int led1 = 11, led2 = 10;
byte br1 = 0, br2 = 0;

void setup() {
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  Serial.begin(9600);
  Serial.println("Q/A: terang, W/S: redup");
}

void loop() {
  analogWrite(led1, br1);
  analogWrite(led2, br2);

  if (Serial.available()) {
    char c = Serial.read();
    br1 += (c == 'Q' || c == 'q') ? 10 : (c == 'W' || c == 'w') ? -10 : 0;
    br2 += (c == 'A' || c == 'a') ? 10 : (c == 'S' || c == 's') ? -10 : 0;
    br1 = constrain(br1, 0, 255);
    br2 = constrain(br2, 0, 255);
    Serial.print("LED 1: "); Serial.println(br1);
    Serial.print("LED 2: "); Serial.println(br2);
  }
}