Why isn't there an HTML tag to diminish content?

Yesterday I was building a template for a newspage. I wanted a <h2> that contains the date of the news item. Since I wanted the date to be less important than the rest of the text in the <h2> I went looking for an HTML开发者_运维问答 tag that can semantically diminish content. But this doesn't exist.

So why isn't there something like a <dim> (diminish tag) tag that is more or less a negative of the <em> tag?

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I've seen people using the small tag for this kind of semantics.

What I've used before was time with a pubdate attribute. That should satisfy the semantics even more.

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markup:

<span class="dim">content</span>

css:

.dim{font-size:0.9em}

That combination should allow the font-size to get gradually smaller as the tags are nested deeper. From the browser's point of view it's semantically meaningless but it's an OK first step.

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if it is less important than h2 it should be wrapped in h3 or lower. use css to style it.

but not nested....