:root {
  /* Colors */
  --color-bg:          #ffffff;
  --color-bg-alt:      #f8f9fa;
  --color-bg-dark:     #1a1a2e;
  --color-text:        #1a1a2e;
  --color-heading:     #0d0d0d;
  --color-muted:       #6b7280;
  --color-caption:     #9ca3af;
  --color-inverse:     #ffffff;
  --color-accent:      #3a8a4a;
  --color-accent-hover:#2e7a3c;
  --color-accent-light:rgba(58,138,74,0.10);
  --color-accent-bg:   rgba(58,138,74,0.06);
  --color-border:      #e5e7eb;
  --color-border-light:#f3f4f6;
  --color-success:     #10b981;
  --color-error:       #ef4444;

  /* Typography */
  --font-sans:   'Noto Sans JP','Inter','Helvetica Neue',Arial,sans-serif;
  --font-display:'Inter','Noto Sans JP',sans-serif;
  --text-xs:  .75rem;
  --text-sm:  .875rem;
  --text-base:1rem;
  --text-lg:  1.125rem;
  --text-xl:  1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  --leading-tight:  1.25;
  --leading-normal: 1.6;
  --leading-relaxed:1.8;
  --tracking-tight: -.025em;
  --tracking-wide:  .05em;
  --tracking-wider: .1em;

  /* Spacing (8px grid) */
  --sp-1: .25rem;  --sp-2: .5rem;  --sp-3: .75rem; --sp-4: 1rem;
  --sp-5: 1.25rem; --sp-6: 1.5rem; --sp-8: 2rem;   --sp-10:2.5rem;
  --sp-12:3rem;    --sp-16:4rem;   --sp-20:5rem;    --sp-24:6rem;
  --sp-32:8rem;

  /* Layout */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1200px;
  --gutter: var(--sp-6);

  /* Borders */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,.04);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,.06),0 2px 4px -2px rgba(0,0,0,.04);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,.06),0 4px 6px -4px rgba(0,0,0,.04);
  --shadow-card: 0 1px 3px rgba(0,0,0,.04),0 1px 2px rgba(0,0,0,.02);

  /* Transitions */
  --ease: cubic-bezier(.4,0,.2,1);
  --dur-fast: 150ms;
  --dur-normal: 300ms;
  --dur-slow: 500ms;

  /* Z-index */
  --z-dropdown:100; --z-sticky:200; --z-overlay:300; --z-modal:400;
}