:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --success: #16a34a;
  --danger: #dc2626;
  --warning: #d97706;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-900: #111827;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,.12);
}

*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: var(--gray-900);
  background: var(--gray-50);
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Layout */
.container { max-width: 900px; margin: 0 auto; padding: 0 16px; }

.navbar {
  background: #fff;
  border-bottom: 1px solid var(--gray-200);
  padding: 12px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}
.navbar .inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.navbar .brand { font-weight: 700; font-size: 1.1rem; color: var(--gray-900); }
.navbar .nav-links { display: flex; gap: 16px; align-items: center; }

.page { padding: 32px 0; }

/* Cards */
.card {
  background: #fff;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}

/* Forms */
.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-weight: 500; margin-bottom: 4px; }
.form-group input {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  font-size: 1rem;
}
.form-group input:focus { outline: 2px solid var(--primary); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: background .15s;
  text-decoration: none;
}
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover:not(:disabled) { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-outline {
  background: transparent;
  border: 1px solid var(--gray-200);
  color: var(--gray-700);
}
.btn-outline:hover { background: var(--gray-100); }
.btn-sm { padding: 6px 12px; font-size: .875rem; }

/* Alerts */
.alert {
  padding: 12px 16px;
  border-radius: var(--radius);
  margin-bottom: 16px;
  font-size: .9rem;
}
.alert-error { background: #fef2f2; color: var(--danger); border: 1px solid #fecaca; }
.alert-success { background: #f0fdf4; color: var(--success); border: 1px solid #bbf7d0; }
.alert-info { background: #eff6ff; color: var(--primary); border: 1px solid #bfdbfe; }

/* Table */
table { width: 100%; border-collapse: collapse; }
th, td { padding: 10px 12px; text-align: left; border-bottom: 1px solid var(--gray-200); }
th { font-weight: 600; background: var(--gray-50); font-size: .875rem; }
tr:hover td { background: var(--gray-50); }

/* Badge */
.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 99px;
  font-size: .75rem;
  font-weight: 600;
}
.badge-green { background: #dcfce7; color: var(--success); }
.badge-red { background: #fef2f2; color: var(--danger); }
.badge-blue { background: #eff6ff; color: var(--primary); }
.badge-gray { background: var(--gray-100); color: var(--gray-600); }

/* Progress bar */
.progress-bar {
  height: 8px;
  background: var(--gray-200);
  border-radius: 99px;
  overflow: hidden;
}
.progress-bar .fill {
  height: 100%;
  background: var(--primary);
  border-radius: 99px;
  transition: width .3s;
}

/* Timer */
.timer {
  font-size: 1.5rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}
.timer.warning { color: var(--warning); }
.timer.danger { color: var(--danger); }

/* Answer options */
.answer-list { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 8px; }
.answer-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 16px;
  border: 2px solid var(--gray-200);
  border-radius: var(--radius);
  cursor: pointer;
  transition: border-color .15s, background .15s;
  background: #fff;
}
.answer-item:hover { border-color: var(--primary); background: #eff6ff; }
.answer-item.selected { border-color: var(--primary); background: #eff6ff; }
.answer-item.correct { border-color: var(--success); background: #f0fdf4; }
.answer-item.wrong { border-color: var(--danger); background: #fef2f2; }
.answer-item input[type=radio] { margin-top: 3px; flex-shrink: 0; }

/* Utility */
.mt-0 { margin-top: 0; }
.mt-4 { margin-top: 16px; }
.mt-8 { margin-top: 32px; }
.mb-4 { margin-bottom: 16px; }
.text-center { text-align: center; }
.text-muted { color: var(--gray-600); }
.text-sm { font-size: .875rem; }
.flex { display: flex; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.gap-2 { gap: 8px; }
.gap-4 { gap: 16px; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 600px) { .grid-2 { grid-template-columns: 1fr; } }

[x-cloak] { display: none !important; }

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
}