:root {
  --ink: #152321;
  --ink-soft: #43524f;
  --paper: #f8f4eb;
  --paper-deep: #ece5d8;
  --white: #fffdf8;
  --teal: #176b64;
  --teal-dark: #0d4e49;
  --lime: #d5ef7f;
  --coral: #e97551;
  --line: #d8d2c5;
  --shadow: 0 18px 55px rgba(38, 51, 48, .10);
  --radius: 22px;
  --shell: min(1120px, calc(100vw - 40px));
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background:
    radial-gradient(circle at 85% 10%, rgba(213, 239, 127, .22), transparent 23rem),
    var(--paper);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}
a { color: inherit; }
button, input, select { font: inherit; }
button { cursor: pointer; }
.shell { width: var(--shell); margin-inline: auto; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.skip-link { position: fixed; z-index: 100; top: 10px; left: 10px; transform: translateY(-150%); background: var(--ink); color: white; padding: 10px 14px; border-radius: 8px; }
.skip-link:focus { transform: none; }

.site-header {
  width: var(--shell);
  margin: 18px auto 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px 12px 14px;
  border: 1px solid rgba(21, 35, 33, .09);
  border-radius: 18px;
  background: rgba(255, 253, 248, .82);
  backdrop-filter: blur(12px);
  position: relative;
  z-index: 10;
}
.brand { display: inline-flex; align-items: center; gap: 11px; font-weight: 850; letter-spacing: -.03em; text-decoration: none; font-size: 1.13rem; }
.brand-mark { width: 31px; height: 31px; border-radius: 9px; background: var(--teal); display: grid; align-content: center; gap: 3px; padding: 7px; transform: rotate(-2deg); }
.brand-mark i { display: block; height: 3px; border-radius: 10px; background: var(--lime); }
.brand-mark i:nth-child(2) { width: 75%; }
.brand-mark i:nth-child(3) { width: 45%; }
nav { display: flex; align-items: center; gap: 22px; }
nav a { text-decoration: none; font-size: .92rem; color: var(--ink-soft); font-weight: 700; }
nav a:hover, nav a:focus-visible { color: var(--teal); }

.eyebrow { margin: 0 0 10px; color: var(--teal); font-size: .72rem; font-weight: 850; letter-spacing: .14em; text-transform: uppercase; }
h1, h2, h3, p { text-wrap: pretty; }
h1, h2, h3 { line-height: 1.06; letter-spacing: -.045em; }
.hero { min-height: 615px; display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(290px, .7fr); gap: 90px; align-items: center; padding-block: 70px 55px; }
.hero h1 { max-width: 780px; margin: 0; font-family: Georgia, "Times New Roman", serif; font-size: clamp(3.5rem, 7.4vw, 6.9rem); font-weight: 500; }
.hero-lede { max-width: 650px; margin: 28px 0 0; font-size: clamp(1.04rem, 1.5vw, 1.25rem); color: var(--ink-soft); }
.hero-actions, .next-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 20px; margin-top: 30px; }
.button { min-height: 48px; display: inline-flex; align-items: center; justify-content: center; border: 1px solid transparent; border-radius: 13px; padding: 11px 20px; font-weight: 800; text-decoration: none; transition: transform .18s ease, box-shadow .18s ease, background .18s ease; }
.button:hover { transform: translateY(-2px); }
.button:focus-visible, input:focus-visible, select:focus-visible, summary:focus-visible, a:focus-visible { outline: 3px solid rgba(23, 107, 100, .30); outline-offset: 3px; }
.button-primary { background: var(--teal); color: white; box-shadow: 0 10px 25px rgba(23, 107, 100, .18); }
.button-primary:hover { background: var(--teal-dark); }
.button-secondary { background: transparent; border-color: var(--line); }
.text-link { font-weight: 800; text-decoration-thickness: 1px; text-underline-offset: 4px; }
.progress-card { align-self: end; margin-bottom: 30px; padding: 25px; border-radius: var(--radius); background: var(--ink); color: white; box-shadow: var(--shadow); transform: rotate(1.5deg); }
.progress-card-top { display: flex; justify-content: space-between; gap: 12px; font-size: .75rem; color: rgba(255,255,255,.68); text-transform: uppercase; letter-spacing: .09em; }
.status-dot { color: var(--lime); }
.progress-card > strong { display: block; margin-top: 26px; font-family: Georgia, serif; font-size: 5.2rem; font-weight: 400; line-height: .9; color: var(--lime); }
.progress-card > span { color: rgba(255,255,255,.75); }
.mini-rule { border-top: 1px solid rgba(255,255,255,.14); margin: 23px 0; }
.progress-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; }
.progress-pair b { display: block; font-size: 1.45rem; }
.progress-pair span { font-size: .8rem; color: rgba(255,255,255,.6); }

.principles { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.principles article { padding: 38px 30px 38px 0; }
.principles article + article { border-left: 1px solid var(--line); padding-left: 30px; }
.principles article > span { color: var(--coral); font-size: .75rem; font-weight: 900; }
.principles h2 { margin: 8px 0; font-size: 1.45rem; }
.principles p { margin: 0; color: var(--ink-soft); font-size: .92rem; }
.available { padding-block: 90px 110px; }
.section-heading { display: flex; justify-content: space-between; align-items: end; gap: 35px; margin-bottom: 28px; }
.section-heading h2 { margin: 0; font-family: Georgia, serif; font-size: clamp(2rem, 4vw, 3.5rem); font-weight: 500; }
.section-heading > p { max-width: 500px; margin: 0; color: var(--ink-soft); }
.family-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.family-card { position: relative; min-height: 260px; padding: 27px; border: 1px solid var(--line); border-radius: var(--radius); background: rgba(255, 253, 248, .65); text-decoration: none; overflow: hidden; transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease; }
.family-card::after { content: ""; position: absolute; width: 150px; height: 150px; right: -35px; bottom: -55px; border: 22px solid var(--lime); border-radius: 50%; opacity: .55; }
.family-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: rgba(23,107,100,.35); }
.family-code, .question-meta span { display: inline-flex; padding: 5px 9px; border-radius: 8px; background: var(--paper-deep); color: var(--ink-soft); font-size: .72rem; font-weight: 850; letter-spacing: .05em; text-transform: uppercase; }
.family-card h3 { max-width: 470px; margin: 38px 0 10px; font-family: Georgia, serif; font-size: 2.15rem; font-weight: 500; }
.family-card p { margin: 0; color: var(--ink-soft); }
.card-action { position: absolute; z-index: 1; bottom: 24px; left: 27px; color: var(--teal); font-weight: 800; }

.practice-shell, .result-shell, .admin-shell { padding-block: 60px 100px; }
.practice-header { display: flex; justify-content: space-between; align-items: end; gap: 20px; max-width: 900px; margin: 0 auto 22px; }
.practice-header h1 { margin: 0; font-family: Georgia, serif; font-size: clamp(2rem, 4vw, 3.3rem); font-weight: 500; }
.question-meta { display: flex; gap: 7px; }
.question-card { max-width: 900px; margin: 0 auto; padding: clamp(24px, 5vw, 52px); border: 1px solid var(--line); border-radius: 28px; background: var(--white); box-shadow: var(--shadow); }
.question-number { color: var(--coral); font-size: .75rem; font-weight: 900; text-transform: uppercase; letter-spacing: .1em; }
.question-stem { margin: 22px 0 32px; font-family: Georgia, serif; font-size: clamp(1.3rem, 2.4vw, 1.8rem); line-height: 1.55; white-space: normal; }
.question-stem.compact { font-size: 1.08rem; margin-bottom: 20px; }
.katex { white-space: nowrap; }
.question-media { max-width: 620px; margin: -8px auto 30px; }
.question-media.compact { margin-top: 0; }
.coordinate-plane { display: block; width: 100%; height: auto; border: 1px solid var(--line); border-radius: 19px; }
.coordinate-plane .graph-label { fill: #61706d; font: 11px ui-sans-serif, system-ui, sans-serif; }
.answers { display: grid; gap: 12px; border: 0; padding: 0; margin: 0; }
.answer-option { display: grid; grid-template-columns: 38px 1fr; align-items: center; gap: 15px; min-height: 62px; padding: 11px 16px; border: 1px solid var(--line); border-radius: 14px; cursor: pointer; transition: background .16s, border-color .16s, transform .16s; }
.answer-option:hover { border-color: var(--teal); transform: translateX(2px); }
.answer-option:has(input:checked) { border-color: var(--teal); background: rgba(213, 239, 127, .19); box-shadow: inset 4px 0 0 var(--teal); }
.answer-option input { position: absolute; opacity: 0; pointer-events: none; }
.answer-letter { display: grid; place-items: center; width: 34px; height: 34px; border: 1px solid var(--line); border-radius: 9px; font-weight: 850; }
.answer-option:has(input:checked) .answer-letter { background: var(--teal); color: white; border-color: var(--teal); }
.question-footer { display: flex; justify-content: space-between; align-items: center; gap: 20px; margin-top: 30px; }
.quiet { color: var(--ink-soft); font-size: .78rem; }

.result-banner { display: flex; align-items: center; gap: 25px; padding: 32px; border-radius: var(--radius); margin-bottom: 24px; }
.result-banner.is-correct { background: var(--teal); color: white; }
.result-banner.is-correct .eyebrow { color: var(--lime); }
.result-banner.is-review { background: #f2d9cb; }
.result-banner h1 { margin: 0; font-family: Georgia, serif; font-size: clamp(2.1rem, 4vw, 3.8rem); font-weight: 500; }
.result-banner p:last-child { margin: 8px 0 0; opacity: .75; }
.result-icon { display: grid; place-items: center; flex: 0 0 66px; width: 66px; height: 66px; border: 2px solid currentColor; border-radius: 50%; font-size: 2rem; }
.review-grid { display: grid; grid-template-columns: 1.08fr .92fr; gap: 22px; }
.review-card, .explanation-card, .panel { padding: 30px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--white); }
.review-card h2, .explanation-card h2, .panel h2 { margin: 0; font-family: Georgia, serif; font-size: 2rem; font-weight: 500; }
.answer-review { display: grid; gap: 8px; margin: 0; }
.answer-review div { display: grid; grid-template-columns: 120px 1fr; gap: 15px; padding: 12px 0; border-top: 1px solid var(--line); }
.answer-review dt { color: var(--ink-soft); font-size: .8rem; font-weight: 800; text-transform: uppercase; }
.answer-review dd { margin: 0; font-weight: 800; }
.misconception { display: grid; gap: 5px; margin-top: 22px; padding: 17px; border-left: 4px solid var(--coral); background: #fff3ed; }
.misconception span { color: var(--ink-soft); }

.admin-heading { display: flex; justify-content: space-between; align-items: center; gap: 40px; margin-bottom: 32px; }
.admin-heading h1 { margin: 0; font-family: Georgia, serif; font-size: clamp(2.8rem, 6vw, 5.2rem); font-weight: 500; }
.admin-heading > div:first-child > p:last-child { max-width: 650px; color: var(--ink-soft); }
.admin-lock { display: flex; align-items: center; gap: 12px; flex: 0 0 300px; padding: 16px; border: 1px solid var(--line); border-radius: 16px; background: var(--white); }
.admin-lock > span { display: grid; place-items: center; width: 38px; height: 38px; border-radius: 50%; background: var(--lime); }
.admin-lock strong, .admin-lock small { display: block; }
.admin-lock small { color: var(--ink-soft); margin-top: 2px; }
.admin-signout { display: flex; justify-content: flex-end; margin: -20px 0 20px; }
.text-button { appearance: none; border: 0; background: transparent; color: var(--plum); cursor: pointer; font: inherit; text-decoration: underline; text-underline-offset: 3px; }
.auth-shell { display: grid; min-height: 68vh; place-items: center; padding-block: 64px 96px; }
.auth-card { width: min(100%, 580px); text-align: center; }
.auth-card h1 { margin: 8px 0 16px; font-family: Georgia, serif; font-size: clamp(2.5rem, 7vw, 4.5rem); font-weight: 500; }
.auth-card .button { margin-top: 14px; }
.auth-note { margin: 24px auto 0; max-width: 460px; color: var(--ink-soft); font-size: .9rem; }
.auth-error { padding: 12px 14px; border: 1px solid #b53a47; border-radius: 10px; background: #fff1f2; color: #7d1e2b; }
.admin-grid { display: grid; grid-template-columns: 1.3fr .7fr; gap: 20px; }
.generator-form label { display: grid; gap: 7px; margin: 20px 0; font-size: .82rem; font-weight: 800; }
.label-note { color: var(--ink-soft); font-weight: 500; }
input, select { width: 100%; min-height: 49px; border: 1px solid var(--line); border-radius: 11px; background: white; color: var(--ink); padding: 10px 12px; }
.readiness-list { list-style: none; padding: 0; margin: 20px 0 0; }
.readiness-list li { display: grid; gap: 3px; padding: 12px 0; border-top: 1px solid var(--line); }
.readiness-list span { color: var(--ink-soft); font-size: .78rem; }
.readiness-list b { overflow-wrap: anywhere; }
.candidate-section { margin-top: 65px; }
.validation-badge { padding: 8px 12px; border-radius: 999px; font-size: .75rem; font-weight: 850; }
.validation-badge.valid { background: rgba(23,107,100,.12); color: var(--teal-dark); }
.validation-badge.invalid { background: #f5d7cb; color: #7b321f; }
.candidate-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 20px; align-items: start; }
.candidate-card { margin: 0; padding: 30px; }
.candidate-choices { display: grid; gap: 6px; padding-left: 30px; }
.candidate-choices li { padding: 7px 11px; border-radius: 8px; }
.candidate-correct { background: rgba(213,239,127,.4); font-weight: 800; }
.candidate-explanation { padding-top: 18px; border-top: 1px solid var(--line); color: var(--ink-soft); }
.json-panel { border: 1px solid var(--line); border-radius: var(--radius); background: var(--ink); color: white; overflow: hidden; }
.json-panel summary { padding: 18px 20px; cursor: pointer; font-weight: 800; }
.json-panel pre { max-height: 600px; overflow: auto; margin: 0; padding: 20px; border-top: 1px solid rgba(255,255,255,.14); color: #e8f2cf; font: .75rem/1.55 ui-monospace, SFMono-Regular, Consolas, monospace; white-space: pre-wrap; }
.error-list { padding: 15px 35px; border-radius: 12px; background: #f5d7cb; }
.error-shell { min-height: 65vh; display: grid; place-content: center; justify-items: start; }
.error-shell h1 { max-width: 780px; margin: 0 0 25px; font-family: Georgia, serif; font-size: clamp(2.2rem, 5vw, 4.3rem); font-weight: 500; }
.site-footer { width: var(--shell); margin: 0 auto; padding: 26px 0 38px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; gap: 25px; color: var(--ink-soft); font-size: .78rem; }

@media (max-width: 820px) {
  :root { --shell: min(100% - 28px, 1120px); }
  .hero { grid-template-columns: 1fr; gap: 20px; min-height: auto; padding-top: 70px; }
  .progress-card { max-width: 430px; margin: 20px 0; }
  .principles, .family-grid, .review-grid, .admin-grid, .candidate-grid { grid-template-columns: 1fr; }
  .principles article + article { border-left: 0; border-top: 1px solid var(--line); padding-left: 0; }
  .section-heading, .admin-heading { align-items: start; flex-direction: column; }
  .admin-lock { flex-basis: auto; width: 100%; }
}

@media (max-width: 560px) {
  .site-header { align-items: flex-start; }
  nav { flex-direction: column; align-items: flex-end; gap: 5px; }
  .hero h1 { font-size: 3.2rem; }
  .question-card { padding: 22px 17px; border-radius: 19px; }
  .question-footer, .practice-header, .site-footer { align-items: stretch; flex-direction: column; }
  .question-footer .button { width: 100%; }
  .result-banner { align-items: flex-start; }
  .result-icon { flex-basis: 48px; width: 48px; height: 48px; }
  .answer-review div { grid-template-columns: 1fr; gap: 3px; }
}

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