This is a submission for the DEV April Fools Challenge
What I Built
A precision challenge where you drag a <div> to the exact center of the screen. The success threshold is 0.0001 pixels. For context, a single pixel on a Retina display is about 0.5 physical pixels. The threshold is 5,000x smaller than that.
The global success counter reads 0. It will always read 0.
The interface is a full JARVIS-style holographic HUD dashboard with:
- Real-time deviation readouts (X, Y, total distance) updating at 60fps
- Precision meter with logarithmic scale (INSANE / CLOSE / WARM / MEH / LOST)
- Global leaderboard pulling top 20 closest attempts from Neon Postgres
- Live feed showing recent attempts from players worldwide
- Radar sweep with live player blips
- Earth Scale that maps your pixel error to real-world distance (your 2.4px miss = 49,873km on Earth)
- 2,500+ handwritten quotes based on how far off you are
- Share cards for every platform (1080x1080 Retina PNG)
- Hidden 418 teapot easter egg (particle cloud, draggable, zoomable, with steam)
- Light/dark mode
Anti-value proposition: This app takes the most solved problem in CSS and makes it unsolvable.
Demo
Drag the div. Submit your attempt. Share your score. Join the leaderboard of people who almost centered a div but didn't.
When you submit, a HUD result card slams in with a glitch-text "NOT CENTERED" verdict, your exact deviation to 6 decimal places, your global rank, and a reminder that you were 47,000x over the threshold.
The share text includes your Earth Scale result:
I got 7.975985px from center in "Can You Center This Div?"
If the target was Earth, I missed by 689km.
"700km. The distance from Amsterdam to Berlin."
Rank #26 of 48. Successes: 0. Ever.
Code
raxxostudios
/
center-this-div
Can You Center This Div? The most over-engineered centering challenge. JARVIS HUD. 0.0001px threshold. Global leaderboard. Successes: 0. Ever.
Can You Center This Div?
The most over-engineered centering challenge on the internet.
Success threshold: 0.0001px. Global successes: 0. Ever
Play Now | DEV Challenge | RAXXO Studios
What Is This
Drag a <div> to the exact center of the screen. That's it.
The catch: the success threshold is 0.0001 pixels, roughly 5,000x smaller than a single pixel on a Retina display. The global success counter reads 0. It will always read 0.
The HUD
Because if you're going to fail at centering a div, you should fail beautifully.
- Real-time deviation readouts (X, Y, total distance) at 60fps
- Precision meter with logarithmic scale (INSANE / CLOSE / WARM / MEH / LOST)
- Global leaderboard tracking closest attempts worldwide
- Live feed showing recent attempts from other players
- Radar sweep with live player blips and pulsing glow
- Earth Scale mapping your pixel error to real-world distance
- 2,500+ unique quotes based on…
Dead simple stack, wildly overengineered execution:
- Next.js 16 + React 19 + TypeScript
- Neon Postgres (serverless) for global leaderboard and stats
- Phosphor Icons for HUD iconography
- Pure CSS doing 90% of the visual work (no animation libraries)
- Pointer Events API with drag offset tracking for sub-pixel precision
- Canvas API for generating share card images
The entire game logic lives in one custom hook: useDivCentering. Around 200 lines. The HUD is all CSS custom properties, perspective transforms, conic-gradient radar sweeps, and keyframe animations for scan lines, ring pulses, and floating labels.
How I Built It
The game measures Euclidean distance from the div center to the target center. Results are stored as REAL in Postgres, giving about 7 significant digits of precision. More than enough to confirm you failed.
The Earth Scale converts pixel deviation to kilometers using deviationPx * (40,075km / targetWidthPx). Each distance tier has 10 handwritten quotes. Getting within 1px maps to about 200km. Getting within 0.1px maps to about 20km. Getting within 0.0001px maps to about 20 meters. Nobody has gotten there.
The 418 easter egg renders a Utah teapot as a 3D point cloud (~2,500 particles) with full drag rotation, scroll zoom, pinch zoom on mobile, and steam particles rising from the spout. All pure canvas, no 3D libraries.
Anti-cheat: submissions with both X and Y deviation below 0.3px are rejected with HTTP 418 ("I'm a teapot. Nice try."). The success counter never increments. It is hardcoded to stay at 0 forever.
The leaderboard is sorted by total deviation ascending. The top entry as of launch: 0.89px. Close. Not close enough. Not even in the same universe as close enough.
Prize Category
Best Ode to Larry Masinter (HTTP 418 is front and center) and Community Favorite.
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