.background {
--tl: #3107ec;
--tr: #dba807;
--bl: #4cde1c;
--br: #4b4740;
width: 100%;
height: 100%;
border: 1px solid white;
position: relative;
background: linear-gradient(90deg, var(--tl), var(--tr));
}
.background:before {
content: "";
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
mask-image: linear-gradient(to bottom, transparent, black);
background: linear-gradient(90deg, var(--bl), var(--br));
}