:root {
  --bg: #f7f6f3;
  --panel: #ffffff;
  --ink: #1f2320;
  --muted: #6b6f6a;
  --accent: #3f6f5e;
  --accent-ink: #ffffff;
  --border: #e3e1da;
  --good: #2f7a4f;
  --good-bg: #eaf6ee;
  --bad: #b3422f;
  --bad-bg: #fbeae7;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
}

header {
  max-width: 640px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 1rem;
  text-align: center;
}

h1 {
  margin: 0 0 0.25rem;
  font-size: 1.6rem;
  font-weight: 600;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

main {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 1.5rem 3rem;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  margin-top: 1.25rem;
}

.dropzone {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 140px;
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  color: var(--muted);
  cursor: pointer;
  text-align: center;
  padding: 1rem;
  transition: border-color 0.15s, background 0.15s;
}

.dropzone:hover, .dropzone.dragover {
  border-color: var(--accent);
  background: #f2f7f4;
}

.error {
  margin-top: 1rem;
  color: var(--bad);
  background: var(--bad-bg);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  font-size: 0.9rem;
}

h2 {
  margin-top: 0;
  font-size: 1.15rem;
}

.field {
  margin-bottom: 1rem;
}

.field label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.35rem;
}

.checkbox-field label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  color: var(--ink);
}

select {
  width: 100%;
  padding: 0.55rem 0.7rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--panel);
  font-size: 0.95rem;
  color: var(--ink);
}

button.primary {
  width: 100%;
  padding: 0.7rem 1rem;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: var(--accent-ink);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  margin-top: 0.5rem;
  transition: opacity 0.15s;
}

button.primary:hover { opacity: 0.9; }
button.primary:active { opacity: 0.8; }

.quiz-top {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.progress-bar {
  height: 6px;
  background: var(--border);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 1.25rem;
}

#progress-fill {
  height: 100%;
  background: var(--accent);
  width: 0%;
  transition: width 0.2s;
}

.tag {
  display: inline-block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--accent);
  background: #eaf1ee;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  margin-bottom: 0.6rem;
}

#q-text {
  font-size: 1.1rem;
  margin-bottom: 1.25rem;
}

#choices {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.choice {
  display: flex;
  gap: 0.6rem;
  align-items: flex-start;
  text-align: left;
  padding: 0.7rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel);
  cursor: pointer;
  font-size: 0.95rem;
  color: var(--ink);
  transition: border-color 0.15s, background 0.15s;
}

.choice:hover:not(:disabled) {
  border-color: var(--accent);
}

.choice:disabled {
  cursor: default;
}

.choice .letter {
  font-weight: 600;
  color: var(--muted);
  flex-shrink: 0;
}

.choice.correct {
  border-color: var(--good);
  background: var(--good-bg);
}

.choice.correct .letter { color: var(--good); }

.choice.incorrect {
  border-color: var(--bad);
  background: var(--bad-bg);
}

.choice.incorrect .letter { color: var(--bad); }

.explanation {
  margin-top: 1.1rem;
  padding: 0.9rem 1rem;
  background: #f5f4f0;
  border-radius: 8px;
  font-size: 0.9rem;
  color: var(--ink);
}

.explanation strong {
  display: block;
  margin-bottom: 0.3rem;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--muted);
}

.quiz-actions {
  margin-top: 1.25rem;
}

.results-summary {
  font-size: 1.4rem;
  font-weight: 600;
  margin: 0.25rem 0 1.25rem;
}

.results-breakdown {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
}

.breakdown-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
  padding: 0.4rem 0.6rem;
  border-radius: 6px;
  background: #f5f4f0;
}

.breakdown-row .subj { color: var(--ink); }
.breakdown-row .stat { color: var(--muted); }

footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.8rem;
  padding-bottom: 2rem;
}