/* ============================================================
   SAT 新生手冊 2026 — stylesheet
   Visual system modeled on the Design Handbook reference:
   flat, monochrome, white surfaces, hairline rules, all-sans,
   numbered headings, generous vertical rhythm.
   Mobile-first. Breakpoints: 700px (tablet), 1040px (desktop)
   ============================================================ */
@font-face{
  font-family:"GenSen Rounded 2 TW";
  src:url("GenSenRounded2TW-R.woff2") format("woff2"),
      url("GenSenRounded2TW-R.otf") format("opentype");
  font-weight:400 900;
  font-style:normal;
  font-display:swap;
}
:root{
  --bg:#FFFFFF;
  --surface:#FFFFFF;
  --alt:#FFFFFF;            /* no colored bands — reference is all white */
  --ink:#0F0F0F;
  --ink-soft:#36352F;
  --muted:#8B897F;
  --line:#E7E5DE;           /* hairline */
  --line-strong:#CFCCC2;
  --accent:#0F0F0F;         /* monochrome — black for buttons/active */
  --accent-ink:#0F0F0F;
  --accent-soft:#EAEAEA90;  /* neutral grey wash (notes / active TOC) */
  --mark:#ECEAE1;
  --pill:#EAEAEA66;         /* header / cta pill fill — fixed shade */
  --pill-hover:#EAEAEA;     /* same hue, solid on hover */
  --bar:#0F0F0F;            /* thin top accent line — monochrome black */
  --maxw:1180px;
  --read:720px;             /* reading column width */
  /* Latin uses a crisp grotesque (Inter); CJK falls through to GenSen Rounded */
  --sans:"Inter","Helvetica Neue",Arial,"GenSen Rounded 2 TW","Noto Sans TC",sans-serif;
  --serif:var(--sans);       /* headings share the sans, like the reference */
}

/* ---------- Dark mode (monochrome — no colour) ---------- */
:root[data-theme="dark"]{
  --bg:#0E0E0F;
  --surface:#0E0E0F;
  --alt:#161617;
  --ink:#F2F1EC;
  --ink-soft:#CBC9C2;
  --muted:#8C8A83;
  --line:#2A2A2A;
  --line-strong:#3C3C3A;
  --accent:#F2F1EC;
  --accent-ink:#F2F1EC;
  --accent-soft:#FFFFFF14;
  --mark:#FFFFFF33;
  --pill:#FFFFFF14;
  --pill-hover:#FFFFFF29;
  --bar:#F2F1EC;
}
:root[data-theme="dark"] .site-header{background:rgba(14,14,15,.8)}
/* theme-toggle icon + brand logo swap */
.theme-toggle .icon-sun{display:none}
.brand-logo.brand-logo-dark{display:none}
:root[data-theme="dark"] .theme-toggle .icon-moon{display:none}
:root[data-theme="dark"] .theme-toggle .icon-sun{display:block}
:root[data-theme="dark"] .brand-logo-light{display:none}
:root[data-theme="dark"] .brand-logo-dark{display:block}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;background:var(--bg);color:var(--ink);
  font-family:var(--sans);font-size:16px;line-height:1.72;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
body::before{content:"";position:fixed;top:0;left:0;right:0;height:4px;background:var(--bar);z-index:110}
.content a:not(.pn),.prose a{color:var(--ink);text-decoration:underline;
  text-underline-offset:3px;text-decoration-thickness:1px;
  text-decoration-color:var(--line-strong);word-break:break-word;transition:.15s}
.content a:hover{text-decoration-color:var(--ink)}

/* ---------- Header ---------- */
.site-header{
  position:sticky;top:0;z-index:50;
  display:flex;align-items:center;justify-content:space-between;
  gap:16px;padding:18px 24px;
  background:rgba(255,255,255,.78);backdrop-filter:saturate(180%) blur(12px);
}
.brand{display:flex;align-items:center;gap:11px;min-width:0}
.brand-logo{height:clamp(30px,5vw,42px);width:auto;display:block}
.brand-mark{
  font-weight:700;letter-spacing:.06em;
  background:var(--ink);color:#fff;border-radius:4px;
  padding:6px 9px;font-size:14px;line-height:1;flex:none;
}
.brand-text{display:flex;flex-direction:column;line-height:1.18;min-width:0}
.brand-text strong{font-weight:600;font-size:15.5px;letter-spacing:.01em}
.brand-text em{font-style:normal;color:var(--muted);font-size:11.5px;letter-spacing:.03em}
.header-actions{display:flex;gap:8px;flex:none}
.hbtn{
  display:inline-flex;align-items:center;gap:8px;cursor:pointer;
  font-family:var(--sans);font-size:14.5px;font-weight:500;color:var(--ink);
  background:var(--pill);border:0;border-radius:999px;padding:10px 18px;transition:.15s;
}
.hbtn:hover{background:var(--pill-hover)}
.hbtn svg{color:var(--ink)}
.hbtn-icon{width:42px;height:42px;padding:0;justify-content:center}

/* ---------- Home: hero ---------- */
.home{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.hero{min-height:calc(100vh - 96px);display:flex;flex-direction:column;
  align-items:center;justify-content:center;text-align:center;padding:48px 0}
.hero-title{
  font-weight:700;letter-spacing:-.03em;
  font-size:clamp(40px,8.5vw,92px);line-height:1.0;margin:0;max-width:14ch;
}
.hero-sub{margin:22px 0 0;color:var(--muted);font-size:clamp(15px,2.2vw,19px);font-weight:500}
.hero .btn{margin-top:34px}
.hero-pdf{margin-top:16px;color:var(--muted);font-size:14px;text-decoration:underline;
  text-underline-offset:3px;text-decoration-color:var(--line-strong);transition:.15s}
.hero-pdf:hover{color:var(--ink);text-decoration-color:var(--ink)}
.btn{display:inline-flex;align-items:center;gap:9px;cursor:pointer;font-family:var(--sans);
  font-weight:600;font-size:16px;border-radius:999px;padding:14px 26px;transition:.18s;border:0}
.btn .arr{font-size:1.05em;line-height:1}
.btn-pill{background:var(--pill);color:var(--ink)}
.btn-pill:hover{background:var(--pill-hover);transform:translateY(-1px)}
.btn-solid{background:var(--ink);color:#fff}
.btn-solid:hover{background:#000;transform:translateY(-1px)}

/* big centered statement (studio-style intro) */
.statement{padding:76px 0;border-bottom:1px solid var(--line)}
.statement-inner{max-width:480px;margin:0 auto}
.statement-inner p{font-size:clamp(14px,1.3vw,16px);line-height:1.7;letter-spacing:0;
  margin:0 0 15px;color:var(--ink);font-weight:400}
.statement-inner p:last-child{margin-bottom:0;color:var(--ink);font-size:clamp(13px,1.1vw,14px)}
/* keep the "About" intro body the same size/colour as the welcome statement */
#about .prose p{font-size:clamp(14px,1.3vw,16px);line-height:1.7;color:var(--ink)}

/* small intro line above a list */
.list-intro{color:var(--muted);font-size:15.5px;margin:0 0 6px}

/* ---------- Home: content blocks ---------- */
.block{padding:64px 0;border-bottom:1px solid var(--line)}
.block.alt{background:var(--alt)}
.block-head{margin-bottom:30px}
.block-head h2{font-weight:700;letter-spacing:-.02em;font-size:clamp(30px,5.5vw,52px);margin:0;line-height:1.04}
.block-sub{display:block;margin-top:10px;color:var(--muted);font-size:15px;font-weight:500;letter-spacing:.01em}
.block-intro{color:var(--muted);margin:-12px 0 28px;max-width:62ch}
.prose.narrow{max-width:64ch}

/* chapter index — compact single-line rows that darken on hover (reference) */
.chapter-list{border-top:1px solid var(--line)}
.ch-row{display:flex;align-items:center;gap:20px;padding:12px 4px;line-height:1.25;
  border-bottom:1px solid var(--line);color:var(--muted);
  transition:color 1s cubic-bezier(.16,1,.3,1),padding-left 1s cubic-bezier(.16,1,.3,1)}
.ch-row:hover{color:var(--ink);padding-left:28px}
.ch-num{flex:none;min-width:7.5em;font-size:clamp(14px,1.5vw,17px);font-weight:400;
  letter-spacing:.01em;color:inherit}
.ch-title{flex:1;min-width:0;display:flex;align-items:baseline;gap:.65em;flex-wrap:wrap;
  font-size:clamp(17px,1.9vw,21px);font-weight:400;letter-spacing:-.01em;color:inherit}
.ch-zh-inline{font-size:.7em;opacity:.6}
.ch-arrow{flex:none;font-size:17px;color:inherit;opacity:.55;
  transition:opacity 1s cubic-bezier(.16,1,.3,1),transform 1s cubic-bezier(.16,1,.3,1)}
.ch-row:hover .ch-arrow{opacity:1;transform:translate(8px,-8px)}
/* mobile: stack "Chapter NN" on its own line, English then Chinese below */
@media (max-width:699px){
  .ch-row{flex-wrap:wrap;align-items:flex-start;gap:3px 12px;padding:16px 4px}
  .ch-num{flex:1 0 100%;min-width:0;font-size:12px;letter-spacing:.04em}
  .ch-title{flex:1 1 0;flex-direction:column;align-items:flex-start;gap:1px;font-size:18px;color:var(--ink)}
  .ch-zh-inline{font-size:13px;color:var(--muted);opacity:1}
  .ch-arrow{align-self:flex-start;margin-top:2px;color:var(--muted);opacity:1}
}

/* quick find — flat hairline grid */
.qf-grid{display:grid;grid-template-columns:1fr;gap:0;border-top:1px solid var(--line)}
.qf-card{display:flex;flex-direction:column;gap:4px;padding:20px 4px;
  border-bottom:1px solid var(--line);transition:.16s}
.qf-card:hover{padding-left:12px;background:var(--accent-soft)}
.qf-want{font-weight:600;font-size:16px}
.qf-where{color:var(--muted);font-size:13.5px;font-weight:500}

/* appendix chips — flat bordered pills */
.ap-chips{display:flex;flex-wrap:wrap;gap:8px}
.ap-chip{display:inline-flex;align-items:center;gap:8px;
  border:1px solid var(--line-strong);border-radius:999px;padding:10px 18px;
  font-size:14.5px;transition:.16s}
.ap-chip b{color:var(--muted);font-weight:600}
.ap-chip:hover{border-color:var(--ink)}

/* ---------- Reader (chapter / appendix) ---------- */
.reader{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.layout{display:block;padding:34px 0 10px}
.content{min-width:0;max-width:var(--read)}
.layout-solo{max-width:var(--read);margin:0 auto}
.ch-header{padding:18px 0 32px;border-bottom:1px solid var(--ink);margin-bottom:8px}
.ch-eyebrow{display:inline-block;color:var(--muted);font-weight:600;letter-spacing:.14em;
  text-transform:uppercase;font-size:12px;margin-bottom:18px}
.ch-header h1{font-weight:700;letter-spacing:-.025em;font-size:clamp(34px,7vw,64px);
  line-height:1.02;margin:0}
.ch-en{color:var(--muted);margin:14px 0 0;font-size:16px;letter-spacing:.01em;font-weight:500}
.ch-intro{margin:22px 0 0;color:var(--ink-soft);max-width:62ch;font-size:16px}

/* centered full-width chapter hero (reference style) */
.ch-hero{text-align:center;padding:32px 0 92px}
.ch-pill{display:inline-flex;align-items:center;background:var(--pill);color:var(--ink);
  border-radius:999px;padding:7px 16px;font-size:13px;font-weight:500;letter-spacing:.02em}
.ch-hero h1{font-weight:700;letter-spacing:-.03em;line-height:1.02;
  font-size:clamp(36px,6.5vw,72px);margin:20px 0 0}
.ch-zh-sub{color:var(--muted);margin:14px 0 0;font-size:16px;font-weight:500}
.ch-hero .ch-intro{margin:20px auto 0;text-align:center}

.section{padding:40px 0;border-bottom:1px solid var(--line);scroll-margin-top:88px}
.section:last-of-type{border-bottom:0}
.section-no{color:var(--muted);font-weight:600;font-size:14px;letter-spacing:.06em;
  font-variant-numeric:tabular-nums}
.section-title{font-weight:700;font-size:clamp(22px,4vw,30px);margin:6px 0 18px;
  line-height:1.2;letter-spacing:-.015em;scroll-margin-top:90px}
.prose p{margin:0 0 17px}
.prose .sub{font-weight:700;font-size:18px;margin:26px 0 8px;letter-spacing:-.01em}
.prose .bul,.prose .ord{margin:8px 0 20px;padding-left:1.2em}
.prose .bul li,.prose .ord li{margin:7px 0}
.prose .bul{list-style:none;padding-left:0}
.prose .bul li{position:relative;padding-left:1.4em}
.prose .bul li::before{content:"";position:absolute;left:.1em;top:.74em;
  width:5px;height:5px;border-radius:50%;background:var(--ink)}
.prose blockquote{margin:26px 0;padding:6px 0 6px 22px;border-left:2px solid var(--ink);
  font-size:clamp(19px,3vw,24px);line-height:1.4;letter-spacing:-.01em}
.prose blockquote cite{display:block;margin-top:10px;font-size:14px;color:var(--muted);font-style:normal}

/* callout / note — flat, hairline + left rule */
.note{background:var(--accent-soft);border:0;border-left:2px solid var(--ink);
  border-radius:0;padding:14px 0 14px 20px;margin:22px 0}
.note-tag{display:inline-block;font-weight:700;color:var(--ink);font-size:13px;
  letter-spacing:.02em;margin-bottom:4px}
.note p{margin:0;color:var(--ink-soft)}

/* checklist */
.checklist{margin:16px 0 22px}
.cl-title{font-weight:700;margin:16px 0 8px}
.checklist ul{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:1fr;gap:9px}
.checklist li{display:flex;align-items:flex-start;gap:11px;line-height:1.5}
.checklist .box{flex:none;width:18px;height:18px;margin-top:3px;border:1.5px solid var(--line-strong);
  border-radius:3px;background:var(--surface)}

/* tables — editorial: light header, hairline rows, no fills */
.table-wrap{margin:20px 0 24px;overflow-x:auto}
table{border-collapse:collapse;width:100%;font-size:14.5px;min-width:520px}
thead th{background:transparent;color:var(--ink);text-align:left;font-weight:700;
  padding:11px 16px 11px 0;white-space:nowrap;font-size:12px;letter-spacing:.06em;
  text-transform:uppercase;border-bottom:2px solid var(--ink)}
tbody td{padding:14px 16px 14px 0;border-bottom:1px solid var(--line);vertical-align:top;color:var(--ink-soft)}
tbody td:first-child{font-weight:600;color:var(--ink)}
tbody tr:last-child td{border-bottom:0}

/* prev / next — centered grey pills (reference) */
.prevnext{display:flex;justify-content:center;flex-wrap:wrap;gap:14px;margin-top:56px}
.pn{display:inline-flex;align-items:center;gap:9px;background:var(--pill);border:0;border-radius:999px;
  padding:12px 22px;font-size:15px;font-weight:500;color:var(--ink);transition:.15s}
.pn:hover{background:var(--pill-hover);transform:translateY(-1px)}
.pn-arr{color:var(--muted)}

/* ---------- Sidebar ---------- */
.sidebar{margin:0 0 8px}
.toc-chapter{display:inline-flex;align-items:center;gap:8px;max-width:100%;cursor:pointer;
  background:var(--pill);border:0;border-radius:999px;padding:9px 16px;margin-bottom:18px;
  font-family:var(--sans);font-size:13.5px;font-weight:500;color:var(--ink);transition:.15s}
.toc-chapter:hover{background:var(--pill-hover)}
.toc-chapter .chev{color:var(--muted);font-size:16px;line-height:1}
.toc-chapter-label{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.toc-details{border-bottom:1px solid var(--line);margin-bottom:10px;padding-bottom:6px}
.toc-details>summary{cursor:pointer;list-style:none;padding:12px 2px;font-weight:600;
  font-size:14px;display:flex;justify-content:space-between;align-items:center}
.toc-details>summary::-webkit-details-marker{display:none}
.toc-details>summary::after{content:"＋";color:var(--muted);font-weight:400}
.toc-details[open]>summary::after{content:"－"}
.toc-inner{list-style:none;margin:0;padding:2px 0 12px}
.on-this-page a{display:flex;gap:10px;padding:7px 12px;border-radius:999px;font-size:14px;color:var(--muted);line-height:1.4;transition:.15s}
.on-this-page a:hover{color:var(--ink)}
.on-this-page a>span{color:inherit}
.chapter-switch li{margin:0}
.chapter-switch a{display:flex;gap:9px;padding:7px 2px;font-size:14px;color:var(--muted);transition:.15s}
.chapter-switch a b{color:var(--muted);font-weight:600;font-variant-numeric:tabular-nums;min-width:1.6em}
.chapter-switch a:hover{color:var(--ink)}
.chapter-switch li.cur a{color:var(--ink);font-weight:600}
.chapter-switch li.cur a b{color:var(--ink)}

/* ---------- Footer ---------- */
.site-footer{background:var(--bg);color:var(--ink);margin-top:48px;padding:48px 24px 40px;border-top:1px solid var(--ink)}
.foot-grid{max-width:var(--maxw);margin:0 auto;display:flex;flex-wrap:wrap;
  justify-content:space-between;gap:24px;align-items:flex-start}
.foot-brand{font-weight:700;font-size:19px;margin:0;letter-spacing:-.01em}
.foot-sub{color:var(--muted);margin:6px 0 0;font-size:14px}
.foot-links{display:flex;flex-wrap:wrap;gap:20px}
.foot-links a{color:var(--ink);font-size:14.5px;border-bottom:1px solid transparent;padding-bottom:2px}
.foot-links a:hover{border-color:var(--ink)}
.foot-fine{max-width:var(--maxw);margin:32px auto 0;color:var(--muted);font-size:12.5px;
  border-top:1px solid var(--line);padding-top:20px}

/* ---------- Overlays (chapters + search) ---------- */
.overlay{position:fixed;inset:0;z-index:100;display:flex;justify-content:flex-end;
  background:rgba(15,15,15,.34);animation:fade .2s ease}
.overlay[hidden]{display:none}

/* full-screen Chapters takeover (matches reference) */
.overlay-full{display:block;background:var(--bg);overflow-y:auto;animation:fade .18s ease}
.overlay-full .full-inner{max-width:var(--maxw);margin:0 auto;padding:56px 24px 90px;position:relative}
.ov-close{position:absolute;top:44px;right:24px;width:48px;height:48px;border-radius:999px;
  background:var(--pill);border:0;color:var(--ink);font-size:24px;line-height:1;cursor:pointer;
  display:flex;align-items:center;justify-content:center;transition:.15s}
.ov-close:hover{background:var(--pill-hover)}
.full-head{margin-bottom:16px;padding-right:64px}
.full-title{font-weight:700;letter-spacing:-.03em;font-size:clamp(34px,6vw,58px);margin:0;line-height:1}
.full-sub{color:var(--muted);margin:12px 0 0;font-size:15.5px}
.full-group{margin:36px 0 0;color:var(--muted);font-size:12px;letter-spacing:.14em;
  text-transform:uppercase;font-weight:600}

.overlay-inner{background:var(--bg);width:min(460px,100%);height:100%;
  display:flex;flex-direction:column;border-left:1px solid var(--line);animation:slide .26s cubic-bezier(.2,.7,.2,1)}
.search-overlay .overlay-inner{width:min(620px,100%)}
.overlay-head{display:flex;align-items:center;gap:12px;justify-content:space-between;
  padding:18px 22px;border-bottom:1px solid var(--line)}
.overlay-title{font-weight:600;letter-spacing:.02em;font-size:14px;text-transform:uppercase;color:var(--muted)}
.icon-btn{background:none;border:0;font-size:26px;line-height:1;cursor:pointer;color:var(--ink);padding:0 4px}
.icon-btn:hover{color:var(--muted)}
.overlay-scroll{overflow-y:auto;padding:8px 22px 40px}
.ov-list{display:flex;flex-direction:column}
.ov-item{display:flex;align-items:baseline;gap:16px;padding:16px 4px;border-bottom:1px solid var(--line);transition:.15s}
.ov-item:hover{padding-left:10px}
.ov-num{font-weight:600;color:var(--muted);font-size:14px;flex:none;width:2.2em;font-variant-numeric:tabular-nums}
.ov-tt{display:flex;flex-direction:column}
.ov-zh{font-weight:600;font-size:16px;letter-spacing:-.01em}
.ov-en{color:var(--muted);font-size:12.5px}
.ov-section-label{margin:24px 4px 4px;color:var(--muted);font-size:11.5px;
  letter-spacing:.16em;text-transform:uppercase;font-weight:600}

/* search */
#searchInput{flex:1;border:0;background:transparent;font-family:var(--sans);
  font-size:18px;color:var(--ink);outline:none}
.search-hint{color:var(--muted);padding:14px 4px}
.search-results .res{display:block;padding:16px 4px;border-bottom:1px solid var(--line);transition:.15s}
.search-results .res:hover{padding-left:10px}
.res-crumb{color:var(--muted);font-size:12px;font-weight:600;letter-spacing:.03em}
.res-title{font-weight:600;font-size:16px;margin:3px 0;letter-spacing:-.01em}
.res-snip{color:var(--muted);font-size:13.5px;line-height:1.5}
.res mark{background:var(--mark);color:var(--ink);border-radius:2px;padding:0 1px}
.no-res{color:var(--muted);padding:16px 4px}

@keyframes fade{from{opacity:0}to{opacity:1}}
@keyframes slide{from{transform:translateX(28px);opacity:.4}to{transform:none;opacity:1}}

/* ============================================================
   TABLET  ≥ 700px
   ============================================================ */
@media (min-width:700px){
  .qf-grid{grid-template-columns:1fr 1fr;column-gap:40px}
  .checklist ul{grid-template-columns:1fr 1fr;column-gap:30px}
  .hero{padding:96px 0 64px}
}

/* ============================================================
   DESKTOP  ≥ 1040px — persistent sidebar
   ============================================================ */
@media (min-width:1040px){
  body{font-size:17px}
  .layout{display:grid;grid-template-columns:230px minmax(0,1fr);gap:72px;align-items:start;padding-top:48px}
  .layout-solo{display:block}
  .sidebar{position:sticky;top:96px;align-self:start;max-height:calc(100vh - 120px);overflow:auto;margin:0}
  .toc-details{border-bottom:0;padding-bottom:0;margin-bottom:22px}
  .toc-details>summary{display:none}
  .toc-details .toc-inner{display:block!important;padding:0}
  .switcher{border-top:1px solid var(--line);padding-top:18px}
  .switcher::before{content:"All chapters · 所有章節";display:block;color:var(--muted);font-size:11px;
    letter-spacing:.12em;text-transform:uppercase;font-weight:600;margin:0 2px 10px}
  .on-this-page::before{content:"On this page · 本頁內容";display:block;color:var(--muted);font-size:11px;
    letter-spacing:.12em;text-transform:uppercase;font-weight:600;margin:0 12px 8px}
  .content{max-width:var(--read)}
}

@media (min-width:1280px){
  .layout{grid-template-columns:240px minmax(0,1fr);gap:96px}
}