docs/source/_static/scss/includes/_toc.scss

div.topic {
    all: revert;
}

.content__toc {
    position: sticky;
    top: 0;

    @include breakpoint-min(breakpoints(lg)) {
        flex-shrink: 0;
        order: 2;
        width: 14rem;
        height: calc(100vh - 6.0625rem); // 6.0625rem = header height
        padding: var(--content-padding) var(--content-padding) var(--content-padding) 0;
        overflow-y: auto;

        .icon {
            display: none;
        }
    }

    @include breakpoint-max(breakpoints(lg)) {
        display: flex;
        gap: 0.75rem;
        align-items: center;
        padding: var(--content-padding);
        background-color: var(--body-bg);
        z-index: $z-index-header - 2;
    }

    .icon {
        height: 2.5rem;
        width: 2.5rem;
        padding: 0.7rem;
        border: 1px solid var(--theme-light-bg);
        cursor: pointer;

        &:last-child {
            margin-left: auto;
        }
    }

    &.active {
        #table-of-contents {
            & > ul { 
                display: block;
            }
        
            .topic-title {
                border-radius: $border-radius $border-radius 0 0;
    
                &:after {
                    transform: rotate(180deg);
                }
            }
        }
    }
}

.content__toc--empty {
    @include breakpoint-min(breakpoints(lg)) {
        display: none;
    }
}

#table-of-contents {
    flex: 1;
    position: relative;

    .topic-title {
        color: var(--headings-color);
        margin: 0;
        line-height: 1;
        font-size: $font-size-md;

        @include breakpoint-max(breakpoints(lg)) {
            padding: 0.85rem 1rem;
            background-color: var(--theme-light-bg);
            border-radius: $border-radius;
            display: block;
            position: relative;
            font-size: $font-size-sm;
            cursor: pointer;

            &:after {
                content: "";
                height: 1rem;
                width: 1rem;
                position: absolute;
                right: 1rem;
                top: 0.8rem;
                background: var(--toc-caret-icon) no-repeat center;
                background-size: 0.8rem;
                transform-origin: center;
            }
        }
    }

    ul {
        list-style: none;
        padding: 0;
        margin: 0;
        font-size: $font-size-sm;
        color: var(--text-muted-color);

        ul {
            margin-left: 0.75rem;
        }
    }

    & > ul {
        @include breakpoint-min(breakpoints(lg)) {
            position: relative;
            padding-left: 1rem;
            margin-top: 1rem;
        
            &:before {
                content: "";
                width: 2px;
                height: calc(100% - 0.8rem);
                position: absolute;
                left: 0.2rem;
                top: 0.5rem;
                background-color: var(--theme-light-bg);
            }
        }

        @include breakpoint-max(breakpoints(lg)) {
            position: absolute;
            left: 0;
            top: 100%;
            width: 100%;
            background-color: var(--toc-dropdown-bg);
            display: none;
            border-radius: 0 0 $border-radius $border-radius;
            z-index: 1;
            padding: 0.65rem 1rem 1rem;
            max-height: 12rem;
            overflow-y: auto;
        }

        a {
            display: block;
            color: var(--text-muted-color);
            padding: 0.15rem 0;

            code {
                display: none;
            }

            &:hover {
                color: var(--text-color);
            }
        }
    }
}