:root {
  /* Base neutrals */
  --color-paper:      #F7F4F0;
  --color-paper-deep: #EDE8E1;
  --color-surface:    #FFFFFF;
  --color-ink:        #2C2420;

  /* Ink opacity scale */
  --color-ink-06:  rgba(44, 36, 32, 0.06);
  --color-ink-12:  rgba(44, 36, 32, 0.12);
  --color-ink-24:  rgba(44, 36, 32, 0.24);
  --color-ink-40:  rgba(44, 36, 32, 0.40);
  --color-ink-60:  rgba(44, 36, 32, 0.60);
  --color-ink-80:  rgba(44, 36, 32, 0.80);
  --color-ink-100: rgba(44, 36, 32, 1.00);

  /* Accent */
  --color-accent:      #8B7355;
  --color-accent-dark: #6B5540;
  --color-accent-soft: #C9B99A;

  /* Semantic */
  --color-success: #5A8A6A;
  --color-warning: #C49A3C;
  --color-danger:  #B05050;
  --color-info:    #5C7A96;

  /* Type stack */
  --font-sans:  "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic Medium", "Yu Gothic", Meiryo, sans-serif;
  --font-serif: "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic Medium", "Yu Gothic", Meiryo, sans-serif;
  --font-mono:  "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;

  /* Type scale */
  --text-xs:   0.694rem;
  --text-sm:   0.833rem;
  --text-base: 1rem;
  --text-md:   1.125rem;
  --text-lg:   1.25rem;
  --text-xl:   1.5rem;
  --text-2xl:  1.875rem;
  --text-3xl:  2.25rem;
  --text-4xl:  3rem;
  --text-5xl:  3.75rem;

  /* Line-height */
  --leading-display: 1.15;
  --leading-heading: 1.4;
  --leading-body:    1.9;
  --leading-ui:      1.5;
  --leading-tight:   1.2;

  /* Letter-spacing */
  --tracking-ja:      0.08em;
  --tracking-upper:   0.12em;
  --tracking-display: 0.16em;

  /* Spacing scale (8px base) */
  --s-1:  4px;
  --s-2:  8px;
  --s-3:  12px;
  --s-4:  16px;
  --s-5:  20px;
  --s-6:  24px;
  --s-8:  32px;
  --s-10: 40px;
  --s-12: 48px;
  --s-14: 56px;
  --s-16: 64px;
  --s-20: 80px;
  --s-24: 96px;
  --s-28: 112px;
  --s-32: 128px;
  --s-36: 144px;
  --s-40: 160px;

  /* Borders */
  --border-hairline: 1px solid var(--color-ink-12);
  --border-strong:   1px solid var(--color-ink-40);
  --border-focus:    2px solid var(--color-accent);

  /* Radii */
  --radius-none: 0px;
  --radius-sm:   4px;
  --radius-md:   8px;
  --radius-lg:   16px;
  --radius-pill: 9999px;

  /* Shadows */
  --shadow-1: 0 1px 4px rgba(44, 36, 32, 0.08), 0 1px 2px rgba(44, 36, 32, 0.06);
  --shadow-2: 0 4px 16px rgba(44, 36, 32, 0.10), 0 2px 6px rgba(44, 36, 32, 0.08);

  /* Motion */
  --ease-out:   cubic-bezier(0.22, 1, 0.36, 1);
  --dur-micro:  80ms;
  --dur-small:  160ms;
  --dur-medium: 300ms;

  /* Layout */
  --max-w:    1080px;
  --gutter:   24px;
  --header-h: 64px;
}