Child theme from direct URLs

I’m new to WordPress, so apologies in advance if this is a known issue, but could not find anything in FAQs or forums. I recently made a simple child theme from twentyfourteen, aiming to change the body text font for posts a bit. Strangely, the child theme works as expected when accessed through the main site URL https://www.rolandnilsson.net, but when accessed through a direct URL for a post, such as this one, it reverts to the parent’s font setting. What’s up?

Here is the child’s style.css:

/*
 Theme Name:   Twenty Fourteen Child
 Author:       Roland Nilsson
 Author URI:   https://www.rolandnilsson.net
 Template:     twentyfourteen
*/

#main-content p  {
    font-family: book-antiqua, palatino, times-new-roman, serif;
    text-align: justify;
    text-justify: inter-word;
    hyphens: auto;
}

And this is functions.php (from the codex):

<?php
function theme_enqueue_styles() {
    $parent_style = 'twentyfourteen';
    wp_enqueue_style( $parent_style, get_template_directory_uri() . '/style.css' );
    wp_enqueue_style( 'twentyfourteen-child',
        get_stylesheet_directory_uri() . '/style.css',
        array( $parent_style )
    );
}
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
?>

I looked at the HTML generated and it does seem to use twentyfourteen-child/style.css in some places. Perhaps the CSS is not correct?

Many thanks in advance for any help.