100% width does not look good :-(

Yeah, tell me about it
We learning it the hardway that we need to learn more about the CSS property: box-sizing
you’ll need to give your input and textarea this property
so you can add this code to your css:

.wpcf7 input, .wpcf7 textarea {
    box-sizing: border-box;
}

and if you want to remove the background of your captcha you can use this code:

.wpcf7-recaptcha {
    background: none !important;
}