This heading explains the workings of tasks or instructions that you have just completed.

You will also find some other learning aids in the book, including:

These are short multiple-choice questions intended to help you test your own understanding.

These practical challenges and give you ideas for experimenting with what you have learned.

You will also find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "You may notice that we used the Unix command rm to remove the Drush directory rather than the DOS del command."

A block of code is set as follows:

<meta name="viewport" content="width=device-width, initial-scale=1">

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

<picture alt="responsive images">
  <source src=big.jpg media="min-width:768px">
  <source src=medium.jpg media="min-width:320px">
  <source src=small.jpg>
  <img src=medium.jpg alt="responsive images">
</picture>

Any command-line input or output is written as follows:

compass watch

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "On the Select Destination Location screen, click on Next to accept the default destination."

You can download the example code files for all Packt books you have purchased from your account at http://www.packtpub.com. If you purchased this book elsewhere, you can visit http://www.packtpub.com/support and register to have the files e-mailed directly to you.

Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you find a mistake in one of our books—maybe a mistake in the text or the code—we would be grateful if you would report this to us. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. If you find any errata, please report them by visiting http://www.packtpub.com/submit-errata, selecting your book, clicking on the errata submission form link, and entering the details of your errata. Once your errata are verified, your submission will be accepted and the errata will be uploaded to our website, or added to any list of existing errata, under the Errata section of that title.

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We appreciate your help in protecting our authors, and our ability to bring you valuable content.

You can contact us at <[email protected]> if you are having a problem with any aspect of the book, and we will do our best to address it.