/* Apply bottom border to all input fields except the textarea */
.wpcf7-form-control.wpcf7-text,
.wpcf7-form-control.wpcf7-email,
.wpcf7-form-control.wpcf7-tel {
    border: none;
    border-bottom: 1px solid gray; 
}
.wpcf7-form-control.wpcf7-textarea {
    border: 1px solid gray; 
}