Implement USER_DEFINED ReadMode color

src/main/java/com/kdanmobile/reader/ReaderViewModel.kt

@@ -578,7 +578,10 @@ class ReaderViewModel(private val pdfSdkLicense: String, private val pdfSdkRsaMs
     }
 
     private fun updateReadMode() {
-        kmpdfDocumentController?.readMode = readMode.mode
+        when (readMode) {
+            ReadMode.READ_MODE_DAY, ReadMode.READ_MODE_NIGHT, ReadMode.READ_MODE_SOFT -> kmpdfDocumentController?.readMode = readMode.mode
+            ReadMode.USER_DEFINED -> kmpdfDocumentController?.setReadMode(232, 232, 232)
+        }
         kmpdfDocumentController?.refresh(false)
         kmpdfFactory?.readerView?.context?.also {
             val colorResId = when (readMode) {