JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box">Элемент с градиентными рамками по бокам</div>

CSS

#box {
    background:yellow;
    border-left:3px solid;
    border-right:3px solid;
    border-image: linear-gradient(to bottom, blue, red) 1 100%;
    height:100px;
    padding:10px;
}