Screen reader

The heading levels (1-6) are often considered a way of describing and determining the “importance” of a heading, with h1 being the most important.

For a readable interface, it's important to use visual cues to group or separate content to show which content relates to other content.

When positioning elements using CSS, it's possible to place them in a position that does not reflect their location in the source order. This can have unexpected side effects for keyboard-navigation users.

Icon fonts are a popular and effective method for providing scalable symbols that can be used to label controls and provide graphical information. The information provided by icons also needs to be available to people who can’t see them.

Each image requires alternative text that is equivalent to the information it conveys, unless the image is purely decorative and provides no useful information. You need to be careful about what value you give the alt attribute.