<pclass="lead">Bootstrap follows common web standards and—with minimal extra effort—can be used to create sites that are accessible to those using <abbrtitle="Assistive Technology"class="initialism">AT</abbr>.</p>
<p>If your navigation contains many links and comes before the main content in the DOM, add a <code>Skip to main content</code> link before the navigation <ahref="http://a11yproject.com/posts/skip-nav-links/">(read why)</a>. Using the <code>.sr-only</code> class will visually hide the skip link, and the <code>.sr-only-focusable</code> class will ensure that the link becomes visible once focused (for sighted keyboard users).</p>
<p>When nesting headings (<code><h1></code> - <code><h6></code>), your primary document header should be an <code><h1></code>. Subsequent headings should make logical use of <code><h2></code> - <code><h6></code> such that screen readers can construct a table of contents for your pages.</p>
<p>Learn more at <ahref="http://squizlabs.github.io/HTML_CodeSniffer/Standards/Section508/">HTML CodeSniffer</a> and <ahref="http://accessibility.psu.edu/headings">Penn State's AccessAbility</a>.</p>
<p>Currently, some of the default color combinations available in Bootstrap (such as the various <ahref="../css/#buttons">styled button</a> classes, some of the code highlighting colors used for <ahref="../css/#code-block">basic code blocks</a>, the <code>.bg-primary</code><ahref="../css/#helper-classes-backgrounds">contextual background</a> helper class, and the default link color when used on a white background) have a low contrast ratio (below the <ahref="http://www.w3.org/TR/WCAG20/#visual-audio-contrast-contrast">recommended ratio of 4.5:1</a>). This can cause problems to users with low vision or who are color blind. These default colors may need to be modified to increase their contrast and legibility.</p>
