Custom Css on Theme APEX 23.1 won’t apply

I’ve added a custom css on my theme for JSON Configuration section of theme.
and Here’s what I do :

 {"customCSS":"",
"vars":{"@g_Accent-BG":"#505f6d",
"@g_Accent-OG":"#ececec",
"@g_Body-Title-BG":"#dee1e4",
"@l_Link-Base":"#337ac0",
"@g_Body-BG":"#f5f5f5"}}

But some of color like #505f6d won’t apply at all . Where did I go wrong ?