Help Improve movement script

Hi guys there is anyway to improve this code? when the player move down on a surface that have a slope it doesn't touch the ground and make "little jump" that is unrealistic and kind of annoying.

I gonna quote the whole code I have, if you have any suggestion is welcomed.

 /// <summary> 
 /// Charactercontrollercs.cs 
 /// Character Controller in CSharp v2.3 
 /// </summary> 
 using UnityEngine; 
 
 public class CharacterControllercs : MonoBehaviour { 
              
     //Var definition 
     public bool swimming = false;                    //Can be triggert to slow down the movements (like when u swim) 
     public string moveStatus = "idle";                //movestatus for animations 
      
     //Movement speeds 
     private float jumpSpeed = 8.0f;                    //Jumpspeed / Jumpheight 
     private float gravity = 20.0f;                    //Gravity for jump 
     private float runSpeed = 10.0f;                    //Speed when the Character is running 
     private float walkSpeed = 4.0f;                    //Speed when the Character is walking (normal movement) 
     private float rotateSpeed = 250.0f;                //Rotationspeed of the Character 
     private float walkBackMod = 0.75f;                //Speed in Percent for walk backwards and sidewalk 
      
     //Internal vars to work with 
     private float speedMod = 0.0f;                    //temp Var for Speedcalculation 
     private bool grounded = false;                    //temp var if the character is grounded 
     private Vector3 moveDirection = Vector3.zero;    //move direction of the Character 
     private bool isWalking = false;                    //toggle var between move and run 
     private bool jumping = false;                    //temp var for jumping 
     private bool mouseSideButton = false;            //temp var for mouse side buttons 
     private float pbuffer = 0.0f;                    //Cooldownpuffer for SideButtons 
     private float coolDown = 0.5f;                   //Cooldowntime for SideButtons 
     private CharacterController controller;            //CharacterController for movement 
      
     //Every Frame 
     void Update () 
     { 
         //Set idel animation 
         moveStatus = "idle"; 
         isWalking = true; 
              
         // Hold "Run" to run 
         if(Input.GetAxis("Run") != 0) 
             isWalking = false; 
          
         // Only allow movement and jumps while grounded 
         if(grounded) { 
              
             //movedirection 
             moveDirection = new Vector3((Input.GetMouseButton(1) ? Input.GetAxis("Horizontal") : 0),0,Input.GetAxis("Vertical")); 
              
             //pushbuffer to avoid on/off flipping 
             if(pbuffer>0) 
                 pbuffer -=Time.deltaTime; 
             if(pbuffer<0)pbuffer=0; 
                             
             //Automove Sidebuttonmovement 
             if((Input.GetAxis("Toggle Move") !=0) && pbuffer == 0){ 
                 pbuffer=coolDown; 
                 mouseSideButton = !mouseSideButton; 
             } 
             if(mouseSideButton && ((Input.GetAxis("Vertical") != 0) || Input.GetButton("Jump")) || (Input.GetMouseButton(0) && Input.GetMouseButton(1)))
                 mouseSideButton = false;             
              
             //L+R MouseButton Movement 
             if (Input.GetMouseButton(0) && Input.GetMouseButton(1) || mouseSideButton) 
                 moveDirection.z += 1; 
             if (moveDirection.z > 1)
                 moveDirection.z = 1;
                  
             //Strafing move (like Q/E movement     
             moveDirection.x -= Input.GetAxis("Strafing"); 
                  
               // if moving forward and to the side at the same time, compensate for distance 
               if(Input.GetMouseButton(1) && (Input.GetAxis("Horizontal") != 0) && (Input.GetAxis("Vertical") != 0)) { 
                 moveDirection *= 0.7f; 
               } 
                                
             //Speedmodification / is moving forward or side/backward 
             speedMod = ((Input.GetAxis("Vertical") < 0) || (Input.GetMouseButton(1) && (Input.GetAxis("Horizontal")) != 0) || Input.GetAxis("Strafing") != 0) ? walkBackMod : 1.0f;
              
             //Use run or walkspeed 
             moveDirection *= isWalking ? walkSpeed * speedMod : runSpeed * speedMod; 
              
             //reduce movement by 70% when swimming is toggled    
             moveDirection*= swimming ? 0.7f : 1; 
                        
             // Jump! 
             if(Input.GetButton("Jump")){ 
                 jumping = true; 
                 moveDirection.y = jumpSpeed; 
             } 
              
             //movestatus normal movement (for animations)               
             if((moveDirection.x == 0 ) && (moveDirection.z == 0)) 
                 moveStatus = "idle";             
             if(moveDirection.z > 0) 
                 moveStatus = isWalking ? "walking" : "running"; 
             if(moveDirection.z < 0) 
                 moveStatus = isWalking ? "backwalking" : "backrunning";         
             if(moveDirection.x > 0) 
                 moveStatus = isWalking ? "sidewalking_r" : "siderunning_r"; 
             if(moveDirection.x < 0) 
                 moveStatus = isWalking ? "sidewalking_l" : "siderunning_l";     
              
             //movestatus swim movement (for animations)               
             if(swimming){ 
                 if((moveDirection.x == 0 ) && (moveDirection.z == 0)) 
                     moveStatus = "swimidle";             
                 if(moveDirection.z > 0) 
                     moveStatus = isWalking ? "swim" : "swimfast"; 
                 if(moveDirection.z < 0) 
                     moveStatus = isWalking ? "backswim" : "backswimfast";         
                 if(moveDirection.x > 0) 
                     moveStatus = isWalking ? "sideswim_r" : "sideswimfast_r"; 
                 if(moveDirection.x < 0) 
                     moveStatus = isWalking ? "sidewswim_l" : "sideswimfast_l";     
                 if(jumping) 
                     moveStatus = "swimup";                     
             }   
              
             //transform direction 
             moveDirection = transform.TransformDirection(moveDirection);         
          
         } 
         // Allow turning at anytime. Keep the character facing in the same direction as the Camera if the right mouse button is down. 
         if(Input.GetMouseButton(1)) { 
             transform.rotation = Quaternion.Euler(0,Camera.main.transform.eulerAngles.y,0); 
         } else { 
             transform.Rotate(0,Input.GetAxis("Horizontal") * rotateSpeed * Time.deltaTime, 0); 
         } 
          
         //Apply gravity 
         moveDirection.y -= gravity * Time.deltaTime; 
          
         //Get CharacterController 
         controller = GetComponent<CharacterController>(); 
         //Move Charactercontroller and check if grounded 
         grounded = ((controller.Move(moveDirection * Time.deltaTime)) & CollisionFlags.Below) != 0; 
          
         //Reset jumping after landing 
         jumping = grounded ? false : jumping; 
          
         //movestatus jump/swimup (for animations)       
         if(jumping) 
             moveStatus = "jump"; 
         if(jumping && swimming) 
             moveStatus = "swimup";     
     } 
 }  

Is not my code I took from FCC. It work exactly how I wonted. But i can't make it work better with the ground. I'm workin on animation, but I'm not going to attach that part of the code.