fix(styles): Adjust background stylings

Signed-off-by: Ferdinand Thiessen <[email protected]>

Author: susnux

core/css/apps.scss

@@ -29,15 +29,15 @@ html {
 	width: 100%;
 	height: 100%;
 	position: absolute;
-	// color-background-plain should always be defined. It is the primary user colour
+	// color-background-plain should always be defined.
 	background-color: var(--color-background-plain, var(--color-main-background));
 }
 
 body {
-	// color-background-plain should always be defined. It is the primary user colour
+	// color-background-plain should always be defined.
 	background-color: var(--color-background-plain, var(--color-main-background));
-	// user background, or plain colour and finally default admin background
-	background-image: var(--image-background, var(--image-background-plain, var(--image-background-default)));
+	// user background, or plain color
+	background-image: var(--image-background);
 	background-size: cover;
 	background-position: center;
 	position: fixed;

core/css/guest.scss

@@ -25,17 +25,14 @@ body {
 	font-size: .875em;
 	line-height: 1.6em;
 	font-family: system-ui, -apple-system, "Segoe UI", Roboto, Oxygen-Sans, Cantarell, Ubuntu, "Helvetica Neue", "Noto Sans", "Liberation Sans", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
-	color: var(--color-text);
+	color: var(--color-background-plain-text, #ffffff);
 	text-align: center;
-	/* As guest, there is no color-background-plain */
-	background-color: var(--color-background-plain, var(--color-primary-element-default, #0082c9));
-	/* As guest, there is no user background (--image-background)
-	1. User background if logged in ('no' if removed, that way the variable is _defined_)
-	2. Empty background if enabled ('yes' is used, that way the variable is _defined_)
-	3. Else default background
-	4. Finally default gradient (should not happened, the background is always defined anyway) */
-	background-image: var(--image-background, var(--image-background-plain, var(--image-background-default, linear-gradient(40deg, #0082c9 0%, #30b6ff 100%))));
-    background-attachment: fixed;
+	background-color: var(--color-background-plain, #0082c9);
+	/* 
+	User background if logged in ('no' if removed, that way the variable is _defined_)
+	Fallback to default gradient (should not happened, the background is always defined anyway) */
+	background-image: var(--image-background, linear-gradient(40deg, #0082c9 0%, #30b6ff 100%));
+	background-attachment: fixed;
 	min-height: 100%; /* fix sticky footer */
 	height: auto;
 	overflow: auto;

core/css/header.scss

@@ -162,7 +162,7 @@
 
 	/* Right header standard */
 	.header-right {
-		> .header-menu img {
+		> .header-menu__trigger img {
 			filter: var(--background-image-invert-if-bright);
 		}
 		> div,