/* css/style.css */
:root {
  --color-bg: #ffffff;
  --color-text: #1a1a2e;
  --color-muted: #5a6472;
  --color-border: #e2e5e9;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-success: #16a34a;
  --color-danger: #dc2626;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.5;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  border-bottom: 1px solid var(--color-border);
  flex-wrap: wrap;
  gap: 1rem;
}

.site-header h1 { font-size: 1.1rem; margin: 0; }

#nav { display: flex; gap: 1.25rem; flex-wrap: wrap; }

#nav a { color: var(--color-muted); text-decoration: none; font-weight: 500; }

#nav a.active, #nav a:hover { color: var(--color-primary); }

#app-content { max-width: 960px; margin: 0 auto; padding: 2rem; min-height: 60vh; }

.site-footer {
  text-align: center;
  color: var(--color-muted);
  font-size: 0.85rem;
  padding: 1.5rem;
  border-top: 1px solid var(--color-border);
}

button {
  font: inherit;
  cursor: pointer;
  border-radius: 6px;
  border: 1px solid var(--color-border);
  background: var(--color-primary);
  color: #fff;
  padding: 0.5rem 1rem;
}

button:hover { background: var(--color-primary-dark); }

button.secondary { background: #fff; color: var(--color-text); }

button.secondary:hover { background: #f3f4f6; }

button:disabled { opacity: 0.6; cursor: not-allowed; }

.domain-list { list-style: none; padding: 0; }

.domain-list li { padding: 0.5rem 0; border-bottom: 1px solid var(--color-border); }

.study-section { margin-bottom: 2rem; }

.study-topic { margin-left: 1rem; padding-left: 1rem; border-left: 3px solid var(--color-border); margin-bottom: 1rem; }

.study-topic h4 { margin-bottom: 0.25rem; }

.quiz-option { display: block; margin: 0.5rem 0; }

.quiz-progress { color: var(--color-muted); }

.feedback-correct { color: var(--color-success); }

.feedback-incorrect { color: var(--color-danger); }

.quiz-score { font-size: 1.25rem; font-weight: 600; }

.flashcard {
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 3rem 2rem;
  text-align: center;
  min-height: 8rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.5rem;
}

.flashcard-service { color: var(--color-muted); font-size: 0.9rem; text-transform: uppercase; letter-spacing: 0.05em; }

.flashcard-text { font-size: 1.1rem; }

.flashcard-controls { display: flex; gap: 0.75rem; margin-top: 1rem; flex-wrap: wrap; }

.exam-header { display: flex; justify-content: space-between; margin-bottom: 1rem; font-weight: 600; }

.exam-timer { font-variant-numeric: tabular-nums; }

.exam-nav { display: flex; gap: 0.75rem; margin-top: 1rem; }

.review-item { border-left: 3px solid var(--color-border); padding-left: 1rem; margin-bottom: 1rem; }

.history-table { width: 100%; border-collapse: collapse; margin-bottom: 1.5rem; }

.history-table th, .history-table td { text-align: left; padding: 0.5rem; border-bottom: 1px solid var(--color-border); }