这里有一些很棒的材料，有些人已经花了很多时间来回答这个问题，但是当涉及到单独或单独的样式表时，我会使用单独的文件进行开发，然后在部署时将所有在站点上使用的通用css合并到一个文件中。

这样你可以两全其美，提高性能(从浏览器请求的HTTP请求更少)，并在开发时分离代码关注点。

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。

这里有一些很棒的材料，有些人已经花了很多时间来回答这个问题，但是当涉及到单独或单独的样式表时，我会使用单独的文件进行开发，然后在部署时将所有在站点上使用的通用css合并到一个文件中。

这样你可以两全其美，提高性能(从浏览器请求的HTTP请求更少)，并在开发时分离代码关注点。

你应该看看边界元法。

理论

BEM试图提供一组用于组织和命名css选择器的指令，以使选择器更具可重用性和模块化，并避免选择器之间的冲突，这种冲突通常会导致意大利面条式的代码和特定的问题。

如果正确使用，它实际上有一些非常积极的影响。

当样式被添加到元素中时，它们的作用是您所期望的 样式不会泄露，并且只影响它们所添加的内容 样式与文档结构完全解耦 不同的风格不需要被强迫凌驾于彼此之上

BEM works well with SASS to bring an almost object oriented style to CSS. You can build modular files, that handle the display of a single UI element and contain variables, such as colours and 'methods' such as how internal elements are handled. While a hardcore OO programmer might balk at this idea, in fact, the applied concepts bring in a lot of the nicer parts of OO structures, such as modularity, loose coupling and tight cohesion and context free re-usability. You can even build in a way that looks like an encapsulated object by using Sass and the & operator.

更多来自Smashing杂志的深入文章可以在这里找到;还有一个来自CCS Wizardry的Harry Roberts(任何参与css的人都应该读一下他的书)。

在实践中

我已经用过它几次了，还用过SMACSS和OOCSS，这意味着我也可以对它们进行比较。我也在一些大混乱中工作过，通常是我自己没有经验的创作。

当我在现实世界中使用BEM时，我用一些额外的原则来增强这种技术。我利用实用工具类-一个很好的例子是包装类:

.page-section {
    width: 100%;
}
@media screen and (min-width: 1200px) {
    margin: 0 auto;
    width: 1200px;
}

我也有些依赖于级联和特异性。在这里，BEM模块将是.primary-box，而.header将是特定重写的上下文

.header {
  .primary-box {
    color: #000;
  }
}

(我尽我最大的努力使所有的东西都是通用的和上下文无关的，这意味着一个好的项目几乎所有的东西都在可重用的模块中)

我想说的最后一点是，无论你的项目看起来多么小，多么简单，你都应该从一开始就这么做，原因有二:

项目越来越复杂，所以打下良好的基础是很重要的，包括CSS 即使是一个看起来很简单的项目，因为它是建立在WordPress上的，JavaScript很少，但在CSS中仍然非常复杂——好吧，你不需要做任何服务器端编码，所以这部分很简单，但是宣传册前端有20个模块和每个模块的3个变体:你有一些非常复杂的CSS !

Web组件

在2015年，我们开始关注Web组件。我对这些还不太了解，但它们希望将所有前端功能放在自包含的模块中，有效地尝试将各种原则从BEM应用到前端作为一个整体，并将分散但完全耦合的元素(如DOM片段、Js (MVC)和CSS)组合在一起，这些元素都构建相同的UI小部件。

通过这样做，他们b将解决css中存在的一些原始问题，我们试图用BEM等东西来解决这些问题，同时使其他一些前端架构更加合理。

这里有一些进一步的阅读材料，还有一个框架聚合物，非常值得一看

最后

我也认为这是一个优秀的、现代的css最佳实践指南——专门为防止大型css项目变得混乱而设计。我尽量遵循其中的大部分。

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.

我已经使用级联样式表(CSS)超过20年了。所以下面是我的解决方案来帮助你:

ALWAYS use External CSS via a <link> tag. External CSS is far superior to "embedded" <style> and "inline" element styles <span style="color:blue;">my text</span> simply because external styles downloaded to the browser are cached for every page in your website and affect all web pages, not just one. Consider moving all those styles sprinkled throughout your website to CSS classes in your sheets. Make sure you add selectors to increase their weight in cases where they might have cascaded over earlier inherited styles. Note: Many JavaScript API's like Angular and others use embedded CSS which means they are slower and have to reload CSS every refresh or revisit to the site. Bad design! ALWAYS use a "Reset" Style Sheet for all your basic HTML Elements. Most CSS packages like Bootstrap and others come with a reset or reboot sheet. These restyle all your HTML element selectors so they look decent across all browsers and user agents. This saves you the nightmare of having to restyle and customize design across basic elements like form controls, layouts, text, etc. I wrote my own "reset" sheet years ago. I am going to post it on GitHub under "Universal CSS Framework" soon if you would like mine. Works in all the old and new browsers. Remember, all text-based styles cascade and inherit naturally down through the sites elements! So, you should rarely need to repeat font styles, line-heights, etc. Most young developers forget this. Text-based styles are inherited down the HTML tree so only have to be written one time in a parent. Often the <body> element is the best placed to set basic font styles, etc. Because of #3 you do NOT need CSS precrocessors like SASS to reorganize or manage your style sheets. Stay away from these third-party dependencies. CSS can be written to inherit or cascade styles through the site so you do not have to repeat the same font styling or properties across CSS classes, etc. Group your Block Level/Layout styles that control design. Use ID selectors (#myid) on top level HTML blocks to separate sections and use those in CSS selectors to manage items specific to that page or website section (#main .someclass {...}). These have the advantage that they are easy to track and easy to segregate, but ID selectors have very high selectivity or weight. ID selectors have a 1-0-0 or 100 weight over class which has 0-1-0 or 10 weight. This prevents any later style shifts from damaging your previous custom styles in specific protected sections. Design all CSS around a Single CSS Class that can be Reused. Avoid attaching more element and chains of classes in CSS selectors until you absolutely need to override a common shared class with a custom one. Example: .articlelink{...} would be the shared universal style everyone can access. .block1 .area2 .articlelink{...} would allow you to create a custom version throughout a section without creating a new class or changing the HTML. Use CSS Comments! /* My New Styles */ ...followed by blocks of related CSS or just use comments to explain what is not intuitive in your code. If you have big projects, have each developer write their own custom CSS sheets for their sections, but inherit the main site style sheets. First, make sure all sections of the website link to your basic reset and base site sheets first. This allows basic element styles, font settings, layout, page design, forms, and colors to be enforced by the base sheets first so developers only add new styles needed rather than reinventing the same wheel. As you update the base sheets all developers inherit, those appear naturally across all sections of the project with no effort, and the teams can see those instantly.

Remember, you are working with cascading style sheets, not style sheets! That means most text-based styles are designed to inherit from all the parent elements, then cascade those same styles down into your trees of HTML across thousands of pages with no extra code. Most new web developers fail to grasp the simplicity of CSS, so struggle with SASS and other tools to fix it. It just is not needed. CSS was designed this way over 20 years ago by very smart people that solved all these issues for you.

如果你真的开始以正确的方式使用CSS，你会发现你可以删除大部分样式，SASS，最小化，以及其他外部例程和你的网站曾经使用过的额外代码，同时享受CSS的级联效果，这些效果在很久以前就被设计为使最小代码成为可能。

<html>
  <body style="color:blue;">
    <main>
      <section>
        <div>
          <div>
            <div>
              <p>hello blue world</p>
            </div>
          </div>
        </div>
      </section>
    </main>
  </body>
</html>

和平