Devlog 3: Draggable Windows

-Code Split: Moved JS to script.js to clean up the HTML.

-Window Dragging: Added mouse events to smoothly drag the window via a top header.

-Open/Close: Used JS to toggle display none and flex using click event listeners.

-CSS Classes: Replaced inline styles with reusable classes for easy future apps.

Next up: Building my first actual app inside the window!