AmongUsRevamped/Patches/ChatControlPatch.cs

using InnerNet;
using System;
using UnityEngine;

// https://github.com/SuperNewRoles/SuperNewRoles/blob/master/SuperNewRoles/Patches/LobbyBehaviourPatch.cs
namespace HNSRevamped;

[HarmonyPatch(typeof(ChatController), nameof(ChatController.Update))]
internal static class ChatControllerUpdatePatch
{

    public static void Postfix(ChatController __instance)
    {
        if (Main.DarkTheme.Value)
        {
            __instance.freeChatField.background.color = new Color32(40, 40, 40, byte.MaxValue);

            __instance.quickChatField.background.color = new Color32(40, 40, 40, byte.MaxValue);
            __instance.quickChatField.text.color = Color.white;
        }
        else __instance.freeChatField.textArea.outputText.color = Color.black;
    }
}