x axis goes back after 90 unity code example

Example: x angle oes back after 90 unity

public static float CalcEulerSafeX(float x)
     {
         if (x >= -90 && x <= 90)
             return x;
         x = x % 180;
         if (x > 0)
             x -= 180;
         else
             x += 180;
         return x;
     }