This is an experiment that creates social media icons using CSS and semantic HTML. It uses progressive enhancement to turn an unordered list of text links into a set of icons without the use of images or JavaScript.

Demo: Pure CSS social media icons

Support: Firefox 3.5+, Safari 4+, Chrome 4+, Opera 10+, IE8+.

CSS social media icons

The image below shows you the final appearance in modern browsers.

This experiment starts with a simple list of links, with each link using meaningful text, and then progressively styles each link to take on the appearance of the relevant social media icon. As a result, there should be support for screenreaders or users with CSS disabled.

I’ve also included basic text in the title attribute of each link to provide information for users who may not be familiar with what service a specific icon represents.

This is an experiment that uses CSS 2.1 and CSS3 that is not supported by Internet Explorer 6 and 7, therefore, you shouldn’t expect it to work in those browsers. CSS is not necessarily the most appropriate tool for this kind of thing either.

Example code

The technique I’ve used is much the same as the one used for the Pure CSS speech bubbles.

The HTML is just a basic unordered list of links to various social networking websites or services.

<ul>
   <li class="facebook"><a href="#non" title="Share on Facebook">Facebook</a></li>
   <li class="twitter"><a href="#non" title="Share on Twitter">Twitter</a></li>
   <li class="rss"><a href="#non" title="Subscribe to the RSS feed">RSS</a></li>
   <li class="flickr"><a href="#non" title="Share on Flickr">Flickr</a></li>
   <li class="delicious"><a href="#non" title="Bookmark on Delicious">Delicious</a></li>
   <li class="linkedin"><a href="#non" title="Share on LinkedIn">LinkedIn</a></li>
   <li class="google"><a href="#non" title="Bookmark with Google">Google</a></li>
   <li class="orkut"><a href="#non" title="Share on Orkut">Orkut</a></li>
   <li class="technorati"><a href="#non" title="Add to Technorati">Technorati</a></li>
   <li class="netvibes"><a href="#non" title="Add to NetVibes">NetVibes</a></li>
</ul>

I’ve applied some general styles to the elements that make up this list.

ul {
   list-style:none;
   padding:0;
   margin:0;
   overflow:hidden;
   font:0.875em/1 Arial, sans-serif;
}

ul li {
   float:left;
   width:66px;
   height:66px;
   margin:20px 20px 0 0;
}

ul li a {
   display:block;
   width:64px;
   height:64px;
   overflow:hidden;
   border:1px solid transparent;
   line-height:64px;
   text-decoration:none;
   /* css3 */
   text-shadow:0 -1px 0 rgba(0,0,0,0.5);
   -moz-border-radius:5px;
   -webkit-border-radius:5px;
   border-radius:5px; /* standards version last */
}

ul li a:hover,
ul li a:focus,
ul li a:active {
   opacity:0.8;
   border-color:#000;
}

Each icon uses it’s own set of styles. This is the CSS that created the RSS icon.

.rss a {
   position:relative;
   width:60px;
   padding:0 2px;
   border-color:#ea6635;
   text-transform:lowercase;
   text-indent:-186px;
   font-size:64px;
   font-weight:bold;
   color:#fff;
   background:#e36443;

   /* css3 */
   -moz-box-shadow:0 0 4px rgba(0,0,0,0.4);
   -webkit-box-shadow:0 0 4px rgba(0,0,0,0.4);
   box-shadow:0 0 4px rgba(0,0,0,0.4);
   background:-webkit-gradient(linear, left top, left bottom, from(#f19242), to(#e36443));
   background:-moz-linear-gradient(top, #f19242, #e36443);
   background:linear-gradient(top, #f19242, #e36443);
}

.rss a:before,
.rss a:after {
   content:"";
   position:absolute;
   bottom:10px;
   left:10px;
}

/* create circle */
.rss a:before {
   width:12px;
   height:12px;
   background:#fff;
   /* css3 */
   -moz-border-radius:12px;
   -webkit-border-radius:12px;
   border-radius:12px;
}

/* create the two arcs */
.rss a:after {
   width:22px;
   height:22px;
   border-style:double;
   border-width:24px 24px 0 0;
   border-color:#fff;
   /* css3 */
   -moz-border-radius:0 50px 0 0;
   -webkit-border-radius:0 50px 0 0;
   border-radius:0 50px 0 0;
}

Acknowledgements

This post was inspired by an experiment on insicdesigns that producing a few social media icons using CSS.

Create a simple CSS folded-corner effect without images or extra markup. It works well in all modern browsers and is best suited to designs with simple colour backgrounds.

Demo: Pure CSS folded-corner effect

Known support: Firefox 3.5+, Chrome 4+, Safari 4+, Opera 10+, IE 8+

This post is going to expand on the technique used to create the folded-corner effect that is part of the demo page for Multiple Backgrounds and Borders with CSS 2.1. As a starting point it will look to recreate the appearance of the note style used on the Yiibu‘s fantastic web site. Where Yiibu uses images, this will use pseudo-elements.

Nothing complicated. Any element will do and there’s no need for extra markup. It’s just a simple coloured box to start with. Browsers with no support for pseudo-elements, such as IE6 and IE7, will only be capable of displaying this.

Adding position:relative makes it possible to absolutely position the pseudo-element.

.note {
  position: relative;
  width: 30%;
  padding: 1em 1.5em;
  margin: 2em auto;
  color: #fff;
  background: #97C02F;
}

The folded-corner

The folded-corner is created from a pseudo-element that is positioned in the top corner of the box. The pseudo-element has no width or height but is given a thick border. Varying the size of the border will vary the size of the folded-corner.

In this example, the top and right borders are set to colours that match the background colour of the box’s parent. The left and bottom border are then given a slightly darker or lighter shade of the box’s background colour.

.note:before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  border-width: 0 16px 16px 0;
  border-style: solid;
  border-color: #658E15 #fff;
}

This is all that’s needed to create a simple folded-corner effect like that found on Yiibu.

Firefox 3.0 doesn’t allow for the positioning of pseudo-elements. You can throw in a couple of extra styles to help tidy things up in that browser.

.note:before {
  ...
  display: block;
  width: 0;
}

Adding a subtle shadow

The appearance of a fold can be slightly enhanced by adding a box-shadow (for browsers that support it) to the pseudo-element. Setting overflow:hidden on the note itself will help hide parts of the shadow that would disrupt the folded-corner effect.

.note:before {
  ...
  -webkit-box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px 1px 1px rgba(0,0,0,0.2);
  -moz-box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px 1px 1px rgba(0,0,0,0.2);
  box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px 1px 1px rgba(0,0,0,0.2);
}

Rounded corners

It’s also relatively simple to make this work with rounded corners if desired. Unfortunately, every modern browser has some form of border-radius bug – including those using the non-prefixed property – which means a slight work around is needed.

Webkit browsers are the only browsers that can come anywhere close to rounding the corner of the pseudo-element if it only has 2 borders. Opera 11 and Firefox 3.6 make a mess of it. Opera 11 makes the biggest mess.

Using 4 borders avoids the problems in Opera 11 and Firefox 3.6. But it will trigger a bug in Safari 5 that leaves the diagonal looking a little jaggy. We can get around this problem by setting at least one border colour to be transparent.

When a background colour is applied to the pseudo-element it will show through the transparent border. Ideally, this approach would form the basis of the entire effect because we could reduce the amount of code needed. But Opera 11 will not show the background colour through the transparent borders unless a border-radius has been set.

.note-rounded:before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  border-width: 8px;
  border-color: #fff #fff transparent transparent;
  background: #658E15;
  -moz-border-radius: 0 0 0 5px;
  border-radius: 0 0 0 5px;
  display: block;
  width: 0;
}

The CSS file on the demo page has more comments on the work arounds. Every browser has its own peculiarities when it comes to using border-radius or borders on elements with no width or height. This is the merely simplest solution I’ve found to deal with those browser inconsistencies.

The final code

This is all the CSS needed to create a simple folded-corner effect, with a subtle shadow, from a single HTML element. To include a variant with rounded corners, the “note” object can be extended with the modifications described previously.

.note {
  position: relative;
  width: 30%;
  padding: 1em 1.5em;
  margin: 2em auto;
  color: #fff;
  background: #97C02F;
  overflow: hidden;
}

.note:before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  border-width: 0 16px 16px 0;
  border-style: solid;
  border-color: #fff #fff #658E15 #658E15;
  background: #658E15;
  -webkit-box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px 1px 1px rgba(0,0,0,0.2);
  -moz-box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px 1px 1px rgba(0,0,0,0.2);
  box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px 1px 1px rgba(0,0,0,0.2);
  /* Firefox 3.0 damage limitation */
  display: block; width: 0;
}

.note.rounded {
  -moz-border-radius: 5px 0 5px 5px;
  border-radius: 5px 0 5px 5px;
}

.note.rounded:before {
  border-width: 8px;
  border-color: #fff #fff transparent transparent;
  -moz-border-radius: 0 0 0 5px;
  border-radius: 0 0 0 5px;
}

The demo page shows the final effect, an example with rounded corners, and how different coloured notes are easy to create from this base.

This technique works less well when the element receiving the folded-corner effect is sitting on top of a background image rather than a simple background colour. However, the same limitation exists for image-based methods of creating this effect.

Twitter Lite uses Redux for state management and relies on code-splitting. However, Redux’s default API is not designed for applications that are incrementally-loaded during a user session.

This post describes how I added support for incrementally loading the Redux modules in Twitter Lite. It’s relatively straight-forward and proven in production over several years.

Redux modules

Redux modules comprise of a reducer, actions, action creators, and selectors. Organizing redux code into self-contained modules makes it possible to create APIs that don’t involve directly referencing the internal state of a reducer – this makes refactoring and testing a lot easier. (More about the concept of redux modules.)

Here’s an example of a small “redux module”.

// data/notifications/index.js

const initialState = [];
let notificationId = 0;

const createActionName = name => `app/notifications/${name}`;

// reducer
export default function reducer(state = initialState, action = {}) {
  switch (action.type) {
    case ADD_NOTIFICATION:
      return [...state, { ...action.payload, id: notificationId += 1 }];
    case REMOVE_NOTIFICATION:
      return state.slice(1);
    default:
      return state;
  }
}

// selectors
export const selectAllNotifications = state => state.notifications;
export const selectNextNotification = state => state.notifications[0];

// actions
export const ADD_NOTIFICATION = createActionName(ADD_NOTIFICATION);
export const REMOVE_NOTIFICATION = createActionName(REMOVE_NOTIFICATION);

// action creators
export const addNotification = payload => ({ payload, type: ADD_NOTIFICATION });
export const removeNotification = () => ({ type: REMOVE_NOTIFICATION });

This module can be used to add and select notifications. Here’s an example of how it can be used to provide props to a React component.

// components/NotificationView/connect.js

import { connect } from 'react-redux';
import { createStructuredSelector } from 'reselect';
import { removeNotification, selectNextNotification } from '../../data/notifications';

const mapStateToProps = createStructuredSelector({
  nextNotification: selectNextNotification
});
const mapDispatchToProps = { removeNotification };

export default connect(mapStateToProps, mapDispatchToProps);

// components/NotificationView/index.js

import connect from './connect';
export class NotificationView extends React.Component { /*...*/ }
export default connect(NotificationView);

This allows you to import specific modules that are responsible for modifying and querying specific parts of the overall state. This can be very useful when relying on code-splitting.

However, problems with this approach are evident once it comes to adding the reducer to a Redux store.

// data/createStore.js

import { combineReducers, createStore } from 'redux';
Import notifications from './notifications';

const initialState = /* from local storage or server */

const reducer = combineReducers({ notifications });
const store = createStore(reducer, initialState);

export default store;

You’ll notice that the notifications namespace is defined at the time the store is created, and not by the Redux module that defines the reducer. If the “notifications” reducer name is changed in createStore, all the selectors in the “notifications” Redux module no longer work. Worse, every Redux module needs to be imported in the createStore file before it can be added to the store’s reducer. This doesn’t scale and isn’t good for large apps that rely on code-splitting to incrementally load modules. A large app could have dozens of Redux modules, many of which are only used by a few components and unnecessary for initial render.

Both of these issues can be avoided by introducing a Redux reducer registry.

Redux reducer registry

The reducer registry enables Redux reducers to be added to the store’s reducer after the store has been created. This allows Redux modules to be loaded on-demand, without requiring all Redux modules to be bundled in the main chunk for the store to correctly initialize.

// data/reducerRegistry.js

export class ReducerRegistry {
  constructor() {
    this._emitChange = null;
    this._reducers = {};
  }

  getReducers() {
    return { ...this._reducers };
  }

  register(name, reducer) {
    this._reducers = { ...this._reducers, [name]: reducer };
    if (this._emitChange) {
      this._emitChange(this.getReducers());
    }
  }

  setChangeListener(listener) {
    this._emitChange = listener;
  }
}

const reducerRegistry = new ReducerRegistry();
export default reducerRegistry;

Each Redux module can now register itself and define its own reducer name.

// data/notifications/index.js

import reducerRegistry from '../reducerRegistry';

const initialState = [];
let notificationId = 0;

const reducerName = 'notifications';

const createActionName = name => `app/${reducerName}/${name}`;

// reducer
export default function reducer(state = initialState, action = {}) {
  switch (action.type) {
    case ADD_NOTIFICATION:
      return [...state, { ...action.payload, id: notificationId += 1 }];
    case REMOVE_NOTIFICATION:
      return state.slice(1);
    default:
      return state;
  }
}

reducerRegistry.register(reducerName, reducer);

// selectors
export const selectAllNotifications = state => state[reducerName];
export const selectNextNotification = state => state[reducerName][0];

// actions
export const ADD_NOTIFICATION = createActionName(ADD_NOTIFICATION);
export const REMOVE_NOTIFICATION = createActionName(REMOVE_NOTIFICATION);

// action creators
export const addNotification = payload => ({ payload, type: ADD_NOTIFICATION });
export const removeNotification = () => ({ type: REMOVE_NOTIFICATION });

Next, we need to replace the store’s combined reducer whenever a new reducer is registered (e.g., after loading an on-demand chunk). This is complicated slightly by the need to preserve initial state that may have been created by reducers that aren’t yet loaded on the client. By default, once an action is dispatched, Redux will throw away state that is not tied to a known reducer. To avoid that, reducer stubs are created to preserve the state.

// data/createStore.js

import { combineReducers, createStore } from 'redux';
import reducerRegistry from './reducerRegistry';

const initialState = /* from local storage or server */

// Preserve initial state for not-yet-loaded reducers
const combine = (reducers) => {
  const reducerNames = Object.keys(reducers);
  Object.keys(initialState).forEach(item => {
    if (reducerNames.indexOf(item) === -1) {
      reducers[item] = (state = null) => state;
    }
  });
  return combineReducers(reducers);
};

const reducer = combine(reducerRegistry.getReducers());
const store = createStore(reducer, initialState);

// Replace the store's reducer whenever a new reducer is registered.
reducerRegistry.setChangeListener(reducers => {
  store.replaceReducer(combine(reducers));
});

export default store;

Managing the Redux store’s reducer with a registry should help you better code-split your application and modularize your state management.

The Home Ministry had on Thursday allowed chariot construction with a condition that no religious congregation should take place around the Ratha Khala.

Two prominent medical experts — AIIMS director Dr Randeep Guleriya and Dr. Manish Suneja — flew into Ahmedabad on Friday following instructions from the Home Minister to guide local doctors

HDIL promoter is lodged in Arthur Road Central Jail

Court says Hemant Bhatt needs to be treated at a govt. hospital

With a view to prevent him from acting in any manner prejudicial to the maintenance of public order, Naeem Akhtar detention is being extended, an order said.

Court wants decision on levying costs for transport of migrant workers

This has been the highest spike in the number of cases in the State in a single day, taking the number of cases to 1,678

In his address, CM says lockdown cannot go on forever

The NCMC chaired by Cabinet Secretary Rajiv Gauba met on Friday to review the situation arising out of the gas leak

Mumbai civil and sessions court gives anticipatory bail to two others who are in quarantine

All returnees are taken to centres from buses and trains

Rupa Rani Bhuyan, assistant professor of Mangaldoi College, was held for “misbehaving” with the police and “obstructing” them from investigating cases against her

Drake, Matthew, author

Görög, Mihály, 1951-

Kreilkamp, Edgar

Greene, Jeffrey R., author

Klein, Bente

Russell, Doug

Brown, Paul C

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Schniederjans, Marc J., author

Schragenheim, Eli