How do I choose a theme for my agency site?
Choose the theme that resembles the rest of your site. A clean, text-led site suits ledger, minimal or editorial; a visual, image-heavy site suits image-hero or split-spotlight; a modern product-style site can carry glass, aurora or depth-3d. When unsure, start with ledger and change it later — your embed code stays the same.
Then pick a palette that uses your brand color for buttons and check that text on it is easy to read. The calculator's mode can follow the visitor's device setting with auto, so it looks right whether they browse in light or dark.