@import url("https://fonts.googleapis.com/css2?family=Barlow+Condensed:ital,wght@0,600;0,700;0,800;0,900;1,800&family=Inter:wght@400;500;600;700;800&display=swap");

:root {
  --ink: #020711;
  --ink-2: #07142a;
  --panel: rgba(5, 17, 37, 0.82);
  --line: rgba(129, 203, 255, 0.24);
  --blue: #0a5bff;
  --cyan: #58c2ff;
  --ice: #dff5ff;
  --white: #ffffff;
  --muted: #98abc4;
  --green: #52e3ad;
  --red: #ff738d;
  --shadow: 0 30px 80px rgba(0, 0, 0, 0.48);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  color: var(--white);
  background:
    radial-gradient(circle at 80% 9%, rgba(10, 91, 255, 0.2), transparent 28rem),
    radial-gradient(circle at 8% 53%, rgba(18, 151, 255, 0.1), transparent 30rem),
    var(--ink);
  font-family: Inter, Arial, sans-serif;
}
button, input, select { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; }
[hidden] { display: none !important; }
.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; }

.ambient {
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.2;
  background-image: linear-gradient(rgba(88,194,255,.035) 1px, transparent 1px), linear-gradient(90deg, rgba(88,194,255,.035) 1px, transparent 1px);
  background-size: 72px 72px;
  mask-image: linear-gradient(to bottom, black, transparent 75%);
}

.topbar {
  position: relative;
  z-index: 5;
  min-height: 92px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
  max-width: 1420px;
  margin: auto;
  padding: 18px 32px;
  border-bottom: 1px solid rgba(125, 199, 255, 0.16);
}
.back-link, .ghost-button, .quiz-back {
  color: var(--ice);
  text-decoration: none;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .05em;
}
.back-link { justify-self: start; display: inline-flex; gap: 9px; align-items: center; }
.back-link span, .quiz-back span { color: var(--cyan); font-size: 20px; }
.brand { text-decoration: none; text-align: center; line-height: .88; letter-spacing: .12em; }
.brand span { display: block; color: var(--cyan); font-family: "Barlow Condensed", sans-serif; font-size: 13px; font-weight: 800; }
.brand strong { font-family: "Barlow Condensed", sans-serif; font-size: 26px; font-style: italic; text-shadow: 0 0 18px rgba(88,194,255,.35); }
.ghost-button, .quiz-back { justify-self: end; border: 0; background: none; cursor: pointer; }
.ghost-button:hover, .back-link:hover, .quiz-back:hover { color: var(--cyan); }

main { position: relative; z-index: 1; }
.hero { max-width: 1320px; margin: auto; padding: 92px 32px 90px; }
.eyebrow { color: var(--cyan); text-transform: uppercase; letter-spacing: .24em; font-size: 12px; font-weight: 800; }
.eyebrow span { display: inline-block; width: 34px; height: 2px; margin: 0 12px 3px 0; background: var(--cyan); box-shadow: 0 0 12px var(--cyan); }
h1, .finish-card h2 {
  max-width: 850px;
  margin: 20px 0 24px;
  font-family: "Barlow Condensed", Impact, sans-serif;
  font-size: clamp(70px, 9.5vw, 138px);
  font-weight: 900;
  font-style: italic;
  line-height: .76;
  letter-spacing: -.035em;
  color: #eefbff;
  -webkit-text-stroke: 1px #fff;
  text-shadow: 2px 3px 0 #0a5bff, 5px 7px 0 rgba(0,33,95,.7), 0 0 34px rgba(88,194,255,.24);
}
h1 em, .finish-card h2 em { color: #71ccff; font-style: italic; }
.hero-copy { max-width: 650px; margin: 0; color: #b8c9dc; font-size: 17px; line-height: 1.75; }

.stats { display: grid; grid-template-columns: repeat(4, 1fr); margin: 58px 0 86px; border: 1px solid var(--line); background: rgba(4,14,31,.65); box-shadow: var(--shadow); backdrop-filter: blur(14px); }
.stats article { min-height: 130px; display: flex; flex-direction: column; justify-content: center; padding: 24px 32px; border-right: 1px solid var(--line); }
.stats article:last-child { border: 0; }
.stats strong { font-family: "Barlow Condensed", sans-serif; font-size: 42px; line-height: 1; color: var(--ice); }
.stats span { margin-top: 9px; color: var(--muted); font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: .13em; }

.control-panel { display: grid; grid-template-columns: 1fr 1.45fr; gap: 34px; align-items: end; padding: 34px; border: 1px solid rgba(88,194,255,.27); background: linear-gradient(135deg, rgba(10,91,255,.12), rgba(4,14,31,.75) 45%); box-shadow: inset 0 1px rgba(255,255,255,.05), 0 18px 65px rgba(0,0,0,.3); }
.control-panel > div:first-child, .section-heading > div { display: flex; gap: 18px; align-items: flex-start; }
.section-index { color: var(--cyan); font-family: "Barlow Condensed", sans-serif; font-weight: 800; font-size: 20px; }
.control-panel h2, .section-heading h2 { margin: 0; font-family: "Barlow Condensed", sans-serif; font-size: 30px; font-style: italic; letter-spacing: .04em; }
.control-panel p { margin: 7px 0 0; color: var(--muted); font-size: 13px; line-height: 1.5; }
.filters { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.filters label:not(.toggle-label) { display: block; }
.filters label > span:first-child { display: block; margin-bottom: 7px; color: var(--muted); font-size: 10px; font-weight: 800; text-transform: uppercase; letter-spacing: .12em; }
select, .search-box input { width: 100%; color: var(--white); background: #07152d; border: 1px solid rgba(125,199,255,.26); border-radius: 0; outline: none; }
select { height: 46px; padding: 0 12px; }
select:focus, .search-box input:focus { border-color: var(--cyan); box-shadow: 0 0 0 3px rgba(88,194,255,.1); }
.toggle-label { display: flex; align-items: center; gap: 11px; color: #cbd9e8; font-size: 12px; cursor: pointer; }
.toggle-label input { position: absolute; opacity: 0; }
.toggle { position: relative; width: 38px; height: 22px; border-radius: 99px; background: #17243a; border: 1px solid #334862; }
.toggle::after { content: ""; position: absolute; width: 14px; height: 14px; top: 3px; left: 4px; border-radius: 50%; background: #93a8bd; transition: .2s; }
.toggle-label input:checked + .toggle { background: var(--blue); border-color: var(--cyan); }
.toggle-label input:checked + .toggle::after { left: 18px; background: white; box-shadow: 0 0 8px white; }
.primary-button, .secondary-button { min-height: 46px; border: 0; padding: 0 22px; font-weight: 800; font-size: 12px; letter-spacing: .06em; text-transform: uppercase; cursor: pointer; transition: transform .2s, box-shadow .2s, opacity .2s; }
.primary-button { color: #fff; background: linear-gradient(135deg, #0a5bff, #168fee); box-shadow: 0 10px 28px rgba(10,91,255,.3), inset 0 1px rgba(255,255,255,.3); }
.secondary-button { color: var(--ice); border: 1px solid rgba(125,199,255,.32); background: #07152d; }
.primary-button:hover, .secondary-button:hover { transform: translateY(-2px); }
.primary-button:disabled { opacity: .38; cursor: not-allowed; transform: none; }

.catalog { margin-top: 84px; }
.section-heading { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-bottom: 28px; }
.search-box { position: relative; width: min(330px, 100%); }
.search-box input { height: 46px; padding: 0 42px 0 15px; }
.search-box > span:last-child { position: absolute; right: 15px; top: 8px; color: var(--cyan); font-size: 26px; }
.loading, .empty-state { padding: 50px; text-align: center; color: var(--muted); border: 1px dashed var(--line); }
.subject-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.subject-card { position: relative; min-height: 230px; display: flex; flex-direction: column; padding: 25px; color: inherit; text-align: left; overflow: hidden; border: 1px solid rgba(125,199,255,.2); background: linear-gradient(145deg, rgba(10,91,255,.11), rgba(4,14,31,.9) 42%); box-shadow: 0 14px 38px rgba(0,0,0,.22); cursor: pointer; transition: transform .25s, border-color .25s, box-shadow .25s; }
.subject-card::before { content: ""; position: absolute; width: 160px; height: 160px; right: -80px; top: -88px; border-radius: 50%; background: var(--cyan); opacity: .09; filter: blur(15px); }
.subject-card:hover { transform: translateY(-5px); border-color: rgba(88,194,255,.7); box-shadow: 0 22px 58px rgba(0,33,91,.38); }
.subject-card .card-top { display: flex; justify-content: space-between; color: var(--muted); font-size: 10px; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }
.subject-card h3 { flex: 1; display: flex; align-items: center; max-width: 88%; margin: 22px 0; font-family: "Barlow Condensed", sans-serif; font-size: 28px; font-style: italic; line-height: 1.02; text-transform: uppercase; }
.subject-card .card-progress { display: grid; grid-template-columns: 1fr auto; gap: 8px 12px; align-items: center; color: #a9bad0; font-size: 10px; font-weight: 700; }
.mini-track { grid-column: 1 / -1; height: 4px; overflow: hidden; background: #132239; }
.mini-track span { display: block; height: 100%; background: linear-gradient(90deg, var(--blue), var(--cyan)); box-shadow: 0 0 10px var(--cyan); }

.legacy-note { margin-top: 54px; display: flex; align-items: center; justify-content: space-between; gap: 22px; padding: 22px 26px; border: 1px solid rgba(125,199,255,.17); background: rgba(5,17,37,.66); }
.legacy-note > div { display: flex; align-items: center; gap: 16px; }
.archive-mark { display: grid; place-items: center; width: 38px; height: 38px; color: var(--cyan); font-size: 25px; border: 1px solid rgba(88,194,255,.38); }
.legacy-note strong, .legacy-note span { display: block; }
.legacy-note strong { margin-bottom: 4px; font-size: 13px; }
.legacy-note div span { color: var(--muted); font-size: 11px; }
.legacy-note a { color: var(--cyan); text-decoration: none; font-size: 11px; font-weight: 800; text-transform: uppercase; letter-spacing: .09em; }

.quiz-view { min-height: calc(100vh - 92px); padding: 54px 24px 90px; }
.quiz-shell { max-width: 980px; margin: auto; }
.quiz-back { justify-self: auto; display: inline-flex; align-items: center; gap: 9px; padding: 0; }
.quiz-progress { margin: 40px 0 18px; }
.quiz-progress > div:first-child { display: flex; justify-content: space-between; margin-bottom: 10px; color: var(--muted); font-size: 11px; font-weight: 800; text-transform: uppercase; letter-spacing: .1em; }
.quiz-progress strong { color: var(--cyan); }
.progress-track { height: 5px; background: #14223a; overflow: hidden; }
.progress-track span { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--blue), var(--cyan)); box-shadow: 0 0 12px var(--cyan); transition: width .3s; }
.question-card { padding: clamp(25px, 5vw, 56px); border: 1px solid rgba(125,199,255,.26); background: linear-gradient(150deg, rgba(10,91,255,.1), rgba(4,14,31,.94) 38%); box-shadow: var(--shadow); }
.question-card > header { display: flex; align-items: flex-start; justify-content: space-between; gap: 15px; padding-bottom: 28px; border-bottom: 1px solid rgba(125,199,255,.15); }
.question-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.question-tags span { padding: 7px 9px; color: var(--cyan); border: 1px solid rgba(88,194,255,.3); background: rgba(10,91,255,.08); font-size: 9px; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.question-id { color: #60758f; font-size: 10px; font-weight: 700; text-transform: uppercase; }
.question-topic { margin: 30px 0 10px; color: var(--cyan); font-size: 11px; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.question-card h2 { max-width: 850px; margin: 0 0 34px; font-size: clamp(20px, 3vw, 29px); line-height: 1.5; }
fieldset { padding: 0; border: 0; }
.answers { display: grid; gap: 11px; }
.answer-option { position: relative; display: grid; grid-template-columns: 38px 1fr; gap: 14px; align-items: center; min-height: 62px; padding: 11px 16px 11px 12px; border: 1px solid rgba(125,199,255,.19); background: rgba(4,17,36,.76); cursor: pointer; transition: border .2s, background .2s, transform .2s; }
.answer-option:hover { border-color: rgba(88,194,255,.56); transform: translateX(3px); }
.answer-option input { position: absolute; opacity: 0; }
.answer-letter { display: grid; place-items: center; width: 36px; height: 36px; color: var(--cyan); border: 1px solid rgba(88,194,255,.3); font-family: "Barlow Condensed", sans-serif; font-size: 18px; font-weight: 800; }
.answer-copy { color: #d7e3ef; font-size: 13px; line-height: 1.55; }
.answer-option.selected { border-color: var(--cyan); background: rgba(10,91,255,.15); box-shadow: 0 0 0 2px rgba(88,194,255,.07); }
.answer-option.correct { border-color: var(--green); background: rgba(82,227,173,.1); }
.answer-option.incorrect { border-color: var(--red); background: rgba(255,115,141,.1); }
.answer-option.locked { cursor: default; transform: none; }
.quiz-actions { display: flex; justify-content: flex-end; gap: 12px; margin-top: 28px; }
.feedback { margin-top: 30px; padding: 28px; border: 1px solid rgba(125,199,255,.2); background: rgba(1,8,18,.72); }
.feedback-title { display: flex; align-items: center; gap: 12px; color: var(--ice); }
.feedback-title span { display: grid; place-items: center; width: 28px; height: 28px; color: #02120e; background: var(--green); border-radius: 50%; font-weight: 900; }
.feedback-title.is-wrong span { color: #190309; background: var(--red); }
.feedback > p { color: #b9c9da; font-size: 13px; line-height: 1.75; }
.feedback .legal-source { padding-top: 16px; border-top: 1px solid rgba(125,199,255,.13); color: #8499b1; font-size: 11px; }
.glossary-links { display: flex; flex-wrap: wrap; gap: 7px; margin: 18px 0; }
.glossary-links a { padding: 6px 8px; color: var(--cyan); text-decoration: none; border: 1px solid rgba(88,194,255,.22); font-size: 9px; font-weight: 700; text-transform: uppercase; }
.feedback .primary-button { display: block; margin: 22px 0 0 auto; }

.dialog-backdrop { position: fixed; z-index: 20; inset: 0; display: grid; place-items: center; padding: 24px; background: rgba(0,4,10,.84); backdrop-filter: blur(10px); }
.finish-card { position: relative; width: min(590px, 100%); padding: 48px; overflow: hidden; text-align: center; border: 1px solid rgba(88,194,255,.45); background: #061329; box-shadow: 0 0 90px rgba(10,91,255,.28); }
.finish-glow { position: absolute; width: 300px; height: 300px; top: -220px; left: 50%; transform: translateX(-50%); border-radius: 50%; background: var(--cyan); opacity: .25; filter: blur(45px); }
.finish-card h2 { margin: 18px auto 28px; font-size: clamp(50px, 10vw, 82px); }
.finish-card > strong { display: block; color: var(--cyan); font-family: "Barlow Condensed", sans-serif; font-size: 54px; }
.finish-card > p:not(.eyebrow) { color: var(--muted); font-size: 13px; }
.finish-card > div { display: flex; justify-content: center; gap: 12px; margin-top: 28px; }

@media (max-width: 900px) {
  .control-panel { grid-template-columns: 1fr; }
  .subject-grid { grid-template-columns: repeat(2, 1fr); }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stats article:nth-child(2) { border-right: 0; }
  .stats article:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
}

@media (max-width: 620px) {
  .topbar { min-height: 64px; grid-template-columns: 1fr auto; padding: 9px 14px; }
  .brand { grid-column: 2; grid-row: 1; }
  .brand strong { font-size: 21px; }
  .ghost-button { display: none; }
  .back-link { max-width: 130px; font-size: 10px; line-height: 1.25; }
  .hero { padding: 34px 15px 44px; }
  .eyebrow { font-size: 10px; }
  h1 { margin: 14px 0 18px; font-size: clamp(56px, 19vw, 82px); line-height: .82; }
  .hero-copy { font-size: 14px; line-height: 1.55; }
  .stats { margin: 28px 0 36px; }
  .stats article { min-height: 88px; padding: 13px 14px; }
  .stats strong { font-size: 32px; }
  .control-panel { padding: 19px 15px; }
  .filters { grid-template-columns: 1fr; }
  .catalog { margin-top: 38px; }
  .section-heading { align-items: stretch; flex-direction: column; }
  .section-heading > div { align-items: center; }
  .search-box { width: 100%; }
  .subject-grid { grid-template-columns: 1fr; gap: 12px; }
  .subject-card { min-height: 155px; padding: 19px; }
  .subject-card h3 { margin: 15px 0; }
  .legacy-note { align-items: flex-start; flex-direction: column; margin-top: 34px; }
  .quiz-view { padding: 32px 14px 60px; }
  .question-card { padding: 22px 17px; }
  .question-card > header { flex-direction: column; }
  .answer-option { grid-template-columns: 34px 1fr; gap: 10px; padding-right: 10px; }
  .quiz-actions { display: grid; grid-template-columns: 1fr 1fr; }
  .feedback { padding: 21px 17px; }
  .finish-card { padding: 38px 20px; }
  .finish-card > div { flex-direction: column; }
}

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