JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
    <div class="block">
        
    </div>
</div>

CSS

.wrapper {
    height: 500px;
    width: 700px;
    padding-top: 50px;
    background: #ff670f; /* Old browsers */
    background: -moz-linear-gradient(top,  #ff670f 0%, #d5ef0e 100%); /* FF3.6+ */
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#ff670f), color-stop(100%,#d5ef0e)); /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(top,  #ff670f 0%,#d5ef0e 100%); /* Chrome10+,Safari5.1+ */
    background: -o-linear-gradient(top,  #ff670f 0%,#d5ef0e 100%); /* Opera 11.10+ */
    background: -ms-linear-gradient(top,  #ff670f 0%,#d5ef0e 100%); /* IE10+ */
    background: linear-gradient(to bottom,  #ff670f 0%,#d5ef0e 100%); /* W3C */
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ff670f', endColorstr='#d5ef0e',GradientType=0 ); /* IE6-9 */
}
.block {
    margin: 0 auto;
    height: 300px;
    width: 200px;
    background: #fff;
    position: relative;
}
.block:before {
    display: block;
    content: " ";
    position: absolute;
    right: 0;
    top: 0;
    border-width: 0 14px 14px 0;
    border-style: solid;
    border-color: red transparent;
}