In true words HTML and CSS are the glossy languages of internet.  In simpler way whatever you see on a webpage is landed on the part of HTML or CSS components. May be you are the master of all the web languages but there still are silly mistakes which make us search for css fix on the various internet forums and blogs. Rather than going beyond on the CSS gyan i would like to introduce top 10 HTML and CSS resource used by web designers and programmers.
Top 10 HTML CSS Resources Top 10 HTML / CSS Resources

Yourhtmlsource – This site has excellent HTML tutorials and well-researched links on all aspects of web design, equally suited to beginners and advanced webmasters.

W3schools – Again as mentioned earlier this source can be of great help if you desiring to learn HTLM.

Htmldog – I’m sure you know this site. The idea of HTLM Dog is to take the somewhat convoluted official specs for XHTML and CSS and present them in a much more readable fashion.

W3– This short tutorial is meant for people who want to start using CSS and have never written a CSS style sheet before.

Htmlcsstutorials – A nice site designed with easy navigation to offer you knowledge about XHTML and tips on CSS. You get complete reference for html CSS with examples.

Html – HTML.net provides guidance and help about designing and developing websites.

Tizag – This can be a stepping stone to the budding webmaster and a handy reference to the veteran developer. Tizag is always changing its tutorials and references to incorporate the latest in web design.

Boogiejack – This is an HTML help site featuring standards-based HTML tutorials, CSS tutorials and other website design help and resources.

Htmlgoodies – This site has group of lessons set up to be covered over a week’s time, one tutorial per day. HTMLGoodies is your resource for HTML, CSS, JavaScript, PHP, ASP and other web development topics.

Echoecho– You can use this tutorial either as a complete introduction or as an A-Z reference to HTML. If you’re completely new to HTML you should start with the section that covers HTML Basics.

Css-tricks – You can locate hand-full of video and text tutorials with CSS-trick. Don’t forget to sign up with their RSS to get some smart tricks on CSS.