Game Boy Implementation

— 7 minute read

Background permalink

Recently I was on Dribble and I found this design by Rogie. I had read somewhere on the web that implementing designs from Dribble was a good way to sharpen CSS skills. So I figured, why not, I would have at it.

Finished Product permalink

Video permalink

Demo permalink

See the Pen Gameboi by Martín E (@martineizayaga) on CodePen.

How I Made It permalink

I thought that this was going to be very straightforward, but I was surprised at the number of challenges that came my way and how much I would learn.

Stacked Box Shadows permalink

The first challenge was trying to replicate the shadow. It wasn't a challenge at all because of Sara L. Fossheim's blog post on box-shadows. I had no idea that one could stack several box-shadows.

#gameboy {
15px 0px 0 0px black,
20px 0px 0 0px white,
32px 0px 0 0px black;

To make the shadow horizontally interactive, I wrote a function that changed the box-shadow of #gameboy every time the slider value changed.

function changeShadow(value) { = `
${15 * value / 100}px 0px 0 0px black,
${20 * value / 100}px 0px 0 0px white,
${32 * value / 100}px 0px 0 0px black

The value goes from -100 to 100, so the h-offset so the first box-shadow, for instance, would go from -15 to 15. Perfect 😎.

The box-shadows for the other parts of the Game Boy (like the buttons) were manipulated in pretty much the same way.

The Inner Face Illusion permalink

One of the disadvantages of using box-shadow was that I could not figure out a way to have the face be a part of the shadow (if you know, let me know pls!) So, I had to figure out how to give the illusion of there being a box cutout where the screen is.

I started by making a black div with the face on it, but then it covered the outer screen's bottom right border radius. After much Googling, I found out about overflow: hidden. This attribute value clips the overflow content, making it invisible.

In order to have it shift left and right with the horizontal slider, I added a line to the changeShadow function. = `${value/10}px`;

Since the black screen had an absolute positioning, a negative left positioning would shift it out of the parent screen. The value goes from -100 to 100, so the left property would go from -10 to 10.

Advanced Border Styling permalink

I had to round the bottom right corner of the Game Boy, but border-radius: value didn't suffice. I found out that one can specify the length of the curve on every edge of the border. Here's what I had for #gameboy.

#gameboy {
border-top-left-radius: 5% 3%;
border-top-right-radius: 5% 3%;
border-bottom-right-radius: 25% 15%;
border-bottom-left-radius: 5% 3%;

This would mean, for instance, that the first value of border-bottom-right-radius is for the bottom border and the second value is for the right border.

I used this trick to make the mouth.

.mouth {
border-radius: 50% 50% 50% 50% / 0% 0% 70% 70%;

This is shorthand for the following.

border-top-left-radius: 50% 0%;
border-top-right-radius: 50% 0%;
border-bottom-right-radius: 50% 70%;
border-bottom-left-radius: 50% 70%;

Styling the Sliders permalink

The last big challenge of this implementation was prettying up the sliders. The style that Rogie chose was similar to the shadow of the Game Boy, so I couldn't just leave the default sliding styles. Little did I know of how picky each browser would be with slider styles. I found a great CSS-Tricks article that really helped me out.

Safari and Firefox have their own CSS selectors for the track (the sliding track) and the thumb (what you click to drag to a value.) There's not much more than I can say except to recommend the CSS-Tricks article.

I did however find out that an <input> with type="range" and orient="vertical" won't have css styles in Webkit (Chrome, Safari, Opera.) So I had to rotate the input instead. I was kind of sad about that though. I like adding new HTML attributes if they're helpful :(.

#verticalRange {
grid-area: vslider;
-webkit-appearance: none;
transform: rotate(-90deg);

In order to stay true to the design, I had the thumb slider have a box-shadow and a border the same width as the rest of the design. Here's what I had for WebKit.

input[type=range]::-webkit-slider-thumb {
-webkit-appearance: none;
border: var(--border-width) solid black;
height: 20px;
width: 20px;
border-radius: 50%;
background-color: white;
cursor: pointer;
box-shadow: 0px 2px 0 0px black;
box-sizing: border-box;

What I learned permalink

  • box-shadow's can be stacked.
  • overflow: hidden clips the content that overflows.
  • Browsers have different pseudo selectors for input sliders and thumbs.
  • WebKit input sliders won't show styling if it has orientation="vertical". You should probably rotate the slider instead.
  • border-radius can have more than one value and has a handy shorthand.
  • Implementing designs from Dribble is kinda fun. :)