body {
    text-align: center;
}
button {
    transition: 200ms;
    border: none;
    border-radius: 2px;
    width: 250px;
    padding: 5px;
    margin: 5px;
    background-color: silver;
}

button:hover {
    transition: 200ms;
    background-color: gold;
}

.next {
    background-color: violet;
}

.next:hover {
    width: 500px;
    background-color: purple;
    color: white;
}