Unity'de zıplama kodu yere inmek yerine havada duruyor

using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;

[RequireComponent(typeof(CharacterController))]

public class PlayerMovement : MonoBehaviour.
{
 Rigidbody rb;
 CharacterController controller;

 public float speed;
 public float gravity;
 public float jumpHeight;
 public float minJump;

 public Transform groundCheck;
 public float groundDistance = 0.4f;
 public LayerMask groundMask;

 public float originalHeight;
 public float crouchHeight;

 Vector3 velocity;
 bool isGrounded;

 private void Awake()
 {
 controller = GetComponent<CharacterController>();
 }

 private void Start()
 {
 Cursor.lockState = CursorLockMode.Locked;
 Cursor.visible = true;
 }

 void Update()
 {

 if (isGrounded && velocity.y < 0)
 {
 velocity.y = -2f;
 }

 float x = Input.GetAxis("Horizontal");
 float z = Input.GetAxis("Vertical");

 Vector3 move = transform.right * x + transform.forward * z;

 controller.Move(speed * Time.deltaTime * move);

 #region Crouch.
 if (Input.GetKeyDown(KeyCode.LeftControl))
 {
 controller.height = crouchHeight;

 }

 if(Input.GetKeyUp(KeyCode.LeftControl))
 controller.height = originalHeight;

 #endregion

 #region Gravity.
 isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);
 if(isGrounded && velocity.y < 0)
 {
 velocity.y = 0f;
 }
 velocity.y += gravity * Time.deltaTime;
 controller.Move(velocity * Time.deltaTime);
 #endregion

 #region Jump.

 //Z�plama
 if (Input.GetButtonDown("Jump") && isGrounded)
 {
 velocity.y = Mathf.Sqrt(jumpHeight * -5f * gravity);
 }

 #endregion
 }

}