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Buttons are used for actions, like in forms, while textual hyperlinks are used for destinations, or moving from one page to another.

Default button

Use the standard—yet classy—.btn for form actions and primary page actions. These are used extensively around the site.

When using a <button> element, always specify a type. When using a <a> element, always add role="button" for accessibility.

You can find them in two sizes: the default .btn and the smaller .btn-sm.

Primary button

Primary buttons are green and are used to indicate the primary action on a page. When you need your buttons to stand out, use .btn.btn-primary. You can use it with both button sizes—just add .btn-primary.

Danger button

Danger buttons are red. They help reiterate that the intended action is important or potentially dangerous (e.g., deleting a repo or transferring ownership). Similar to the primary buttons, just add .btn-danger.

Outline button

Outline buttons downplay an action as they appear like boxy links. Just add .btn-outline and go.

Large button

Use .btn-large to increase the padding and border radius of a button. This is useful for prominent calls to action in hero sections.

Type scale utilities can be used to alter the font-size if needed. Padding is applied in em's so that it scales proportionally with the font-size.

Use .btn-large with a type scale utility to transform the text to a bigger size.

Disabled state

Disable <button> and <a> elements with the aria-disabled="true" attribute.

Similar styles are applied to primary, danger, and outline buttons:

Block button

Make any button full-width by adding .btn-block. It adds width: 100%;, changes the display from inline-block to block, and centers the button text.

Create a button that looks like a link with .btn-link. Rather than using an <a> to trigger JS, this style on a <button> should be used for better accessibility.

The .btn-link class is not designed to be used with .btn; the overlapping styles are not compatible.

Invisible button

When you want a link, but you want it padded and line heighted like a button best for "cancel" actions on forms.

Octicon button

Icon-only buttons that turn blue on hover. Use .btn-octicon-danger to turn an icon red on hover.

Close button

When using the octicon-x icon for a close button, add .close-button to remove the default button styles.

Button with icons

Icons can be added to any button.

Button with counts

You can easily append a count to a small button. Add the .with-count class to the .btn-sm and then add the .social-count after the button.

Be sure to clear the float added by the additional class.

You can also use the counter component within buttons:

Button groups

Have a hankering for a series of buttons that are attached to one another? Wrap them in a .BtnGroup and the buttons will be rounded and spaced automatically.

Add .BtnGroup-parent to parent elements, like <form>s or <details>s, within .BtnGroups for proper spacing and rounded corners.

Hidden text button

Use .hidden-text-expander to indicate and toggle hidden text.

You can also make the expander appear inline by adding .inline.