/* =========================================================
   Netflix Culture Handbook · 红黑电影感编辑风 设计系统
   暗色默认，浅色可选；localStorage key: hk-theme
   ========================================================= */
:root{
  /* 品牌色 */
  --red:#E50914;
  --red-2:#B20710;
  --red-glow:rgba(229,9,20,.55);
  --gold:#F5C518;
  --ink:#0B0B0F;
  --ink-2:#15151B;
  --ink-3:#1E1E26;
  --paper:#F5F5F7;
  --text:#ECECEF;
  --muted:#9A9AA6;
  --line:rgba(255,255,255,.10);
  --line-strong:rgba(255,255,255,.18);
  --card:rgba(255,255,255,.035);
  --card-2:rgba(255,255,255,.06);
  --good:#3FB98A;
  --bad:#E5564B;
  /* 尺度 */
  --maxw:1140px;
  --nav-h:64px;
  --radius:16px;
  --radius-sm:11px;
  --serif:'Georgia','Songti SC','STSong',serif;
  --sans:'Netflix Sans','Helvetica Neue',Arial,'PingFang SC','Microsoft YaHei',sans-serif;
  --shadow:0 18px 50px rgba(0,0,0,.45);
  --shadow-hover:0 26px 70px rgba(229,9,20,.22);
}
[data-theme="light"]{
  --ink:#F5F5F7;
  --ink-2:#FFFFFF;
  --ink-3:#FFFFFF;
  --paper:#FFFFFF;
  --text:#16161A;
  --muted:#5C5C66;
  --line:rgba(0,0,0,.10);
  --line-strong:rgba(0,0,0,.16);
  --card:rgba(0,0,0,.025);
  --card-2:rgba(0,0,0,.045);
  --shadow:0 18px 50px rgba(0,0,0,.12);
  --shadow-hover:0 26px 70px rgba(229,9,20,.18);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:var(--sans);
  background:var(--ink);
  color:var(--text);
  line-height:1.8;
  -webkit-font-smoothing:antialiased;
  transition:background .35s,color .35s;
  overflow-x:hidden;
}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
:focus-visible{outline:2px solid var(--red);outline-offset:3px;border-radius:6px}
.container{max-width:var(--maxw);margin:0 auto;padding:0 32px;width:100%}
img,svg{max-width:100%}

/* ===================== 顶栏 ===================== */
.topbar{
  position:fixed;top:0;left:0;right:0;height:var(--nav-h);z-index:100;
  display:flex;align-items:center;
  background:rgba(11,11,15,.72);
  backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
  border-bottom:1px solid var(--line);
  transition:background .35s,border-color .35s;
}
[data-theme="light"] .topbar{background:rgba(245,245,247,.8)}
.nav-inner{max-width:var(--maxw);margin:0 auto;width:100%;padding:0 32px;display:flex;align-items:center;justify-content:space-between;gap:16px}
.sg-back{display:flex;align-items:center;gap:7px;font-size:.86rem;font-weight:600;color:var(--muted);padding:8px 13px;border-radius:10px;border:1px solid var(--line);transition:all .2s}
.sg-back:hover{color:var(--text);border-color:var(--red);background:var(--card)}
.sg-back svg{width:15px;height:15px}
.brand{display:flex;align-items:center;gap:10px;font-weight:900;font-size:1.05rem;letter-spacing:.02em}
.brand .n{color:var(--red);font-weight:900}
.brand .mark{width:24px;height:24px;color:var(--red)}
.theme-btn{width:38px;height:38px;flex-shrink:0;display:flex;align-items:center;justify-content:center;border-radius:10px;color:var(--muted);border:1px solid var(--line);transition:all .2s}
.theme-btn:hover{color:var(--text);border-color:var(--red);background:var(--card)}
.theme-btn svg{width:18px;height:18px}

/* ===================== 首页 Hero ===================== */
.hero{
  position:relative;padding:calc(var(--nav-h) + 92px) 32px 72px;text-align:center;overflow:hidden;
  background:
    radial-gradient(900px 520px at 50% -8%,var(--red-glow),transparent 60%),
    linear-gradient(180deg,var(--ink) 0%,var(--ink-2) 100%);
}
.hero::after{content:"";position:absolute;inset:0;background:radial-gradient(600px 380px at 85% 110%,rgba(245,197,24,.08),transparent 60%);pointer-events:none}
.hero-inner{position:relative;z-index:2;max-width:860px;margin:0 auto}
.hero .kicker{display:inline-block;font-size:.74rem;letter-spacing:.32em;text-transform:uppercase;color:var(--gold);border:1px solid rgba(245,197,24,.4);padding:6px 16px;border-radius:999px;margin-bottom:26px}
.hero h1{font-size:clamp(2.3rem,6vw,4.1rem);font-weight:900;line-height:1.08;letter-spacing:-.02em;margin-bottom:20px}
.hero h1 .hl{color:var(--red)}
.hero .lead{font-size:clamp(1.02rem,2.2vw,1.28rem);color:var(--muted);font-weight:300;max-width:640px;margin:0 auto;line-height:1.7}
.hero .scroll-hint{margin-top:34px;font-size:.78rem;letter-spacing:.18em;text-transform:uppercase;color:var(--muted);display:inline-flex;flex-direction:column;align-items:center;gap:8px}
.hero .scroll-hint .dot{width:6px;height:6px;border-radius:50%;background:var(--red);animation:bob 1.6s ease-in-out infinite}
@keyframes bob{0%,100%{transform:translateY(0);opacity:.4}50%{transform:translateY(7px);opacity:1}}

/* ===================== 文化系统图 ===================== */
.diagram-wrap{padding:18px 0 8px}
.diagram-cap{text-align:center;color:var(--muted);font-size:.9rem;margin:8px auto 0;max-width:620px}
.diagram{width:100%;max-width:760px;margin:0 auto;display:block}
.diagram .node{cursor:pointer;transition:transform .25s}
.diagram .node .box{transition:fill .25s,stroke .25s}
.diagram .node:hover .box{fill:var(--red);stroke:var(--red)}
.diagram .node:hover text{fill:#fff}
.diagram .node .box{fill:var(--ink-2);stroke:var(--line-strong)}
.diagram .node text{fill:var(--text);font-family:var(--sans);font-weight:700;pointer-events:none}
.diagram .node .sub{fill:var(--muted);font-weight:500;font-size:11px}
.diagram .hub .box{fill:var(--ink-3);stroke:var(--gold)}
.diagram .hub:hover .box{fill:var(--gold);stroke:var(--gold)}
.diagram .hub:hover text{fill:#0B0B0F}
.diagram .ring{fill:none;stroke:var(--red);stroke-width:2;stroke-dasharray:5 7;opacity:.5}
.diagram .edge{stroke:var(--line-strong);stroke-width:1.6}
.diagram .flylabel{fill:var(--gold);font-family:var(--sans);font-weight:700;font-size:12px}

/* ===================== 书籍导航 ===================== */
.books{padding:64px 0 40px}
.section-head{text-align:center;margin-bottom:40px}
.section-head .eyebrow{font-size:.76rem;letter-spacing:.26em;text-transform:uppercase;color:var(--red);font-weight:800}
.section-head h2{font-size:clamp(1.7rem,4vw,2.5rem);font-weight:900;letter-spacing:-.01em;margin-top:10px}
.section-head p{color:var(--muted);margin-top:10px;font-size:1rem}

.pillars{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.chap-card{
  position:relative;display:flex;flex-direction:column;background:var(--card);
  border:1px solid var(--line);border-radius:var(--radius);padding:24px 22px 20px;overflow:hidden;
  transition:transform .22s,box-shadow .22s,border-color .22s;
}
.chap-card::before{content:"";position:absolute;top:0;left:0;right:0;height:3px;background:linear-gradient(90deg,var(--red),var(--gold));opacity:0;transition:opacity .25s}
.chap-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-hover);border-color:var(--red)}
.chap-card:hover::before{opacity:1}
.chap-card .num{font-family:var(--serif);font-size:.86rem;color:var(--red);font-weight:700;letter-spacing:.06em}
.chap-card h3{font-size:1.22rem;font-weight:800;margin:8px 0 8px;line-height:1.35}
.chap-card p{font-size:.9rem;color:var(--muted);line-height:1.65;flex:1}
.chap-card .more{margin-top:16px;display:flex;align-items:center;gap:6px;color:var(--red);font-weight:700;font-size:.88rem}
.chap-card .more svg{width:15px;height:15px;transition:transform .2s}
.chap-card:hover .more svg{transform:translateX(5px)}

/* 9 价值观子板块 */
.values-sub{margin-top:54px}
.values-sub .sub-title{display:flex;align-items:center;gap:12px;margin-bottom:22px}
.values-sub .sub-title .bar{width:4px;height:22px;background:var(--gold);border-radius:3px}
.values-sub .sub-title h3{font-size:1.3rem;font-weight:900}
.values-sub .sub-title span{color:var(--muted);font-size:.86rem}
.values-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.val-chip{
  display:flex;align-items:center;gap:13px;background:var(--card);border:1px solid var(--line);
  border-radius:var(--radius-sm);padding:14px 16px;transition:all .2s;
}
.val-chip:hover{transform:translateY(-4px);border-color:var(--gold);background:var(--card-2)}
.val-chip .ic{width:40px;height:40px;flex-shrink:0;border-radius:10px;background:var(--ink-3);display:flex;align-items:center;justify-content:center;color:var(--red);font-weight:900;font-size:1.05rem;font-family:var(--serif)}
.val-chip .vt{font-weight:800;font-size:1rem}
.val-chip .ve{color:var(--muted);font-size:.76rem}

/* ===================== 章节页 ===================== */
.chapter{padding-top:var(--nav-h)}
.ch-hero{position:relative;padding:74px 32px 56px;overflow:hidden;background:radial-gradient(800px 420px at 18% -10%,var(--red-glow),transparent 58%),linear-gradient(180deg,var(--ink-2),var(--ink))}
.ch-hero-inner{max-width:820px;margin:0 auto}
.ch-hero .crumb{font-size:.8rem;color:var(--muted);letter-spacing:.04em;margin-bottom:18px;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.ch-hero .crumb a:hover{color:var(--red)}
.ch-hero .ch-num{font-family:var(--serif);font-size:1rem;color:var(--gold);font-weight:700;letter-spacing:.1em}
.ch-hero h1{font-size:clamp(2rem,5vw,3.2rem);font-weight:900;line-height:1.1;letter-spacing:-.02em;margin:10px 0 16px}
.ch-hero .thesis{font-size:clamp(1.05rem,2.2vw,1.32rem);color:var(--text);font-weight:300;line-height:1.7;max-width:680px}
.ch-hero .tag-row{margin-top:22px;display:flex;gap:8px;flex-wrap:wrap}
.ch-tag{font-size:.74rem;font-weight:700;letter-spacing:.04em;color:var(--gold);border:1px solid rgba(245,197,24,.35);padding:4px 12px;border-radius:999px}

/* 章节主体布局：TOC + 正文 */
.ch-body{display:grid;grid-template-columns:230px 1fr;gap:48px;max-width:var(--maxw);margin:0 auto;padding:48px 32px 90px}
.rail{position:sticky;top:calc(var(--nav-h) + 22px);align-self:start;height:max-content}
.rail .rail-title{font-size:.74rem;letter-spacing:.22em;text-transform:uppercase;color:var(--muted);margin-bottom:14px}
.rail a{display:block;font-size:.9rem;color:var(--muted);padding:7px 12px;border-radius:8px;border-left:2px solid transparent;transition:all .2s;line-height:1.4}
.rail a:hover{color:var(--text);background:var(--card)}
.rail a.active{color:var(--red);border-left-color:var(--red);background:var(--card);font-weight:700}
.article{max-width:720px}

/* 叙事块 */
.block{margin-bottom:46px;scroll-margin-top:calc(var(--nav-h) + 20px)}
.block .bhead{display:flex;align-items:baseline;gap:14px;margin-bottom:14px}
.block .bnum{font-family:var(--serif);font-size:1.5rem;color:var(--red);font-weight:800;line-height:1}
.block h2{font-size:1.5rem;font-weight:800;letter-spacing:-.01em}
.block p{color:var(--text);margin-bottom:14px;font-size:1.04rem}
.block p.muted{color:var(--muted)}
.block .lead-p{font-size:1.12rem;color:var(--text)}

/* 拉引语 */
.pullquote{position:relative;border-left:4px solid var(--red);background:var(--card);padding:22px 26px;border-radius:0 var(--radius-sm) var(--radius-sm) 0;margin:22px 0;font-family:var(--serif);font-size:1.28rem;line-height:1.55;font-style:italic}
.pullquote .src{display:block;margin-top:12px;font-family:var(--sans);font-style:normal;font-size:.85rem;color:var(--muted);letter-spacing:.03em}

/* Do / Don't 双栏 */
.do-dont{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:20px 0}
.dd{border-radius:var(--radius-sm);padding:18px 18px 16px;border:1px solid var(--line)}
.dd.do{background:rgba(63,185,138,.07);border-color:rgba(63,185,138,.35)}
.dd.dont{background:rgba(229,86,75,.07);border-color:rgba(229,86,75,.35)}
.dd h4{font-size:.92rem;font-weight:800;margin-bottom:10px;display:flex;align-items:center;gap:8px}
.dd.do h4{color:var(--good)}
.dd.dont h4{color:var(--bad)}
.dd ul{list-style:none}
.dd li{font-size:.92rem;color:var(--text);padding:5px 0 5px 18px;position:relative;line-height:1.6}
.dd li::before{content:"";position:absolute;left:0;top:13px;width:6px;height:6px;border-radius:50%}
.dd.do li::before{background:var(--good)}
.dd.dont li::before{background:var(--bad)}

/* 金句卡 */
.quote-card{background:linear-gradient(135deg,var(--ink-3),var(--ink-2));border:1px solid var(--line);border-radius:var(--radius);padding:26px 28px;margin:22px 0}
.quote-card .q{font-family:var(--serif);font-size:1.3rem;line-height:1.55;font-style:italic}
.quote-card .q .hl{color:var(--gold)}
.quote-card .by{margin-top:12px;font-size:.84rem;color:var(--muted)}

/* 场景卡 */
.scenario{border:1px dashed var(--line-strong);border-radius:var(--radius);padding:22px 24px;margin:20px 0;background:var(--card)}
.scenario .lab{font-size:.74rem;letter-spacing:.18em;text-transform:uppercase;color:var(--red);font-weight:800;margin-bottom:10px}
.scenario .q{font-size:1.06rem;font-weight:600;margin-bottom:12px}
.scenario .opt{display:flex;flex-direction:column;gap:9px}
.scenario .opt button{text-align:left;background:var(--ink-3);border:1px solid var(--line);border-radius:10px;padding:12px 15px;font-size:.94rem;color:var(--text);transition:all .2s}
.scenario .opt button:hover{border-color:var(--red)}
.scenario .opt button.correct{border-color:var(--good);background:rgba(63,185,138,.12);color:var(--text)}
.scenario .opt button.wrong{border-color:var(--bad);background:rgba(229,86,75,.12)}
.scenario .feedback{margin-top:12px;font-size:.9rem;color:var(--muted);display:none}
.scenario .feedback.show{display:block}

/* 时间线 */
.timeline{position:relative;margin:22px 0;padding-left:26px}
.timeline::before{content:"";position:absolute;left:7px;top:6px;bottom:6px;width:2px;background:linear-gradient(var(--red),var(--gold))}
.tl{position:relative;margin-bottom:22px}
.tl::before{content:"";position:absolute;left:-23px;top:5px;width:12px;height:12px;border-radius:50%;background:var(--ink);border:2px solid var(--red)}
.tl .yr{font-family:var(--serif);font-weight:800;color:var(--gold);font-size:.95rem}
.tl .tx{font-size:1rem;color:var(--text);margin-top:2px}

/* 对比表 */
.tbl{width:100%;border-collapse:collapse;margin:20px 0;font-size:.95rem;border:1px solid var(--line);border-radius:var(--radius-sm);overflow:hidden}
.tbl th,.tbl td{padding:13px 16px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
.tbl th{background:var(--ink-3);font-weight:800;color:var(--text)}
.tbl tr:last-child td{border-bottom:none}
.tbl td:first-child{color:var(--muted);font-weight:600;width:34%}

/* 小结 / 反思 */
.recap{border-top:2px solid var(--line);margin-top:8px;padding-top:30px}
.recap h3{font-size:1.2rem;font-weight:800;margin-bottom:14px;color:var(--gold)}
.recap ul{list-style:none}
.recap li{position:relative;padding:7px 0 7px 24px;color:var(--text);font-size:1rem}
.recap li::before{content:"▸";position:absolute;left:0;color:var(--red);font-weight:800}
.reflect{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px 24px;margin-top:22px}
.reflect .lab{font-size:.74rem;letter-spacing:.18em;text-transform:uppercase;color:var(--red);font-weight:800;margin-bottom:12px}
.reflect .q{font-size:1.02rem;margin-bottom:10px;color:var(--text)}
.reflect .q span{color:var(--muted)}

/* 章节翻页 */
.ch-pager{display:flex;justify-content:space-between;gap:14px;max-width:var(--maxw);margin:0 auto;padding:0 32px 70px}
.ch-pager a{flex:1;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px;transition:all .2s;max-width:48%}
.ch-pager a:hover{border-color:var(--red);transform:translateY(-3px)}
.ch-pager .dir{font-size:.74rem;letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.ch-pager .tt{font-size:1.02rem;font-weight:800;margin-top:5px}
.ch-pager a.next{text-align:right}
.ch-pager a.next .tt{color:var(--red)}

/* ===================== 页脚 ===================== */
.footer{border-top:1px solid var(--line);padding:44px 32px;text-align:center;color:var(--muted);font-size:.88rem}
.footer .sig{font-family:var(--serif);color:var(--text);font-size:1.05rem;margin-bottom:8px}
.footer .fine{color:var(--muted);font-size:.8rem;margin-top:8px;letter-spacing:.02em}
.footer a{color:var(--red);font-weight:700}

/* ===================== 滚动渐显 ===================== */
.reveal{opacity:0;transform:translateY(18px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}.hero .scroll-hint .dot{animation:none}}

/* ===================== 响应式 ===================== */
@media (max-width:980px){
  .ch-body{grid-template-columns:1fr;gap:0}
  .rail{display:none}
  .pillars{grid-template-columns:repeat(2,1fr)}
  .values-grid{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:640px){
  .container{padding:0 20px}
  .nav-inner{padding:0 18px}
  .hero{padding:calc(var(--nav-h) + 60px) 20px 54px}
  .pillars,.values-grid{grid-template-columns:1fr}
  .do-dont{grid-template-columns:1fr}
  .ch-body{padding:36px 20px 70px}
  .ch-hero{padding:60px 20px 44px}
  .ch-pager{flex-direction:column;padding:0 20px 56px}
  .ch-pager a{max-width:100%}
  .ch-pager a.next{text-align:left}
}