What Is the Best Method for Tidying CSS

What is the best method for tidying CSS?

You might want to encapsulate your css within a more formal CSS framework. You can create your own custom framework but there are some useful open source css frameworks such as yahoo's YUI and Blue Print CSS
http://www.blueprintcss.org/

The nice thing about this approach is that it leverages a lot of effort to fix the cross browser issues around fonts and layout.

Depending how far you go you may have to extensively touch the existing markup. Depending on how large your site is I would try to incrementally adjust styles and migrate them over to the formal CSS framework. Long term this will make the CSS more manageable and easily understood by other developers familiar with the concept of the framework.

Progressively try to eliminate redundant and unaccounted for styles.

I would also create a debug.css file. Take all the old style names and add an identifying style to them. For example:

.myoldstyle {border: solid 1px red};

Then you can detect where the old style is being used throughout the site. Each style should be accounted for and ported over to the new system. When a particular style in the old system has been correctly migrated to the new system you can remove (or better comment out) the identifying style from the debug.css file. You can be confident that you have migrated all the styles when the debug.css shows no side affects in the display output.

It can be a time consuming process but approaching it systematically can be helpful.

Also, you may want to start looking at your site with no css at all. Just get a sense of the logical and semantic markup of code. Having a clean HTML code base helps when debugging style quirks.

As for organization of CSS, I like to separate into basic categories: layout, typography, lookandfeel, navigation

Keep all color related information in the lookandfeel style sheet. This is where you will spend the most time trying to meet the client's visual tastes and desires. It is handy to keep that is a separate logical style sheet. The other stuff is more functional and standardized. Having this abstraction makes it much easier to isolate the visual effects of styles.

And one last tip, check out Firefox firebug plugin or Safari's debbugger. These can show you computed styles (the way styles and elements are ultimately derived as the various styles are applied) and you can tweak specific styles in real time on the fly it you want to explore the effects of a specific style change in a complex CSS system.

And most importantly, keep a separate ie.css file around. This should be the last style sheet referenced in your headers. If you need to do any workarounds for IE put them here. And only expose this style sheet to IE through conditional comments.

http://www.quirksmode.org/css/condcom.html

That is the fastest way to resolve IE 6 problems.

Tidying up css?

You can use the Dust-Me Selectors Firefox add-on for selecting unused selector.

How can I effectively clean up styles in a large web site?

Short of going through each .tpl file and searching the file for the selectors manually, I don't see any other way.

You could of course use Dust-Me selectors, but you'd still have to go through each page that uses the .tpl files (not each url as I know that many of them will be duplicates).

Sounds like a big job! I had to do it once before and I did exactly that, took me a week.

Another tool is a Firebug plugin called CSS Usage. As far as I read it can work across multiple pages but might break if used site-wide. Give it a go.

Triumph! Check out the Unused CSS online tool. Type your index url into the field and voila, a few minutees later a list of all the used selectors :) I know you want the unused ones, but then the only work is finding the unused ones in the file (ctrl+f) and removing them :)

Make sure to use the 2nd option, they'll email you the results of the crawl of your entire webpage. Might take up to half an hour, but that's far better than a week. Take some coffee :)

Just tested it, works a treat :)

Managing CSS Explosion

This is a very good question. Everywhere I look, CSS files tend to get out of control after a while—especially, but not only, when working in a team.

The following are the rules I myself am trying to adhere to (not that I always manage to.)

Refactor early, refactor often. Frequently clean up CSS files, fuse together multiple definitions of the same class. Remove obsolete definitions immediately.
When adding CSS during fixing bugs, leave a comment as to what the change does ("This is to make sure the box is left aligned in IE < 7")
Avoid redundancies, e.g. defining the same thing in .classname and .classname:hover.
Use comments /** Head **/ to build a clear structure.
Use a prettifier tool that helps maintain a constant style. I use Polystyle, with which I'm quite happy (costs $15 but is money well spent). There are free ones around as well (e.g. Code Beautifier based on CSS Tidy, an open-source tool).
Build sensible classes. See below for a few notes on this.
Use semantics, avoid DIV soup - use <ul>s for menus, for example.
Define everything on as low a level as possible (e.g. a default font family, colour and size in the body) and use inherit where possible
If you have very complex CSS, maybe a CSS pre-compiler helps. I'm planning to look into xCSS for the very same reason soon. There are several others around.
If working in a team, highlight the necessity of quality and standards for CSS files as well. Everybody's big on coding standards in their programming language(s), but there is little awareness that this is necessary for CSS too.
If working in a team, do consider using Version Control. It makes things that much easier to track, and editing conflicts that much easier to solve. It's really worth it, even if you're "just" into HTML and CSS.
Do not work with !important. Not only because IE =< 7 can't deal with it. In a complex structure, the use of !important is often tempting to change a behaviour whose source can't be found, but it's poison for long-term maintenance.

Building sensible classes

This is how I like to build sensible classes.

I apply global settings first:

body { font-family: .... font-size ... color ... }
a { text-decoration: none; }

Then, I identify the main sections of the page's layout—e.g. the top area, the menu, the content, and the footer. If I wrote good markup, these areas will be identical to the HTML structure.

Then, I start building CSS classes, specifying as much ancestry as possible as long as it is sensible, and grouping related classes as closely as possible.

div.content ul.table_of_contents 
div.content ul.table_of_contents li 
div.content ul.table_of_contents li h1
div.content ul.table_of_contents li h2
div.content ul.table_of_contents li span.pagenumber

Think of the whole CSS structure as a tree with increasingly specific definitions the further away from the root you are. You want to keep the number of classes as low as possible, and you want to repeat yourself as seldom as possible.

For example, let's say you have three levels of navigational menus.
These three menus look different, but they also share certain characteristics. For example, they are all <ul>, they all have the same font size, and the items are all next to each other (as opposed to the default rendering of an ul). Also, none of the menus has any bullet points (list-style-type).

First, define the common characteristics in a class named menu:

div.navi ul.menu { display: ...; list-style-type: none; list-style-image: none; }
div.navi ul.menu li { float: left }

then, define the specific characteristics of each of the three menus. Level 1 is 40 pixels tall; levels 2 and 3, 20 pixels.

Note: you could also use multiple classes for this but Internet Explorer 6 has problems with multiple classes, so this example uses ids.

div.navi ul.menu#level1 { height: 40px; }
div.navi ul.menu#level2 { height: 20px; }
div.navi ul.menu#level3 { height: 16px; }

The markup for the menu will look like this:

<ul id="level1" class="menu"><li> ...... </li></ul>
<ul id="level2" class="menu"><li> ...... </li></ul>
<ul id="level3" class="menu"><li> ...... </li></ul>

If you have semantically similar elements on the page—like these three menus—try to work out the commonalities first and put them into a class; then, work out the specific properties and apply them to classes, or, if you have to support Internet Explorer 6, ID's.

Miscellaneous HTML tips

If you add these semantics to your HTML output, designers can later customize the look of web sites and/or apps using pure CSS, which is a great advantage and time-saver.

If possible, give every page's body a unique class: <body class='contactpage'> this makes it very easy to add page-specific tweaks to the style sheet:
```
body.contactpage div.container ul.mainmenu li { color: green }
```
When building menus automatically, add as much CSS context as possible to allow extensive styling later. For example:
```
<ul class="mainmenu">
 <li class="item_first item_active item_1"> First item </li> 
 <li class="item_2"> Second item </li> 
 <li class="item_3"> Third item </li> 
 <li class="item_last item_4"> Fourth item </li> 
</ul>
```
This way, every menu item can be accessed for styling according to its semantic context: Whether it's the first or last item in the list; Whether it's the currently active item; and by number.

Note that this assigning of multiple classes as outlined in the example above does not work properly in IE6. There is a workaround to make IE6 able to deal with multiple classes. If the workaround is not an option, you will have to set the class that is most important to you (item number, active or first/last), or resort to using IDs.

Tool for cleaning up CSS?

You can try CSS Tidy:

http://csstidy.sourceforge.net/

It is simple yet effective.

Cleaning up sloppy code html/css/javascript

Well first of all, you can assign multiple selectors the same rule. Something like this:

.rollover1, .rollover2, .rollover3 {
    background-image: url(http://www.placehold.it/110x88);
    height: 88px;
    width: 110px;
    opacity: 0;
    float: left;
}

Even better than that, though, you could eliminate the need for .rollover1, 2, and three and just make a .rollover class that you apply to everything.

If you need a different image for each rollover, then this would work:

.rollover1, .rollover2, .rollover3 {
    height: 88px;
    width: 110px;
    opacity: 0;
    float: left;
}
.rollover1{
    background-image: url(http://www.placehold.it/110x88);
}
.rollover2{
    background-image: url(http://www.placehold.it/110x88?2);
 }

You can do the same with your IDs.

If you're seriously looking to clean up your styles, look in to "object oriented CSS" (Note: I think the name "OOCSS" is HIGHLY misleading, but it is still good practice). Object Oriented CSS, basically changes the approach to writing CSS. Rather than saying "this CSS is for my button that is blue and has a margin of 5px" and outputting code like this:

#myBlueButton{
    background-color:#00f;
    margin:5px;
}

<button id="myBlueButton">

You write CSS like this:

.blue{
    background-color:#00f;
}
.margin5px{
    margin:5px;
}

And then your button will look like this:

<button class="blue margin5px">

This encourages seperation of concerns and symantic classes, while reducing your need for IDs and reducing the need for overly specific CSS selectors. It also allows you to easily re-use your CSS styles without having to repeat yourself.

Even better than OOCSS, though, look in to things like SASS and LESS Which allow you to write rules that will generate your CSS for you.

CSS Tidy configuration

I was able to track down the source of my problem. I had incorrectly attributed it to CSS Tidy, when something else was actually at fault. Thanks for the help.

What Is the Best Method for Tidying CSS