[TASK] Optimize backend page header info text/collapsible

Related: T3DEMO-269

src/extensions/site_t3demo/Resources/Private/Backend/Templates/PageLayout/Header.html

@@ -6,16 +6,17 @@
 
 <div class="b_notes">
 	<input type="checkbox" id="notes_detail" class="b_pseudo" />
-	<label class="b_notes__header-label" for="notes_detail">
-		<h3 class="b_notes__header">{data.infotext_header}</h3>
-		<f:if condition="{data.infotext}">
-			<span class="b_notes__indicator b_notes__indicator--expand">
-				<core:icon identifier="actions-view-list-expand" size="default"/>
-			</span>
-			<span class="b_notes__indicator b_notes__indicator--collapse">
-				<core:icon identifier="actions-view-list-collapse" size="default"/>
-			</span>
-		</f:if>
+	<label class="b_notes__header-label {f:if(condition: data.infotext, then: 'b_notes__header-label--expandable')}" for="notes_detail">
+		<h3 class="b_notes__header">
+			<f:if condition="{data.infotext}">
+				<span class="b_notes__indicator b_notes__indicator--expand">
+					<core:icon identifier="actions-add" size="small"/>
+				</span>
+				<span class="b_notes__indicator b_notes__indicator--collapse">
+					<core:icon identifier="actions-remove" size="small"/>
+				</span>
+			</f:if>
+			{data.infotext_header}</h3>
 	</label>
 	<f:if condition="{data.infotext}">
 		<div class="b_notes__detailcontainer">

src/extensions/site_t3demo/Resources/Private/Scss/t3skin_override.scss

@@ -128,19 +128,24 @@
 	}
 
 	&__header-label {
-		cursor: pointer;
 		position: relative;
 		width: 100%;
+
+		&--expandable {
+			cursor: pointer;
+		}
 	}
 
 	&__indicator {
-		position: absolute;
-		right: 0;
-		top: 2px;
+		position: relative;
+		bottom: 2px;
+		.icon-size-small {
+
+		}
 		&--collapse {
 			display: none;
 			#notes_detail:checked ~ .b_notes__header-label & {
-				display: block;
+				display: inline;
 			}
 		}
 		#notes_detail:checked ~ .b_notes__header-label &--expand {