:root {
  color-scheme: light;
  --navy-950: #071c2c;
  --navy-900: #0b2638;
  --navy-800: #123b52;
  --navy-700: #1c526b;
  --sea-600: #087e83;
  --sea-500: #0f9a98;
  --sea-100: #dff4f0;
  --sand-100: #f4efe3;
  --sand-50: #fbf9f3;
  --ink: #102533;
  --muted: #5d6c75;
  --line: #d8e0e2;
  --white: #ffffff;
  --success: #157347;
  --success-bg: #e7f6ed;
  --danger: #b23a34;
  --danger-bg: #fff0ed;
  --warning: #a66512;
  --shadow: 0 18px 50px rgba(7, 28, 44, 0.1);
  --radius-lg: 24px;
  --radius-md: 16px;
  --radius-sm: 10px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    radial-gradient(circle at 92% 6%, rgba(15, 154, 152, 0.11), transparent 23rem),
    linear-gradient(180deg, var(--sand-50) 0, #fff 38rem);
}

button, input, select { font: inherit; }
button { color: inherit; }
a { color: var(--sea-600); }

button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible {
  outline: 3px solid rgba(15, 154, 152, 0.35);
  outline-offset: 3px;
}

.hidden { display: none !important; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  min-height: 76px;
  padding: 0 5vw;
  color: var(--white);
  background: rgba(7, 28, 44, 0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.8rem;
  color: inherit;
  text-decoration: none;
  letter-spacing: -0.015em;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  color: var(--sea-100);
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.brand strong, .brand small { display: block; }
.brand strong { font-family: Georgia, "Times New Roman", serif; font-size: 1.16rem; }
.brand small { margin-top: 0.12rem; color: #acc4ce; font-size: 0.72rem; letter-spacing: 0.13em; text-transform: uppercase; }

.main-nav { display: flex; align-items: center; gap: 0.2rem; }
.main-nav { scrollbar-width: none; }
.main-nav::-webkit-scrollbar { display: none; }
.main-nav button {
  border: 0;
  padding: 0.65rem 0.8rem;
  color: #c7d8df;
  background: transparent;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.88rem;
}
.main-nav button:hover, .main-nav button.active { color: #fff; background: rgba(255, 255, 255, 0.09); }

main { width: min(1180px, 90vw); min-height: calc(100vh - 150px); margin: 0 auto; padding: 4.5rem 0 6rem; }
main:focus { outline: none; }
.view { animation: view-in 240ms ease both; }

@keyframes view-in { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

h1, h2, h3, p { margin-top: 0; }
h1, h2 { font-family: Georgia, "Times New Roman", serif; color: var(--navy-950); letter-spacing: -0.025em; }
h1 { font-size: clamp(2.3rem, 6vw, 4.9rem); line-height: 0.98; }
h2 { font-size: clamp(1.6rem, 3vw, 2.45rem); line-height: 1.08; }

.eyebrow {
  margin-bottom: 0.75rem;
  color: var(--sea-600);
  font-size: 0.74rem;
  font-weight: 800;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.hero-grid { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(340px, 0.75fr); gap: clamp(2rem, 6vw, 6rem); align-items: center; }
.hero-copy { padding: 2.5rem 0; }
.hero-copy h1 { max-width: 760px; margin-bottom: 1.5rem; }
.hero-lede { max-width: 650px; color: var(--muted); font-size: clamp(1.02rem, 2vw, 1.25rem); line-height: 1.65; }

.hero-stats { display: flex; flex-wrap: wrap; gap: 1.7rem; margin-top: 2.2rem; }
.hero-stats span { color: var(--muted); font-size: 0.8rem; letter-spacing: 0.05em; text-transform: uppercase; }
.hero-stats strong { display: block; margin-bottom: 0.12rem; color: var(--navy-900); font-family: Georgia, serif; font-size: 1.65rem; letter-spacing: -0.02em; }

.exam-builder, .result-panel, .navigator-panel {
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid rgba(18, 59, 82, 0.1);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}
.exam-builder { padding: clamp(1.4rem, 4vw, 2rem); }
.panel-heading h2 { margin-bottom: 1.25rem; }

.segmented-control { display: grid; grid-template-columns: 1fr 1fr; margin: 0 0 1.25rem; padding: 4px; border: 0; border-radius: 12px; background: #edf2f2; }
.segmented-control legend { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.segmented-control label { cursor: pointer; }
.segmented-control input { position: absolute; opacity: 0; }
.segmented-control span { display: block; padding: 0.72rem; border-radius: 9px; color: var(--muted); text-align: center; font-weight: 700; }
.segmented-control input:checked + span { color: var(--navy-900); background: #fff; box-shadow: 0 3px 10px rgba(7, 28, 44, 0.09); }

.field-label { display: block; margin-bottom: 0.5rem; font-size: 0.82rem; font-weight: 750; }
select, .search-box input { width: 100%; border: 1px solid var(--line); color: var(--ink); background: #fff; }
select { height: 48px; padding: 0 0.8rem; border-radius: 10px; }

.toggle-row { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin: 1.25rem 0; cursor: pointer; }
.toggle-row strong, .toggle-row small { display: block; }
.toggle-row strong { font-size: 0.9rem; }
.toggle-row small { margin-top: 0.2rem; color: var(--muted); font-size: 0.77rem; line-height: 1.35; }
.toggle-row input { position: relative; width: 44px; height: 24px; flex: 0 0 auto; appearance: none; border-radius: 20px; background: #c8d2d5; cursor: pointer; transition: 180ms ease; }
.toggle-row input::after { content: ""; position: absolute; top: 3px; left: 3px; width: 18px; height: 18px; border-radius: 50%; background: #fff; box-shadow: 0 2px 5px rgba(0, 0, 0, 0.22); transition: 180ms ease; }
.toggle-row input:checked { background: var(--sea-600); }
.toggle-row input:checked::after { transform: translateX(20px); }

.button { min-height: 44px; border: 1px solid transparent; border-radius: 10px; padding: 0.7rem 1.05rem; cursor: pointer; font-weight: 750; transition: transform 150ms ease, background 150ms ease, border 150ms ease; }
.button:hover { transform: translateY(-1px); }
.button:disabled { opacity: 0.46; cursor: not-allowed; transform: none; }
.button-primary { color: #fff; background: var(--navy-900); }
.button-primary:hover:not(:disabled) { background: var(--navy-800); }
.button-secondary { color: var(--navy-900); background: #edf3f3; border-color: #d8e3e3; }
.button-ghost { color: var(--navy-800); background: transparent; border-color: var(--line); }
.button-block { width: 100%; margin-top: 0.65rem; }
.panel-hint { min-height: 1.1rem; margin: 0.8rem 0 0; color: var(--muted); font-size: 0.75rem; text-align: center; }

.compact-heading { margin-top: 5.5rem; }
.section-heading { display: flex; justify-content: space-between; align-items: flex-end; gap: 2rem; margin-bottom: 2.3rem; }
.section-heading h1, .section-heading h2 { margin-bottom: 0.6rem; }
.section-heading h1 { font-size: clamp(2.3rem, 5vw, 4.2rem); }
.section-heading p:last-child { max-width: 680px; color: var(--muted); line-height: 1.6; }

.quick-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.quick-card { min-height: 180px; padding: 1.45rem; border: 1px solid var(--line); border-radius: var(--radius-md); color: inherit; background: rgba(255, 255, 255, 0.7); text-align: left; cursor: pointer; transition: 180ms ease; }
.quick-card:hover { border-color: var(--sea-500); transform: translateY(-3px); box-shadow: 0 14px 35px rgba(7, 28, 44, 0.08); }
.quick-card strong, .quick-card small { display: block; }
.quick-card strong { margin: 1.6rem 0 0.35rem; font-family: Georgia, serif; font-size: 1.3rem; }
.quick-card small { color: var(--muted); line-height: 1.5; }
.quick-icon { color: var(--sea-600); font-size: 0.72rem; font-weight: 800; letter-spacing: 0.14em; }

.topic-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }
.topic-card { position: relative; display: flex; min-height: 245px; flex-direction: column; padding: 1.35rem; overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius-md); background: #fff; }
.topic-card::after { content: ""; position: absolute; right: -30px; bottom: -55px; width: 130px; height: 130px; border: 22px solid var(--sea-100); border-radius: 50%; opacity: 0.7; }
.topic-number { color: var(--sea-600); font-size: 0.72rem; font-weight: 800; letter-spacing: 0.14em; }
.topic-card h2 { margin: 1.35rem 0 0.65rem; font-size: 1.42rem; }
.topic-card p { color: var(--muted); font-size: 0.87rem; line-height: 1.5; }
.topic-card footer { position: relative; z-index: 1; display: flex; align-items: center; justify-content: space-between; margin-top: auto; padding: 0; border: 0; }
.topic-card footer span { font-size: 0.78rem; font-weight: 700; }
.topic-card footer button { border: 0; color: var(--sea-600); background: transparent; cursor: pointer; font-weight: 800; }

.search-box { display: flex; align-items: center; gap: 0.7rem; max-width: 760px; padding: 0 1rem; border: 1px solid var(--line); border-radius: 14px; background: #fff; box-shadow: 0 8px 25px rgba(7, 28, 44, 0.05); }
.search-box span { color: var(--sea-600); font-size: 1.6rem; }
.search-box input { height: 58px; border: 0; outline: 0; font-size: 1rem; }
.result-summary { min-height: 1.5rem; margin: 1.2rem 0; color: var(--muted); font-size: 0.85rem; }
.search-results { display: grid; gap: 0.8rem; }
.search-card { display: grid; grid-template-columns: 1fr auto; gap: 1rem; padding: 1.25rem; border: 1px solid var(--line); border-radius: 14px; background: #fff; }
.search-card h2 { margin-bottom: 0.45rem; font-family: inherit; font-size: 1.02rem; line-height: 1.45; letter-spacing: 0; }
.search-card p { margin: 0; color: var(--muted); font-size: 0.78rem; }

.materials-list { display: grid; gap: 0.9rem; }
.material-card { display: grid; grid-template-columns: 48px 1fr auto; gap: 1.1rem; align-items: center; padding: 1.2rem; border: 1px solid var(--line); border-radius: 14px; background: #fff; }
.material-index { display: grid; place-items: center; width: 46px; height: 46px; border-radius: 50%; color: var(--navy-900); background: var(--sea-100); font-family: Georgia, serif; }
.material-card h2 { margin: 0 0 0.35rem; font-family: inherit; font-size: 1.04rem; letter-spacing: 0; }
.material-card p { margin: 0; color: var(--muted); font-size: 0.82rem; line-height: 1.5; }
.source-meta { color: var(--muted); font-size: 0.78rem; white-space: nowrap; }
.material-link { display: inline-block; margin-top: 0.35rem; font-size: 0.78rem; font-weight: 750; }

.progress-summary { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; margin-bottom: 2.5rem; }
.summary-card { padding: 1.25rem; border: 1px solid var(--line); border-radius: 14px; background: #fff; }
.summary-card strong { display: block; margin-bottom: 0.25rem; font-family: Georgia, serif; font-size: 2rem; }
.summary-card span { color: var(--muted); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.08em; }
.category-history { display: grid; gap: 0.75rem; margin-bottom: 2rem; }
.history-list { display: grid; gap: 0.6rem; }
.history-row { display: grid; grid-template-columns: 1fr auto auto; gap: 1rem; padding: 0.9rem 1rem; border-bottom: 1px solid var(--line); font-size: 0.86rem; }
.history-row time, .history-row span { color: var(--muted); }
.empty-state { padding: 3rem; border: 1px dashed #bdcace; border-radius: var(--radius-md); color: var(--muted); text-align: center; }

.exam-topbar { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: 1rem; }
.exam-topbar p { display: inline; margin: 0 0 0 0.65rem; color: var(--muted); font-size: 0.86rem; }
.mode-badge, .question-meta span { display: inline-flex; align-items: center; min-height: 26px; padding: 0.25rem 0.6rem; border-radius: 999px; font-size: 0.7rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; }
.mode-badge { color: #fff; background: var(--sea-600); }
.progress-track { height: 5px; margin-bottom: 2rem; overflow: hidden; border-radius: 5px; background: #dfe7e8; }
.progress-track span { display: block; width: 0; height: 100%; border-radius: inherit; background: var(--sea-500); transition: width 180ms ease; }
.exam-layout { display: grid; grid-template-columns: minmax(0, 1fr) 280px; gap: 1.5rem; align-items: start; }
.question-panel { min-height: 590px; padding: clamp(1.5rem, 4vw, 3rem); border: 1px solid rgba(18, 59, 82, 0.1); border-radius: var(--radius-lg); background: rgba(255, 255, 255, 0.94); box-shadow: var(--shadow); }
.question-meta { display: flex; gap: 0.55rem; margin-bottom: 1.35rem; }
.question-meta span:first-child { color: var(--sea-600); background: var(--sea-100); }
.question-meta span:last-child { color: var(--navy-700); background: #edf2f4; }
.question-panel h1 { max-width: 840px; margin-bottom: 2rem; font-family: Georgia, serif; font-size: clamp(1.5rem, 3vw, 2.25rem); line-height: 1.25; }
.choice-list { display: grid; gap: 0.75rem; }
.choice { display: grid; grid-template-columns: 34px 1fr; gap: 0.8rem; align-items: center; width: 100%; min-height: 62px; padding: 0.8rem 1rem; border: 1px solid var(--line); border-radius: 12px; color: var(--ink); background: #fff; text-align: left; cursor: pointer; transition: 150ms ease; }
.choice:hover:not(:disabled) { border-color: var(--sea-500); background: #f7fcfb; }
.choice.selected { border-color: var(--navy-800); background: #edf4f6; }
.choice.correct { border-color: #69ad87; background: var(--success-bg); }
.choice.incorrect { border-color: #d98c84; background: var(--danger-bg); }
.choice:disabled { cursor: default; }
.choice-letter { display: grid; place-items: center; width: 30px; height: 30px; border: 1px solid #c9d4d7; border-radius: 50%; font-size: 0.76rem; font-weight: 800; }
.choice.selected .choice-letter { color: #fff; border-color: var(--navy-800); background: var(--navy-800); }
.practice-feedback { margin-top: 1rem; padding: 1rem 1.1rem; border-left: 4px solid var(--success); border-radius: 0 10px 10px 0; background: var(--success-bg); line-height: 1.55; }
.practice-feedback.wrong { border-color: var(--danger); background: var(--danger-bg); }
.practice-feedback strong { display: block; margin-bottom: 0.35rem; }
.source-line { display: block; margin-top: 0.7rem; color: var(--muted); font-size: 0.78rem; }
.source-line a { font-weight: 700; }
.exam-actions { display: flex; justify-content: space-between; gap: 1rem; margin-top: 2rem; }
.navigator-panel { position: sticky; top: 98px; padding: 1.2rem; }
.navigator-heading { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: 1rem; }
.navigator-heading span { color: var(--muted); font-size: 0.7rem; }
.question-navigator { display: grid; grid-template-columns: repeat(5, 1fr); gap: 0.42rem; }
.question-navigator button { aspect-ratio: 1; border: 1px solid var(--line); border-radius: 8px; background: #fff; cursor: pointer; font-size: 0.72rem; font-weight: 700; }
.question-navigator button.answered { color: #fff; border-color: var(--navy-700); background: var(--navy-700); }
.question-navigator button.current { color: var(--navy-950); border: 2px solid var(--sea-500); background: var(--sea-100); }
.navigator-key { display: grid; gap: 0.45rem; margin-top: 1.2rem; color: var(--muted); font-size: 0.68rem; }
.navigator-key span { display: flex; align-items: center; gap: 0.45rem; }
.navigator-key i { width: 11px; height: 11px; border: 1px solid var(--line); border-radius: 3px; background: #fff; }
.navigator-key .key-current { border: 2px solid var(--sea-500); background: var(--sea-100); }
.navigator-key .key-answered { border-color: var(--navy-700); background: var(--navy-700); }

.result-hero { padding: clamp(2rem, 6vw, 4.5rem); border-radius: var(--radius-lg); color: #fff; background: linear-gradient(130deg, var(--navy-950), var(--navy-800)); text-align: center; box-shadow: var(--shadow); }
.result-hero .eyebrow { color: #8ed8cf; }
.result-hero h1 { margin-bottom: 0.8rem; color: #fff; font-size: clamp(3.4rem, 9vw, 6.6rem); }
.result-status { display: inline-block; margin: 0.6rem 0 1.3rem; padding: 0.4rem 0.85rem; border: 1px solid rgba(255,255,255,.28); border-radius: 999px; font-size: 0.8rem; font-weight: 850; letter-spacing: 0.16em; }
.result-figures { display: flex; flex-wrap: wrap; justify-content: center; gap: 1.5rem; color: #c2d7df; font-size: 0.82rem; }
.results-grid { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 1rem; margin-top: 1rem; }
.result-panel { padding: 1.5rem; box-shadow: none; }
.result-panel h2 { font-size: 1.55rem; }
.category-score { margin-bottom: 1rem; }
.category-score header { display: flex; justify-content: space-between; gap: 1rem; margin-bottom: 0.4rem; padding: 0; color: var(--ink); background: transparent; border: 0; font-size: 0.82rem; }
.category-score .bar { height: 7px; overflow: hidden; border-radius: 6px; background: #e5ecec; }
.category-score .bar span { display: block; height: 100%; border-radius: inherit; background: var(--sea-500); }
.result-actions { display: grid; gap: 0.75rem; }
.review-section { margin-top: 4rem; }
.review-card { margin-bottom: 0.9rem; padding: 1.3rem; border: 1px solid var(--line); border-radius: 14px; background: #fff; }
.review-card h3 { margin-bottom: 1rem; font-family: Georgia, serif; line-height: 1.35; }
.review-answer { display: grid; grid-template-columns: 150px 1fr; gap: 0.7rem; margin: 0.35rem 0; font-size: 0.86rem; }
.review-answer span:first-child { color: var(--muted); }
.review-explanation { margin: 0.9rem 0 0; padding-top: 0.9rem; border-top: 1px solid var(--line); color: var(--muted); font-size: 0.86rem; line-height: 1.55; }

.loading-view, .error-view { display: grid; min-height: 55vh; place-items: center; align-content: center; text-align: center; }
.loader { width: 38px; height: 38px; border: 3px solid #d5e5e5; border-top-color: var(--sea-600); border-radius: 50%; animation: spin 0.8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.error-view h1 { max-width: 720px; font-size: clamp(2rem, 5vw, 3.8rem); }
.error-view p { max-width: 680px; color: var(--muted); }
.error-view code { padding: 0.7rem 1rem; border-radius: 8px; background: #e9efef; }

footer { display: flex; justify-content: space-between; gap: 1rem; padding: 1.5rem 5vw; color: #80929b; background: var(--navy-950); font-size: 0.74rem; }

@media (max-width: 980px) {
  .site-header { align-items: flex-start; flex-direction: column; gap: 0.65rem; padding-top: 0.8rem; padding-bottom: 0.65rem; }
  .main-nav { width: 100%; overflow-x: auto; }
  .main-nav button { white-space: nowrap; }
  .hero-grid, .exam-layout, .results-grid { grid-template-columns: 1fr; }
  .exam-builder { max-width: 640px; }
  .topic-grid { grid-template-columns: repeat(2, 1fr); }
  .navigator-panel { position: static; order: -1; }
  .question-navigator { grid-template-columns: repeat(10, 1fr); }
}

@media (max-width: 680px) {
  main { width: min(92vw, 1180px); padding-top: 2.5rem; }
  .brand strong { font-size: 1.02rem; }
  .hero-copy { padding: 1rem 0; }
  .hero-grid { gap: 1.25rem; }
  .compact-heading { margin-top: 4rem; }
  .quick-grid, .topic-grid, .progress-summary { grid-template-columns: 1fr; }
  .section-heading { align-items: flex-start; flex-direction: column; }
  .material-card { grid-template-columns: 42px 1fr; }
  .source-meta { grid-column: 2; white-space: normal; }
  .search-card { grid-template-columns: 1fr; }
  .question-panel { min-height: 0; padding: 1.25rem; }
  .question-navigator { grid-template-columns: repeat(8, 1fr); }
  .exam-actions { position: sticky; bottom: 0; margin: 1.5rem -0.5rem -0.5rem; padding: 0.75rem 0.5rem; background: rgba(255,255,255,.95); }
  .review-answer { grid-template-columns: 1fr; gap: 0.15rem; }
  footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}