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The module presents the concepts used in the CSS programming language.

Introduction

Cascading Style Sheets (abbreviated CSS) are used to describe how (X)HTML or XML text is to be presented. This module is currently a commented link list of important entry points for reading about CSS.

This module gives a simple example how a CSS style sheet works.

Content of this module

Css rules

A CSS file consists of statements which are either at-rules or rule sets (often just called rules). A rule set (rule) consists of a selector and a declaration block which contains one or more declarations (more see CSS 2.1 specification ). A declaration contains a property and a value (e.g. "color" and "green"), see example below. These rules describe how the formatting should take place.

Below are some sample rules. In the first part one or several selectors are given and in the second part there are one or more attribute-value pairs enclosed by curly brackets.

/* Sample rules */ h1, h2 {color: green}#box {width: 70%} .topic {color: red}

    Selector types

  • h1 and h2 are tag selectors
  • #box is a selector for an identification
  • .topic is a selector for a class

A series of tests for selectors.

Internal and external style sheets

A style sheet may reside in a separate file ( external style sheet ) or within an (X)HTML file ( internal style sheet ).

External style sheet

<head><link rel="stylesheet" type="text/css" media="screen, projection, handheld, print" href="css/general.css" /><link rel="stylesheet" type="text/css" media="print" href="css/ourPrintStyleSheet.css" /></head>

In the case of the code above taken from a HTML file we load a general style sheet for different kinds of output media called general.css and a specific one for printing ( ourPrintStyleSheet.css ). The style sheet for printing adds and overrides some rules to put the content onto paper.

Internal stylesheet (html)

<style type="text/css">h1 { color: green;}</style>

Internal stylesheet (xhtml)

<style type="text/css"><![CDATA[ h1 {color: green; }]]></style>

@import rule

The @import rule ( ref. ) allows you to import rules from another style sheet into your current one. For an example see ´web fonts´ below.

Reference

CSS 2.1 specification (implemented by most browsers); an index

All W3C CSS standards and drafts

The link above includes the documents commonly called CSS 3 which consists of different modules. They are implemented to various degrees in the current browsers.

Tutorial

w3.org: Starting with HTML and CSS (basic introduction)

Complete course with interactive exercises w3schools

Searching for the key words css cheat sheet provides helpful links if you have learned CSS in the past. This brings up for example this list which leads to 30 examples .

Layout with css

For doing layout with CSS the 'position' attribute and the box model are used. In the past this was difficult because the box model implemented by the Internet Explorer (IE) differed from the web standard and from the box model implemented by other browsers. In the meantime the Internet Explorer supports the standard W3C box model so using CSS in modern browsers is made easier as there needs not to be a 'switch' anymore for IE and the other browsers. CSS 3 introduces the box-sizing property which allows to set how the box size is calculated ( (External Link) ).

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Test collection. OpenStax CNX. Jul 20, 2012 Download for free at https://legacy.cnx.org/content/col11420/1.2
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