Challenge 3: Add a Dependency — Solution Walkthrough

1. Open app/build.gradle.kts.
2. Find the "dependencies { }" block.
3. Add a new line inside it:
     implementation("com.google.android.material:material:1.11.0")
   (or whatever the current stable version is — Android Studio's editor
   will often suggest the latest version via autocomplete).
4. Save the file. A banner should appear at the top of the editor saying
   "Gradle files have changed since last project sync" with a
   "Sync Now" link — click it. (Android Studio may also auto-sync
   depending on settings.)
5. Wait for the sync to complete (progress bar at the bottom) and
   confirm there are no red error messages in the "Build" panel.

// What "Sync Now" actually does:
// Gradle re-reads build.gradle.kts, resolves the newly added dependency
// coordinate (group:artifact:version) against its configured Maven
// repositories (Google's Maven repo and Maven Central, by default),
// downloads the library's .aar/.jar file plus its own transitive
// dependencies if not already cached locally, and makes all of it
// available to the IDE's autocomplete and the next build — directly
// equivalent to what "npm install" does after adding a new entry to
// package.json's dependencies, just resolving against Maven repositories
// instead of the npm registry.

Expected result:
The sync completes with no errors, and material design classes (e.g.
com.google.android.material.button.MaterialButton) become available for
autocomplete in Kotlin files and as a valid tag in XML layouts.

Notes:
- If the sync fails, the most common causes at this stage are a typo in
  the dependency coordinate or no internet connection to reach the Maven
  repositories.