<canvas id="canvas" width="400" height="200"></canvas>
canvas {
  border: 4px solid rgba(0, 0, 0, .2);
}
  let canvas = document.querySelector("#canvas")
  let ctx = canvas.getContext("2d")
  ctx.fillStyle ="blue"
  ctx.fillRect(10,10,50,50)

External CSS

  1. https://codepen.io/tutsplus/pen/vYrpEwd.css

External JavaScript

This Pen doesn't use any external JavaScript resources.