Custom CSS styling tag

Hi, I am trying to style my captcha in my custom css area. What tag do I use? For example, the captcha area is .wpcf7-captchar and the text area is .wpcf7-text but I cant seem to be able to find one for the area that referrs to the area that displays numbers.

Please help

https://ww.wp.xz.cn/plugins/really-simple-captcha/