Light and dark
hiy has a light mode and a dark mode, and a toggle to switch between them. Whichever you pick applies everywhere on the site, and a way to switch it is on every page too.
Where to find it
A small sun/moon circle sits in the bottom-right corner of most pages — the homepage, docs, the create flow, your dashboard. Click it and the whole page swaps themes right there; no menu to open first. Someone’s public twin page keeps its own copy of the same circle in its top nav instead: that page already has a floating ask bar living in that same corner, so the switch stays up top rather than crowding it.
Two other places offer the same switch, for whoever already has them open. Signed out — on the homepage, pricing, docs, or any other marketing page — open Resources in the header and pick Light mode or Dark mode at the bottom of the menu; on a phone, it’s the last row in the menu panel. Signed in, your account menu (the avatar in the dashboard’s rail, or the top bar on a phone) offers the same choice. Both name what you’ll switch to, not what you’re on now, so it reads “Light mode” while you’re still looking at the dark one — the corner toggle does the same with its icon, showing a sun while you’re in dark mode.
Both are the same setting. Switch it from the header, and your dashboard opens in whichever one you left it in.
It’s remembered on this device
Your choice is saved in the browser you made it in. Sign in on a different phone or laptop and hiy starts back on the default there, until you choose again on that device too.
hiy opens light by default
Light is what a first-time visitor sees — the homepage, the docs and your dashboard alike — even if their phone or computer is set to dark mode. hiy doesn’t read that system setting for its own pages; pick dark mode once and it’s remembered from then on, on that device. (The chat you embed on your own site is the exception: it follows the visitor’s device, because it lives on your page, not ours.)
Your agent’s colour is a different setting
Light and dark are about hiy, on your own screen. Your agent’s accent is about your agent, on everybody’s — and it is not on this toggle. It lives under Settings → Profile → Appearance (since 9 September 2026; it used to sit with the rules, so an older link or bookmark may still point there and still lands). Both it and the photo are covered on Your public profile.
Neither is affected by the light/dark choice above, and neither affects it: a visitor reading your page in their own dark mode sees your accent, not your theme.
Your embed doesn’t follow it
If you’ve put your twin’s chat on your own site (see Embedding), it ignores this setting entirely — yours and every visitor’s. It looks instead at whoever’s actually looking at it: their own device’s light or dark setting, the same signal most embedded widgets already follow. That’s deliberate. A choice you make on hiy.ai shouldn’t quietly follow you onto someone else’s page, and an embed that always matched your hiy.ai theme would do exactly that to every visitor who opens it.