#toc {
    width: 250px;
    background-color: var(--bg-color);
    border-left: 1px solid var(--border-color);
    padding: 20px;
    overflow-y: auto;
    height: calc(100vh - 60px);
}

.toc-content {
    position: relative;
    padding-left: 15px;
}

.toc-item {
    position: relative;
    padding: 4px 0;
    cursor: pointer;
    display: block;
    color: var(--text-color);
}

.toc-item::before {
    content: '';
    position: absolute;
    left: -15px;
    top: 50%;
    width: 10px;
    height: 1px;
    background-color: var(--border-color);
}

.toc-item[data-level="1"] { 
    font-weight: bold;
    font-size: 1.1em;
    margin-left: 0px; 
}
.toc-item[data-level="2"] { margin-left: 15px; }
.toc-item[data-level="3"] { margin-left: 30px; }
.toc-item[data-level="4"] { margin-left: 45px; }
.toc-item[data-level="5"] { margin-left: 60px; }
.toc-item[data-level="6"] { margin-left: 75px; }

.toc-item:hover {
    color: var(--border-color);
}

.toc-item.active {
    color: var(--border-color);
    font-weight: bold;
}

.section-highlight {
    position: relative;
    background-color: rgba(var(--border-color-rgb), 0.1);
}

.section-highlight::after {
    content: '';
    position: absolute;
    left: -20px;
    top: 0;
    bottom: 0;
    width: 3px;
    background-color: var(--border-color);
}