JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
something

  <div class="gallery">
  Gallery
  </div>
</div>

CSS

body {
  margin: 0;
  padding: 0;
}
.wrapper {
      padding-left: 5px;
    padding-right: 5px;
    position: fixed;
    left: 50%;
    transform: translateX(-50%);
    max-width: 300px;
    width: 300px;
    background-color: red
  
}
.gallery {
  width: 100px; height: 100px; background-color: blue;
}