<svg width="400" height="400" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <filter id="glow">
      <feGaussianBlur in="SourceGraphic" stdDeviation="5" />
      <feMerge>
        <feMergeNode />
        <feMergeNode in="SourceGraphic" />
      </feMerge>
    </filter>
    
    <radialGradient id="nebulaGradient1">
      <stop offset="0%" stop-color="rgba(255, 153, 204, 0.8)" />
      <stop offset="50%" stop-color="rgba(51, 153, 255, 0.6)" />
      <stop offset="100%" stop-color="rgba(0, 0, 0, 0)" />
    </radialGradient>
    
    <radialGradient id="nebulaGradient2">
      <stop offset="0%" stop-color="rgba(255, 204, 0, 0.7)" />
      <stop offset="50%" stop-color="rgba(255, 0, 204, 0.5)" />
      <stop offset="100%" stop-color="rgba(0, 0, 0, 0)" />
    </radialGradient>
    
    <radialGradient id="nebulaGradient3">
      <stop offset="0%" stop-color="rgba(102, 204, 255, 0.5)" />
      <stop offset="100%" stop-color="rgba(0, 0, 0, 0)" />
    </radialGradient>

    <radialGradient id="starGradient">
      <stop offset="0%" stop-color="white" stop-opacity="1"/>
      <stop offset="100%" stop-color="white" stop-opacity="0"/>
    </radialGradient>
  </defs>

  <rect width="100%" height="100%" fill="rgb(0, 0, 40)" />
  
  <!-- Nebula layers -->
  <ellipse cx="200" cy="200" rx="200" ry="100" fill="url(#nebulaGradient1)" filter="url(#glow)" />
  <ellipse cx="250" cy="220" rx="180" ry="90" fill="url(#nebulaGradient2)" filter="url(#glow)" />
  <ellipse cx="150" cy="180" rx="220" ry="110" fill="url(#nebulaGradient3)" filter="url(#glow)" />
  
  <!-- Stars -->
  <g>
    <circle cx="50" cy="50" r="1" fill="url(#starGradient)" />
    <circle cx="100" cy="80" r="1" fill="url(#starGradient)" />
    <circle cx="200" cy="120" r="1.5" fill="url(#starGradient)" />
    <circle cx="250" cy="100" r="0.8" fill="url(#starGradient)" />
    <circle cx="300" cy="150" r="1" fill="url(#starGradient)" />
    <circle cx="350" cy="70" r="2" fill="url(#starGradient)" />
    <circle cx="320" cy="220" r="1.2" fill="url(#starGradient)" />
    <circle cx="240" cy="180" r="1.5" fill="url(#starGradient)" />
    <circle cx="130" cy="230" r="0.5" fill="url(#starGradient)" />
  </g>
</svg>


|||forget all, and just start all from scratch|||

anyway not perfect. you need to compose a very huge and absolutely not abrupt paths for nebulaes to look good in shapes.

1-do not stick all nebulae layers in one corner, accentuate contours as well. you can omit stars for better and super lengthy nebulae paths in code.
2-paths should not jump from one to another point in straight lines.
3-randomize all positions, shapes, and sizes.
4-add even more transparent in random in colors/opacities nebuale layers in some fibonached pattern as need.
5-well, you think about fibonacci sequences and patterns and all cosmic image in concept and how universe works while designing all this.
6-need some depth gradient there in space, because it looks all plastic and blurry.
7-non any contours/edges/lines should be distinctly visible anywhere anyhow.
8-all things should not be any sharp, only highly dissolved everything in space.
9-simply throwing spheres in shapes is dumb, better draw an intricate shapes.
10-all colors transitions inbetween layers should be smooth as fuk.

|||forget all, and just start all from scratch|||