/* improved.css */

/* == Tokens & Design System == */
:root {
  /* Colors */
  --color-bg: #ffffff;
  --color-text: #000000;
  --color-muted: #555555;
  --color-link: #005ab5;            /* ~7.5:1 contrast vs white; WCAG AAA */
  --color-link-hover: #003f7f;
  --color-link-visited: #4c4c99;
  --color-border: #e5e7eb;
  --color-code-bg: #f5f5f5;
  --color-code-text: #111111;
  --color-panel: rgba(127,127,127,0.06);

  /* Spacing scale (logical) */
  --space-0: 0.25rem;
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2rem;

  /* Radii */
  --radius-sm: 4px;
  --radius-md: 8px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 8px rgba(0,0,0,0.1);

  /* Motion */
  --duration: 180ms;
  --easing: ease-out;

  /* Content width */
  --content-max: 72rem; /* ~1152px */

  /* Type scale based on fluid motion */
  --type-scale-ratio: 1.25;
  --font-size-base: clamp(1rem, 1rem + 0.2vw, 1.125rem);
  --font-size-h1: clamp(2rem, 2rem + 1vw, 2.5rem);
  --font-size-h2: clamp(1.75rem, 1.75rem + 0.8vw, 2.25rem);
  --font-size-h3: clamp(1.5rem, 1.5rem + 0.6vw, 2rem);
}

/* Dark‑mode variants */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #ffffff; /* Keep white background */
    --color-text: #000000;
    --color-muted: #666666;
    --color-link: #003f7f;
    --color-link-hover: #002266;
    --color-link-visited: #333366;
    --color-border: #bbbbbb;
    --color-code-bg: #f0f0f0;
    --color-code-text: #111111;
    --color-panel: rgba(127,127,127,0.06);
  }
}

/* == Layered Resets and Base == */
@layer base {
  *, *::before, *::after {
    box-sizing: border-box;
  }

  html {
    scroll-behavior: smooth;
    font-size: var(--font-size-base);
  }

  body {
    margin: 0;
    font-family: 'Inter', system-ui, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
  }

  /* Open-source self-hosted fonts */
  @font-face {
    font-family: 'Inter';
    src: url('/fonts/Inter-Regular.woff2') format('woff2');
    font-weight: 400;
    font-display: swap;
  }
  @font-face {
    font-family: 'JetBrains Mono';
    src: url('/fonts/JetBrainsMono-Regular.woff2') format('woff2');
    font-weight: 400;
    font-display: swap;
  }
}

/* == Typography, Layout Container == */
@layer components {
  header, main, footer {
    max-inline-size: var(--content-max);
    margin-inline: auto;
    padding-block: var(--space-2);
    padding-inline: var(--space-2);
  }
  header {
    padding-block-start: var(--space-3);
  }

  h1 { font-size: var(--font-size-h1); line-height: 1.25; margin-block-end: var(--space-1); }
  h2 { font-size: var(--font-size-h2); line-height: 1.3; }
  h3 { font-size: var(--font-size-h3); line-height: 1.35; }

  p + p {
    margin-block-start: var(--space-1);
  }

  .tagline {
    color: var(--color-muted);
    margin-block-start: var(--space-0);
  }

  hr {
    margin-block: var(--space-3) 0;
    border: none;
    border-top: 1px solid var(--color-border);
  }

  /* Typography for code/blocks */
  code, pre, kbd, samp {
    font-family: 'JetBrains Mono', ui-monospace, monospace;
  }

  pre {
    background: var(--color-code-bg);
    color: var(--color-code-text);
    padding: var(--space-2);
    border-radius: var(--radius-md);
    overflow: auto;
    border: 1px solid var(--color-border);
  }
  pre code {
    background: transparent;
    padding: 0;
  }
  code {
    background: rgba(0,0,0,0.05);
    padding: 0.2em 0.4em;
    border-radius: var(--radius-sm);
  }

  blockquote {
    border-inline-start: 4px solid var(--color-border);
    padding-inline-start: var(--space-1);
    margin-inline-start: 0;
    color: var(--color-muted);
  }

  ul, ol {
    padding-inline-start: var(--space-2);
  }

  /* Skip-link, for keyboard users */
  .skip-link {
  position: absolute;
  top: 0;
  left: 0;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  border: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.skip-link:focus-visible {
  width: auto;
  height: auto;
  margin: 0;
  padding: var(--space-1) var(--space-2);
  background: var(--color-link);
  color: var(--color-bg);
  clip: auto;
  white-space: normal;
  z-index: 1000;
  outline: 3px solid var(--color-link);
  position: absolute;
  top: 0;
  left: 0;
}


/* == Link & Focus Styles == */
@layer utilities {
  a {
    color: var(--color-link);
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 2px;
  }
  a:hover, a:focus-visible {
    color: var(--color-link-hover);
    text-decoration-thickness: 2px;
    text-underline-offset: 3px;
  }
  a:visited {
    color: var(--color-link-visited);
  }

  :focus-visible {
    outline: 3px solid var(--color-link);
    outline-offset: 2px;
  }

  /* Ensure interactive elements meet 44×44px touch target */
  button, a, input, textarea, select {
    min-inline-size: 44px;
    min-block-size: 44px;
  }
}

/* == Accessibility & User Preferences == */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0 !important;
    transition-duration: 0 !important;
    scroll-behavior: auto !important;
  }
}

@media (forced-colors: active) {
  a {
    forced-color-adjust: none;
    color: HighlightText;
    background: Highlight;
  }
}

/* == Nav.toc and other preserved layout (minimal tweaks) == */
nav.toc {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding-block: var(--space-1);
  padding-inline: var(--space-2);
  margin-block: var(--space-2) var(--space-3);
  background: var(--color-panel);
}
nav.toc ul {
  margin: 0;
}
nav.toc li {
  margin-block: var(--space-0);
}

/* section scroll-margin */
.section {
  scroll-margin-block-start: 80px;
}

/* Footer (layout preserved, with logical props) */
footer {
  border-block-start: 1px solid var(--color-border);
  margin-block-start: var(--space-4);
  padding-block-start: var(--space-2);
  color: var(--color-muted);
}
footer .content-wrapper {
  display: flex;
  align-items: center;
  justify-content: center;
}
footer ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-2);
  padding: 0;
  margin-block-start: var(--space-1);
}
footer a {
  text-decoration: none;
  color: var(--color-link);
}
footer a:hover, footer a:focus-visible {
  text-decoration: underline;
}
@media (max-width: 768px) {
  footer ul {
    flex-direction: column;
    align-items: flex-start;
  }
  footer a {
    display: inline-block;
    padding-block: 0.35rem;
  }
}

/* == Print Styles == */
@media print {
  *,
  *::before,
  *::after {
    background: transparent !important;
    color: #000 !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }
  a {
    text-decoration: underline;
  }
  a::after {
    content: " (" attr(href) ")";
    font-size: 90%;
  }
}