:root {
  --paper: #f2f6f3;
  --paper-light: #fbfcfa;
  --ink: #13252c;
  --muted: #5c6b6f;
  --line: #cad6d2;
  --violet: #153c4a;
  --violet-light: #d8e7e4;
  --amber: #b56a2c;
  --teal: #2f7d78;
  --dark: #102c35;
  --shadow: 0 18px 45px rgba(21, 60, 74, .08);
  --serif: Georgia, "Times New Roman", serif;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: var(--sans); line-height: 1.55; }
button, input { font: inherit; }
button { color: inherit; }
.view { display: none; }
.view.active { display: block; }

.skip-link { position: fixed; top: 8px; left: 8px; z-index: 100; padding: 10px 14px; color: white; background: var(--dark); transform: translateY(-150%); }
.skip-link:focus { transform: translateY(0); }
:focus-visible { outline: 3px solid rgba(47, 125, 120, .45); outline-offset: 3px; }

.masthead {
  position: sticky; top: 0; z-index: 20; min-height: 72px; display: flex; align-items: center; justify-content: space-between;
  gap: 24px; padding: 12px clamp(20px, 5vw, 76px); background: rgba(251,252,250,.97); border-bottom: 1px solid var(--line); box-shadow: 0 4px 18px rgba(21,60,74,.035);
}
.brand { display: flex; align-items: center; gap: 12px; border: 0; background: transparent; font-weight: 800; cursor: pointer; }
.brand-logo { width: 34px; height: 34px; display: block; filter: drop-shadow(0 4px 8px rgba(21,60,74,.12)); }
.main-nav { display: flex; align-items: center; justify-content: center; gap: clamp(10px, 2.5vw, 34px); margin-left: auto; }
.main-nav button { padding: 7px 0; border: 0; border-bottom: 2px solid transparent; color: var(--muted); background: transparent; font-size: .83rem; font-weight: 720; cursor: pointer; white-space: nowrap; }
.main-nav button:hover, .main-nav button.active { border-bottom-color: var(--violet); color: var(--violet); }
.header-actions { display: flex; align-items: center; gap: 18px; }
.prototype-chip { padding: 5px 9px; border: 1px solid #9fb9b3; border-radius: 999px; color: var(--teal); font-size: .66rem; font-weight: 820; letter-spacing: .07em; text-transform: uppercase; white-space: nowrap; }
.save-state { color: var(--muted); font-size: .82rem; }

.eyebrow { margin: 0 0 12px; color: var(--violet); font-size: .72rem; font-weight: 850; letter-spacing: .19em; text-transform: uppercase; }
h1, h2, h3, p { margin-top: 0; }
h1, h2, h3 { text-wrap: balance; }
.lede { color: #4f4a55; font-size: clamp(1.05rem, 2vw, 1.35rem); }

.primary-button, .quiet-button, .text-button {
  border-radius: 999px; cursor: pointer; transition: transform .15s ease, background .15s ease, color .15s ease, border-color .15s ease;
}
.primary-button { padding: 13px 23px; border: 1px solid var(--violet); background: var(--violet); color: white; font-weight: 750; box-shadow: 0 8px 20px rgba(21,60,74,.14); }
.primary-button:hover { transform: translateY(-1px); background: #0d303d; }
.primary-button.small { padding: 10px 16px; }
.quiet-button { padding: 12px 20px; border: 1px solid #aaa2b1; background: transparent; font-weight: 700; }
.quiet-button:hover { border-color: var(--violet); color: var(--violet); }
.text-button { padding: 8px 2px; border: 0; background: transparent; color: var(--violet); font-weight: 750; }
.text-button:hover { text-decoration: underline; }
.text-button.danger { margin-top: 28px; color: #8a403b; font-size: .85rem; }
button:disabled { opacity: .4; cursor: not-allowed; transform: none; }

.welcome-view { min-height: calc(100vh - 72px); }
.welcome-copy { padding: clamp(80px, 13vw, 175px) clamp(22px, 10vw, 150px) 90px; border-bottom: 1px solid var(--line); }
.welcome-copy h1 { max-width: 1050px; margin-bottom: 28px; font: 400 clamp(3.15rem, 8.3vw, 8rem)/.91 var(--serif); letter-spacing: -.055em; }
.welcome-copy .lede { max-width: 780px; }
.welcome-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 36px; }
.time-note { margin: 18px 0 0; color: var(--muted); font-size: .88rem; }
.home-status-row { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0; max-width: 1020px; margin-top: 42px; border: 1px solid var(--line); background: rgba(251,252,250,.65); }
.home-status-row > span { display: grid; gap: 3px; padding: 18px 20px; color: var(--muted); font-size: .75rem; }
.home-status-row > span + span { border-left: 1px solid var(--line); }
.home-status-row strong { color: var(--ink); font-size: .82rem; }
.principles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; max-width: 1220px; margin: 0 auto; border-left: 1px solid var(--line); }
.principles article { min-height: 300px; padding: 55px 44px; border-right: 1px solid var(--line); }
.principles article > span { color: var(--amber); font-weight: 850; }
.principles h2 { margin: 48px 0 14px; font: 400 clamp(1.6rem, 3vw, 2.35rem)/1 var(--serif); }
.principles p { color: var(--muted); }
.theory-note { display: grid; grid-template-columns: 170px 1fr; max-width: 1220px; margin: 0 auto 80px; padding: 28px 44px; color: #eee8f5; background: var(--dark); }
.theory-note p { margin: 0; max-width: 750px; }
.home-explainer { display: grid; grid-template-columns: minmax(280px, .9fr) minmax(320px, 1.1fr); gap: clamp(45px, 8vw, 120px); max-width: 1220px; margin: 0 auto; padding: 90px 44px; border-left: 1px solid var(--line); border-right: 1px solid var(--line); }
.home-explainer h2 { font: 400 clamp(2.3rem, 4.8vw, 4.4rem)/1 var(--serif); letter-spacing: -.035em; }
.home-explainer-copy { padding-top: 30px; }
.home-explainer-copy p { color: var(--muted); font-size: 1.04rem; }

.page-hero { padding: clamp(85px, 12vw, 160px) clamp(22px, 9vw, 140px) 95px; border-bottom: 1px solid var(--line); background: var(--paper-light); }
.page-hero h1 { max-width: 1100px; margin-bottom: 30px; font: 400 clamp(3rem, 7.3vw, 7rem)/.94 var(--serif); letter-spacing: -.05em; }
.page-hero .lede { max-width: 880px; }
.method-band { padding: 85px max(22px, calc((100vw - 1220px)/2)); }
.method-steps { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.method-steps article { min-height: 310px; padding: 30px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.method-steps article > span { color: var(--amber); font: 400 2rem/1 var(--serif); }
.method-steps h2 { margin: 65px 0 14px; font: 400 1.75rem/1.05 var(--serif); }
.method-steps p { color: var(--muted); }
.argument-section { display: grid; grid-template-columns: minmax(240px, .75fr) minmax(0, 1.25fr); gap: clamp(50px, 9vw, 140px); padding: 95px max(22px, calc((100vw - 1160px)/2)); color: #eeeaf1; background: var(--dark); }
.argument-intro h2 { font: 400 clamp(2.8rem, 5.5vw, 5.2rem)/.96 var(--serif); }
.argument-list article { padding: 0 0 30px; border-bottom: 1px solid #3c3942; }
.argument-list article + article { padding-top: 30px; }
.argument-list h3 { margin-bottom: 9px; font: 400 clamp(1.45rem, 2.5vw, 2.05rem)/1.1 var(--serif); }
.argument-list p { margin: 0; color: #bbb6c0; }
.evidence-ledger { display: grid; grid-template-columns: 1fr 1fr; }
.evidence-ledger > div { min-height: 360px; padding: 70px clamp(25px, 7vw, 100px); border-bottom: 1px solid var(--line); }
.evidence-ledger > div:first-child { border-right: 1px solid var(--line); }
.evidence-ledger h2 { font: 400 clamp(2.1rem, 4vw, 3.6rem)/1 var(--serif); }
.evidence-ledger p:last-child { color: var(--muted); }
.falsification-section { display: grid; grid-template-columns: .8fr 1.2fr; gap: clamp(50px, 9vw, 140px); padding: 95px max(22px, calc((100vw - 1160px)/2)); }
.falsification-section ul { margin: 0; padding: 0; list-style: none; }
.falsification-section li { padding: 20px 0 20px 42px; border-top: 1px solid var(--line); position: relative; }
.falsification-section li::before { position: absolute; left: 0; color: var(--violet); font-weight: 900; content: "→"; }
.references { padding: 95px max(22px, calc((100vw - 1050px)/2)); background: #e9e4d9; }
.references h2 { margin-bottom: 42px; font: 400 clamp(2.5rem, 5vw, 4.7rem)/1 var(--serif); }
.references ol { margin: 0; padding-left: 22px; }
.references li { padding: 14px 0 14px 8px; border-top: 1px solid #c9c1b3; overflow-wrap: anywhere; }
.references a { color: var(--violet); font-weight: 750; }
.reference-note { margin: 28px 0 0; color: var(--muted); font-size: .84rem; }

.library-hero .lede { max-width: 760px; }
.library-explanation { display: grid; grid-template-columns: repeat(3, 1fr); max-width: 1220px; margin: 0 auto; border-left: 1px solid var(--line); }
.library-explanation div { display: grid; align-content: center; min-height: 220px; padding: 38px; border-right: 1px solid var(--line); }
.library-explanation strong { font: 400 clamp(2.6rem, 5vw, 4.8rem)/1 var(--serif); }
.library-explanation span { margin-top: 10px; color: var(--muted); }
.catalog-tools { display: grid; grid-template-columns: auto minmax(260px, 600px) 1fr; align-items: center; gap: 18px; padding: 42px max(22px, calc((100vw - 1220px)/2)); border-block: 1px solid var(--line); }
.catalog-tools label { font-weight: 800; }
.catalog-tools input { width: 100%; padding: 13px 15px; border: 1px solid #aaa2ad; border-radius: 0; color: var(--ink); background: var(--paper-light); }
.catalog-tools input:focus { outline: 2px solid var(--violet-light); border-color: var(--violet); }
.catalog-tools span { justify-self: end; color: var(--muted); font-size: .84rem; }
.catalog-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; padding: 1px; background: var(--line); }
.profile-card { min-height: 220px; padding: 30px; background: var(--paper-light); }
.profile-card:hover { position: relative; z-index: 1; box-shadow: var(--shadow); }
.profile-card > span, .profile-card small { color: var(--muted); font-size: .68rem; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.profile-card h2 { margin: 35px 0 12px; font: 400 clamp(1.4rem, 2.6vw, 2.1rem)/1 var(--serif); }
.profile-card p { color: #55505a; }
.profile-card small { display: block; margin-top: 24px; }
.empty-catalog { grid-column: 1 / -1; padding: 80px; text-align: center; background: var(--paper); }
.catalog-pager { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; padding: 38px max(22px, calc((100vw - 800px)/2)); }
.catalog-pager > :last-child { justify-self: end; }
.catalog-pager span { color: var(--muted); font-size: .82rem; }
.library-note { display: grid; grid-template-columns: .8fr 1.2fr; gap: clamp(35px, 8vw, 110px); padding: 80px max(22px, calc((100vw - 1100px)/2)); color: #eeeaf1; background: var(--dark); }
.library-note h2 { font: 400 clamp(2.1rem, 4.5vw, 4rem)/1 var(--serif); }
.library-note p { color: #c5c0cb; font-size: 1.05rem; }

.test-shell { display: grid; grid-template-columns: minmax(240px, 330px) minmax(0, 1fr); min-height: calc(100vh - 72px); }
.test-rail { position: sticky; top: 72px; align-self: start; height: calc(100vh - 72px); overflow: auto; padding: 52px clamp(22px, 3.6vw, 54px); background: var(--dark); color: white; }
.test-rail .eyebrow { color: #c4b3ed; }
.test-rail h1 { margin-bottom: 42px; font: 400 2.2rem/1.05 var(--serif); }
.progress-number { display: flex; align-items: baseline; gap: 8px; }
.progress-number strong { font: 400 2.7rem/1 var(--serif); }
.progress-number span { color: #b9b5c0; font-size: .84rem; }
.progress-track { height: 3px; margin: 16px 0 36px; overflow: hidden; background: #4b4752; }
.progress-track span { display: block; width: 0; height: 100%; background: #c4b3ed; transition: width .2s ease; }
.section-nav { display: grid; }
.section-nav button { display: flex; justify-content: space-between; gap: 10px; padding: 9px 0; border: 0; color: #ddd9e2; background: transparent; text-align: left; cursor: pointer; }
.section-nav button:hover { color: white; }
.section-nav small { color: #8e8995; }
.question-stage { width: min(900px, 100%); margin: 0 auto; padding: 66px clamp(20px, 6vw, 78px) 90px; }
.question-header { display: flex; justify-content: space-between; align-items: end; gap: 24px; padding-bottom: 24px; border-bottom: 1px solid var(--line); }
.question-header h2 { margin: 0; font: 400 clamp(2rem, 4vw, 3.4rem)/1 var(--serif); }
.instruction { max-width: 720px; margin: 28px 0 38px; color: var(--muted); }
.question-list { display: grid; gap: 22px; }
.question-card { padding: 28px; border: 1px solid var(--line); border-radius: 8px; background: var(--paper-light); box-shadow: 0 7px 22px rgba(21,60,74,.035); }
.question-card.unanswered { border-left: 4px solid #aaa2ad; }
.question-card.answered { border-left: 4px solid var(--violet); }
.question-meta { display: flex; justify-content: space-between; margin-bottom: 12px; color: var(--muted); font-size: .7rem; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }
.question-card h3 { max-width: 700px; margin-bottom: 22px; font: 400 clamp(1.25rem, 2.5vw, 1.65rem)/1.28 var(--serif); }
.response-value { display: flex; align-items: baseline; gap: 11px; min-height: 31px; margin-bottom: 8px; }
.response-value strong { color: var(--violet); font-size: 1.35rem; }
.response-value span { color: #48434d; font-weight: 650; }
.answer-slider { width: 100%; height: 34px; margin: 0; accent-color: var(--violet); cursor: pointer; }
.unanswered .answer-slider { opacity: .55; }
.range-labels { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 8px; color: var(--muted); font-size: .72rem; }
.range-labels span:nth-child(2) { text-align: center; }
.range-labels span:last-child { text-align: right; }
.special-answers { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 20px; }
.special-answers button { padding: 6px 10px; border: 1px solid var(--line); border-radius: 5px; color: var(--muted); background: transparent; font-size: .73rem; cursor: pointer; }
.special-answers button:hover, .special-answers button.selected { border-color: var(--teal); color: var(--violet); background: #e5efec; }
.pager { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 16px; margin-top: 38px; }
.pager > :last-child { justify-self: end; }
.pager span { color: var(--muted); font-size: .82rem; }

.result-toolbar { position: sticky; top: 72px; z-index: 10; display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 12px clamp(20px, 5vw, 76px); border-bottom: 1px solid var(--line); background: rgba(243,239,230,.96); }
.result-toolbar > div { display: flex; gap: 8px; }
.profile-intro { padding: clamp(72px, 10vw, 130px) clamp(20px, 9vw, 140px) 85px; border-bottom: 1px solid var(--line); background: var(--paper-light); }
.profile-intro h1 { max-width: 1100px; margin-bottom: 30px; font: 400 clamp(3.2rem, 8vw, 7.5rem)/.93 var(--serif); letter-spacing: -.05em; }
.profile-intro .lede { max-width: 820px; }
.identity-line { display: flex; flex-wrap: wrap; gap: 34px; margin-top: 40px; padding-top: 22px; border-top: 1px solid var(--line); }
.identity-line span { color: var(--muted); }
.result-section { padding: 85px clamp(20px, 9vw, 140px); border-bottom: 1px solid var(--line); }
.section-heading { max-width: 820px; margin-bottom: 48px; }
.section-heading h2 { margin-bottom: 12px; font: 400 clamp(2.4rem, 5vw, 4.7rem)/.98 var(--serif); letter-spacing: -.035em; }
.section-heading > p:last-child { color: var(--muted); }
.paired-scales { display: grid; gap: 18px; }
.pair { display: grid; grid-template-columns: minmax(170px, 1fr) minmax(180px, 2fr) minmax(170px, 1fr); align-items: center; gap: 22px; padding: 24px 0; border-top: 1px solid var(--line); }
.pair-side { display: grid; gap: 3px; }
.pair-side.right { text-align: right; }
.pair-side span { color: var(--muted); font-size: .82rem; }
.dual-track { position: relative; height: 7px; overflow: hidden; background: #d9d3ca; }
.dual-track::after { position: absolute; top: -3px; left: 50%; width: 1px; height: 13px; background: #908995; content: ""; }
.dual-track span { position: absolute; top: 0; height: 100%; }
.left-fill { right: 50%; background: var(--violet); }
.right-fill { left: 50%; background: var(--amber); }
.profile-opening { display: grid; gap: 14px; max-width: 880px; color: #49434d; font: 400 clamp(1.12rem, 2vw, 1.35rem)/1.65 var(--serif); }
.profile-opening p { margin: 0; }
.portrait { background: #e6eeeb; }
.portrait-sections { display: grid; border-top: 1px solid #aebcb8; }
.portrait-card { display: grid; grid-template-columns: minmax(210px, .65fr) minmax(0, 1.35fr); gap: clamp(30px, 7vw, 100px); padding: 45px 0; border-bottom: 1px solid #aebcb8; }
.portrait-card h3 { margin: 0; font: 400 clamp(1.8rem, 3.5vw, 3.15rem)/1.02 var(--serif); letter-spacing: -.025em; }
.portrait-copy { display: grid; gap: 17px; }
.portrait-copy p { margin: 0; color: #373f3d; font: 400 clamp(1rem, 1.6vw, 1.16rem)/1.72 var(--serif); }
.highlights { color: #f3eff5; background: var(--dark); }
.highlights .section-heading > p:last-child { color: #aaa5b0; }
.highlight-list { margin: 0; padding: 0; list-style: none; counter-reset: highlights; }
.highlight-list li { display: grid; grid-template-columns: 70px minmax(0, 1fr); padding: 30px 0; border-top: 1px solid #3c3942; counter-increment: highlights; }
.highlight-list li::before { color: #b8a9dd; font: 400 2rem/1 var(--serif); content: "0" counter(highlights); }
.highlight-list strong { font: 400 clamp(1.35rem, 2.5vw, 2rem)/1.15 var(--serif); }
.highlight-list p { max-width: 760px; margin: 8px 0; color: #c5c1ca; }
.profile-layout { display: grid; grid-template-columns: minmax(210px, 290px) minmax(0, 1fr); gap: clamp(55px, 9vw, 145px); padding-left: max(20px, calc((100vw - 1180px)/2)); padding-right: max(20px, calc((100vw - 1180px)/2)); }
.chapter-nav { position: sticky; top: 158px; align-self: start; }
.chapter-nav div { display: grid; }
.chapter-nav a { padding: 7px 0; color: #4e4854; text-decoration: none; }
.chapter-nav a:hover { color: var(--violet); }
.chapter { border-top: 1px solid var(--line); }
.chapter:last-child { border-bottom: 1px solid var(--line); }
.chapter > summary { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 31px 0; cursor: pointer; list-style: none; }
.chapter > summary::-webkit-details-marker { display: none; }
.chapter > summary h3 { margin: 0; font: 400 clamp(1.75rem, 3.5vw, 3rem)/1 var(--serif); }
.chapter > summary span { color: var(--muted); font-size: .76rem; white-space: nowrap; }
.profile-paragraph { padding: 0 0 30px; }
.profile-paragraph > p { margin: 0; font: 400 clamp(1.05rem, 1.8vw, 1.28rem)/1.7 var(--serif); }
.unknowns { color: white; background: var(--violet); }
.unknowns .eyebrow { color: #e2d9f6; }
.unknown-grid { display: grid; grid-template-columns: repeat(2, 1fr); border-top: 1px solid rgba(255,255,255,.25); }
.unknown-grid > div { display: grid; gap: 6px; padding: 26px 25px 26px 0; border-bottom: 1px solid rgba(255,255,255,.25); }
.unknown-grid > div:nth-child(odd) { border-right: 1px solid rgba(255,255,255,.25); }
.unknown-grid > div:nth-child(even) { padding-left: 25px; }
.unknown-grid span { color: #d8d0e8; }
.appendix details > summary { display: flex; justify-content: space-between; gap: 20px; cursor: pointer; list-style: none; }
.appendix details > summary::-webkit-details-marker { display: none; }
.appendix summary > span:first-child { display: grid; }
.appendix summary strong { font: 400 clamp(1.8rem, 4vw, 3.4rem)/1 var(--serif); }
.appendix summary small { max-width: 620px; margin-top: 8px; color: var(--muted); font-size: .82rem; font-weight: 500; }
.appendix-body { margin-top: 35px; }
.technical-code { display: flex; align-items: baseline; justify-content: space-between; gap: 20px; margin-bottom: 24px; padding: 18px 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.technical-code span { color: var(--muted); font-size: .78rem; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.technical-code strong { font-family: var(--mono); font-size: clamp(.9rem, 2vw, 1.25rem); overflow-wrap: anywhere; }
.appendix-body h3 { margin: 55px 0 18px; font: 400 clamp(1.6rem, 3vw, 2.4rem)/1.1 var(--serif); }
.technical-narrative { border-top: 1px solid var(--line); }
.technical-narrative details { padding: 14px 0; border-bottom: 1px solid var(--line); }
.technical-narrative summary { cursor: pointer; font-weight: 750; }
.technical-narrative p { color: var(--muted); font-size: .78rem; overflow-wrap: anywhere; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: .78rem; }
th, td { padding: 10px 12px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--muted); letter-spacing: .08em; text-transform: uppercase; }
footer { padding: 42px clamp(20px, 5vw, 76px); color: #a9bec2; background: var(--dark); font-size: .8rem; }
.footer-inner { display: grid; grid-template-columns: .8fr 1.2fr; gap: 60px; max-width: 1180px; margin: 0 auto; }
.footer-inner strong { color: white; font-size: 1rem; }
.footer-inner p { margin: 5px 0 0; max-width: 720px; }
.fatal { padding: 100px 10vw; }

@media (max-width: 860px) {
  .masthead { flex-wrap: wrap; }
  .main-nav { order: 3; width: 100%; justify-content: flex-start; overflow-x: auto; }
  .header-actions { margin-left: auto; }
  .principles { grid-template-columns: 1fr; border-bottom: 1px solid var(--line); }
  .home-status-row { grid-template-columns: 1fr; }
  .home-status-row > span + span { border-left: 0; border-top: 1px solid var(--line); }
  .principles article { min-height: 0; border-bottom: 1px solid var(--line); }
  .theory-note { grid-template-columns: 1fr; gap: 8px; }
  .home-explainer, .argument-section, .falsification-section, .library-note { grid-template-columns: 1fr; }
  .method-steps { grid-template-columns: repeat(2, 1fr); }
  .evidence-ledger { grid-template-columns: 1fr; }
  .evidence-ledger > div:first-child { border-right: 0; }
  .library-explanation { grid-template-columns: 1fr; border-bottom: 1px solid var(--line); }
  .library-explanation div { min-height: 0; border-bottom: 1px solid var(--line); }
  .catalog-tools { grid-template-columns: 1fr; }
  .catalog-tools span { justify-self: start; }
  .catalog-grid { grid-template-columns: repeat(2, 1fr); }
  .test-shell { grid-template-columns: 1fr; }
  .test-rail { position: static; height: auto; }
  .section-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 18px; }
  .profile-layout { grid-template-columns: 1fr; }
  .result-toolbar { top: 111px; }
  .chapter-nav { position: static; }
  .chapter-nav div { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 18px; }
  .pair { grid-template-columns: 1fr 1fr; }
  .dual-track { grid-column: 1 / -1; grid-row: 2; }
  .unknown-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; gap: 24px; }
  .unknown-grid > div:nth-child(odd) { border-right: 0; }
  .unknown-grid > div:nth-child(even) { padding-left: 0; }
}

@media (max-width: 560px) {
  .masthead { min-height: 64px; }
  .prototype-chip { display: none; }
  .main-nav { gap: 22px; padding-bottom: 2px; }
  .main-nav button { font-size: .77rem; }
  .save-state { display: none; }
  .welcome-copy { padding-top: 72px; }
  .welcome-copy h1 { font-size: 3.4rem; }
  .principles article { padding: 38px 24px; }
  .principles h2 { margin-top: 24px; }
  .theory-note { margin-bottom: 0; padding: 25px; }
  .home-explainer { padding: 60px 24px; }
  .page-hero { padding-top: 75px; }
  .page-hero h1 { font-size: 3.25rem; }
  .method-steps { grid-template-columns: 1fr; }
  .method-steps article { min-height: 0; }
  .method-steps h2 { margin-top: 35px; }
  .catalog-grid { grid-template-columns: 1fr; }
  .profile-card { min-height: 0; }
  .test-rail { padding: 34px 22px; }
  .test-rail h1 { margin-bottom: 24px; font-size: 1.9rem; }
  .test-rail .progress-track { margin-bottom: 22px; }
  .section-nav { display: flex; gap: 10px; margin-inline: -22px; padding: 0 22px 8px; overflow-x: auto; scroll-snap-type: x proximity; }
  .section-nav button { flex: 0 0 168px; display: grid; gap: 5px; padding: 12px; border: 1px solid #45414c; border-radius: 5px; scroll-snap-align: start; }
  .section-nav button small { justify-self: start; }
  .test-rail .text-button.danger { margin-top: 14px; }
  .question-stage { padding-top: 42px; }
  .question-header { align-items: start; }
  .question-card { padding: 23px 18px; }
  .range-labels span:nth-child(2) { display: none; }
  .range-labels { grid-template-columns: 1fr 1fr; }
  .result-toolbar { top: 111px; align-items: start; }
  .result-toolbar > div { flex-direction: column; }
  .profile-intro h1 { font-size: 3rem; }
  .pair { gap: 12px; }
  .portrait-card { grid-template-columns: 1fr; gap: 22px; }
  .pair-side strong { font-size: .87rem; }
  .highlight-list li { grid-template-columns: 46px 1fr; }
  .chapter-nav div { grid-template-columns: 1fr; }
  .pager { grid-template-columns: 1fr 1fr; }
  .pager span { grid-column: 1 / -1; grid-row: 1; text-align: center; }
}

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