Well, being caught and being upset are not punishments. She's had a shock and felt some shame, but that's all. She's clearly been getting away with it for a little while, at least.
Why not chat to her in a day or two about what getting a criminal record means? If you have a DBS certificate for work, show it to her and explain how it matters. Look at some of the career choices that would be closed to her if she acquires a conviction. She's only a hop and a couple of steps away from adulthood now, so this ship needs to turn around quickly!
Since it was clothes, how about linking the punishment? Ask her to identify the items stolen so far and push a bit of you think she's holding back. Ask to see receipts or her statement if she uses a card. Then bag the items up and make her go with you to a charity shop and donate them. That will be memorable. Tell her from here on, for every item of clothing she comes home with, you will be asking for the receipt, and follow through. Unreceipted items to charity shop, as above.
Look through her makeup with her and check out whether she might have been shoplifting there, too. It's scarily expensive and way too easy to pocket. It's often where it starts.
Have the discussion about 'victimless' crime, retail 'shrinkage', the impact on honest customers, and how stealing is stealing, whoever it's from.
Finally, how about a bit of community service? She could volunteer at the local clothing bank or charity shop to do a bit of sorting, ironing, folding, pricing and display, to ram home that lots of people aren't able to afford high fashion items and lots of people are generous in giving, not taking. The shop need not know why, or what she did; this is for learning, not shaming.
The ultimate, if it ever happens again, is to remove access to all her clothing beyond underwear and school uniform for a week, go back to the charity shop with her and have her kit herself out from there with her own money.