13 August 2026
This page lists every cookie and storage item the site uses, what each is for,
and how long it lasts. You can change your choice at any time with the
Cookie preferences link in the footer.
## How consent works here
Analytics and advertising are denied by default. Nothing non-essential is
set until you choose, using Google Consent Mode — the tags load but hold back
storage and personalisation until consent is granted.
That ordering is the point. A banner that appears after the cookies are already
set is decoration rather than compliance.
## Strictly necessary
These cannot be turned off. They store nothing that identifies you and are never
sent to a server.
| Name | Type | Purpose | Duration |
|---|---|---|---|
pbi-consent | Local storage | Remembers your cookie choice so you are not asked repeatedly | 12 months |
pbi-theme | Local storage | Remembers dark or light mode | Until cleared |
## Analytics — optional
Set only if you accept analytics.
| Name | Type | Purpose | Duration |
|---|---|---|---|
_ga | Cookie | Distinguishes one browser from another | 2 years |
_ga_* | Cookie | Keeps session state for Google Analytics 4 | 2 years |
We use these to see which lessons people read and which pages need work. The
data is aggregated and we cannot identify you from it.
## Advertising — optional
Set by Google AdSense only if you accept advertising cookies.
| Name | Type | Purpose | Duration |
|---|---|---|---|
__gads, __gpi | Cookie | Ad selection and frequency capping | Up to 13 months |
IDE, test_cookie | Cookie (doubleclick.net) | Measuring ad performance | Up to 13 months |
Ads still appear, because they fund the site. They are chosen from the content
of the page rather than from anything about you, and Google's data redaction is
switched on.
## Changing or withdrawing consent
- This site — the "Cookie preferences" link in the footer of every page
- Your browser — clearing site data removes everything stored here
- Google — adssettings.google.com controls ad personalisation across all sites
## If you block cookies entirely
The site works normally. Lessons, quizzes, flashcards and exams all run in your
browser and need no cookies. Only your theme choice and cookie decision will not
persist between visits.