Refactor code structure for improved readability and maintainability

Fuchs/js/intranet/modules/fis.inv_shared.scss

@@ -399,6 +399,33 @@
 	}
 }
 
+/* Backend-authoritative draft editing (ADR 0006): server-side plausibility findings
+   rendered above the editor, and the change-history dialog table. */
+.edit_frm .invoice_layout .dvalidation {
+	margin: 0 0 1rem 0;
+
+	&.hidden { display: none; }
+
+	.dvmsg {
+		padding: 0.4rem 0.7rem;
+		margin: 0.25rem 0;
+		border-radius: 0.2rem;
+		font-size: 0.9rem;
+		border-left: 4px solid #999;
+		background: #f5f5f5;
+
+		&.error   { border-left-color: #c0392b; background: #fdecea; color: #922; }
+		&.warning { border-left-color: #e0a800; background: #fff8e1; color: #7a5c00; }
+		&.info    { border-left-color: #3498db; background: #eaf4fb; color: #1c5a82; }
+	}
+}
+
+.dhist {
+	.invtbl { width: 100%; }
+	td, th { padding: 0.3rem 0.6rem; text-align: left; vertical-align: top; }
+	tbody tr:nth-child(even) { background: #fafafa; }
+}
+
 .modal-body .lstfrm {
 	display: block;
 	position: relative;