/* === Reset === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; }
body { line-height: 1.6; -webkit-font-smoothing: antialiased; }
img, svg { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; }
table { border-collapse: collapse; width: 100%; }

/* === Variables === */
:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --success: #16a34a;
  --success-light: #f0fdf4;
  --danger: #dc2626;
  --danger-light: #fef2f2;
  --warning: #ea580c;
  --warning-light: #fff7ed;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
}

body {
  font-family: var(--font);
  color: var(--gray-800);
  background: #fff;
}

/* === Typography === */
h1 { font-size: 1.875rem; font-weight: 700; line-height: 1.2; }
h2 { font-size: 1.5rem; font-weight: 600; line-height: 1.3; }
h3 { font-size: 1.25rem; font-weight: 600; line-height: 1.4; }
h4 { font-size: 1.125rem; font-weight: 600; }
small, .text-sm { font-size: 0.875rem; }
.text-xs { font-size: 0.75rem; }
.text-muted { color: var(--gray-500); }
.text-center { text-align: center; }
.text-right { text-align: right; }
.font-mono { font-family: var(--font-mono); }

/* === Spacing === */
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.mt-6 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mb-6 { margin-bottom: 2rem; }
.gap-2 { gap: 0.5rem; }
.gap-3 { gap: 1rem; }

/* === Layout === */
.container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1rem;
}
.container-sm { max-width: 640px; margin: 0 auto; padding: 0 1rem; }
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.grid { display: grid; }
.hidden { display: none !important; }

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  font-size: 0.9375rem;
  font-weight: 500;
  line-height: 1;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, box-shadow 0.15s;
  text-decoration: none;
  white-space: nowrap;
}
.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
.btn-primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.btn-primary:hover:not(:disabled) {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
}
.btn-outline {
  background: #fff;
  color: var(--gray-700);
  border-color: var(--gray-300);
}
.btn-outline:hover:not(:disabled) {
  background: var(--gray-50);
  border-color: var(--gray-400);
}
.btn-danger {
  background: var(--danger);
  color: #fff;
  border-color: var(--danger);
}
.btn-danger:hover:not(:disabled) {
  background: #b91c1c;
}
.btn-success {
  background: var(--success);
  color: #fff;
}
.btn-success:hover:not(:disabled) {
  background: #15803d;
}
.btn-sm { padding: 0.375rem 0.75rem; font-size: 0.8125rem; }
.btn-lg { padding: 0.875rem 1.75rem; font-size: 1.0625rem; }
.btn-block { width: 100%; }

/* === Forms === */
.form-group {
  margin-bottom: 1rem;
}
.form-group label {
  display: block;
  margin-bottom: 0.375rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--gray-700);
}
.form-input,
.form-select {
  width: 100%;
  padding: 0.625rem 0.75rem;
  font-size: 0.9375rem;
  border: 1px solid var(--gray-300);
  border-radius: var(--radius);
  background: #fff;
  color: var(--gray-800);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}
.form-input::placeholder { color: var(--gray-400); }
.form-help {
  font-size: 0.8125rem;
  color: var(--gray-500);
  margin-top: 0.25rem;
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
@media (max-width: 480px) {
  .form-row { grid-template-columns: 1fr; }
}

/* === Cards === */
.card {
  background: #fff;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}
.card-header {
  padding-bottom: 1rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--gray-100);
}

/* === Tables === */
.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
table {
  font-size: 0.875rem;
}
th {
  text-align: left;
  font-weight: 600;
  color: var(--gray-600);
  padding: 0.75rem;
  border-bottom: 2px solid var(--gray-200);
  white-space: nowrap;
}
td {
  padding: 0.75rem;
  border-bottom: 1px solid var(--gray-100);
  vertical-align: middle;
}
tr:hover td {
  background: var(--gray-50);
}

/* === Badges === */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.6rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 9999px;
  line-height: 1.4;
}
.badge-success { background: var(--success-light); color: var(--success); }
.badge-danger { background: var(--danger-light); color: var(--danger); }
.badge-warning { background: var(--warning-light); color: var(--warning); }
.badge-primary { background: var(--primary-light); color: var(--primary); }

/* === Spinner === */
.spinner {
  display: inline-block;
  width: 1.5rem;
  height: 1.5rem;
  border: 3px solid var(--gray-200);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
.spinner-sm { width: 1rem; height: 1rem; border-width: 2px; }
@keyframes spin { to { transform: rotate(360deg); } }

.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 3rem 1rem;
  gap: 1rem;
  color: var(--gray-500);
}

/* === Alert === */
.alert {
  padding: 0.875rem 1rem;
  border-radius: var(--radius);
  font-size: 0.875rem;
  margin-bottom: 1rem;
}
.alert-error {
  background: var(--danger-light);
  color: var(--danger);
  border: 1px solid #fecaca;
}
.alert-success {
  background: var(--success-light);
  color: var(--success);
  border: 1px solid #bbf7d0;
}
.alert-info {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid #bfdbfe;
}

/* === Tabs === */
.tabs {
  display: flex;
  border-bottom: 2px solid var(--gray-200);
  gap: 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.tab {
  padding: 0.75rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--gray-500);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  white-space: nowrap;
  background: none;
  border-top: none;
  border-left: none;
  border-right: none;
}
.tab:hover { color: var(--gray-700); }
.tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

/* === Misc === */
.divider {
  border: none;
  border-top: 1px solid var(--gray-200);
  margin: 1.5rem 0;
}
.copy-btn {
  background: none;
  border: 1px solid var(--gray-300);
  border-radius: var(--radius);
  padding: 0.375rem 0.75rem;
  font-size: 0.8125rem;
  color: var(--gray-600);
  cursor: pointer;
}
.copy-btn:hover { background: var(--gray-50); }

/* === Responsive === */
@media (max-width: 768px) {
  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }
  .card { padding: 1rem; }
  .container { padding: 0 0.75rem; }
}