This is your first real post. Write normal markdown here — headings, code blocks, lists, whatever. This file’s frontmatter (the part between the --- lines above) is what the listing page and the post page both read to know the title/date/tag without you typing it twice.

a heading works fine

int main(void) {
    return 0;
}

Once this renders correctly at /blog/boot-sector-notes, the mechanism is proven — every future post is just a new file like this one, nothing else to touch.