Remove unused CSS styles

* could not find an traces of .popup and .arrow anywhere else

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

core/css/styles.scss

@@ -1107,64 +1107,6 @@ span.ui-icon {
 	}
 }
 
-/* ---- APP SETTINGS - LEGACY, DO NOT USE THE POPUP! ---- */
-
-.popup {
-	background-color: $color-main-background;
-	border-radius: 3px;
-	box-shadow: 0 0 10px $color-box-shadow;
-	color: nc-lighten($color-main-text, 20%);
-	padding: 10px;
-	position: fixed !important;
-	z-index: 100;
-	&.topright {
-		top: 7em;
-		right: 1em;
-	}
-	&.bottomleft {
-		bottom: 1em;
-		left: 33em;
-	}
-	.close {
-		position: absolute;
-		top: 0.2em;
-		right: 0.2em;
-		height: 20px;
-		width: 20px;
-		background: url('../img/actions/close.svg?v=1') no-repeat center;
-	}
-	h2 {
-		font-size: 20px;
-	}
-}
-
-.arrow {
-	border-bottom: 10px solid white;
-	border-left: 10px solid transparent;
-	border-right: 10px solid transparent;
-	display: block;
-	height: 0;
-	position: absolute;
-	width: 0;
-	z-index: 201;
-	&.left {
-		left: -13px;
-		bottom: 1.2em;
-		-webkit-transform: rotate(270deg);
-		-ms-transform: rotate(270deg);
-		transform: rotate(270deg);
-	}
-	&.up {
-		top: -8px;
-		right: 6px;
-	}
-	&.down {
-		-webkit-transform: rotate(180deg);
-		-ms-transform: rotate(180deg);
-		transform: rotate(180deg);
-	}
-}
-
 /* ---- BREADCRUMB ---- */
 
 div.crumb {