Typography refresh/ja

目標
文字はウィキペディアの言語における中核的な視覚要素です. この（オプトインの）文字体裁に関する更新は次の需要にもとづいています.

可読性：書体はあらゆるサイズで判別しやすく読み取りやすくなっていなければなりません. 要素としての文字は、記事内容とインターフェイスとを区別する助けなければなりません.

アクセシビリティ：失読症と視覚障害が情報アクセスの障害になってはなりません. 障害のある利用者にもアクセスを可能にしなければなりません.

Availability: 私たちが用いるすべての書体は、すでに利用できる、または利用可能なものである必要があります. どんな書体を選ぶにしても、デバイスやプラットフォーム (OS X, Windows, Linux, Mobile Platforms)を通じて、優雅にdegradeしなければいけません.

一貫性：デスクトップでも携帯機器でも変わらない視覚体験.

Key Changes
TLDR: 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.

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見出しのfont-family: Georgia, 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.

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本文のfont-family: "Helvetica Neue", "Helvetica", "Nimbus Sans L", "Arial", "Liberation Sans", sans-serif; While Georgia and Helvetica are fonts optimized for the web, we can see that body gracefully degrades to Arial because it is freely available on nearly every computer and operating system while being a screen-friendly typeface. After that, there is a free font, Liberation Sans, and finally a fallback that is always available, sans-serif. This selection may change as other typefaces develop ubiquity. For the near future, Arial will continue to serve as WMF's fallback. On Linux-based operating systems, Nimbus Sans L & Liberation Sans will be specified as the sans-serif fonts. Note that free systems may also substitute other free fonts for proprietary ones mentioned earlier in the stack.

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ナビゲーション要素での文字サイズ縮小 : 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 article which is the foreground. Since the navigation areas are distinct, we expect that changes in the size will not hamper clicking on the links.

実装
この実験の背景にある理由（rationale）についての詳しい技術情報については、こちらをご覧ください.