h1 {
    font-size: 140%;
    text-align: center
    }
h2 {
    font-size: 120%;
    text-align: center
    }
h3 {
    font-size: 100%;
    font-weight: bold
    }
h4 {
    font-size: 100%;
    font-weight: normal
    }
i {
    font-weight: bold
    }
.ip {
    margin-top: 0;
    margin-bottom: 0.3em
    }
.exercise_h1 {
    margin-left: 0
    }
.exercise_h2 {
    margin-left: 1.5em
    }
.exercise_h3 {
    margin-left: 2.5em
    }
.exercise_h4 {
    margin-left: 3.5em
    }