:root {
  /* Color primitives */

  --color-neutral-0: oklch(100% 0 0);
  --color-neutral-50: oklch(98.4% 0 0);
  --color-neutral-100: oklch(96.8% 0 0);
  --color-neutral-150: oklch(93% 0.004 257);
  --color-neutral-200: oklch(92.9% 0 0);
  --color-neutral-300: oklch(86.9% 0 0);
  --color-neutral-400: oklch(70.4% 0 0);
  --color-neutral-500: oklch(55.4% 0 0);
  --color-neutral-600: oklch(44.6% 0 0);
  --color-neutral-700: oklch(34% 0.014 257);
  --color-neutral-800: oklch(26% 0.012 257);
  --color-neutral-900: oklch(20% 0.01 257);
  --color-neutral-950: oklch(14% 0.008 257);
  --color-neutral-1000: oklch(0% 0 0);

  /* Dark surface primitives: purpose-built for dark theme surface hierarchy.
     Consumers remap these to control dark theme surfaces independently of the
     light-mode neutral scale. */
  --color-neutral-dark-base: oklch(30% 0.012 257);
  --color-neutral-dark-subtle: oklch(36% 0.014 257);
  --color-neutral-dark-muted: oklch(38% 0.016 257);
  --color-neutral-dark-border: oklch(46% 0.016 257);
  --color-neutral-dark-input: oklch(26% 0.012 257);
  --color-neutral-dark-input-readonly: oklch(27% 0.012 257);

  /* Slate accent: hue 257, low chroma */
  --color-accent-100: oklch(96.8% 0.007 257);
  --color-accent-200: oklch(92.9% 0.013 257);
  --color-accent-300: oklch(86.9% 0.022 257);
  --color-accent-400: oklch(70.4% 0.04 257);
  --color-accent-460: oklch(60% 0.055 257);
  --color-accent-480: oklch(52% 0.05 257);
  --color-accent-500: oklch(44% 0.043 257);
  --color-accent-600: oklch(37.2% 0.044 257);
  --color-accent-700: oklch(27.9% 0.041 257);
  --color-accent-800: oklch(20.8% 0.042 257);

  /* Feedback color primitives: numeric scale per category.
     Steps 100-600: lightest to darkest, matching accent scale pattern.
     Light semantic tokens reference 100 (bg), 300 (base/border), 500 (text).
     Dark semantic tokens reference 200 (text), 300 (base), 400 (border), 600 (bg). */

  --color-success-100: oklch(94% 0.08 145);
  --color-success-200: oklch(75% 0.16 145);
  --color-success-250: oklch(58% 0.16 145);
  /* Dark-mode filled surface. n950-on: 5.04:1, passes AA. */
  --color-success-300: oklch(52% 0.18 145);
  --color-success-400: oklch(40% 0.14 145);
  --color-success-500: oklch(38% 0.16 145);
  --color-success-600: oklch(20% 0.06 145);

  --color-warning-100: oklch(95% 0.1 85);
  --color-warning-200: oklch(82% 0.18 85);
  --color-warning-300: oklch(72% 0.22 85);
  --color-warning-400: oklch(55% 0.18 85);
  --color-warning-500: oklch(48% 0.18 85);
  --color-warning-600: oklch(20% 0.06 85);

  --color-danger-100: oklch(95% 0.06 15);
  --color-danger-200: oklch(75% 0.18 15);
  --color-danger-250: oklch(60% 0.2 15);
  /* Dark-mode filled surface. n950-on: 4.59:1, passes AA. */
  --color-danger-300: oklch(56% 0.22 15);
  --color-danger-400: oklch(50% 0.18 15);
  --color-danger-500: oklch(42% 0.2 15);
  --color-danger-600: oklch(20% 0.05 15);

  --color-info-100: oklch(94% 0.06 230);
  --color-info-200: oklch(75% 0.16 230);
  --color-info-300: oklch(53% 0.18 230);
  /* Darkened from 55% for white-on contrast: 4.69:1, passes AA. */
  --color-info-400: oklch(48% 0.14 230);
  --color-info-500: oklch(40% 0.16 230);
  --color-info-600: oklch(18% 0.05 230);

  /* Space primitives */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Shadow primitives */
  --shadow-sm: 0 1px 3px oklch(0% 0 0 / 0.1), 0 1px 2px oklch(0% 0 0 / 0.06);
  --shadow-md: 0 4px 6px oklch(0% 0 0 / 0.1), 0 2px 4px oklch(0% 0 0 / 0.06);
  --shadow-lg: 0 10px 15px oklch(0% 0 0 / 0.1), 0 4px 6px oklch(0% 0 0 / 0.05);
  --shadow-sm-dark:
    0 1px 3px oklch(0% 0 0 / 0.4), 0 1px 2px oklch(0% 0 0 / 0.24);
  --shadow-md-dark:
    0 4px 6px oklch(0% 0 0 / 0.4), 0 2px 4px oklch(0% 0 0 / 0.24);
  --shadow-lg-dark:
    0 10px 15px oklch(0% 0 0 / 0.5), 0 4px 6px oklch(0% 0 0 / 0.3);

  /* Z-index primitives */
  --z-header: 10;
  --z-dropdown: 50;
  --z-modal: 100;
  --z-toast: 150;

  /* Radius primitives */
  --radius-none: 0;
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-full: 9999px;

  /* Duration primitives */
  --duration-fast: 100ms;
  --duration-base: 200ms;
  --duration-slow: 300ms;
  --duration-deliberate: 500ms;

  /* Typography primitives */
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-md: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;

  --line-height-tight: 1.25;
  --line-height-snug: 1.375;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;

  --font-weight-thin: 100;
  --font-weight-extralight: 200;
  --font-weight-light: 300;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;
  --font-weight-black: 900;

  --font-family-sans: ui-sans-serif, system-ui, -apple-system, sans-serif;
  --font-family-serif: ui-serif, Georgia, Cambria, serif;
  --font-family-mono: ui-monospace, "SFMono-Regular", Menlo, monospace;
}

/* Semantic tokens: light theme */
:root,
[data-theme="light"] {
  /* Surfaces */
  --nuka-bg-base: var(--color-neutral-0);
  --nuka-bg-subtle: var(--color-neutral-50);
  --nuka-bg-muted: var(--color-neutral-100);
  --nuka-bg-emphasis: var(--color-neutral-900);

  /* Borders */
  --nuka-border-base: var(--color-neutral-200);
  --nuka-border-strong: var(--color-neutral-400);
  --nuka-border-focus: var(--color-accent-500);

  /* Text */
  --nuka-text-base: var(--color-neutral-900);
  --nuka-text-muted: var(--color-neutral-600);
  --nuka-text-subtle: var(--color-neutral-400);
  --nuka-text-inverse: var(--color-neutral-0);
  --nuka-text-disabled: var(--color-neutral-300);

  /* Accent */
  --nuka-accent-bg: var(--color-accent-500);
  --nuka-accent-bg-hover: var(--color-accent-600);
  --nuka-accent-bg-active: var(--color-accent-700);
  --nuka-accent-bg-subtle: var(--color-accent-100);
  --nuka-accent-border: var(--color-accent-400);
  --nuka-accent-text: var(--color-accent-500);
  /*
   * NOTE: --nuka-accent-text uses accent-500 (#43546a) on neutral-0 (white).
   * Contrast: 7.74:1, passes AAA. Safe to use for any text size.
   */
  --nuka-accent-fg: var(--color-neutral-0);
  /* Foreground for content on --nuka-accent-bg. Override independently of
     --nuka-text-inverse when the accent color is customized. 7.74:1 on accent-500. */
  --nuka-accent-bg-disabled: var(--color-neutral-200);

  /* Borders */
  --nuka-border-disabled: var(--color-neutral-200);

  /* Shadows */
  --nuka-shadow-card: var(--shadow-sm);
  --nuka-shadow-overlay: var(--shadow-md);
  --nuka-shadow-modal: var(--shadow-lg);

  /* Z-index */
  --nuka-z-header: var(--z-header);
  --nuka-z-dropdown: var(--z-dropdown);
  --nuka-z-modal: var(--z-modal);
  --nuka-z-toast: var(--z-toast);

  /* Font family */
  --nuka-font-heading: var(--font-family-serif);
  --nuka-font-body: var(--font-family-sans);
  --nuka-font-ui: var(--font-family-sans);
  --nuka-font-code: var(--font-family-mono);

  /* Overlay */
  /* No matching primitive: alpha-composite value, not a scale step.
     0.5 opacity is intentional for both themes. Consumer-overridable
     if dark mode needs higher opacity for visual weight. */
  --nuka-bg-overlay: oklch(0% 0 0 / 0.5);

  /* Duration */
  --nuka-duration-fast: var(--duration-fast);
  --nuka-duration-base: var(--duration-base);
  --nuka-duration-slow: var(--duration-slow);
  --nuka-duration-deliberate: var(--duration-deliberate);

  /* Input surfaces */
  --nuka-input-bg: var(--color-neutral-0);
  --nuka-input-bg-disabled: var(--color-neutral-100);
  --nuka-input-bg-readonly: var(--color-neutral-50);

  /* Input borders */
  --nuka-input-border: var(--color-neutral-300);
  --nuka-input-border-hover: var(--color-neutral-400);

  /* Scrollbar */
  --nuka-scroll-thumb: var(--color-neutral-400);
  --nuka-scroll-track: var(--color-neutral-100);

  /* Feedback */
  --nuka-success-base: var(--color-success-300);
  --nuka-success-bg: var(--color-success-100);
  --nuka-success-text: var(--color-success-500);
  --nuka-success-border: var(--color-success-300);
  --nuka-success-fg: var(--color-neutral-0);
  /* 5.51:1 on success-base (success-300). White on filled success surfaces. */

  --nuka-warning-base: var(--color-warning-300);
  --nuka-warning-fg: var(--color-neutral-900);
  /* Warning hue cannot pass 4.5:1 with white text at amber lightness.
     Dark foreground on warning surfaces. 7.11:1 on warning-300. */
  --nuka-warning-bg: var(--color-warning-100);
  --nuka-warning-text: var(--color-warning-500);
  --nuka-warning-border: var(--color-warning-400);

  --nuka-danger-base: var(--color-danger-300);
  --nuka-danger-bg: var(--color-danger-100);
  --nuka-danger-text: var(--color-danger-500);
  --nuka-danger-border: var(--color-danger-300);
  --nuka-danger-fg: var(--color-neutral-0);
  /* 4.65:1 on danger-base (danger-300). White on filled danger surfaces. */

  --nuka-info-base: var(--color-info-300);
  --nuka-info-bg: var(--color-info-100);
  --nuka-info-text: var(--color-info-500);
  --nuka-info-border: var(--color-info-300);
  --nuka-info-fg: var(--color-neutral-0);
  /* 4.69:1 on info-base (info-300). White on filled info surface. */
}

/* Semantic tokens: dark theme */
[data-theme="dark"] {
  /* Surfaces */
  --nuka-bg-base: var(--color-neutral-dark-base);
  --nuka-bg-subtle: var(--color-neutral-dark-subtle);
  --nuka-bg-muted: var(--color-neutral-dark-muted);
  --nuka-bg-emphasis: var(--color-neutral-0);

  /* Borders */
  --nuka-border-base: var(--color-neutral-dark-border);
  --nuka-border-strong: var(--color-neutral-500);
  --nuka-border-focus: var(--color-accent-400);

  /* Text */
  --nuka-text-base: var(--color-neutral-150);
  --nuka-text-muted: oklch(
    68% 0.01 257
  ); /* dark-only: trace tint for color temperature consistency */
  --nuka-text-subtle: oklch(
    46% 0.01 257
  ); /* dark-only: trace tint for color temperature consistency */
  --nuka-text-inverse: var(--color-neutral-950);
  --nuka-text-disabled: oklch(
    50% 0.01 257
  ); /* dark-only: visible but subdued */

  /* Accent */
  --nuka-accent-bg: var(--color-accent-500);
  --nuka-accent-bg-hover: var(--color-accent-480);
  --nuka-accent-bg-active: var(--color-accent-460);
  --nuka-accent-bg-subtle: oklch(
    35% 0.02 257
  ); /* dark-only: sits above bg-base */
  --nuka-accent-border: var(--color-accent-400);
  --nuka-accent-text: var(--color-accent-300);
  /*
   * NOTE: --nuka-accent-text uses accent-300 in dark mode.
   * Verified: 6.74:1 minimum (on bg-muted at 38% L). Passes AA.
   */
  --nuka-accent-fg: var(--color-neutral-0);
  --nuka-accent-bg-disabled: var(--color-neutral-700);

  /* Borders */
  --nuka-border-disabled: var(--color-neutral-700);

  /* Shadows */
  --nuka-shadow-card: var(--shadow-sm-dark);
  --nuka-shadow-overlay: var(--shadow-md-dark);
  --nuka-shadow-modal: var(--shadow-lg-dark);

  /* Overlay */
  --nuka-bg-overlay: oklch(0% 0 0 / 0.72);

  /* Input surfaces */
  --nuka-input-bg: var(--color-neutral-dark-input);
  --nuka-input-bg-disabled: var(--color-neutral-800);
  --nuka-input-bg-readonly: var(--color-neutral-dark-input-readonly);

  /* Input borders */
  --nuka-input-border: var(--color-neutral-700);
  --nuka-input-border-hover: var(--color-neutral-500);

  /* Scrollbar */
  --nuka-scroll-thumb: var(--color-neutral-dark-border);
  --nuka-scroll-track: var(--color-neutral-dark-subtle);

  /* Feedback */
  --nuka-success-base: var(--color-success-250);
  --nuka-success-bg: var(--color-success-600);
  --nuka-success-text: var(--color-success-200);
  --nuka-success-border: var(--color-success-300);
  --nuka-success-fg: var(--color-neutral-950);
  /* 4.65:1 on success-base (success-250). Dark fg on lighter dark-mode surface. */

  --nuka-warning-base: var(--color-warning-300);
  --nuka-warning-fg: var(--color-neutral-900);
  /* 7.30:1 on warning-base (warning-300). Only valid on warning-base,
     not warning-bg. See variants.ts for actual pairings. */
  --nuka-warning-bg: var(--color-warning-600);
  --nuka-warning-text: var(--color-warning-200);
  --nuka-warning-border: var(--color-warning-400);

  --nuka-danger-base: var(--color-danger-250);
  --nuka-danger-bg: var(--color-danger-600);
  --nuka-danger-text: var(--color-danger-200);
  --nuka-danger-border: var(--color-danger-400);
  --nuka-danger-fg: var(--color-neutral-950);
  /* 5.04:1 on danger-base (danger-250). Dark fg on lighter dark-mode surface. */

  --nuka-info-base: var(--color-info-300);
  --nuka-info-bg: var(--color-info-600);
  --nuka-info-text: var(--color-info-200);
  --nuka-info-border: var(--color-info-400);
  --nuka-info-fg: var(--color-neutral-950);
  /* Dark fg on lighter dark-mode info surface. Symmetric with danger/success/warning. */
}

/* Surface-level overrides: redefine focus ring for inverse surfaces inside each
   theme scope. The descendant selector (0,2,0) wins over the theme rule (0,1,0)
   when a [data-surface="inverse"] descendant is inside a themed subtree. See
   ADR-050 for the reasoning and the contrast ratios below. */

[data-theme="light"] [data-surface="inverse"],
:root [data-surface="inverse"] {
  /* accent-400 on neutral-900: ~6.9:1, passes WCAG 2.2 AA 3:1 for UI components */
  --nuka-border-focus: var(--color-accent-400);
}

[data-theme="dark"] [data-surface="inverse"] {
  /* accent-500 on neutral-0: ~7.8:1, passes WCAG 2.2 AA 3:1 for UI components */
  --nuka-border-focus: var(--color-accent-500);
}