Add highcontrast style for dark mode

Signed-off-by: Janis Köhr <janis.koehr@novatec-gmbh.de>

apps/accessibility/css/highcontrastdark.scss

@@ -0,0 +1,25 @@
+// SCSS variables
+$color-main-text: #fff;
+$color-main-background: #000;
+
+$color-background-dark: lighten($color-main-background, 30%);
+$color-background-darker: lighten($color-main-background, 30%);
+
+$color-text-maxcontrast: $color-main-text;
+$color-text-light: $color-main-text;
+$color-text-lighter: $color-main-text;
+
+$color-loading-light: #000;
+$color-loading-dark: #ddd;
+
+$color-box-shadow: $color-main-text;
+
+$color-border: lighten($color-main-background, 50%);
+$color-border-dark: lighten($color-main-background, 50%);
+
+[class^='icon-'], [class*=' icon-'],
+.action,
+#appmenu li a,
+.menutoggle {
+	opacity: 1 !important;
+}

apps/accessibility/lib/Controller/AccessibilityController.php

@@ -132,6 +132,9 @@ class AccessibilityController extends Controller {
 
 		foreach ($userValues as $key => $scssFile) {
 			if ($scssFile !== false) {
+				if ($scssFile === 'highcontrast' && in_array('dark', $userValues)) {
+					$scssFile .= 'dark';
+				}
 				$imports .= '@import "' . $scssFile . '";';
 			}
 		}