tweak: more priminent invalid form color

Change-Id: Ia3265f5934df0715813f69bcb6147f6dbf3e008b
Reviewed-on: http://gerrit.tine20.com/customers/14467
Reviewed-by: Cornelius Weiss <c.weiss@metaways.de>
Tested-by: Cornelius Weiss <c.weiss@metaways.de>

tine20/Tinebase/css/Tinebase.css

@@ -974,7 +974,7 @@ textarea.x-form-field.tinebase-editmultipledialog-noneedit {
 
 textarea.x-form-invalid,
 .x-form-invalid {
-    background-color: #fee;
+    background-color: #fdd;
     border-bottom: 1px solid #ff7870 !important;
 }