body {
    margin-left: 12%;
    margin-right: 12%;
    background-color: white
    }
h1, h2, h3, h4, h5 {
    text-align: center
    }
hr {
    text-align: center;
    width: 50%
    }
.toc {
    text-align: center
    }
.ctr {
    text-align: center
    }