style.css

body {
  margin:0;
  padding: 0;
  background-color: #222222;
  color: #eee;
}

img, canvas {
  max-width: 100%;
  height: auto !important;
  border: 1px solid #555;
  border-radius:4px;
  box-sizing: border-box
}

h4 {
  margin: 5px 0 10px;
}

main {
  margin: 0 auto;
  padding: 30px;
  min-height: 100vh;
  box-sizing: border-box;
}

input[type=text] {
  width: 100%;
  padding: 15px;
  margin-bottom: 20px;
  border-radius: 4px;
  border: 1px solid #555;
  background-color: #444;
  box-sizing: border-box;
  font-size: 1.2em;
  color: #eee;
  font-family: inherit;
}

input[type=color] {
  border-radius: 4px;
  border-color: #555;
  background-color: #444;
  height: 40px;
  width: 80px;
  display: inline-block;
  margin-bottom: 30px;
  cursor: pointer;
}

input[type=button] {
  padding: 10px 30px;
  background-color: #7F36AF;
  border-radius: 50px;
  border: none;
  color: #eee;
  font-family: inherit;
  font-weight: 500;
  font-size: 1em;
  margin-right: 10px;
  margin-bottom: 30px;
  transition: background-color .1s linear 0s;
  cursor: pointer;
}

input[type=button]:hover{
  background-color: #632a88;
  transition: background-color .1s linear 0s;
}

.border-bottom {
  border-bottom: 1px solid #7F36AF;
  margin-bottom: 10px;
  padding-bottom: 5px;
}