errors within webdeveloper

i installed in my firefox browser the webdeveloper because i am looking for working with kind of SEO
when i am checking with this tool for example W3C CSS Validator i am getting:
W3C CSS Validator Resultaten met object : samenklaproos.nl/index.php (CSS versie 3)
Sorry! We vonden de volgende fouten (660)
So there are 660 css errors
Within all of the joomlaplates sites i am getting as many of this errors. Can you tell me the reason of it?
It is not a complaint but only question and is it possible to solve it?

Hi there,
not easy to answer your question!
1.) Error may come from the Joomla bootstrap.min.css file.
2.) Can be related to a missing tag from your content

Validation is an important part of your toolkit ( for detecting 'real' errors) but don't let it hold you back from adopting well established modern and progressive techniques.

More detail:
yootheme.com/themes/documentation/troubl...ng/validation-errors

thnaks for the answer but if i use the web developertool on your own original site i am also getting errors:
css errors 674 on www.joomlaplates.com/joomla-templates?start=12
css errors 481 on demo.joomlaplates.com/jp_pasta/

so can you tell me if you want to, if these really are errors which are causing kind of lets say google troubles
my own site is giving 664 css errors with the tool

can you advice me what to do for reducing the errors

Hi there,
you can not reduce the errors, thats fact.
Activate the original "protostar theme" and then check the css code validator and you will get the same errors again.
CSS Validation is simply overrated.

BTW if youre not happy with the theme, you can get a refund!

1) i am just very happy with your templates.

i found this answer with google and am satisfied with the answer. i think this is the issue and in my opinion after reading it no errors:

These “css errors” are actually no errors but the code is required to maintain the cross browser compatibility for webkit browser users. The browser specific prefixes (like -webkit, -moz, etc.) are not part of the CSS3 specifications and thus the w3c validator will mark them as “errors” although the code makes sense and works perfectly fine. Removing the code can cause styling issues for some users and that’s why we think it’s better to use browser prefixes even if w3c does not accept them. In addition I’m not sure who told you that 100% valid css code will improve your seo but you’re wasting your time – search engines do not care about these browser prefixes at all. Even invalid html code can make sense – i.e. if you add semantic markup to the code which is not part of the html5 standard and which helps the search engines to parse your content. See also: yoast.com/w3c-validation-seo/

Exact what I´ve told you.
CSS errors are overrated