30 Seconds of CSS A curated collection of useful CSS snippets you can understand in 30 seconds or le…

<p>medium bookmark / Raindrop.io | Clearfix Ensures that an element self-clears its children. Note: This is only useful if you are still using float to build layouts. Please consider using a modern approach with flexbox layout or grid layout. HTML <div class=”clearfix”> <div class=”floated”>float a</div> <div class=”floated”>float b</div> <div class=”floated”>float c</div> </div> CSS .clearfix::after { […]</p>

Breakdown

medium bookmark / Raindrop.io |

Clearfix

Ensures that an element self-clears its children.

Note: This is only useful if you are still using float to build layouts. Please consider using a modern approach with flexbox layout or grid layout.

HTML

<div class="clearfix"> 
  <div class="floated">float a</div> 
  <div class="floated">float b</div> 
  <div class="floated">float c</div> 
</div>

CSS

.clearfix::after { 
  content: ""; 
  display: block; 
  clear: both; 
} 
.floated { 
  float: left; 
}

Demo

Explanation

.clearfix::after defines a pseudo-element.
content: '' allows the pseudo-element to affect layout.
clear: both indicates that the left, right or both sides of the element cannot be adjacent to earlier floated elements within the same block formatting context.

Browser support

✅ No caveats.

Custom text selection

Changes the styling of text selection.

HTML

<p class="custom-text-selection">Select some of this text.</p>

CSS

.custom-text-selection::selection { 
  background: red; 
  color: white; 
}

Demo

Select some of this text.

Explanation

::selection defines a pseudo selector on an element to style text within it when selected.

Browser support

⚠️ Requires prefixes for full support and is not actually in any specification.

https://caniuse.com/#feat=css-selection

Easing variables

Variables that can be reused for transition-timing-function properties, more powerful than the built-in ease, ease-in, ease-out and ease-in-out.

HTML

<div class="easing-variables"></div>

CSS

:root { 
  --ease-in-quad: cubic-bezier(0.55, 0.085, 0.68, 0.53); 
  --ease-in-cubic: cubic-bezier(0.55, 0.055, 0.675, 0.19); 
  --ease-in-quart: cubic-bezier(0.895, 0.03, 0.685, 0.22); 
  --ease-in-quint: cubic-bezier(0.755, 0.05, 0.855, 0.06); 
  --ease-in-expo: cubic-bezier(0.95, 0.05, 0.795, 0.035); 
  --ease-in-circ: cubic-bezier(0.6, 0.04, 0.98, 0.335); 
  --ease-out-quad: cubic-bezier(0.25, 0.46, 0.45, 0.94); 
  --ease-out-cubic: cubic-bezier(0.215, 0.61, 0.355, 1); 
  --ease-out-quart: cubic-bezier(0.165, 0.84, 0.44, 1); 
  --ease-out-quint: cubic-bezier(0.23, 1, 0.32, 1); 
  --ease-out-expo: cubic-bezier(0.19, 1, 0.22, 1); 
  --ease-out-circ: cubic-bezier(0.075, 0.82, 0.165, 1); 
  --ease-in-out-quad: cubic-bezier(0.455, 0.03, 0.515, 0.955); 
  --ease-in-out-cubic: cubic-bezier(0.645, 0.045, 0.355, 1); 
  --ease-in-out-quart: cubic-bezier(0.77, 0, 0.175, 1); 
  --ease-in-out-quint: cubic-bezier(0.86, 0, 0.07, 1); 
  --ease-in-out-expo: cubic-bezier(1, 0, 0, 1); 
  --ease-in-out-circ: cubic-bezier(0.785, 0.135, 0.15, 0.86); 
} 
.easing-variables { 
  width: 50px; 
  height: 50px; 
  background: #333; 
  transition: transform 1s var(--ease-out-quart); 
} 
.easing-variables:hover { 
  transform: rotate(45deg); 
}

Demo

Explanation

The variables are defined globally within the :root CSS pseudo-class which matches the root element of a tree representing the document. In HTML, :root represents the <html> element and is identical to the selector html, except that its specificity is higher.

Browser support

✅ No caveats.

https://caniuse.com/#feat=css-variables

Etched text

Creates an effect where text appears to be “etched” or engraved into the background.

HTML

<p class="etched-text">I appear etched into the background.</p>

CSS

.etched-text { 
  text-shadow: 0 2px white; 
  font-size: 1.5rem; 
  font-weight: bold; 
  color: #b8bec5; 
}

Demo

I appear etched into the background.

Explanation

text-shadow: 0 2px white creates a white shadow offset 0px horizontally and 2px vertically from the origin position.

The background must be darker than the shadow for the effect to work.

The text color should be slightly faded to make it look like it’s engraved/carved out of the background.

Browser support

✅ No caveats.

https://caniuse.com/#feat=css-textshadow

Gradient text

Gives text a gradient color.

HTML

<p class="gradient-text">Gradient text</p>

CSS

.gradient-text { 
  background: -webkit-linear-gradient(pink, red); 
  -webkit-text-fill-color: transparent; 
  -webkit-background-clip: text; 
}

Demo

Explanation

background: -webkit-linear-gradient(...) gives the text element a gradient background.
webkit-text-fill-color: transparent fills the text with a transparent color.
webkit-background-clip: text clips the background with the text, filling the text with the gradient background as the color.

Browser support

⚠️ Uses non-standard properties.

https://caniuse.com/#feat=text-stroke

Hairline border

Gives an element a border equal to 1 native device pixel in width, which can look very sharp and crisp.

HTML

<div class="hairline-border">text</div>

CSS

.hairline-border { 
  box-shadow: 0 0 0 1px; 
} 
@media (min-resolution: 2dppx) { 
  .hairline-border { 
    box-shadow: 0 0 0 0.5px; 
  } 
} 
@media (min-resolution: 3dppx) { 
  .hairline-border { 
    box-shadow: 0 0 0 0.33333333px; 
  } 
} 
@media (min-resolution: 4dppx) { 
  .hairline-border { 
    box-shadow: 0 0 0 0.25px; 
  } 
}

Demo

Text with a hairline border around it.

Explanation

box-shadow, when only using spread, adds a psuedo-border which can use subpixels*.
Use @media (min-resolution: ...) to check the device pixel ratio (1ddpx equals 96 DPI), setting the spread of the box-shadow equal to 1 / dppx.

Browser Support

⚠️ Needs alternate syntax and JavaScript user agent checking for full support.

*Chrome does not support subpixel values on border. Safari does not support subpixel values on box-shadow. Firefox supports subpixel values on both.

Horizontal and vertical centering

Horizontally and vertically centers a child element within a parent element.

HTML

<div class="horizontal-and-vertical-centering"> 
  <div class="child"></div> 
</div>

CSS

.horizontal-and-vertical-centering { 
  display: flex; 
  justify-content: center; 
  align-items: center; 
}

Demo

Explanation

display: flex enables flexbox.
justify-content: center centers the child horizontally.
align-items: center centers the child vertically.

Browser support

⚠️ Needs prefixes for full support.

https://caniuse.com/#feat=flexbox

Mouse cursor gradient tracking

A hover effect where the gradient follows the mouse cursor.

HTML

<button class="mouse-cursor-gradient-tracking"> 
  <span>Hover me</span> 
</button>

CSS

.mouse-cursor-gradient-tracking { 
  position: relative; 
  background: #2379f7; 
  padding: 0.5rem 1rem; 
  font-size: 1.2rem; 
  border: none; 
  color: white; 
  cursor: pointer; 
  outline: none; 
  overflow: hidden; 
} 
.mouse-cursor-gradient-tracking span { 
  position: relative; 
} 
.mouse-cursor-gradient-tracking::before { 
  --size: 0; 
  content: ''; 
  position: absolute; 
  left: var(--x); 
  top: var(--y); 
  width: var(--size); 
  height: var(--size); 
  background: radial-gradient(circle closest-side, pink, transparent); 
  transform: translate(-50%, -50%); 
  transition: width .2s ease, height .2s ease; 
} 
.mouse-cursor-gradient-tracking:hover::before { 
  --size: 200px; 
}

JavaScript

var btn = document.querySelector('.mouse-cursor-gradient-tracking') 
btn.onmousemove = function (e) { 
  var x = e.pageX - btn.offsetLeft 
  var y = e.pageY - btn.offsetTop 
  btn.style.setProperty('--x', x + 'px') 
  btn.style.setProperty('--y', y + 'px') 
}

Demo

Explanation

TODO

Note!

If the element’s parent has a positioning context (position: relative), you will need to subtract its offsets as well.

var x = e.pageX - btn.offsetLeft - btn.offsetParent.offsetLeft 
var y = e.pageY - btn.offsetTop - btn.offsetParent.offsetTop

Browser support

Requires JavaScript

⚠️ Requires JavaScript.

https://caniuse.com/#feat=css-variables

Overflow scroll gradient

Adds a fading gradient to an overflowing element to better indicate there is more content to be scrolled.

HTML

<div class="overflow-scroll-gradient"> 
  <div class="overflow-scroll-gradient__scroller"> 
    Content to be scrolled 
  </div> 
</div>

CSS

.overflow-scroll-gradient { 
  position: relative; 
} 
.overflow-scroll-gradient::after { 
  content: ''; 
  position: absolute; 
  bottom: 0; 
  width: 300px; 
  height: 25px; 
  background: linear-gradient(rgba(255, 255, 255, 0.001), white);  
} 
.overflow-scroll-gradient__scroller { 
  overflow-y: scroll; 
  background: white; 
  width: 300px; 
  height: 250px; 
  padding: 15px 0; 
  line-height: 1.2; 
  text-align: center; 
}

Demo

Explanation

position: relative on the parent establishes a Cartesian positioning context for psuedo elements.
::after defines a pseudo element.
background-image: linear-gradient(...) adds a linear gradient that fades from transparent to white (top to bottom).
position: absolute takes the pseudo element out of the flow of the document and positions it in relation to the parent.
width: 300px matches the size of the scrolling element (which is a child of the parent that has the pseudo element).
height: 25px is the height of the fading gradient psuedo element, which should be kept relatively small.
bottom: 0 positions the pseudo element at the bottom of the parent.

Browser support

✅ No caveats.

https://caniuse.com/#feat=css-gradients

Popout menu

Reveals an interactive popout menu on hover.

HTML

<div class="reference"> 
  <div class="popout-menu"> 
    Popout menu 
  </div> 
</div>

CSS

.reference { 
  position: relative; 
} 
.popout-menu { 
  position: absolute; 
  visibility: hidden; 
  left: 100%; 
} 
.reference:hover > .popout-menu { 
  visibility: visible; 
}

Demo

Explanation

position: relative on the reference parent establishes a Cartesian positioning context for its child.
position: absolute takes the popout menu out of the flow of the document and positions it in relation to the parent.
left: 100% moves the the popout menu 100% of its parent’s width from the left.
visibility: hidden hides the popout menu initially and allows for transitions (unlike display: none).
.reference:hover > .popout-menu means that when .reference is hovered over, select immediate children with a class of .popout-menu and change their visibility to visible, which shows the popout.

Browser support

✅ No caveats.

Pretty text underline

A nicer alternative to text-decoration: underline where descenders do not clip the underline. Natively implemented as text-decoration-skip-ink: auto but it has less control over the underline.

HTML

<p class="pretty-text-underline">Pretty text underline without clipping descending letters.</p>

CSS

.pretty-text-underline { 
  display: inline; 
  font-size: 1.25rem; 
  text-shadow: 1px 1px 0 #f5f6f9, 
    -1px 1px 0 #f5f6f9, 
    -1px -1px 0 #f5f6f9, 
    1px -1px 0 #f5f6f9; 
  background-image: linear-gradient(90deg, currentColor 100%, transparent 100%); 
  background-position: 0 1.04em; 
  background-repeat: repeat-x; 
  background-size: 1px 1px; 
} 
.pretty-text-underline::selection { 
  background-color: rgba(0, 150, 255, 0.3); 
  text-shadow: none; 
}

Demo

Pretty text underline without clipping descending letters.

Explanation

text-shadow: ... has 4 values with offsets that cover a 4×4 px area to ensure the underline has a “thick” shadow that covers the line where descenders clip it. Use a color that matches the background. For a larger font, use a larger px size.
background-image: linear-gradient(...) creates a 90deg gradient with the current text color (currentColor).
The background-* properties size the gradient as 1x1px at the bottom and repeats it along the x-axis.
The ::selection pseudo selector ensures the text shadow does not interfere with text selection.

Browser support

✅ No caveats.

Shape separator

Uses an SVG shape to separate two different blocks to create more a interesting visual appearance compared to standard horizontal separation.

HTML

<div class="shape-separator"></div>

CSS

.shape-separator { 
  position: relative; 
  height: 48px; 
} 
.shape-separator::after { 
  content: ''; 
  background-image: url(data:image/svg+xml;base64,PHN2ZyB2aWV3Qm94PSIwIDAgMjQgMjQiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgZmlsbC1ydWxlPSJldmVub2RkIiBjbGlwLXJ1bGU9ImV2ZW5vZGQiIHN0cm9rZS1saW5lam9pbj0icm91bmQiIHN0cm9rZS1taXRlcmxpbWl0PSIxLjQxNCI+PHBhdGggZD0iTTEyIDEybDEyIDEySDBsMTItMTJ6IiBmaWxsPSIjZmZmIi8+PC9zdmc+); 
  position: absolute; 
  width: 100%; 
  height: 24px; 
  bottom: 0; 
}

Demo

Explanation

position: relative on the element establishes a Cartesian positioning context for psuedo elements.
::after defines a pseudo element.
background-image: url(...) adds the SVG shape (a 24×24 triangle in base64 format) as the background image of the psuedo element, which repeats by default. It must be the same color as the block that is being separated.
position: absolute takes the pseudo element out of the flow of the document and positions it in relation to the parent.
width: 100% ensures the element stretches the entire width of its parent.
height: 24px is the same height as the shape.
bottom: 0 positions the pseudo element at the bottom of the parent.

Browser support

✅ No caveats.

https://caniuse.com/#feat=svg

System font stack

Uses the native font of the operating system to get close to a native app feel.

HTML

<p class="system-font-stack">This text uses the system font.</p>

CSS

.system-font-stack { 
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", Helvetica, Arial, sans-serif; 
}

Demo

This text uses the system font.

Explanation

The browser looks for each successive font, preferring the first one if possible, and falls back to the next if it cannot find the font (on the system or defined in CSS).

-apple-system is San Francisco, used on iOS and macOS (not Chrome however)
BlinkMacSystemFont is San Francisco, used on macOS Chrome
Segoe UI is used on Windows 10
Roboto is used on Android
Oxygen-Sans is used on GNU+Linux
Ubuntu is used on Linux
"Helvetica Neue" and Helvetica is used on macOS 10.10 and below (wrapped in quotes because it has a space)
Arial is a font widely supported by all operating systems
sans-serif is the fallback sans-serif font if none of the other fonts are supported

Browser support

✅ No caveats.

Triangle

Creates a triangle shape with pure CSS.

HTML

<div class="triangle"></div>

CSS

.triangle { 
  width: 0; 
  height: 0; 
  border-top: 20px solid #333; 
  border-left: 20px solid transparent; 
  border-right: 20px solid transparent; 
}

Demo

Explanation

View this link for a detailed explanation.

The color of the border is the color of the triangle. The side the triangle tip points corresponds to the opposite border-* property. For example, a color on border-top means the arrow points downward.

Experiment with the px values to change the proportion of the triangle.

Browser support

✅ No caveats.

Truncate text

If the text is longer than one line, it will be truncated and end with an ellipsis ....

HTML

<p class="truncate-text">If I exceed one line's width, I will be truncated.</p>

CSS

.truncate-text { 
  overflow: hidden; 
  white-space: nowrap; 
  text-overflow: ellipsis; 
}

Demo

This text will be truncated if it exceeds 200px in width.

Explanation

overflow: hidden prevents the text from overflowing its dimensions (for a block, 100% width and auto height).
white-space: nowrap prevents the text from exceeding one line in height.
text-overflow: ellipsis makes it so that if the text exceeds its dimensions, it will end with an ellipsis.

Browser support

✅ No caveats.

https://caniuse.com/#feat=text-overflow

https://atomiks.github.io/30-seconds-of-css/

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