Pinterest login with PHP and cURL not working

Question

I've been trying to use cURL to get into pinterest.com for the past 17 hours without success. I've tried countless and endless different approaches using only cURL.

My existing code simply brings me to the login page; it does not log in because the data is not uploaded.

The first code sends me to the login screen using USERPWD, but it doesn't log me in.

error_reporting(E_ALL); 
ini_set("display_errors", 1); 

$url = "https://www.pinterest.com/login/";

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6");
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);
curl_setopt($ch, CURLOPT_AUTOREFERER, 1);
curl_setopt($ch, CURLOPT_MAXREDIRS, 5);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10); 
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // allow https verification if true
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2); // check common name and verify with host name
curl_setopt($ch, CURLOPT_SSLVERSION,3); // 
curl_setopt($ch, CURLOPT_CAINFO, getcwd() . "pin.pem"); // allow ssl cert direct comparison
curl_setopt($ch, CURLOPT_COOKIESESSION, TRUE); // set new cookie session
curl_setopt($ch, CURLOPT_COOKIEJAR, "cookies.txt");
curl_setopt($ch, CURLOPT_COOKIEFILE, "cookies.txt");
curl_setopt($ch, CURLOPT_USERPWD, "email:password");

curl_setopt($ch, CURLOPT_SSLVERSION,3);

// grab URL and pass it to the browser
curl_exec($ch);

// close cURL connection, save cookie file, free up system resources
curl_close($ch);

And if I switch it from CURLOPT_USERPWD to,

curl_setopt($ch, CURLOPT_POSTFIELDS, 'username_or_email=$email&password=$password');

It just displays a blank page.

The pin.pem is the X.509 Certificate (PEM) file. Can someone please help me with this?