NexusOS/assets/themes/NexusOS-icons-src/nexus-underlay-ring.svg

<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="128" height="128" viewBox="0 0 128 128">
  <defs>
    <radialGradient id="ring" cx="50%" cy="30%" r="70%">
      <stop offset="0%" stop-color="#8cc63f"/>
      <stop offset="100%" stop-color="#5a9020"/>
    </radialGradient>
    <radialGradient id="frame" cx="50%" cy="30%" r="70%">
      <stop offset="0%" stop-color="#b040c0"/>
      <stop offset="100%" stop-color="#4a0050"/>
    </radialGradient>
  </defs>
  <!-- Lime outer ring -->
  <rect x="0"  y="0"  width="128" height="128" rx="30" fill="url(#ring)"/>
  <!-- Purple gradient frame inset 8px from ring -->
  <rect x="8"  y="8"  width="112" height="112" rx="26" fill="url(#frame)"/>
  <!-- Dark inner border -->
  <rect x="12" y="12" width="104" height="104" rx="22" fill="#120018"/>
  <!-- App icon face -->
  <rect x="18" y="18" width="92"  height="92"  rx="16" fill="#262626"/>
</svg>