合理CSS的核心原则，摘自CSS重构:从仅追加到模块化CSS

Write in SASS. You'd be insane to forego the advantages of variables, mixins, and so on. Never use an HTML ID for styling; always use classes. HTML IDs, when used correctly, appear only once in the whole page, which is the complete opposite of re-usability — one of the most basic goods in sensible engineering. Moreover, it's really hard to override selectors containing IDs and often the only way to overpower one HTML ID is to create another ID, causing IDs to propagate in the codebase like the pests they are. Better to leave the HTML IDs for unchanging Javascript or integration test hooks. Name your CSS classes by their visual function rather than by their application-specific function. For example, say ".highlight-box" instead of ".bundle-product-discount-box". Coding in this way means that you can re-use your existing style-sheets when you role out side-businesses. For example, we started out selling law notes but recently moved into law tutors. Our old CSS classes had names like ".download_document_box", a class name that makes sense when talking about digital documents but would only confuse when applied to the new domain of private tutors. A better name that fits both existing services — and any future ones — would be ".pretty_callout_box". Avoid naming CSS classes after specific grid information. There was (and still is) a dreadful anti-pattern in CSS communities whereby designers and creators of CSS frameworks (cough Twitter Bootstrap) believe that "span-2" or "cols-8" are reasonable names for CSS classes. The point of CSS is to give you the possibility to modify your design without affecting the markup (much). Hardcoding grids sizes into the HTML thwarts this goal, so it is advised against in any project expected to last longer than a weekend. More on how we avoided grid classes later. Split your CSS across files. Ideally you would split everything into "components"/"widgets" and then compose pages from these atoms of design. Realistically though, you'll notice that some of your website pages have idiosyncrasies (e.g. a special layout, or a weird photo gallery that appears in just one article). In these cases you might create a file related to that specific page, only refactoring into a full-blown widget when it becomes clear that the element will be re-used elsewhere. This is a tradeoff, one that is motivated by practical budgetary concerns. Minimise nesting. Introduce new classes instead of nesting selectors. The fact that SASS removes the pain of repeating selectors when nesting doesn't mean that you have to nest five levels deep. Never over-qualify a selector (e.g. don't use "ul.nav" where ".nav" could do the same job.) And don't specify HTML elements alongside the custom class name (e.g."h2.highlight"). Instead just use the class name alone and drop the base selector (e.g. the previous example should be ".highlight"). Over-qualifying selectors doesn't add any value. Create styles for HTML elements (e.g. "h1") only when styling base components which should be consistent in the whole application. Avoid broad selectors like "header ul" because it's likely that you have to override them in some places anyway. As we keep saying, most of the time you want to use a specific, well-named class whenever you want a particular style. Embrace the basics of Block-Element-Modifier. You can read about it for example on here. We used it quite lightly, but still it helped us a lot in organising CSS styles.

我可以建议少CSS动态框架吗

它类似于前面提到的SASS。

它帮助维护每个父类的CSS。

E.g.

 #parent{     
  width: 100%;

    #child1
    {    
     background: #E1E8F2;    
     padding: 5px;    
    }

    #child2
   {
     background: #F1F8E2;
     padding: 15px
   }
 }

它的作用: 将width:100%应用于#child1和#child2。

此外，#child1特定的CSS属于#parent。

这将导致

#parent #child1
{
 width: 100%;
 background: #E1E8F2;
 padding: 5px;
}

#parent #child2
{
 width: 100%;
 background: #F1F8E2;
 padding: 15px;
}

我建议你看看“指南针风格”CSS框架。

以下是4个例子:

CSS约定/代码布局模型 在编写我的第一个样式表时，我应该遵循哪些CSS标准? 整理CSS的最佳方法是什么? 最佳实践- CSS样式表格式

在所有4个问题上，我的回答都包含了下载并阅读Natalie Downe的PDF CSS系统的建议。(PDF包含了大量幻灯片上没有的注释，所以请阅读PDF!)注意她对组织的建议。

四年后，我想说:

Use a CSS pre-processor and manage your files as partials (I personally prefer Sass with Compass, but Less is quite good as well and there are others) Read up on concepts like OOCSS, SMACSS, and BEM or getbem. Take a look at how popular CSS frameworks like Bootstrap and Zurb Foundation are structured. And don't discount less popular frameworks - Inuit is an interesting one but there are plenty others. Combine/minify your files with a build step on a continuous integration server and/or a task runner like Grunt or Gulp.

很多时候，我看到有人把文件分成几个部分，在部分之间加上标题注释。

类似的

/* Headings and General Text */

.... stuff here for H1, etc..

/* Main page layout */

.... stuff here for layout page setup etc.

它工作得很好，可以让你很容易回头看看你正在做什么。

我的回答是高水平的，针对你刚才提到的高水平的关切。也许你可以通过一些低级的组织技巧和调整来使它更漂亮，但这些都不能解决方法上的缺陷。有几个因素会影响CSS的爆炸。显然是网站的整体复杂性，但还有像命名语义、CSS性能、CSS文件组织和可测试性/可接受性等问题。

在命名语义方面，您似乎走在了正确的道路上，但还可以更进一步。重复出现在站点上而没有进行结构修改的HTML部分(称为“模块”)可以被视为选择器根，从那里您可以相对于根确定内部布局的范围。这是面向对象的CSS的基本原则，您可以在Yahoo工程师的演讲中阅读/观看更多关于它的内容。

需要注意的是，这种干净的方法可能与性能问题相反，它倾向于基于id或标记名的短选择器。找到平衡取决于你，但除非你有一个庞大的网站，这应该只是一个指南在你的脑后提醒你保持你的选择器简短。这里有更多关于性能的信息。

最后，您将为整个网站使用一个CSS文件，还是多个文件(单个基本文件用于每个页面或-section文件)?单个文件对于性能来说更好，但是对于多个团队成员来说可能更难理解/维护，并且可能更难测试。对于测试，我建议您使用一个CSS测试页面，其中包含所有受支持的CSS模块，以测试冲突和意外级联。

或者，您也可以采用多文件方法，将CSS规则作用于一个页面或一个部分。这需要浏览器下载多个文件，这是一个性能问题。您可以使用服务器端编程动态地指定和聚合(并缩小)CSS文件到单个文件中。但是，由于这些文件是分开的，对它们的测试也是分开的，因此可能会在页面/部分之间引入不一致的外观。因此测试变得更加困难。

由你来分析客户的具体需求，并相应地平衡这些问题。