.container {
    width: 100%;
  max-width: 330px;
  margin: auto;
}

.keypad  button {
    margin: 1%;
    width: 31%;
    height: 22%;
    background: transparent;
    border: 1px solid #c4c4c4;
    border-radius: 7px;
    font-size: 1.5em;
    color: #c4c4c4;
    line-height: 1.75em;
}

.keypad  button.delete,
.keypad  button.submit {
    background: black;
    color: white;
}
.keypad  button.delete {
    background: tomato;
    color: white;
}
.keypad  button.submit {
    background: #9ACD32;
    color: white;
}