How to wish your friends a happy Lent and Ramadan?

This week marks the start of Ramadan and Lent. I'm an atheist, but I usually wish a couple of friends a happy Ramadan. I think they really appreciate the gesture and it's not inappropriate... sometimes they invite me for a meal during this time. I try to be polite; these are lovely moments that belong only to them and that they're proud of.

Even though I don't fully understand it because I don't experience it, I grasp its importance... last year was difficult; she was expecting a baby during Ramadan, and I was fascinated by her courage, devotion, and introspection during that time.

As for Lent, I'm not sure. My other friend is Georgian and Orthodox, and I don't know how to phrase things or what kind of message I can send her for this important period.I'm an atheist, but I can clearly see that religion plays a significant role in their lives. Even if their religion is different, it's something important that guides them and is part of their daily lives.

If it's possible, if there's a specific phrase or a gesture of gratitude, I'm all for it. If I have to refrain for any reason, I will too.