Outline style override. (#3872)

quadrat/assets/theme.css

@@ -41,6 +41,11 @@
 	text-align: right;
 }
 
+.wp-block-button.is-style-outline.wp-block-button__link,
+.wp-block-button.is-style-outline .wp-block-button__link {
+	border: 2px solid currentColor;
+}
+
 .wp-block-button.is-style-outline.wp-block-button__link:not(.has-background):not(.has-text-color):hover, .wp-block-button.is-style-outline.wp-block-button__link:not(.has-background):not(.has-text-color):focus, .wp-block-button.is-style-outline.wp-block-button__link:not(.has-background):not(.has-text-color).has-focus,
 .wp-block-button.is-style-outline .wp-block-button__link:not(.has-background):not(.has-text-color):hover,
 .wp-block-button.is-style-outline .wp-block-button__link:not(.has-background):not(.has-text-color):focus,

quadrat/sass/blocks/_buttons.scss

@@ -1,6 +1,7 @@
 .wp-block-button.is-style-outline {
 	&.wp-block-button__link,
 	.wp-block-button__link {
+		border: 2px solid currentColor; // The priority of global styles in the post editor overrides the outline style variation, so this line is needed.
 		&:not(.has-background):not(.has-text-color) {
 			&:hover,
 			&:focus,