public static class Logger
{
    private static readonly string LogFile = "app_log.txt";

    public static void Log(string name, object? value)
    {
        string valStr = value == null ? "null" : value.ToString();
        var line = $"[{DateTime.Now:HH:mm:ss}] {name} = {valStr}";
        File.AppendAllText(LogFile, line + Environment.NewLine);
        Console.WriteLine(line);
    }
}