Small Design/CSS changes to a Google Chart

I have made a custom Google Chart using the Google Visualization API. I am looking to add some custom CSS to make some small design changes to the chart. The CSS/Design changes I am looking to make are: 1) Change the color/width of the border for the points on mouse-over. I have added the CSS to change the point color fill to black (this is outlined in the example below) but am having a hard time getting the border to change. 2) Change the gridlines to dashed lines. I know how to change the color through the 'var options' but assume that getting them dashed is through CSS. The code for this can be found here: [login to view URL]