/* ==========================================================================
   BD Holding — AI Prompt Library
   ========================================================================== */
:root {
  --ink: #0f0f0f;
  --paper: #f4f3ef;
  --accent: #b0916a;
  --accent-soft: rgba(176, 145, 106, .24);
  --header: 72px;
  --footer: 64px;
  --pad-x: clamp(20px, 6vw, 120px);
  --ease: cubic-bezier(.16, 1, .3, 1);
  --ease-io: cubic-bezier(.65, 0, .35, 1);
  --font-body: 'DM Sans', system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  --font-head: 'Manrope', 'DM Sans', system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  /* media height inside split layouts: fills what the viewport leaves */
  --media-h: clamp(220px, calc(100dvh - var(--header) - var(--footer) - 210px), 640px);
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; height: 100%; overflow: hidden; }
body {
  font-family: var(--font-body);
  background: var(--ink);
  color: #f2f1ed;
  font-synthesis: none;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
h1, h2, h3, p, figure, blockquote { margin: 0; }
h1, h2, h3 { font-family: var(--font-head); font-weight: 500; }
img { max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; padding: 0; cursor: pointer; -webkit-tap-highlight-color: transparent; }
a { color: inherit; text-decoration: none; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
button:disabled { opacity: .25; cursor: default; }
[hidden] { display: none !important; }
svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; flex: none; }
kbd { font-family: var(--font-body); font-size: 11px; line-height: 1; padding: 3px 6px; border: 1px solid rgba(255,255,255,.22); border-bottom-width: 2px; margin: 0 2px; color: #cfcfcf; }

/* ---------- Loader ---------- */
#loader { position: fixed; inset: 0; z-index: 100; background: var(--ink); display: grid; place-content: center; justify-items: center; gap: 26px; transition: opacity .7s var(--ease), visibility .7s; }
#loader img { width: 170px; opacity: .92; }
.loader-bar { width: 170px; height: 1px; background: rgba(255,255,255,.14); overflow: hidden; }
.loader-bar i { display: block; height: 100%; width: 40%; background: var(--accent); animation: load 1.1s var(--ease-io) infinite; }
@keyframes load { from { transform: translateX(-100%); } to { transform: translateX(260%); } }
body.ready #loader { opacity: 0; visibility: hidden; }

/* ---------- Shared chrome ---------- */
.label { font-size: 11px; font-weight: 600; letter-spacing: .16em; text-transform: uppercase; color: var(--muted, #9d9d9d); }
.icon-btn { width: 40px; height: 40px; display: inline-grid; place-items: center; color: inherit; transition: background .25s, color .25s; }
.icon-btn:hover:not(:disabled) { background: rgba(255,255,255,.08); }

.btn, .btn-ghost { display: inline-flex; align-items: center; gap: 10px; min-height: 44px; padding: 0 20px; font-size: 14px; font-weight: 500; letter-spacing: .01em; transition: background .3s var(--ease), color .3s var(--ease), border-color .3s var(--ease), transform .3s var(--ease); white-space: nowrap; }
.btn { background: var(--fg, #f2f1ed); color: var(--bg, #0f0f0f); border: 1px solid var(--fg, #f2f1ed); }
.btn:hover { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn-ghost { border: 1px solid var(--line-strong, rgba(255,255,255,.28)); color: var(--fg, #f2f1ed); }
.btn-ghost:hover { border-color: var(--fg, #f2f1ed); }
.btn:active, .btn-ghost:active { transform: scale(.98); }
.btn svg, .btn-ghost svg { width: 16px; height: 16px; }
.sm { min-height: 34px; padding: 0 13px; font-size: 13px; gap: 7px; }

.topbar { position: fixed; top: 0; left: 0; right: 0; z-index: 20; height: calc(var(--header) + env(safe-area-inset-top, 0px)); padding: env(safe-area-inset-top, 0px) var(--pad-x) 0; display: flex; align-items: center; justify-content: space-between; gap: 24px; background: rgba(15,15,15,.78); backdrop-filter: blur(16px) saturate(1.3); -webkit-backdrop-filter: blur(16px) saturate(1.3); border-bottom: 1px solid rgba(255,255,255,.08); }
.wordmark img { display: block; height: 42px; width: auto; }
.chapters { display: flex; gap: 4px; }
.chapters button { position: relative; padding: 10px 14px; font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: #8d8d8d; transition: color .3s; }
.chapters button::after { content: ''; position: absolute; left: 14px; right: 14px; bottom: 2px; height: 1px; background: var(--accent); transform: scaleX(0); transform-origin: left; transition: transform .5s var(--ease); }
.chapters button:hover { color: #e6e6e6; }
.chapters button[aria-current] { color: #fff; }
.chapters button[aria-current]::after { transform: scaleX(1); }
.header-actions { display: flex; align-items: center; gap: 6px; }
.menu-btn { display: inline-flex; align-items: center; gap: 12px; height: 40px; padding: 0 6px 0 14px; font-size: 14px; transition: background .25s; }
.menu-btn:hover { background: rgba(255,255,255,.08); }

.bottom-bar { position: fixed; left: 0; right: 0; bottom: 0; z-index: 20; height: calc(var(--footer) + env(safe-area-inset-bottom, 0px)); padding: 0 var(--pad-x) env(safe-area-inset-bottom, 0px); display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; background: rgba(15,15,15,.78); backdrop-filter: blur(16px) saturate(1.3); -webkit-backdrop-filter: blur(16px) saturate(1.3); border-top: 1px solid rgba(255,255,255,.08); }
.progress-track { position: absolute; top: -1px; left: 0; right: 0; height: 2px; }
#progress { height: 100%; background: var(--accent); transform: scaleX(0); transform-origin: left; will-change: transform; }
.footer-title { font-size: 12px; color: #9a9a9a; letter-spacing: .02em; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.footer-title #chapter { color: #d9d9d9; }
.footer-title .sep { margin: 0 10px; color: #555; }
.slide-controls { display: flex; align-items: center; gap: 8px; }
.counter { min-width: 64px; text-align: center; font-size: 14px; font-variant-numeric: tabular-nums; }
.counter-total { color: #6f6f6f; }
.kbd-hint { justify-self: end; font-size: 11px; color: #7d7d7d; letter-spacing: .02em; white-space: nowrap; }

.dots { position: fixed; right: max(14px, calc(var(--pad-x) / 2 - 11px)); top: 50%; transform: translateY(-50%); z-index: 15; display: flex; flex-direction: column; mix-blend-mode: difference; }
.dots button { position: relative; width: 22px; height: 14px; display: grid; place-items: center; }
.dots button::before { content: ''; width: 4px; height: 4px; border-radius: 50%; background: #fff; opacity: .32; transition: transform .45s var(--ease), opacity .3s; }
.dots button:hover::before { opacity: .8; transform: scale(1.5); }
.dots button.on::before { opacity: 1; transform: scale(2); }
.dots span { position: absolute; right: 26px; top: 50%; transform: translate(6px, -50%); white-space: nowrap; font-size: 11px; letter-spacing: .06em; color: #fff; opacity: 0; pointer-events: none; transition: opacity .25s, transform .4s var(--ease); }
.dots button:hover span, .dots button:focus-visible span { opacity: 1; transform: translate(0, -50%); }

#toast { position: fixed; left: 50%; bottom: calc(var(--footer) + 20px); z-index: 60; transform: translate(-50%, 12px); padding: 12px 18px; background: #f2f1ed; color: #111; font-size: 14px; display: flex; gap: 10px; align-items: center; opacity: 0; pointer-events: none; transition: opacity .3s, transform .45s var(--ease); box-shadow: 0 18px 50px rgba(0,0,0,.35); }
#toast.visible { opacity: 1; transform: translate(-50%, 0); }
#toast svg { width: 16px; height: 16px; color: var(--accent); stroke-width: 2.2; }

/* ---------- Deck & slides ---------- */
#deck { position: relative; height: 100dvh; overflow-y: auto; overflow-x: hidden; scrollbar-width: none; overscroll-behavior: contain; }
#deck::-webkit-scrollbar { display: none; }

.slide {
  --bg: var(--ink); --fg: #f2f1ed; --muted: #a0a0a0; --line: rgba(255,255,255,.11); --line-strong: rgba(255,255,255,.28); --surface: rgba(255,255,255,.035); --surface-2: rgba(255,255,255,.07);
  position: relative; min-height: 100dvh; display: flex; align-items: center; isolation: isolate; overflow: hidden;
  padding: calc(var(--header) + clamp(18px, 4.2vh, 56px)) var(--pad-x) calc(var(--footer) + clamp(18px, 3.8vh, 52px));
  background: var(--bg); color: var(--fg);
}
.slide.light { --bg: var(--paper); --fg: #121212; --muted: #5f5f5f; --line: rgba(0,0,0,.11); --line-strong: rgba(0,0,0,.3); --surface: #fff; --surface-2: rgba(0,0,0,.045); color-scheme: light; }
.slide::before { content: ''; position: absolute; inset: 0; z-index: -2; pointer-events: none; background: repeating-linear-gradient(90deg, transparent 0 calc(25% - 1px), var(--surface) calc(25% - 1px) 25%); opacity: .7; }
.slide.light::before { background: repeating-linear-gradient(90deg, transparent 0 calc(25% - 1px), rgba(0,0,0,.035) calc(25% - 1px) 25%); }
.slide-inner { width: 100%; max-width: 1480px; margin: 0 auto; }

.eyebrow { display: flex; align-items: center; gap: 12px; font-size: 11px; font-weight: 600; letter-spacing: .18em; text-transform: uppercase; color: var(--muted); }
.eyebrow b { font-weight: 600; color: var(--accent); }
.eyebrow i { width: 26px; height: 1px; background: var(--line-strong); }
h1 { font-size: clamp(54px, min(7vw, 12.5vh), 128px); line-height: .98; letter-spacing: -.055em; }
h2 { font-size: clamp(28px, min(2.75vw, 5.6vh), 54px); line-height: 1.08; letter-spacing: -.04em; margin: clamp(10px, 1.8vh, 18px) 0; max-width: 24ch; text-wrap: balance; }
h3 { font-size: clamp(16px, min(1.2vw, 2.4vh), 20px); line-height: 1.3; letter-spacing: -.02em; font-weight: 600; }
.lead { font-size: clamp(15px, min(1.15vw, 2.35vh), 19px); line-height: 1.6; color: var(--muted); max-width: 62ch; text-wrap: pretty; }
.slide-head { margin-bottom: clamp(16px, 3.4vh, 40px); }
.slide-inner > .slide-head h2 { max-width: 48ch; }
.slide-inner > .slide-head .lead { max-width: 80ch; }

/* reveal choreography */
.reveal { opacity: 0; transform: translate3d(0, 22px, 0); transition: opacity .35s ease, transform .5s var(--ease); }
.slide.active .reveal { opacity: 1; transform: none; transition: opacity .9s var(--ease), transform 1.1s var(--ease); }
.slide.active .d1 { transition-delay: .07s; }
.slide.active .d2 { transition-delay: .15s; }
.slide.active .d3 { transition-delay: .24s; }

/* split layout */
.split { display: grid; grid-template-columns: minmax(0, .92fr) minmax(0, 1.08fr); gap: clamp(28px, 5vw, 96px); align-items: center; }
.split-text .slide-head { margin-bottom: clamp(12px, 2.6vh, 30px); }

/* numbered points */
.points { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.points li { display: grid; grid-template-columns: 34px 1fr; align-items: baseline; padding: clamp(8px, 1.45vh, 14px) 0; border-bottom: 1px solid var(--line); transition: padding .4s var(--ease); }
.points li span { font-size: 11px; color: var(--accent); font-variant-numeric: tabular-nums; letter-spacing: .06em; }
.points li p { font-size: clamp(14px, min(1.04vw, 2.2vh), 17px); line-height: 1.55; color: var(--fg); opacity: .86; }
.points li:hover { padding-left: 6px; }
.points li:hover p { opacity: 1; }

.note { margin-top: clamp(14px, 2.6vh, 28px); padding-left: 16px; border-left: 2px solid var(--accent); font-size: clamp(13px, min(.95vw, 2vh), 15px); line-height: 1.6; color: var(--muted); max-width: 64ch; }
.callout { margin-top: clamp(14px, 2.6vh, 26px); padding: clamp(14px, 2.2vh, 20px) 20px; background: var(--surface-2); border-left: 2px solid var(--accent); }
.callout strong { display: block; font-family: var(--font-head); font-weight: 600; font-size: clamp(15px, 1.15vw, 18px); letter-spacing: -.01em; margin-bottom: 6px; }
.callout p { font-size: 14px; line-height: 1.55; color: var(--muted); }

.card { background: var(--surface); border: 1px solid var(--line); padding: clamp(16px, 2.6vh, 26px); }

/* ---------- Media viewer ---------- */
.panel { position: relative; }
.tabs { position: relative; display: flex; gap: 26px; border-bottom: 1px solid var(--line); margin-bottom: 14px; }
.tabs button { padding: 0 0 12px; font-size: 13px; letter-spacing: .02em; color: var(--muted); transition: color .3s; }
.tabs button[aria-selected="true"], .tabs button:hover { color: var(--fg); }
.tab-ink { position: absolute; left: 0; bottom: -1px; height: 1px; width: 0; background: var(--fg); transition: transform .5s var(--ease), width .5s var(--ease); }
.tab-panes { display: grid; }
.tab-pane { grid-area: 1 / 1; min-width: 0; transition: opacity .45s var(--ease), transform .55s var(--ease), visibility .45s; }
.tab-pane:not(.on) { opacity: 0; visibility: hidden; transform: translateY(8px); pointer-events: none; }

.media { display: grid; gap: 10px; }
.media-main { position: relative; display: block; width: 100%; overflow: hidden; background: var(--surface-2); cursor: zoom-in; }
.media-main img { display: block; width: 100%; height: var(--media-h); object-fit: cover; transition: transform 1.2s var(--ease), opacity .3s ease; }
.media-main:hover img { transform: scale(1.025); }
.media-main img.swap { opacity: 0; }
.media-main::after { content: ''; position: absolute; inset: 0; box-shadow: inset 0 0 0 1px var(--line); pointer-events: none; }
.media-count { position: absolute; right: 12px; bottom: 12px; padding: 5px 9px; font-size: 11px; letter-spacing: .08em; background: rgba(15,15,15,.72); color: #cfcfcf; backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); }
.media-count b { color: #fff; font-weight: 600; }
.media-thumbs { display: grid; grid-template-columns: repeat(var(--n, 4), minmax(0, 1fr)); gap: 10px; }
.media-thumbs button { position: relative; overflow: hidden; background: var(--surface-2); }
.media-thumbs img { display: block; width: 100%; height: clamp(46px, 8.2vh, 86px); object-fit: cover; opacity: .5; filter: grayscale(.5); transition: opacity .4s, filter .4s; }
.media-thumbs button::after { content: ''; position: absolute; left: 0; right: 0; bottom: 0; height: 2px; background: var(--accent); transform: scaleX(0); transform-origin: left; transition: transform .5s var(--ease); }
.media-thumbs button:hover img { opacity: .85; filter: none; }
.media-thumbs button[aria-selected="true"] img { opacity: 1; filter: none; }
.media-thumbs button[aria-selected="true"]::after { transform: scaleX(1); }
.caption { margin-top: 10px; font-size: 12px; line-height: 1.5; color: var(--muted); }

/* prompt card */
.prompt-card { background: var(--surface); border: 1px solid var(--line); padding: clamp(16px, 2.6vh, 26px); }
.prompt-top { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 14px; flex-wrap: wrap; }
.prompt-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.prompt-text { font-size: clamp(14px, min(1.05vw, 2.25vh), 17px); line-height: 1.7; color: var(--fg); opacity: .9; white-space: pre-line; }
.prompt-text .ph { color: var(--accent); }

/* ---------- 01 Cover ---------- */
.cover .cover-bg { position: absolute; inset: -30px; z-index: -1; overflow: hidden; }
.cover .cover-bg img { width: 100%; height: 100%; object-fit: cover; filter: grayscale(1) brightness(.35) blur(2px); transform: translate3d(calc(var(--tx, 0) * -10px), calc(var(--ty, 0) * -10px), 0) scale(1.06); transition: transform 1.2s var(--ease); }
.cover .cover-bg::after { content: ''; position: absolute; inset: 0; background: linear-gradient(90deg, var(--ink) 18%, rgba(15,15,15,.82) 55%, rgba(15,15,15,.55)); }
.cover-logo { display: block; width: clamp(170px, 15vw, 270px); height: auto; margin-bottom: clamp(18px, 4vh, 44px); }
.cover h1 { margin: clamp(12px, 2.4vh, 24px) 0 clamp(14px, 2.8vh, 28px); }
.cover h1 .dot { color: var(--accent); }
.cover .lead { max-width: 44ch; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: clamp(18px, 4vh, 40px); }
.cover-meta { display: flex; flex-wrap: wrap; gap: 8px 28px; margin-top: clamp(18px, 3.6vh, 36px); font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: #8f8f8f; }
.cover-meta span { display: inline-flex; align-items: center; gap: 10px; }
.cover-meta b { font-weight: 600; color: #f2f1ed; font-size: 13px; }
.cover-visual { position: relative; transform: perspective(1400px) rotateY(calc(var(--tx, 0) * -3deg)) rotateX(calc(var(--ty, 0) * 3deg)); transition: transform 1.2s var(--ease); }
.cover-visual::before { content: ''; position: absolute; inset: 18px -18px -18px 18px; border: 1px solid rgba(255,255,255,.12); z-index: -1; }
.cover-visual button { display: block; width: 100%; overflow: hidden; cursor: zoom-in; }
.cover-visual img { display: block; width: 100%; height: clamp(260px, calc(100dvh - var(--header) - var(--footer) - 150px), 680px); object-fit: cover; transition: transform 1.4s var(--ease); }
.cover-visual button:hover img { transform: scale(1.03); }
.cover-visual figcaption { display: flex; justify-content: space-between; margin-top: 14px; font-size: 11px; letter-spacing: .14em; text-transform: uppercase; color: #8f8f8f; }

/* ---------- 03 Library ---------- */
.library { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(14px, 1.6vw, 24px); }
.card-top { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: clamp(12px, 2vh, 18px); }
.count { font-family: var(--font-head); font-size: 13px; color: var(--accent); }
.chips { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.chips button { padding: 8px 13px; font-size: 13px; border: 1px solid var(--line-strong); transition: background .3s, color .3s, border-color .3s; }
.chips button:hover { background: var(--fg); color: var(--bg); border-color: var(--fg); }
.strip { display: grid; grid-template-columns: repeat(var(--n, 4), minmax(0, 1fr)); gap: 10px; margin-top: clamp(14px, 2.6vh, 26px); }
.strip-item { position: relative; overflow: hidden; background: var(--surface-2); cursor: zoom-in; }
.strip-item img { display: block; width: 100%; height: clamp(90px, 19vh, 240px); object-fit: cover; transition: transform 1.2s var(--ease); }
.strip-item:hover img { transform: scale(1.04); }
.strip-item span { position: absolute; left: 10px; bottom: 10px; padding: 4px 8px; font-size: 11px; letter-spacing: .06em; background: rgba(15,15,15,.72); color: #eee; }

/* ---------- 04 Anatomy ---------- */
.anatomy { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: clamp(12px, 1.4vw, 22px); }
.anatomy-item { display: flex; flex-direction: column; justify-content: flex-start; text-align: left; padding-top: clamp(12px, 2vh, 20px); border-top: 1px solid var(--line-strong); transition: border-color .4s; }
.anatomy-item strong { display: block; font-family: var(--font-head); font-weight: 400; font-size: clamp(30px, min(3vw, 5.6vh), 56px); line-height: 1; margin-bottom: clamp(6px, 1.4vh, 16px); color: var(--muted); transition: color .4s; }
.anatomy-item p { margin-top: 8px; font-size: clamp(13px, min(.98vw, 2vh), 15px); line-height: 1.55; color: var(--muted); }
.anatomy-item.on { border-top-color: var(--accent); }
.anatomy-item.on strong { color: var(--accent); }
.anatomy-example { margin-top: clamp(16px, 3.2vh, 34px); padding: clamp(14px, 2.4vh, 24px); background: var(--surface); border: 1px solid var(--line); }
.anatomy-example p { margin-top: 10px; font-size: clamp(14px, min(1.1vw, 2.3vh), 18px); line-height: 1.75; }
.anatomy-example mark { background: transparent; color: var(--muted); padding: 2px 0; transition: background .45s, color .45s, box-shadow .45s; }
.anatomy-example mark.on { background: var(--accent-soft); color: var(--fg); box-shadow: inset 0 -2px 0 var(--accent); }

/* ---------- 05 Golden rule ---------- */
.golden { font-family: var(--font-head); font-size: clamp(18px, min(1.65vw, 3.3vh), 30px); line-height: 1.5; letter-spacing: -.02em; max-width: 64ch; color: var(--fg); }
.golden em { font-style: normal; color: var(--accent); }
.golden-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: clamp(16px, 3vh, 30px); }
.usage { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(12px, 1.4vw, 20px); margin-top: clamp(16px, 3.2vh, 34px); }
.usage .card { display: grid; grid-template-columns: 30px 1fr; gap: 14px; align-items: start; }
.usage .card p { font-size: clamp(14px, 1.05vw, 16px); line-height: 1.55; }
.badge { width: 30px; height: 30px; display: grid; place-items: center; border: 1px solid var(--line-strong); }
.badge svg { width: 15px; height: 15px; stroke-width: 2; }
.yes .badge { color: var(--accent); border-color: var(--accent); }

/* ---------- 06 / 22 Stepper & timeline ---------- */
.stepper { --cols: 5; position: relative; list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(var(--cols), minmax(0, 1fr)); gap: clamp(12px, 1.6vw, 26px); }
.stepper.cols-4 { --cols: 4; }
.stepper-line { position: absolute; left: 0; right: 0; top: 34px; height: 1px; background: var(--line-strong); pointer-events: none; }
.stepper-line i { display: block; height: 100%; width: calc((var(--step, 0) + .5) * 100% / var(--cols)); background: var(--accent); transition: width .8s var(--ease); }
.stepper button { display: flex; flex-direction: column; justify-content: flex-start; width: 100%; height: 100%; text-align: left; }
.step-no { display: block; height: 24px; font-size: 12px; letter-spacing: .1em; color: var(--muted); font-variant-numeric: tabular-nums; }
.step-dot { display: block; width: 9px; height: 9px; margin: 6px 0 clamp(12px, 2.4vh, 22px); border-radius: 50%; background: var(--bg); border: 1px solid var(--line-strong); transition: background .4s, border-color .4s, transform .5s var(--ease); }
.stepper li.done .step-dot { background: var(--accent); border-color: var(--accent); }
.stepper li.on .step-dot { transform: scale(1.6); }
.stepper h3, .stepper p { transition: opacity .45s; }
.stepper li:not(.done) h3, .stepper li:not(.done) p { opacity: .45; }
.stepper button:hover h3, .stepper button:hover p { opacity: 1; }
.stepper p { margin-top: 8px; font-size: clamp(13px, min(1vw, 2.1vh), 16px); line-height: 1.55; color: var(--muted); }
.stepper.cols-4 h3 { font-size: clamp(22px, min(2vw, 4vh), 32px); font-weight: 400; letter-spacing: -.03em; }
.outputs { margin-top: clamp(18px, 3.6vh, 38px); }
.outputs .strip { margin-top: 10px; }
.outputs .strip-item img { height: clamp(80px, 16vh, 200px); }

/* ---------- 09 Decision guide ---------- */
.guide { display: grid; grid-template-columns: minmax(0, .78fr) minmax(0, 1.22fr); gap: clamp(20px, 3.4vw, 60px); align-items: stretch; }
.guide-list { display: flex; flex-direction: column; }
.guide-list .label { margin-bottom: 10px; }
.guide-list button { position: relative; display: grid; grid-template-columns: 34px 1fr; align-items: center; text-align: left; padding: clamp(10px, 1.9vh, 16px) 0; border-bottom: 1px solid var(--line); font-size: clamp(14px, min(1.1vw, 2.3vh), 18px); color: var(--muted); transition: color .3s, padding .45s var(--ease); }
.guide-list button span { font-size: 11px; color: var(--muted); }
.guide-list button::before { content: ''; position: absolute; left: -1px; top: 20%; bottom: 20%; width: 2px; background: var(--accent); transform: scaleY(0); transition: transform .45s var(--ease); }
.guide-list button:hover { color: var(--fg); }
.guide-list button[aria-selected="true"] { color: var(--fg); padding-left: 16px; }
.guide-list button[aria-selected="true"]::before { transform: scaleY(1); }
.guide-list button[aria-selected="true"] span { color: var(--accent); }
.guide-result { display: grid; }
.guide-card { grid-area: 1 / 1; min-width: 0; display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr); background: var(--surface); border: 1px solid var(--line); transition: opacity .5s var(--ease), transform .6s var(--ease), visibility .5s; }
.guide-card:not(.on) { opacity: 0; visibility: hidden; transform: translateY(10px); }
.guide-card .media-main img { height: 100%; min-height: clamp(220px, 44vh, 460px); }
.guide-info { padding: clamp(18px, 3vh, 34px); display: flex; flex-direction: column; gap: 6px; }
.guide-info h3 { font-size: clamp(20px, min(1.8vw, 3.6vh), 30px); font-weight: 500; letter-spacing: -.03em; margin-bottom: clamp(10px, 2.4vh, 24px); }
.guide-info p { font-size: 15px; line-height: 1.55; margin-bottom: auto; padding-bottom: 18px; }
.guide-info .btn { align-self: flex-start; }

/* ---------- 14 Compare ---------- */
.compare { --pos: 50%; position: relative; overflow: hidden; user-select: none; -webkit-user-select: none; touch-action: pan-y; background: var(--surface-2); }
.compare img { display: block; width: 100%; height: var(--media-h); object-fit: cover; pointer-events: none; }
.compare-top { position: absolute; inset: 0; clip-path: inset(0 0 0 var(--pos)); }
.compare-handle { position: absolute; top: 0; bottom: 0; left: var(--pos); width: 2px; margin-left: -1px; background: #fff; pointer-events: none; box-shadow: 0 0 20px rgba(0,0,0,.25); }
.compare-handle i { position: absolute; top: 50%; left: 50%; width: 46px; height: 46px; border-radius: 50%; background: #fff; transform: translate(-50%, -50%); box-shadow: 0 8px 30px rgba(0,0,0,.35); transition: transform .4s var(--ease); }
.compare-handle i::before, .compare-handle i::after { content: ''; position: absolute; top: 15px; bottom: 15px; width: 1.5px; background: #111; }
.compare-handle i::before { left: 19px; }
.compare-handle i::after { right: 19px; }
.compare:hover .compare-handle i { transform: translate(-50%, -50%) scale(1.08); }
.compare input { position: absolute; inset: 0; width: 100%; height: 100%; margin: 0; opacity: 0; cursor: ew-resize; -webkit-appearance: none; appearance: none; }
.compare-label { position: absolute; top: 14px; padding: 6px 10px; font-size: 11px; letter-spacing: .14em; text-transform: uppercase; background: rgba(15,15,15,.7); color: #fff; backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); pointer-events: none; }
.compare-label.l { left: 14px; }
.compare-label.r { right: 14px; }
.compare:has(input:focus-visible) .compare-handle i { outline: 2px solid var(--accent); outline-offset: 3px; }

/* ---------- 18 QC checklist ---------- */
.qc { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: clamp(10px, 1.2vw, 16px); }
.qc-item { position: relative; display: block; cursor: pointer; padding: clamp(14px, 2.2vh, 20px) clamp(14px, 1.2vw, 20px) clamp(14px, 2.2vh, 20px) 52px; background: var(--surface); border: 1px solid var(--line); transition: border-color .35s, transform .45s var(--ease); }
.qc-item:hover { border-color: var(--line-strong); transform: translateY(-2px); }
.qc-item input, .check input { position: absolute; opacity: 0; pointer-events: none; }
.qc-box { position: absolute; left: 18px; top: clamp(16px, 2.4vh, 22px); width: 20px; height: 20px; border: 1.5px solid var(--line-strong); display: grid; place-items: center; transition: background .3s, border-color .3s; }
.qc-box svg { width: 13px; height: 13px; stroke-width: 2.6; color: #fff; opacity: 0; transform: scale(.4); transition: opacity .25s, transform .4s var(--ease); }
input:checked ~ .qc-box { background: var(--accent); border-color: var(--accent); }
input:checked ~ .qc-box svg { opacity: 1; transform: none; }
input:focus-visible ~ .qc-box { outline: 2px solid var(--accent); outline-offset: 3px; }
.qc-item:has(input:checked) { border-color: var(--accent); }
.qc-item p { margin-top: 6px; font-size: clamp(13px, min(.95vw, 2vh), 15px); line-height: 1.5; color: var(--muted); }
.qc-status { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 22px; margin-top: clamp(14px, 2.8vh, 28px); }
.meter { flex: 1 1 200px; height: 3px; background: var(--line); overflow: hidden; }
.meter i { display: block; height: 100%; width: 100%; background: var(--accent); transform: scaleX(0); transform-origin: left; transition: transform .6s var(--ease); }
.qc-score { font-family: var(--font-head); font-weight: 600; font-size: 15px; font-variant-numeric: tabular-nums; }
.qc-verdict { font-size: 14px; color: var(--muted); }
.qc-status.passed .qc-verdict { color: var(--fg); font-weight: 600; }

/* ---------- 19 Builder ---------- */
.builder-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: clamp(20px, 3.4vw, 60px); align-items: start; }
.builder { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(8px, 1.5vh, 14px) 14px; }
.field { display: flex; flex-direction: column; gap: 6px; min-width: 0; }
.field.wide { grid-column: 1 / -1; }
.field > span { font-size: 11px; font-weight: 600; letter-spacing: .14em; text-transform: uppercase; color: var(--muted); }
.field input, .field select, .practice textarea, .search input { width: 100%; padding: clamp(8px, 1.3vh, 11px) 12px; font-size: 14px; background: var(--surface); border: 1px solid var(--line-strong); border-radius: 0; color: var(--fg); transition: border-color .3s, background .3s; }
.field select { appearance: none; -webkit-appearance: none; background-image: linear-gradient(45deg, transparent 50%, currentColor 50%), linear-gradient(135deg, currentColor 50%, transparent 50%); background-position: calc(100% - 17px) 50%, calc(100% - 12px) 50%; background-size: 5px 5px; background-repeat: no-repeat; padding-right: 34px; }
.field select option { background: #1a1a1a; color: #eee; }
.field input:focus, .field select:focus, .practice textarea:focus, .search input:focus { outline: none; border-color: var(--accent); }
.field input::placeholder, .practice textarea::placeholder { color: var(--muted); opacity: .75; }
.builder-out .prompt-card { min-height: clamp(200px, 34vh, 360px); }

/* ---------- 20 / 21 Exercises ---------- */
.scenario { margin-bottom: clamp(14px, 2.8vh, 28px); }
.scenario p { margin-top: 10px; font-family: var(--font-head); font-size: clamp(20px, min(2vw, 4vh), 34px); line-height: 1.35; letter-spacing: -.03em; max-width: 30ch; }
.task-label { display: block; margin-bottom: 10px; }
.practice { background: var(--surface); border: 1px solid var(--line); padding: clamp(16px, 2.6vh, 26px); }
.practice-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; }
.practice-score { font-family: var(--font-head); font-weight: 600; font-variant-numeric: tabular-nums; }
.practice textarea { display: block; resize: vertical; min-height: clamp(96px, 18vh, 180px); line-height: 1.6; }
.practice .meter { margin: 12px 0 4px; }
.checks { list-style: none; margin: 10px 0 0; padding: 0; display: grid; gap: clamp(4px, .9vh, 8px); }
.checks li { display: flex; align-items: center; gap: 10px; font-size: 14px; color: var(--muted); transition: color .3s; }
.checks li i { width: 16px; height: 16px; flex: none; border: 1.5px solid var(--line-strong); border-radius: 50%; display: grid; place-items: center; transition: background .3s, border-color .3s; }
.checks li i svg { width: 10px; height: 10px; stroke-width: 3; color: #fff; opacity: 0; transition: opacity .25s; }
.checks li.ok { color: var(--fg); }
.checks li.ok i { background: var(--accent); border-color: var(--accent); }
.checks li.ok i svg { opacity: 1; }
.practice-foot { display: flex; flex-wrap: wrap; gap: 10px; margin-top: clamp(12px, 2.2vh, 20px); }
.trainer { margin-top: 12px; font-size: 14px; line-height: 1.65; color: var(--muted); border-left: 2px solid var(--accent); padding-left: 14px; }

.deliv-top { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: 8px; }
.check { position: relative; display: grid; grid-template-columns: 22px 1fr; gap: 14px; align-items: center; padding: clamp(9px, 1.6vh, 13px) 0; border-bottom: 1px solid var(--line); cursor: pointer; font-size: clamp(14px, min(1.04vw, 2.2vh), 17px); line-height: 1.5; }
.check:first-of-type { border-top: 1px solid var(--line); }
.check .qc-box { position: relative; left: auto; top: auto; }
.check span:last-child { transition: opacity .3s; }
.check input:checked ~ span:last-child { opacity: .5; text-decoration: line-through; text-decoration-thickness: 1px; }

/* ---------- 22 Closing ---------- */
.closing { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 20px 40px; align-items: end; margin-top: clamp(20px, 4.2vh, 46px); padding-top: clamp(18px, 3.4vh, 34px); border-top: 1px solid var(--line); }
.ending { font-family: var(--font-head); font-size: clamp(22px, min(2.2vw, 4.4vh), 38px); line-height: 1.25; letter-spacing: -.035em; max-width: 26ch; }
.closing .note { margin-top: 14px; }
.closing-side { display: flex; flex-direction: column; align-items: flex-end; gap: 18px; }
.closing-logo { width: clamp(120px, 10vw, 170px); height: auto; opacity: .9; }

/* ---------- Contents drawer ---------- */
dialog { color: #f2f1ed; }
dialog::backdrop { background: rgba(0,0,0,.6); backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); }
.drawer { position: fixed; inset: 0 0 0 auto; margin: 0; width: min(520px, 100vw); height: 100dvh; max-height: none; max-width: 100vw; padding: calc(22px + env(safe-area-inset-top, 0px)) 30px 30px; background: #141414; border: 0; border-left: 1px solid rgba(255,255,255,.1); overflow-y: auto; }
.drawer[open] { animation: drawer-in .55s var(--ease); }
@keyframes drawer-in { from { transform: translateX(40px); opacity: 0; } }
.drawer-top { display: flex; justify-content: space-between; align-items: center; }
.drawer h2 { font-size: 34px; margin: 18px 0 20px; }
.search { position: relative; display: block; margin-bottom: 8px; --fg: #f2f1ed; --surface: rgba(255,255,255,.04); --line-strong: rgba(255,255,255,.2); }
.search svg { position: absolute; left: 12px; top: 50%; transform: translateY(-50%); width: 17px; height: 17px; color: #8a8a8a; }
.search input { padding-left: 38px; }
.toc-group { margin-top: 18px; }
.toc-group > .label { display: block; margin-bottom: 6px; color: var(--accent); }
#index-nav a { display: grid; grid-template-columns: 34px 1fr; gap: 6px; padding: 11px 8px; margin: 0 -8px; font-size: 14px; line-height: 1.4; color: #cfcfcf; border-bottom: 1px solid rgba(255,255,255,.07); transition: background .25s, color .25s; }
#index-nav a span { font-size: 11px; color: #777; padding-top: 3px; font-variant-numeric: tabular-nums; }
#index-nav a:hover { background: rgba(255,255,255,.05); color: #fff; }
#index-nav a[aria-current] { color: #fff; background: rgba(176,145,106,.14); }
#index-nav a[aria-current] span { color: var(--accent); }
.drawer-empty { color: #888; font-size: 14px; margin-top: 20px; }

/* ---------- Lightbox ---------- */
.lightbox { width: 100vw; height: 100dvh; max-width: none; max-height: none; margin: 0; padding: 0; border: 0; background: rgba(10,10,10,.97); overflow: hidden; }
.lightbox[open] { display: grid; grid-template-rows: auto minmax(0, 1fr) auto; animation: fade-in .35s ease; }
.lightbox::backdrop { background: transparent; backdrop-filter: none; -webkit-backdrop-filter: none; }
@keyframes fade-in { from { opacity: 0; } }
.lb-top { display: flex; align-items: center; gap: 20px; padding: calc(14px + env(safe-area-inset-top, 0px)) 22px 14px 28px; }
.lb-top p { flex: 1; font-size: 14px; color: #cfcfcf; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.lb-stage { --lb-pad: clamp(16px, 6vw, 96px); position: relative; overflow: hidden; touch-action: pan-y; }
.lb-stage img { position: absolute; top: 0; bottom: 0; left: var(--lb-pad); width: calc(100% - 2 * var(--lb-pad)); height: 100%; object-fit: contain; cursor: zoom-in; transition: transform .55s var(--ease), opacity .3s ease; user-select: none; -webkit-user-drag: none; }
.lb-stage img.loading { opacity: 0; }
.lb-stage.zoomed img { transform: scale(2.2); cursor: zoom-out; }
.lb-nav { position: absolute; top: 50%; transform: translateY(-50%); width: 52px; height: 52px; background: rgba(255,255,255,.06); color: #fff; }
.lb-nav:hover:not(:disabled) { background: rgba(255,255,255,.14); }
.lb-nav svg { width: 22px; height: 22px; }
.lb-prev { left: 18px; }
.lb-next { right: 18px; }
.lb-bottom { display: grid; justify-items: center; gap: 10px; padding: 14px 20px calc(16px + env(safe-area-inset-bottom, 0px)); }
.lb-thumbs { display: flex; gap: 8px; max-width: 100%; overflow-x: auto; scrollbar-width: none; }
.lb-thumbs button { flex: none; width: 72px; height: 48px; overflow: hidden; opacity: .45; transition: opacity .3s; position: relative; }
.lb-thumbs button::after { content: ''; position: absolute; inset: 0; box-shadow: inset 0 0 0 1px transparent; transition: box-shadow .3s; }
.lb-thumbs button[aria-current], .lb-thumbs button:hover { opacity: 1; }
.lb-thumbs button[aria-current]::after { box-shadow: inset 0 0 0 2px var(--accent); }
.lb-thumbs img { width: 100%; height: 100%; object-fit: cover; display: block; }
.lb-hint { font-size: 12px; color: #7a7a7a; }

/* ---------- Responsive ---------- */
@media (max-width: 1240px) {
  .chapters { display: none; }
}
@media (max-width: 1100px) and (min-width: 901px) {
  .qc { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .anatomy-item p { display: none; }
}
@media (min-width: 901px) and (max-height: 760px) {
  :root { --header: 64px; --footer: 56px; }
  .wordmark img { height: 36px; }
  .note { margin-top: 12px; }
  .qc-item p { font-size: 13px; line-height: 1.45; }
}
@media (max-width: 900px) {
  :root { --header: 64px; --footer: 60px; --media-h: clamp(220px, 58vw, 460px); }
  .wordmark img { height: 34px; }
  .menu-btn span { display: none; }
  .menu-btn { padding: 0 8px; }
  .dots, .kbd-hint, .footer-title { display: none; }
  .bottom-bar { grid-template-columns: 1fr; justify-items: center; }
  .slide { align-items: flex-start; padding-top: calc(var(--header) + 40px); padding-bottom: calc(var(--footer) + 48px); }
  .split, .guide, .builder-grid, .library, .usage { grid-template-columns: minmax(0, 1fr); }
  .split { gap: 28px; }
  h2 { font-size: clamp(28px, 7.4vw, 42px); }
  .lead { font-size: 16px; }
  .points li p { font-size: 15px; }
  .cover-visual img { height: 62vw; }
  .cover-visual::before { display: none; }
  .anatomy { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
  .anatomy-item strong { font-size: 40px; }
  .stepper, .stepper.cols-4 { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .stepper-line { display: none; }
  .stepper li { position: relative; border-left: 1px solid var(--line-strong); padding: 0 0 18px 20px; }
  .stepper li.done { border-left-color: var(--accent); }
  .step-dot { position: absolute; left: -5px; top: 4px; margin: 0; }
  .step-no { height: auto; margin-bottom: 4px; }
  .stepper li:not(.done) h3, .stepper li:not(.done) p { opacity: 1; }
  .strip, .outputs .strip { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .strip-item img, .outputs .strip-item img { height: 30vw; }
  .guide-card { grid-template-columns: minmax(0, 1fr); }
  .guide-card .media-main img { min-height: 0; height: 52vw; }
  .qc { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .closing { grid-template-columns: minmax(0, 1fr); }
  .closing-side { align-items: flex-start; }
  .lb-nav { top: auto; bottom: 86px; transform: none; width: 44px; height: 44px; }
  .lb-hint { display: none; }
  .drawer { padding-left: 22px; padding-right: 22px; }
}
@media (max-width: 520px) {
  .anatomy, .qc, .builder { grid-template-columns: minmax(0, 1fr); }
  .field.wide { grid-column: auto; }
  .cta .btn, .cta .btn-ghost { flex: 1 1 auto; justify-content: center; }
  .media-thumbs img { height: 52px; }
  .tabs { gap: 18px; }
  #fullscreen { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001ms !important; transition-duration: .001ms !important; transition-delay: 0s !important; }
  .cover-visual, .cover .cover-bg img { transform: none; }
}