I'm using APEX 23.1
In one of my applications, theme roller is not working and when I want to open it up , the page will be stuck in loading till I close it !
Here's what happen to me :

Also there's another problem . When I customize a theme and apply it to my application , some colors doesn't apply at all ! what makes it happen like this ?
My custom css that I use for theme style is this :
{"customCSS":"","vars":{"@g_Accent-BG":"#505f6d","@g_Accent-OG":"#ececec","@g_Body-Title-BG":"#dee1e4","@l_Link-Base":"#337ac0","@g_Body-BG":"#f5f5f5"}}
And the @g_Accent-BG
won't apply to app !