Can I display FAQs based on Product?

Hello,

2) You can put your custom CSS rules to site.css. It is perfect place for it.
http://www.amember.com/docs/Site.css_file

1) I am afraid it is not possible to do by default but aMember is flexible enough and allow to change almost anything without any changes in core files. Here is approach that allow you to do it:

Put the following code in site.php and it will do the trick. You can update it further according your requirements:
http://www.amember.com/docs/Site.php_file

PHP:

Am_Di::getInstance()->hook->add(Am_Event::BEFORE_RENDER, function(Am_Event $e) {
    $product_to_faq = array(
        1 => array(1,2,3)
    );
   
    if (strpos($e->getTemplateName(), 'helpdesk/faq.phtml')!==false) {
       
        $u = $e->getDi()->user;
        $hasAccess = array();
        foreach ($e->getDi()->user->getActiveProductIds() as $id) {
            $hasAccess = array_merge($hasAccess, isset($product_to_faq[$id]) ? $product_to_faq[$id] : array());
        }
       
        $v = $e->getView();
        foreach ($v->faq as $k => $p) {
            if (!in_array($p->pk(), $hasAccess)) {
                unset($v->faq[$k]);
            }
        }
    }
});

I can implement plugin that will incorporate such feature to admin UI if necessary.
Please contact us in heldpesk for a quote
https://www.amember.com/support

In FAQ section in admin interface you have HTML editor for each item so you can use any HTML code for your items.

I suggest to wrap it with div with some class ie.:

HTML:

<div class="my-faq-item">
    <p>text</p>
    <p>text</p>
</div>

and then use CSS cascade:

Code:

.my-faq-item p {color: green;}