Create Purple Button and increase the textfield boxes

https://cloakedinmodesty.com/contact/

this is my contact us page and I want the send button big and purple background with the send font awesome icon aligned and the textfield boxes bigger .Below are my css code and html code and also after using this html code in the mail setting reply to email in additional headers there is error saying invalid mailbox syntax:

<label> Name (required)
[text* text-599  class:cf7-fa-icon-fa-user class:cf7-label-My_Name]</label>
 
<label>E-mail (required)
[text* text-599 class:cf7-fa-icon-fa-envelope class:cf7-label-Email]</label>

<label>Subject (required)
[text* text-599 class:cf7-fa-icon-fa-folder class:cf7-label-Subject]</label>

<label>Message (required)
[textarea* text-599 class:cf7-fa-icon-fa-pencil class:cf7-label-Message]</label>

 
[submit class:cf7-submit class:submit-icon-fa-send "Send"]

CSS CODE

.wpcf7 .wpcf7-text,
.wpcf7 .wpcf7-textarea{                 
  text-indent: 15px;                    
}
.wpcf7 p{ position: relative; }
.wpcf7 p .fa{
  position: absolute;
  color: #7b599b;
  z-index: 100;
  font-size: 18px;
  top: 33%;
  left: 1.5%;
}
.wpcf7 p .fa-pencil{ top: 5%; left: 1.5%}