Build a web-based implementation of Conway's Game of Life. The end artifact is a visualization that fills the entire screen.

Ship a pure client-side app with no build step and no external dependencies: plain HTML, CSS, and JavaScript that runs by opening index.html directly in a browser.

Render the simulation on a single HTML canvas that always fills the entire browser viewport, and re-fits the grid whenever the window is resized.

Follow the standard Conway rules (B3/S23): a live cell with 2 or 3 live neighbors survives, a dead cell with exactly 3 live neighbors becomes alive, every other cell dies or stays dead.

The grid is toroidal: it wraps at all four edges, so patterns that move off one side reappear on the opposite side.

On first load, seed the board with a random live/dead pattern and start the simulation running automatically so something is alive and moving immediately.

Give the user controls to play/pause, advance a single generation while paused, randomize the board, and clear it to empty.

Let the user draw: clicking or click-dragging on the canvas toggles cells between alive and dead, so they can paint their own patterns.

Provide a speed control that adjusts how many generations are simulated per second.

Visual style: dark background with bright glowing living cells and a minimal, unobtrusive control overlay. Display a live generation counter and population count.