How do I change the theme, currency, page size, and icons?

These live in your Account settings (and a couple have quick toggles in the navigation rail).

• Theme — switch between light and dark mode. There's a quick toggle at the bottom of the navigation rail, and the choice is remembered for next time.
• Icon pack — choose the icon style used around the app.
• Default currency — the currency your prices and totals display in.
• Preferred view mode — whether lists like your collection open in list or grid view by default.
• Items per page — how many rows load at a time in lists (you can set this anywhere from 1 to 100).

Your preferences follow your account, so they apply on whatever device you sign in from.