JSFiddle - React, Tailwind, and code Playground

HTML

<div></div><div></div>

CSS

div {
    position: relative;
    width: 50%;
    height: 2000px;
   background-image: url("http://img3-fotki.yandex.net/get/6001/25874039.68/0_STATIC677fb_45e87780_L");
    margin-left: 25%;
}
div:first-child {
    position: fixed;
    width: 25%;
    height: 200px;
    background-color: rgba(0, 255, 0, 0.5);
    margin-left: 0;

    }