/* ==========================================================================
   Base Styles — Reset, Typography, Utilities, Accessibility
   ========================================================================== */

/* --- Reset --- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 100%;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-regular);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg {
  display: block;
  max-width: 100%;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  text-decoration: underline;
}

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

table {
  border-collapse: collapse;
  width: 100%;
}

/* --- Typography --- */
h1 {
  font-size: var(--font-size-h1);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
}

h2 {
  font-size: var(--font-size-h2);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
}

h3 {
  font-size: var(--font-size-h3);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-tight);
}

h4 {
  font-size: var(--font-size-h4);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-tight);
}

p, li, td, th {
  font-size: var(--font-size-body);
  line-height: var(--line-height-normal);
}

small {
  font-size: var(--font-size-small);
}

/* --- Accessibility: Focus Ring (Req 17.7) --- */
:focus-visible {
  outline: 3px solid var(--color-border-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Skip navigation link */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-4);
  padding: var(--space-2) var(--space-4);
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: var(--radius-sm);
  z-index: var(--z-toast);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-2);
}

/* --- Utility Classes --- */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.text-center { text-align: center; }
.text-right  { text-align: right; }

.flex       { display: flex; }
.flex-col   { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }

.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.p-2  { padding: var(--space-2); }
.p-4  { padding: var(--space-4); }

/* --- Transitions (max 300ms per Req 17.7) --- */
.transition {
  transition: all var(--transition-normal);
}