Can't change color of workspaces icons

[KiraKyatto]

Hello, I recently tried to configure waybar on my arch hyprland but I'm not able to change the base color of the workspace icon. Here are my config files :

config :

{
        //Position TOP
        "layer": "top",
        "margin-top": 14,
        "margin-bottom": 0,

        //Load modules
        "include":["~/.config/waybar/modules.json"],

        //Modules LEFT
        "modules-left":[
                "clock",
                "wlr/taskbar",
        ],

        //Modules CENTER
        "modules-center":[
                "hyprland/workspaces",
        ],
}

style.css :

@import "/home/alex/.cache/wal/colors-waybar.css";

* {
        border: none;
        border-radius: 0;
        font-size: 18px;
        background: transparent;
}

#workspaces button {
        padding: 0 5px;
        color: @color3;
}

.modules-center {
        background-color: @color1;
        border-radius: 15px;
        padding: 0 10px;
}

modules.json :

{
        "clock":{
                "tooltip": true,
        },
        "hyprland/workspaces":{
                "persistent-workspaces": {"DP-1":[1,2,3], "HDMI-A-1":[1,2,3]},
                "format": "{icon}",
                "format-icons":{
                        "active": "",  //these two are icons from nerd fonts
                        "default": ""
                },
        },
}

Thanks to whoever tries to help me.