nd manipulate the boxes that your content sits inside. Now it's
time to look at how to place your boxes in the right place in relation to the
viewport, and to each other. We have covered the necessary prerequisites so we
can now dive deep into CSS layout, looking at different display settings,
modern layout tools like flexbox, CSS grid, and positioning, and some of the
legacy techniques you might still want to know about.

[ Use CSS to solve common problems ](/en-US/docs/Learn/CSS/Howto)

    

This module provides links to sections of content explaining how to use CSS to
solve common problems when creating a web page.

##  Reference

  * [ CSS reference ](/en-US/docs/Web/CSS/Reference) : This exhaustive reference for seasoned Web developers describes every property and concept of CSS. 
  * CSS key concepts: 
    * The [ syntax and forms of the language ](/en-US/docs/Web/CSS/Syntax)
    * [ Specificity ](/en-US/docs/Web/CSS/Specificity) , [ inheritance ](/en-US/docs/Web/CSS/Inheritance) , and [ the Cascade ](/en-US/docs/Web/CSS/Cascade)
    * [ CSS units and values ](/en-US/docs/Web/CSS/CSS_Values_and_Units) and [ functional notations ](/en-US/docs/Web/CSS/CSS_Functions)
    * [ Box model ](/en-US/docs/Web/CSS/CSS_box_model/Introduction_to_the_CSS_box_model) and [ margin collapse ](/en-US/docs/Web/CSS/CSS_box_model/Mastering_margin_collapsing)
    * The [ containing block ](/en-US/docs/Web/CSS/Containing_block)
    * [ Stacking ](/en-US/docs/Web/CSS/CSS_positioned_layout/Understanding_z-index/Stacking_context) and [ block-formatting ](/en-US/docs/Web/CSS/CSS_display/Block_formatting_context) contexts 
    * [ Initial ](/en-US/docs/Web/CSS/initial_value) , [ computed ](/en-US/docs/Web/CSS/computed_value) , [ used ](/en-US/docs/Web/CSS/used_value) , and [ actual ](/en-US/docs/Web/CSS/actual_value) values 
    * [ CSS shorthand properties ](/en-US/docs/Web/CSS/Shorthand_properties)
    * [ CSS Flexible Box Layout ](/en-US/docs/Web/CSS/CSS_flexible_box_layout)
    * [ CSS Grid Layout ](/en-US/docs/Web/CSS/CSS_grid_layout)
    * [ CSS selectors ](/en-US/docs/Web/CSS/CSS_selectors)
    * [ Media queries ](/en-US/docs/Web/CSS/CSS_media_queries)
    * [ Animation ](/en-US/docs/Web/CSS/animation)

##  Cookbook

The [ CSS layout cookbook ](/en-US/docs/Web/CSS/Layout_cookbook) aims to bring
together recipes for common layout patterns, things you might need to
implement in your sites. In addition to providing code you can use as a
starting point in your projects, these recipes highlight the different ways
layout specifications can be used and the choices you can make as a developer.

##  Tools for CSS development

  * You can use the [ W3C CSS Validation Service ](https://jigsaw.w3.org/css-validator/) to check if your CSS is valid. This is an invaluable debugging tool. 
  * [ Firefox Developer Tools ](https://firefox-source-docs.mozilla.org/devtools-user/index.html) lets you view and edit a page's live CSS via the [ Inspector ](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/index.html) and [ Style Editor ](https://firefox-source-docs.mozilla.org/devtools-user/style_editor/index.html) tools. 
  * The [ Web Developer extension ](https://addons.mozilla.org/en-US/firefox/addon/web-developer/) for Firefox lets you track and edit live CSS on watched sites. 

##  Meta bugs

  * Firefox: [ Firefox bug 1323667 ](https://bugzil.la/1323667)

##  See also

  * [ CSS demos ](/en-US/docs/Web/Demos#css) : Get a creative boost by exploring examples of the latest CSS technologies in action. 
  * Web languages to which CSS is often applied: [ HTML ](/en-US/docs/Web/HTML) , [ SVG ](/en-US/docs/Web/SVG) , [ MathML ](/en-US/docs/Web/MathML) , [ XHTML ](/en-US/docs/Glossary/XHTML) , and [ XML ](/en-US/docs/Web/XML/XML_introduction) . 
  * [ Stack Overflow questions about CSS ](https://stackoverflow.com/questions/tagged/css)

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