Thanks for your question.
The Bible condemns all sexual activity which has not been sanctified by marriage not just pre-marital sex. The word fornication in the Greek of the New Testament is the word "Porneia" from which we get our English word, "Pornography." Here is a link to some excellent information on the https://www.thisisyourbible.com website about this topic:
Marriage in the Lord
For this is the will of God, your sanctification: that you abstain from sexual immorality; that each one of you know how to control his own body in holiness and honor, not in the passion of lust like the Gentiles who do not know God;
(1 Thessalonians 4:3-5, ESV).
Flee from sexual immorality. Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body. Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God? You are not your own, for you were bought with a price. So glorify God in your body. (1 Corinthians 6:18-20)
Fornication and adultery in both the Old and New Testaments are used as a symbol of unfaithfulness to God. A casual and temporary approach to God is worthless and sinful. God demands commitment from us. So it is with marriage. The "Gentiles who know not God” have trivialized sexual activity to the point of absurdity. It used to be a question whether a man or a woman would exchange a chaste [by today’s standards] kiss after a first date. Now the question is whether or not they will end up in bed! The sexual union of a man and a woman must take place only in the security of the formal mutual commitment of marriage. Anything else is sinful and almost always ends badly for those indulging in it.
I hope that answers your question.