.block{
    height: 400px;
    width: 100%;
    position: relative;
    background: linear-gradient(to right, rgba(241,231,103,1) 0%, rgba(254,182,69,1) 100%);
}
.block::after{
    content: '';
    width: 100%;
    height: 100%;
    position: absolute;
    background: inherit;
    z-index: -1;
    bottom: 0;
    transform-origin: left bottom;
    transform: skewY(3deg);
}