CSS

层叠样式表— or CSS — 是你在HTML之后应该学习的第二门技术. Whereas HTML is used to define the structure and semantics of your content, CSS is used to style it and lay it out. So for example, you can use CSS to alter the font, color, size and spacing of your content, split it into multiple columns, or add animations and other decorative features.

Learning pathway

You should really learn the basics of HTML before attempting any CSS. We'd recommend that you work through our Introduction to HTML module first — you can then learn about:

• CSS, starting with the Introduction to CSS module
• More advanced HTML modules
• JavaScript, and how to use it to add dynamic functionality to web pages

We'd recommend that you learn HTML and CSS at the same time, moving back and forth between the two topics. This is because HTML is far more interesting with CSS, and you can't really learn CSS without knowing HTML.

Before starting this topic, you should also have at least basic familiarity with using computers, and using the Web passively (i.e. just looking at it, consuming the content.) You should have a basic work environment set up as detailed in Installing basic software, and understand how to create and manage files, as detailed in Dealing with files — both are parts of our Getting started with the web complete beginner's module.

It is recommended that you work thorugh Getting started with the web before attempting this topic, however it isn't absolutely necessary; much of what is covered in the CSS basics article is also covered in our Introduction to CSS module, albeit in a lot more detail.

Modules

This topic contains the following modules, in a suggested order for working through them. You should definitely start with the first one.

Introduction to CSS

This module gets you started with the basics of how CSS works, including selectors and properties, writing CSS rules, applying CSS to HTML, how to specify length, color, and other units in CSS, cascade and inheritance, box model basics, and debugging CSS.

Styling text

Here we look at text styling fundamentals, including setting font, boldness, and italics, line and letter spacing, and drop shadows and other text features. We round off the module by looking at applying custom fonts to your page, and styling lists and links.

Styling boxes

Next up, we look at styling boxes, one of the fundamental steps towards laying out a web page. In this module we recap the box model then look at controlling box layouts by setting padding, borders and margins, setting custom background colors, images and other features, and fancy features such drop shadows and filters on boxes.

CSS layout

At this point we've already looked at CSS fundamentals, how to style text, and how to style and manipulate the boxes that your content sits inside. Now it's time to look at how to place your boxes in the right place in relation to the viewport, and one another. We have covered the necessary prerequisites so can now dive deep into CSS layout, looking at different display settings, traditional layout methods involving float and positioning, and new fangled layout tools like flexbox.

Responsive design (TBD)

With some many different types of devices able to browser the Web these days, responsive web design (RWD) has become a core web development skill. This module will cover the basic principles and tools of RWD, explain how to apply different CSS to a document depending on device features like screen width, orientation, and resolution, and explore the technologies available for serving different video and images depending on such features.

Animations and transforms (TBD)

Two of the most interesting areas of CSS are the ability to manipulate elements (e.g. moving, rotating and skewing), and smoothly animate elements (e.g. from one color or position to another.) This module explores how to implement so-called transformations and animations.

Solving common CSS problems

Use CSS to solve common problems provides links to sections of content explaining how to use CSS to solve very common problems when creating a webpage: Styling boxes,

See also

CSS on MDN

The main entry point for CSS documentation on MDN, from detailed references to advanced tutorials.

CSS reference

A comprehensive reference guide to all the many features of the CSS language — if you want to know what values a property can take, for example, this is a great place to start.