If you're looking at this demo and want the real thing on your own site, there are two install paths.
From JSR (recommended)
dune theme:install jsr:@dune/theme-sirocco@1.0.0 --activate
Pins an exact version in your site's import map — dune lockfile:sync
picks up the change, no manual file copying.
From a ZIP
Grab the release ZIP from the dune-themes GitHub
releases and extract it
into themes/sirocco/ in your site, then set:
# site.yaml
theme:
name: sirocco
Either path gets you the same theme — JSR is easier to keep updated, the ZIP works if you'd rather vendor the theme's code directly into your repo.