Dark theme fixes for vue-at

Signed-off-by: Joas Schilling <coding@schilljs.com>

css/icons.scss

@@ -76,4 +76,14 @@
 	.icon-group-forced-white {
 		background-image: url(icon-color-path('group', 'actions', 'fff', 1, true));
 	}
+
+	.atwho-view {
+		background: var(--color-main-background);
+		color: var(--color-main-text);
+	}
+
+	.atwho-cur {
+		background: var(--color-primary);
+		color: var(--color-primary-text);
+	}
 }

src/components/NewMessageForm/AdvancedInput/AdvancedInput.vue

@@ -305,10 +305,10 @@ export default {
 	margin: 0;
 }
 
-//Support for the placehoder text in the div contenteditable
+// Support for the placeholder text in the div contenteditable
 [contenteditable]:empty:before{
 	content: attr(placeholder);
 	display: block;
-	color: gray;
+	color: var(--color-text-maxcontrast);
 }
 </style>