HTML5 Boilerplate homepage | Documentation table of contents

The CSS

HTML5 Boilerplate's CSS includes:

Normalize.css
Useful defaults
Common helpers
Placeholder media queries
Print styles

This starting CSS does not rely on the presence of conditional class names, conditional style sheets, or Modernizr, and it is ready to use no matter what your development preferences happen to be.

Normalize.css

In order to make browsers render all elements more consistently and in line with modern standards, we include Normalize.css — a modern, HTML5-ready alternative to CSS resets.

As opposed to CSS resets, Normalize.css:

targets only the styles that need normalizing
preserves useful browser defaults rather than erasing them
corrects bugs and common browser inconsistencies
improves usability with subtle improvements
doesn't clutter the debugging tools
has better documentation

For more information about Normalize.css, please refer to its project page, as well as this blog post.

Useful defaults

Several base styles are included that build upon Normalize.css. These styles:

provide basic typography settings that improve text readability
protect against unwanted text-shadow during text highlighting
tweak the default alignment of some elements (e.g.: img, video, fieldset, textarea)
style the prompt that is displayed to users using an outdated browser

You are free and even encouraged to modify or add to these base styles as your project requires.

Common helpers

Along with the base styles, we also provide some commonly used helper classes.

`.hidden`

The hidden class can be added to any element that you want to hide visually and from screen readers. It could be an element that will be populated and displayed later, or an element you will hide with JavaScript.

`.visuallyhidden`

The visuallyhidden class can be added to any element that you want to hide visually, while still have its content accessible to screen readers.

`.invisible`

The invisible class can be added to any element that you want to hide visually and from screen readers, but without affecting the layout.

As opposed to the hidden class that effectively removes the element from the layout, the invisible class will simply make the element invisible while keeping it in the flow and not affecting the positioning of the surrounding content.

N.B. Try to stay away from, and don't use the classes specified above for keyword stuffing as you will harm your site's ranking!

`.clearfix`

The clearfix class can be added to any element to ensure that it always fully contains its floated children.

Over the years there have been many variants of the clearfix hack, but currently, we use the micro clearfix.

Media Queries

HTML5 Boilerplate makes it easy for you to get started with a mobile first and responsive web design approach to development. But it's worth remembering that there are no silver bullets.

We include placeholder media queries to help you build up your mobile styles for wider viewports and high-resolution displays. It's recommended that you adapt these media queries based on the content of your site rather than mirroring the fixed dimensions of specific devices.

If you do not want to take the mobile first approach, you can simply edit or remove these placeholder media queries. One possibility would be to work from wide viewports down, and use max-width media queries instead (e.g.: @media only screen and (max-width: 480px)).

For more features that can help you in your mobile web development, take a look into our Mobile Boilerplate.

Print styles

Lastly, we provide some useful print styles that will optimize the printing process, as well as make the printed pages easier to read.

At printing time, these styles will:

strip all background colors, change the font color to black, and remove the text-shadow — done in order to help save printer ink and speed up the printing process
underline and expand links to include the URL — done in order to allow users to know where to refer to
(exceptions to this are: the links that are fragment identifiers, or use the javascript: pseudo protocol)
expand abbreviations to include the full description — done in order to allow users to know what the abbreviations stands for
provide instructions on how browsers should break the content into pages and on orphans/widows, namely, we instruct supporting browsers that they should:
- ensure the table header (<thead>) is printed on each page spanned by the table
- prevent block quotations, preformatted text, images and table rows from being split onto two different pages
- ensure that headings never appear on a different page than the text they are associated with
- ensure that orphans and widows do not appear on printed pages

The print styles are included along with the other css to avoid the additional HTTP request. Also, they should always be included last, so that the other styles can be overwritten.

dmd-git-demo/doc/css.md