If you are using the Contact Form 7 WordPress plugin and struggling to get the input box sizes to all be the same length in all browsers you can add the following code to your style sheet.

#wpcf7-f59-w1-o1 input[type=text] {
width: 85%;
}

#wpcf7-f59-w1-o1 input[type=email] {
width: 85%;
}

#wpcf7-f59-w1-o1 textarea {
width: 85%;
height: 80px;
}

This will then allow you to set the width, in the example we have used 85% to give a little space around the input boxes.

Note: Check that these lines have not already been added in the style.css file for the main theme.