/* ============================================================
   vui-base.css  --  Design Tokens & Shared Foundation
   Zero-dependency UI library. Modern browsers only.
   ============================================================ */

/* --- Design Tokens --- */
:root {
  /* Background scale (soft black & white) */
  --vui-bg:            #fafafa;
  --vui-bg-surface:    #f2f2f2;
  --vui-bg-elevated:   #ffffff;
  --vui-bg-invert:     #1a1a1a;

  /* Foreground / text */
  --vui-fg:            #1a1a1a;
  --vui-fg-muted:      #6b6b6b;
  --vui-fg-subtle:     #999999;
  --vui-fg-invert:     #fafafa;

  /* Border */
  --vui-border:        #d4d4d4;
  --vui-border-strong: #a3a3a3;
  --vui-border-subtle: #e5e5e5;

  /* Accent (monochrome) */
  --vui-accent:        #1a1a1a;
  --vui-accent-hover:  #333333;
  --vui-accent-fg:     #fafafa;

  /* Danger / Error */
  --vui-danger:        #b91c1c;
  --vui-danger-fg:     #ffffff;

  /* Success */
  --vui-success:       #15803d;
  --vui-success-fg:    #ffffff;

  /* Radius */
  --vui-radius-sm:     4px;
  --vui-radius-md:     6px;
  --vui-radius-lg:     10px;

  /* Spacing */
  --vui-space-xs:      4px;
  --vui-space-sm:      8px;
  --vui-space-md:      16px;
  --vui-space-lg:      24px;
  --vui-space-xl:      40px;

  /* Typography */
  --vui-font-sans:     "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  --vui-font-mono:     "JetBrains Mono", "Fira Code", ui-monospace, monospace;
  --vui-font-size-xs:  0.75rem;
  --vui-font-size-sm:  0.875rem;
  --vui-font-size-base: 1rem;
  --vui-font-size-lg:  1.125rem;
  --vui-font-size-xl:  1.25rem;
  --vui-font-size-2xl: 1.5rem;
  --vui-font-size-3xl: 2rem;
  --vui-line-height:   1.6;

  /* Shadows */
  --vui-shadow-sm:     0 1px 2px rgba(0,0,0,0.06);
  --vui-shadow-md:     0 4px 12px rgba(0,0,0,0.08);
  --vui-shadow-lg:     0 8px 24px rgba(0,0,0,0.12);

  /* Transitions */
  --vui-duration:      150ms;
  --vui-easing:        cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Minimal Reset --- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--vui-font-sans);
  font-size: var(--vui-font-size-base);
  line-height: var(--vui-line-height);
  color: var(--vui-fg);
  background: var(--vui-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --- Shared Utilities --- */
.vui-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}