Hi,
From what I understand, fixing ie bugs usually involves Css Hack. Like

  *background:black; /* IE7*/
  _background:organge; /*IE6*/

I check default themes distributed with drupal core, and I find many ie.css files used to fix IE. However, there are no such specific signs in those ie.css like "_" used to indicate this css is only for IE browser. How do these themes accomplish this?
On the other hand, I don't see these ie css files are included within .info file. Is there a test for the browser, before these css files are rendered into html? Saying js will detect the browser is IE, so these ie.css files are rendered, while other css files are not used. If js detects the browser is not IE, like firefox, these ie.css files are not used.
Is that true? Thank you.

Comments

Hacks like that are old

Hacks like that are old school, and almost never used anymore. There is never any guarantee they will hold up to browser updates, so it's not a good practice to use them. And nowadays many designs are possible to code without any alteration for IE whatsoever. But when necessary, conditional stylesheets can be used. These are stylesheets that are only read by IE, thereby allowing IE only tweaks.

Jaypan We build websites

Hi, Jaypan, Thank you for

Hi, Jaypan,
Thank you for your reply. I just checked the template.php file. These css files are added to html.tpl template via drupal_add_css(), detecting the browser is IE.
I think you are right about the css hacks. Sometime I find a bug in IE, but later, I could find a way to fix that bug with some css skills, without doing css hacks.