:root {
  color-scheme: light dark;
  --font-body: "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont,
    "Helvetica Neue", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 30px 60px rgba(15, 23, 42, 0.15);
  --container-max: 1100px;
  --container-wide: 1200px;
  --space-2: 0.5rem;
  --space-4: 1rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --transition-fast: 150ms ease;
  --transition-slow: 320ms ease;
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0ms;
    --transition-slow: 0ms;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

html.theme-light {
  --color-bg: #ffffff;
  --color-bg-elevated: #f6f9fc;
  --color-bg-hero: linear-gradient(
    135deg,
    #eef2ff 0%,
    #f4f8ff 45%,
    #ffffff 100%
  );
  --color-surface: #ffffff;
  --color-border: rgba(15, 23, 42, 0.08);
  --color-text: #0f172a;
  --color-text-muted: #465471;
  --color-text-inverse: #ffffff;
  --color-accent: #2653ff;
  --color-accent-strong: #1833b8;
  --color-accent-soft: rgba(38, 83, 255, 0.12);
  --color-highlight: #0ea5e9;
}

html.theme-dark {
  --color-bg: #0f172a;
  --color-bg-elevated: #111a32;
  --color-bg-hero: linear-gradient(
    135deg,
    #0f172a 0%,
    #1e293b 60%,
    #111827 100%
  );
  --color-surface: #161f36;
  --color-border: rgba(226, 232, 240, 0.12);
  --color-text: #e2e8f0;
  --color-text-muted: #cdd5e1;
  --color-text-inverse: #0f172a;
  --color-accent: #60a5fa;
  --color-accent-strong: #3b82f6;
  --color-accent-soft: rgba(96, 165, 250, 0.16);
  --color-highlight: #38bdf8;
}

/* Auto dark mode support */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f172a;
    --color-bg-elevated: #111a32;
    --color-bg-hero: linear-gradient(
      135deg,
      #0f172a 0%,
      #1e293b 60%,
      #111827 100%
    );
    --color-surface: #161f36;
    --color-border: rgba(226, 232, 240, 0.12);
    --color-text: #e2e8f0;
    --color-text-muted: #cdd5e1;
    --color-text-inverse: #0f172a;
    --color-accent: #60a5fa;
    --color-accent-strong: #3b82f6;
    --color-accent-soft: rgba(96, 165, 250, 0.16);
    --color-highlight: #38bdf8;
  }
}

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

body {
  margin: var(--space-4);
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  transition: background var(--transition-slow), color var(--transition-slow);
  -webkit-font-smoothing: antialiased;
}

[hidden] {
  display: none !important;
}

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

/* Focus visible styles for better accessibility */
*:focus {
  outline: 2px solid transparent;
  outline-offset: 2px;
}

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

button:focus-visible,
a:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-fast), opacity var(--transition-fast);
}

a:hover,
a:focus {
  color: var(--color-accent-strong);
}

main a {
  text-decoration: underline;
  text-decoration-color: rgba(38, 83, 255, 0.35);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

main a:hover {
  text-decoration-color: var(--color-accent);
}

::selection {
  background: var(--color-highlight);
  color: var(--color-text-inverse);
}

h1,
h2,
h3,
h4 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text);
  margin: 0 0 var(--space-4);
}

p {
  margin: 0 0 var(--space-4);
  color: var(--color-text-muted);
}

code,
pre {
  font-family: var(--font-mono);
  font-size: 0.95em;
  background: var(--color-bg-elevated);
  border-radius: var(--radius-sm);
}

code {
  padding: 0.2em 0.4em;
}

pre {
  padding: var(--space-4);
  overflow-x: auto;
  box-shadow: inset 0 0 0 1px var(--color-border);
}