Supporting IE – Part Three: The Last Resort! CSS Grid tips, hacks and workarounds.

This post is part three of a three-part series about providing support for IE11 when working with CSS Grid.
Part One – Providing Basic CSS Grid Support.
Part Two – Finding ways to use CSS Grid properties that are not supported.

Ok, so by now if you have followed my first two posts you should have something in IE11 that looks pretty close to the layout you’ve created in modern browsers. But there is nearly always something that just won’t work, no matter how hard you try to make it, and that is when you maybe need to take a different approach…

Using Feature Queries.

I briefly covered Feature Queries in part two. They are another super cool addition to the CSS3 specification and look and work in a similar way to @media queries. But instead of detecting device characteristics, they look for CSS properties that are supported by the browser being used.

These are a great way to progressively enhance your CSS because generally it is considered good practice to first write CSS that works in all browsers, and then enhance it for modern browsers by adding new properties, but only if they are supported.

A typical feature query would look like this:

@supports( display: grid ) {
	...
}

If display: grid is supported by the browser, then any code that is wrapped inside is run. If it isn’t, then the code isn’t run either.

The times I most often find that I need to take this approach is when I’m trying to provide support for auto-placement. This is a pretty rare edge case and I’ve only really needed when I don’t know how many rows there will be so can’t manually place each item.

For example, I recently worked on a WordPress project where the designer had outlined a very specific 12 column grid for a content area and exactly how many columns the component within should span. This seemed an ideal opportunity to use CSS Grid as it would allow me to position all of the content components (Gutenberg Blocks) within a grid exactly as the designer wanted, and they would then autoflow down the page.

In modern browsers, this worked really well, but unfortunately, it didn’t work in IE. Because the content blocks are created by a user, there is no way to know whether a page would have 20 blocks or only 3 to be able to explicitly place them all.

In this case, the decision was made to drop using CSS Grid on the content area for IE and use flexbox instead, but still continue to use Grid in modern browsers. This was achieved by using the @supports feature query:

.grid__container {
	display: flex;
	flex-flow: row wrap;

	@supports( display: grid ) {
		display: grid;
		grid-template-columns: repeat( 3, 1fr );
	}
}

Here we’ve set the container to display: flex in all browsers, but then in browsers that support Grid, it is set to display: grid instead. The only thing left after that is a few specific styles for the grid__items.

Why isn’t this styling a layout twice?

This seems like you are defining two layouts for the same page, and you would be forgiven for dismissing this as a lot of extra time and effort, but it isn’t really.

What is nice about the CSS display property is, once display: grid has been set, it automatically cancels out any other display properties and any associated properties. Therefore we don’t need to add a lot of extra CSS to cancel them out manually.

For example, here we’ve used display: flex. This gets cancelled out by display: grid, which we would expect because it’s further down in the cascade. However, all other flexbox properties are now void as well. We’ve now set our grid columns using grid-template-columns, this tells us how many items per row there would be and their maximum size. The content is then auto-placed within this grid. Flexbox properties like flex-direction and flex-grow etc. don’t need to be cancelled out because they no longer have any effect.

Similarly, had we gone truly old school and created a grid using display: block, floats and margins. As soon as display: grid; is applied, display: block is cancelled out and because we’ve defined our columns and the content is auto-placed, float has no effect either. The only property that would need cancelling is the margins applied (see grid-gap in part two).

Using @supports not ().

So it’s clear that feature queries are pretty neat. However, being totally honest, when trying to provide support for IE they are nearly always a last resort for me. This is because, I usually only find I need them when I’m testing my layout in IE11 and discovered that because of an edge case, none of the fallbacks and techniques I’ve already outlined will work. At this point you’re no longer trying to progressively enhance your CSS, you are instead trying to retro-fit support.

Rather than having to add the additional flexbox fallback to already existing styles and risk causing side-effects in other browsers, then add in the @supports rule so that modern browsers can use grid instead, wouldn’t it be great if we could add our fallbacks only if something is not supported?

@supports can do this by using the not keyword:

@supports not ( display: grid ) {
	display: grid;
}

This looks great and should be exactly what is needed. However, there is one major problem with this approach and it has tripped me up multiple times. IE11 doesn’t support feature queries and will, therefore, ignore it completely. Meaning any and all fallbacks we write specifically for this will be ignored.

IE Feature Detection Mixin.

This mixin was shared with me by some of my colleagues at Human Made, when I was working on a project where I did have to retrofit support for IE11 after I had almost completed the project. It was a total lifesaver!

@mixin ie-query {
	@media all and
		( -ms-high-contrast: none ),
		( -ms-high-contrast: active ) {

		@content;
	}
}

Essentially it is a standard media query set to detect -ms-high-contrast. Because the feature being detected is prefixed with -ms, it only applies to Microsoft browsers, and, high-contrast is only available in IE10 +, therefore any CSS written inside this mixin will only be applied in Internet Explorer:

body {
	@include ie-query {
		background-color: red;
	}
}

In this example, the main page body is given a background-color of red, which is only applied in IE. Great! This is basically what I had wanted from @supports not ()

In an ideal world, this shouldn’t really be needed, we should allow the cascade to work its magic, set styles for older browsers first and allow them to be overwritten by styles for newer browsers if they are supported.

However, we’ve all been on a project where we’ve had to retrofit support afterwards. To do things “the right way” could involve a massive amount of refactoring, and we don’t want any changes we make to support IE11 to affect the work we’ve already done either. This mixin allows us to target only what we need to.

Sending Headers.

This is something that we (hopefully) rarely have to consider these days, but if you are working on a project for a large organisation whose IT infrastructure is locked down tight, and your stakeholders have no control over their own settings. It’s very likely they are all forced to use IE11 still and worse…. Compatibility Mode will be switched on 😱

Luckily, even though all of the articles I found on the internet about this are super old now, there is an easy fix:

<meta http-equiv="X-UA-Compatible" content="IE=edge">

By adding this meta tag to the head of your website, we are specifying that all IE browser versions should use a minimum of the Edge rendering engine.

This may not be a CSS fix but, if the websites you are building are being viewed in compatibility mode, then without this one change none of your CSS Grid fallbacks will work.

Finished.

Ok, so now we are finished.

This is my toolkit for providing support for IE11 whether, I write it in from the beginning of the project and progressively enhance my code base or I have to retrofit a project to support IE11 afterwards.

I haven’t covered all aspects of the CSS Grid Specification, or all of the ways you can create your layouts to work in IE, I’ve tried to stick to methods and techniques that I need most often. There are a lot of different and creative ways to provide support, for example, there is an argument to not use any of the -ms- prefixes and instead create your layout using floats, or flexbox and nest your Grid related CSS inside feature queries. Which is a perfectly good solution as well.

Personally, I rarely need to support browsers older than IE11 now, so I don’t like to create my layouts using floats first. I find that by using the toolkit I have outlined in these posts, I can create fallbacks using the -ms- prefixes just as easily, and allow SASS to output most of the repetition for me, saving me development time as well.

Hopefully, this gives you all a solid idea of how you can provide support for IE when working with CSS Grid. There will come a day when we no longer need to provide support for IE11, but until that day, I hope people find this series useful. 🙂


Further Reading:

Supporting IE – Part Two: Finding ways to use CSS Grid properties that are not supported.

This post is part two of a three-part series about providing support for IE11 when working with CSS Grid.
Part One – Providing Basic CSS Grid Support.
Part Three – The last resort! CSS Grid tips, hacks and workarounds.

(This article assumes a reasonable knowledge of SASS, CSS and some understanding of using CSS Grid.)

In my last post, I mentioned that there are some small tweaks and edge cases that will still have to be accounted to provide full support for IE11, and most of these happen when using properties that are not supported in IE at all.

Rachel Andrew already does an excellent job of outlining what isn’t supported in her article, Should I try to use the IE implementation of CSS Grid?, and I don’t want to repeat that, so I won’t list everything again in this post. Instead, I’m only going to focus on the three main features that I regularly have to find a solution to somehow.

Auto-placement.

The eagle-eyed of you may have noticed that while I did discuss placing items within the grid in my previous post, I deliberately didn’t mention auto-placement. This is because it is the one feature that I find can become a headache to try to provide IE11 fallbacks for.

The problem comes when you don’t need to explicitly place your content in a grid, for example, an archive page on a blog. On pages like these, we want our grid items to be placed one per column and autoflow down the page, creating as many rows as needed. With auto-placement, this is made easy and we don’t have to provide any CSS to do that in modern browsers. In IE11 though, because you haven’t explicitly set the position of each grid item, they will all sit in column one, row one, on top of each other. Which is definitely not good.

Explicitly placing each grid item will fix this for you but, if you have a three-column grid with four rows, and a total of twelve grid items that all need to be explicitly placed, that will mean a lot of extra CSS. It would look something like this:

.grid__item:first-child {
	-ms-grid-column: 1; 
	-ms-grid-column-span: 1;
	grid-column: 1 / 2;
	-ms-grid-row: 1; 
	-ms-grid-row-span: 1;
	grid-row: 1 / 2;
}

.grid__item:nth-child(2) {
	-ms-grid-column: 2;
	-ms-grid-column-span: 1;
	grid-column: 2 / 3;
	-ms-grid-row: 1;
	-ms-grid-row-span: 1;
	grid-row: 1 / 2;
}

...

Here I’ve used nth-child to select each grid__item and explicitly place it on the grid. This is now a lot of code to place each item, and if you then consider adding media queries into the mix then you can imagine the code soup it will create. This is pretty horrible and definitely deserving of the  😢🔥🗑emojis.

Letting SASS do the clean up.

We can’t avoid needing all of this extra code, unfortunately, but there are a few things we can do to clean it up and automate using Sass Mixins. For example, I first saw this mixin on CSS Tricks some time ago, and it provides a simple solution to reduce the number of lines we have to write each time:

@mixin grid-child( $col-start, $col-end, $row-start, $row-end ) {
	-ms-grid-column: $col-start;
	-ms-grid-column-span: $col-end - $col-start;
	grid-column: #{$col-start} / #{$col-end};
	-ms-grid-row: $row-start;
	-ms-grid-row-span: $row-end - $row-start;
	grid-row: #{$row-start} / #{$row-end};
}

This is a simple SASS mixin (simple because there isn’t any loops or functions being used), which has extracted the repeated code for placing each grid__item so that instead of repeating six lines of code on each property, we can re-use the mixin instead, making our outputted SCSS look like:

.grid__item:first-child {
	@include grid-child( 1, 2, 1, 2 );
}

.grid__item:nth-child(2) {
	@include grid-child( 2, 3, 1, 2  );
}

...

We could take this a step further and automate the output including each nth-child. In the example mentioned above, we know that there should be a three-column grid, so we could create the output for column placements like this:

@mixin ie-grid-columns(
	$columns: 3,
) {
	// Columns.
	@for $i from 1 through $columns {
		> :nth-child(#{$columns}n + #{$i}) {
			-ms-grid-column: ( ( $i + $columns ) - $columns );
			grid-column: ( ( $i + $columns ) - $columns ) / span 1;
		}
	}
}

Here, we start by defining a set number of columns, in this example, the value is 3. We then use the @for SASS loop to assign the nth-child value to each .grid__item. For example, when looping through, if $i is equal to 2, then the nth-child becomes 3n + 2 allowing us to select all grid items in multiples of 3 starting from 2 (2, 5, 8, 11 etc.).

Now instead of having to write out each .grid__item:nth-child() {} and apply a mixin with different values, we can apply this mixin to our grid container and it will apply each nth-child to the children in that container, in order, and the corresponding grid-column placement.

.grid__container {
	@include ie-grid-columns;
}

This saves us having to manually write out lots of extra code and all of the CSS needed to place items in columns in IE11 is still outputted when the SCSS is compiled.

A similar process can also be applied to rows. We know that because we have twelve posts and three columns there should be four rows. The mixin would look like this:

@mixin ie-grid-rows(
	$posts: 12
) {
	@for $i from 1 through $posts {
		> :nth-child(#{$i}) {
			@if $i >= 1 and $i <= 3 {
				-ms-grid-row: 1;
				grid-row-start: 1;
			}
			@if $i >= 4 and $i <= 6 {
				-ms-grid-row: 2;
				grid-row-start: 2;
			}
			@if $i >= 7 and $i <= 9 {
				-ms-grid-row: 3;
				grid-row-start: 3;
			}
			@if $i >= 10 and $i <= 12 {
				-ms-grid-row: 4;
				grid-row-start: 4;
			}
		}
	}
}

This time we set a number of posts, then using the @for loop again we loop through each grid__item, check whether $i is within a set range and then position it in the correct row.

Admittedly this isn’t anywhere near as elegant as the mixin for columns. It would be super nice to be able to select the first three grid__items, then the next three, then the next three, and so on without having to use an @if statement with hard-coded values, and I’m sure there is someone out there that can figure out the maths to do that. However, this does still go a long way towards helping to cut down the amount of code you have to write to get around the issue of IE11 not supporting auto-placement.

Note: While fact-checking these articles, I discovered that we could also use grid-template-areas here, which Autoprefixer does support and would create fallbacks for us rather than having to use mixins.

However, I haven’t ever used this technique in a production environment so I’m not covering it in this article. If you want to read more, check out CSS Grid in IE: CSS Grid and the New Autoprefixer.

repeat()

As I mentioned when discussing the use of Autoprefixer in part one, the repeat() function, while super cool, is not supported in IE. There is the [] syntax which you can use, and this is a perfectly acceptable solution, however, it does require you to manually add it in so that there are two lines of code. Most often this will occur when using grid-template-columns or grid-template-rows. For example:

-ms-grid-columns: 1fr[12];
grid-template-columns: repeat( 12, 1fr );

Letting SASS automate repeat.

Another way to ensure we have twelve columns that are all 1fr is to manually write 1fr out twelve times. Nobody wants to do this, but we could easily use SASS mixins to automate this for us. For example:

@mixin ie-repeatable-columns( $columns, $width ) {
	$r: '';
	@for $i from 1 through $columns {
		$r: $r + ' ' + $width;
	}
	-ms-grid-columns:#{$r};
	grid-template-columns: repeat( #{$columns}, #{$width} );
}

In this mixin, we have the option to add a custom number of columns and width, using $columnsand $width. We then create the variable $r. This will store the outputted value for the columns.

Using the @for loop again we loop through all of the columns and add the inputted $width for each column to the $r variable. The last thing we do is we then output the CSS properties and generated values for the grid columns.

Tip: Notice that in the output of this mixin we have interpolated both $r, $columns and $width. Without this interpolation, these values would be outputted inside “”, which would create invalid CSS. By interpolating them (wrapping them in #{}) they are outputted without quotation marks.

See further reading at the bottom of this post for more information on interpolation.

This allows us to use the mixin like this:

.grid__container {
	ie-repeatable-columns( 5, 1fr );
}

Which when the SASS has been compiled to CSS would output:

.grid__container {
	-ms-grid-columns: 1fr 1fr 1fr 1fr 1fr;
	grid-template-columns: repeat( 5, 1fr );
}

Either using [] or a mixin would work to support the repeat() function in IE. However, with some modification the sass mixin could be made to also help support grid-gap (see below), whereas I don’t believe using [] instead of repeat() can.

grid-gap

Grid-gap is a nice little feature which works especially well when using the fr unit to calculate column and row sizes. Unfortunately, though, this super useful feature only has partial support in IE11.

If we had a three column grid with a 10px grid-gap, for modern browsers we would define it like this:

.grid__container {
	display: grid;
	grid-gap: 10px;
	grid-template-columns: repeat( 3, 1fr );
}

When providing support for IE though, there is no prefixed version for grid-gap, instead we can create the gaps by using the prefixed -ms-grid-columns instead. For example:

-ms-grid-columns: 1fr 10px 1fr 10px 1fr;

Now, we still have three columns that are 1fr wide each, but now we’ve also added two grid-gaps that are 10px wide as well!

The good news here is that this is something that Autoprefixer can automatically fix for us. The caveat though is that it will only work if both grid-template-columns and grid-template-rows are defined. This is because grid-gap defines both the gap between columns and rows, therefore Autoprefixer will want to apply 10px gaps to both properties. The full code with IE support for this grid would look like:

.grid__container {
	display: -ms-grid;
	display: grid;
	grid-gap: 10px;
	-ms-grid-columns: 1fr 10px 1fr 10px 1fr;
	grid-template-columns: repeat( 3, 1fr );
	-ms-grid-columns: 1fr 10px 1fr 10px 1fr;
	grid-template-columns: repeat( 3, 1fr );
}

This example does away with all of the fallbacks for supporting the repeat() function mentioned above. We could modify the sass mixin to include grid-gaps as well, although, this does start to get pretty complicated. Or we could use a feature query.

Using the @supports feature query

Another approach would be to make use of the @supports feature query instead, like this:

.grid__container {
	display: grid;
	grid-gap: 10px;
}

.grid__item {
	margin: 5px;

	@supports( display: grid ) {
		margin: 0;
	}
}

What is happening here is, grid-gap is set on the grid__container, this would be applied in modern browsers but because it is not supported in IE it would be ignored. A margin of 5px is then added to all sides of each grid__item, to create a gap around and is globally applied in all browsers. Then using @supports, if the browser used to view the website supports display: grid, the margin is removed from each grid__item. This is because grid-gap is already being applied in modern browsers and we don’t need to apply margins as well. In the case of IE11, the feature query is not supported and therefore the margin: 0 within is ignored.

This might seem a little long winded but it could be really useful if the grid you are creating is fairly complex and automating or autoprefixing don’t work as needed.

Finished?

Unfortunately, there is no avoiding the extra lines of code that are needed to ensure we provide full support for CSS Grid in IE11. But in a lot of cases, by using a preprocessor, we can take most of the pain away of having to write a lot of repetitive CSS.

However, there is always at least one area of your website where your IE11 fallbacks simply won’t play nicely and you have to resort to some more drastic measures. In the last post in this series I will go through some tips (and hacks) I’ve used when really nothing else will work.


Further Reading:


CSS GRID Fallback for IE using SASS Lists

When placing items in a CSS Grid, in modern browsers we can rely on auto-placement to do most of the heavy lifting for us, however when providing support for IE10 & 11, we have to write CSS code to explicitly place all of your items in the Grid.

This is because auto-placement is not supported in IE10 & 11 and sadly, it is also one area where Autoprefixer can’t help us either 😦

Writing all of this additional code can often be a pain so I’ve created a utility using SASS Lists to help make it a little less painful.

But why can’t Autoprefixer help?

Autoprefixer in its simplest form will look at each line of CSS, check it against caniuse.com and if it is not supported by a certain browser, but a prefixed version is available, it will add a line that includes the vendor prefix. For example:

::placeholder {
  color: gray;
}

Would output the following after Autoprefixer has been run:

::-webkit-input-placeholder {
  color: gray;
}
:-ms-input-placeholder {
  color: gray;
}
::-ms-input-placeholder {
  color: gray;
}
::placeholder {
  color: gray;
}

Great right?

But back to CSS GRID…

If we wanted to have a grid of four items, two in each column and row, we can achieve that easily by defining the grid-template-columns and grid-template-rows on the container:

.grid-container {
    display: grid;
    grid-template-columns: repeat( 2, 1fr );
    grid-template-rows: repeat( 2, 1fr );
}

Thanks to CSS GRIDs auto-placement we don’t need to do anything else, each grid- item will be repeated twice across both columns and rows and will fit 1 fraction so will appear equal in height and width. YAY!

The problem with Internet Explorer

As mentioned at the beginning, Internet Explorer does not support auto-placement. To be able to use GRID, we have to explicitly position grid-items. If we don’t do that then all of the items will stack in the first cell of the grid 😦

This means thats our code goes from:

.grid-container {
    display: grid;
    grid-template-columns: repeat( 2, 1fr );
    grid-template-rows: repeat( 2, 1fr );
}

to:

.grid-container {
    display: -ms-grid;
    grid-template-columns: repeat( 2, 1fr );
    -ms-grid-columns: 1fr 1fr;
    grid-template-rows: repeat( 2, 1fr );
    -ms-grid-rows: 1fr 1fr;
}

.grid-item-1 {
    -ms-grid-column: 1;
    -ms-grid-row: 1;
}

.grid-item-2 {
    -ms-grid-column: 2;
    -ms-grid-row: 1;
}

.grid-item-3 {
    -ms-grid-column: 1;
    -ms-grid-row: 2;
}

.grid-item-4 {
    -ms-grid-column: 2;
    -ms-grid-row: 2;
}

😦

But it’s not all bad, looking at all of those -ms- vendor prefixes used, this is where Autoprefixer has stepped in and fixed it for us right? Sadly no.

Because we haven’t used grid-column and grid-row first, (why would we when we don’t need the grid items to be explicitly placed in any browsers other than IE? ) Autoprefixer can’t see that there is anything that needs to be prefixed.

So, thanks to IE there is now a lot more code for our grid which we have to add manually and it is all starting to get very messy…

SASS to the rescue!

There isn’t a lot we can do about the amount of code needed to ensure our Grid works in IE as well, but we can tidy it up using SASS Lists and a @for loop so that it looks better in our codebase like this:

$total-items: 4;
$ms-layout: 1 1,
            2 1,
            1 2,
            2 2;

@for $i from 1 through $total-items {
    $position: nth( $ms-layout, $i );

    .grid-item-#{$i} {
	-ms-grid-column: nth($position, 1);
	-ms-grid-row: nth($position, 2);
    }
}

There is quite a lot going on in this little snippet so let’s break it down a bit.

This is the number of grid-items on the grid.

$total-items: 4;

This is our SASS List, it contains four rows, each with the position of the grid-column and then grid-row.

$ms-layout: 1 1,
            2 1,
            1 2,
            2 2;

Next we start a loop using $total-items so that the loop does not execute more than four times. Loop through each row using nth to retrieve the values for each grid-item in the $ms-layout list that correlates with where in the loop we are, and create a new list called $position.

The new list contains only the two values relevant to that grid-item. For example grid-item-3 would have a sass list that looks like $position: 1 2;

@for $i from 1 through $total-items {
    $position: nth( $ms-layout, $i );

Finally, we output the column and row positions:

    .grid-item-#{$i} {
	-ms-grid-column: nth($position, 1);
	-ms-grid-row: nth($position, 2);
    }

Using nth again we get the first value of $position for the column and the second value for row. Done!

Here is a complete example using six grid-items:

I’m sure many of you are thinking “Why bother going to this extra effort?”

This technique doesn’t stop the need for all of those extra lines of code to ensure your grid works in IE, and once the SASS has been compiled it will still output all of those lines, so you could stop at writing the vendor prefixes for IE and it would be backwards compatible.

But, if you are like me and find yourself continually copying and pasting them from project to project, it does keep your SASS a little bit neater and for me that is always worth the effort 🙂

Some Further Reading:

CSS Multicolour border and gradient

Recently I was asked to create a container that had a top border with a gradient applied to fade the border from blue to purple. But, the container also needed a background gradient that matched the border, and also faded out to white before the content started. Like this:

There are lots of ways to apply a gradient to a border, many illustrated in this excellent CSS Tricks article, and it is pretty easy to apply gradients to a background-image by using linear-gradient now as well.

The difficulty came when I realised I wanted to apply three different affects (border gradient, background gradient, and fade to white) to the same container without adding any additional markup.

In the end I achieved this by making use of pseudo elements and applying only two effects in total. Here is my solution:

First I started with my container markup and base styles for that.

<div class="container">
</div>
.container {
   display: block;
   width: 100vw;
   height: 100vh;
}

For the sake of this demo, I have set my container to the full width and height of the screen. Next we set both a :before and an :after pseudo element on the container.

.container {
   [...]

   &::before,
   &::after {
     content: "";
     position: absolute;
     left: 0;
     right: 0;
   }
}

Now that we have the foundations set all that is left to do is apply the effects.

.container {
   [...]

   &::before {
     background-image: linear-gradient( to right, #6a26b5, #007bc2 );
     height: 100px;
     top: 0;
   }

   &::after {
     background-image: linear-gradient( to top, #ffffff, rgba( 255, 255, 255, 0.7 ) );
     height: 90px;
     top: 10px;
   }
}

To break this down, the :before sets the first of two background gradients. This gradient is linear and flows from purple on the left to blue on the right. It is positioned at the top of the container, because we set position: absolute on both, and is 100px in height (you could easily change this to em or whichever unit you are using in your project).

The :after sets the second background gradient. This gradient is also linear but flows from a solid white at the bottom to a white with an opacity of 0.7, using the rgba() colour function, to the top. Which, when overlaid over the top of the colour gradient set on the :before, creates the fade out affect.

The final effect to achieve here is to create the border with the same gradient. To do that, all that is needed is to move the start position of the white gradient so that instead of starting at 0 it starts lower and displays some of the original solid gradient. In this example, the border needed to be 10px so I added:

top: 10px;
height: 90px;

The top value is then subtracted from the value of the height so that both :before and :after effects finish in the some position and preserve the smoothness of the fade out. If you only needed a the border to be 5px, then it would look like:

top: 5px;
height: 95px;

The full CSS Looks like:

.container {
  display: block;
  width: 100vw;
  height: 100vh;

  &::before,
  &::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
  }

  &::before {
    background-image: linear-gradient( to right, #6a26b5, #007bc2 );
    height: 100px;
    top: 0;
  }

  &::after {
    background-image: linear-gradient( to top, #ffffff, rgba( 255, 255, 255, 0.7 ) );
    height: 90px;
    top: 10px;
  }
}

Here it is in action:

Using linear-gradient meant that although three effects were required, only two needed to be created. This gave a really small performance win because we’ve skipped a third effect that would have needed to be painted, and it is well supported by modern browsers as well. Only a few of the more advanced features are not fully supported by Microsoft IE & Edge. Check out the browser compatibility section on MDN for more advanced details.