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   1  <?php
   2  /**
   3   * Functions and definitions
   4   *
   5   * @link https://developer.wordpress.org/themes/basics/theme-functions/
   6   *
   7   * @package WordPress
   8   * @subpackage Twenty_Twenty_One
   9   * @since Twenty Twenty-One 1.0
  10   */
  11  
  12  // This theme requires WordPress 5.3 or later.
  13  if ( version_compare( $GLOBALS['wp_version'], '5.3', '<' ) ) {
  14      require get_template_directory() . '/inc/back-compat.php';
  15  }
  16  
  17  if ( ! function_exists( 'twenty_twenty_one_setup' ) ) {
  18      /**
  19       * Sets up theme defaults and registers support for various WordPress features.
  20       *
  21       * Note that this function is hooked into the after_setup_theme hook, which
  22       * runs before the init hook. The init hook is too late for some features, such
  23       * as indicating support for post thumbnails.
  24       *
  25       * @since Twenty Twenty-One 1.0
  26       *
  27       * @return void
  28       */
  29  	function twenty_twenty_one_setup() {
  30          /*
  31           * Make theme available for translation.
  32           * Translations can be filed in the /languages/ directory.
  33           * If you're building a theme based on Twenty Twenty-One, use a find and replace
  34           * to change 'twentytwentyone' to the name of your theme in all the template files.
  35           */
  36          load_theme_textdomain( 'twentytwentyone', get_template_directory() . '/languages' );
  37  
  38          // Add default posts and comments RSS feed links to head.
  39          add_theme_support( 'automatic-feed-links' );
  40  
  41          /*
  42           * Let WordPress manage the document title.
  43           * This theme does not use a hard-coded <title> tag in the document head,
  44           * WordPress will provide it for us.
  45           */
  46          add_theme_support( 'title-tag' );
  47  
  48          /**
  49           * Add post-formats support.
  50           */
  51          add_theme_support(
  52              'post-formats',
  53              array(
  54                  'link',
  55                  'aside',
  56                  'gallery',
  57                  'image',
  58                  'quote',
  59                  'status',
  60                  'video',
  61                  'audio',
  62                  'chat',
  63              )
  64          );
  65  
  66          /*
  67           * Enable support for Post Thumbnails on posts and pages.
  68           *
  69           * @link https://developer.wordpress.org/themes/functionality/featured-images-post-thumbnails/
  70           */
  71          add_theme_support( 'post-thumbnails' );
  72          set_post_thumbnail_size( 1568, 9999 );
  73  
  74          register_nav_menus(
  75              array(
  76                  'primary' => esc_html__( 'Primary menu', 'twentytwentyone' ),
  77                  'footer'  => esc_html__( 'Secondary menu', 'twentytwentyone' ),
  78              )
  79          );
  80  
  81          /*
  82           * Switch default core markup for search form, comment form, and comments
  83           * to output valid HTML5.
  84           */
  85          add_theme_support(
  86              'html5',
  87              array(
  88                  'comment-form',
  89                  'comment-list',
  90                  'gallery',
  91                  'caption',
  92                  'style',
  93                  'script',
  94                  'navigation-widgets',
  95              )
  96          );
  97  
  98          /*
  99           * Add support for core custom logo.
 100           *
 101           * @link https://codex.wordpress.org/Theme_Logo
 102           */
 103          $logo_width  = 300;
 104          $logo_height = 100;
 105  
 106          add_theme_support(
 107              'custom-logo',
 108              array(
 109                  'height'               => $logo_height,
 110                  'width'                => $logo_width,
 111                  'flex-width'           => true,
 112                  'flex-height'          => true,
 113                  'unlink-homepage-logo' => true,
 114              )
 115          );
 116  
 117          // Add theme support for selective refresh for widgets.
 118          add_theme_support( 'customize-selective-refresh-widgets' );
 119  
 120          // Add support for Block Styles.
 121          add_theme_support( 'wp-block-styles' );
 122  
 123          // Add support for full and wide align images.
 124          add_theme_support( 'align-wide' );
 125  
 126          // Add support for editor styles.
 127          add_theme_support( 'editor-styles' );
 128          $background_color = get_theme_mod( 'background_color', 'D1E4DD' );
 129          if ( 127 > Twenty_Twenty_One_Custom_Colors::get_relative_luminance_from_hex( $background_color ) ) {
 130              add_theme_support( 'dark-editor-style' );
 131          }
 132  
 133          $editor_stylesheet_path = './assets/css/style-editor.css';
 134  
 135          // Note, the is_IE global variable is defined by WordPress and is used
 136          // to detect if the current browser is internet explorer.
 137          global $is_IE;
 138          if ( $is_IE ) {
 139              $editor_stylesheet_path = './assets/css/ie-editor.css';
 140          }
 141  
 142          // Enqueue editor styles.
 143          add_editor_style( $editor_stylesheet_path );
 144  
 145          // Add custom editor font sizes.
 146          add_theme_support(
 147              'editor-font-sizes',
 148              array(
 149                  array(
 150                      'name'      => esc_html__( 'Extra small', 'twentytwentyone' ),
 151                      'shortName' => esc_html_x( 'XS', 'Font size', 'twentytwentyone' ),
 152                      'size'      => 16,
 153                      'slug'      => 'extra-small',
 154                  ),
 155                  array(
 156                      'name'      => esc_html__( 'Small', 'twentytwentyone' ),
 157                      'shortName' => esc_html_x( 'S', 'Font size', 'twentytwentyone' ),
 158                      'size'      => 18,
 159                      'slug'      => 'small',
 160                  ),
 161                  array(
 162                      'name'      => esc_html__( 'Normal', 'twentytwentyone' ),
 163                      'shortName' => esc_html_x( 'M', 'Font size', 'twentytwentyone' ),
 164                      'size'      => 20,
 165                      'slug'      => 'normal',
 166                  ),
 167                  array(
 168                      'name'      => esc_html__( 'Large', 'twentytwentyone' ),
 169                      'shortName' => esc_html_x( 'L', 'Font size', 'twentytwentyone' ),
 170                      'size'      => 24,
 171                      'slug'      => 'large',
 172                  ),
 173                  array(
 174                      'name'      => esc_html__( 'Extra large', 'twentytwentyone' ),
 175                      'shortName' => esc_html_x( 'XL', 'Font size', 'twentytwentyone' ),
 176                      'size'      => 40,
 177                      'slug'      => 'extra-large',
 178                  ),
 179                  array(
 180                      'name'      => esc_html__( 'Huge', 'twentytwentyone' ),
 181                      'shortName' => esc_html_x( 'XXL', 'Font size', 'twentytwentyone' ),
 182                      'size'      => 96,
 183                      'slug'      => 'huge',
 184                  ),
 185                  array(
 186                      'name'      => esc_html__( 'Gigantic', 'twentytwentyone' ),
 187                      'shortName' => esc_html_x( 'XXXL', 'Font size', 'twentytwentyone' ),
 188                      'size'      => 144,
 189                      'slug'      => 'gigantic',
 190                  ),
 191              )
 192          );
 193  
 194          // Custom background color.
 195          add_theme_support(
 196              'custom-background',
 197              array(
 198                  'default-color' => 'd1e4dd',
 199              )
 200          );
 201  
 202          // Editor color palette.
 203          $black     = '#000000';
 204          $dark_gray = '#28303D';
 205          $gray      = '#39414D';
 206          $green     = '#D1E4DD';
 207          $blue      = '#D1DFE4';
 208          $purple    = '#D1D1E4';
 209          $red       = '#E4D1D1';
 210          $orange    = '#E4DAD1';
 211          $yellow    = '#EEEADD';
 212          $white     = '#FFFFFF';
 213  
 214          add_theme_support(
 215              'editor-color-palette',
 216              array(
 217                  array(
 218                      'name'  => esc_html__( 'Black', 'twentytwentyone' ),
 219                      'slug'  => 'black',
 220                      'color' => $black,
 221                  ),
 222                  array(
 223                      'name'  => esc_html__( 'Dark gray', 'twentytwentyone' ),
 224                      'slug'  => 'dark-gray',
 225                      'color' => $dark_gray,
 226                  ),
 227                  array(
 228                      'name'  => esc_html__( 'Gray', 'twentytwentyone' ),
 229                      'slug'  => 'gray',
 230                      'color' => $gray,
 231                  ),
 232                  array(
 233                      'name'  => esc_html__( 'Green', 'twentytwentyone' ),
 234                      'slug'  => 'green',
 235                      'color' => $green,
 236                  ),
 237                  array(
 238                      'name'  => esc_html__( 'Blue', 'twentytwentyone' ),
 239                      'slug'  => 'blue',
 240                      'color' => $blue,
 241                  ),
 242                  array(
 243                      'name'  => esc_html__( 'Purple', 'twentytwentyone' ),
 244                      'slug'  => 'purple',
 245                      'color' => $purple,
 246                  ),
 247                  array(
 248                      'name'  => esc_html__( 'Red', 'twentytwentyone' ),
 249                      'slug'  => 'red',
 250                      'color' => $red,
 251                  ),
 252                  array(
 253                      'name'  => esc_html__( 'Orange', 'twentytwentyone' ),
 254                      'slug'  => 'orange',
 255                      'color' => $orange,
 256                  ),
 257                  array(
 258                      'name'  => esc_html__( 'Yellow', 'twentytwentyone' ),
 259                      'slug'  => 'yellow',
 260                      'color' => $yellow,
 261                  ),
 262                  array(
 263                      'name'  => esc_html__( 'White', 'twentytwentyone' ),
 264                      'slug'  => 'white',
 265                      'color' => $white,
 266                  ),
 267              )
 268          );
 269  
 270          add_theme_support(
 271              'editor-gradient-presets',
 272              array(
 273                  array(
 274                      'name'     => esc_html__( 'Purple to yellow', 'twentytwentyone' ),
 275                      'gradient' => 'linear-gradient(160deg, ' . $purple . ' 0%, ' . $yellow . ' 100%)',
 276                      'slug'     => 'purple-to-yellow',
 277                  ),
 278                  array(
 279                      'name'     => esc_html__( 'Yellow to purple', 'twentytwentyone' ),
 280                      'gradient' => 'linear-gradient(160deg, ' . $yellow . ' 0%, ' . $purple . ' 100%)',
 281                      'slug'     => 'yellow-to-purple',
 282                  ),
 283                  array(
 284                      'name'     => esc_html__( 'Green to yellow', 'twentytwentyone' ),
 285                      'gradient' => 'linear-gradient(160deg, ' . $green . ' 0%, ' . $yellow . ' 100%)',
 286                      'slug'     => 'green-to-yellow',
 287                  ),
 288                  array(
 289                      'name'     => esc_html__( 'Yellow to green', 'twentytwentyone' ),
 290                      'gradient' => 'linear-gradient(160deg, ' . $yellow . ' 0%, ' . $green . ' 100%)',
 291                      'slug'     => 'yellow-to-green',
 292                  ),
 293                  array(
 294                      'name'     => esc_html__( 'Red to yellow', 'twentytwentyone' ),
 295                      'gradient' => 'linear-gradient(160deg, ' . $red . ' 0%, ' . $yellow . ' 100%)',
 296                      'slug'     => 'red-to-yellow',
 297                  ),
 298                  array(
 299                      'name'     => esc_html__( 'Yellow to red', 'twentytwentyone' ),
 300                      'gradient' => 'linear-gradient(160deg, ' . $yellow . ' 0%, ' . $red . ' 100%)',
 301                      'slug'     => 'yellow-to-red',
 302                  ),
 303                  array(
 304                      'name'     => esc_html__( 'Purple to red', 'twentytwentyone' ),
 305                      'gradient' => 'linear-gradient(160deg, ' . $purple . ' 0%, ' . $red . ' 100%)',
 306                      'slug'     => 'purple-to-red',
 307                  ),
 308                  array(
 309                      'name'     => esc_html__( 'Red to purple', 'twentytwentyone' ),
 310                      'gradient' => 'linear-gradient(160deg, ' . $red . ' 0%, ' . $purple . ' 100%)',
 311                      'slug'     => 'red-to-purple',
 312                  ),
 313              )
 314          );
 315  
 316          /*
 317          * Adds starter content to highlight the theme on fresh sites.
 318          * This is done conditionally to avoid loading the starter content on every
 319          * page load, as it is a one-off operation only needed once in the customizer.
 320          */
 321          if ( is_customize_preview() ) {
 322              require get_template_directory() . '/inc/starter-content.php';
 323              add_theme_support( 'starter-content', twenty_twenty_one_get_starter_content() );
 324          }
 325  
 326          // Add support for responsive embedded content.
 327          add_theme_support( 'responsive-embeds' );
 328  
 329          // Add support for custom line height controls.
 330          add_theme_support( 'custom-line-height' );
 331  
 332          // Add support for experimental link color control.
 333          add_theme_support( 'experimental-link-color' );
 334  
 335          // Add support for experimental cover block spacing.
 336          add_theme_support( 'custom-spacing' );
 337  
 338          // Add support for custom units.
 339          // This was removed in WordPress 5.6 but is still required to properly support WP 5.5.
 340          add_theme_support( 'custom-units' );
 341  
 342          // Remove feed icon link from legacy RSS widget.
 343          add_filter( 'rss_widget_feed_link', '__return_false' );
 344      }
 345  }
 346  add_action( 'after_setup_theme', 'twenty_twenty_one_setup' );
 347  
 348  /**
 349   * Register widget area.
 350   *
 351   * @since Twenty Twenty-One 1.0
 352   *
 353   * @link https://developer.wordpress.org/themes/functionality/sidebars/#registering-a-sidebar
 354   *
 355   * @return void
 356   */
 357  function twenty_twenty_one_widgets_init() {
 358  
 359      register_sidebar(
 360          array(
 361              'name'          => esc_html__( 'Footer', 'twentytwentyone' ),
 362              'id'            => 'sidebar-1',
 363              'description'   => esc_html__( 'Add widgets here to appear in your footer.', 'twentytwentyone' ),
 364              'before_widget' => '<section id="%1$s" class="widget %2$s">',
 365              'after_widget'  => '</section>',
 366              'before_title'  => '<h2 class="widget-title">',
 367              'after_title'   => '</h2>',
 368          )
 369      );
 370  }
 371  add_action( 'widgets_init', 'twenty_twenty_one_widgets_init' );
 372  
 373  /**
 374   * Set the content width in pixels, based on the theme's design and stylesheet.
 375   *
 376   * Priority 0 to make it available to lower priority callbacks.
 377   *
 378   * @since Twenty Twenty-One 1.0
 379   *
 380   * @global int $content_width Content width.
 381   *
 382   * @return void
 383   */
 384  function twenty_twenty_one_content_width() {
 385      // This variable is intended to be overruled from themes.
 386      // Open WPCS issue: {@link https://github.com/WordPress-Coding-Standards/WordPress-Coding-Standards/issues/1043}.
 387      // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedVariableFound
 388      $GLOBALS['content_width'] = apply_filters( 'twenty_twenty_one_content_width', 750 );
 389  }
 390  add_action( 'after_setup_theme', 'twenty_twenty_one_content_width', 0 );
 391  
 392  /**
 393   * Enqueue scripts and styles.
 394   *
 395   * @since Twenty Twenty-One 1.0
 396   *
 397   * @return void
 398   */
 399  function twenty_twenty_one_scripts() {
 400      // Note, the is_IE global variable is defined by WordPress and is used
 401      // to detect if the current browser is internet explorer.
 402      global $is_IE, $wp_scripts;
 403      if ( $is_IE ) {
 404          // If IE 11 or below, use a flattened stylesheet with static values replacing CSS Variables.
 405          wp_enqueue_style( 'twenty-twenty-one-style', get_template_directory_uri() . '/assets/css/ie.css', array(), wp_get_theme()->get( 'Version' ) );
 406      } else {
 407          // If not IE, use the standard stylesheet.
 408          wp_enqueue_style( 'twenty-twenty-one-style', get_template_directory_uri() . '/style.css', array(), wp_get_theme()->get( 'Version' ) );
 409      }
 410  
 411      // RTL styles.
 412      wp_style_add_data( 'twenty-twenty-one-style', 'rtl', 'replace' );
 413  
 414      // Print styles.
 415      wp_enqueue_style( 'twenty-twenty-one-print-style', get_template_directory_uri() . '/assets/css/print.css', array(), wp_get_theme()->get( 'Version' ), 'print' );
 416  
 417      // Threaded comment reply styles.
 418      if ( is_singular() && comments_open() && get_option( 'thread_comments' ) ) {
 419          wp_enqueue_script( 'comment-reply' );
 420      }
 421  
 422      // Register the IE11 polyfill file.
 423      wp_register_script(
 424          'twenty-twenty-one-ie11-polyfills-asset',
 425          get_template_directory_uri() . '/assets/js/polyfills.js',
 426          array(),
 427          wp_get_theme()->get( 'Version' ),
 428          true
 429      );
 430  
 431      // Register the IE11 polyfill loader.
 432      wp_register_script(
 433          'twenty-twenty-one-ie11-polyfills',
 434          null,
 435          array(),
 436          wp_get_theme()->get( 'Version' ),
 437          true
 438      );
 439      wp_add_inline_script(
 440          'twenty-twenty-one-ie11-polyfills',
 441          wp_get_script_polyfill(
 442              $wp_scripts,
 443              array(
 444                  'Element.prototype.matches && Element.prototype.closest && window.NodeList && NodeList.prototype.forEach' => 'twenty-twenty-one-ie11-polyfills-asset',
 445              )
 446          )
 447      );
 448  
 449      // Main navigation scripts.
 450      if ( has_nav_menu( 'primary' ) ) {
 451          wp_enqueue_script(
 452              'twenty-twenty-one-primary-navigation-script',
 453              get_template_directory_uri() . '/assets/js/primary-navigation.js',
 454              array( 'twenty-twenty-one-ie11-polyfills' ),
 455              wp_get_theme()->get( 'Version' ),
 456              true
 457          );
 458      }
 459  
 460      // Responsive embeds script.
 461      wp_enqueue_script(
 462          'twenty-twenty-one-responsive-embeds-script',
 463          get_template_directory_uri() . '/assets/js/responsive-embeds.js',
 464          array( 'twenty-twenty-one-ie11-polyfills' ),
 465          wp_get_theme()->get( 'Version' ),
 466          true
 467      );
 468  }
 469  add_action( 'wp_enqueue_scripts', 'twenty_twenty_one_scripts' );
 470  
 471  /**
 472   * Enqueue block editor script.
 473   *
 474   * @since Twenty Twenty-One 1.0
 475   *
 476   * @return void
 477   */
 478  function twentytwentyone_block_editor_script() {
 479  
 480      wp_enqueue_script( 'twentytwentyone-editor', get_theme_file_uri( '/assets/js/editor.js' ), array( 'wp-blocks', 'wp-dom' ), wp_get_theme()->get( 'Version' ), true );
 481  }
 482  
 483  add_action( 'enqueue_block_editor_assets', 'twentytwentyone_block_editor_script' );
 484  
 485  /**
 486   * Fix skip link focus in IE11.
 487   *
 488   * This does not enqueue the script because it is tiny and because it is only for IE11,
 489   * thus it does not warrant having an entire dedicated blocking script being loaded.
 490   *
 491   * @since Twenty Twenty-One 1.0
 492   *
 493   * @link https://git.io/vWdr2
 494   */
 495  function twenty_twenty_one_skip_link_focus_fix() {
 496  
 497      // If SCRIPT_DEBUG is defined and true, print the unminified file.
 498      if ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) {
 499          echo '<script>';
 500          include get_template_directory() . '/assets/js/skip-link-focus-fix.js';
 501          echo '</script>';
 502      } else {
 503          // The following is minified via `npx terser --compress --mangle -- assets/js/skip-link-focus-fix.js`.
 504          ?>
 505          <script>
 506          /(trident|msie)/i.test(navigator.userAgent)&&document.getElementById&&window.addEventListener&&window.addEventListener("hashchange",(function(){var t,e=location.hash.substring(1);/^[A-z0-9_-]+$/.test(e)&&(t=document.getElementById(e))&&(/^(?:a|select|input|button|textarea)$/i.test(t.tagName)||(t.tabIndex=-1),t.focus())}),!1);
 507          </script>
 508          <?php
 509      }
 510  }
 511  add_action( 'wp_print_footer_scripts', 'twenty_twenty_one_skip_link_focus_fix' );
 512  
 513  /**
 514   * Enqueue non-latin language styles.
 515   *
 516   * @since Twenty Twenty-One 1.0
 517   *
 518   * @return void
 519   */
 520  function twenty_twenty_one_non_latin_languages() {
 521      $custom_css = twenty_twenty_one_get_non_latin_css( 'front-end' );
 522  
 523      if ( $custom_css ) {
 524          wp_add_inline_style( 'twenty-twenty-one-style', $custom_css );
 525      }
 526  }
 527  add_action( 'wp_enqueue_scripts', 'twenty_twenty_one_non_latin_languages' );
 528  
 529  // SVG Icons class.
 530  require get_template_directory() . '/classes/class-twenty-twenty-one-svg-icons.php';
 531  
 532  // Custom color classes.
 533  require get_template_directory() . '/classes/class-twenty-twenty-one-custom-colors.php';
 534  new Twenty_Twenty_One_Custom_Colors();
 535  
 536  // Enhance the theme by hooking into WordPress.
 537  require get_template_directory() . '/inc/template-functions.php';
 538  
 539  // Menu functions and filters.
 540  require get_template_directory() . '/inc/menu-functions.php';
 541  
 542  // Custom template tags for the theme.
 543  require get_template_directory() . '/inc/template-tags.php';
 544  
 545  // Customizer additions.
 546  require get_template_directory() . '/classes/class-twenty-twenty-one-customize.php';
 547  new Twenty_Twenty_One_Customize();
 548  
 549  // Block Patterns.
 550  require get_template_directory() . '/inc/block-patterns.php';
 551  
 552  // Block Styles.
 553  require get_template_directory() . '/inc/block-styles.php';
 554  
 555  // Dark Mode.
 556  require_once get_template_directory() . '/classes/class-twenty-twenty-one-dark-mode.php';
 557  new Twenty_Twenty_One_Dark_Mode();
 558  
 559  /**
 560   * Enqueue scripts for the customizer preview.
 561   *
 562   * @since Twenty Twenty-One 1.0
 563   *
 564   * @return void
 565   */
 566  function twentytwentyone_customize_preview_init() {
 567      wp_enqueue_script(
 568          'twentytwentyone-customize-helpers',
 569          get_theme_file_uri( '/assets/js/customize-helpers.js' ),
 570          array(),
 571          wp_get_theme()->get( 'Version' ),
 572          true
 573      );
 574  
 575      wp_enqueue_script(
 576          'twentytwentyone-customize-preview',
 577          get_theme_file_uri( '/assets/js/customize-preview.js' ),
 578          array( 'customize-preview', 'customize-selective-refresh', 'jquery', 'twentytwentyone-customize-helpers' ),
 579          wp_get_theme()->get( 'Version' ),
 580          true
 581      );
 582  }
 583  add_action( 'customize_preview_init', 'twentytwentyone_customize_preview_init' );
 584  
 585  /**
 586   * Enqueue scripts for the customizer.
 587   *
 588   * @since Twenty Twenty-One 1.0
 589   *
 590   * @return void
 591   */
 592  function twentytwentyone_customize_controls_enqueue_scripts() {
 593  
 594      wp_enqueue_script(
 595          'twentytwentyone-customize-helpers',
 596          get_theme_file_uri( '/assets/js/customize-helpers.js' ),
 597          array(),
 598          wp_get_theme()->get( 'Version' ),
 599          true
 600      );
 601  }
 602  add_action( 'customize_controls_enqueue_scripts', 'twentytwentyone_customize_controls_enqueue_scripts' );
 603  
 604  /**
 605   * Calculate classes for the main <html> element.
 606   *
 607   * @since Twenty Twenty-One 1.0
 608   *
 609   * @return void
 610   */
 611  function twentytwentyone_the_html_classes() {
 612      /**
 613       * Filters the classes for the main <html> element.
 614       *
 615       * @since Twenty Twenty-One 1.0
 616       *
 617       * @param string The list of classes. Default empty string.
 618       */
 619      $classes = apply_filters( 'twentytwentyone_html_classes', '' );
 620      if ( ! $classes ) {
 621          return;
 622      }
 623      echo 'class="' . esc_attr( $classes ) . '"';
 624  }
 625  
 626  /**
 627   * Add "is-IE" class to body if the user is on Internet Explorer.
 628   *
 629   * @since Twenty Twenty-One 1.0
 630   *
 631   * @return void
 632   */
 633  function twentytwentyone_add_ie_class() {
 634      ?>
 635      <script>
 636      if ( -1 !== navigator.userAgent.indexOf( 'MSIE' ) || -1 !== navigator.appVersion.indexOf( 'Trident/' ) ) {
 637          document.body.classList.add( 'is-IE' );
 638      }
 639      </script>
 640      <?php
 641  }
 642  add_action( 'wp_footer', 'twentytwentyone_add_ie_class' );
 643  
 644  if ( ! function_exists( 'wp_get_list_item_separator' ) ) :
 645      /**
 646       * Retrieves the list item separator based on the locale.
 647       *
 648       * Added for backward compatibility to support pre-6.0.0 WordPress versions.
 649       *
 650       * @since 6.0.0
 651       */
 652  	function wp_get_list_item_separator() {
 653          /* translators: Used between list items, there is a space after the comma. */
 654          return __( ', ', 'twentytwentyone' );
 655      }
 656  endif;