Due to browser performance implications I can't use box-shadow CSS property because I have many similarly looking elements on my page that should have same looking style including shadow. That's the reason I would like to implement shadows using traditional PNG imagery.
Facts
My elements have predefined and more importantly fixed pixel width
They have fluid height (auto) depending on their content
They have content directly in the element and some child elements will be positioned outside their border
CSS3 can be used but performance-critical parts (gradients, shadows...) should be avoided
CSS pseudo elements can be used without limitation
Requirements
There should be no additional wrapper element added in order to have fluid shadow
Application should run smoothly on mobile browsers - shadows seem to slow down performance significantly on mobile devices since their processing power is much lower than desktop computers.
Possible direction
I thought of using :before and :after pseudos to display top-to-bottom and bottom shadows on the containing element, but these pseudos display within their parent element and positioning parent z-index higher than these children has no effect.
Visual demo of end result
This JSFiddle Demo in pure CSS3 that I would like to achieve but using PNG shadows. In reality there are numerous of these boxes so you can imagine mobile browsers are struggling with all these shadows.
Item is one such box (see blow) that needs PNG shadow. Left menu is child element positioned outside of the box.
Display in Chrome
HTML
<div class="item">
<menu>
<li>Yes</li>
<li>No</li>
<li>Maybe</li>
</menu>
<div class="content">
Some content
</div>
</div>
CSS3 LESS
.item {
position: relative;
width: 300px;
background-color: #fff;
box-shadow: 0 0 10px #ccc;
margin: 20px 20px 20px calc(20px + 3.5em);
min-height: 5em;
&:first-child {
margin-top: 0;
}
&:after {
content: "";
position: absolute;
top: 0;
left: 0;
width: 10px;
height: 5em;
background-color: #fff;
}
menu {
position: absolute;
top: 0;
left: -3.5em;
width: 3.5em;
margin: 0;
border: 0;
padding: 0;
list-style: none;
background-color: #fff;
box-shadow: 0 0 10px #ccc;
li a {
display: block;
text-align: center;
padding: 2px 0;
}
}
.content {
padding: .75em 1em;
}
}
Probably I am missing something, but looks like you want something in this way:
demo
The CSS is
.base {
width: 300px;
height: 150px;
font-size: 100px;
font-weight: bolder;
background-color: lightgreen;
position: relative;
z-index: auto;
}
.base:after {
content: '';
position: absolute;
top: 30px;
left: 30px;
background-color: green;
z-index: -1;
width: 100%;
height: 100%;
}
.child {
position: absolute;
left: 150px;
top: 50px;
border: solid 1px black;
color: red;
}
And just change the background of the :after to your image.
I have applied this solution to your fiddle.
The relevant CSS is for the before pseudo element:
.item:before {
content: "";
position: absolute;
top: -10px;
left: -10px;
right: -10px;
bottom: -10px;
z-index: -1;
background-image: url(http://placekitten.com/100/100);
background-repeat: no-repeat;
background-size: 100% 100%;
}
I have used a kitten picture, that is being scaled to cover all the needed size. Just change that to whatever you want.
I needed to do it that way because I had onky a pseudo element available.
The key for that to work (and where you probably had the difficulty) is to add z-index: auto to .item
Updated demo
Well, I had said that it wasn't posible, but I have find a way.
The standard technique would be to use 2 elements, just to avoid stretching the image (as you said). The problem is that we only have 1 pseudo element available.
The solution then would be to use 1 pseudo element, but with 2 backgrounds, to solve the issue.
CSS (only relevant part)
.item:before {
background-image: url(http://placekitten.com/320/10), url(http://placekitten.com/320/500);
background-repeat: no-repeat;
background-size: 100% 9px, 100% calc(100% - 9px);
background-position: left bottom, left top;
}
We will need an image (the first one) only 10 px in height, to cover the bottom shadow. And another one, with enough height to cover the maximumitem posible, and that will be used for the remaining part of the shadow. The dark part is that we need now a calc() height, with limited support. (anyway, better than border image)
demo 3
In this simplified example I have 4 circles, each with varying border-width and I am trying to maintain equal line height in each to keep them horizontally aligned.
However the border width seems to effect the line height (despite being technically outside the box?)
Is there anyway to solve this without manually adjusting each line-height?
width: 50px;
height: 50px;
border-radius: 50px;
border: 1px solid #1daeec;
line-height: 50px;
Example: http://jsfiddle.net/vcJ3G/
You can remove the line-height, use display:table-cell instead, and add vertical-align:middle; to your stat class.
jsFiddle example
.stat {
display: table-cell;
width: 50px;
height: 50px;
border-radius: 50px;
border: 1px solid #1daeec;
text-align: center;
margin: 10px;
font-size: 16px;
color: #1daeec;
text-transform: uppercase;
vertical-align:middle;
}
Your css works fine all you have to do is remove some from top section
* {
margin: 0px;
padding: 0px;
}
http://jsfiddle.net/techsin/vcJ3G/15/
Came across this and thought myself how is it possible to do it without using table-cell, my solution probably not the best, but I just decide to share it anyway.
http://codepen.io/svdovichenko/pen/rObzqM?editors=110
adding <span>1</span> (can use class inside spam didn't use for this example)
.stat{
position: relative;
}
and
span {
position: absolute;
top: 50%;
left: 50%;
margin-right: -50%;
transform: translate(-50%, -50%);
}
First time really using the pseudo :after selector. Not sure if the problem I'm running into is a limitation of it or I'm just missing something obvious.
Here's my live code.
li.current:after {
border-width: 1px 1px 0 0;
content: ' ';
background: #256f9e;
display: block;
height: 13px;
position: absolute;
width: 10px;
top: 6;
margin:0px auto;
z-index: 99;
transform: rotate(-224deg);
-webkit-transform: rotate(-224deg);
-moz-transform: rotate(-224deg);
-ms-transform: rotate(-224deg);
-o-transform: rotate(-224deg);
transform-origin: 50% 50%;
-webkit-transform-origin: 50% 50%;
-moz-transform-origin: 50% 50%;
-ms-transform-origin: 50% 50%;
-o-transform-origin: 50% 50%;
text-align: center;
float: center;
}
I've created a little triangle (Or rather a box that has been rotated to look like a triangle). I want it centered within the <li></li> but can't figure it out using my normal methods.
The things that have failed (in no particular order):
text-align: center;
float: center;
margin: 0 auto;
margin-right: 0;
margin-left: 0;
What am I missing? I doubt it matters, but I'm using AngularJS. Thought I'd mention it in case there is a known conflict between Angular & Pseudo selectors (which I doubt).
Thanks.
The issue is your use of absolute positioning & the method you're using to try and center it. If you position an element absolutely, the ol' margin: 0 auto; method won't work to center the thing. I point you to an explanation as to why this is at the end of the question, but in case you just want this to work let's get to the solution first.
Here's some working code. View it on JSFiddle
#tool-menu li {
...
position: relative;
}
li.current:after {
...
position: absolute;
width: 10px;
top: 6;
left: 50%;
margin-left: -5px;
}
Let's break down what's going on here.
Setting up a new Containing Block
In your original Fiddle, the pseudoelement is positioned absolutely relative to the viewport. An example might be the best way to show what this means, and why we don't want this. Consider setting it to top: 0. This would keep it latched to the top of the browser window (or, in this case, the JSFiddle frame), rather than the parent (the li). So, if our menu happened to be at the bottom of the page, or even moving around, the pseudoelement would be floating independent from it, stuck to the top of the page.
This is the default behavior of an absolutely positioned element when you don't explicitly set the position on any parent elements. What we want is to have its position defined relative to the parent. If we do this then the pseudoelement sticks with the parent, no matter where it happens to be.
To make this happen, you need to set the parent, #tool-menu li, to be explicitly positioned (which means setting it to be anything other than position: static). If you choose to use position: relative;, it won't change the computed location of the parent on the page, and does the thing we want. So that's why I used that one.
In technical terms, what we're doing here is creating a new containing block for the child.
Positioning the Pseudoelement
Now that our absolute positioning will be determined in relation to the parent, we can take advantage of the fact that we can use percentages to define where to place the child. In this case, you want it centered, so I set it be left: 50%.
If you do just this, though, you'll see that this lines up the left edge of the pseudoelement at 50%. This isn't what we want – we want the center of the pseudoelement to be at the middle. And that's why I added the negative margin-left. This scoots it over a bit to line the middle up with the center of the parent.
And once we do that, it's centered! Brilliance!
Why didn't my margin: auto; work?
The auto value of a margin is calculated from a fairly complex algorithm. At times, it computes to 0. I know from experience that this is one such instance of that happening, though I haven't yet traced my way through the algorithm to see exactly why. If you'd like to run through it, take a look at the spec most browsers have most likely implemented.
Using calc to center
You can also use the calc function in css to center the pseudo element.
Note: This isn't supported in IE8 and below (caniuse) but you can provide a fallback for older browsers.
View it on this code pen. I'm also using MarkP's css border method to draw the triangle.
li.current:after {
content: '';
display: block;
height: 0;
position: absolute;
width: 0;
overflow: hidden;
bottom: -5px;
left: calc(50% - 5px);
z-index: 2;
border-top: 5px #256f9e solid;
border-left: 5px transparent solid;
border-right: 5px transparent solid;
}
Wouldn't be better to just define the width as a percentage, make it a block element and text-align it in the center?
"float: center;" is invalid, and won't work. Mixing floated and absolute positioned elements are a sure way to get trouble with your layout as they don't really work that well togheter.
Try something like this:
li.current:after {
content: 'YOUR CONTENT';
display: block;
width: 100%;
text-align: center; }
Using margin:auto to center
As long as the element has a width declared you can use the absolute centering method.
To use this method the right and left properties must be set to 0 for margin: auto to be effective.
This method can be expanded to implement horizontal centering as well.
see link for full info:
http://www.smashingmagazine.com/2013/08/09/absolute-horizontal-vertical-centering-css/
li.current:after {
content: "";
position: absolute;
display: block;
right: 0;
bottom: -5px;
left: 0;
margin: auto;
border-width: 5px;
border-style: solid;
border-color: transparent;
border-top-color: #256f9e;
width: 200px;
height: 200px;
}
ul {
list-style-type: none;
padding: 0;
margin: 0;
}
<div>
<ul>
<li class="current"></li>
</ul>
</div>
Not directly related (have already voted up jmeas) but you may also find it easier to use the CSS border trick to make the triangle. e.g.
li.current:after {
content: '';
display: block;
height: 0;
position: absolute;
width: 0;
overflow:hidden;
bottom: 0;
left: 50%;
margin: 0 0 -5px -5px;
z-index: 99;
border-top: 5px #256f9e solid;
border-left: 5px transparent solid;
border-right: 5px transparent solid;
}
Similar tactics as to what jmeas has suggested with regards to the vertical positioning. We align to the bottom and then use a negative margin-bottom to push this out to the desired location.
With transform: translate() centering can be accomplished without a fixed size. This is because translate(<x>%) will use the (psuedo-)element's own size, while left and margin-left will use the container's size. By using these together we can therefore find the exact center-point.
tl;dr
To center vertically:
.container {
position: relative;
}
.container:after {
top: 50%;
transform: translateY(-50%);
}
To center horizontally:
.container {
position: relative;
}
.container:after {
left: 50%;
transform: translateX(-50%);
}
Full example
.container {
position: relative;
display: inline-block;
background: #4aa;
color: white;
padding: .5ex 1ex;
}
.container:after {
content: ":after";
position: absolute;
background: #a4a;
color: white;
padding: .5ex 1ex;
/* position below container */
top: 100%;
/* move right by 50% of containers width */
left: 50%;
/* move left by 50% of own width */
transform: translateX(-50%);
}
<p class="container">
Container with content
</p>
This may be the simplest way to do it:
.child_class::after{
position: absolute;
content: 'YourContentHere';
width: 100%;
text-align: center;
top: 50%;
}
the simplest way to do this -
With pesudo element :after or :before use display: inline-block;
Try something like this:
content: url(../images/no-result.png);
display: inline-block;
width: 100%;
text-align: center;
Using display: grid to center ::before
...worked nice for me. I'm using fa-Icons on this page and centered them within an element with 50% border-radius:
i {
font-size: 0.9rem;
border: 1px solid white;
border-radius: 50%;
width: 30px;
aspect-ratio: 1;
margin-inline: 5px;
}
i::before {
width: 100%;
height: 100%;
display: grid;
place-items: center;
}
This tutorial can help you to make center CSS pseudo-elements.
https://techidem.com/centering-pseudo-before-after-elements-content/
h2 {
text-align: center;
color: #181818;
padding-bottom: 20px;
margin-bottom: 35px;
border-bottom: 1px solid #eaeaea;
position: relative;
}
h2::after {
content: "";
width: 70px;
height: 4px;
background-color: #ff0000;
left: calc( 100% - ( 50% + 35px ) );
position: absolute;
display: block;
bottom: 0;
}
<h2>Most Recent Posts</h2>
You may use container queries with grid layout
element {
container-type: size;
&::after {
content: '';
position: absolute;
width: 100cqw;
height: 100cqh;
display: grid;
place-items: center;
}
}
Container queries: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Container_Queries
I personally don't really like the idea to change position attribute or do some margin manipulation. I think the easiest way is two lines of CSS:
.element::after {
/* your css */
line-height: initial;
vertical-align: initial;
}
And there is no need to touch the parent.
I am having some problems with my DIV, it wont display over a a DIV that has a web user control in it. Below you can find my css. I believe I have done everything right and am hoping that someone can maybe see an error that I have made and help me out. If you need any other code let me know. I also wonder if its just IE rendering it wrong? Thanks for looking.
The Popup CSS:
{
background: #ececec;
position:absolute;
top: 236px;
left: 201px;
height: auto;
width: 280px;
border: solid 1px gray;
z-index: 50;
text-align:left;
padding-left: 5px;
padding-top: 5px;
padding-bottom: 15px;
font-size: 8pt;
}
The Activity DIV (same the div above just changed position)
{
border: solid 2px #A9C5EB;
position: absolute;
top: 353px;
left: 290px;
width: 710px;
height: 227px;
font-size: small;
overflow: scroll;
overflow-x: hidden;
background-color: #F8FBFE;
z-index: 2;
}
To know the HTML is essential to fix your problem.
What is the html that contains your popup? Is it relative to the body tag or some other element? Is the containing element position: relative;?
Try setting the containing element's z-index and position:
#my-container {
position: relative;
z-index: 1;
}
See this SO post about absolute positioning.
On a side note, check out IE-7.js which fixes many IE browser issues, including - AFAIK - this bug.
I want to display a noscript warning when users have javascript disabled, in the same way StackOverflow does.
I use this html:
<noscript>
<div id="noscript-warning">
Este sitio funciona mejor con JavaScript habilitado. Descubrí
cómo habilitarlo.
</div>
</noscript>
and this css:
#noscript-warning
{
font-family: Arial,Helvetica,sans-serif;
position: fixed;
top: 0;
left: 0;
width: 100%;
z-index: 101;
text-align: center;
font-weight: bold;
font-size: 12pt;
color: white;
background-color: #AE0000;
padding: 10px 0;
display: block;
}
#noscript-warning a
{
color: #FFFFC6;
}
#container
{
width: 98%;
margin: auto;
padding: auto;
background-color: #fff;
color: black;
border-style: solid;
border-color: #3E4F4F;
border-width: 1px 2px 2px 1px;
line-height: 130%;
}
where #container is the main content element of my template.
When the noscript tag is visible, it appears in front of some content. I don't want that, the content should be displayed below the warning.
How can I do that?
If you want the behavior of position: fixed AND need to push the initial content down from the top, you can include a second div in your noscript area. Give this div visibility: hidden and a height equal to the height of the div with position: fixed.
The problem is with you setting position: fixed on the warning. You can't really expect the page's content to move around that, since you're fixing it to the top of the browser window. What would happen when you scroll down? The whole page's content rearranges itself to go around the warning?
Do you want the warning to be stuck at the top of the browser window even if they scroll? If not, position: fixed isn't what you're looking for.