CSS - Flexbox

Layout is where the browser figures out the geometric information for elements: their size and location in the page. Each element will have explicit or implicit sizing information based on the CSS that was used, the contents of the element, or a parent element. The process is called Layout in Chrome, Opera, Safari, and Internet Explorer. In Firefox it’s called Reflow, but effectively the process is the same.

Similarly to style calculations, the immediate concerns for layout cost are:

1. The number of elements that require layout.
2. The complexity of those layouts.

TL;DR

• Layout is normally scoped to the whole document.
• The number of DOM elements will affect performance; you should avoid triggering layout wherever possible.
• Assess layout model performance; new Flexbox is typically faster than older Flexbox or float-based layout models.
• Avoid forced synchronous layouts and layout thrashing; read style values then make style changes.

See the source link for details and solutions.

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Let me show you a way I recently discovered to center a bunch of elements around what I call the pivot. I promise you that funky HTML is out of the question and you won’t need to know any bleeding-edge CSS to get the job done.

[…]

[H]ere’s a sample of the HTML that drives this puzzle:

Here’s a generalized version of the [styles]. As you can see, it’s just 15 lines of simple CSS:

Here are the CSS ingredients we used for a media-query-less card component:

• The clamp() function helps resolve a “preferred” vs. “minimum” vs. “maximum” value.
• The flex-basis property with a negative value decides when the layout breaks into multiple lines.
• The flex-grow property is used as a unit value for proportional growth.
• The vw unit helps with responsive typography.
• The  object-fit property provides finer responsiveness for the card image, as it allows us to alter the dimensions of the image without distorting it.

Great answer by Michael_B on Stack Overflow:

Short Answer

If the goal is to create a grid with equal height rows, where the tallest cell in the grid sets the height for all rows, here’s a quick and simple solution:

• Set the container to grid-auto-rows: 1fr

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How it works

Grid Layout provides a unit for establishing flexible lengths in a grid container. This is the fr unit. It is designed to distribute free space in the container and is somewhat analogous to the flex-grow property in flexbox.

If you set all rows in a grid container to 1fr, let’s say like this:

grid-auto-rows: 1fr;

… then all rows will be equal height.

It doesn’t really make sense off-the-bat because fr is supposed to distribute free space. And if several rows have content with different heights, then when the space is distributed, some rows would be proportionally smaller and taller.

Except, buried deep in the grid spec is this little nugget:

7.2.3. Flexible Lengths: the fr unit

…

When the available space is infinite (which happens when the grid container’s width or height is indefinite), flex-sized (fr) grid tracks are sized to their contents while retaining their respective proportions.

The used size of each flex-sized grid track is computed by determining the max-content size of each flex-sized grid track and dividing that size by the respective flex factor to determine a “hypothetical 1fr size”.

The maximum of those is used as the resolved 1fr length (the flex fraction), which is then multiplied by each grid track’s flex factor to determine its final size.

So, if I’m reading this correctly, when dealing with a dynamically-sized grid (e.g., the height is indefinite), grid tracks (rows, in this case) are sized to their contents.

The height of each row is determined by the tallest (max-content) grid item.

The maximum height of those rows becomes the length of 1fr.

That’s how 1fr creates equal height rows in a grid container.

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Why flexbox isn’t an option

As noted in the question, equal height rows are not possible with flexbox.

Flex items can be equal height on the same row, but not across multiple rows.

This behavior is defined in the flexbox spec:

6. Flex Lines

In a multi-line flex container, the cross size of each line is the minimum size necessary to contain the flex items on the line.

In other words, when there are multiple lines in a row-based flex container, the height of each line (the “cross size”) is the minimum height necessary to contain the flex items on the line.

If you find yourself wrestling with CSS layout, it’s likely you’re making decisions for browsers they should be making themselves. Through a series of simple, composable layouts, Every Layout will teach you how to better harness the built-in algorithms that power browsers and CSS.

Even though Microsoft has explicitly told the world to stop using Internet Explorer 11, many organizations still have a significant enough IE11 user base that they have no choice but to build their products to acquiesce to the aging browser’s idiosyncratic demands.

Whether you are new to the world of building the front-end for Internet Explorer 11 compatibility or you are an old hand who knows their way around all the IE11 pitfalls, read on to learn more about:

• Choosing the right environment for debugging
• Dealing with unsupported JavaScript
• Tackling CSS layout issues
• Understanding the IE11 debugger

Armed with these tips, one should be able to quickly solve problems in the instance when a web application works perfectly on everything but IE11.

This looks like an excellent, accessible starting point for the priority navigation pattern:

Or the priority navigation pattern, or progressively collapsing navigation menu. We can name it in at least three ways.

There are multiple UX solutions for tabs and menus and each of them have their own advantages over another, you just need to pick the best for the case you are trying to solve. At design and development agency Kollegorna we were debating on the most appropriate UX technique for tabs for our client’s website…

We agreed it should be a one-liner because the amount of tab items is unknown and narrowed our options down to two: horizontal scroll and adaptive with “more” button. Firstly, the problem with the former one is that horizontal scroll as a feature is not always visually obvious for users (especially for narrow elements like tabs) whereas what else can be more obvious than a button (“more”), right? Secondly, scrolling horizontally using a mouse-controlled device isn’t a very comfortable thing to do, so we might need to make our UI more complex with additional arrow buttons. All considered, we ended up choosing the later option[.]