:root {
  --canvas: #f5f7fa;
  --surface: #ffffff;
  --soft: #eef4ff;
  --muted-surface: #edf1f6;
  --ink: #142238;
  --text: #435166;
  --muted: #6a798e;
  --line: #d7e0eb;
  --navy: #12356b;
  --blue: #2b70ef;
  --blue-dark: #1c48b2;
  --green: #187451;
  --red: #a82b21;
  --warning: #fff7e6;
  --focus: #efb849;
  --header-height: 64px;
  --toolbar-height: 72px;
  --slide-padding: clamp(1rem, 3.5vw, 3rem);
  --content-gap: clamp(.65rem, 1.6vw, 1.35rem);
  --title-size: clamp(2.2rem, 5vw, 4.8rem);
  --h2-size: clamp(1.3rem, 2.5vw, 2.2rem);
  --body-size: clamp(.78rem, 1.25vw, 1rem);
  --small-size: clamp(.65rem, .9vw, .78rem);
  --max: 1180px;
}

* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; overflow-x: hidden; }
html { scroll-behavior: smooth; scroll-snap-type: y mandatory; }
body { margin: 0; background: var(--canvas); color: var(--ink); font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", "Noto Sans JP", sans-serif; font-size: 16px; line-height: 1.55; }
body.challenge-active { overflow: hidden; }
button { font: inherit; cursor: pointer; }
[hidden] { display: none !important; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; }

.slide { width: 100vw; height: 100vh; height: 100dvh; overflow: hidden; scroll-snap-align: start; display: flex; flex-direction: column; position: relative; }
.slide-content { flex: 1; min-height: 0; display: grid; grid-template-rows: auto minmax(0, 1fr) auto; gap: var(--content-gap); max-height: 100%; overflow: hidden; padding: var(--slide-padding); }

.skip-link { position: fixed; z-index: 100; top: 7px; left: 7px; transform: translateY(-150%); border-radius: 7px; background: #fff; padding: 8px 12px; color: var(--ink); }
.skip-link:focus { transform: translateY(0); }
.topbar { position: fixed; z-index: 30; top: 0; left: 0; width: 100%; height: var(--header-height); display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); background: rgba(255,255,255,.96); padding: 0 clamp(16px,4vw,44px); backdrop-filter: blur(10px); }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); line-height: 1.08; text-decoration: none; }
.brand-mark { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 8px; background: var(--navy); color: #fff; font-size: .78rem; font-weight: 800; }
.brand strong, .brand small { display: block; }
.brand strong { font-size: .78rem; letter-spacing: .06em; }
.brand small { margin-top: 3px; color: var(--muted); font-size: .6rem; letter-spacing: .07em; }
.topbar-link { border-bottom: 2px solid var(--blue); padding: 6px 0 4px; color: var(--blue-dark); font-size: var(--small-size); font-weight: 800; text-decoration: none; }
.topbar-link:hover { color: var(--navy); }
body.challenge-active .topbar { display: none; }

.primary-button, .secondary-button { min-height: 42px; display: inline-flex; align-items: center; justify-content: center; border-radius: 7px; padding: 0 18px; font-weight: 750; line-height: 1; text-decoration: none; transition: background-color 150ms ease, transform 120ms ease; }
.primary-button { border: 1px solid var(--blue); background: var(--blue); color: #fff; }
.primary-button:hover { border-color: var(--blue-dark); background: var(--blue-dark); }
.secondary-button { border: 1px solid var(--line); background: #fff; color: var(--text); }
.secondary-button:hover { background: var(--muted-surface); }
.primary-button:active, .secondary-button:active { transform: translateY(1px); }
.secondary-button:disabled { cursor: not-allowed; opacity: .38; }

/* 表紙と課題選択も1画面ずつ表示 */
.home-slide { padding-top: var(--header-height); }
.hero { justify-content: center; }
.hero-copy { width: min(86vw, 900px); margin: 0 auto; }
.hero-label, .level-label { margin: 0 0 clamp(.4rem,1vh,.8rem); color: var(--blue-dark); font-size: var(--small-size); font-weight: 800; letter-spacing: .04em; }
.hero h1 { max-width: 850px; margin: 0; font-size: clamp(2.8rem,7vw,6.4rem); line-height: 1.02; letter-spacing: -.055em; text-wrap: balance; }
.hero-copy > p:not(.hero-label) { max-width: 34rem; margin: clamp(.8rem,2vh,1.4rem) 0 clamp(1rem,3vh,1.8rem); color: var(--text); font-size: clamp(.86rem,1.5vw,1.15rem); }

.challenge-section { justify-content: center; padding-right: var(--slide-padding); padding-left: var(--slide-padding); }
.challenge-slide-content { width: min(92vw, var(--max)); max-height: calc(100dvh - var(--header-height)); margin: 0 auto; overflow: hidden; }
.section-title { margin-bottom: clamp(.7rem,2vh,1.5rem); }
.section-title h2 { margin: 0; font-size: clamp(2rem,4.5vw,4rem); line-height: 1.08; letter-spacing: -.045em; }
.section-title p { margin: .45rem 0 0; color: var(--text); font-size: var(--body-size); }
.challenge-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.challenge-card + .challenge-card { border-left: 1px solid var(--line); }
.challenge-card-body { height: clamp(230px, 34vh, 330px); display: flex; flex-direction: column; align-items: flex-start; padding: clamp(1rem,2.5vw,2rem); }
.challenge-card h3 { margin: 0; font-size: clamp(1.3rem,2.3vw,2.15rem); line-height: 1.15; letter-spacing: -.03em; text-wrap: balance; }
.challenge-card-body > p:not(.level-label) { margin: .65rem 0 1rem; color: var(--text); font-size: var(--body-size); }
.challenge-card .primary-button { width: 100%; margin-top: auto; }

/* 全員共通の次回課題 */
.homework-section { justify-content: center; padding-right: var(--slide-padding); padding-left: var(--slide-padding); background: #eef3f8; }
.homework-slide-content { width: min(92vw, var(--max)); max-height: calc(100dvh - var(--header-height)); display: grid; grid-template-rows: auto minmax(0,1fr) auto; gap: clamp(.7rem,2vh,1.25rem); margin: 0 auto; overflow: hidden; }
.homework-heading { display: grid; grid-template-columns: minmax(300px,1.1fr) minmax(280px,.9fr); align-items: end; gap: clamp(1rem,4vw,3rem); }
.homework-heading .hero-label { grid-column: 1 / -1; margin-bottom: -.25rem; }
.homework-heading h2 { margin: 0; font-size: clamp(2rem,4.7vw,4.4rem); line-height: 1.02; letter-spacing: -.05em; text-wrap: balance; }
.homework-heading > p:last-child { margin: 0 0 .25rem; color: var(--text); font-size: var(--body-size); }
.homework-grid { min-height: 0; display: grid; grid-template-columns: minmax(400px,1.2fr) minmax(300px,.8fr); border: 1px solid var(--line); border-radius: 12px; background: var(--surface); overflow: hidden; }
.weekly-card, .assignment-example { min-width: 0; padding: clamp(.8rem,2.2vw,1.7rem); overflow: hidden; }
.weekly-card { display: flex; flex-direction: column; }
.assignment-example { display: grid; grid-template-rows: auto minmax(0,1fr); gap: clamp(.55rem,1.3vh,.85rem); border-left: 1px solid var(--line); background: var(--navy); color: #fff; }
.card-kicker { margin: 0 0 .25rem; color: var(--blue-dark); font-size: var(--small-size); font-weight: 800; letter-spacing: .04em; }
.weekly-card h3, .assignment-example h3 { margin: 0; font-size: clamp(1.2rem,2.2vw,1.9rem); line-height: 1.15; letter-spacing: -.025em; }
.homework-steps { list-style: none; display: grid; margin: auto 0 0; border-top: 1px solid var(--line); padding: 0; }
.homework-steps li { display: grid; grid-template-columns: 32px 1fr; align-items: center; gap: .65rem; border-bottom: 1px solid var(--line); padding: clamp(.45rem,1.2vh,.75rem) 0; }
.homework-steps span { color: var(--blue); font-size: clamp(1.1rem,2vw,1.5rem); font-weight: 800; }
.homework-steps p { margin: 0; color: var(--text); font-size: var(--body-size); font-weight: 650; }
.assignment-example .card-kicker { color: #9fc2ff; }
.assignment-example > div > p:last-child { max-width: 37rem; margin: .5rem 0 0; color: #dce7f8; font-size: var(--body-size); }
.example-flow { list-style: none; align-self: stretch; display: grid; grid-template-columns: repeat(2,1fr); margin: 0; border: 1px solid rgba(255,255,255,.22); padding: 0; }
.example-flow li { position: relative; display: grid; align-content: center; gap: .15rem; min-height: clamp(60px,10vh,90px); padding: .5rem .65rem; color: #fff; font-size: var(--small-size); font-weight: 750; }
.example-flow li:nth-child(even) { border-left: 1px solid rgba(255,255,255,.22); }
.example-flow li:nth-child(n+3) { border-top: 1px solid rgba(255,255,255,.22); }
.example-flow span { color: #8bb7ff; font-size: .65rem; letter-spacing: .08em; }
.homework-footer { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.homework-footer p { margin: 0; color: var(--text); font-size: var(--small-size); }

/* 課題内の固定ナビ */
.challenge-toolbar { position: fixed; z-index: 30; top: 0; left: 0; width: 100%; height: var(--toolbar-height); border-bottom: 1px solid var(--line); background: rgba(245,247,250,.97); backdrop-filter: blur(10px); }
.challenge-toolbar-inner { width: min(100%, var(--max)); height: 100%; display: grid; grid-template-columns: 160px 1fr; align-items: center; gap: clamp(.6rem,2vw,1.5rem); margin: 0 auto; padding: 0 var(--slide-padding); }
.back-button { min-height: 38px; border: 0; border-radius: 7px; background: transparent; padding: 0 8px; color: var(--text); font-size: var(--small-size); font-weight: 700; text-align: left; }
.back-button:hover { background: var(--muted-surface); }
.stepper { display: grid; grid-template-columns: repeat(3,1fr); gap: 6px; }
.stepper button { min-height: 40px; border: 1px solid var(--line); border-radius: 7px; background: #fff; padding: 5px 7px; color: var(--muted); font-size: var(--small-size); font-weight: 750; }
.stepper button.current { border-color: var(--blue); background: var(--blue); color: #fff; }

.challenge-slide { padding-top: var(--toolbar-height); background: var(--canvas); }
.challenge-slide-inner { flex: 1; min-height: 0; width: min(100%, var(--max)); margin: 0 auto; overflow: hidden; }
.slide-heading { min-height: 0; }
.slide-heading > p { margin: 0 0 .3rem; color: var(--blue-dark); font-size: var(--small-size); font-weight: 800; }
.slide-heading h1 { margin: 0; font-size: var(--h2-size); line-height: 1.08; letter-spacing: -.04em; text-wrap: balance; }

/* Slide 1: 課題名＋完成例 */
.goal-slide { grid-template-rows: minmax(0,1fr) auto; }
.goal-grid { min-height: 0; display: grid; grid-template-columns: minmax(0,.9fr) minmax(300px,1.1fr); align-items: center; gap: clamp(1rem,4vw,3.5rem); }
.goal-copy h1 { margin: 0; font-size: var(--title-size); line-height: 1.03; letter-spacing: -.05em; text-wrap: balance; }
.goal-copy > p:last-child { max-width: 32rem; margin: clamp(.5rem,1.5vh,1rem) 0 0; color: var(--text); font-size: var(--body-size); }
.preview-panel { min-width: 0; }
.preview-panel h2 { margin: 0 0 .5rem; font-size: clamp(1rem,1.8vw,1.4rem); }
.preview-panel > small { display: block; margin-top: .45rem; color: var(--muted); font-size: var(--small-size); }

/* Slide 2: 条件 */
.rules-grid { min-height: 0; display: grid; grid-template-columns: 1fr 1fr; align-items: stretch; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.rules-grid > div { display: flex; flex-direction: column; justify-content: center; padding: clamp(1rem,3vw,2.4rem); }
.rules-grid > div + div { border-left: 1px solid var(--line); }
.rules-grid h2 { margin: 0 0 clamp(.5rem,1.5vh,1rem); font-size: var(--h2-size); }
.rules-grid ul { margin: 0; padding-left: 1.2rem; color: var(--text); }
.rules-grid li { font-size: var(--body-size); }
.rules-grid li + li { margin-top: clamp(.35rem,1vh,.75rem); }

/* Slide 3: Codexの3手順 */
.big-steps { list-style: none; min-height: 0; display: grid; grid-template-columns: repeat(3,1fr); margin: 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); padding: 0; }
.big-steps li { display: grid; grid-template-rows: auto 1fr; gap: clamp(.4rem,1vh,.8rem); padding: clamp(1rem,3vw,2.2rem); }
.big-steps li + li { border-left: 1px solid var(--line); }
.big-steps span { color: var(--blue); font-size: clamp(2rem,5vw,4.5rem); font-weight: 800; line-height: .9; }
.big-steps p { margin: 0; color: var(--text); font-size: var(--body-size); font-weight: 650; }
.file-note { margin: 0; border-left: 3px solid var(--blue); padding-left: .7rem; color: var(--text); font-size: var(--small-size); }

/* Slide 4: テスト＋修正 */
.test-fix-grid { min-height: 0; display: grid; grid-template-columns: 1fr 1fr; gap: var(--content-gap); }
.test-fix-grid > section { min-width: 0; border: 1px solid var(--line); border-radius: 10px; background: #fff; padding: clamp(.8rem,2vw,1.6rem); overflow: hidden; }
.test-fix-grid h2 { margin: 0; font-size: clamp(1rem,1.8vw,1.35rem); }
.compact-list { list-style: none; display: grid; margin: .55rem 0 0; border-top: 1px solid var(--line); padding: 0; }
.compact-list li { display: grid; grid-template-columns: 28px 1fr; align-items: center; gap: .5rem; border-bottom: 1px solid var(--line); padding: clamp(.35rem,1vh,.7rem) 0; }
.compact-list span { color: var(--blue); font-size: var(--small-size); font-weight: 800; }
.compact-list p { margin: 0; color: var(--text); font-size: var(--body-size); }
.test-fix-grid small { display: block; margin-top: .6rem; border-left: 3px solid var(--blue); padding-left: .55rem; color: var(--text); font-size: var(--small-size); }

/* Slide 5: 公開終了 */
.publish-slide-body { min-height: 0; display: grid; grid-template-rows: auto 1fr; gap: var(--content-gap); }
.safety-block { display: grid; grid-template-columns: minmax(180px,.65fr) 1.35fr; align-items: center; gap: 1rem; border: 1px solid #e5c37d; border-radius: 9px; background: var(--warning); padding: clamp(.7rem,1.6vw,1.2rem); color: #65440e; }
.safety-block h2 { margin: 0; font-size: clamp(.95rem,1.6vw,1.25rem); }
.safety-block ul { display: grid; grid-template-columns: repeat(3,1fr); gap: .7rem; margin: 0; padding: 0; list-style: none; }
.safety-block li { font-size: var(--small-size); font-weight: 650; }
.publish-flow { list-style: none; min-height: 0; display: grid; grid-template-columns: repeat(3,1fr); margin: 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); padding: 0; }
.publish-flow li { display: grid; align-content: center; gap: .5rem; padding: clamp(.8rem,2.5vw,1.8rem); }
.publish-flow li + li { border-left: 1px solid var(--line); }
.publish-flow span { color: var(--blue); font-size: clamp(1.8rem,4vw,3.5rem); font-weight: 800; line-height: 1; }
.publish-flow p { margin: 0; color: var(--text); font-size: var(--body-size); font-weight: 650; }

/* 共通スライド下部 */
.page-actions { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: .8rem; }
.page-actions > span { color: var(--muted); font-size: var(--small-size); font-weight: 800; text-align: center; font-variant-numeric: tabular-nums; }
.page-actions .primary-button { min-width: 108px; }

/* 画像生成した完成画面例 */
.generated-preview { min-height: 0; display: grid; place-items: center; margin: 0; }
.generated-preview img { width: auto; height: auto; max-width: 100%; max-height: min(39vh, 340px); max-height: min(39dvh, 340px); display: block; aspect-ratio: auto; border: 1px solid var(--line); border-radius: 12px; background: #fff; object-fit: contain; object-position: center; box-shadow: 0 16px 36px rgba(18,53,107,.12); }

.reveal { opacity: 0; transform: translateY(18px); transition: opacity .36s ease, transform .36s ease; }
.challenge-slide.visible .reveal { opacity: 1; transform: translateY(0); }
.noscript { position: fixed; z-index: 100; inset: auto 0 0; margin: 0; background: var(--warning); padding: 12px; color: #65440e; text-align: center; }

@media (max-width: 700px) {
  :root { --toolbar-height: 84px; --slide-padding: clamp(.75rem,4vw,1.2rem); --title-size: clamp(1.8rem,8vw,3rem); --h2-size: clamp(1.25rem,5vw,2rem); --body-size: clamp(.7rem,2.8vw,.9rem); }
  .brand small { display: none; }
  .topbar-link { font-size: .68rem; }
  .challenge-grid { grid-template-columns: 1fr; }
  .challenge-card + .challenge-card { border-top: 1px solid var(--line); border-left: 0; }
  .challenge-card-body { height: auto; min-height: 0; display: grid; grid-template-columns: 1fr auto; align-items: center; gap: .2rem .8rem; padding: clamp(.7rem,2vh,1rem) 0; }
  .challenge-card-body .level-label, .challenge-card-body h3, .challenge-card-body > p { grid-column: 1; }
  .challenge-card-body > p:not(.level-label) { margin: .2rem 0; }
  .challenge-card .primary-button { grid-column: 2; grid-row: 1 / 4; width: auto; margin: 0; }
  .homework-heading { grid-template-columns: 1fr; gap: .4rem; }
  .homework-heading .hero-label { grid-column: 1; margin-bottom: 0; }
  .homework-heading h2 br { display: none; }
  .homework-grid { grid-template-columns: 1fr; }
  .weekly-card, .assignment-example { padding: .65rem .8rem; }
  .assignment-example { border-top: 1px solid var(--line); border-left: 0; }
  .weekly-card h3, .assignment-example h3 { font-size: clamp(1rem,4.3vw,1.4rem); }
  .homework-steps { margin-top: .4rem; }
  .homework-steps li { padding: .3rem 0; }
  .example-flow li { min-height: 48px; padding: .3rem; }
  .homework-footer p { max-width: 13rem; text-align: right; }
  .challenge-toolbar-inner { grid-template-columns: 1fr; gap: 4px; padding-top: 4px; padding-bottom: 6px; }
  .back-button { min-height: 26px; padding: 0 3px; }
  .stepper button { min-height: 38px; padding: 4px 2px; }
  .goal-grid { grid-template-columns: 1fr; align-content: center; gap: .7rem; }
  .goal-copy h1 { font-size: var(--title-size); }
  .preview-panel h2 { margin-bottom: .3rem; }
  .generated-preview img { max-height: min(29vh, 220px); }
  .rules-grid { grid-template-columns: 1fr; }
  .rules-grid > div { padding: .8rem 1rem; }
  .rules-grid > div + div { border-top: 1px solid var(--line); border-left: 0; }
  .rules-grid h2 { margin-bottom: .35rem; }
  .rules-grid li + li { margin-top: .25rem; }
  .big-steps { grid-template-columns: 1fr; }
  .big-steps li { grid-template-columns: 34px 1fr; grid-template-rows: auto; align-items: center; gap: .55rem; padding: .65rem .8rem; }
  .big-steps li + li { border-top: 1px solid var(--line); border-left: 0; }
  .big-steps span { font-size: 1.7rem; }
  .test-fix-grid { grid-template-columns: 1fr; gap: .6rem; }
  .test-fix-grid > section { padding: .7rem .8rem; }
  .compact-list { margin-top: .3rem; }
  .compact-list li { padding: .28rem 0; }
  .test-fix-grid small { margin-top: .3rem; }
  .safety-block { grid-template-columns: 1fr; gap: .4rem; }
  .safety-block ul { grid-template-columns: 1fr; gap: .2rem; }
  .publish-flow { grid-template-columns: 1fr; }
  .publish-flow li { grid-template-columns: 28px 1fr; align-items: center; gap: .5rem; padding: .45rem .7rem; }
  .publish-flow li + li { border-top: 1px solid var(--line); border-left: 0; }
  .publish-flow span { font-size: 1.5rem; }
  .publish-flow br { display: none; }
}

@media (max-height: 700px) {
  :root { --slide-padding: clamp(.65rem,2.5vw,1.5rem); --content-gap: clamp(.4rem,1.2vw,.8rem); --title-size: clamp(1.7rem,4.5vw,3.2rem); --h2-size: clamp(1.15rem,3vw,1.7rem); --body-size: clamp(.68rem,1.1vw,.86rem); }
  .primary-button, .secondary-button { min-height: 36px; }
  .challenge-card-body { height: clamp(190px,32vh,250px); }
  .slide-heading > p { margin-bottom: .15rem; }
  .generated-preview img { max-height: min(34vh, 220px); }
  .homework-heading h2 { font-size: clamp(1.7rem,4vw,3.2rem); }
  .weekly-card, .assignment-example { padding-top: .65rem; padding-bottom: .65rem; }
}

@media (max-height: 600px) {
  :root { --toolbar-height: 58px; --slide-padding: clamp(.45rem,2vw,1rem); --content-gap: .4rem; --title-size: clamp(1.45rem,4vw,2.4rem); --h2-size: clamp(1rem,2.6vw,1.4rem); --body-size: clamp(.64rem,1vw,.78rem); }
  .challenge-toolbar-inner { grid-template-columns: 120px 1fr; gap: .5rem; padding-top: 0; padding-bottom: 0; }
  .back-button { min-height: 34px; }
  .stepper button { min-height: 34px; }
  .generated-preview img { max-height: min(34vh, 190px); }
  .page-actions .primary-button, .page-actions .secondary-button { min-height: 32px; }
  .file-note { font-size: .62rem; }
  .homework-slide-content { gap: .45rem; }
  .homework-steps li { padding: .25rem 0; }
  .example-flow li { min-height: 46px; }
}

@media (max-width: 700px) and (max-height: 700px) {
  .challenge-card-body { height: auto; min-height: 0; }
}

@media (max-height: 500px) and (orientation: landscape) {
  :root { --toolbar-height: 50px; --title-size: clamp(1.25rem,3.5vw,2rem); --h2-size: clamp(.9rem,2.3vw,1.2rem); --body-size: clamp(.6rem,1vw,.72rem); --small-size: clamp(.56rem,.8vw,.66rem); }
  .home-slide { padding-top: 50px; }
  .topbar { --header-height: 50px; }
  .hero h1 { font-size: clamp(2rem,7vw,3.4rem); }
  .challenge-grid { grid-template-columns: repeat(3,1fr); }
  .challenge-card + .challenge-card { border-top: 0; border-left: 1px solid var(--line); }
  .challenge-card-body { height: 190px; display: flex; padding: .65rem; }
  .challenge-card .primary-button { width: 100%; margin-top: auto; }
  .homework-heading { grid-template-columns: 1fr 1fr; gap: .6rem; }
  .homework-heading .hero-label { grid-column: 1 / -1; }
  .homework-heading h2 { font-size: clamp(1.4rem,3.5vw,2.2rem); }
  .homework-grid { grid-template-columns: 1.2fr .8fr; }
  .weekly-card, .assignment-example { padding: .45rem .6rem; }
  .assignment-example { border-top: 0; border-left: 1px solid var(--line); }
  .assignment-example > div > p:last-child { margin-top: .2rem; }
  .homework-steps { margin-top: .2rem; }
  .homework-steps li { padding: .18rem 0; }
  .example-flow li { min-height: 38px; padding: .2rem .35rem; }
  .goal-grid { grid-template-columns: .9fr 1.1fr; }
  .rules-grid { grid-template-columns: 1fr 1fr; }
  .rules-grid > div + div { border-top: 0; border-left: 1px solid var(--line); }
  .big-steps { grid-template-columns: repeat(3,1fr); }
  .big-steps li { display: grid; grid-template-columns: 1fr; grid-template-rows: auto 1fr; padding: .45rem .6rem; }
  .big-steps li + li { border-top: 0; border-left: 1px solid var(--line); }
  .test-fix-grid { grid-template-columns: 1fr 1fr; }
  .publish-slide-body { grid-template-columns: .9fr 1.1fr; grid-template-rows: 1fr; }
  .safety-block { grid-template-columns: 1fr; }
  .publish-flow { grid-template-columns: repeat(3,1fr); }
  .publish-flow li { grid-template-columns: 1fr; }
  .publish-flow li + li { border-top: 0; border-left: 1px solid var(--line); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; }
  .reveal { transform: none; }
}

@media print {
  .topbar, .challenge-toolbar, .page-actions { display: none !important; }
  .slide { height: 100vh; break-after: page; }
}