Typography refresh

Goals
Type is a core visual element of Wikipedia's language.[clarification needed] The (opt-in) typography update is based on these needs.

Readability: Typefaces must be legible and readable at all sizes. Type as an element must help differentiate interface from page content.

Accessibility: Dyslexia and visual impairments must not get in the way of access. We must enable access for users with impairments.

Availability: All typefaces we use must be already available, or made available. Any selections must degrade gracefully across devices and platforms (Mac OS X, Windows, Linux, mobile platforms).

Consistency: A consistent visual experience across desktop and mobile.

Font changes
Among other things, some changes regarding fonts choices are proposed: see the /Font choice/ subpage where our current understanding of issues, goals and solutions is being summarised.

Key changes
Key changes as part of this will include: serif typefaces for headings, sans serif for body copy & marginal reduction of type size in navigational elements.

Headings font-family: Georgia, Times, serif;

Body copy font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;

Serif headings have been tested on Wikipedia mobile and have received a positive response.[clarification needed] With applying these changes to desktop, we are aiming for consistency between desktop and mobile styles. Georgia and Helvetica are fonts optimized for the web. Free and open-source systems often substitute free fonts for proprietary names mentioned earlier in the font stack, particularly for the names "Times" and "Helvetica". Arial is available on nearly every computer and operating system while being a screen-friendly typeface. As a final fallback serif and sans-serif use your browser or operating system's default font.

We continue to adjust these font stacks. in 1.23wmf18 includes the F/OSS fonts "Linux Libertine" for headings and Arimo/"Liberation Sans" for body text: These fonts will be preferred if they are installed on your computer. Also see Typography refresh/Font choice/Test.
 * Headings font-family: "Linux Libertine", Georgia, Times, serif;
 * Body copy font-family: Arimo, "Liberation Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;

Reduced type size for navigational elements: Type size for navigation elements in the sidebar are reduced by 0.1–0.3 em to help them fade to the background in comparison to the page content which is the foreground. Since the navigation areas are distinct, we expect that changes in the size will not hamper clicking on the links.

Implementation
The specific CSS changes are in Extension:VectorBeta in (written in the dynamic stylesheet language Requests for comment/LESS).

If you are interested in further technical information on the rationale behind this experiment, you can read more at Wikimedia Foundation Design/Typography.