:root{
  --ink:#1b1b1f; --ink-soft:#3a3a42; --mut:#6b6b76; --faint:#9a9aa4;
  --paper:#fffdf8; --paper-edge:#f3efe6; --bg:#d9d6cf; --rule:#dcd7cc;
  --accent:#7a1f2b; --accent2:#0b3a5b; --link:#7a1f2b;
  --code-bg:#f4f1ea; --tip:#0b6b4f; --warn:#9a4a00; --sec:#5b2a86; --note:#274b8f;
  --serif:'Iowan Old Style','Palatino Linotype','Book Antiqua',Palatino,Georgia,'Times New Roman',serif;
  --sans:-apple-system,BlinkMacSystemFont,'Segoe UI',Helvetica,Arial,sans-serif;
  --mono:'SFMono-Regular',Menlo,Consolas,'Liberation Mono',monospace;
}
*{box-sizing:border-box}
html{ -webkit-text-size-adjust:100% }
body{
  margin:0; background:var(--bg);
  font-family:var(--serif); color:var(--ink);
  font-size:18px; line-height:1.62; text-rendering:optimizeLegibility;
  -webkit-font-smoothing:antialiased;
}
body[lang="ja"]{ font-family:'Hiragino Mincho ProN','Yu Mincho',YuMincho,var(--serif); }

/* paper page that floats on a desk */
.page{
  max-width:46rem; margin:28px auto; background:var(--paper);
  padding:64px 72px 80px; border-radius:2px;
  box-shadow:0 1px 0 var(--paper-edge), 0 18px 50px rgba(40,33,20,.18);
  position:relative;
}
.page::before{ /* binding edge */
  content:""; position:absolute; left:0; top:0; bottom:0; width:4px;
  background:linear-gradient(var(--accent),#52131c); border-radius:2px 0 0 2px;
}

/* top bar (screen only) */
.bar{ position:sticky; top:0; z-index:30; background:rgba(27,27,31,.96);
  color:#f4f1ea; font-family:var(--sans); font-size:13px; }
.bar .in{ max-width:60rem; margin:0 auto; padding:9px 18px; display:flex; gap:18px; align-items:center; }
.bar a{ color:#e8e2d4; text-decoration:none; opacity:.85 }
.bar a:hover{ opacity:1; color:#fff }
.bar .sp{ flex:1 }
.bar b{ color:#fff; font-weight:600; letter-spacing:.02em }
.bar .pill{ border:1px solid rgba(255,255,255,.25); border-radius:20px; padding:3px 11px }

/* ---- SEARCH (screen only) ---- */
.srch{ position:relative; font-family:var(--sans) }
.srch input{ font-family:inherit; font-size:13px; color:#f4f1ea; width:13rem; max-width:38vw;
  background:rgba(255,255,255,.1); border:1px solid rgba(255,255,255,.22); border-radius:20px;
  padding:5px 12px 5px 28px; outline:none; transition:width .16s ease, background .16s ease }
.srch input::placeholder{ color:rgba(244,241,234,.55) }
.srch input:focus{ width:17rem; background:rgba(255,255,255,.16); border-color:rgba(255,255,255,.45) }
.srch::before{ content:"⌕"; position:absolute; left:9px; top:50%; transform:translateY(-52%);
  font-size:15px; color:rgba(244,241,234,.6); pointer-events:none }
.srch .res{ display:none; position:absolute; right:0; top:calc(100% + 7px); width:26rem; max-width:88vw;
  background:var(--paper); color:var(--ink); border:1px solid var(--rule); border-radius:9px;
  box-shadow:0 16px 44px rgba(20,16,8,.34); overflow:hidden; max-height:70vh; overflow-y:auto; z-index:40 }
.srch.open .res{ display:block }
.srch .res a{ display:block; border:0; padding:9px 14px; border-bottom:1px solid var(--rule); color:var(--ink) }
.srch .res a:last-child{ border-bottom:0 }
.srch .res a:hover,.srch .res a.sel{ background:#f4efe4 }
.srch .res .ch{ font-size:10.5px; letter-spacing:.13em; text-transform:uppercase; color:var(--accent); font-weight:700 }
.srch .res .ti{ font-size:14.5px; font-weight:650; margin:1px 0 2px; color:var(--ink) }
.srch .res .sn{ font-size:12.5px; color:var(--mut); line-height:1.45;
  display:-webkit-box; -webkit-line-clamp:2; -webkit-box-orient:vertical; overflow:hidden }
.srch .res mark,.searchpage mark{ background:#fbe7a3; color:inherit; border-radius:2px; padding:0 1px }
.srch .res .empty,.srch .res .more{ padding:11px 14px; font-size:13px; color:var(--mut) }
.srch .res .more{ border-top:1px solid var(--rule); color:var(--accent); font-weight:650; text-align:center }

/* dedicated results page */
.searchpage .sbox{ margin:0 0 26px }
.searchpage .sbox input{ font-family:var(--sans); font-size:19px; width:100%; padding:13px 18px;
  border:1px solid var(--rule); border-radius:9px; background:#fbf9f3; color:var(--ink); outline:none }
.searchpage .sbox input:focus{ border-color:var(--accent2); background:#fff }
.searchpage .hint{ font-family:var(--sans); font-size:13.5px; color:var(--mut); margin:10px 2px 0 }
.searchpage .count{ font-family:var(--sans); font-size:13px; letter-spacing:.1em; text-transform:uppercase;
  color:var(--faint); font-weight:700; margin:26px 0 10px; border-bottom:1px solid var(--rule); padding-bottom:7px }
.searchpage .hit{ display:block; border:0; color:var(--ink); padding:13px 0; border-bottom:1px solid var(--rule) }
.searchpage .hit:hover{ background:#faf7ef }
.searchpage .hit .ch{ font-family:var(--sans); font-size:11px; letter-spacing:.13em; text-transform:uppercase;
  color:var(--accent); font-weight:700 }
.searchpage .hit .ti{ font-family:var(--sans); font-size:18px; font-weight:650; margin:2px 0 4px }
.searchpage .hit .sn{ font-size:15.5px; color:var(--ink-soft); line-height:1.5 }
/* the target section, after arriving from a search hit */
.body :target{ animation:sflash 2.4s ease-out 1 }
@keyframes sflash{ 0%,55%{ background:#fbe7a3 } 100%{ background:transparent } }

/* typography */
h1,h2,h3,h4{ font-family:var(--sans); color:var(--ink); line-height:1.2; font-weight:650 }
.page p{ margin:0 0 1em; hyphens:auto }
.page p+p{ }
a{ color:var(--link); text-decoration:none; border-bottom:1px solid rgba(122,31,43,.28) }
a:hover{ border-bottom-color:var(--link) }
strong,b{ font-weight:650 }
code,kbd{ font-family:var(--mono); font-size:.86em; background:var(--code-bg);
  padding:1px 6px; border-radius:4px; color:#5a2b2f; }
kbd{ border:1px solid #ddd6c8; box-shadow:0 1px 0 #ccc4b3; background:#fbf9f4; }
pre{ font-family:var(--mono); font-size:.82em; line-height:1.5; background:#23232a; color:#eceae3;
  padding:16px 18px; border-radius:7px; overflow:auto; margin:1.1em 0 }
pre code{ background:none; color:inherit; padding:0 }

/* ---- COVER ---- */
.cover{ min-height:calc(100vh - 56px); display:flex; align-items:center; justify-content:center;
  padding:40px 16px; }
.cover .card{ max-width:42rem; width:100%; background:linear-gradient(170deg,#2a0d12,#160a1f 60%,#0b1f33);
  color:#f7f2e8; border-radius:6px; padding:72px 60px 56px; position:relative; overflow:hidden;
  box-shadow:0 30px 70px rgba(0,0,0,.4); }
.cover .card::after{ content:""; position:absolute; inset:14px; border:1px solid rgba(247,242,232,.22); border-radius:3px; pointer-events:none }
.cover .logo{ width:74px; height:74px; border-radius:17px; display:block; margin-bottom:30px; box-shadow:0 8px 24px rgba(0,0,0,.4) }
.cover .kicker{ font-family:var(--sans); letter-spacing:.34em; text-transform:uppercase; font-size:12px; color:#d9b8b0; margin:0 0 14px }
.cover h1{ font-family:var(--serif); font-weight:600; font-size:60px; line-height:1.02; margin:0 0 6px; color:#fff }
.cover .ed{ font-family:var(--serif); font-style:italic; font-size:26px; color:#e7d6c2; margin:0 0 28px }
.cover .sub{ font-size:18px; color:#e9e1d2; max-width:30rem; margin:0 0 40px; line-height:1.5 }
.cover .meta{ font-family:var(--sans); font-size:13px; color:#cdbfae; letter-spacing:.03em; border-top:1px solid rgba(247,242,232,.2); padding-top:20px }
.cover .meta b{ color:#fff }
.cover .actions{ margin-top:34px; display:flex; gap:12px; flex-wrap:wrap }
.cover .btn{ font-family:var(--sans); font-size:14px; font-weight:600; padding:11px 20px; border-radius:8px;
  background:#f7f2e8; color:#2a0d12; border:0; }
.cover .btn.ghost{ background:transparent; color:#f7f2e8; border:1px solid rgba(247,242,232,.4) }

/* ---- FRONT MATTER ---- */
.front .titlepage{ text-align:center; padding:40px 0 24px; border-bottom:2px solid var(--ink); margin-bottom:30px }
.front .titlepage .t{ font-family:var(--serif); font-size:44px; font-weight:600; margin:0 }
.front .titlepage .s{ font-family:var(--serif); font-style:italic; font-size:22px; color:var(--mut); margin:6px 0 0 }
.legal{ font-size:14px; color:var(--mut); line-height:1.6 }
.legal h3{ font-size:13px; letter-spacing:.12em; text-transform:uppercase; color:var(--faint); margin:26px 0 8px }

/* ---- TABLE OF CONTENTS ---- */
.toc h1{ font-family:var(--serif); font-weight:600; font-size:40px; margin:0 0 6px }
.toc .partline{ font-family:var(--sans); font-weight:700; font-size:13px; letter-spacing:.16em;
  text-transform:uppercase; color:var(--accent); margin:30px 0 10px; padding-bottom:6px; border-bottom:1px solid var(--rule) }
.toc ol{ list-style:none; margin:0; padding:0 }
.toc li{ display:flex; align-items:baseline; gap:8px; margin:7px 0; font-size:17px }
.toc .num{ font-family:var(--sans); font-weight:650; color:var(--accent2); min-width:2.1em }
.toc .ttl{ white-space:nowrap; overflow:hidden; text-overflow:ellipsis }
.toc .dots{ flex:1; border-bottom:2px dotted #cdc6b6; transform:translateY(-4px); margin:0 4px }
.toc .pg{ font-family:var(--sans); color:var(--mut); font-size:14px }
.toc a{ border:0; color:var(--ink) }
.toc a:hover{ color:var(--accent) }

/* ---- PART DIVIDER ---- */
.partdiv{ min-height:60vh; display:flex; flex-direction:column; justify-content:center; text-align:center; padding:40px 0 }
.partdiv .pk{ font-family:var(--sans); letter-spacing:.34em; text-transform:uppercase; font-size:13px; color:var(--accent); margin:0 0 10px }
.partdiv .pn{ font-family:var(--serif); font-size:90px; line-height:1; color:var(--paper-edge); -webkit-text-stroke:1.5px var(--accent); margin:0 0 14px }
.partdiv h1{ font-family:var(--serif); font-weight:600; font-size:42px; margin:0 auto 16px; max-width:24rem }
.partdiv .pd{ color:var(--mut); max-width:30rem; margin:0 auto; font-size:18px }
.partdiv ol{ text-align:left; max-width:26rem; margin:34px auto 0; padding:0; list-style:none; border-top:1px solid var(--rule) }
.partdiv ol li{ padding:9px 2px; border-bottom:1px solid var(--rule); font-size:16px; display:flex; gap:12px }
.partdiv ol li .n{ font-family:var(--sans); color:var(--accent2); font-weight:650; min-width:1.6em }
.partdiv ol li a{ border:0; color:var(--ink) }

/* ---- CHAPTER OPENER ---- */
.chopen{ border-bottom:2px solid var(--ink); padding-bottom:22px; margin-bottom:30px }
.chopen .ck{ font-family:var(--sans); letter-spacing:.28em; text-transform:uppercase; font-size:12px; color:var(--accent); margin:0 0 4px }
.chopen .cn{ font-family:var(--serif); font-size:78px; line-height:.9; color:var(--paper-edge);
  -webkit-text-stroke:1.5px var(--accent2); float:right; margin:-6px 0 0 18px }
.chopen h1{ font-family:var(--serif); font-weight:600; font-size:46px; line-height:1.05; margin:6px 0 0; max-width:30rem }
.chopen .lede{ font-size:20px; color:var(--ink-soft); font-style:italic; margin:16px 0 0; clear:right }

/* in-this-chapter box */
.chnav{ background:#f6f2e9; border:1px solid var(--rule); border-radius:8px; padding:16px 20px; margin:0 0 34px;
  font-family:var(--sans) }
.chnav .h{ font-size:11px; letter-spacing:.16em; text-transform:uppercase; color:var(--accent); font-weight:700; margin:0 0 8px }
.chnav ul{ margin:0; padding:0; list-style:none; columns:2; column-gap:28px; font-size:14.5px }
.chnav li{ padding:3px 0; break-inside:avoid }
.chnav a{ border:0; color:var(--ink-soft) }
.chnav a:hover{ color:var(--accent) }

/* headings inside chapters, auto-numbered */
.body h2{ font-size:27px; margin:1.9em 0 .5em; padding-top:.2em; }
.body h3{ font-size:21px; margin:1.6em 0 .4em; color:var(--ink-soft) }
.body h4{ font-size:17px; margin:1.3em 0 .3em; font-family:var(--sans); color:var(--accent2); letter-spacing:.01em }
.body h2 .secno{ color:var(--accent); font-family:var(--sans); font-weight:700; margin-right:.5em }
.body h3 .secno{ color:var(--accent2); font-family:var(--sans); font-weight:650; margin-right:.5em; font-size:.9em }
.body ul,.body ol{ margin:0 0 1.1em; padding-left:1.3em }
.body li{ margin:.32em 0 }
.body ul.tight li{ margin:.12em 0 }
.body blockquote{ margin:1.3em 0; padding:6px 0 6px 22px; border-left:3px solid var(--accent);
  font-style:italic; color:var(--ink-soft); font-size:19px }
.body table{ border-collapse:collapse; width:100%; font-size:15.5px; font-family:var(--sans); margin:1.2em 0 }
.body th,.body td{ text-align:left; padding:8px 11px; border-bottom:1px solid var(--rule); vertical-align:top }
.body th{ background:#f4f0e7; font-weight:650; color:var(--ink); border-bottom:2px solid #d8d1c2 }
.body td code{ font-size:.9em }
.body hr{ border:0; border-top:1px solid var(--rule); margin:2em 0 }
.lead::first-letter{ /* drop cap on the first paragraph of a chapter */
  font-family:var(--serif); float:left; font-size:3.4em; line-height:.82; padding:.04em .08em 0 0; color:var(--accent) }

/* ---- CALLOUT BOXES ---- */
.box{ font-family:var(--sans); font-size:15.5px; line-height:1.55; border-radius:8px; padding:14px 18px 14px 46px;
  margin:1.4em 0; position:relative; border:1px solid; }
.box .bt{ font-weight:700; display:block; margin-bottom:3px; letter-spacing:.02em }
.box::before{ position:absolute; left:15px; top:13px; font-size:18px; line-height:1 }
.box p{ margin:.3em 0 }
.box.note{ background:#eef3fb; border-color:#cdddf3; color:#22324c } .box.note::before{ content:"ℹ︎"; color:var(--note) } .box.note .bt{ color:var(--note) }
.box.tip{ background:#ecf7f1; border-color:#cde9da; color:#1f3d31 } .box.tip::before{ content:"✦"; color:var(--tip) } .box.tip .bt{ color:var(--tip) }
.box.warn{ background:#fbf3e8; border-color:#f0ddc0; color:#4a3413 } .box.warn::before{ content:"▲"; color:var(--warn) } .box.warn .bt{ color:var(--warn) }
.box.sec{ background:#f4eefb; border-color:#e0cdf3; color:#352247 } .box.sec::before{ content:"⛨"; color:var(--sec) } .box.sec .bt{ color:var(--sec) }

/* "key concept" sidebar */
.aside{ font-family:var(--sans); font-size:15px; background:#fbf9f3; border:1px solid var(--rule);
  border-top:3px solid var(--accent2); border-radius:0 0 8px 8px; padding:14px 18px; margin:1.5em 0 }
.aside .h{ font-size:11px; letter-spacing:.14em; text-transform:uppercase; color:var(--accent2); font-weight:700; margin:0 0 6px }

/* steps */
ol.steps{ counter-reset:st; list-style:none; padding-left:0 }
ol.steps>li{ position:relative; padding:2px 0 14px 46px; margin:0; border-left:1px solid var(--rule); margin-left:14px }
ol.steps>li::before{ counter-increment:st; content:counter(st); position:absolute; left:-14px; top:0;
  width:28px; height:28px; border-radius:50%; background:var(--accent2); color:#fff; font-family:var(--sans);
  font-weight:700; font-size:14px; display:flex; align-items:center; justify-content:center }
ol.steps>li:last-child{ border-left-color:transparent }

/* ---- FIGURES ---- */
figure.fig{ margin:1.7em 0; }
figure.fig .frame{ border:1px solid #d7d0c0; background:#fbfaf6; border-radius:8px; padding:8px;
  box-shadow:0 3px 14px rgba(40,33,20,.08) }
figure.fig img{ width:100%; display:block; border-radius:4px }
figure.fig .ph{ aspect-ratio:16/10; border:2px dashed #cdc4b2; border-radius:5px; background:
  repeating-linear-gradient(45deg,#f6f3ea,#f6f3ea 12px,#f1ede2 12px,#f1ede2 24px);
  display:flex; align-items:center; justify-content:center; color:var(--faint);
  font-family:var(--sans); font-size:13px; letter-spacing:.08em; text-transform:uppercase }
figure.fig figcaption{ font-family:var(--sans); font-size:14px; color:var(--mut); margin-top:9px; line-height:1.45 }
figure.fig figcaption .fn{ font-weight:700; color:var(--ink) }
figure.fig figcaption .cap{ display:block; margin-top:4px; font-size:12.5px; color:var(--faint); font-style:italic }
figure.fig figcaption .cap b{ font-style:normal; color:var(--accent2); letter-spacing:.06em; text-transform:uppercase; font-size:11px }

/* keyboard-style service grid for catalog */
.catgrid{ columns:2; column-gap:30px; font-family:var(--sans); font-size:15px; margin:1em 0 }
.catgrid .cat{ break-inside:avoid; margin:0 0 16px }
.catgrid .cat h4{ margin:0 0 4px; font-size:15px; color:var(--accent); font-family:var(--sans) }
.catgrid .cat p{ margin:0; font-size:14px; color:var(--mut); line-height:1.45 }

/* footer nav (screen) */
.pager{ display:flex; justify-content:space-between; gap:14px; margin-top:54px; padding-top:22px;
  border-top:1px solid var(--rule); font-family:var(--sans); font-size:14px }
.pager a{ border:0; max-width:46%; color:var(--ink) }
.pager .lbl{ display:block; font-size:11px; letter-spacing:.12em; text-transform:uppercase; color:var(--faint) }
.pager .t{ color:var(--accent); font-weight:600 }
.pager .next{ text-align:right; margin-left:auto }

.foot{ text-align:center; font-family:var(--sans); font-size:12.5px; color:var(--faint); margin:18px auto 50px }

@media (max-width:720px){
  body{ font-size:17px }
  .page{ padding:34px 22px 50px; margin:10px 8px }
  .cover .card{ padding:48px 30px } .cover h1{ font-size:42px }
  .chopen h1{ font-size:34px } .chopen .cn{ font-size:54px }
  .chnav ul{ columns:1 } .catgrid{ columns:1 }
  .toc li{ font-size:15px }
}

/* ============================ PRINT ============================ */
@media print{
  @page{ size:170mm 244mm; margin:20mm 18mm 22mm; }
  @page{ @bottom-center{ content:counter(page); font-family:var(--sans); font-size:9pt; color:#666 } }
  html,body{ background:#fff; color:#000; font-size:11.2pt }
  .bar,.pager,.foot,.cover .actions,.bar *,.srch,.searchpage .sbox{ display:none !important }
  .page{ max-width:none; margin:0; padding:0; box-shadow:none; border-radius:0 }
  .page::before{ display:none }
  a{ color:#000; border:0 }
  .chopen,.partdiv,.cover,.front .titlepage{ break-after:auto }
  .chapter, .partdiv-wrap, .frontmatter, .toc, .cover{ break-before:page }
  .body h2,.body h3,.body h4{ break-after:avoid }
  figure.fig,.box,.aside,table,pre{ break-inside:avoid }
  .cover .card{ background:#fff !important; color:#000 !important; box-shadow:none; border:1px solid #000 }
  .cover .kicker,.cover h1,.cover .ed,.cover .sub,.cover .meta,.cover .meta b{ color:#000 !important }
  .cover .card::after{ border-color:#000 }
  .chopen .cn,.partdiv .pn{ -webkit-text-stroke:1.2px #000; color:#fff }
  pre{ background:#f3f3f3; color:#000; border:1px solid #ccc }
  .box{ border-color:#999 !important; background:#f6f6f6 !important; color:#000 !important }
}