JSFiddle - React, Tailwind, and code Playground

HTML

<footer></footer>

CSS

footer {
    position: relative;
    width: 100%;
    height: 50px;
    background-color: #yellow;
}
footer:before {
    display: block;
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 50%;
    height: 50px;
    background-color: #yellow;
}
footer:after {
    display: block;
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    height: 0px;
    width: 0px;
    border: 25px solid transparent;
    border-left-color: #46475C;
}

.arrow {
    border: 10px solid transparent;
    border-left-color: black;
}