A simple, configurable Sass library for typography with perfect vertical rhythm.

Check out the demo

Shevy is a Sass library, and thus requires Sass to be installed on your machine and and some means of compiling Sass down to CSS. I leave the details of that setup to you.

One way to add Shevy to your project is to copy from source. If you want to add this to a project, copy the core/ directory into the appropriate location in your app.

$ cp -R core/ path/to/your/project

Then @import the _shevy.scss file into your project.

@import 'core/shevy';

Be sure to place this before any call to Shevy mixins and functions so that the Sass compiles without error.

You can install Shevy as an NPM module with:

npm install --save shevy

Once installed, you can proceed to include the core/_shevy.scss file in your project. It will likely be nested a directory or so deeper than directly copying from source, so be sure you get your path correct. Something like this:

@import '../../node_modules/shevy/core/shevy';

At this time (October 2016), I have not attempted to use Shevy with any JS-to-CSS configuration such as requiring it in a Webpack module. Thus, I have no recommendations for how to use it in that way... yet.

You can install Shevy as a Bower component:

bower install --save shevy

Similar to the NPM installation, this will install the project in another directory, so be sure to get your path correct when trying to import it.

@import '../../bower_components/shevy/core/shevy';

If you are using Ruby on Rails and would like to add Shevy to your project, you're in luck. Shevy is also a Ruby Gem. In your Gemfile add:

gem 'shevy'

Then run:

$ bundle install

Once the gem is installed, add Shevy to your project by adding:

@import 'shevy';

Once again, be sure to place this before any call to Shevy mixins or functions so that the Sass compiles without error.

Shevy comes packaged with default settings. So the simplest usage of Shevy is to call a few mixins.

@include headings;
@include body;
@include content;

This will output styles for all headings (h1 to h6), several content tags (p, ol, ul, and pre), and set font-size and line-height for the body tag. However, you may find that the default settings don't suit your project. Shevy allows you to configure settings globally and/or at the component level. Here's how:

Shevy mixins take a Sass map as one of the arguments. The default map is the $shevy map ($shevy is always defined, even if you don't define your own). Thus, to make global changes to your configuration, simply define your own $shevy map to override the default settings. Like so:

$shevy: (
  base-font-size: 14px,
  base-line-height: 1.5,
  base-font-scale: (2.5, 2.1, 1.8, 1.5, 1.25, 1),
  margin-bottom: true,
  proximity: false,
  proximity-factor: .85
);

Then, @include the headings, body, and content mixins in your code

@include headings;
@include body;
@include content;

Now marvel at your beautiful typography. Assuming you've put something on the page. You have put something on the page, haven't you?

You can also pass a custom map into the headings and paragraph mixin. This should enable you to make custom typography per module or responsive typography per breakpoint.

Define a new Shevy map:

$shevy-small: (
  base-font-size: 12px,
  base-line-height: 1.3,
  base-font-scale: (2, 1.8, 1.6, 1.4, 1.2, 1)
);

Then call the any of the mixins, passing your new settings map as an argument:

.my_component {
  @include headings($shevy-small);
  @include content($shevy-small);
}

$shevy: (
    base-font-size: 1em,
    base-line-height: 1.5,
    base-font-scale: (3, 2.5, 2, 1.5, 1.25, 1),
    margin-bottom: true,
    proximity: false,
    proximity-factor: .85
);

The base-font-size key is intended to be the standard font-size for the project. font-scale multiplies its value against the base-font-size.

The base-line-height is the standard line-height. If this is set in pixels, this will be the base-spacing value for Shevy. If it is provided as a factor, such as 1.5, it will be multiplied by the base-font-size to generate the base-spacing value.

This is a Sass list of factors to multiply by the base-font-size to generate the font-sizes for headings and paragraphs (if a paragraph-scale is not provided).

By default, margin bottoms are added to all typography to maintain the vertical rhythm. However, you may wish to remove these. In that case, setting margin-bottom: false in your map will set the margin-bottom property to 0 for each element.

In design, there is a phenomenon known as the proximity effect where our minds group things together that are close in spatial relation. Turning on proximity will enable you to apply a proximity factor to the margin-bottoms and base-spacing outputs, in effect, drawing content closer together. You might find this more aesthetically pleasing than strictly following the baseline.

Proximity factor is a factor with which to adjust the base spacing of your typography without affecting the line-height spacing. This value will be multiplied against the calculated base-spacing value, if proximity is set to true in your settings map.

There are several public functions available to the developer to use as they please. Here is a list of them:

• base-font-size(), with alias bsf()
• base-font-unit(), with alias bfu()
• base-line-height(), with alias blh()
• line-height-spacing(), with alias lhs()
• base-spacing(), with alias bs()
• settings()

base-font-size() will return the base-font-size setting in the $shevy map, or the map passed to the function as an argument.

base-font-unit() will determine whether the measurements have been defined in px, em, or rem and return the correct unit type. A map can be passed to the function as an argument.

base-line-height() will return the base-line-height setting in the $shevy map, or the map passed to the function as an argument.

line-height-spacing() calculates the line-height spacing of the vertical rhythm by multiplying the base font size by the base line-height. A factor may be passed to the argument to return multiples or dividends of the line-height spacing.

base-spacing() calculates the base spacing of the vertical rhythm by multiplying the base font size by the base line-height, with the additional math to handle proximity, thus differentiating it from the line-height-spacing() function. A factor may be passed to the argument to return multiples or dividends of the base-spacing.

Example:

.button {
  padding: bs(.5) bs(2);
}

A map of settings can be passed as the second argument to adjust the output.

settings() is a function utilized by Shevy to merge a map with the $shevy-defaults map. This ensures that the current map has all the settings it should. The user can use this to create new maps on the fly if they desire, though there isn't much of a purpose for that just yet.

Currently, Shevy supports px, em, and rem usage. Additional support for other measurement units may be added in the future.

The MIT License (MIT)

Copyright (c) 2016 Kyle Shevlin

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.