qt: change QLineEdit error background

Author: w0xlt

src/qt/guiconstants.h

@@ -25,7 +25,7 @@ static const int STATUSBAR_ICONSIZE = 16;
 static const bool DEFAULT_SPLASHSCREEN = true;
 
 /* Invalid field background style */
-#define STYLE_INVALID "background:#FF8080"
+#define STYLE_INVALID "border: 3px solid #FF8080"
 
 /* Transaction list -- unconfirmed transaction */
 #define COLOR_UNCONFIRMED QColor(128, 128, 128)