Flexible elements — CSS: Site Adaptability

• Additional materials
• Do it yourself

In the first project, we created a page with a fixed width of 1000 pixels. This approach has a right to life. But what happens if we open such a layout on a device with a resolution less than 1000 pixels wide? In that case, horizontal scrolling appears, which annoys users.

No one wants to constantly move the content to read a line or see a sidebar. Besides the obvious inconvenience, the user may not see that the scroll exists. Then he might miss a piece of content.

Let's create a container with a width of 800 pixels and add some styles and text. Inside the container, we'll put three blocks with a width of 245 pixels:

See the Pen css_adaptive_percent_1 by Hexlet (@hexlet) on CodePen.

In this example, the blocks take up a total of 735 pixels. Imagine that the page size has changed to 700 pixels. In this case, all three blocks won't fit on the page. Instead, there will be horizontal scrolling:

See the Pen css_adaptive_percent_1 by Hexlet (@hexlet) on CodePen.

The oveflow-x property emulates browser behavior on the container, which will hide content and add a scrollbar. Think of the .container block as a browser.

When computers and the Internet first appeared, screens were almost standardized. Several basic resolutions were popular so developers could fix the size of elements.

With the advent of mobile devices, laptops, and tablets, we got a variety of resolutions. It became inconvenient to work with the size of entire blocks. Scroll bars constantly appeared. If vertical scrolling is perceived well, then horizontal scrolling infuriates users.

Now developers cannot rely on specific sizes, so they calculate them based on the screen size. We can use percentages for this. Instead of specifying a block size in pixels, we can count it as a percentage of the parent block or the device's current screen resolution.

This approach is called fluid layout.

Let's make the three blocks fluid. To do that, we'll remove the fixed width of 245 pixels and replace the value with 33%. In this way, the three blocks will take up almost all the available space:

See the Pen css_adaptive_percent_2 by Hexlet (@hexlet) on CodePen.

Changing the size of pages or blocks will also change their size in a fluid layout. This feature also helps to create an adaptive site:

See the Pen css_adaptive_percent_2 by Hexlet (@hexlet) on CodePen.

In addition to the pros, this concept has some cons. What happens if the screen resolution is too small? Then our blocks will continue to shrink as long as they can find free space. Then the text inside the blocks can no longer fit and will go beyond its parent. Devices with such low resolutions are hard to find. But working with relative units, we should remember that blocks are shrinking until the end:

See the Pen css_adaptive_percent_3 by Hexlet (@hexlet) on CodePen.

The min-width style is a perfect way to solve this problem. Using it, we can set a stopping point, after which the container and the elements inside will stop shrinking.

The same approach helps to limit content stretching for large widths. More often than not, a site only needs 1200-1300 pixels wide to read text comfortably.

At higher resolutions, we stretch the content too much and get long lines, which are hard to perceive. In that case, we set the stopping point using the max-width rule, which specifies a value in absolute units such as pixels.

Additional materials

• min-width
• max-width

Do it yourself

Create a page on your computer with two blocks: a sidebar and a main content block. Make a fluid layout, using relative units, the max-width and the min-width properties. Don't forget to observe the layout's behavior, Using the mobile view emulation in your browser.