ol.sommaire-main-list {
    list-style-type: none;
    counter-reset: section;
}

ol.sommaire-main-list > li::before {
    content: counter(section) ". ";
    counter-increment: section;
}

ol.sommaire-main-list > li > ol {
    list-style-type: none;
    counter-reset: subsection;
}

ol.sommaire-main-list > li > ol > li::before {
    content: counter(section) "." counter(subsection) " ";
    counter-increment: subsection;
}

ol.sommaire-main-list li > ol > li > a::before {
    content: none;
}