.content {
    padding: 3px;
    text-align: center;
}
.greeting .first {
    text-align: center;
    margin: 20px;
    color: white;
    font-size: 2.0vw;
}
.greeting .second {
    text-align: center;
    margin: 10px;
    color: darkblue;
    font-size: 1.25vw;
} 
.greeting .third {
    text-align: center;
    margin: 0px;
    color: green;
    font-size: 1.25vw;
}    
.mainimage {
    max-width: 60%;
    height: auto;
    display: block;
    margin: 0 auto;
}
.button {
    background-color: blue;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1.5vw;
    text-align: center;
    display: inline-block;
    margin-top: 10px;
}