Why is vertical-align: middle not working on my span or div?

Deep Dive: Vertical alignment in CSS

Vertical alignment is a complex topic in CSS. It's like trying to get the last Pringle chip from the can - seemingly simple, but there's a surprisingly high level ofinconvenience involved. Vertical-align property that works best with inline or inline-block elements has been historically hard to use with block-level elements like divs. But, with flexbox, the whole game has changed. It's like using a fork to get those last chips, smooth and effective.

Stretching the Limits: Alternative centering strategies

Vintage tables display

Way before the superhero flexbox came along, we had table display properties. The display: table; and the display: table-cell; combo allows vertical-align: middle; to work as expected, provided you are okay with a bit of time travel:

.parent {
  display: table;
  height: 200px;
  /* Define height as desired. Pretty much like adjusting the time machine's dial. */
}

.child {
  display: table-cell;  /* Turn your div into a cell because cells behave! */
  vertical-align: middle;  /* The div listens, finally! */
}
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The absolute transform charm

For sizing elements dynamically or just for fun, combine absolute positioning with CSS transforms to center the element, no calculus required:

.parent {
  position: relative;
}

.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);  /* Magic spell for center levitation */
}


Remember, the child element might require extra care with this method. It's like telling a child to go halfway to a destination, then take half of the remaining distance, and so on. They will get pretty close to the destination but might need some assistance for the last bit.

Listening to the line-height lullaby

Want to center a single line of text? Simply set line-height equivalent to the container's height. Who knew lines could sing so well?

.parent {
  line-height: 100px;  /* Matching the height of the container */
}

.child {
  display: inline-block;
  line-height: normal;  /* To let the text behave normally, the deep-sea creature in its comfortable environment */
}


This works beautifully for single lines of text and can get a bit tricky with multiple lines or larger content. It's like fitting an elephant into a Mini Cooper; doable, but not ideal.

Taking care of the elderly: Handling browser compatibility

Flexbox is the future, but we must take care of the past too. Remember our old friend Internet Explorer? Well, you might need to babysit it a little. Always specify vendor prefixes when using flexbox to ensure every browser, old and new, understands your instructions correctly.

.parent {
  display: -ms-flexbox;  /* IE 10's private invitation to the Flexbox party */
  display: flex;
  -ms-flex-align: center;  /* Because IE 10 special, okay? */
  align-items: center;
}


You could hand-write fallbacks, or use an amazing tool such as Autoprefixer to handle this repetition for you. It will take the timeless task off your hands so you have more time to enjoy the party.

Further tweaking for centering

Adding contrast with line-height

The line-height property can significantly impact the positioning of text. For example, setting the line-height equal to the container's height will center your text. Handy, right? However, the font-size and family can knock it off-center a bit, so be sure to test your typefaces!

Border Patrol

If something still doesn't seem quite right, look at your styles again. Are you adding border dimensions or padding? Remember, the border is like the wall around a city. And the CSS box model considers it when aligning items. Give your div a pep talk about staying inside the lines.

Vertical-align: Not totally useless

Contrary to popular belief, vertical-align isn't a total waste. Have you tried aligning inline or inline-block elements within a line of text? vertical-align can help you here. It also comes in handy when you need to position buttons within a navigation bar.

Wrapping it up – Practical examples

A comprehensive jsfiddle or code sandbox showcasing all these methods would be like the cherry on top of a CSS sundae. Being able to edit and experiment with the code in real-time would bring these concepts home like nothing else.