body { background: rgb(30, 66, 200); overflow: hidden; } #sky { background: rgb(30, 66, 200); } .cloud { position: absolute; background-size: 25px; transition: left 5s, top 5s; /*background: radial-gradient(circle 50px, rgba(255, 255, 255, 0.5), rgba(20, 56, 200, 0.0) 90%) no-repeat;*/ }