JSFiddle - React, Tailwind, and code Playground

HTML

<div class="top">
    <div class="triangle upperTriangle"></div>
</div>
<div class="bottom">
    <div class="triangle lowerTriangle"></div>
</div>
<div class="top">
    <div class="triangle"></div>
</div>

CSS

html, body {
    padding: 0; margin: 0;
    color: white;
}
.top {
    background-color: #282C34;
    height: 500px;
    width: 100%;
    position: relative;
}
.bottom {
    background-color: #3B3E48;
    height: 500px;
    width: 100%;
}
.triangle {
    border-left: 50vw solid transparent;
    border-right: 50vw solid transparent;
    width: 0;
    height: 0;
    bottom: -40px;
    content: "";
    display: block;
    position: absolute;
    overflow: hidden;
    left:0;right:0;
    margin:auto;
}
.upperTriangle {
    border-top: 40px solid #282C34;
}
.lowerTriangle {
    border-top: 40px solid red;
}