Reply To: Add FitVids to GeneratePress for responsive videos

[Tom]

You could embed two separate videos at different sizes.

Wrap them in two different divs:

<div class="single-video">
    Video HTML for single post
</div>
<div class="category-video">
    Video HTML for category post
</div>

Then add this CSS:

.single .category-video {
    display: none;
}

body:not(.single) .single-video {
    display: none;
}

As for the category title font size, this is the CSS you need:

.page-header h1 {
    font-size: 25px;
}