color on border in react-big-calendar

i'm using react-big-calendar and want to change the color of borders of all calendar but doesnt find how to do in the documentation, someone know how to do this styling?

Already tried in the dayPropGetter but doesnt work well, looks like have some space between the days:

i'm using this code in the style of dayPropGetter:

  const borderStyle = () => {
    return({
      style: {
        border: '1px solid',
        margin: 0,
        padding: 0
      },
    })}

and want to replace all the borders in the calendar. Someone can help?