button.css

/*!
 * jQuery UI Button 1.13.3
 * https://jqueryui.com
 *
 * Copyright OpenJS Foundation and other contributors
 * Released under the MIT license.
 * https://jquery.org/license
 *
 * https://api.jqueryui.com/button/#theming
 */
.ui-button {
	padding: .4em 1em;
	display: inline-block;
	position: relative;
	line-height: normal;
	margin-right: .1em;
	cursor: pointer;
	vertical-align: middle;
	text-align: center;
	-webkit-user-select: none;
	-moz-user-select: none;
	-ms-user-select: none;
	user-select: none;

	/* Support: IE <= 11 */
	overflow: visible;
}

.ui-button,
.ui-button:link,
.ui-button:visited,
.ui-button:hover,
.ui-button:active {
	text-decoration: none;
}

/* to make room for the icon, a width needs to be set here */
.ui-button-icon-only {
	width: 2em;
	box-sizing: border-box;
	text-indent: -9999px;
	white-space: nowrap;
}

/* no icon support for input elements */
input.ui-button.ui-button-icon-only {
	text-indent: 0;
}

/* button icon element(s) */
.ui-button-icon-only .ui-icon {
	position: absolute;
	top: 50%;
	left: 50%;
	margin-top: -8px;
	margin-left: -8px;
}

.ui-button.ui-icon-notext .ui-icon {
	padding: 0;
	width: 2.1em;
	height: 2.1em;
	text-indent: -9999px;
	white-space: nowrap;

}

input.ui-button.ui-icon-notext .ui-icon {
	width: auto;
	height: auto;
	text-indent: 0;
	white-space: normal;
	padding: .4em 1em;
}

/* workarounds */
/* Support: Firefox 5 - 40 */
input.ui-button::-moz-focus-inner,
button.ui-button::-moz-focus-inner {
	border: 0;
	padding: 0;
}

File

core/assets/vendor/jquery.ui/themes/base/button.css

/*!
 * jQuery UI Button 1.13.3
 * https://jqueryui.com
 *
 * Copyright OpenJS Foundation and other contributors
 * Released under the MIT license.
 * https://jquery.org/license
 *
 * https://api.jqueryui.com/button/#theming
 */
.ui-button {
	padding: .4em 1em;
	display: inline-block;
	position: relative;
	line-height: normal;
	margin-right: .1em;
	cursor: pointer;
	vertical-align: middle;
	text-align: center;
	-webkit-user-select: none;
	-moz-user-select: none;
	-ms-user-select: none;
	user-select: none;

	/* Support: IE <= 11 */
	overflow: visible;
}

.ui-button,
.ui-button:link,
.ui-button:visited,
.ui-button:hover,
.ui-button:active {
	text-decoration: none;
}

/* to make room for the icon, a width needs to be set here */
.ui-button-icon-only {
	width: 2em;
	box-sizing: border-box;
	text-indent: -9999px;
	white-space: nowrap;
}

/* no icon support for input elements */
input.ui-button.ui-button-icon-only {
	text-indent: 0;
}

/* button icon element(s) */
.ui-button-icon-only .ui-icon {
	position: absolute;
	top: 50%;
	left: 50%;
	margin-top: -8px;
	margin-left: -8px;
}

.ui-button.ui-icon-notext .ui-icon {
	padding: 0;
	width: 2.1em;
	height: 2.1em;
	text-indent: -9999px;
	white-space: nowrap;

}

input.ui-button.ui-icon-notext .ui-icon {
	width: auto;
	height: auto;
	text-indent: 0;
	white-space: normal;
	padding: .4em 1em;
}

/* workarounds */
/* Support: Firefox 5 - 40 */
input.ui-button::-moz-focus-inner,
button.ui-button::-moz-focus-inner {
	border: 0;
	padding: 0;
}