widget inner margin & font size setting

Hi Catch Themes team, I am trying to create similar design site with https://dvcon.org/. My page url is http://dvcon-japan.com/2017/. Now I have trouble with right-side widget "開催概要". It should be same style with side widget "Expo Hours" on https://dvcon.org/, but I cannot remove margin around title "開催概要". And I would also like to modify its font size like main contents on left-side. Could you give me your advice? Thank you, Sumiko