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How to Manage CSS Explosion
I intended to build my web site with consistent styles and a coherent CSS scheme. But styles have crept out of control as I fine-tune individual pages (especially the main search form).
I've already gone through the process one time of breaking down the styles and rebuilding almost from scratch, and now it looks like time to do that again. How can I be efficient about this? I'm looking for a methodology, not a software utility (though I'm open to suggestions there...unless they cost money...).
Added note: I'm using a CSS framework and it's difficult to keep padding and margin coordinated.
Added note 2: The initial responses to this post are about best practices for CSS. Let's assume I already tried to follow best practices (in fact, I did). Now it's the clean-up procedure I'm looking for.
Added note 3: As of 14 June, combining this response (which I just found) with my post below is possibly a comprehensive answer.
Closure notes:
I learned my question is too general, and for that reason I wish I hadn't posted it. (Maybe that's why it got a down-vote ... I'll never know without a comment to explain the reason.) On the other hand I got just what I needed, so I'm happy I did post it.
I'm surprised I didn't get an up-vote for my answer -- even with the priceless input by others, I think it stands up pretty well.
My acceptance is going to be based largely on the usability of the answer, from my point of view -- a point of view that is sadly unable to digest some of the more exciting and comprehensive responses.
Closed as an Exact Duplicate
I just tried posting this again (subject, body, tags) to see if SO would suggest the post "How to Manage CSS Explosion". Interestingly, it did not. I added the tag refactoring to that post.
Split your css into separate files.
Put in one file the CSS reset (if you use one)
Then create a global.css file where you will put global styles that
apply to many-all pages
Then create individual files for your individual pages
Then start styling your pages. Every time you find a style rule that is reusable on many pages make it a CSS class and put it in the global.css file. Avoid using css ID's. You will find that you more often reuse things or will reuse in the future. In this case you use of course CSS classes.
Eventually you will find out that in your global.css you will find mostly CSS classes rules and html tag rules.
In your individual page CSS files you will find specific styles for each page.
That should give you a good first level of organization in your CSS. You can try to keep this separation through the whole development process, and for releases merge the CSS files into one and minify it.
my 2p worth about css cleanup, from a a previous similar question:
Tips for cleaning and maintaining a big css file
hope that this may help you together with others' answers!
start branching the project (here I suppose that you are using a version control tool) - that will allow you to play independently with the code and tag any milestone you will reach.
format your CSS with a beautifier - it will increase readability and will help searching for specific declarations without missing any instances.
try to identify unused / redundant css and get rid of it.
you could try to make your selectors shorter (e.g. .main .foo .bar might be fine as .bar) - it will improve readability and increase the performance, but take this with a pinch of salt and be ready to go back if things start to break at every step you take.
try to eliminate, if possible, any !important - make the selector more specific if needed. A css reset could help with that if most of the !important statements were made to fix browser-specific issues, otherwise introducing a css reset now could potentially add more problems than solve them - this, if there is no css reset in your app at all.
break and regroup the css into different modules (and files if that helps) - Object Oriented CSS is a possible technique to keep things more maintainable, it works best if you start with it but it may also help you in refactoring. https://github.com/stubbornella/oocss/wiki is a valid one but there are alternatives that you can consider, like SMACSS.
After that , you may consider using a css preprocessor such as Less or Sass, allowing you to define variables and mixins (similar to functions), modularity and much more - this may end up being a very expensive task though, so evaluate carefully if this will bring you more benefits than pain.
test as much and as often as you can, consider unit tests to make sure that any changes you make don't break anything somewhere else.
Sometimes re-writing everything may end to be less time consuming than refactoring, so don't be afraid to leave things as they are if your assessment will show that refactoring will not bring enough benefits.
EDIT
Things change and evolve for good; with regards to OOCSS/SMACSS approach, I have been happily following for a while, Yandex's BEM methodology for CSS, I would like to add it as an additional recommendation to the above
The first thing I'll do is separate the CSS based on the purpose. Maybe first the general page layout (DIVs, boxes, ...), then the styling (fonts, H1/H2/.../Hn titles), then some more specialized CSS (CSS for tables, for forms, for specific components of the site).
Such a separation helps to organize the changes; if you have to change or add a font, you know you'll find it in the styling section.
If you have to change the page layout, there goes the same, and so on.
Things tend to get messy when you have "individual pages"; is their layout so different?
You probably have to abstract the common features of the pages (for example, a main content container box) as long as you can.
Then think about specializing more the layout (1-column, 2-column) and so on.
If you have a programmer background, just think about classes and inheritance, the concept - yes I know it's a totally different domain... - but the concept can be useful in designing your css.
Based on this current round of work, here is what I've got so far:
the Planning
Have a system for handling To-Do notations in your HTML and CSS. Many IDEs support this directly, or a global search function will do just fine. Besides tagging issues, you want to note priority and perhaps even functional area (but keep it simple, not a burden).
Don't start revising your code. Use your To-Do system to plan first.
Make a concise list of your overall goals.
Consider overall sylistic changes such as color or font scheme.
Review best practices for CSS. Identify areas where your approach is ineffective, or where a good approach can be applied more consistently. Examples:
Consolidate classes
Eliminate haphazard use of in-line styles
Remove styles that are unused or redundant or conflicting
Improve general consistency; apply a set of conventions
Improve units of measure
Use class and id names that reflect content rather than format
Decide how much of the browser market you want to support and how much to embrace or rely on the newest standards.
Decide if there are any new approaches you want to adopt. Examples:
Use of a reset style sheet to standardize browser presentation
Use of a CSS framework
Use of a specialized library, for example to help with forms
Dynamic CSS (I recently followed advice to use PHP to handle my CSS, so I could dynamically control my color scheme. But I returned to straight CSS, because I like the presentation of CSS code in my IDE and the hybrid method messed that up.)
Review your list of goals and decide which should be pursued now. Any large-scale change should be treated as separate, if possible. If your column layout is a mess, it's not the time to learn how CSS can elegantly replace your javascript. The same goes for best practices, stylistic changes, etc.
If you have your CSS files configured for speed (for example, compacted footprint or all CSS in a single file), change that. Break the code into a human-managable format. Later when you're finished, try benchmarking to see if the more legible version is also efficient enough for production use.
Submit your CSS to a validator. Note any violations you want to fix.
Find instances of in-line styles in your HTML (search for the style attribute). Note any that should be moved to a style sheet.
the Work
Follow your To Do manager. Make common-sense back-ups. As you go, test your work on several browsers.
If you are into regular expressions, be warned: regex is often not effective or safe for rewriting CSS. (Not as hazardous as for HTML, but still). Regex may be useful sending CSS changes into the HTML, but again be careful.
If you have a lot of tweaks to margins and padding, try globally resetting all of them to 0px (okay, use regex here). Then systematically build them back up. You can resolve a lot of confusions this way. Of course, don't include any library or framework style sheets in this process.
Again, submit your CSS to a validator.
I see people has already suggested using approaches like OOCSS etc., so I'm going to offer a different/additional line of thought. I believe that the problem lie deeper than within your CSS and the way you write it. I believe the reason your CSS gets out of hand is this quote from your question:
... as I fine-tune individual pages ...
That makes me think that the problem much lie within your design, rather than you CSS, so let me elaborate a little bit on that. In my opinion a great design is a design that doesn't have to be customized for each individual page - and there are several reasons for that. The main reason is, as you've mentioned yourself, your CSS get out of control. Small tweaks and fixes on individual elements, depending on where they are placed, often leads to a mess that is a pain to maintain and work with. There is also a usability-reason in play here. I believe a UI becomes easier to use if the user is familiar with the UI and recognize herself from page to page, without to much variation. Of course you could have some element that isn't present on each page, or that vary somewhat between pages, but I always strive to keep them at a minimum.
My suggestion is therefor that if you intend to rewrite your CSS, which is time-consuming and hard work anyway, then why not go over and re-evaluate your design at the same time. You will probably find that there are elements that you can modify so that they look the same. Make it a goal to get rid of as many UI-elements as possible, without compromising the design. When you've unified the design as much as possible, then it is time to refactor your CSS, and maybe even your markup?
At this point, it might be better to get rid of all your CSS and start fresh. If you continue on your old code, it is easy to get lazy and get stuck with some of your old less efficient code.
For the coding, I believe the other answers contain lots of good recommendations and best practices. I would personally vote for OOCSS, a new discovery for myself as well, but it has improved the way I structure my CSS a lot. So have a look at that! That will also help you think in terms of reusing elements and the CSS for them, which goes a long way for simplyfing your CSS.
This answer is in regard to the note;
"I'm using a CSS framework and it's difficult to keep padding and margin coordinated." only.
Using a css pre-processor will solve this problem.
Because css has no way to assign inheritance and therefore we have to repeat 'margin:10px' over and over.
with a pre-processor you just do
#margin {10px}
#padding {10px}
then
.mySelector{
margin: #margin;
padding: #padding;
}
For the broader question rethink/simplify your design as your css is directly proportional to the complexity of the design and there is not much you can do about that.
See also, http://www.stubbornella.org/content/2011/04/28/our-best-practices-are-killing-us/
This is more advice about making your css maintainable than the Q of how to manage the process.
I create a bunch of separate css files each narrowly tailored to a specific attribute (colors, fonts, margins, corners) or feature (nav, form). Then I use a compile phase to combine and minify these files into one or more files to be sent to the client. I do this during my built/test process, but it could be done dynamically by a CGI script.
Before adopting a pre-compiler, consider the often-overlooked multiple-selector syntax:
element,
otherlement
{
margin:10px;
}
In this example, whenever I want an element to have a 10px margin, I add it to the list. I separate different sets of attributes this way - I may list the same element 5 times in my css - associating it with 5 different sets of attributes.
Also don't overlook adding various classes to the body tag to create OO-like inheritance - say you have 3 main sections of your site - assign the body tag a class based on those sections. Likewise, if you have 1000 product pages, you can give the body tag a class like "product485" and then create styles that apply just to that page. For example:
h1 {
margin: 10px;
}
.product485 h1,
.product484 h1
{
margin: 5px;
}
.contact h1 {
margin: 15px;
}
This might all be in a file called "margins.css" which specifies only margins.
Consider the following three scenarios...
Scenario A
#import "reset.css";
/* ... */
p {margin:1em 0;}
/* ... */
p#copyright {margin:0; padding:10px;}
In Scenario A, a generic rule is applied to all <p> elements that gives it top and bottom margins, so that the paragraphs are properly spaced when used in the HTML. But, by doing so, this causes cases where a <p> element now needs its generic margins removed for decorative purposes, e.g. the Copyright at the foot of the document must have no margins.
Scenario B
#import "reset.css";
/* ... */
div.content_body p,
div.sidebar_body p {margin:1em 0;}
/* ... */
p#copyright {padding:10px;}
In Scenario B, it is assumed that <p> elements don't need top and bottom margins unless explicitly defined. Here the Content and Sidebar elements will need well-spaced paragraphs
Scenario C
#import "reset.css";
/* ... */
p.spaced {margin:1em 0;}
/* ... */
p#copyright {padding:10px;}
In Scenario C, only <p> elements with a class spaced will have top and bottom margins applied.
Questions:
Which is the better scenario to use, and more importantly why?
What impact does each scenario have on:
browser CSS performance
CSS weight and maintainability
the proliferation of UI defects
If you had to add a new widget that needed flowing paragraphs, which scenario would be better for you?
Thanks!
I try to follow the principle that unadorned selectors (like "p" by itself) should provide reasonable defaults, and then use more specific selectors to override those defaults. I think this is best represented by Scenarios A and B.
If the markup is simple, and there exists a good, global default, then my stylesheets look like Scenario A.
If the markup is less simple, or global defaults are hard to define, then my stylesheets look more like Scenario B.
I try to avoid Scenario C if possible. I want it to be super easy for me (or someone else) to add new content 6 months later. I find that:
The fewer specialized classes there are, the easier it is to "fall into the pit of success" because the simplest thing you write (<p>Whatever</p>) will just work.
The more specialized classes there are, the greater the chance that you'll need to practice copy/paste programming to maintain consistent markup usage.
CSS works better when classes are semantic and describe what a piece of content is than when they are presentational and describe how content should be displayed. Scenario C is an example of presentational styling, which is only marginally better than inline styles.
Generic first because it's better to allow all first and then block fews later. :)
It totally depends on the design of your site.
If most paragraphs on the site should have margins, but a couple don’t, then the approach in A would require the least code, and would thus probably result in lower CSS weight and more maintainability.
But if only paragraphs within your content and sidebar areas require margins (or there aren’t many outside them that do), then the approach in B is a better idea.
As for the approach in C, my main worry with that would be how the HTML for the site is generated. If it’s generated by a back-end system, that system will have to know which paragraphs should be spaced, and which shouldn’t. That’s extra complexity for the system, or its users, to deal with.
For the specific example of paragraphs, I’ve often ended up with something like B. It’s easy to assume that paragraphs should have some nice, decent styling that would make, say an article nice to read. But if you look at most modern websites, most of what’s on the page isn’t content like that: it’s menus and sidebars and special little things. Now, that may not be great, design-wise, but if you’re implementing a design like that, B is the way to do that with less code, and less code generally means lower weight, easier maintainability, and fewer defects.
Personally I prefer scenario A. I find if you do things this way you can make the most of the cascade. The question you have to ask yourself though is "what is the sensible default?" Meaning is it more likely that a p will need spacing, or more likely that it wont. That should help you determine what your blanket defaults should be. Generally speaking the answer to this question is going to put you in line with scenario A.
D None of the above
#import ""; // don't need this
p { } // don't need this
ul#footer li { padding: 10px }
Browsers manufacturers know an awful lot about their technology in particular and about typography and layout in general. A 'reset' is a great way of disposing of all that aggregated experience. Browser default behaviour is a good thing and should only be overwritten in exceptional circumstances. Different browsers do look a bit different. This is not a bad thing. See: http://dowebsitesneedtolookexactlythesameineverybrowser.com/
A copyright citation is not a paragraph of text. It is probably one among several items in a list of supporting information about the page in question. If not, it is a list of one.
I didn't see anything on here about it with a quick search, if there is let me know.
Here is an example of a CSS selector I'd write.
div#container div#h h1 { /* styles */ }
div#container div#h ul#navi { /* styles */ }
div#container div#h ul#navi li.selected { /* styles */ }
I write all my CSS like. This allows me to stop from having styles floating around and I can technically re-use the same class name easily. For instance, I might use .selected on multiple elements across the site.
I also specify the element type (div, ul, etc) before the class/id unless the style is used for multiple elements. I also specify the element before id's even though there will only ever be one id because it allows me to know the element easily when reading my CSS. For instance I'll know right off the bat that em#example will most likely have a font-style of italic.
This isn't a question about CSS formating, it's about writing selectors.
I'd love to hear opinions on this approach, as I've used it for years and I'm reevaluating my stying.
Although it's somewhat off topic I also write my selectors like this for selector libraries (like jQuery for instance). Although I haven't looked into jQuery's internals to see if there is performance issue with specifying the element with an ID.
I think it really depends on what the selector is for.
Almost every site has one or a few style sheets that "skin" the site - fonts, text colour, link colour/hover, line spacing, and so on, and you don't want these selectors to be very specific. Similarly, if you have a component or element that's reused in many pages and always needs to look the same - like let's say the tags right here on SO - then it's going to be a pain to maintain if you use selectors based on the ID.
I would always use the ID in the selector if it refers to a specific element on a specific page. Nothing's more frustrating than trying to figure out why your rules don't seem to be working because of a conflict with some other rule, which can happen a lot if everything is classes. On the other hand, I think that nesting the IDs as you are (#container #h) is redundant, because the purpose of an ID is to be unique. If you have more than one element with the same ID on the same page then you can end up with all sorts of problems.
It does make the CSS slightly easier to understand when your selectors provide some idea of the "structure" that's being represented, but, to be honest, I think that goes against the idea of separation of concerns. The #navi might be moved outside the #h for perfectly legitimate reasons, and now somebody has to update the style sheet for #navi, even though nothing about it has changed.
A bit subjective as Darrell pointed out but that's my two cents.
While the question is a little subjective I have to say I agree with your thinking. I think defining the element before the selector is clearer when reading the code and it is less error prone.
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Closed 10 years ago.
Are there any good CSS coding style/standards?
Here is a good one:
http://www.phpied.com/css-coding-conventions/
But the important thing is to pick something and stick with it for consistency.
I agree with most of the points at Andrew Hare's link, but I strongly believe
.class-name {
color: green;
}
is inferior to:
.class-name
{
color: green;
}
on the grounds that:
.class-name, .class-name2 {
color: green;
}
or:
.class-name,
.class-name2 {
color: green;
}
are considerably less obvious to grep or read than:
.class-name,
.class-name2
{
color: green;
}
There's no standard standard, as it were. There are most certainly plenty of in-house standards and conventions. And there are certainly known best practices.
I stick to the following:
Structure your CSS according to it's purpose
That may involve separating out CSS concerns into different files (layout.css, colors.css etc). This may just as well involve clearly dividing up a single CSS file into clear sections along the same lines.
Be as specific as possible
Selectors have differing weights. ID-based selectors are more specific than class-based selectors. Chained selectors (e.g. body div#container div#content p) are very specific indeed.
Start out being as specific as you can, even if it appears you're being too specific. It's quite easy, later down the line, to merge together two very specific style definitions by removing one and making the other less specific.
A style definition with loose specificity may target elements you did not intend in ways that are not immediately apparent or obvious. I think this is the most common cause of CSS frustrations ("Why on earth will this div not let me set a top margin?")
Always specify every single style you wish to apply for a given defintion
For example, if you want all your paragraphs to have pink text, set the text colour to pink and also set the margins/padding/background colour/font and so on.
Don't rely on browser defaults to be suitably consistent. Certainly for the most commonly used elements the main browsers tend to use very similar if not identical default styling.
If you set all the relevant styles yourself you know what the end result should be.
If you only set those styles that are most immediately obvious, the end result will be (most likely) a combination of the browser defaults and your styles. This will eventually catch you out at some point. I think this is the second most common cause of CSS frustrations.
Use ids for styling unique elements
It's generally a good idea to apply an id attribute to any unique element that is going to be interacted with in any way. For CSS this will let you apply suitably specific styles more easily.
Use an id on a unique page
Pages that are significantly different in style and layout to the majority (homepage, search results, 404) should have an id on the body element. This gives you the specificity you need to ensure that your careful homepage styling doesn't get affected by styles you later apply to some internal content page.
Pretty coding style VS site speed
I've been working with pretty huge CSS files, and found out some pretty interesting things that I've never read about before.
#import
One thing is using #import. That's actually a bottleneck - by going away from using #import completely, the site got a lot more snappy.
#every .style { in one line }
When the browser reads a document, it reads line by line, so by switching from my pretty coding style to this, I accomplished 2 things;
A even more snappy site
Less scrolling, better overview. Why? Cause I first scroll down to find the style I'm going to work with, then it's all in the same line and it's not hard to scroll your eyes along the line to find what you're looking for.
The main good coding style is to actually separate css files according to their goals.
See Progressive Enhancement.
That way, whatever coding convention you will choose, you will have consistent and manageable separate css files... easier to debug.
When I code in CSS:
In first part I write the class and id
In last part I write the general element (p, font, etc) because the class and id have more importance for inheritance
I write comment if I want a particular behaviour with IE or with MoSE Browser
You can see some example in CSS Zen Garden
Generally I insert the most important elements over the other: if there's
p.important{/*features of a class*/}
p {/*features of a general element */}
Reading the CSS file I know the format rules before about the most particular elements, after the rules about the most general elements.
It's an habit in programming Java.
Put your css rules (ex: "color: red;") in alphabetical order and also put your selectors (ex: "div { color: red; }") in order they appear in your markup. Separate code for structure from skin.
Just from experience I used to write quite long CSS style sheets. Now my style sheets typically are half a page.
So keep it simple(KISS), line based (greppable) and keep it compact (use font: instead of font-size etc etc.).
Also I highly recommend using CSSlint to check your code for fluff.
Check Sass out. It's a template language for CSS that makes your source code DRY:er and mucho easy to read. Even if you're not using ruby you can use it for this task and automate the building of your css files from Sass source. And there are probably Sass implementations in other languages too.
There's probably loads. At our work we use the following:
/* =div a comment about my div */
div#mydiv {
border:1px solid #000;
}
The =div allows us to search against all div elements by using the search functionality. There's loads more though, I've used many different variations of this in the past.
In addition to what others said, remember that the C stands for 'Cascading', i.e. subelements inherit from top level elements. Sound simple and straight away. But I have often seen CSS files that contain redundant declarations, e.g. for font styles. This makes a CSS more complex and hard to maintain.
So before you add something to your CSS make sure that it is not redundant, i.e. check parent elements and remove redundant declarations from children.
Given this you should organize your CSS in a way so that high level elements (like declarations for the body class) are mentioned first and more specialized elements last.
This might also be helpful, a few tips to keep your CSS styles DRY - as in "Don't Repeat Yourself" link text
I will strongly recommend looking at Less: http://lesscss.org
While not really a standard, it has been gaining a lot of momentum recently. Less is css extension that runs in the browser bringing variables and functions into the language and therefore allowing templating.
If I have class names such as "left", "right", "clear" and xhtml like
Continue
With CSS like
.right {
float: right;
}
I know it's not a semantic name, but it does make things much easier sometimes.
Anyway, what are your thoughts?
I don't think that's a very good idea. Now when you (or a future maintainer) go to change your website layout, you'll either have to change .right to {float:left;} (obviously a bad idea) or go through all your HTML files and change right to left.
Why do you want that particular link to be floated right, and the other .continueLink's not to? Use the answer to that question to choose a more descriptive class name for that link.
css is about presentation of the structure of your html page.
Meaning its classes should represent the structure of the document ('article', 'extra-links', 'glossary', 'introduction', 'conclusion', ...).
You should avoid any class linked to a physical representation ('left', 'right', 'footnotes', 'sidenotes', ...), because, as the Zen Garden so clearly illustrates, you can decide to place any div in very different and various ways.
The purists will say don't do it, and the pragmatists will say it's fine. But would the purists define .right as float: left?
It might be advisable to avoid names that are the same as values in the CSS specs to avoid confusion. Especially in situations where multiple developers work on the same application.
Other than that I see no problem. I would qualify the right or left name like this: menuleft, menuright etc.
Being a purist, I say no don't do it. For reasons mentioned earlier.
Being a pragmatist, I just wanted to say that never have I seen website rework that involved pure html changes without css, or pure css without html, simply because both parts are being developed with the other in mind. So, in reality, if somebody else would EVER need to change the page, I bet my salary they will change both html and css.
The above is something that collegue purists around often tend to ignore, even though it's reality. But bottom line; no, avoid using a className such as "right". :-)
.right and other classes like that, certainly makes it quick to write create a tag with a float:right rule attached to it, but I think this method has more disadvantages than advantages:
Often a class-style with a single float:right; in it will lack something, your example wil only float right if the other class rule contains a display:block in it, since an "a" tag is not a block level element. Also floating elements more often than not needs to have width an height attached. This means that the code in your example needs additional code to do what it says, and you have to search in two places when you have to change your css.
I tend to style my html by dividing the page into different div-tags with unique id's, and then styling elements in these div by inheritance like this.
div#sidebar { float:right; width:200px; }
div#sidebar ul { list-style-type:none; }
This makes it possible to partition my css files, so that it is easy to find the css-code that styles a particular tag, but if you introduce .right and other classes you are starting to disperse the rules into different areas of the css file, making the site more difficult to maintain.
I think the idea of having a very generic classes is born from the wish of making it possible to change the entire layout of the site by changing a couple of rules in a stylesheet, but I must say that in my 8 years of website development with 30+, different sites under my belt i haven't once changed the layout of a website and reused the HTML.
What I have done countless times is making small adjustments to regions of pages, either due to small changes in the design or to the introduction of new browsers. So I'm all for keeping my css divided into neat chunks that makes it easy to find the rules I am looking for, and not putting the code in different places to achieve a shorter stylesheet.
Regards
Jesper Hauge
Yeah, semantically speaking it is wrong, but, for example, there are times when I'm positioning images within a block of body copy and I'll give them the class "right".
Maybe "alt" is a more suitable class name.