#book-tree{
    overflow-x: hidden;
    overflow-y: scroll;
    height: 100%;
    max-height: 1000px;
}
.book-tree-chapter{
    border-top: 1px solid #EFEFEF;
    border-right: 1px solid #EFEFEF;
    border-left: 1px solid #EFEFEF;
}
.book-tree-chapter:last-child {
    border-bottom: 1px solid #EFEFEF;
}
.book-tree-chapter{
    cursor: pointer;
}
.book-tree-chapter h4{
    margin: 0;
    padding: 0;
    background-color: #DEDEDE;
    font-size: 17px;
    padding: 3px;
}
.book-tree-chapter h4 span:first-child{
    font-size: 14px;
}
.book-tree-chapter h4.active{
    background-color: #CDCDCD;
}
.book-tree-chapter h4:hover{
    background-color: #CDCDCD;
}
ul.book-tree-chapter-sections{
    display: none;
    list-style: none;
    padding: 0;
    margin: 0;
}
.book-tree-chapter.expanded ul.book-tree-chapter-sections{
    display: block;
}

.book-tree-section{
    padding: 3px;
    font-size: 14px;
}

.book-tree-section.questions{
	background-color: skyblue;
}
.book-tree-section.quiz{
    background-color: #fab387;
}

.book-tree-section.active, .book-tree-section:hover{
    background-color: #095ab0;
    color: white;
}

.book-tree-section.loading{
    background: linear-gradient(64deg, #CDCDCD, #767676);
    background-size: 400% 400%;

    -webkit-animation: LoadingPage 1s ease infinite;
    -moz-animation: LoadingPage 1s ease infinite;
    animation: LoadingPage 1s ease infinite;
}
@-webkit-keyframes LoadingPage {
    0%{background-position:93% 0%}
    50%{background-position:0% 100%}
    100%{background-position:93% 0%}
}
@-moz-keyframes LoadingPage {
    0%{background-position:93% 0%}
    50%{background-position:0% 100%}
    100%{background-position:93% 0%}
}
@keyframes LoadingPage {
    0%{background-position:93% 0%}
    50%{background-position:0% 100%}
    100%{background-position:93% 0%}
}

@media only screen and (min-width: 641px){
    #book-tree{
        padding-left: 0;
    }
}