Changelog

New

• A sidebar instead of the top bar. Sections are grouped by what you are doing: "Learn" holds courses, the roadmap, "My progress" and, when C++ is your stack, Core Guidelines; "Interviews" holds the simulator, questions and the resume check; then "AI tools", and "Journal" with the blog and IT news. At the bottom are pricing, the Telegram community, language, theme and a "…" menu with your account, feedback and support for the project. On screens 1260 px and wider the sidebar expands or folds into a narrow icon rail, and your choice is remembered in the browser; on lessons, the roadmap, the blog and the feed it starts folded. Narrower screens get the icon rail, and a phone gets a top bar with search and five tabs at the bottom: Learn, Interview, Search, Journal and Menu. ⌘K or Ctrl K opens search too.
• My stack. A "My stack" button now sits under search. Pick one of 16 stacks — 10 languages and 6 tracks; C++ has a "Focus in C++" switch with an Unreal Engine option. From then on Roadmap, Questions and My progress go straight to your stack, the simulator opens on it, and /progress opens on its tab. Signed in, the stack is saved to your account and is the same on every device; a guest's stack lives in the browser and moves to the account at sign-in. Opening another stack's page from a link does not change your choice. Every account sees a "Pick your stack!" window once; "I'll pick later" closes it for good.
• A light theme. The site can now be viewed in light colours. The theme button at the bottom of the sidebar (on a phone, under Menu) offers System, Light and Dark: System follows your device, and inside Telegram it follows Telegram's theme. The theme is applied before the page paints, so there is no flash of the other colour, and a change shows at once in every open tab.
• Three new free courses: Go, Python and JavaScript. "Go for Beginners" has 17 themes and 159 lessons (69 theory, 56 quizzes, 34 exercises) plus two optional starred exercises, from your first program through slices, maps, interfaces, errors, goroutines and channels to a "From a file to a project" theme on modules and go test, and a final project. "Python Core" has 16 themes and 146 lessons (63 theory, 52 quizzes, 31 exercises), from your first program to classes, exceptions, modules, files and generators. "JavaScript for Beginners" has 16 themes and 172 lessons (76 theory, 49 quizzes, 47 exercises), from your first program to closures, classes, errors and async code. As in the C++ course, you can read lessons and answer quizzes without an account, and exercises are checked by tests right in your browser.
• "Machine Learning from Scratch". 19 themes and 217 lessons (88 theory, 91 quizzes, 38 exercises) on classical machine learning in Python: from NumPy and pandas through regression, trees, boosting, clustering and neural networks to shipping a model and a final project. Exercises with numpy, pandas and scikit-learn run right in your browser; loading the libraries the first time takes up to a minute. The first two themes, "What Machine Learning Is" and "NumPy and pandas" (21 lessons), are free; the rest comes with the Basic plan.
• Exercises are checked in the cloud. "Run tests" in the browser now checks only the visible tests, and a lesson counts after "Submit for checking": your code runs on our server in an isolated environment with no network. Go is checked with the race detector, C++ with memory and undefined-behaviour checks, and some Go exercises also have hidden tests — a failure shows the test number and a hint, never its data. Checking needs an account and counts toward the same run limit.
• Step-through traces and live diagrams in lessons. In the Go, C++, Python and JavaScript courses you can step through code: "Next step" and "Back" highlight the current line and show variables, function calls and output. The hardest idea of a chapter in the Go and C++ courses gets a live diagram with "Reset" and "Show answer" — how append grows a slice, how a map is laid out, how std::vector moves to new memory, how a virtual call is dispatched. Every chapter of the C++, Go, Python and JavaScript courses opens with an illustration and a "What you'll learn" box.
• IT Abyss in your AI chat. You can now take IT Abyss AI interviews and quizzes right in Claude (web, desktop and mobile), ChatGPT (Business, Enterprise and Edu), Claude Code and Codex: connect IT Abyss with the steps on the /mcp page — "Interviews in AI chat" in the AI tools group. The results go to your progress. Without a subscription: 2 AI interviews, and quizzes from the same 10 sessions as on the website, once; with one, no round limit.
• Support the project. The "…" menu gains "Support IT Abyss": a one-time donation of any amount through Tribute in rubles or by card in any currency. Free-plan users sometimes see this window on its own — at most once a day and only on content pages; "Not now — remind me in a month" hides it for 30 days.

Improved

• Course quizzes. A quiz lesson can now hold up to three questions ("Question 2 of 3"), and you can reopen an answered one to look at it again. The end of the lesson shows how many answers were right and which questions you missed. In the Go course every answer is followed by why the right option is right and, under wrong options, what is wrong with them; 8 new quizzes cover classic interview traps, and 12 older questions now ask "what does this code print".
• Catalog and course pages. Courses sit on two shelves — "Programming languages from scratch" and "Machine learning". A course and each of its themes show an estimated time, a paid course shows its plan badge, and if your plan already covers it you see "Included in your plan"; free themes and lessons of a paid course are marked "Free". A course page gains a "Set up your computer" panel with links to what to download to run the code yourself; it folds itself once you have progress.
• Exercise results. Each test gets its own row with "Got", "Expected" and the program output. In Go, missing standard-library imports are added for you. Python now has syntax highlighting in exercises and the simulator, and JavaScript in courses.
• New interview questions. 48 junior questions for Go, 45 for Python, 38 for JavaScript and 83 for machine learning, which also gains 9 topics.
• Home page. Under "Start an interview" a "Try for free" block links to AI interviews, the resume check and language courses. Further down there is a courses block and a "News" column with the five latest items from the feed.
• Clearer about what is free. The simulator, courses and resume-check landings, the interviews page and pricing now describe the free part the same way: 25 Abyss Token — enough for one 9-question text AI interview — and 10 Quiz sessions, one-time; voice interviews come with a plan; the first resume check is free after sign-up. On pricing, "Most popular" is now "Recommended", and the ruble payment option shows prices in rubles only.
• News feed. The machine-learning category became the "Machine learning" subcategory of AI. Every card shows whether the article is in RU or EN, and news about a programming language links to "… interview questions". "Show more" keeps the subcategory row in place.
• Roadmap. The stack name in the title is now a menu: "Roadmap: Go ▾" switches the stack. The Go beginner path on the map is more compact.
• Small things on phones. The cookie notice takes one line, and categories in the feed and in the home-page news wrap onto a new line instead of hiding past the edge of the screen.

Fixed

• The roadmap can no longer be dragged off screen. Panning, zooming and resizing the window always keep at least one card in view.
• print() output in Python exercises. It used to get lost; it now shows in the results.
• Moving between lessons. The lesson contents no longer reset their scroll, and text no longer re-wraps when a scrollbar appears.