:root {
  color-scheme: dark;
  --bg: #07111f;
  --panel: rgba(15, 31, 51, 0.94);
  --panel-2: #16283f;
  --panel-3: #0b1728;
  --text: #eef6ff;
  --muted: #9fb3c8;
  --accent: #38bdf8;
  --accent-strong: #0284c7;
  --danger: #fb7185;
  --success: #34d399;
  --warning: #fbbf24;
  --border: rgba(255, 255, 255, 0.12);
  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-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(56, 189, 248, 0.18), transparent 30%),
    radial-gradient(circle at top right, rgba(52, 211, 153, 0.12), transparent 25%),
    linear-gradient(180deg, #0a1730 0%, var(--bg) 36%);
  color: var(--text);
}

button,
input,
select {
  font: inherit;
}

button {
  transition: transform 120ms ease, border-color 120ms ease, background-color 120ms ease, box-shadow 120ms ease;
}

button:hover:not(:disabled) {
  transform: translateY(-1px);
}

button:focus-visible,
select:focus-visible {
  outline: 3px solid rgba(56, 189, 248, 0.65);
  outline-offset: 2px;
}

.app-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 42px 0 56px;
}

.hero,
.exam-screen,
.results-screen {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: clamp(20px, 4vw, 48px);
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.32);
}

.hero {
  display: grid;
  gap: 18px;
}

.eyebrow {
  margin: 0;
  color: var(--accent);
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: clamp(2.2rem, 7vw, 5rem);
  line-height: 1.02;
}

h2 {
  margin-bottom: 10px;
  font-size: clamp(1.45rem, 3vw, 2rem);
}

h3 {
  margin-bottom: 8px;
}

.lede,
.muted,
.reference,
.status-message,
.review-list span,
.recent-attempts span,
.recent-attempts time {
  color: var(--muted);
}

.status-message {
  min-height: 1.25rem;
  margin: 0;
  font-weight: 600;
}

.status-message.error {
  color: #fda4af;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 12px;
}

.hero-stats div,
.score-chip,
.review-preview,
.explanation-card {
  border: 1px solid var(--border);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.04);
}

.hero-stats div {
  display: grid;
  gap: 4px;
  padding: 14px 16px;
}

.hero-stats strong {
  font-size: 1.15rem;
}

.hero-stats span {
  color: var(--muted);
}

.exam-config {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 6px;
}

.exam-config label {
  display: grid;
  gap: 8px;
  color: var(--muted);
  font-weight: 700;
}

.exam-config select {
  width: 100%;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--text);
  padding: 10px 12px;
}

.primary-button,
.secondary-button,
.answer-option {
  border: 0;
  border-radius: 14px;
  cursor: pointer;
}

.primary-button,
.secondary-button {
  padding: 12px 18px;
  font-weight: 800;
}

.primary-button {
  background: linear-gradient(180deg, #38bdf8, #0ea5e9);
  color: #04111f;
}

.secondary-button {
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid var(--border);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
  transform: none;
}

.hidden {
  display: none !important;
}

.exam-screen,
.results-screen {
  display: grid;
  gap: 22px;
  margin-top: 24px;
}

.exam-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
}

.header-meta {
  text-align: right;
}

.timer {
  margin: 0 0 6px;
  color: var(--warning);
  font-weight: 900;
  font-variant-numeric: tabular-nums;
}

.progress-track {
  height: 10px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), var(--success));
}

.question-card {
  display: grid;
  gap: 18px;
  padding: 24px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border);
}

.question-prompt {
  margin: 0;
  font-size: clamp(1.1rem, 2vw, 1.28rem);
  line-height: 1.55;
}

.answer-list {
  display: grid;
  gap: 12px;
}

.answer-option {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 12px;
  align-items: start;
  width: 100%;
  padding: 16px;
  text-align: left;
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid var(--border);
}

.answer-option:hover,
.answer-option.selected {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.18);
}

.answer-option.correct-answer {
  border-color: rgba(52, 211, 153, 0.8);
  background: rgba(52, 211, 153, 0.12);
}

.answer-option.wrong-answer {
  border-color: rgba(251, 113, 133, 0.9);
  background: rgba(251, 113, 133, 0.14);
}

.option-id {
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 999px;
  background: rgba(56, 189, 248, 0.16);
  color: var(--accent);
  font-weight: 900;
}

.option-text {
  line-height: 1.5;
}

.explanation-card {
  padding: 18px;
}

.explanation-card.correct {
  border-color: rgba(52, 211, 153, 0.55);
}

.explanation-card.incorrect {
  border-color: rgba(251, 113, 133, 0.55);
}

.reference {
  margin-bottom: 0;
  font-size: 0.95rem;
}

.exam-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.results-summary {
  display: grid;
  gap: 14px;
}

.score-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.score-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  color: var(--text);
}

.score-chip.success {
  background: rgba(52, 211, 153, 0.12);
  border-color: rgba(52, 211, 153, 0.5);
}

.review-preview {
  padding: 20px;
}

.all-answers-summary {
  gap: 12px;
}

.all-answers-list {
  display: grid;
  gap: 18px;
}

.all-answer-card {
  display: grid;
  gap: 16px;
  padding: 22px;
  border-radius: 20px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.03);
}

.all-answer-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
}

.review-status-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 110px;
  padding: 8px 12px;
  border-radius: 999px;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
}

.review-status-chip.correct {
  color: #052016;
  background: rgba(52, 211, 153, 0.92);
}

.review-status-chip.incorrect {
  color: #28070f;
  background: rgba(251, 113, 133, 0.92);
}

.review-answer-list .answer-option {
  cursor: default;
}

.all-answers-empty {
  padding: 20px;
  border-radius: 18px;
  border: 1px dashed var(--border);
  background: rgba(255, 255, 255, 0.02);
}

.review-list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.review-list li {
  display: grid;
  gap: 4px;
  padding: 12px 14px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.04);
}

.recent-attempts {
  margin-top: 28px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.recent-attempts ul {
  display: grid;
  gap: 10px;
  padding: 0;
  list-style: none;
}

.recent-attempts li {
  display: grid;
  gap: 4px;
  padding: 12px 14px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.05);
}

.recent-attempts strong {
  color: var(--text);
}

@media (max-width: 720px) {
  .app-shell {
    width: min(100% - 18px, 1180px);
    padding: 18px 0 28px;
  }

  .hero,
  .exam-screen,
  .results-screen {
    border-radius: 18px;
    padding: 18px;
  }

  .exam-header,
  .exam-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .header-meta {
    text-align: left;
  }

  .primary-button,
  .secondary-button {
    width: 100%;
  }

  .answer-option {
    grid-template-columns: 34px 1fr;
    padding: 14px;
  }

  .all-answer-header {
    flex-direction: column;
  }

  .review-status-chip {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0ms !important;
    animation-duration: 0ms !important;
    animation-iteration-count: 1 !important;
  }
}