RGB and photoresistor- purple light turns off when light on

/*
*Divya Inaganti
*June 14, 2017
*RGB and photoresistor activity
*/
const int photoPin = A0;
const int PinRed= 9;
const int PinGreen=10;
const int PinBlue= 11;
int photoValue= 0;
int lightVal= 0;
const int pinButton = 4;
void setup()
{
  Serial.begin (9600);
 pinMode(photoPin, INPUT);
  pinMode (PinRed, OUTPUT);
  pinMode (PinGreen, OUTPUT);
  pinMode (PinBlue, OUTPUT);
  pinMode(pinButton, INPUT);


analogWrite(PinRed, 255);
analogWrite(PinGreen, 0);
analogWrite(PinBlue,0);
delay(200);
analogWrite(PinRed, 0);
analogWrite(PinGreen, 255);
analogWrite(PinBlue,0);
delay(200);
analogWrite(PinRed, 0);
analogWrite(PinGreen, 0);
analogWrite(PinBlue,255);
delay(200);
analogWrite(PinRed, 0);
analogWrite(PinGreen, 0);
analogWrite(PinBlue,0);
 }
void loop()
{
photoValue= analogRead (photoPin);
  lightVal= map(photoValue, 0, 730, 255, 0);
  lightVal= constrain(lightVal, 0, 255);
  Serial.print ("Photoresistor value = ");
  Serial.print(photoValue);
  Serial.print ("lightVal = ");
  Serial.println(lightVal);
  analogWrite(PinRed, lightVal);
  analogWrite(PinBlue, lightVal);
  analogWrite(PinGreen,0);
  delay(100);