refactor(external): consolidate global CSS overrides into ExternalApp component

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

src/ExternalApp.vue

@@ -18,23 +18,37 @@ defineOptions({ name: 'LibreSignExternal' })
 import RightSidebar from './components/RightSidebar/RightSidebar.vue'
 </script>
 
+<style lang="scss">
+// Override server.css layout rules that assume authenticated header layout.
+// `html body #content` beats the specificity of server.css selectors.
+html body #content {
+	position: fixed;
+	inset: 0;
+	margin: 0;
+	width: 100vw;
+	height: 100vh;
+	border-radius: 0;
+}
+
+// On mobile, NcAppSidebar relies on NcContent to overlay content.
+// Without it, force the sidebar to cover the viewport as a full-screen overlay.
+@media (max-width: 512px) {
+	#app-sidebar {
+		position: fixed;
+		inset: 0;
+		width: 100vw !important;
+		max-width: 100vw !important;
+		height: 100vh;
+		z-index: 2000;
+	}
+}
+</style>
+
 <style lang="scss" scoped>
 .external-app {
 	position: absolute;
 	inset: 0;
 	display: flex;
 	background-color: var(--color-main-background);
-	// On mobile, NcAppSidebar relies on NcContent to overlay content.
-	// Without it, force the sidebar to cover the viewport as a full-screen overlay.
-	@media (max-width: 512px) {
-		:deep(#app-sidebar) {
-			position: fixed;
-			inset: 0;
-			width: 100vw !important;
-			max-width: 100vw !important;
-			height: 100vh;
-			z-index: 2000;
-		}
-	}
 }
 </style>