/* Bitcoin Sovereign Academy – Brand Tokens */
:root {
  /* Brand */
  --color-brand: #f7931a;
  --color-accent: #22d3ee;

  /* Neutrals */
  --color-bg: #0b0e14;
  --color-surface: #121723;
  --color-border: #202938;
  --color-chip: #1b2433;

  /* Text */
  --color-text: #e6edf3;
  --color-muted: #9aa4b2;
  --text-dim: #b3b3b3; /* 4.6:1 contrast - WCAG AA compliant */

  /* Status */
  --color-success: #4caf50;
  --color-danger: #f44336;
  --color-warning: #ff9800;
  --color-info: #2196f3;

  /* Optional demo-specific */
  --color-node-green: #00ff88;
  --color-node-red: #ff4444;

  /* Gradients */
  --gradient-brand: linear-gradient(135deg, #f7931a 0%, #ffb347 100%);
  --gradient-surface: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 100%);

  /* Radii and shadows */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --shadow-1: 0 2px 8px rgba(0,0,0,0.35);
  --shadow-2: 0 8px 24px rgba(0,0,0,0.45);

  /* Typography and spacing */
  --font-sans: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Arial, sans-serif;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-6: 24px;
  --space-8: 32px;
}

/* Minimal base defaults */
html, body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
}

a { color: var(--color-brand); }
a:hover { color: color-mix(in srgb, var(--color-brand) 85%, white); }

/* ============================================
   ACCESSIBILITY: Focus Indicators (WCAG 2.4.7)
   ============================================ */

/* Global focus styles for keyboard navigation */
*:focus {
  outline: 2px solid var(--color-brand);
  outline-offset: 2px;
}

/* Enhanced focus for interactive elements */
button:focus,
a:focus,
input:focus,
select:focus,
textarea:focus,
[role="button"]:focus,
[role="radio"]:focus,
[role="checkbox"]:focus,
[tabindex]:focus {
  outline: 3px solid var(--color-brand);
  outline-offset: 4px;
}

/* Remove outline for mouse users only (progressive enhancement) */
*:focus:not(:focus-visible) {
  outline: none;
}

/* Ensure keyboard users always see focus */
*:focus-visible {
  outline: 3px solid var(--color-brand);
  outline-offset: 4px;
  box-shadow: 0 0 0 4px rgba(247, 147, 26, 0.2);
}

/* ============================================
   ACCESSIBILITY: Skip Links (WCAG 2.4.1)
   ============================================ */

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-brand);
  color: #000;
  padding: 12px 20px;
  text-decoration: none;
  font-weight: 600;
  z-index: 10001;
  border-radius: 0 0 4px 0;
  transition: top 0.3s ease;
}

.skip-link:focus {
  top: 0;
  outline: 3px solid #fff;
  outline-offset: 2px;
}