:root {
  
  --color-canvas: oklch(0.15 0.02 255);

  
  --color-surface: oklch(0.20 0.02 255);

  
  --color-surface-elevated: oklch(0.24 0.025 255);

  
  --color-border: oklch(0.33 0.025 255);

  
  --color-text-primary: oklch(0.95 0.01 255);

  
  --color-text-secondary: oklch(0.82 0.015 255);

  
  --color-text-muted: oklch(0.72 0.02 255);

  
  --color-accent: oklch(0.72 0.16 55);
  --color-accent-hover: oklch(0.77 0.15 55);

  
  --color-accent-secondary: oklch(0.78 0.12 205);

  
  --color-on-accent: oklch(0.16 0.02 255);

  
  --color-accent-soft: oklch(0.72 0.16 55 / 0.10);
  --color-accent-soft-strong: oklch(0.72 0.16 55 / 0.18);
  --color-accent-glow: oklch(0.72 0.16 55 / 0.38);
  --color-overlay-soft: oklch(1 0 0 / 0.025);
  --color-shadow: oklch(0 0 0 / 0.46);
  --color-shadow-soft: oklch(0 0 0 / 0.34);

  
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: "Fira Code", "Courier New", Courier, monospace;

  
  --font-size-xs: 0.8rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-md: 1.05rem;
  --font-size-lg: 1.15rem;
  --font-size-xl: 1.25rem;
  --line-height-compact: 1.3;
  --line-height-base: 1.6;
  --line-height-relaxed: 1.7;

  
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 2.5rem;
  --space-3xl: 3rem;

  
  --radius-xs: 0.25rem;
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-pill: 999px;

  
  --layout-max-width: 75rem;
  --sidebar-ratio: 2.7fr;
  --content-ratio: 7.3fr;

  
  --timeline-number-column: 1.25rem;
  --timeline-date-column: minmax(16rem, 20rem);

  --control-height: 2.75rem;
  --control-height-primary: 3rem;
  --border-hairline: 1px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --focus-ring: 0 0 0 0.25rem var(--color-accent-secondary);
  --shadow-card: 0 var(--space-sm) var(--space-xl) var(--color-shadow-soft);
  --shadow-header: 0 var(--space-lg) var(--space-2xl) var(--color-shadow);
}

[data-theme="light"] {
  --color-canvas: oklch(0.97 0.008 255);
  --color-surface: oklch(0.995 0.002 255);
  --color-surface-elevated: oklch(0.965 0.01 255);
  --color-border: oklch(0.86 0.02 255);
  --color-text-primary: oklch(0.22 0.025 255);
  --color-text-secondary: oklch(0.36 0.025 255);
  --color-text-muted: oklch(0.45 0.025 255);
  --color-accent: oklch(0.52 0.125 55);
  --color-accent-hover: oklch(0.46 0.11 55);
  --color-accent-secondary: oklch(0.45 0.07 205);
  --color-on-accent: oklch(0.995 0.002 255);
  --color-accent-soft: oklch(0.52 0.125 55 / 0.09);
  --color-accent-soft-strong: oklch(0.52 0.125 55 / 0.15);
  --color-accent-glow: oklch(0.52 0.125 55 / 0.24);
  --color-overlay-soft: oklch(0.22 0.025 255 / 0.025);
  --color-shadow: oklch(0.22 0.025 255 / 0.16);
  --color-shadow-soft: oklch(0.22 0.025 255 / 0.10);
}

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

html {
  color-scheme: dark;
  scroll-behavior: smooth;
}

[data-theme="light"] {
  color-scheme: light;
}

body {
  margin: 0;
  padding: 0;

  
  background-color: var(--color-canvas);

  
  color: var(--color-text-primary);

  
  font-family: var(--font-sans);

  
  line-height: var(--line-height-base);

  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition:
    background-color var(--transition-normal),
    color var(--transition-normal);
}

.skip-link {
  position: fixed;

  
  top: var(--space-xs);
  left: var(--space-xs);
  transform: translateY(calc(-100% - var(--space-lg)));

  
  background: var(--color-accent);

  
  color: var(--color-on-accent);

  
  padding: var(--space-sm) var(--space-md);

  min-height: var(--control-height);
  display: inline-flex;
  align-items: center;
  font-weight: 700;
  z-index: 1000;

  
  transition: transform var(--transition-fast);

  text-decoration: none;

  
  border-radius: var(--radius-sm);
}

.skip-link:focus {
  
  transform: translateY(0);
}

:where(a, button):focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}

.theme-toggle {
  min-height: var(--control-height);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  border: var(--border-hairline) solid var(--color-border);
  font: inherit;
  font-size: var(--font-size-sm);
  font-weight: 700;
  cursor: pointer;
  text-decoration: none;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    color var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast);
}

.theme-toggle {
  color: var(--color-text-primary);
  background-color: var(--color-surface);
}

.theme-toggle:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

@supports (text-box: trim-both cap alphabetic) {
  .theme-toggle {
    text-box: trim-both cap alphabetic;
    padding-block: calc(var(--space-sm) + 0.15em);
  }
}