JSFiddle - React, Tailwind, and code Playground

HTML

<div>This border is just to show you that it fades to the background color, which is white.</div>

CSS

div {
    width: 500px;
    height: 450px;
    background: #206fa0; /* Old browsers */
background: -moz-linear-gradient(top,  #206fa0 0%, #2989d8 50%, #ffffff 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#206fa0), color-stop(50%,#2989d8), color-stop(100%,#ffffff)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top,  #206fa0 0%,#2989d8 50%,#ffffff 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top,  #206fa0 0%,#2989d8 50%,#ffffff 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top,  #206fa0 0%,#2989d8 50%,#ffffff 100%); /* IE10+ */
background: linear-gradient(to bottom,  #206fa0 0%,#2989d8 50%,#ffffff 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#206fa0', endColorstr='#ffffff',GradientType=0 ); /* IE6-9 */
    border-top: 5px black solid;
    border-left: 5px black solid;
    border-right: 5px black solid;
}