fix: use semantic color for prayer section backgrounds in light mode

Replace var(--accent-dark) with var(--color-bg-secondary) which maps
to the correct color in both modes, removing dead @media overrides
that referenced the undefined var(--accent-light). Also match rosary
cross fill to Benedictus medal color in light mode.

src/routes/[faithLang=faithLang]/[prayers=prayersLang]/[prayer]/+page.svelte

@@ -102,7 +102,7 @@ h1 {
 }
 .gebet-wrapper {
 	padding: 1.5em;
-	background-color: var(--accent-dark);
+	background-color: var(--color-bg-secondary);
 	box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
 }
 .intro {
@@ -110,14 +110,6 @@ h1 {
 	font-style: italic;
 	text-align: center;
 }
-@media(prefers-color-scheme: light) {
-	.gebet-wrapper {
-		background-color: var(--accent-light);
-	}
-	:global(.gebet v:lang(la)) {
-		color: black;
-	}
-}
 </style>
 
 <div class="container">