.bouton1
{
    background-image: linear-gradient(to top, #00FF00 0%, #A0C8FA 10%, blue 70%); 
    transition-property: background-image;
    width: 150px; 
    height: 60px; 
    font-weight: bold; 
    font-size : 18px; 
    margin-left: 230px; 
    color: #FFFFFF;
}
.bouton1:hover
{
    cursor: pointer;
    background-image: linear-gradient(#003300, #00FF00);
}