/* ==========================================================================
   s0 base styles & typography
   ========================================================================== */

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

html {
  font-family: var(--font-sans);
  background-color: var(--surface-canvas);
  color: var(--text-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--surface-canvas);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 15px;
  overflow-x: clip;
}

/* Accessibility skip link */
.sr-only, .skip-link {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link:focus {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 10000;
  width: auto;
  height: auto;
  padding: 10px 16px;
  background: var(--surface-raised);
  color: var(--brand);
  border: 2px solid var(--border-focus);
  border-radius: var(--radius-sm);
  clip: auto;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

/* Layout container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

@media (max-width: 640px) {
  .container {
    padding-left: 16px;
    padding-right: 16px;
  }
}

/* Typography elements */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.2;
}

p {
  color: var(--text-secondary);
}

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

a:hover {
  color: var(--brand-hover);
  text-decoration: underline;
}

code, kbd, samp, pre {
  font-family: var(--font-mono);
}

code {
  font-size: 0.9em;
  padding: 0.15em 0.35em;
  background-color: var(--surface-sunken);
  border: 1px solid var(--border-subtle);
  border-radius: 4px;
  color: var(--text-primary);
}

pre {
  background-color: var(--surface-sunken);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 16px;
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.6;
}

pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: inherit;
}

/* Focus rings */
:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}