It is something that not everyone can understand, although there is no point of having HTML without CSS. CSS initially had only 50 styling options but even that was enough for the time. Now the time has changed and it is essential to have more customizable options. Although, the great news is that the level-4 of CSS has dropped. Therefore, if you wish to know a little something about CSS and its recent level read down our article below.

What is Cascading Style Sheet(CSS)?

Cascading Style Sheet is used for presentation purposes of all HTML elements on a webpage. It is among the holy trinity of UI development while the other two are namely HTML and Javascript. 

The style sheet language is used to create clean layout giving personal customisations to things like fonts and colors. A web page basically looks like a bunch of text without its inclusion. By using CSS, we are making our content more accessible and clean where each of the elements can be distinguished from each other with ease. It also provides way more control over the presentation of your website and use a single attribute on multiple elements using a single CSS tag.

This makes the styling of similar markup pages highly customisable. It in fact has separate rules for designing the mobile web page. The specification of the style sheet language is maintained by the World Wide Consortium(W3C). It is also among the maker of this particular language. The language is entirely free and W3C maintains the entire CSS validation service for the CSS documentation.

Importance of CSS in UI Development

Before CSS came into existence each of the webpages on the internet were designed using HTML markup language. This basically has limitation as one has to go to each and every element to start customisation. Also, the layout on the websites were not impressive enough and didn’t stand out from the rest of the web pages on the internet. 

There are various aspects of a web page design.Those aspects can be named as fonts, background styles, borders, element alignment, and most importantly sizes. Before CSS, there were issues where it was not possible to provide a similar style to similar type of elements. For instance, the h1, h2, and h3 tags. 

You wish to create a webpage and you decided to have a different font and color for the three given tags. Initially, one has to go through all the tags and change their color one by one. Although using CSS, it could be done more efficiently. All one has to do is to create a CSS file whether externally or make the changes in the style tag that can be declared at the top of the header. That would have applied all the changes you wanted with the tags.

For example:


h1 {

Color: red;


h2, h3 {

Color: black;



This will make the changes that you wanted with all those tags. Infact, the CSS properties can even be applied using a custom class. Although that is the lesson for advanced usage.

History of Cascading Style Sheet(CSS)

The first person to propose the use of CSS was Hakon Wium Lie. It was the collaboration of the duo Hakon and Tim Berners-Lee along with World Wide Web Consortium that made possible the release of the language on December 17, 1996.

CSS definitely had some advantage over the existing style sheet systems like DSSL and FOSI. With CSS, one can easily make changes to a couple of elements using the cascading style. Over time, the HTML grew and it required more stylistic changes to the webpages. CSS became popular because it was capable of delivering that required by UI developers. There have been definitive difficulties in adopting the system and making it mainstream. Although, for now it has become a crucial part of UI design without many of the times people and developers noticing it.

Different Version of Cascading Style Sheet(CSS)


This was the first iteration of the style sheet language. It came with its own set of capabilities that were great for the time. Below are some of the capabilities that the first iteration offered.

  • Customisation of font properties like typeface and emphasis.
  • Easy alignment of elements such as font, table, images etc.
  • Capability to change the color of the background, text, and many other elements.
  • Alignment of different types of elements like fonts, text, images etc.
  • Attributes like Margin, border, padding, and positioning of most elements.

There are a variety of other properties that CSS1 had for the user to offer.


The second iteration of the style sheet language in the year 1998 in the month of May. This one was obviously the better version of CSS1. It gave the developers capabilities like absolute, relative, and fixed positioning. It also gave the developers capabilities like z-index, inclusion of media types, aural style sheets etc. There was also bidirectional text and different properties for fonts.

There was another draft of CSS2.1 which was made with the intention of clearing out all the errors in the base version. A CSS2.2 version was also proposed although the work of it was kept on low priority.


The earliest draft of the first version of CSS3 was dropped in the year 1999. It brought along with itself the concept of “modules”. The intention behind creating the modules was to expand the capabilities of the previous version. Also, this one was added new capabilities to the module.


This is the latest version of the cascading style sheet that has been dropped. This version of CSS has been divided into various “level 4” modules. This is the reason there is no single integrated specification for the CSS4.

This iteration of the language has been developed on top of the previous levels. The level 4 attributes of the language comes with features like Image values, Backgrounds & Borders, and selectors. There are other really new and great modules that gives you entirely different capabilities for instance Flexbox.

The latest document has been dropped in the year 2018 starting from 2007.

Difference between CSS3 and CSS4

If we speak up with an open mind then the fact of the matter is that there really isn’t any CSS3 or CSS4. After the CSS2.1 got iteration once again and came up with new features both of the lateral entries were called such by the community. Also, there is no as such difference CSS3 or CSS4. 

With the modules approach of CSS3, the makers of the language wanted to make the UI developers more independent. That led to the creation of modules where the developer can work independently with each feature. 

This gave makers the advantage of updating the language as per their choice. Since all of the features were divided with modules then for example the makers could independently work on improving the module for font style. This gave advantage as now the makers could actually offer things that were more aligned as per the needs of the current scenario.

Therefore, in reality there is no CSS3 or CSS4. Infact, it would be accurate to call them level-3 or level-4. Although even that is purely with context to the degree by which the elements that were used in the CSS1 have been updated. For instance, Flexbox was never a thing until the CSS2.1. Therefore, when the feature was finally added what people say CSS3 then Flexbox was actually on level-1 and it being updated to level-2.

Advantages of Using CSS4

The major advantage that the UI developers are having by using the CSS4 iteration or level-4 CSS is in the case of selectors. They are not new and have been in use since the first iteration. Although, they get you more control and the ease of use has also increased from previously. Therefore, to know more about the greater advantage they are bringing on the table read down below:

Logical Combinators: There are basically two logical combinators that we will be talking about i.e :matches and :not. The “:matches” lets you define different definitions for single tag and allow you to use it all in one go. For example:

ul.features li a:matches(:link, :hover, :visited, :focus) {

   color: red;


Talking about the “:not” combinator this serves the purpose of pseudo negation can be used to apply to apply on multiple parameters just like “:match”.

Location Pseudo Classes: The two combinators that will be talked about in this section will be “:Any-Link” and “:Local-Link”. By using  “.Any-Link” combinator, the developer is making sure that all the elements of similar type will share similar attributes. For example:

H1:any-link {

Color: red;


The combinator will be the “:local-link”. This one will be making changes to all the local elements within a parenthesis. It is quite useful and very cool to use this feature since it gives you utmost control on the elements.

Time-Dimensional Pseudo Classes: This one also inscribes a couple of great selectors that can make your easy. It is great if you need selector for screen reader. The changes that will be made by the selector would be time dependent. For instance, if you want the color or h1 tag or anchor tag to change after a while then this type of selector can be easily used.

UI State Pseudo Classes: These can be used during the time when the state of the UI element is indeterminate. These selectors will allow the user to get the default state and react & respond accordingly.

Tree-Structured Pseudo Classes: This type of pseudo selectors helps you to pinpoint the element on which you wish to make changes. It is a great tool if mixed with the “:match” selector. Also, these give you the capability of customization at each nth element inside a tree.

Grid Structural Pseudo Classes: This one gets you some great selectors for the table that are used for the web pages. These can give you much control over the rows and columns. Some of the best selectors to use in this segment would be the :column, :nth-column, nth-last-column etc.

Parent Selectors: By far the most important selector that is provided along with level-4 package. This allows for you to easily style your elements at every parent node other than all the default places. There are some really great selectors in this category like .active, .StyleSwitcher etc.

Limitations of CSS4

The level-4 of the CSS is still tender, therefore, the limitations of the language can’t be estimated properly. Although, the moment we have sound ideas about it, we will be updating all that can be expected from the next iteration.

Top Lightweight Mobile CSS Frameworks


About: This is one of the most popular Lightweight Mobile CSS frameworks that are out there. It has a decent community of its own whenever it comes to web development. It can turn out to be a great tool if you are thinking of developing using HTML, CSS, and JS. This framework enables you to create responsive web pages. Also, it is really easy to implement grid using the framework.


  • The toolkit is open-source.
  • Capable of creating responsive web pages with ease.
  • Really fast for the creation of prototype.
  • Capable of making entire application using SASS and mixins.
  • Offers great responsive grid, prebuilt components, great plugins from JQuery.



About: Another really great lightweight Mobile CSS Frameworks that can be used for the development of web pages. It is modernized framework that is really to implement and offers you responsive design. The entire file of the framework is as light as 10KB and comes in a gzipped file. The entire responsive design of the framework is based on Flexbox. Also, it has so many great features that it will be a great help in case of developing web pages. 


  • Modernized CSS framework.
  • Offers responsive layout based on Flexbox.
  • Offers the user pure CSS components.
  • Provide basic styling for typography and elements.
  • Offers utilities for consistent coding and designing.


3.Semantic UI

About: Yet another really great lightweight mobile CSS framework that can make you some awesome looking web pages. It is really easy to use classes in this particular framework. Most of the syntax that is used in the Framework comprises of classes that use names from nouns/modifier. With this one can actually whatever he/she wishes to. The reason is simple, the framework offers so many features and elements which means that they haven’t left any stone unturned.


  • Get the benefit identical to BEM and SMACSS.
  • Javascript used in the Framework is quite intuitive.
  • It is very easy to debug because of its performance logging feature.
  • Allows you to use the same code at different places with different theming.
  • About 3000+ theming variables, 50+ UI components, and 5000+ commits.
  • Get a variety of responsive grid types.
  • Responsive sizing is very easy because of the em based build.
  • Can integrate with libraries like React, Angular, Meteor, Ember etc.



About: If you like minimalism then this probably is the framework of your choice. It is only sized at 2kb and is a great way to shell out great styles for a clean interface. The framework has been designed keeping the productivity in mind. There are the limited number of essential properties that is offered by the framework. This makes the code quite clean and makes it a great lightweight mobile CSS framework.


  • Get new units for Typography.
  • Comes with block quotes which can be intended for another purpose.
  • Simple layouts for buttons offered in three different styles.
  • Other than ul and ol, it also has dl(description list).
  • Offers proper formatting for tables.
  • Comes with functional classes to improve efficiency.


5.Picnic CSS

About: It is a great and beautiful framework to start working on your projects. The framework is quite lightweight not exceeding the limit of 10kb for the complete set. It is another really great lightweight mobile CSS framework that many of the UI developers prefer to use. The documentation for the framework is available online and it has great support from Github. If you haven’t tried then you can surely pick it up to soothe your work.


  • The framework entirely modular so can be used with ease.
  • Offers you all the native elements from HTML.
  • Easy to integrate with anything using bower.
  • Pretty extensive since it is written in SCSS.
  • Get multiple CSS transition.
  • The lightweight architecture makes it ideal for mobile devices.
  • It is open-source.



About: Bulma is among the popular framework that is designed purely for the ease of UI developers. Bulma is completely open-source and offers some really great extensive features to get your work in line. The framework is based on Flexbox thus provides great responsive design. As it can be seen in the image, the framework is being used by over 200,000 developers making it the best lightweight mobile CSS framework out there. It is pretty and can be easily recommended to anyone for use. Bulma for now is being used by some of the best organisations like DevSquad, Usave, tooltwist, Bid Papers, Paper Leaf etc.


  • Mobile designs are completely responsive.
  • It is open-source so comes with no extra cost.
  • Adding grid is easy as a breeze.
  • It is modular in nature.
  • Easy to learn and has a great community.
  • It doesn’t require the use of Javascript.



About: MaterializeCSS is another really great framework based on material design. The framework can help you make some really great web pages. With Materialize, the development of any UI project happens efficiently and fast. It has been integrated with a variety of custom components, great animations, and transitions. The framework have been made with the intent of providing ease to the user making it the best lightweight mobile CSS framework for UI development. Also, the user has access to the entire documentation which makes the work pretty easy.


  • It is offered with both minified and unminified CSS and Javascript files.
  • It is also offered with SASS.
  • The version gets you the source SCSS file.
  • Gets you visual cues to learn faster.
  • All the elements like grids, typography, color, and imagery have been made better &  beautiful.



About: Base is yet another really solid framework, if you wish to develop in CSS. This is a great lightweight Mobile CSS framework. With this framework, the user can focus more on creating projects than spending time overriding styles. There are a variety of templates that are associated with this framework. There are a plethora of applications that are associated with the framework. Therefore, there is no doubt that one can easily recommend this one to any UI developer.


  • The framework has been on top of Normalize.CSS.
  • It works consistently among all the browsers.
  • All the modules developed are individual.
  • Easily automate your workflow using a webpack config.



About: This one actually follows google’s guidelines for material design. This framework has been made from scratch so that it is fast, small, and quiet developer friendly. There isn’t a doubt that this one is among the top lightweight mobile CSS framework out there. The ultimate goal of its makers was to create a framework that’ll work great for the UI developers. This one is quite great and comes with a variety of different features.


  • The payload size is small.
  • It comes with no external independence.
  • Connects automatically to new DOM nodes.
  • Supports cross-platform development.
  • Can be customized to an extent.
  • Asynchronous loading of Javascript libraries.
  • CSS namesake can be used to separate between frameworks and app markup.


10.Mustard UI

About: The framework is pretty easy to use. This one can be integrated with your project in a couple of ways. It is so easy that all you have to do is integrate the zip file or just use npm. Although, this one doesn’t require anything like normalize.css. It may be the last entry but surely is the best lightweight mobile CSS framework. It offers a variety of options that can actually ease your development.


  • It is completely open-source.
  • With this one can start with the essential building blocks.
  • There are a variety of Grid structure offered alongside.
  • Get a variety of typography with a base font size of 16px.
  • Different styles of button that can be used for development.
  • Get different types of pricing tables.
  • Multiple panels offered for the ease.


So this was our basic guide to CSS4 and the ease it might bring to the UI developers. It is of no doubt that CSS is the most important part of UI development. Although in case if you need an app company to develop a website for you then we can help you. In order to send us a business enquiry mail us at [email protected]. We have written an article over iOS 13 vs Android 10, therefore, to read it click on the link provided. We hope this article may have been of some help to you. Also, thank you for reading the article until the end. 

Sudeep Bhatnagar
Co-founder & Director of Business
Sudeep Bhatnagar

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