TheriapolisV3/Theriapolis.Desktop/Program.cs

using Theriapolis.Game;

// Resolve content directories relative to the executable.
//   Distribution: Data/ and Gfx/ sit next to the exe (absolute path)
//   Development:  walk up from the exe to find Content/Data and Content/Gfx
string dataDir = ResolveContentDir("Data");
string gfxDir  = ResolveContentDir("Gfx");

static string ResolveContentDir(string subdir)
{
    // 1. "<subdir>" next to the executable — distribution layout
    string local = Path.Combine(AppContext.BaseDirectory, subdir);
    if (Directory.Exists(local)) return local;

    // 2. Walk up from the exe to find Content/<subdir> — development layout.
    //    Trim the trailing separator first: on Windows AppContext.BaseDirectory ends
    //    with '\', and GetDirectoryName on a trailing-slash path strips the slash
    //    without ascending, wasting one iteration.
    string? dir = AppContext.BaseDirectory.TrimEnd(
        Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
    for (int i = 0; i < 6; i++)
    {
        if (dir is null) break;
        string candidate = Path.Combine(dir, "Content", subdir);
        if (Directory.Exists(candidate)) return candidate;
        dir = Path.GetDirectoryName(dir);
    }

    return local; // missing-file errors will surface from the consumer with the bad path
}

using var game = new Game1
{
    ContentDataDirectory = dataDir,
    ContentGfxDirectory  = gfxDir,
};
game.Run();