CSS style guide question

What are the best practices with respect to styling HTML elements using CSS? What's the preferred granularity for styling HTML elements? i.e., do you have lots of 开发者_如何学Python

div.searchbox input

div.searchbox p

div.searchbox p.help

OR

input.searchbox

p.searchbox

p.searchboxhelp

Which css code is considered easy to maintain? Is using grid frameworks and reset considered best practice?

Thanks

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I totally prefer the first approach. The search box is a defined entity with specific styling rules. If the search box has unique visual settings that no other element on the page has, which is usually the case, that is the way to go.

If there are any global rules in addition, you'd define them globally in a different section of the style sheet:

input { font-size: 16px; color: blue }

If there are any rules that a number of input elements on the page (not all in the search box) should share (e.g. "the search input field, and the login input fields should stand out a bit, and have a yellow background") you can create a global class in addition to the "local" rules:

input.highlight { background-color: yellow }

and add that class definition to every input:

<div class="searchbox">
 <input type="text" class="highlight">  <!-- Gets applied the "highlight" 
                                             and the "searchbox" styles -->
</div>

But the basic foundation should always be a "local" set of rules as you do in your first example IMO.

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I normally try to reach a compromise between:

input.searchbox

and

body div#layout div#main div#content div.section div.subsection form input.searchbox