Hi @alfred,

This CSS code should help you to solve the issue: 

#wpforo #wpforo-wrap .wpforo-login-wrap .wpf-field .wpf-field-wrap input[type="text"], #wpforo #wpforo-wrap .wpforo-login-wrap .wpf-field .wpf-field-wrap input[type="password"], #wpforo #wpforo-wrap .wpforo-login-wrap .wpf-field .wpf-field-wrap input[type="email"] {
   padding: 10px 20px 10px 34px !important;
   font-size: 14px;
}