<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
  <defs>
    <!-- Gradient definition -->
    <linearGradient id="grad" x1="0%" y1="0%" x2="100%" y2="100%">
      <stop offset="0%" style="stop-color:#00e5ff;stop-opacity:1" />
      <stop offset="100%" style="stop-color:#ff3366;stop-opacity:1" />
    </linearGradient>
  </defs>
  
  <!-- Dark background circle -->
  <circle cx="50" cy="50" r="48" fill="#050814" stroke="url(#grad)" stroke-width="2"/>
  
  <!-- Letter "B" -->
  <text 
    x="50" 
    y="50" 
    font-family="system-ui, -apple-system, sans-serif" 
    font-size="48" 
    font-weight="800" 
    fill="url(#grad)" 
    text-anchor="middle" 
    dominant-baseline="central"
    letter-spacing="1">B</text>
</svg>