how to buy items on the market using diamonds?

[민하잡으러왔습니다]

hi I am playing on my PC via Steam, and it seems as if other players can buy stuff on the market using gems.
Is that only available for mobile users? If PC users can also buy stuff on the market using diamonds could you please explain how I do that?

[Helrato]

There shouldn't be anything limiting you from buying items with gems, the only limit is that you can't sell items for gems, until you've spent 600gems.
Try checking again, the gold button is to buy with gold, blue button is to buy with gems, if the item isn't for sale with gems, then you'll see a gold button and a greyed out button

[민하잡으러왔습니다]

so as a total i've spent over 600 (500 for craft slot expansion and 100 for chest opening) and I am still not seeing the choice to buy or sell items with diamonds on the market :(
i only see one option which is to buy or sell with gold

[Helrato]

For selling items for gems, when you get to the pricing menu, there's a small coin icon, tap on that icon to change it to gems.

As for buying, again, you should have both options. If you believe it's a bug or would prefer more people who can help, I'd advise going on their official discord server at
https://discord.gg/shoptitans