First time using CF7, can't modify style

Add the following to the style.css file in your child theme or add it to your css editor:

.wpcf7 input[type="submit"] {
    background: #006600;
}

* Note you can change the hex code (#006600) to a different green. Some choices are available here: https://www.color-hex.com/color/00ff00

EDITED

Even I tried adding following snippet(for select component) in the theme’s style.css as well as in the plugin’s style.css but that did NOT help :(.

.wpcf7 select{
font-size:10pt;
color:gray;
height:30px;
width:120px
}

Inputs appreciated.

@praj2312 As per the Forum Guidelines, please start a new topic.

@barnez

Thank you for your previous message.

I added your code to the css with the theme editor:
https://imagizer.imageshack.us/v2/735x338q90/923/QSNlXb.png

and also with the plugin Admin CSS:
https://imagizer.imageshack.us/v2/735x360q90/921/2Ugrjs.png

But still not working.