*, *::before, *::after {
  box-sizing: border-box;
}

body {
  height: 100vh;
  margin: 0;
}

img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.add-button {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  background: lightgreen;
  border: none;
  cursor: pointer;
  font-size: 1.5rem;
  font-weight: bold;
}