing:.1em;
  animation:ticker 26s linear infinite
}
.hero-ticker b{color:var(--cinnabar);opacity:.55}
@keyframes ticker{to{transform:translateX(-50%)}}

.hero-scroll-hint{
  position:absolute;left:50%;bottom:54px;z-index:2;transform:translateX(-50%);
  display:flex;flex-direction:column;align-items:center;gap:7px;
  font-size:10.5px;letter-spacing:.22em;color:var(--ink-faint)
}
.hero-scroll-hint i{
  width:1px;height:34px;background:linear-gradient(var(--gold),transparent);
  animation:scrollPulse 1.9s var(--ease) infinite
}
@keyframes scrollPulse{0%{transform:scaleY(.3);opacity:.4}50%{transform:scaleY(1);opacity:1}100%{transform:scaleY(.3);opacity:.4}}

/* ----------------------------------------------------------------- *
   通用区块
 * ----------------------------------------------------------------- */
.section{position:relative;padding:clamp(78px,9vw,132px) 0}
.section-index{
  display:flex;align-items:center;gap:14px;margin-bottom:30px;
  font-size:12px;letter-spacing:.2em;color:var(--ink-faint)
}
.section-index b{
  font-family:var(--font-display);font-size:15px;color:var(--cinnabar);
  border:1px solid var(--line-strong);border-radius:8px;padding:3px 10px;letter-spacing:.05em
}
.section-title h2{
  font-family:var(--font-display);font-weight:600;margin:10px 0 0;
  font-size:clamp(28px,4.4vw,46px);line-height:1.24;letter-spacing:.01em
}
.section-title h2 i{font-style:normal;color:var(--ink-soft)}
.heading-row{
  display:flex;justify-content:space-between;align-items:flex-end;gap:24px;
  margin-bottom:42px;flex-wrap:wrap
}
.heading-row>p{margin:0;max-width:30em;color:var(--ink-soft);font-size:15px;
  font-family:var(--font-kai);letter-spacing:.05em}

.text-button{
  appearance:none;border:0;background:transparent;cursor:pointer;flex:none;
  font-family:var(--font-sans);font-size:14px;font-weight:600;color:var(--ink);
  display:inline-flex;align-items:center;gap:6px;padding:4px 0;border-bottom:1.5px solid var(--cinnabar);
  transition:gap .25s var(--ease)
}
.text-button:hover{gap:11px}

/* 01 命题 */
.concept{background:linear-gradient(180deg,transparent,rgba(237,228,210,.5))}
.concept-grid{display:grid;grid-template-columns:1fr;gap:24px;margin-bottom:54px}
.concept-copy p{margin:0;color:var(--ink-soft);font-size:16px;line-height:1.95}
.concept-values{display:flex;flex-wrap:wrap;gap:9px;margin-top:24px}
.concept-values span{
  font-family:var(--font-kai);font-size:15px;color:var(--ink);
  padding:8px 16px;border-radius:11px;background:rgba(255,255,255,.55);
  border:1px solid var(--line);letter-spacing:.08em
}
.value-cards{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}
.value-cards article{
  background:rgba(255,255,255,.55);border:1px solid var(--line);
  border-radius:var(--radius);padding:26px 24px;transition:.35s var(--ease)
}
.value-cards article:hover{transform:translateY(-4px);box-shadow:var(--shadow-soft);background:#fff}
.value-cards b{
  font-family:var(--font-display);font-size:14px;color:var(--cinnabar);letter-spacing:.06em
}
.value-cards h3{font-family:var(--font-display);font-size:20px;margin:12px 0 8px;font-weight:600}
.value-cards p{margin:0;color:var(--ink-soft);font-size:14px;line-height:1.7}

/* 主张句 */
.statement{padding:clamp(70px,10vw,140px) 0;background:var(--ink);color:var(--paper-soft);position:relative;overflow:hidden}
.statement::before{
  content:"脉";position:absolute;right:-2vw;top:50%;transform:translateY(-50%);
  font-family:var(--font-kai);font-size:46vw;color:rgba(255,255,255,.03);line-height:1;pointer-events:none
}
.statement-inner{position:relative;text-align:center}
.statement-inner small{font-size:12px;letter-spacing:.3em;color:var(--gold-soft)}
.statement-inner p{
  font-family:var(--font-display);font-size:clamp(26px,5.2vw,52px);line-height:1.4;margin:18px 0 0;font-weight:600
}
.statement-inner p i{font-style:normal;color:var(--gold-soft)}

/* 02 动线 */
.plan-flow{
  display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:38px;
  font-family:var(--font-kai);font-size:clamp(15px,2.2vw,20px);color:var(--ink);letter-spacing:.06em
}
.plan-flow b{color:var(--cinnabar);font-weight:400}
.plan-flow .stage{display:inline-flex;flex-direction:column;align-items:center}
.plan-flow .stage em{font-style:normal;font-size:11px;color:var(--ink-faint);letter-spacing:.16em;font-family:var(--font-sans)}
.plan-card{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);
  padding:18px;box-shadow:var(--shadow-soft);overflow:hidden
}
.plan-image{
  border-radius:18px;overflow:hidden;background:var(--paper-warm);
  position:relative;cursor:zoom-in
}
.plan-image img{width:100%;height:auto;display:block;transition:transform .8s var(--ease)}
.plan-image:hover img{transform:scale(1.02)}
.plan-image .open-tag{
  position:absolute;right:12px;bottom:12px;display:inline-flex;align-items:center;gap:6px;
  font-size:12px;color:var(--paper-soft);background:rgba(20,48,42,.7);
  padding:7px 13px;border-radius:999px;backdrop-filter:blur(6px);pointer-events:none
}
.plan-links{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;margin-top:16px}
.plan-links a{
  text-decoration:none;color:inherit;border:1px solid var(--line);border-radius:15px;
  padding:16px 18px;display:flex;align-items:baseline;gap:10px;transition:.3s var(--ease);background:var(--paper-soft)
}
.plan-links a:hover{border-color:var(--cinnabar);transform:translateY(-3px);box-shadow:var(--shadow-soft)}
.plan-links b{font-family:var(--font-display);font-size:26px;color:var(--cinnabar);flex:none}
.plan-links span{font-family:var(--font-display);font-size:16px;font-weight:600}
.plan-links small{display:block;color:var(--ink-faint);font-size:12px;margin-top:2px}
.plan-links a>div{display:flex;flex-direction:column}

/* 03 点位深化 */
.chapter-card{
  display:grid;grid-template-columns:1fr;gap:0;
  border:1px solid var(--line);border-radius:var(--radius-lg);overflow:hidden;
  background:#fff;box-shadow:var(--shadow-soft);margin-bottom:0
}
.chapter-media{position:relative;overflow:hidden;cursor:zoom-in;background:var(--paper-warm);min-height:0}
.chapter-media img{width:100%;height:100%;object-fit:cover;aspect-ratio:16/10;transition:transform .85s var(--ease)}
.chapter-media:hover img{transform:scale(1.04)}
.chapter-media .zoom{
  position:absolute;right:14px;top:14px;width:42px;height:42px;border-radius:12px;border:0;
  background:rgba(20,48,42,.62);color:var(--paper-soft);font-size:17px;cursor:pointer;
  backdrop-filter:blur(6px);transition:.25s var(--ease)
}
.chapter-media:hover .zoom{background:var(--cinnabar)}
.chapter-copy{padding:32px 30px}
.chapter-tag{
  display:inline-flex;align-items:center;gap:8px;font-family:var(--font-kai);
  font-size:13px;color:var(--cinnabar);letter-spacing:.1em
}
.chapter-tag b{font-family:var(--font-display);font-size:13px;border:1px solid var(--line-strong);
  border-radius:6px;padding:1px 7px;color:var(--ink-soft)}
.chapter-location{margin:14px 0 0;font-size:12.5px;color:var(--ink-faint);letter-spacing:.06em}
.chapter-copy h3{
  font-family:var(--font-display);font-size:clamp(24px,3vw,32px);font-weight:600;
  margin:8px 0 0;line-height:1.25
}
.chapter-copy h3 i{font-style:normal;color:var(--ink-soft)}
.chapter-copy>p{margin:14px 0 0;color:var(--ink-soft);font-size:15px;line-height:1.85}
.chapter-copy dl{margin:22px 0 0;display:grid;gap:11px}
.chapter-copy dl>div{display:flex;gap:14px;border-top:1px solid var(--line);padding-top:11px}
.chapter-copy dt{flex:none;width:48px;font-size:12.5px;color:var(--ink-faint);letter-spacing:.08em}
.chapter-copy dd{margin:0;font-size:13.5px;color:var(--ink)}
.chapter-stack{display:grid;gap:18px}

/* 04 保留更新 */
.strategy{background:linear-gradient(180deg,rgba(237,228,210,.5),transparent)}
.strategy-grid{display:grid;grid-template-columns:1fr;gap:34px;align-items:center}
.strategy-copy h2{font-family:var(--font-display);font-weight:600;margin:10px 0 0;
  font-size:clamp(26px,4vw,42px);line-height:1.26}
.strategy-copy h2 i{font-style:normal;color:var(--ink-soft)}
.strategy-copy>p{margin:18px 0 0;color:var(--ink-soft);font-size:15.5px;line-height:1.9}
.strategy-list{margin-top:28px;display:grid;gap:14px}
.strategy-list>div{display:flex;gap:16px;align-items:baseline}
.strategy-list b{
  font-family:var(--font-kai);font-size:16px;color:var(--cinnabar);flex:none;width:42px
}
.strategy-list span{color:var(--ink-soft);font-size:14.5px}
.strategy-visual{margin:0;border-radius:var(--radius-lg);overflow:hidden;box-shadow:var(--shadow);
  background:#fff;border:1px solid var(--line);cursor:zoom-in;position:relative}
.strategy-visual img{width:100%;height:auto;display:block}
.strategy-visual figcaption{padding:18px 22px;border-top:1px solid var(--line)}
.strategy-visual figcaption b{display:block;font-size:14px;font-weight:600}
.strategy-visual figcaption span{display:block;font-size:12px;color:var(--ink-faint);margin-top:6px}

/* 05 视觉语言 */
.language-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}
.language-grid article{
  background:rgba(255,255,255,.5);border:1px solid var(--line);border-radius:var(--radius);
  padding:24px 22px;transition:.35s var(--ease)
}
.language-grid article:hover{background:#fff;transform:translateY(-4px);box-shadow:var(--shadow-soft)}
.language-grid article>span{
  display:grid;place-items:center;width:44px;height:44px;border-radius:12px;
  font-family:var(--font-kai);font-size:22px;color:var(--paper-soft);
  background:linear-gradient(150deg,var(--ink),var(--ink-2))
}
.language-grid h3{font-family:var(--font-display);font-size:18px;margin:16px 0 7px;font-weight:600}
.language-grid p{margin:0;color:var(--ink-soft);font-size:13.5px;line-height:1.7}

/* 收束 */
.finale{position:relative;overflow:hidden;background:var(--ink);color:var(--paper-soft);
  padding:clamp(90px,12vw,160px) 0;text-align:center}
.finale canvas{position:absolute;inset:0;width:100%;height:100%;opacity:.5;pointer-events:none}
.finale-inner{position:relative;z-index:2;max-width:760px;margin-inline:auto}
.finale .eyebrow{color:var(--gold-soft)}
.finale .eyebrow::before{background:var(--gold-soft)}
.finale h2{font-family:var(--font-display);font-weight:600;margin:18px 0 0;
  font-size:clamp(28px,5vw,52px);line-height:1.3}
.finale h2 i{font-style:normal;color:var(--gold-soft)}
.finale>.finale-inner>p{margin:22px auto 0;max-width:30em;color:rgba(250,246,238,.74);
  font-size:16px;line-height:1.9;font-family:var(--font-kai);letter-spacing:.04em}
.finale-quote{
  font-family:var(--font-display);font-size:clamp(20px,3.4vw,30px);
  margin:36px 0 0;line-height:1.5;color:var(--paper-soft)
}
.finale-quote b{color:var(--gold-soft);font-weight:inherit}
.final-actions{display:flex;justify-content:center;flex-wrap:wrap;gap:13px;margin-top:40px}

footer.site-foot{padding:30px 0;text-align:center;font-size:12px;color:var(--ink-faint);background:var(--paper)}
footer.site-foot b{color:var(--ink-soft);font-weight:600}

/* ----------------------------------------------------------------- *
   独占式全屏看图  —— 重写交互的核心
 * ----------------------------------------------------------------- */
.lightbox{
  position:fixed;inset:0;z-index:4000;display:none;
  background:rgba(8,18,15,.97);
  -webkit-user-select:none;user-select:none;touch-action:none
}
.lightbox.open{display:block}
.lightbox-stage{
  position:absolute;inset:0;overflow:hidden;
  display:flex;align-items:center;justify-content:center;
  cursor:grab
}
.lightbox-stage.is-zoomed{cursor:grab}
.lightbox-stage.dragging{cursor:grabbing}
.lightbox-stage img{
  max-width:100%;max-height:100%;width:auto;height:auto;object-fit:contain;
  will-change:transform;transform-origin:center center;
  transition:transform .26s var(--ease);
  -webkit-user-drag:none
}
.lightbox-stage.no-anim img{transition:none}

/* 浮层 chrome —— 全部悬浮在图上，不占图的空间 */
.lb-top{
  position:absolute;top:0;left:0;right:0;z-index:3;
  display:flex;align-items:center;justify-content:space-between;gap:12px;
  padding:14px clamp(14px,3vw,26px);
  background:linear-gradient(180deg,rgba(8,18,15,.65),transparent);
  transition:opacity .3s var(--ease)
}
.lb-title{display:flex;align-items:center;gap:9px;color:var(--paper-soft);min-width:0}
.lb-title span{
  width:30px;height:30px;flex:none;display:grid;place-items:center;border-radius:8px;
  font-family:var(--font-kai);font-size:16px;color:var(--paper-soft);
  background:linear-gradient(150deg,var(--cinnabar),var(--cinnabar-soft))
}
.lb-title b{font-family:var(--font-display);font-size:14px;letter-spacing:.08em;white-space:nowrap;
  overflow:hidden;text-overflow:ellipsis}
.lb-count{font-size:12px;letter-spacing:.14em;color:rgba(250,246,238,.6);flex:none}
.lb-close{
  width:42px;height:42px;flex:none;border:0;border-radius:12px;cursor:pointer;
  background:rgba(250,246,238,.12);color:var(--paper-soft);font-size:22px;line-height:1;
  transition:.25s var(--ease)
}
.lb-close:hover{background:var(--cinnabar)}

.lb-caption{
  position:absolute;left:0;right:0;bottom:96px;z-index:3;text-align:center;
  padding:0 20px;color:rgba(250,246,238,.82);font-size:13.5px;font-family:var(--font-kai);
  letter-spacing:.05em;pointer-events:none;
  text-shadow:0 1px 12px rgba(0,0,0,.6);transition:opacity .3s var(--ease)
}

.lb-nav{
  position:absolute;top:50%;transform:translateY(-50%);z-index:3;
  width:50px;height:50px;border:0;border-radius:50%;cursor:pointer;
  background:rgba(250,246,238,.12);color:var(--paper-soft);font-size:20px;
  backdrop-filter:blur(6px);transition:.25s var(--ease)
}
.lb-nav:hover{background:rgba(250,246,238,.24)}
.lb-nav.prev{left:clamp(10px,2vw,28px)}
.lb-nav.next{right:clamp(10px,2vw,28px)}
.lb-nav[hidden]{display:none}

.lb-thumbs{
  position:absolute;left:0;right:0;bottom:0;z-index:3;
  display:flex;gap:8px;padding:14px clamp(14px,3vw,26px);justify-content:center;
  overflow-x:auto;scrollbar-width:none;
  background:linear-gradient(0deg,rgba(8,18,15,.72),transparent);
  transition:opacity .3s var(--ease),transform .3s var(--ease)
}
.lb-thumbs::-webkit-scrollbar{display:none}
.lb-thumbs button{
  flex:none;width:64px;height:42px;border-radius:8px;overflow:hidden;cursor:pointer;
  border:1.5px solid transparent;background:transparent;opacity:.5;transition:.22s var(--ease);padding:0
}
.lb-thumbs button img{width:100%;height:100%;object-fit:cover}
.lb-thumbs button.active{opacity:1;border-color:var(--gold-soft);transform:translateY(-3px)}

/* 缩放/手势提示 */
.lb-hint{
  position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);z-index:2;
  display:flex;align-items:center;gap:8px;
  padding:9px 16px;border-radius:999px;pointer-events:none;
  background:rgba(8,18,15,.55);backdrop-filter:blur(6px);
  color:rgba(250,246,238,.9);font-size:12.5px;letter-spacing:.05em;
  opacity:0;transition:opacity .5s var(--ease)
}
.lb-hint.show{opacity:1}

/* 沉浸态：双击/缩放后自动淡出 chrome，露出整图 */
.lightbox.immersive .lb-top,
.lightbox.immersive .lb-caption,
.lightbox.immersive .lb-thumbs,
.lightbox.immersive .lb-nav{opacity:0;pointer-events:none}

/* 缩放刻度 */
.lb-scale{
  position:absolute;left:50%;bottom:96px;transform:translateX(-50%);z-index:3;
  font-size:11px;letter-spacing:.1em;color:rgba(250,246,238,.55);
  padding:5px 12px;border-radius:999px;background:rgba(8,18,15,.4);
  opacity:0;transition:opacity .3s var(--ease);pointer-events:none
}
.lb-scale.show{opacity:1}

/* ----------------------------------------------------------------- *
   reveal 入场
 * ----------------------------------------------------------------- */
.js .reveal{opacity:0;transform:translateY(22px);transition:opacity .8s var(--ease),transform .8s var(--ease)}
.js .reveal.is-visible{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  .js .reveal{opacity:1;transform:none;transition:none}
  .hero-ticker div,.hero-scroll-hint i{animation:none}
}

/* ----------------------------------------------------------------- *
   响应式：桌面增强
 * ----------------------------------------------------------------- */
@media (min-width:720px){
  .value-cards{grid-template-columns:repeat(4,1fr)}
  .language-grid{grid-template-columns:repeat(3,1fr)}
  .plan-links{grid-template-columns:repeat(4,1fr)}
  .chapter-card{grid-template-columns:1.15fr .85fr}
  .chapter-card.reverse .chapter-media{order:2}
  .chapter-media img{aspect-ratio:auto;height:100%;min-height:340px}
}
@media (min-width:920px){
  :root{--header-h:72px}
  .menu-toggle{display:none}
  .hero-layout{grid-template-columns:1.05fr .95fr;gap:48px}
  .concept-grid{grid-template-columns:.9fr 1.1fr;gap:48px}
  .strategy-grid{grid-template-columns:.92fr 1.08fr}
  .hero-title{font-size:clamp(120px,12vw,184px)}
}

/* ----------------------------------------------------------------- *
   响应式：移动端首屏重设计
 * ----------------------------------------------------------------- */
@media (max-width:919px){
  .menu-toggle{display:block}
  .site-nav{
    position:fixed;inset:var(--header-h) 0 auto;z-index:999;
    flex-direction:column;align-items:stretch;gap:2px;
    background:rgba(244,239,228,.97);backdrop-filter:blur(16px);
    padding:14px clamp(16px,4vw,40px) 24px;border-bottom:1px solid var(--line);
    transform:translateY(-120%);transition:transform .42s var(--ease);
    box-shadow:var(--shadow-soft)
  }
  .site-nav.open{transform:translateY(0)}
  .site-nav a,.site-nav button{font-size:16px;padding:13px 6px;text-align:left}
  .site-nav a::after{display:none}
  .site-nav button[data-open-gallery]{margin:8px 0 0;justify-content:center;padding:14px;border-radius:12px}

  .hero{min-height:100svh;padding-top:calc(var(--header-h) + 10px);padding-bottom:96px}
  .hero-layout{gap:6px;text-align:left}
  .hero-title{font-size:clamp(82px,26vw,140px);letter-spacing:0}
  .hero-lead{font-size:clamp(20px,6vw,28px)}
  .hero-intro{font-size:15px;line-height:1.8}
  .hero-actions{margin-top:26px}
  .hero-actions .button{flex:1 1 auto;justify-content:center}
  .hero-media-mobile{display:none}
  .hero-scroll-hint{bottom:64px}

  .chapter-copy{padding:26px 22px}
  .lb-nav{width:44px;height:44px}
  .lb-thumbs button{width:54px;height:36px}
  .lb-caption{bottom:88px;font-size:13px}
}

@media (max-width:420px){
  :root{--wrap:calc(100vw - 32px)}
  .hero-title{font-size:clamp(72px,24vw,108px)}
  .value-cards{grid-template-columns:1fr}
  .language-grid{grid-template-columns:1fr 1fr}
}