easyblog video embed

when I add an youtube video block into easyblog it will only give me the small 400 px size.
when i change the numbers it leaves it the same small size

i tried this code in my custom css and it didn't do anything

/*make EB video better responsive*/

.legacy-video-container {position: relative;padding-bottom: 56.25%;padding-top: 30px;height: 0;overflow: hidden;}

.legacy-video-container iframe, .legacy-video-container object, .legacy-video-container embed {position: absolute;top: 0;left: 0;width: 100%;height: 100%;}