2.3.0
· Fixed: playlists used with earlier versions not starting study mode. The "I left study mode" flag lived in the tab's sessionStorage and survived reloads and restored sessions. It is now in memory only, so it lasts until the page reloads; old flags are removed on startup.
· New: toolbar popup (on / off / automatic per playlist, remembered), with the same Alt+Shift+S shortcut.
· New: a "Study mode" chip appears for a few seconds on borderline playlists (some study evidence, no music/gaming/vlog signals).
· Changed: a "not a study playlist" verdict is remembered for a day (instant, no cover next time); the first time a playlist is seen, YouTube is covered for the second it takes to judge it.
· Fixed: YouTube's page (playlist panel, description, etc.) flashing while a lecture loads or changes: the page is hidden by CSS (html.sm-act) for the whole session, classes are restored instantly if YouTube rewrites them, and a replaced player never leaves a stale copy in the slot. Tested: no uncovered moment across a lecture change and a player rebuild.
· Improved: numbered lecture-length series ("Kanji 5: …") count as study evidence; UU… channel-upload lists are accepted; playlists must have a full-length id (no more WL / LL surprises).

2.2.2 - Complete UI Overhaul
· New: full-screen player with ambient color in the letterbox bars, a progress bar that paints itself with the lecture's color, and idle auto-hiding chrome.
· New: logo + lecture title pill (top-left). The logo talks in a thought bubble: encouragement plus "notes ready" and "quiz ready" notices.
· New: playlist glides out from the left edge, questions from the right edge (progressive color blur behind each).
· New: notes and quiz rise over the video as you scroll while a color blur takes over; floating "back to the lecture" button.
· New: first-run welcome tour (replay by clicking the logo).
· Fixed: the extension no longer applies to non-study playlists. Detection needs real evidence and is vetoed by music/gaming/vlog signals; length alone never qualifies; the launcher only shows on recognised study playlists; earlier guesses are discarded. Alt+Shift+S forces study mode on a playlist that was missed.
· Improved: no veil or changes on unknown playlists until they are recognised; smoother lecture switching.

2.2.0 - Complete UI Overhaul
· New: full-screen player with ambient color in the letterbox bars, a progress bar that paints itself with the lecture's color over time, and idle auto-hiding chrome.
· New: logo + lecture title pill (top-left). The logo talks: encouragement at 25% / 50% / 75% / finish, plus "notes ready" and "quiz ready" notices.
· New: playlist glides out from the left edge, questions from the right edge (progressive colour blur behind each).
· New: notes and quiz rise over the video as you scroll while a colour blur takes over; floating "back to the lecture" button.
· New: first-run welcome tour (replay by clicking the logo).
· Fixed: the extension no longer applies to non-study playlists. Detection needs real evidence and is vetoed by music/gaming/vlog signals; length alone never qualifies; the launcher only shows on recognised study playlists; earlier guesses are discarded. Alt+Shift+S forces study mode on a playlist that was missed.
· Improved: no veil or changes on unknown playlists until they are recognised; smoother lecture switching.

· New: Quiz panel beside the notes. Generates 5 questions at 75% of the lecture, instant right/wrong feedback, explanation under each answer, progress pips and a final score with retry.
· New: Chapters drawn on the progress bar, with titles in the hover tooltip.
· New: Per-lecture dynamic colour theme applied to the background, text and Ask box with smooth transitions and a remembered last theme.
· New: Collapsible notes panel (state remembered).
· New: Updated logo, shown as a tinted cut-out in the top-left corner, in the launcher button and on the loading veil.
· Changed: "Questions?" heading is right-aligned to the chat panel.
· Faster: pre-built UI, pre-opened Ask panel, quicker answer detection, playlist diffing, cached element refs, throttled background work, GPU-friendly progress bar.