:root {
  /* 1.1 Colour — brand */
  --color-accent-50: #F3F8FF;
  --color-accent-100: #E7F0FE;
  --color-accent-200: #C9DEFE;
  --color-accent-300: #9CC2FD;
  --color-accent: #589BFC;
  --color-accent-hover: #3A85F4;
  --color-accent-strong: #1F6FE0;
  --color-accent-strong-hover: #1A61C6;
  --color-accent-pressed: #1758B4;
  --color-accent-ring: rgba(31,111,224,0.35);
  --color-on-accent: #FFFFFF;

  /* 1.2 Colour — neutrals & surfaces */
  --color-ink: #333335;
  --color-ink-muted: #67676B;
  --color-ink-soft: #838385;
  --color-ink-disabled: #A2A2A6;
  --color-bg: #F0F2F6;
  --color-surface: rgba(255,255,255,0.65);
  --color-surface-hover: rgba(255,255,255,0.85);
  --color-surface-solid: #FFFFFF;
  --color-surface-inset: rgba(240,242,246,0.65);
  --color-surface-inset-solid: #F0F2F6;
  --color-surface-sunken: #E6E9F0;
  --color-border: #E8E8E8;
  --color-border-glass: rgba(255,255,255,0.60);
  --color-border-strong: #D3D6DE;
  --color-overlay: rgba(51,51,53,0.45);

  /* 1.3 Colour — semantic */
  --color-success: #00C171;
  --color-success-subtle: #E3F7EF;
  --color-success-ink: #036B41;
  --color-warning: #FDAB3B;
  --color-warning-subtle: #FEF1DE;
  --color-warning-ink: #7A4A06;
  --color-danger: #FA4170;
  --color-danger-subtle: #FEE8EE;
  --color-danger-ink: #A80F3C;
  --color-violet: #6160FF;
  --color-violet-subtle: #EBEBFF;
  --color-violet-ink: #3E3DC7;
  --color-neutral-badge: var(--color-ink-soft);
  --color-neutral-badge-subtle: #E6E9F0;
  --color-neutral-badge-ink: var(--color-ink-muted);
  --color-danger-strong: #D11A4C;
  --color-danger-strong-hover: #B3143F;
  --color-success-strong: #047A48;

  /* 1.4 Typography */
  --font-sans: "Outfit", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --text-display: 48px;
  --text-display--line-height: 1.1;
  --text-2xl: 34px;
  --text-2xl--line-height: 1.15;
  --text-xl: 26px;
  --text-xl--line-height: 1.2;
  --text-lg: 20px;
  --text-lg--line-height: 1.3;
  --text-base: 16px;
  --text-base--line-height: 1.25;
  --text-sm: 14px;
  --text-sm--line-height: 1.4;
  --text-sm-light: 14px;
  --text-sm-light--line-height: 1.4;
  --text-xs: 12px;
  --text-xs--line-height: 1.35;
  --text-2xs: 11px;
  --text-2xs--line-height: 1.3;
  --numeric-tabular: tabular-nums;

  /* 1.5 Spacing */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;
  --space-20: 80px;

  /* 1.6 Radii */
  --radius-xs: 6px;
  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 999px;
  --radius-round: 50%;

  /* 1.7 Elevation & glass */
  --shadow-xs: 0 4px 20px rgba(65,93,114,0.03);
  --shadow-sm: 0 4px 20px rgba(65,93,114,0.06);
  --shadow-md: 0 8px 28px rgba(65,93,114,0.10);
  --shadow-lg: 0 24px 60px rgba(65,93,114,0.18);
  --glass-blur: 20px;
  --glass-blur-sm: 12px;

  /* 1.8 Borders & dividers */
  --border-hairline: 1px solid var(--color-border);
  --border-glass: 1px solid var(--color-border-glass);
  --border-selected: 2px solid var(--color-accent-strong);
  --border-dashed: 1.5px dashed var(--color-border-strong);

  /* 1.9 Motion */
  --duration-instant: 90ms;
  --duration-fast: 140ms;
  --duration-base: 200ms;
  --duration-slow: 300ms;
  --duration-spin: 800ms; /* FB-04 loading spinner rotation, referenced by F-01 Button */
  --duration-shimmer: 1400ms; /* DD-14 skeleton shimmer sweep, referenced by Ui::SkeletonComponent and its callers (DD-04, DD-08, DD-12 indeterminate) */
  --duration-highlight: 3000ms; /* CP-01 activity item new-since-last-visit wash fade, referenced by Ui::ActivityItemComponent */
  --ease-out: cubic-bezier(0.2, 0, 0, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-spring: cubic-bezier(0.34, 1.4, 0.64, 1);

  /* 1.10 Control sizes & z-index */
  --control-h-sm: 36px;
  --control-h: 44px;
  --control-h-lg: 52px;
  --icon-xs: 12px;
  --icon-sm: 16px;
  --icon-md: 20px;
  --icon-lg: 24px;
  --tap-min: 44px;
  --z-base: 0;
  --z-sticky: 100;
  --z-nav: 200;
  --z-popover: 400;
  --z-drawer: 600;
  --z-modal: 700;
  --z-toast: 900;

  /* 1.11 Breakpoints */
  --bp-sm: 480px;
  --bp-md: 768px;
  --bp-lg: 1024px;
  --bp-xl: 1280px;
  --bp-2xl: 1440px;

  /* Form column cap (spec §3.2, standing rule 4) — form cards never exceed
     this width. Applied via the .form-column utility in base.css. */
  --form-column: 640px;
}