Add liquid glass button options

config.php

@@ -213,6 +213,10 @@ if (!defined('RADIO_CONFIG_LOADED')) {
             // Recolor the page background to the album art's average color,
             // switching text light/dark for contrast.
             'dynamic_bg'    => radio_env_bool('THEME_DYNAMIC_BG', true),
+            // "Liquid Glass" refraction effect (menu/lyrics/mute/playpause
+            // buttons) in place of a flat THEME_ACCENT fill. See
+            // https://github.com/nikdelvin/liquid-glass
+            'liquid_glass'  => radio_env_bool('THEME_LIQUID_GLASS', false),
         ],
 
         // ---- Player ---------------------------------------------------
@@ -356,6 +360,7 @@ function radio_client_config() {
         'playerStyle'   => cfg('player.style'),
         'autoplay'      => cfg('player.autoplay'),
         'dynamicBg'     => cfg('theme.dynamic_bg'),
+        'liquidGlass'   => cfg('theme.liquid_glass'),
         'mediaSession'  => cfg('player.mediasession'),
         'dynamicMeta'   => cfg('player.dynamic_meta'),
         'siteName'      => cfg('site.name'),