Change Color At Level Up

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class LevelSystem : MonoBehaviour {

    [SerializeField] int[] levelPoints;
    [SerializeField] Color backgroundAtStart;
    [SerializeField] Color[] backgrounds;
    [SerializeField] float colorChangingTime;

    public static int level;
    float point;

    public delegate void LevelPass();
    public static event LevelPass OnLevelPass;

    void Start(){
        Camera.main.backgroundColor = backgroundAtStart;
    }

    void Update(){
        point = PlayerPrefs.GetInt("Point");
        SetOnLevelPass();
    }


    void ChangeColor(){
        StartCoroutine("ColorChanger");
    }

    IEnumerator ColorChanger(){
        float ElapsedTime = 0.0f;
        float TotalTime = colorChangingTime;

        var camera = Camera.main;
        Color current = Camera.main.backgroundColor;
        Color next = backgrounds[level - 1];

        while(ElapsedTime < TotalTime)
        {
            ElapsedTime += Time.deltaTime;
            camera.backgroundColor = Color.Lerp(current, next, (ElapsedTime / TotalTime));
            yield return new WaitForEndOfFrame();
        }

        ElapsedTime = 0;
        yield return null;
    }

    void SetOnLevelPass(){
        for(int i = 0; i < levelPoints.Length; i++)
        {
            if(point == levelPoints[i])
            {
                level = i + 1;
                OnLevelPass();
            }
        }
    }

    void CallLevelPassedOnce(){
        PlayerPrefs.SetInt("Point", PlayerPrefs.GetInt("Point") + 10);
    }

    void OnEnable(){
        OnLevelPass = null;
        OnLevelPass += CallLevelPassedOnce;
        OnLevelPass += ChangeColor;
    }
}