public Vector2 boxSize;
    public Vector2 boxOffset;
    publicLayerMask groundLayer;

    bool IsGrounded;

    void Update()
    {
        CheckGround();
    }

    void CheckGround()
    {
        Vector2 boxCenter = (Vector2)transform.position + boxOffset;

        IsGrounded = Physics2D.OverlapBox(boxCenter, boxSize, 0f, groundLayer);
    }

    void OnDrawGizmosSelected()
    {
        Gizmos.color = IsGrounded ? Color.green : Color.red;

        Vector2 boxCenter = (Vector2)transform.position + boxOffset;
        Gizmos.DrawWireCube(boxCenter, boxSize);
    }