body {
  --color: #ff6b81;

  display: flex;
  flex-direction: column;

  height: 100vh;
  width: 100vw;

  margin: 0;
  padding: 0;
}
.top {
  display: flex;
  align-items: center;

  height: 5rem;
  width: 100%;

  padding: 1rem;
  box-sizing: border-box;

  background-color: var(--color);
}
.top > * {
  display: flex;
  justify-content: center;
  align-items: center;

  height: 3rem;
  width: 3rem;
  font-size: 2rem;
  margin: 0.5rem;
}
.top button {
  outline: none;
  border: none;
  border-radius: 50%;

  color: var(--color);
}
.top button:active {
  transform: scale(0.98);
}
.top .sub::after {
  content: "I";
  transform: rotate(90deg);
}
.top .size {
  color: white;
}
.top .space {
  flex-grow: 1;
}
canvas {
  height: calc(100% - 7rem);
  width: calc(100% - 2rem);
  border: 1rem solid var(--color);
}