character rotation to mouse on x axis

hey guys. i got this script for my character to follow the mouse to the left and to the right.

public float turnSpeed = 15;
Camera mainCamera;
// Start is called before the first frame update
void Start()
{
    mainCamera = Camera.main;
    Cursor.visible = false;
    Cursor.lockState = CursorLockMode.Locked;

}

// Update is called once per frame
void FixedUpdate()
{
    float yawCamera = mainCamera.transform.rotation.eulerAngles.y;
   

    transform.rotation = Quaternion.Slerp(transform.rotation, Quaternion.Euler(-90f, yawCamera+180f, -65f), turnSpeed * Time.fixedDeltaTime);
}

}

if i try the same for up and down it doesnt work. i just have to rotate the x axis of the obect.anywone can help me?

i fixed it by myself. Pretty easy afterwards XD.
Had to negate the x Axis ,but now my Character follows my Mouse to every Direction. (3. person rotation Controller).

public float turnSpeed = 15;
Camera mainCamera;

void Start()
{
    mainCamera = Camera.main;
    

}


void FixedUpdate()
{
    float yCamera = mainCamera.transform.rotation.eulerAngles.y;
    float xCamera = mainCamera.transform.rotation.eulerAngles.x;

    transform.rotation = Quaternion.Slerp(transform.rotation, Quaternion.Euler(-xCamera-,yawCamera , 0f), turnSpeed * Time.fixedDeltaTime);
}

}