html, body {
    height: 100%;
    display: flex;
    flex-direction: column;
}
.main {
    flex-grow: 1;
    border:1px;
    padding: 0px 20px 0px 20px;
    margin-bottom: 20px;
    font:16px/26px Georgia Garamond Serif;
    overflow:auto;
}
.sub{
    display: flex;
    justify-content: center;
    align-items: center;
}
.bottom{
    height: 80px;
}
.button {
    height:50px;
    width:200px;
    vertical-align: middle;
    border: 0;
    line-height: 2.5;
    font-size: 1rem;
    text-align: center;
    color: #fff;
    /*
    text-shadow: 1px 1px 1px #000;
    border-radius: 10px;
    */
    background-color: #00a13b;
    /* 
    background-image: linear-gradient(to top left,
                                      rgba(0, 0, 0, .2),
                                      rgba(0, 0, 0, .2) 30%,
                                      rgba(0, 0, 0, 0));
    */
    /*
    box-shadow: inset 2px 2px 3px rgba(255, 255, 255, .6),
                inset -2px -2px 3px rgba(0, 0, 0, .6);
    */
}

.button:hover {
    background-color: #50bc74;
}
/* 
.button:active {
    box-shadow: inset -2px -2px 3px rgba(255, 255, 255, .6),
                inset 2px 2px 3px rgba(0, 0, 0, .6);
}
*/