Gradientes

Combine manchas de cor sobre um fundo e copie o CSS. Arraste os pontos no preview.

CSS

background-color: #ffffff;
background-image:
    radial-gradient(60% 78% at 8% 10%, #2563ebff, transparent 70%),
    radial-gradient(55% 72% at 92% 95%, #22b8cfe6, transparent 70%);