/* =============================
   Global Theme Variables
   ============================= */
:root {
  --bg: #f3f4f6;               /* page background */
  --primary: #2563eb;          /* primary action blue (Tailwind blue‑600) */
  --primary-dark: #1e40af;     /* darker blue for hover / emphasis */
  --white: #ffffff;
  --text: #111827;             /* gray‑900 */
  --muted: #6b7280;            /* gray‑500 */
  --card-bg: #ffffff;
  --border: #e5e7eb;           /* gray‑200 */
  --shadow: 0 4px 6px rgba(0,0,0,0.05);
  --radius: 8px;
  --transition: 0.25s ease;
}

/* =============================
   Reset & Base
   ============================= */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container {
  max-width: 1200px;
  margin: auto;
  padding: 2rem 1.25rem;
}

h1 {
  text-align: center;
  color: var(--text);
  margin-bottom: 2rem;
  font-size: clamp(1.75rem, 2vw + 1rem, 2.25rem);
}

/* =============================
   Language Tabs
   ============================= */
.lang-tab {
  display: flex;
  align-items: center;
  gap: 1rem;
  border-bottom: 1px solid var(--border);
  background: var(--white);
  padding: 0.5rem 1rem;
  box-shadow: var(--shadow);
  border-radius: var(--radius) var(--radius) 0 0;
}

.lang-tab .lang-tablinks {
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  color: var(--text);
  border-bottom: 3px solid transparent;
  transition: var(--transition);
}

.lang-tab .lang-tablinks:hover {
  background: rgba(37, 99, 235, 0.08); /* light primary tint */
}

.lang-tab .lang-tablinks.active {
  font-weight: 600;
  color: var(--primary);
  border-bottom-color: var(--primary);
}

/* Expand / Collapse Buttons */
.expand-collapse-buttons {
  margin-left: auto;
  display: flex;
  gap: 0.75rem;
}

.control-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  background: var(--primary);
  color: var(--white);
  border: none;
  border-radius: var(--radius);
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  cursor: pointer;
  transition: var(--transition);
}

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

/* =============================
   Category Tabs
   ============================= */
.category-tab {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1rem;
}

.category-tab button {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius) var(--radius) 0 0;
  padding: 0.5rem 0.875rem;
  font-size: 0.9375rem;
  color: var(--muted);
  cursor: pointer;
  transition: var(--transition);
}

.category-tab button:hover {
  background: rgba(107, 114, 128, 0.08); /* muted tint */
}

.category-tab button.active {
  background: var(--white);
  color: var(--primary);
  font-weight: 600;
  border-bottom-color: var(--white);
}

/* =============================
   Questions & Answers
   ============================= */
.question-block {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1.5rem;
  overflow: hidden;
  transition: var(--transition);
}

.question-title {
  font-size: 1.25rem;
  color: var(--primary-dark);
  padding: 1rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.question-title::after {
  content: "\25BC"; /* down chevron */
  font-size: 0.85rem;
  transition: transform var(--transition);
}

.question-block.active .question-title::after {
  transform: rotate(180deg);
}

.answers-container {
  display: none;
  flex-wrap: wrap;
  gap: 1.25rem;
  padding: 1rem 1.25rem 1.5rem;
}

.question-block.active .answers-container {
  display: flex;
}

.answer-card {
  flex: 1 1 300px;
  background: #fafafa;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  box-shadow: var(--shadow);
  transition: transform var(--transition);
}

.answer-card:hover {
  transform: translateY(-2px);
}

.answer-card h4 {
  margin-bottom: 0.75rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  border-bottom: 2px solid var(--primary);
  padding-bottom: 0.5rem;
}

.correct { color: #16a34a; }  /* green‑600 */
.incorrect { color: #dc2626; } /* red‑600 */

.markdown-content {
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--text);
}

.markdown-content * {
  max-width: 100%;
}

/* =============================
   Responsive
   ============================= */
@media (max-width: 900px) {
  .answers-container { flex-direction: column; }
  .answer-card { width: 100%; }
}