/* ==========================================================================
   Design tokens — white + engineering blue
   ========================================================================== */
:root {
  /* Surfaces */
  --bg: #f6f8fc;
  --bg-alt: #eef3fa;
  --surface: #ffffff;
  --surface-2: #f9fbfe;

  /* Ink */
  --ink: #0a1a33;          /* deep navy — primary text */
  --ink-2: #2c3e5c;        /* secondary headings */
  --muted: #607089;        /* supporting text */
  --faint: #95a3b8;        /* captions, disabled */

  /* Lines */
  --line: #e1e8f2;
  --line-strong: #c9d5e6;
  --grid: rgba(21, 86, 240, 0.06);

  /* Accent — engineering blue */
  --accent: #1556f0;
  --accent-strong: #0b3fc1;
  --accent-deep: #0a2a7a;
  --accent-soft: #eaf1ff;
  --accent-tint: #d4e2ff;
  --accent-glow: rgba(21, 86, 240, 0.18);

  /* Typography */
  --font-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "Cascadia Mono", Consolas, monospace;

  --fs-xs: 0.75rem;
  --fs-sm: 0.875rem;
  --fs-base: 1rem;
  --fs-md: 1.125rem;
  --fs-lg: 1.375rem;
  --fs-xl: 1.75rem;
  --fs-2xl: clamp(1.9rem, 1.4rem + 1.8vw, 2.6rem);
  --fs-3xl: clamp(2.3rem, 1.5rem + 3.4vw, 4rem);

  --lh-tight: 1.12;
  --lh-snug: 1.3;
  --lh-body: 1.6;

  /* Spacing (4px base) */
  --s-1: 4px;
  --s-2: 8px;
  --s-3: 12px;
  --s-4: 16px;
  --s-5: 24px;
  --s-6: 32px;
  --s-7: 48px;
  --s-8: 64px;
  --s-9: 96px;
  --s-10: 128px;

  /* Radius */
  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 16px;
  --r-pill: 999px;

  /* Elevation */
  --shadow-1: 0 1px 2px rgba(10, 26, 51, 0.05), 0 2px 8px rgba(10, 26, 51, 0.04);
  --shadow-2: 0 2px 4px rgba(10, 26, 51, 0.05), 0 12px 32px rgba(21, 56, 140, 0.10);
  --shadow-focus: 0 0 0 3px var(--accent-glow);

  /* Layout */
  --container: 1200px;
  --gutter: clamp(16px, 4vw, 40px);
  --nav-h: 68px;

  /* Motion */
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  --t-fast: 140ms;
  --t-med: 260ms;
  --t-slow: 520ms;
}