* {
    padding: 0px;
    margin: 0px;
    box-sizing: border-box;
}
body {
    min-height: 100%;
    background-color: #F7F7F7;
}
.Cssleft{
    overflow-y:auto;
    height:100%;
}
.Cssright {
    overflow-y: auto;
    height: 100%;
}
.CssClass div {
    display: block;
    border: 1px solid #E1E3E6;
    padding: 10px 5px;
}
.CssClassChapter {
    font-size:17px;
}
i.bi {
    cursor:pointer;
}
.CssClassUnit.active {
    background-color: #D8DCE2;
}
.CssClassUnit:hover {
    background-color: #D8DCE2;
}
.CssClassView {
    width:100%;
    height: 500px;
    display: flex;
    /* 水平置中 */
    justify-content: center;
    /* 垂直置中 */
    align-items: center;
    /*border: 1px solid #ff0000;*/
}
.CssHint {
    display: block;
    height: 300px;
}
    .CssHint .CssText {
        position: relative;
        top: 0;
        left: 50%;
        transform: translate(-50%, -50%);
    }