Responsive Design for Web Pages responsive-design-for-web-pages

Design your web pages so that they adapt to the client viewport in which they are displayed. With responsive design, the same pages can be effectively displayed on multiple devices in both orientations. The following image demonstrates some ways in which a page can respond to changes in viewport size:

Develop Adobe Experience Manager (AEM) applications that generate HTML5 pages that adapt to multiple window sizes and orientations. For example, the following ranges of viewport widths correspond with various device types and orientations

See the following topics for information about implementing responsive design behavior:

As you design, use Sidekick to preview your pages for various screen sizes.

Before you develop before-you-develop

Before you develop the AEM application that supports your web pages, several design decisions should be made. For example, you need to have the following information:

Application structure application-structure

The typical AEM application structure supports all responsive design implementations:

Using media queries using-media-queries

Media queries enable the selective use of CSS styles for page rendering. AEM development tools and features enable you to effectively and efficiently implement media queries in your applications.

The W3C group provides the Media Queries recommendation that describes this CSS3 feature and the syntax.

Creating the CSS file creating-the-css-file

In your CSS file, define media queries based on the properties of the devices that you are targeting. The following implementation strategy is effective for managing styles for each media query:

The We.Retail Media sample uses this strategy to define styles in the site design. The CSS file used by We.Retail is located at */apps/weretail/clientlibs/clientlib-site/less/grid.less.

The following table lists the files in the css child folder.

The css.txt file in the /etc/designs/weretail/clientlibs folder lists the CSS files that the client library folder includes. The order of the files implements style precedence. Styles are more specific as the device size decreases.

#base=css

style.css
 bootstrap.css

responsive-1200px.css
 responsive-980px-1199px.css
 responsive-768px-979px.css
 responsive-767px-max.css
 responsive-480px.css

Tip: Descriptive file names let you easily identify the targeted viewport size.

Using Media Queries with AEM Pages using-media-queries-with-aem-pages

Include the client library folder in the JSP script of your page component to generate the CSS file that includes the media queries, and to reference the file.

<ui:includeClientLib categories="apps.weretail.all"/>

The JSP script generates the following HTML code that references the style sheets:

<link rel="stylesheet" href="/etc/designs/weretail/clientlibs-all.css" type="text/css">
<link href="/etc/designs/weretail.css" rel="stylesheet" type="text/css">

Previewing for specific devices previewing-for-specific-devices

See previews of your pages in different viewport sizes to test the behavior of your responsive design. In Preview mode, Sidekick includes a Devices drop-down menu that you use to select a device. When you select a device, the page changes to adapt to the viewport size.

To enable the device preview in Sidekick, you must configure the page and the MobileEmulatorProvider service. Another page configuration controls the list of devices that appears in the Devices list.

Adding the Devices List adding-the-devices-list

The Devices list appears in Sidekick when your page includes the JSP script that renders the Devices list. To add the Devices list to Sidekick, include the /libs/wcm/mobile/components/simulator/simulator.jsp script in the head section of your page.

Include the following code in the JSP that defines the head section:

<cq:include script="/libs/wcm/mobile/components/simulator/simulator.jsp"/>

To see an example, open the /apps/weretail/components/page/head.jsp file in CRXDE Lite.

Registering Page components for simulation registering-page-components-for-simulation

To enable the device simulator to support your pages, register your page components with the MobileEmulatorProvider factory service and define the mobile.resourceTypes property.

When working with AEM there are several methods of managing the configuration settings for such services; see Configuring OSGi for full details.

For example, to create a [sling:OsgiConfig](/docs/experience-manager-64/deploying/configuring/configuring-osgi.md#adding-a-new-configuration-to-the-repository) node in your application:

Add the following node property:

Specifying the device groups specifying-the-device-groups

To specify the device groups that appear in the Devices list, add a cq:deviceGroups property to the jcr:content node of the root page of your site. The value of the property is an array of paths to the device group nodes.

Device group nodes are located in the /etc/mobile/groups folder.

For example, the root page of the Geometrixx Media site is /content/geometrixx-media. The /content/geometrixx-media/jcr:content node includes the following property:

Use the Tools conosole to create and edit device groups.

Using adaptive images using-adaptive-images

You can use media queries to select an image resource to display in the page. However, every resource that uses a media query to conditionalize its use is downloaded to the client. The media query merely determines whether the downloaded resource is displayed.

For large resources such as images, downloading all resources is not an efficient use of the client’s data pipeline. To selectively download resources, use javascript to initiate the resource request after the media queries perform the selection.

The following strategy loads a single resource that is chosen using media queries:

Evaluating media queries using Javascript evaluating-media-queries-using-javascript

Implementations of the MediaQueryList interface that the W3C defines enable you to evaluate media queries using javascript. You can apply logic to the media query results and execute scripts that are targeted for the current window:

Selecting media-specific resources selecting-media-specific-resources

The W3C-proposed picture element uses media queries to determine the source to use for image elements. The picture element uses element attributes to assocate media queries with image paths.

The freely-available picturefill.js library provides similar functionality as the proposed picture element, and uses a similar strategy. The picturefill.js library calls window.matchMedia to evaluate the media queries that are defined for a set of div elements. Each div element also specifies an image source. The source is used when the media query of the div element returns true.

The picturefill.js library requires HTML code that is similar to the following example:

<div data-picture>
    <div data-src='path to default image'></div>
    <div data-src='path to small image'    data-media="(media query for phone)"></div>
    <div data-src='path to medium image'   data-media="(media query for tablet)"></div>
    <div data-src='path to large image'     data-media="(media query for monitor)"></div>
</div>

When the page is rendered, picturefull.js inserts an img element as the last child of the <div data-picture> element:

<div data-picture>
    <div data-src='path to default image'></div>
    <div data-src='path to small image'    data-media="(media query for phone)"></div>
    <div data-src='path to medium image'   data-media="(media query for tablet)"></div>
    <div data-src='path to large image'     data-media="(media query for monitor)"></div>
    <img src="path to medium image">
</div>

In an AEM page, the value of the data-src attribute is the path to a resource in the repository.

Implementing adaptive images in AEM implementing-adaptive-images-in-aem

To implement adaptive images in your AEM application, you need to add the required javascript libraries, and include the required HTML markup in your pages.

Libraries

Obtain the following javascript libraries and include them in a client library folder:

Tip: You can automatically concatenate multiple client library folders by embedding.

HTML

Create a component that generates the required div elements that the picturefill.js code expects. In an AEM page, the value of the data-src attribute is the path to a resource in the repository. For example, a page component can hard-code the media queries and the associated paths for image renditions in DAM. Or, create a custom Image component that enables authors to select image renditions or specify runtime rendering options.

The following example HTML selects from 2 DAM renditions of the same image.

<div data-picture>
    <div data-src='/content/dam/geometrixx-media/articles/meridien.png'></div>
    <div data-src='/content/dam/geometrixx-media/articles/meridien.png/jcr:content/renditions/cq5dam.thumbnail.319.319.png'    data-media="(min-width: 769px)"></div>
    <div data-src='/content/dam/geometrixx-media/articles/meridien.png/jcr:content/renditions/cq5dam.thumbnail.140.100.png'   data-media="(min-width: 481px)"></div>
</div>

Understanding image rendering in AEM understanding-image-rendering-in-aem

To customize image rendering, you should understand the default AEM static image rendering implementation. AEM provides the Image component and an image-rendering servlet that work together to render images for web page. The following sequence of events occur when the Image component is included in the page’s paragraph system:

For example, the JSP of the Image component generates the following HTML element:

<img title="My Image" alt="My Image" class="cq-dd-image" src="/content/mywebsite/en/_jcr_content/par/image_0.img.jpg/1358372073597.jpg">

When the browser loads the page, it requests the image using the value of the src attribute as the URL. Sling decomposes the URL:

The image_0 node has a jcr:resourceType value of foundation/components/image, which has a sling:resourceSuperType value of foundation/components/parbase. The parbase component includes the img.GET.java script that matches the selector and the file name extension of the request URL. CQ uses this script (servlet) to render the image.

To see the source code of the script, use CRXDE Lite to open the /libs/foundation/components/parbase/img.GET.java
file.

Scaling images for the current viewport size scaling-images-for-the-current-viewport-size

Scale images at runtime according to the characteristics of the client viewport to provide images that conform to the principles of responsive design. Use the same design pattern as static image rendering, using a servlet and an authoring component.

The component needs to perform the following tasks:

The servlet that processes the image request needs to perform the following tasks:

Available solutions

AEM installs the following implementations that you can use or extend.

Understanding the Adaptive Image component understanding-the-adaptive-image-component

The Adaptive Image component generates calls to the Adaptive Image Component Servlet to render an image that is sized according to the device screen. The component includes the following resources:

Adding the DIV elements adding-the-div-elements

The adaptive-image.jsp script includes the following code that generates div elements and media queries:

<div data-picture data-alt='<%= alt %>'>
    <div data-src='<%= path + ".img.320.low." + extension + suffix %>'       data-media="(min-width: 1px)"></div>                                        <%-- Small mobile --%>
    <div data-src='<%= path + ".img.320.medium." + extension + suffix %>'    data-media="(min-width: 320px)"></div>  <%-- Portrait mobile --%>
    <div data-src='<%= path + ".img.480.medium." + extension + suffix %>'    data-media="(min-width: 321px)"></div>  <%-- Landscape mobile --%>
    <div data-src='<%= path + ".img.476.high." + extension + suffix %>'      data-media="(min-width: 481px)"></div>   <%-- Portrait iPad --%>
    <div data-src='<%= path + ".img.620.high." + extension + suffix %>'      data-media="(min-width: 769px)"></div>  <%-- Landscape iPad --%>
    <div data-src='<%= path + ".img.full.high." + extension + suffix %>'     data-media="(min-width: 1025px)"></div> <%-- Desktop --%>

    <%-- Fallback content for non-JS browsers. Same img src as the initial, unqualified source element. --%>
    <noscript>
        <img src='<%= path + ".img.320.low." + extension + suffix %>' alt='<%= alt %>'>
    </noscript>
</div>

The path variable contains the path of the current resource (the adaptive-image component node). The code generates a series of div elements with the following structure:

<div data-scr = "*path-to-parent-node*.adaptive-image.adapt.*width*.*quality*.jpg" data-media="*media query*"></div>

The value of the data-scr attribute is a URL that Sling resolves to the Adaptive Image Component Servlet that renders the image. The data-media attribute contains the media query that is evaluated against the client properties.

The following HTML code is an example of the div elements that the JSP generates:

<div data-src='/content/geometrixx-media/en/events/the-lineup-you-ve-been-waiting-for/jcr:content/article-content-par/adaptive_image.adapt.320.low.jpg'></div>
    <div data-src='/content/geometrixx-media/en/events/the-lineup-you-ve-been-waiting-for/jcr:content/article-content-par/adaptive_image.adapt.320.medium.jpg'    data-media="(min-width: 320px)"></div>
    <div data-src='/content/geometrixx-media/en/events/the-lineup-you-ve-been-waiting-for/jcr:content/article-content-par/adaptive_image.adapt.480.medium.jpg'    data-media="(min-width: 321px)"></div>
    <div data-src='/content/geometrixx-media/en/events/the-lineup-you-ve-been-waiting-for/jcr:content/article-content-par/adaptive_image.adapt.476.high.jpg'     data-media="(min-width: 481px)"></div>
    <div data-src='/content/geometrixx-media/en/events/the-lineup-you-ve-been-waiting-for/jcr:content/article-content-par/adaptive_image.adapt.620.high.jpg'     data-media="(min-width: 769px)"></div>
    <div data-src='/content/geometrixx-media/en/events/the-lineup-you-ve-been-waiting-for/jcr:content/article-content-par/adaptive_image.adapt.full.high.jpg'     data-media="(min-width: 1025px)"></div>

Changing the image size selectors changing-the-image-size-selectors

If you customize the Adaptive Image component and change the width selectors, you must also configure the Adaptive Image Component Servlet to support the widths.

Understanding the Adaptive Image Component Servlet understanding-the-adaptive-image-component-servlet

The Adaptive Image Component Servlet resizes a JPEG image according to a specified width, and sets the JPEG quality.

The interface of the Adaptive Image Component Servlet the-interface-of-the-adaptive-image-component-servlet

The Adaptive Image Component Servlet is bound to the default Sling servlet and supports the .jpg, .jpeg, .gif, and .png file extensions. The servlet selector is img.

Therefore, Sling resolves HTTP request URLs of the following format to this servlet:

*path-to-node*.img.*extension*

For example, Sling forwards HTTP requests with the URL http://localhost:4502/content/geometrixx/adaptiveImage.img.jpg to Adaptive Image Component Servlet.

Two additional selectors specify the requested image width and JPEG quality. The following example requests an image of width 480 pixels and medium quality:

http://localhost:4502/content/geometrixx/adaptiveImage.adapt.480.MEDIUM.jpg

Supported image properties

The servlet accepts a finite number of image widths and qualities. The following widths are supported by default (in pixels):

The full value indicates no scaling.

The following values for JPEG quality are supported:

The numeric values are 0.4, 0.82, and 1.0, respectively.

Changing the default supported widths

Use the Web Console (http://localhost:4502/system/console/configMgr) or a sling:OsgiConfig node to configure the supported widths of the Adobe CQ Adaptive Image Component Servlet.

For information about how to configure AEM services, see Configuring OSGi.

Implementation details implementation-details

The com.day.cq.wcm.foundation.impl.AdaptiveImageComponentServlet class extends the AbstractImageServlet class. The AdaptiveImageComponentServlet source code is located in the /libs/foundation/src/impl/src/com/day/cq/wcm/foundation/impl folder.

The class uses Felix SCR annotations to configure the resource type and file extension that the servlet is associated with, and the name of the first selector.

@Component(metatype = true, label = "Adobe CQ Adaptive Image Component Servlet",
        description = "Render adaptive images in a variety of qualities")
@Service
@Properties(value = {
    @Property(name = "sling.servlet.resourceTypes", value = "foundation/components/adaptiveimage", propertyPrivate = true),
    @Property(name = "sling.servlet.selectors", value = "img", propertyPrivate = true),
    @Property(name = "sling.servlet.extensions", value ={
            "jpg",
            "jpeg",
            "png",
            "gif"
    }, propertyPrivate = true)
})

The servlet uses the Property SCR annotation to set the default supported image quality and dimensions.

@Property(value = {
            "320", // iPhone portrait
            "480", // iPhone landscape
            "476", // iPad portrait
            "620" // iPad landscape
    },
            label = "Supported Widths",
            description = "List of widths this component is permitted to generate.")

The AbstractImageServlet class provides the doGet method that processes the HTTP request. This method determines the resource that is associated with the request, retrieves resource properties from the repository, and returns them in an ImageContext object.

The AdaptiveImageComponentServlet class overrides the createLayer method. The method obtains the path of the image resource and the requested image width from the ImageContext object. It then calls the methods of the info.geometrixx.commons.impl.AdaptiveImageHelper class, which performs the actual image scaling.

The AdaptiveImageComponentServlet class also overrides the writeLayer method. This method applies the JPEG quality to the image.

Image Reference Modification Servlet (Geometrixx Common) image-reference-modification-servlet-geometrixx-common

The sample Image Reference Modification Servlet generates size attributes for the img element to scale an image on the web page.

Calling the servlet calling-the-servlet

The servlet is bound to cq:page resources and supports the .jpg file extension. The servlet selector is image. Therefore, Sling resolves HTTP request URLs of the following format to this servlet:

path-to-page-node.image.jpg

For example, Sling forwards HTTP requests with the URL http://localhost:4502/content/geometrixx/en.image.jpg to Image Reference Modification Servlet.

Three additional selectors specify the requested image width, height, and (optionally) quality. The following example requests an image of width 770 pixels, height 360 pixels, and of medium quality.

http://localhost:4502/content/geometrixx/en.image.770.360.MEDIUM.jpg

Supported image properties

The servlet accepts a finite number of image dimensions and quality values.

The following values are supported by default (widthxheight):

The following values for image quality are supported:

When working with AEM there are several methods of managing the configuration settings for such services; see Configuring OSGi for full details.

Specifying the image resource specifying-the-image-resource

The image path, dimensions, and quality values must be stored as properties of a node in the repository:

When authoring a page, use Sidekick to specify the image and add the image node to the page properties:

Implementation details implementation-details-1

The info.geometrixx.commons.impl.servlets.ImageReferenceModificationServlet class extends the AbstractImageServlet class. If you have the cq-geometrixx-commons-pkg package installed, the ImageReferenceModificationServlet source code is located in the /apps/geometrixx-commons/src/core/src/main/java/info/geometrixx/commons/impl/servlets folder.

The class uses Felix SCR annotations to configure the resource type and file extension that the servlet is associated with, and the name of the first selector.

@Component(metatype = true, label = "Adobe CQ Image Reference Modification Servlet",
        description = "Render the image associated with a page in a variety of dimensions and qualities")
@Service
@Properties(value = {
    @Property(name = "sling.servlet.resourceTypes", value = NameConstants.NT_PAGE, propertyPrivate = true),
    @Property(name = "sling.servlet.selectors", value = "image", propertyPrivate = true),
    @Property(name = "sling.servlet.extensions", value = "jpg", propertyPrivate = true)
})

The servlet uses the Property SCR annotation to set the default supported image quality and dimensions.

@Property(label = "Image Quality",
            description = "Quality must be a double between 0.0 and 1.0", value = "0.82")
@Property(value = {
                "256x192", // Category page article list images
                "370x150", // "Most popular" desktop & iPad & carousel min-width: 1px
                "480x200", // "Most popular" phone
                "127x127", // article summary phone square images
                "770x360", // article summary, desktop
                "620x290", // article summary, tablet
                "480x225", // article summary, phone (landscape)
                "320x150", // article summary, phone (portrait) and fallback
                "375x175", // 2-column article summary, desktop
                "303x142", // 2-column article summary, tablet
                "1170x400", // carousel, full
                "940x340",  // carousel min-width: 980px
                "770x300",  // carousel min-width: 768px
                "480x190"   // carousel min-width: 480px
            },
            label = "Supported Resolutions",
            description = "List of resolutions this component is permitted to generate.")

The AbstractImageServlet class provides the doGet method that processes the HTTP request. This method determines the resource that is associated with the call, retrieves resource properties from the repository, and saves them in an ImageContext object.

The ImageReferenceModificationServlet class overrides the createLayer method and implements the logic that determines the image resource to render. The method retrieves a child node of the page’s jcr:content node named image. An Image object is created from this image node, and the getFileReference method returns the path to the image file from the fileReference property of the image node.

Developing a fluid grid developing-a-fluid-grid

AEM enables you to efficiently and effectively implement fluid grids. This page explains how you can integrate your fluid grid or an existing grid implementation (such as Bootstrap) into your AEM application.

If you are not familiar with fluid grids, see the Introduction to Fluid Grids section at the bottom of this page. This introduction provides an overview of fluid grids and guidance for designing them.

Defining the grid using a Page component defining-the-grid-using-a-page-component

Use page components to generate the HTML elements that define the content blocks of the page. The ClientLibraryFolder that the page references provides the CSS that controls the layout of the content blocks:

For example, the sample geometrixx-media application contains the media-home component. This page component inserts two scripts, which generate two div elements of class row-fluid:

<div class="page-content">
    <div class="row-fluid">
        <div class="span12">
            <cq:include path="grid-12-par" resourceType="foundation/components/parsys" />
        </div>
    </div>
    <div class="row-fluid">
        <div class="span8">
            <cq:include path="grid-8-par" resourceType="foundation/components/parsys" />
        </div>
        <div class="span4">
            <cq:include path="grid-4-par" resourceType="foundation/components/parsys" />
        </div>
    </div>
</div>

Scaling the Page component grid scaling-the-page-component-grid

The design that is associated with the geometrixx-media page component (/etc/designs/geometrixx-media) contains the clientlibs ClientLibraryFolder. This ClientLibraryFolder defines CSS styles for row-fluid classes, span* classes, and span* classes that are children of row-fluid classes. Media queries enable styles to be redefined for different viewport sizes.

The following example CSS is a subset of those styles. This subset focuses on span12, span8, and span4 classes, and media queries for two viewport sizes. Notice the following characteristics of the CSS:

/* default styles (no media queries) */
 .span12 { width: 940px }
 .span8 { width: 620px }
 .span4 { width: 300px }
 .row-fluid .span12 { width: 100% }
 .row-fluid .span8 { width: 65.95744680851064% }
 .row-fluid .span4 { width: 31.914893617021278% }

@media (min-width: 768px) and (max-width: 979px) {
 .span12 { width: 724px; }
 .span8 {     width: 476px; }
 .span4 {     width: 228px; }
 .row-fluid .span12 {     width: 100%;}
 .row-fluid .span8 {     width: 65.74585635359117%; }
 .row-fluid .span4 {     width: 31.491712707182323%; }
}

@media (min-width: 1200px) {
 .span12 { width: 1170px }
 .span8 { width: 770px }
 .span4 { width: 370px }
 .row-fluid .span12 { width: 100% }
 .row-fluid .span8 { width: 65.81196581196582% }
 .row-fluid .span4 { width: 31.623931623931625% }
}

Repositioning content in the Page component grid repositioning-content-in-the-page-component-grid

The pages of the sample Geometrixx Media application distribute rows of content blocks horizontally in wide viewports. In smaller viewports, the same blocks are distributed vertically. The following example CSS shows the styles that implement this behavior for the HTML code that the media-home page component generates:

/* default styles (no media queries) */
    .row-fluid [class*="span"] {
        width: 100%;
        float: left;
}

@media (max-width: 767px) {
    [class*="span"], .row-fluid [class*="span"] {
        float: none;
        width: 100%;
    }
}

Modularize your Page components tip-modularize-your-page-components

Modularize your components to make efficient use of the code. Your site likely uses several different types of pages, such as a welcome page, an article page, or a product page. Each type of page contains different types of content and likely use different layouts. However, when certain elements of each layout are common across multiple pages, you can re-use the code that implements that part of the layout.

Use page component overlays

Create a main page component that provides scripts for generating the various parts of a page, such as head and body sections, and header, content, and footer sections within the body.

Create other page components that use the main page component as the cq:resourceSuperType. These components include scripts that override the scripts of the main page as needed.

For example, the goemetrixx-media application includes the page component (the sling:resourceSuperType is the foundation page component). Several child components (such as article, category, and media-home) use this page component as the sling:resourceSuperType. Each child component includes a content.jsp file that overrides the content.jsp file of the page component.

Re-use scripts

Create multiple JSP scripts that generate row and column combinations that are common for mulitple page components. For example, the content.jsp script of the article and media-home components both reference the 8x4col.jsp script.

Organize CSS styles by targeted viewport size

Include CSS styles and media queries for different viewport sizes in separate files. Use client library folders to concatenate them.

Inserting components into the page grid inserting-components-into-the-page-grid

When components generate a single block of content, generally the grid that the page component establishes controls the placement of the content.

Authors should be aware that the content block can be rendered in various sizes and relative positions. Content text should not use relative directions to refer to other content blocks.

If necessary, the component should provide any CSS or javascript libraries that are required for the HTML code that it generates. Use a client library folder inside the component to generate the CSS and JS files. To expose the files, create a dependency or embed the library in another client library folder below the /etc folder.

Sub-grids

If the component contains multiple blocks of content, add the content blocks inside a row to establish a sub-grid on the page:

For example, the /apps/geometrixx-media/components/2-col-article-summary component generates two columns of content. The HTML that it generates has the following structure:

<div class="row-fluid mutli-col-article-summary">
    <div class="span6">
        <article>
            <div class="article-summary-image">...</div>
            <div class="social-header">...</div>
            <div class="article-summary-description">...</div>
            <div class="social">...</div>
        </article>
    </div>
</div>

The .row-fluid .span6 selectors of the page’s CSS applies to the div elements of the same class and structure in this HTML. However, the component also includes the /apps/geometrixx-media/components/2-col-article-summary/clientlibs client library folder:

For example, the following styles are included in the /apps/geometrixx-media/components/2-col-article-summary/clientlibs/css/responsive-480px.css file:

@media (max-width: 480px) {
    .mutli-col-article-summary .article-summary-image {
        float: left;
        width: 127px;
    }
    .mutli-col-article-summary .article-summary-description {
        width: auto;
        margin-left: 127px;
    }
    .mutli-col-article-summary .article-summary-description h4 {
        padding-left: 10px;
    }
    .mutli-col-article-summary .article-summary-text {
        margin-left: 127px;
        min-height: 122px;
        top: 0;
    }
}

Introduction to fluid grids introduction-to-fluid-grids

Fluid grids enable page layouts to adapt to the dimensions of the client viewport. Grids consist of logical columns and rows that position the blocks of content on the page.

Using HTML5 technology you can implement the grid and manipulate it to adapt page layouts to different viewport sizes:

Using discrete widths using-discrete-widths

For each range of viewport widths that you are targeting, use a static page width and content blocks of constant width. When manually resizing a browser window, changes to content size occur at discrete window widths (also known as breakpoints). Consequently, page designs are more closely adhered to, maximizing the user experience.

Scaling the grid scaling-the-grid

Use grids to scale content blocks to adapt to different viewport sizes. Content blocks span a specific number of columns. As column widths increase or decrease to fit different viewport sizes, the width of the content blocks increase or decrease accordingly. Scaling can support both large- and medium-sized viewports that are wide enough to accommodate the side-by-side placement of content blocks.

Repositioning content in the grid repositioning-content-in-the-grid

The size of content blocks can be constrained by a minimum width, beyond which scaling is no longer effective. For smaller viewports, the grid can be used to vertically distribute blocks of content rather than horizontally.

Designing the grid designing-the-grid

Determine the columns and rows that you need to position the blocks of content on your pages. Your page layouts determine the number of columns and rows that span your grid.

Number of columns

Include enough columns to horizontally position the content blocks in all of your layouts, for all viewport sizes. You should use more columns than are currently needed to accommodate future page designs.

Row contents

Use rows to control the vertical positioning of content blocks. Determine the content blocks that share the same row:

Grid implementations grid-implementations

Create CSS classes and styles to control the layout of the content blocks on a page. Page designs are often based on the relative size and position of content blocks within the viewport. The viewport determines the actual size of the content blocks. Your CSS needs to account for the relative and the absolute sizes. You can implement a fluid grid using three types of CSS classes:

Targeted viewport widths (and their associated media queries) demarcate discrete widths that are used for a page layout.

Widths of content blocks widths-of-content-blocks

Generally, the width style of content block classes are based on the following characteristics of your page and grid:

The CSS includes a series of media queries that use the following structure:

@media(query_for_targeted_viewport){

  .class_for_container{ width:absolute_page_width }
  .class_for_row { width:100%}

  /* several selectors for content blocks   */
  .class_for_content_block1 { width:absolute_block_width1 }
  .class_for_content_block2 { width:absolute_block_width2 }
  ...

  /* several selectors for content blocks inside rows */
  .class_for_row .class_for_content_block1 { width:relative_block_width1 }
  .class_for_row .class_for_content_block2 { width:relative_block_width2 }
  ...
}

Use the following algorithm as a starting point for developing the element classes and CSS styles for your pages.

Positioning Content Blocks in Rows positioning-content-blocks-in-rows

Use the float style of the .row-fluid class to control whether the content blocks in a row are arranged horizontally or vertically.

Add the style to the .row-fluid selector inside each media query. Set the value according to the page layout that you are using for that media query. For example, the following diagram illustrates a row that distributes content horizontally for wide viewports, and vertically for narrow viewports.

The following CSS could implement this behavior:

@media (min-width: 768px) and (max-width: 979px) {
   .row-fluid {
       width:100%;
       float:left
   }
}

@media (max-width:480px){
    .row-fluid {
       width:100%;
       float:none
   }
}

Assigning classes to content blocks assigning-classes-to-content-blocks

For the page layout of each viewport size you are targeting, determine the number of columns that each content block spans. Then, determine which class to use for the div elements of those content blocks.

When you have established the div classes, you can implement the grid using your AEM application.