Add a unique body class for every admin page (including trash)

You can hook to admin_body_class:

add_filter( 'admin_body_class', 'set_admin_page_as_body_class' );

/**
 * Create a body class based on the current admin page.
 *
 * @param string $classes The current admin body classes.
 * @return string
 */
function set_admin_page_as_body_class( $classes ) {
    /**
     * For safety, I always check for get_current_screen before I use it.
     * May not be needed for how late `admin_body_class` is filtered.
     */
    if ( ! function_exists( 'get_current_screen' ) ) {
        return $classes;
    }

    $screen = get_current_screen();

    /**
     * Build an array of the parts you want.
     *
     * $screen->base gives you the page pase, so "edit.php"'s base is "edit"
     * get_query_var: https://codex.wordpress.org/Function_Reference/get_query_var
     */
    $vars   = [
        $screen->base,
        get_query_var( 'post_type' ),
        get_query_var( 'post_status' ),
        // etc.
    ];

    // array_filter will remove any "empty" elements.
    $vars  = array_filter( $vars );
    $class = implode( '-', $vars );

    // Don't add our class more than once.
    if ( false !== strpos( $classes, $class ) ) {
        return $classes;
    }

    $classes .= " {$class} ";
    return $classes;
}

Edit: your example URL, wp-admin/edit.php?post_status=trash&post_type=locations would generate a class like edit-locations-trash