:root {
  --blue: #1818dc;
  --ink: #17171c;
  --paper: #f4f2e9;
  --white: #fff;
  --acid: #ddff3f;
  --coral: #ff624d;
  --muted: #68686f;
  --line: #d6d2c6;
  --soft-blue: #ececff;
  font-family: Inter, Pretendard, "Apple SD Gothic Neo", "Noto Sans KR", Arial, sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; background: var(--paper); }
button, input, textarea, select { font: inherit; }
button { cursor: pointer; }
.hidden { display: none !important; }
.topbar { height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 12px clamp(18px, 3vw, 46px); border-top: 6px solid var(--blue); border-bottom: 1px solid var(--ink); background: rgba(244,242,233,.94); position: sticky; top: 0; z-index: 30; backdrop-filter: blur(12px); }
.brand { display: flex; align-items: center; gap: 12px; color: inherit; text-decoration: none; }
.brand-mark { width: 43px; height: 43px; display: grid; place-items: center; background: var(--blue); color: white; font-weight: 950; letter-spacing: -.08em; }
.brand b, .brand small { display: block; }
.brand b { font-size: 1rem; }
.brand small { margin-top: 2px; color: var(--muted); font: 750 .73rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace; }
.top-actions, .connection { display: flex; align-items: center; gap: 12px; }
.connection { font: 800 .76rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.connection i { width: 9px; height: 9px; border-radius: 50%; background: var(--coral); box-shadow: 0 0 0 4px rgba(255,98,77,.15); }
.text-button { border: 0; border-bottom: 1px solid currentColor; background: transparent; padding: 3px 0; color: var(--blue); font-weight: 850; }

main { max-width: 1600px; margin: 0 auto; }
.reader-shell { display: grid; grid-template-columns: 265px minmax(0, 1fr); align-items: start; }
.note-sidebar { position: sticky; top: 76px; height: calc(100vh - 76px); display: flex; flex-direction: column; border-right: 1px solid var(--ink); background: #ece9df; overflow-y: auto; }
.course-info { padding: 30px 24px 24px; border-bottom: 1px solid var(--ink); }
.course-info p, .kicker, .note-heading .kicker { margin: 0 0 12px; color: var(--blue); font: 900 .76rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: .08em; }
.course-info strong { font-size: 1.08rem; line-height: 1.55; }
.note-nav { display: grid; }
.note-nav button { display: grid; grid-template-columns: 30px 1fr; gap: 9px; align-items: start; padding: 13px 18px; border: 0; border-bottom: 1px solid var(--line); background: transparent; text-align: left; color: var(--muted); line-height: 1.35; }
.note-nav button span { color: var(--blue); font: 900 .7rem/1.4 ui-monospace, SFMono-Regular, Menlo, monospace; }
.note-nav button.active { background: var(--acid); color: var(--ink); font-weight: 850; }
.note-nav button.live::after { content: "LIVE"; justify-self: start; margin-top: 4px; padding: 3px 5px; background: var(--coral); color: white; font: 900 .58rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.follow-control { margin-top: auto; display: flex; align-items: center; gap: 9px; padding: 18px; border-top: 1px solid var(--ink); background: var(--white); font-size: .84rem; font-weight: 800; }
.follow-control input { width: 18px; height: 18px; accent-color: var(--blue); }
.reader-main { min-width: 0; }

.live-strip { min-height: 172px; display: grid; grid-template-columns: minmax(0, 1fr) 330px; border-bottom: 1px solid var(--ink); background: var(--blue); color: white; }
.live-chapter { display: grid; grid-template-columns: 75px 1fr; gap: 22px; align-items: center; padding: 28px clamp(24px, 5vw, 70px); }
.live-chapter > span { width: 64px; height: 64px; display: grid; place-items: center; border: 1px solid rgba(255,255,255,.65); font: 900 .77rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.live-chapter small, .mini-timer small { display: block; margin-bottom: 8px; color: var(--acid); font: 900 .68rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: .12em; }
.live-chapter b { display: block; font-size: clamp(1.35rem, 2.2vw, 2.3rem); line-height: 1.1; letter-spacing: -.035em; word-break: keep-all; }
.live-chapter p { margin: 9px 0 0; color: #ddddff; line-height: 1.45; }
.mini-timer { padding: 24px 26px; background: var(--ink); border-left: 1px solid rgba(255,255,255,.45); }
.mini-timer > div:first-child { display: flex; align-items: end; justify-content: space-between; gap: 12px; }
.mini-timer strong { font: 950 2.6rem/.9 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: -.08em; font-variant-numeric: tabular-nums; }
.mini-timer > span { display: inline-block; margin-top: 12px; padding: 4px 7px; background: #36363f; font: 900 .65rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.mini-timer.running > span { background: var(--coral); }
.timer-track { height: 7px; margin-top: 12px; background: #45454d; overflow: hidden; }
.timer-track i { display: block; width: 100%; height: 100%; background: var(--acid); transition: width .25s linear; }
.mini-timer p { margin: 9px 0 0; color: #b8b8c1; font-size: .78rem; line-height: 1.35; }

.notes-canvas { max-width: 1120px; margin: 0 auto; padding: clamp(34px, 6vw, 82px) clamp(22px, 6vw, 76px); }
.lecture-note { display: none; }
.lecture-note.active { display: block; animation: note-in .25s ease; }
@keyframes note-in { from { opacity: .2; transform: translateY(8px); } }
.note-heading { padding-bottom: 38px; border-bottom: 2px solid var(--ink); }
.note-heading h1, .console-head h1 { max-width: 940px; margin: 0; font-size: clamp(2.5rem, 5vw, 5.4rem); line-height: .98; letter-spacing: -.06em; word-break: keep-all; }
.note-heading .lead { max-width: 820px; margin: 24px 0 0; font-size: clamp(1.08rem, 1.7vw, 1.38rem); line-height: 1.68; color: #45454d; word-break: keep-all; }
.question-card { margin: 36px 0; padding: clamp(24px, 4vw, 42px); background: var(--blue); color: white; }
.question-card small, .case-label, .case-block small, .comparison-table small, .case-pair small, .identity-card small, .feed-section summary small { color: var(--acid); font: 900 .72rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: .08em; }
.question-card p { margin: 13px 0 0; font-size: clamp(1.5rem, 2.8vw, 2.8rem); line-height: 1.3; font-weight: 850; letter-spacing: -.035em; word-break: keep-all; }
.concept-grid { display: grid; margin: 34px 0; border: 1px solid var(--ink); background: white; }
.concept-grid.four { grid-template-columns: repeat(4, 1fr); }
.concept-grid section { min-height: 210px; padding: 22px; border-right: 1px solid var(--ink); }
.concept-grid section:last-child { border-right: 0; }
.concept-grid b { color: var(--blue); font-size: 1.05rem; }
.concept-grid p { line-height: 1.55; }
.concept-grid em { display: block; margin-top: 20px; color: var(--muted); font-style: normal; font-size: .84rem; }
.margin-note { display: grid; grid-template-columns: 150px 1fr; gap: 22px; margin: 30px 0; padding: 20px 0; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--ink); }
.margin-note b { color: var(--blue); }
.margin-note p { margin: 0; font-size: 1.08rem; line-height: 1.65; }
.learning-goals { margin-top: 45px; }
.learning-goals h2, .note-section h2, .case-block h2, .future-cone h2, .case-pair h2 { margin: 0 0 14px; font-size: clamp(1.6rem, 2.8vw, 2.6rem); letter-spacing: -.04em; }
.learning-goals ol { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; padding: 1px; background: var(--ink); counter-reset: goals; }
.learning-goals li { list-style: none; min-height: 105px; padding: 22px; background: white; line-height: 1.55; }
.before-after { display: grid; grid-template-columns: 1fr auto 1fr; align-items: stretch; margin: 36px 0; border: 1px solid var(--ink); background: white; }
.before-after section { padding: 26px; }
.before-after small { color: var(--blue); font-weight: 900; }
.before-after p { margin: 10px 0 0; font-size: 1.3rem; line-height: 1.5; font-weight: 750; }
.before-after i { display: grid; place-items: center; padding: 16px; background: var(--acid); font-size: 1.5rem; font-style: normal; }
.note-section { margin: 48px 0; }
.note-section > p, .note-section > div p { font-size: 1.04rem; line-height: 1.75; }
.note-section.split { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; padding: 1px; background: var(--ink); }
.note-section.split > div { padding: 28px; background: white; }
.diamond-flow { display: grid; grid-template-columns: repeat(4, 1fr); margin-top: 26px; }
.diamond-flow div { aspect-ratio: 1.7/1; display: grid; place-items: center; align-content: center; background: var(--soft-blue); clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%); margin-right: -14%; }
.diamond-flow div:nth-child(even) { background: var(--acid); }
.diamond-flow span { font-size: .8rem; margin-top: 5px; }
.case-block { margin: 36px 0; padding: 34px; border-left: 8px solid var(--blue); background: white; }
.case-block .case-label { color: var(--blue); }
.case-block p { line-height: 1.7; }
.case-block .caution { padding-top: 14px; border-top: 1px solid var(--line); color: var(--muted); }
.axis-table { margin: 36px 0; border: 1px solid var(--ink); background: white; }
.axis-row { display: grid; grid-template-columns: 1fr 1.15fr 1.65fr; gap: 20px; padding: 17px 20px; border-top: 1px solid var(--line); line-height: 1.45; }
.axis-row.head { border-top: 0; background: var(--ink); color: white; }
.axis-row strong { color: var(--blue); }
.research-chain, .exercise-steps { display: flex; align-items: stretch; gap: 8px; margin: 34px 0; overflow-x: auto; }
.research-chain span, .exercise-steps span { min-width: 120px; flex: 1; padding: 17px; border: 1px solid var(--ink); background: white; text-align: center; font-weight: 800; }
.research-chain i { align-self: center; color: var(--blue); font-style: normal; }
.myth, .measurement-note { display: grid; grid-template-columns: 165px 1fr; gap: 22px; padding: 24px; background: var(--acid); }
.myth p, .measurement-note p { margin: 0; line-height: 1.6; }
.aeiou-list { display: grid; grid-template-columns: repeat(5, 1fr); margin: 36px 0; border: 1px solid var(--ink); background: white; }
.aeiou-list > div { min-height: 190px; padding: 20px; border-right: 1px solid var(--ink); }
.aeiou-list > div:last-child { border-right: 0; }
.aeiou-list b { display: block; color: var(--blue); font-size: 2.8rem; line-height: 1; }
.aeiou-list span { display: block; margin-top: 7px; font: 800 .7rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.aeiou-list p { margin-top: 28px; font-size: .9rem; line-height: 1.5; }
.record-layers { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; padding: 1px; background: var(--ink); }
.record-layers div { padding: 23px; background: white; }
.record-layers small, .analysis-flow small { color: var(--blue); font: 900 .7rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.record-layers p { line-height: 1.6; }
.break-card { margin-top: 42px; min-height: 300px; display: grid; place-content: center; padding: 50px; background: var(--acid); border: 1px solid var(--ink); text-align: center; }
.break-card strong { font-size: clamp(2.5rem, 6vw, 6rem); letter-spacing: -.06em; }
.break-card p { max-width: 650px; font-size: 1.1rem; line-height: 1.7; }
.analysis-flow { display: grid; grid-template-columns: 1.4fr auto 1fr auto 1.2fr auto 1.2fr; gap: 8px; align-items: center; margin: 36px 0; }
.analysis-flow div { height: 100%; padding: 18px; border: 1px solid var(--ink); background: white; }
.analysis-flow i { color: var(--blue); font-style: normal; font-size: 1.5rem; }
.analysis-flow p { line-height: 1.5; }
.comparison-table { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; margin: 36px 0; padding: 1px; background: var(--ink); }
.comparison-table > div { padding: 30px; background: white; }
.comparison-table > div:last-child { background: var(--blue); color: white; }
.comparison-table > div:last-child small { color: var(--acid); }
.comparison-table p { font-size: 1.3rem; line-height: 1.5; }
.comparison-table b { font-size: .9rem; }
.future-cone { margin: 44px 0; }
.future-cone > div { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
.future-cone span { min-height: 115px; padding: 18px; border: 1px solid var(--ink); background: white; line-height: 1.4; }
.future-cone span b { display: block; margin-bottom: 10px; color: var(--blue); }
.future-cone span.preferred { background: var(--acid); }
.future-cone p { color: var(--muted); line-height: 1.6; }
.case-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.case-pair section { padding: 30px; background: var(--ink); color: white; }
.case-pair section:last-child { background: var(--blue); }
.case-pair p { line-height: 1.65; }
.exercise-steps span { text-align: left; }
.exercise-steps b { display: block; color: var(--blue); margin-bottom: 8px; }
.takeaway-list { margin: 38px 0; border-top: 2px solid var(--ink); }
.takeaway-list > div { display: grid; grid-template-columns: 80px 1fr; align-items: center; padding: 21px 0; border-bottom: 1px solid var(--ink); }
.takeaway-list b { color: var(--blue); font: 950 1.5rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.takeaway-list p { margin: 0; font-size: 1.12rem; }

.participation-card { margin-top: 54px; border: 2px solid var(--ink); background: white; box-shadow: 8px 8px 0 var(--blue); }
.participation-card.coral { box-shadow: 8px 8px 0 var(--coral); }
.participation-head { display: flex; justify-content: space-between; gap: 24px; padding: 26px 28px; background: var(--acid); border-bottom: 2px solid var(--ink); }
.participation-head span { display: inline-block; padding: 5px 8px; background: var(--blue); color: white; font: 900 .7rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.participation-head h2 { margin: 10px 0 0; font-size: 2rem; letter-spacing: -.04em; }
.participation-head p { margin: 8px 0 0; line-height: 1.55; }
.participation-head > b { white-space: nowrap; font: 950 2.5rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: -.08em; }
.answer-form { display: grid; gap: 19px; padding: 28px; }
label { display: grid; gap: 8px; font-size: .9rem; font-weight: 850; }
input, textarea, select { width: 100%; border: 1px solid var(--ink); border-radius: 0; background: white; color: var(--ink); padding: 12px 13px; outline: none; }
input:focus, textarea:focus, select:focus { box-shadow: 0 0 0 3px var(--acid); }
textarea { min-height: 105px; resize: vertical; line-height: 1.55; }
.artifact-text { min-height: 210px; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; background: #fffdf4; }
.two-fields, .three-fields { display: grid; gap: 16px; }
.two-fields { grid-template-columns: 1fr 1fr; }
.three-fields { grid-template-columns: repeat(3, 1fr); }
.submit-row { display: flex; align-items: center; justify-content: flex-end; gap: 14px; flex-wrap: wrap; padding-top: 18px; border-top: 1px solid var(--line); }
.share-check { display: flex; align-items: center; gap: 8px; margin-right: auto; }
.share-check input { width: 19px; height: 19px; accent-color: var(--blue); }
.save-status { min-width: 75px; color: var(--blue); font-weight: 850; }
.button { border: 1px solid var(--ink); border-radius: 0; padding: 12px 16px; background: white; color: var(--ink); font-weight: 900; box-shadow: 4px 4px 0 var(--ink); transition: .15s; }
.button:hover { transform: translate(2px, 2px); box-shadow: 2px 2px 0 var(--ink); }
.button.primary { background: var(--blue); color: white; }
.button.dark { background: var(--ink); color: white; }
.button.ghost { background: var(--paper); }

.identity-card, .feed-section { max-width: 1120px; margin: 0 auto 70px; }
.identity-card { display: grid; grid-template-columns: minmax(240px, 1fr) minmax(380px, 1.4fr); gap: 36px; padding: 30px clamp(22px, 5vw, 48px); border-top: 1px solid var(--ink); border-bottom: 1px solid var(--ink); background: white; }
.identity-card small { color: var(--blue); }
.identity-card h2 { margin: 9px 0; font-size: 1.5rem; letter-spacing: -.035em; }
.identity-card p { margin: 0; color: var(--muted); line-height: 1.55; }
.join-form { display: grid; grid-template-columns: 1fr 1fr auto; align-items: end; gap: 12px; }
.join-form .form-error { grid-column: 1/-1; }
.form-error { min-height: 1em; margin: 0; color: #aa2a1c; font-weight: 800; }
.participant-badge { align-self: center; padding: 22px; border: 1px solid var(--ink); background: var(--acid); }
.participant-badge b { display: block; font-size: 1.25rem; }
.participant-badge span { display: block; margin-top: 5px; color: var(--muted); }
.feed-section { background: white; border: 1px solid var(--ink); }
.feed-section summary { display: flex; justify-content: space-between; align-items: center; padding: 22px 26px; cursor: pointer; list-style: none; }
.feed-section summary::-webkit-details-marker { display: none; }
.feed-section summary small, .feed-section summary b { display: block; }
.feed-section summary small { margin-bottom: 6px; color: var(--blue); }
.feed-section summary i { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 50%; background: var(--acid); border: 1px solid var(--ink); font-style: normal; font-weight: 900; }
.feed-head { display: flex; justify-content: space-between; padding: 15px 26px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.feed-head p { margin: 0; color: var(--muted); }
.shared-feed, .responses { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; padding: 22px; }
.answer-card { padding: 19px; border: 1px solid var(--ink); background: var(--paper); }
.answer-card header { display: flex; justify-content: space-between; gap: 12px; padding-bottom: 12px; border-bottom: 1px solid var(--line); }
.answer-card header span { color: var(--blue); font: 800 .67rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace; }
.answer-card dl { display: grid; gap: 12px; margin: 16px 0 0; }
.answer-card dt { color: var(--blue); font: 850 .68rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.answer-card dd { margin: 4px 0 0; white-space: pre-wrap; line-height: 1.48; overflow-wrap: anywhere; }
.empty-state { grid-column: 1/-1; padding: 42px; border: 1px dashed var(--line); text-align: center; color: var(--muted); }

.instructor { padding: clamp(34px, 5vw, 68px) clamp(20px, 5vw, 70px); }
.console-head, .responses-head { display: flex; justify-content: space-between; gap: 24px; align-items: end; }
.console-head h1 { max-width: 800px; font-size: clamp(2.4rem, 4.5vw, 4.5rem); }
.console-head p { max-width: 700px; line-height: 1.6; }
.console-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.console-grid { display: grid; grid-template-columns: minmax(340px, .9fr) minmax(390px, 1.1fr); gap: 22px; margin-top: 32px; }
.agenda-panel, .control-panel, .responses-panel { padding: 24px; border: 1px solid var(--ink); background: white; box-shadow: 7px 7px 0 var(--ink); }
.agenda-panel h2, .responses-head h2 { margin: 0 0 18px; }
.agenda-list { display: grid; border-top: 1px solid var(--ink); }
.agenda-item { display: grid; grid-template-columns: 60px 1fr auto; gap: 12px; align-items: center; padding: 12px 7px; border: 0; border-bottom: 1px solid var(--line); background: transparent; text-align: left; }
.agenda-item.current { background: var(--acid); padding-inline: 12px; }
.agenda-item time, .agenda-item small { font: 800 .69rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.agenda-item time { color: var(--blue); }
.agenda-item span { font-weight: 780; }
.big-control-timer { padding: 28px; background: var(--acid); border: 1px solid var(--ink); }
.big-control-timer small, .big-control-timer span { display: block; font-weight: 900; }
.big-control-timer strong { display: block; margin: 12px 0; font: 950 clamp(4.5rem, 8vw, 8rem)/.9 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: -.1em; }
.timer-buttons { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-top: 18px; }
.minute-control { grid-template-columns: 1fr 100px; align-items: center; margin: 24px 0; }
.submission-overview { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
.count-card { padding: 13px; border: 1px solid var(--ink); }
.count-card b { display: block; color: var(--blue); font: 950 1.8rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.count-card span { display: block; margin-top: 7px; font-size: .7rem; font-weight: 800; }
.responses-panel { margin-top: 24px; }
.responses-head label { grid-template-columns: auto 170px; align-items: center; }
.ethics-note { display: grid; grid-template-columns: 150px 1fr; gap: 20px; margin: 0 clamp(20px, 5vw, 70px) 45px; padding: 22px; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--ink); background: var(--acid); }
.ethics-note p { margin: 0; line-height: 1.55; }
footer { display: flex; justify-content: space-between; gap: 20px; padding: 28px clamp(20px, 5vw, 70px) 42px; font: 800 .7rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.toast { position: fixed; right: 22px; bottom: 22px; z-index: 60; max-width: 350px; padding: 14px 17px; background: var(--ink); color: white; box-shadow: 5px 5px 0 var(--coral); transform: translateY(140%); transition: transform .23s; font-weight: 800; }
.toast.show { transform: translateY(0); }

@media (max-width: 1080px) {
  .reader-shell { grid-template-columns: 210px minmax(0, 1fr); }
  .live-strip { grid-template-columns: 1fr; }
  .mini-timer { display: grid; grid-template-columns: 1fr auto; align-items: center; border-left: 0; border-top: 1px solid rgba(255,255,255,.4); }
  .mini-timer .timer-track, .mini-timer p { grid-column: 1/-1; }
  .concept-grid.four { grid-template-columns: 1fr 1fr; }
  .concept-grid section:nth-child(2) { border-right: 0; }
  .concept-grid section:nth-child(-n+2) { border-bottom: 1px solid var(--ink); }
  .aeiou-list { grid-template-columns: 1fr 1fr; }
  .aeiou-list > div { border-bottom: 1px solid var(--ink); }
  .analysis-flow { grid-template-columns: 1fr; }
  .analysis-flow i { transform: rotate(90deg); justify-self: center; }
  .console-grid { grid-template-columns: 1fr; }
}

@media (max-width: 760px) {
  .topbar { height: 70px; }
  .brand small, .connection span { display: none; }
  .reader-shell { display: block; }
  .note-sidebar { position: static; height: auto; border-right: 0; }
  .course-info { display: none; }
  .note-nav { display: flex; overflow-x: auto; border-bottom: 1px solid var(--ink); }
  .note-nav button { flex: 0 0 180px; border-right: 1px solid var(--line); }
  .follow-control { position: sticky; top: 70px; z-index: 15; padding: 10px 15px; border-bottom: 1px solid var(--ink); }
  .live-chapter { grid-template-columns: 48px 1fr; padding: 22px 18px; }
  .live-chapter > span { width: 44px; height: 44px; }
  .notes-canvas { padding-block: 42px; }
  .note-heading h1 { font-size: 2.65rem; }
  .concept-grid.four, .learning-goals ol, .note-section.split, .comparison-table, .case-pair, .two-fields, .three-fields, .shared-feed, .responses { grid-template-columns: 1fr; }
  .concept-grid section { border-right: 0; border-bottom: 1px solid var(--ink); }
  .concept-grid section:last-child { border-bottom: 0; }
  .margin-note, .myth, .measurement-note { grid-template-columns: 1fr; }
  .before-after { grid-template-columns: 1fr; }
  .before-after i { transform: rotate(90deg); }
  .axis-row { grid-template-columns: 1fr; gap: 5px; }
  .axis-row.head { display: none; }
  .aeiou-list { grid-template-columns: 1fr; }
  .aeiou-list > div { min-height: 0; border-right: 0; }
  .record-layers, .future-cone > div { grid-template-columns: 1fr; }
  .participation-head { display: grid; }
  .identity-card { grid-template-columns: 1fr; }
  .join-form { grid-template-columns: 1fr; }
  .timer-buttons { grid-template-columns: 1fr; }
  .submission-overview { grid-template-columns: 1fr 1fr; }
  .console-head, .responses-head { display: grid; }
  .ethics-note { grid-template-columns: 1fr; }
}

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