/* ==========================================================================
   tokens.css — Single source of truth for all design tokens
   Shared across index.html, blog/blog.css, and blog/index.html.
   ========================================================================== */

/* === Self-hosted Inter font (eliminates render-blocking Google Fonts CSS) === */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/inter/v18/UcCO3FwrK3iLTeHuS_nVMrMxCp50SjIw2boKoduKmMEVuLyfAZ9hiA.woff2) format('woff2');
}
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/inter/v18/UcCO3FwrK3iLTeHuS_nVMrMxCp50SjIw2boKoduKmMEVuI2fAZ9hiA.woff2) format('woff2');
}
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/inter/v18/UcCO3FwrK3iLTeHuS_nVMrMxCp50SjIw2boKoduKmMEVuGKYAZ9hiA.woff2) format('woff2');
}
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/inter/v18/UcCO3FwrK3iLTeHuS_nVMrMxCp50SjIw2boKoduKmMEVuFuYAZ9hiA.woff2) format('woff2');
}

/* === Self-hosted JetBrains Mono (display font for headings, labels, metrics) === */
@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/jetbrainsmono/v18/tDbY2o-flEEny0FZhsfKu5WU4zr3E_BX0PnT8RD8yKxjPVmUsaaDhw.woff2) format('woff2');
}
@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url(https://fonts.gstatic.com/s/jetbrainsmono/v18/tDbY2o-flEEny0FZhsfKu5WU4zr3E_BX0PnT8RD8yKxjDFaUsaaDhw.woff2) format('woff2');
}

/* === Design Tokens (Light Mode — default) === */
:root {
  --color-bg: #f5f7f6;
  --color-bg-alt: #edf0ee;
  --color-bg-elevated: #e4e8e5;
  --color-bg-card: #f9faf9;
  --color-surface: #e4e8e5;
  --color-border: #d4d9d6;
  --color-border-hover: #c2c9c5;
  --color-text-primary: #1a2e22;
  --color-text-secondary: #3d5347;
  /* Fixed contrast: was #5e7568 (fails WCAG AA), now #4a6358 (passes 4.5:1) */
  --color-text-tertiary: #4a6358;
  --color-accent: #0d9488;
  --color-accent-dim: rgba(13, 148, 136, 0.06);
  --color-accent-border: rgba(13, 148, 136, 0.15);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'JetBrains Mono', 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', 'JetBrains Mono', Consolas, monospace;
  --content-width: 720px;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  --space-5xl: 8rem;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* === Dark Mode (system preference) === */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f1a14;
    --color-bg-alt: #162019;
    --color-bg-elevated: #1d2b22;
    --color-bg-card: #162019;
    --color-surface: #1d2b22;
    --color-border: #2a3d30;
    --color-border-hover: #3a5040;
    --color-text-primary: #e4e8e5;
    --color-text-secondary: #b0c0b6;
    --color-text-tertiary: #7d9488;
    --color-accent: #2dd4bf;
    --color-accent-light: #0f3d38;
    --color-accent-dim: rgba(45,212,191,0.08);
    --color-accent-border: rgba(45,212,191,0.2);
  }
}

/* === Dark Mode (manual toggle) === */
[data-theme="dark"] {
  --color-bg: #0f1a14;
  --color-bg-alt: #162019;
  --color-bg-elevated: #1d2b22;
  --color-bg-card: #162019;
  --color-surface: #1d2b22;
  --color-border: #2a3d30;
  --color-border-hover: #3a5040;
  --color-text-primary: #e4e8e5;
  --color-text-secondary: #b0c0b6;
  --color-text-tertiary: #7d9488;
  --color-accent: #2dd4bf;
  --color-accent-light: #0f3d38;
  --color-accent-dim: rgba(45,212,191,0.08);
  --color-accent-border: rgba(45,212,191,0.2);
}
[data-theme="light"] {
  --color-bg: #f5f7f6;
  --color-bg-alt: #edf0ee;
  --color-bg-elevated: #e4e8e5;
  --color-bg-card: #f9faf9;
  --color-surface: #e4e8e5;
  --color-border: #d4d9d6;
  --color-border-hover: #c2c9c5;
  --color-text-primary: #1a2e22;
  --color-text-secondary: #3d5347;
  --color-text-tertiary: #4a6358;
  --color-accent: #0d9488;
  --color-accent-light: #ccfbf1;
  --color-accent-dim: rgba(13,148,136,0.06);
  --color-accent-border: rgba(13,148,136,0.15);
}

/* === Theme Toggle Button === */
.theme-toggle { background: none; border: 1px solid var(--color-border); border-radius: var(--radius-sm); padding: 0.4rem; cursor: pointer; color: var(--color-text-secondary); display: flex; align-items: center; justify-content: center; transition: border-color var(--transition-fast), color var(--transition-fast); }
.theme-toggle:hover { border-color: var(--color-accent); color: var(--color-accent); }
.theme-toggle:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 2px; }
/* Icon visibility: default (no data-theme) follows system preference */
[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }
:root:not([data-theme]) .icon-sun { display: none; }
:root:not([data-theme]) .icon-moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) .icon-sun { display: block; }
  :root:not([data-theme]) .icon-moon { display: none; }
}