html{
    clear: page;
    background-color: silver;
    width: 50%;
    margin-left: auto;
    margin-right: auto;
}
#wrapper{
    display: grid;
    grid-template-columns: 100%;
    grid-template-rows: auto auto auto;

}
#b0{
    grid-column: 1/2;
    grid-row: 1/2;
}
#b1{
    grid-column: 1/2;
    grid-row: 2/3;
}
#b2{
    grid-column: 1/2;
    grid-row: 3/4;
}
h1{
    text-align: center;
    color: darkgreen;
}
#obj{
    color: #0b1163;
    font-size: 21px;
}
li{
    color: #4c4c4c;
    font-size: 18px;
}