One Thing Well

Squeezeit

A command line tool for minifying Javascript and CSS, written in Python.

Via HN.

Bear CSS

Bear CSS is a handy little tool for web designers. It generates a CSS template containing all the HTML elements, classes & IDs defined in your markup.

Glue

Glue is a simple command line tool to generate CSS sprites.

Turns a directory of image files into a sprite with accompanying CSS.

Via pb

Bootstrap Generator

Kick-start your Twitter Bootstrap project the way you want. Simply alter the options below and click “Generate” to get your compiled Bootstrap CSS file.

Gradient makes it easy to generate CSS3 background gradients. The retro sci-fi UI might not be to everyone’s taste, but in practice it’s simple to use, fast and reliable.

For those unfamiliar with CSS and wondering why you’d need a dedicated app for something as seemingly simple as a gradient, here’s the code required to get the grey-to-black fade shown above working across all the popular browsers:

background-color: #dbcfdb;
background-image: -webkit-gradient(linear, left center, right center, to(rgb(219, 207, 219)), from(rgb(61, 61, 60)));
background-image: -webkit-linear-gradient(left, rgb(219, 207, 219), rgb(61, 61, 60));
background-image: -moz-linear-gradient(left, rgb(219, 207, 219), rgb(61, 61, 60));
background-image: -o-linear-gradient(left, rgb(219, 207, 219), rgb(61, 61, 60));
background-image: -ms-linear-gradient(left, rgb(219, 207, 219), rgb(61, 61, 60));
background-image: linear-gradient(left, rgb(219, 207, 219), rgb(61, 61, 60));
filter: progid:DXImageTransform.Microsoft.gradient(startColorStr='#dbcfdb', EndColorStr='#3d3d3c');

Xeo CSS

Xeo CSS is a fully Web-based styling tool for web developers. Forget about CSS coding. Style your website with ease - every minute detail of it - using this unique Web-app.

I’m not quite sure why you’d use a web-based CSS editor, but as a proof of concept it’s impressive.

WebPutty

WebPutty gives you a syntax-highlighting CSS editor you can use from anywhere, the power of SCSS and Compass, a side-by-side preview pane, and instant publishing with minification, compression, and automatic cache control. Get started with just a pair of tags in your website’s template and WebPutty will host and serve your published CSS minified and gzipped for super speed.

Ideal for hosted sites like Tumblr, I’d imagine. It’s ‘free for early adopters’ too.

CSS3 Please!

An interactive cross-browser CSS3 generator: a quick and easy way to ensure your fancy modern styling works everywhere, without having to remember how to make, eg., a linear gradient work in Opera and IE 7.

Smaller

Smaller is a Graphic User Interface for YUI Compressor on the Mac. It helps you batch minify CSS and JavaScript files with a nice drag and drop interface. It’s a perfect tool for we Web designers and developers who are not big fans of command line.

holmes.css

Holmes is stand-alone diagnostic CSS stylesheet that can highlight potentially invalid, inaccessible or erroneous HTML(5) markup by adding one class.

Juicer

A command line tool for JavaScript and CSS developers.

Merge CSS files, and convert referenced images to data URIs; merge, minify and compress JS files.

Less

The CSS framework now has ~~less~~ fewer features and lets you easily design a responsive layout that works well on desktop, tablet and mobile devices.