* {
  box-sizing: border-box;
}

body {
  display: flex;
  flex-direction: column;
  margin: 0;
  padding: 2rem;
  max-height: 100vh;
}

#tree {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  margin: 0 0 1rem 0;
}

#tree svg {
  height: 100%;
}

.button-container {
  display: flex;
  justify-content: center;
  flex: 0;
}

.button {
  font-size: 1.2rem;
  padding: 1rem 1.5rem;
  border-radius: 2px;
  background: hsl(150, 50%, 25%);
  color: #fff;
  border: 0;
  text-decoration: none;
  cursor: pointer;
  font-family: sans-serif;
  transition: background-color 0.2s ease-in-out, transform 0.2s ease-in-out;
}

.button:first-child { margin-right: 1rem;}
.button:hover { background: hsl(150, 50%, 20%); }
.button:active {
  background: hsl(150, 50%, 10%);
  transform: scale(0.98);
}