Here is a brain teaser. Apply styles just to paragraphs in Catalan language assuming following markup and of course solution shouldn't be tightened to paragraphs exact position, order or depth:

< html lang = "ca" > < head > < meta charset = "utf-8" > < title > Salut! Txin txin! </ title > </ head > < body > < p > No n'hi ha prou amb una llengua </ p > < article lang = "en" > < h1 > Phrase of the day </ h1 > < p > When the going gets tough, the tough get going </ p > </ article > </ body > </ html >

Before diving into the solving part let's refresh our minds on what is a lang attribute:

lang attribute specifies the base language of an element's attribute values and text content. The default value of this attribute is unknown.

Refer to ISO 639 Language Codes list for valid values.

Tip: It's considered a good practice to set lang attribute in <html> tag, at least at least (think of search engines, speech synthesizers etc.)

#First Guess

One possibly working option would be utilizing attribute selector introduced in CSS2 which is widely supported today:

[lang="ca"] p { background-color : yellow; color : red; }

..right? Well, not. This would apply the styles to all paragraphs including the one in English which is not what we want.

What we really need here is a less known :lang pseudo class selector which has even wider support among vendors than attribute selectors:

p :lang(ca) { background-color : yellow; color : red; }

What it actually does is it selects elements that have inherited the specified language from their parents. Because paragraph in English has two parents with lang attribute ( <article lang="en"> , <html lang="ca"> ) and the closer one has value of en it is out of our selector's scope.

While there most likely isn't much of need in styling elements based on their locale it's definitely worth knowing the difference between using attribute selector and :lang pseudo class when filtering locale-specific elements.

So if you find yourself using attribute selector to style locale-specific content, I'd suggest to consider using :lang pseudo class selector instead.

Hopefully this post shows the difference between two approaches clearly and demonstrates proper problem solving.