<h1 id="title">Hello</h1>
<button id="btn">Change title</button>
<script>
  document.getElementById("btn").addEventListener("click", () => {
    document.getElementById("title").textContent = "Hello, web developer!";
  });
</script>

Responsive design → layout adapts to screen size (media queries)
Framework/library → ready-made tools like React for building UIs
Component        → reusable piece of UI (a button, a card)
Event            → something that happens (click, submit, keypress)
Viewport         → the visible area of the page on a device
Accessibility    → making sites usable by everyone, including screen-reader users

// Fetch data from an API endpoint and read JSON
fetch("https://jsonplaceholder.typicode.com/users/1")
  .then(res => {
    console.log("Status:", res.status);    // 200
    return res.json();
  })
  .then(user => console.log(user.name, "-", user.email));

2xx success
  200 OK            request worked
  201 Created       new item saved
3xx redirect
  301 Moved         page has a new URL
4xx client error
  400 Bad Request   invalid input
  401 Unauthorized  login needed
  403 Forbidden     logged in but not allowed
  404 Not Found     wrong URL or missing item
5xx server error
  500 Internal Server Error  bug on the server

CREATE TABLE notes (id INTEGER PRIMARY KEY, text TEXT NOT NULL);

INSERT INTO notes (text) VALUES ('Learn HTTP');      -- Create
SELECT id, text FROM notes;                          -- Read
UPDATE notes SET text = 'Learn HTTP well' WHERE id = 1;  -- Update
DELETE FROM notes WHERE id = 1;                       -- Delete

Deployment        → putting your app on a server so others can use it
Environment       → where code runs: development, staging, production
Environment variable → setting stored outside code (e.g. API keys)
HTTPS certificate → enables encrypted connections
CDN               → network of servers that deliver files faster
Version control   → tracking code changes (Git)

Front               | Back
DOM                 | browser's live tree of page elements
Endpoint            | one URL in an API
404                 | resource not found
401 vs 403          | not logged in vs not allowed
CRUD                | create, read, update, delete
DNS                 | maps domain names to server addresses
Environment variable| setting kept outside the code
Responsive design   | layout adapts to screen size

Mini project to use every term
Build: a notes app
- HTML/CSS page with a form (frontend)
- JavaScript uses fetch to call your API (request/response, JSON)
- Backend endpoint saves notes (server, CRUD, database)
- Deploy it (hosting, domain, HTTPS, environment variables)
Write a README that uses each term correctly.

Explain a term in your own words
Term: ______
One-sentence meaning: ______________
Where it appears in a request's journey: browser / network / server / hosting
Tiny example: ______________