JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mainContent">
  <div id="someOtherElem"></div>
  <div id="canvasContainer">
    <canvas height="300" width="200"></canvas>
  </div>
</div>

SCSS

body {
  margin: 0;
}

#mainContent {
    background: grey;
    height: 100vh;
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
}

#someOtherElem {
    background: red;
    width: 200px;
    height: 200px;
    margin-left: 1rem;
}

#canvasContainer {
    display: flex;
    flex: 1;
    height: 100%;
    justify-content: center;
    align-items: center;
}

canvas {
    width: calc(100% - 2rem);
    height: calc(100% - 2rem);
    background: green;
    object-fit: contain;
}