CSS - backdrop-filter

Example

<div class="container">
  <div class="box">
    <p>backdrop-filter: blur(5px)</p>
  </div>
</div>

.box {
  background-color: rgba(255, 255, 255, 0.95);
  border-radius: 5px;
  font-family: sans-serif;
  text-align: center;
  line-height: 1; 
  backdrop-filter: blur(5px);
  max-width: 50%;
  max-height: 50%;
}

html,
body {
  height: 100%;
  width: 100%;
}

body {
  background-image: url('https://pixabay.com/static/uploads/photo/2014/08/26/20/06/lonely-428380_960_720.jpg');
  background-position: center center;
  background-repeat: no-repeat;
  background-size: cover;
}

.container {
  align-items: center;
  display: flex;
  justify-content: center;
  height: 100%;
  width: 100%;
}

Syntax  

/* Keyword value */
backdrop-filter: none;

/* URL to SVG filter */
backdrop-filter: url(commonfilters.svg#filter);

/* Filter functions */
backdrop-filter: blur(2px);
backdrop-filter: brightness(60%);
backdrop-filter: contrast(40%);
backdrop-filter: drop-shadow(4px 4px 10px blue);
backdrop-filter: grayscale(30%);
backdrop-filter: hue-rotate(120deg);
backdrop-filter: invert(70%);
backdrop-filter: opacity(20%);
backdrop-filter: sepia(90%);
backdrop-filter: saturate(80%);

/* Multiple filters */
backdrop-filter: url(filters.svg#filter) blur(4px) saturate(150%);

/* Global values */
backdrop-filter: inherit;
backdrop-filter: initial;
backdrop-filter: unset;

Values

none

Keyword indicating that no filter is applied to the backdrop.

<filter-function-list>

Space-separated list of filter functions, which will be applied to the backdrop. The different filter functions are the same as for the filter property.

Formal syntax

none | <filter-function-list>
where 
<filter-function-list> = [ <filter-function> | <url> ]+
where 
<filter-function> = <blur()> | <brightness()> | <contrast()> | <drop-shadow()> | <grayscale()> | <hue-rotate()> | <invert()> | <opacity()> | <sepia()> | <saturate()>
where 
<blur()> = blur( <length> )
<brightness()> = brightness( [ <number> | <percentage> ] )
<contrast()> = contrast( [ <number> | <percentage> ] )
<drop-shadow()> = drop-shadow( <length>{2,3} <color>? )
<grayscale()> = grayscale( [ <number> | <percentage> ] )
<hue-rotate()> = hue-rotate( <angle> )
<invert()> = invert( [ <number> | <percentage> ] )
<opacity()> = opacity( [ <number> | <percentage> ] )
<sepia()> = sepia( [ <number> | <percentage> ] )
<saturate()> = saturate( [ <number> | <percentage> ] )
where 
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
where 
<rgb()> = rgb( <rgb-component>#{3} )
<rgba()> = rgba( <rgb-component>#{3} , <alpha-value> )
<hsl()> = hsl( <hue>, <percentage>, <percentage> )
<hsla()> = hsla( <hue>, <percentage>, <percentage>, <alpha-value> )
<named-color> = <ident>
<deprecated-system-color> = ActiveBorder | ActiveCaption | AppWorkspace | Background | ButtonFace | ButtonHighlight | ButtonShadow | ButtonText | CaptionText | GrayText | Highlight | HighlightText | InactiveBorder | InactiveCaption | InactiveCaptionText | InfoBackground | InfoText | Menu | MenuText | Scrollbar | ThreeDDarkShadow | ThreeDFace | ThreeDHighlight | ThreeDLightShadow | ThreeDShadow | Window | WindowFrame | WindowText
where 
<rgb-component> = <integer> | <percentage>
<alpha-value> = <number>
<hue> = <number>

Description  

The backdrop-filter property provides for effects like blurring or color shifting the area behind an element, which can then be seen through that element by adjusting the element's transparency/opacity.

Browser Compatibility  

[1] Chrome currently doesn't implement this feature. See Chromium bug #497522.

[2] Gecko currently doesn't implement this feature. See bug 1178765.

See Also  

• filter
• Blog post by Dom Neill with examples
• Building iOS-like transparency effects in CSS with backdrop-filter

Specifications  

License