:root {
  color-scheme: light;
  --bg: #f4f1ea;
  --panel: #fffdf8;
  --panel-strong: #ffffff;
  --ink: #1f2a2e;
  --muted: #66757d;
  --line: #d8d0c4;
  --accent: #1d6f5f;
  --accent-soft: #d7efe9;
  --danger: #a84432;
  --danger-action: #2b2f31;
  --danger-soft: #f8ddd7;
  --success: #206246;
  --success-soft: #dcf4e5;
  --shadow: 0 18px 45px rgba(43, 49, 52, 0.08);
  --radius: 18px;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #101418;
  --panel: #171c21;
  --panel-strong: #1e252b;
  --ink: #eef4f2;
  --muted: #a8b4ba;
  --line: #344149;
  --accent: #7ee0c5;
  --accent-strong: #0f5f52;
  --accent-soft: #18372f;
  --danger: #ff9b85;
  --danger-action: #8f3328;
  --danger-soft: #3b211f;
  --success: #84d9a9;
  --success-soft: #183225;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.32);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(29, 111, 95, 0.12), transparent 28%),
    radial-gradient(circle at top right, rgba(168, 68, 50, 0.08), transparent 20%),
    linear-gradient(180deg, #f8f5ee 0%, var(--bg) 100%);
}

html[data-theme="dark"] body {
  background:
    radial-gradient(circle at top left, rgba(78, 195, 166, 0.16), transparent 28%),
    radial-gradient(circle at top right, rgba(255, 155, 133, 0.1), transparent 20%),
    linear-gradient(180deg, #111820 0%, var(--bg) 100%);
}

.app-shell {
  width: min(960px, calc(100% - 32px));
  margin: 32px auto 48px;
}

.hero,
.card {
  background: color-mix(in srgb, var(--panel) 94%, transparent);
  border: 1px solid color-mix(in srgb, var(--line) 85%, transparent);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 28px;
  margin-bottom: 22px;
}

.eyebrow {
  margin: 0 0 8px;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.hero h1 {
  margin: 0 0 8px;
  font-size: clamp(2rem, 3vw, 2.7rem);
}

.switch-row {
  display: flex;
  flex-wrap: nowrap;
  gap: 6px;
  align-items: center;
  margin-bottom: 14px;
}

.mode-controls {
  display: inline-flex;
  flex-wrap: nowrap;
  gap: 6px;
  align-items: center;
  min-width: 0;
}

.profile-switch {
  display: grid;
  grid-template-columns: repeat(2, 64px);
  gap: 4px;
  height: 46px;
  padding: 0;
  border: 1px solid color-mix(in srgb, var(--line) 90%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--panel-strong) 62%, var(--line));
}

.profile-btn,
.language-toggle-btn,
.difficulty-toggle-btn,
.theme-toggle-btn {
  width: 44px;
  height: 44px;
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  font-weight: 700;
}

.profile-btn,
.language-toggle-btn {
  display: grid;
  place-items: center;
}

.language-toggle-btn {
  position: relative;
}

.profile-btn {
  width: 64px;
  min-width: 64px;
  font-size: 0.82rem;
}

.language-toggle-btn,
.difficulty-toggle-btn,
.theme-toggle-btn {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  border: 1px solid color-mix(in srgb, var(--line) 90%, transparent);
  background: color-mix(in srgb, var(--panel-strong) 72%, var(--line));
}

.theme-toggle-btn {
  flex: 0 0 auto;
}

.difficulty-toggle-btn {
  flex: 0 0 auto;
}

.control-icon {
  width: 21px;
  height: 21px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.language-icon {
  width: 21px;
  height: 21px;
  transform: translate(-2px, -2px);
  transition: color 0.18s ease;
}

.language-code {
  position: absolute;
  right: 6px;
  bottom: 6px;
  font-size: 0.52rem;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
}

.language-code-pt {
  color: color-mix(in srgb, var(--muted) 85%, var(--ink));
}

.language-code-en {
  display: none;
  color: var(--accent);
}

.language-toggle-btn[data-language="en"] .language-code-pt {
  display: none;
}

.language-toggle-btn[data-language="en"] .language-code-en {
  display: block;
}

.language-toggle-btn[data-language="en"] .language-icon {
  color: var(--accent);
}

.difficulty-icon {
  display: inline-flex;
  align-items: flex-end;
  gap: 3px;
  height: 20px;
  color: var(--accent);
}

.difficulty-icon span {
  width: 4px;
  border-radius: 999px;
  background: currentColor;
  opacity: 0.28;
  transition: opacity 0.18s ease;
}

.difficulty-icon span:nth-child(1) {
  height: 8px;
}

.difficulty-icon span:nth-child(2) {
  height: 13px;
}

.difficulty-icon span:nth-child(3) {
  height: 18px;
}

.difficulty-toggle-btn[data-difficulty="easy"] .difficulty-icon span:nth-child(1),
.difficulty-toggle-btn[data-difficulty="medium"] .difficulty-icon span:nth-child(-n + 2),
.difficulty-toggle-btn[data-difficulty="hard"] .difficulty-icon span {
  opacity: 1;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.difficulty-toggle-btn[hidden] {
  display: none;
}

.theme-state-icon {
  width: 22px;
  height: 22px;
  color: var(--accent);
}

.theme-moon-icon {
  display: none;
}

html[data-theme="dark"] .theme-sun-icon {
  display: none;
}

html[data-theme="dark"] .theme-moon-icon {
  display: block;
}

.profile-btn.active {
  background: var(--accent-strong, var(--accent));
  color: #fff;
  box-shadow: 0 8px 18px rgba(29, 111, 95, 0.18);
}

.subtitle {
  margin: 0;
  max-width: 58ch;
  color: var(--muted);
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-width: 220px;
}

.dashboard,
.grid-two {
  display: grid;
  gap: 16px;
}

.dashboard {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-bottom: 22px;
}

.grid-two {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.card {
  padding: 22px;
}

.stat-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.stat-label {
  color: var(--muted);
  font-size: 0.92rem;
}

.question-panel {
  margin-bottom: 22px;
}

.question-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  margin-bottom: 18px;
  color: var(--muted);
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 7px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 700;
}

.question-text {
  margin: 0 0 24px;
  font-size: 1.02rem;
  line-height: 1.62;
  font-weight: 500;
  overflow-wrap: anywhere;
}

.text-block {
  margin: 0 0 12px;
}

.text-block:last-child {
  margin-bottom: 0;
}

.text-block-heading {
  margin-top: 16px;
  font-weight: 800;
  color: var(--ink);
}

.text-block-item {
  margin-left: 16px;
  padding-left: 12px;
  border-left: 3px solid color-mix(in srgb, var(--accent) 35%, transparent);
  color: color-mix(in srgb, var(--ink) 92%, var(--muted));
}

.answer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

button {
  border: 0;
  border-radius: 14px;
  cursor: pointer;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background-color 0.18s ease;
}

button:focus-visible,
.question-text:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

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

button:disabled {
  cursor: not-allowed;
  opacity: 0.65;
}

.answer-btn,
.primary-btn,
.secondary-btn,
.danger-btn {
  padding: 14px 16px;
  font-size: 0.98rem;
}

.answer-btn {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  text-align: left;
  background: var(--panel-strong);
  border: 1px solid var(--line);
  color: var(--ink);
}

.answer-letter {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: color-mix(in srgb, var(--line) 52%, var(--panel-strong));
  color: var(--ink);
  font-weight: 800;
}

.answer-label {
  min-width: 0;
  line-height: 1.5;
  overflow-wrap: anywhere;
}

.answer-btn:hover:not(:disabled) {
  box-shadow: 0 10px 25px rgba(31, 42, 46, 0.08);
}

.answer-btn.correct {
  background: var(--success-soft);
  border-color: rgba(32, 98, 70, 0.35);
  color: var(--success);
}

.answer-btn.incorrect {
  background: var(--danger-soft);
  border-color: rgba(168, 68, 50, 0.35);
  color: var(--danger);
}

.primary-btn {
  background: var(--accent);
  color: #fff;
}

.secondary-btn {
  background: color-mix(in srgb, var(--panel-strong) 78%, var(--line));
  color: var(--ink);
}

.danger-btn {
  background: var(--danger-action);
  color: #fff;
}

.question-actions {
  display: flex;
  justify-content: flex-end;
  margin-top: 22px;
}

.feedback-box {
  margin-top: 18px;
  padding: 14px 16px;
  border-radius: 14px;
  line-height: 1.55;
  border: 1px solid transparent;
}

.feedback-box.success {
  background: var(--success-soft);
  color: var(--success);
  border-color: rgba(32, 98, 70, 0.3);
}

.feedback-box.error {
  background: var(--danger-soft);
  color: var(--danger);
  border-color: rgba(168, 68, 50, 0.3);
}

.hidden {
  display: none;
}

.summary-list {
  margin: 0;
}

.summary-list div {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 0;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
}

.summary-list div:last-child {
  border-bottom: 0;
}

.summary-list dt {
  color: var(--muted);
}

.summary-list dd {
  margin: 0;
  font-weight: 700;
}

@media (max-width: 840px) {
  .hero,
  .dashboard,
  .grid-two,
  .answer-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    flex-direction: column;
  }

  .hero-actions {
    min-width: auto;
  }
}

@media (max-width: 520px) {
  .app-shell {
    width: min(100% - 20px, 960px);
    margin: 16px auto 32px;
  }

  .hero,
  .card {
    border-radius: 14px;
  }

  .hero,
  .card {
    padding: 18px;
  }

  .question-meta {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
  }

  .answer-btn,
  .primary-btn,
  .secondary-btn,
  .danger-btn {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .switch-row {
    justify-content: center;
    gap: 4px;
  }

  .mode-controls {
    gap: 4px;
  }
}

@media (max-width: 360px) {
  .app-shell {
    width: min(100% - 14px, 960px);
  }

  .switch-row {
    width: calc(100% + 36px);
    margin-inline: -18px;
  }
}