Yes, your Credit Card details, and the Credit Card transaction are both safe.
We do not keep or store your credit card details on our servers except for the last 4 digits and the expiry date, both only used as an identifier. All transactions done on our site, including ongoing subscription payments, are done through our merchant Stripe.
All payments are completed using PCI compliant payment gateways over a secure internet connection via Stripe. Stripe has been audited by an independent PCI Qualified Security Assessor (QSA) and is certified as a PCI Level 1 Service Provider. This is the highest and most stringent level of certification available in the payments industry. All data and communication is encrypted, the service uses PGP keys for safe communication.