body {
  background-color: white;
  color: green;
  font-family: sans-serif;
  text-align: center;
}

button {
  background-color: orange;
  color: white;
  font-size: 1.4rem;
  padding: 0.5rem;
  margin: 0.3rem;
  min-width: 7rem;
  min-height: 4rem;
  border: 0;
}

div {
  text-align: center;
}

td {
  font-size: 2rem;
  min-width: 4rem;
}

#seconds {
  color: red;
  font-size: 1.2rem;
}