How to Limit Z Axis on my FirstPersonCamera?

I’ve found other answers, but they are simply not working with my code. I’m a beginner, so I’m probably just not doing it right. Here is my code:

using UnityEngine;
using System.Collections;
public class FirstPersonCamera : MonoBehaviour {

public bool lockCursor;
public float mouseSensitivity = 10;
public Vector2 pitchMinMax = new Vector2 (-27, 50);
public float rotationSmoothTime = .12f;
Vector3 rotationSmoothVelocity;
Vector3 currentRotation;
float yaw;
float pitch;

void Start() {
	if (lockCursor) {
		Cursor.lockState = CursorLockMode.Locked;
		Cursor.visible = false;

void LateUpdate () {

	yaw += Input.GetAxis ("Mouse X") * mouseSensitivity;
	pitch -= Input.GetAxis ("Mouse Y") * mouseSensitivity;
	pitch = Mathf.Clamp (pitch, pitchMinMax.x, pitchMinMax.y);
	currentRotation = Vector3.SmoothDamp (currentRotation, new Vector3 (pitch, yaw), ref rotationSmoothVelocity, rotationSmoothTime);
	transform.eulerAngles = currentRotation;


Plese be more specific about your question.
What you mean by Limiting your Z axis?
It’s the Z rotation, Z position?