The core

The core of Stylite is the ability to express CSS rules using Reason syntax.

A selector is a string of a CSS selector. A declaration is a reason constuctor that corresponds to a css declaration e.g. BackgroundColor "red" or PaddingTop "10px".

A rule is a couple made of:

1. a list of selectors
2. a list of declarations

A mediaQuery is a couple made of:

1. optional media query
2. a list of rules

Here is an example of a rule and mediaQuery:

let my_rule = (["#button-1", ".big-rectangle"], [BackgroundColor("red"), PaddingTop("10px")]);
let my_media_query = (Some("screen and (max-width: 664px)"), [my_rules]);

We can convert a rule to a CSS statement with print_rule:

print(my_rule);
/*
"#button-1, .big-rectangle {
  background-color: red;
  padding-top: 10px;
}";
*/

And convert a mediaQuery to a CSS statement with print_media_query:

print(my_media_query);
/*
"@media screen and (max-width: 664px) {
  #button-1, .big-rectangle {
    background-color: red;
    padding-top: 10px;
  }
}";
*/

Integration in an application

In order to integrate Stylite rules in an application one has to:

1. Create a Stylite instance with Stylite.Make()
2. Register the rules into a class with register_rules
3. Apply the class to an element
4. Load all the class rules (this is done differently for client side and server side rendering (print_all_rules))

Register rules into a class

We can register

let wrap_image_cls =
  StyliteRe.Rules.(
    Stylite.register_rules(
      ~cls="wrap_image",
      ~declaration=[
        BorderRadius("30px"),
        Border("1px solid"),
        BorderColor("#19c0ff"),
        MarginRight("15px"),
        Cursor("pointer")
      ],
      ()
    )
  );

Pseudo selector and nested selector

open StyliteRe.Rules;

let image_cls = Stylite.register_rules(~cls="image", ~decl=[Margin("15px")]);

let wrap_image_cls =
  Stylite.register_rules(
    ~cls="wrap_image",
    ~rules=[
      (["&:hover > ." ++ image_cls], [Border("solid 1px red")]),
      (["& > ." ++ image_cls], [Border("solid 1px black")])
    ],
    ()
  );

let css = Stylite.print_all();

// Css is
// .image {
//   margin 15px;
// }
//
// .wrap_image:hover .image {
//   border: solid 1px red;
// }
//
// .wrap_image .image {
//   border: solid 1px black;
// }
//

Use media query

open StyliteRe.Rules;

let image_cls = Stylite.register_rules(~cls="image", ~decl=[Margin("15px")]);

let wrap_image_cls =
  Stylite.register_rules(
    ~cls="wrap_image",
    ~mediaQueries=[
      (None, [(["&"], [Color("blue")])]),
      (
        Some("screen and (max-width: 664px)"),
        [
          (["&:hover > ." ++ image_cls], [Border("solid 1px red")]),
          (["& > ." ++ image_cls], [Border("solid 1px black")]),
        ],
      ),
    ],
    (),
  );


let css = Stylite.print_all();

// Css is
// 
// .image {
//   margin 15px;
// }
//
// .wrap_image {
//   color: blue;
// } 
//
// @media screen and (max-width: 664px) {
//   .wrap_image:hover .image {
//     border: solid 1px red;
//   }
//
//   .wrap_image .image {
//     border: solid 1px black;
//   }
// }
//

Server side rendering

retrieve the CSS string with print_all and put it into a <style> element

Client side rendering

Once the first page of the app is created, inject the CSS into a tag and follow style changes with inject_in_tag_and_follow_changes.