site/_src/_assets/styles/bigchain/_toc.scss

.toc {
    &,
    ol { counter-reset: item; }

    &,
    li { padding-left: 0; }

    &:before {
        @extend .h1;
        content: 'Table Of Contents';
        display: block;
        border-bottom: 1px solid $brand-main-blue-light;
        padding-bottom: $spacer;
        margin-bottom: ($spacer * 2);
        text-align: center;
    }

    li,
    ol { margin: 0; }

    li {
        display: block;

        // custom numbers
        &:before {
            content: counters(item, '.') ' ';
            counter-increment: item;
            margin-right: $spacer;
            color: $brand-main-gray;
        }
    }
}

// output by Kramdown

/* stylelint-disable selector-no-id  */
#markdown-toc {
    @extend .toc;
}

/* stylelint-enable  */