/* ==========================================
   BASE.CSS — Resets, Typography & Base Element Styles
   ========================================== */

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

html {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-text);
  background-color: var(--color-bg);
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
  -webkit-text-size-adjust: 100%;
}

h1[id], h2[id], h3[id], section[id], div[id], main[id] {
  scroll-margin-top: 5.5rem;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image: linear-gradient(135deg, var(--color-bg) 0%, color-mix(in srgb, var(--seed-primary) 4%, var(--color-bg-alt)) 100%);
  background-attachment: fixed;
  transition: background-color var(--transition-med), color var(--transition-med);
}

/* Accessibility: Focus Indicators */
:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--color-primary);
  color: #ffffff;
  padding: 0.75rem 1.25rem;
  z-index: 9999;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 600;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 1rem;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-sm);
  padding-right: var(--space-sm);
}

@media (min-width: 768px) {
  .container {
    padding-left: var(--space-md);
    padding-right: var(--space-md);
  }
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  line-height: 1.15;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  font-weight: 400;
}

h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }

p {
  margin-bottom: var(--space-sm);
  max-width: 75ch; /* Optimum line length for readability */
}

p:last-child {
  margin-bottom: 0;
}

a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--transition-fast);
}

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

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

ul, ol {
  list-style-position: inside;
  margin-bottom: var(--space-sm);
}

/* Main landmark spacing */
main {
  flex: 1;
}

/* Utility Section Spacing */
.section {
  padding-top: var(--space-lg);
  padding-bottom: var(--space-lg);
}

.section-alt {
  background-color: var(--color-bg-alt);
}

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

.text-muted {
  color: var(--color-text-muted);
}