CSS — Cascading Style Sheets — is standard technology for management of pages registration of of the site. When the page is requested by the browser, one or several downloaded of .css-files say how elements of this page have to be issued.
.css-file in the theme of Drupal, differs in nothing from other same files in a network. However, procedure of addition of every files unique for this system. Drupal 5 (and the early version) and Drupal 6 (and the subsequent version) use different procedures of adding of these files. About connection of .css-files in different Drupal versions it is possible to learn having addressed to sections to the corresponding versions or another easy decision- to give a task for Drupaloutsourcing developers, which every day work with css styles in Drupal.
Some modules (both standard, and additional) use the .css-files which define registrations of those data which are generated by these modules. While these files can be edited as necessary in the folder of the module, it is recommended to copy (or to move) them in the folder of a subject, and then to correct those versions which lie in folders of a subject. During work with css technology in Drupal development important to make this with accuracy, because sometime with changing of one element, another can be changed too.
In certain cases, it is possible to know, that the HTML mark generated by the module doesn't contain selectors which would allow to issue data with use of CSS. For example, the module can apply the standard "h2" HTML tag to heading of site, while standards of coding demand use of a marking "/h2""h2 class="classmy"". In this case it is possible to change the marking generated by the module having used chance of redefinition of functions which the template.php file gives.
For work with CSS, there is a set of tools, but for full and work and right optimization of site, always needed knowledges and experience are necessary too. It is important to note that certain aspects of registration of the site can be changed without the aid of editing of styles, templates, the file of the description of a subject, etc. Besides, there are many additional modules for changing of control of interface of the site. For example in certain subjects it is possible to change the color scheme without editing of a code (compatibility and turning on of the Color module is required), without editing of a code it is possible to change a logo, a slogan of the site or its badge.
Using our services for editing of css, you will have a warranty of high-quality work with css code, which won't destroy work of other parts of your site.