Hide default header image in index articles

<article>

    <header style="background-image:url('<?php if(has_post_thumbnail()) {

    <?php if(has_post_thumbnail()) {

        // A header configured specifically for this article

            the_post_thumbnail_url();

        } else {

        $url = get_the_post_thumbnail_url();

    } elseif(!$args["hide_default_header_image"]) {

        // Fall back to the default header (which can be configured site-wide, so we can't hardcode the URL)

            header_image();

        } ?>')">

        $url = get_header_image();

    } else {

        $url = null;

    }

    if($url !== null) {

        $style = "style=\"background-image:url('$url')\"";

    } else {

        $style = "";

    } ?>

    <header <?php echo $style; ?>>

        <?php if($args["link_title"]): ?>

            <h1><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h1>

        <?php else: ?>

            "show_published_date" => true,

            "show_modified_date" => false,

            "show_only_excerpt" => true,

            "link_title" => true

            "link_title" => true,

            "hide_default_header_image" => true

        ));

    } ?>