No color change

Hello!
i use Contact form in popup:
http://kdfeatured.com/animals/
scroll down and click button: “Upload now”
i change color from black to white in my form, but have black checkbox blank..
cant add white color to code:( help pls

<p><b><font color = “ffffff”>Your name</font></b>
[text* your-name] </p>

<p><b><font color = “ffffff”>Your e-mail</font></b>
[email* your-email] </p>

<p><b><font color = “ffffff”>Instagram username</font></b>
[text* your-instauser] </p>

<p><b><font color = “ffffff”>Instagram photo Link</font></b>
[url* url-336] </p>

<p><b><font color = “ffffff”>Check category</font></b>
<font color = “ffffff”>[select checkcat include_blank “Portait gallery” “Sony gallery” “Animals” “Landscapes” “Black & White”]</font></p>

<p><b><font color = “ffffff”>Upload your capture in High Quallity</font></b>

<font color = “ffffff”>[file your-file filetypes:gif|png|jpg|jpeg limit:2mb]</font></p>
<font color = “ffffff”>[mc4wp_checkbox]</font>
<p><font color = “ffffff”>[submit “Upload now”]</font></p>

https://wordpress.org/plugins/contact-form-7/