backdrop-filter

backdrop-filter: blur(10px);

backdrop-filter: invert(80%);

backdrop-filter: sepia(90%);

<section class="default-example" id="default-example">
  <div class="example-container">
    <div id="example-element">例</div>
  </div>
</section>

.example-container {
  background-image: url("/shared-assets/images/examples/balloon.jpg");
  background-size: cover;
  width: 200px;
  height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: black;
}

#example-element {
  font-weight: bold;
  flex: 1;
  text-align: center;
  padding: 20px 10px;
  background-color: rgb(255 255 255 / 0.2);
}

/* キーワード値 */
backdrop-filter: none;

/* SVG フィルターへの URL */
backdrop-filter: url("common-filters.svg#filter");

/* <filter-function> 値 */
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%);

/* 複数のフィルター */
backdrop-filter: url("filters.svg#filter") blur(4px) saturate(150%);

/* グローバル値 */
backdrop-filter: inherit;
backdrop-filter: initial;
backdrop-filter: revert;
backdrop-filter: revert-layer;
backdrop-filter: unset;

.box {
  background-color: rgb(255 255 255 / 30%);
  backdrop-filter: blur(10px);
}

body {
  background-image: url("anemones.jpg");
}

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

.container {
  background-size: cover;
  align-items: center;
  display: flex;
  justify-content: center;
  height: 100%;
  width: 100%;
}
.box {
  border-radius: 5px;
  font-family: sans-serif;
  text-align: center;
  max-width: 50%;
  max-height: 50%;
  padding: 20px 40px;
}

<div class="container">
  <div class="box">
    <p>backdrop-filter: blur(10px)</p>
  </div>
</div>