[CSS] Raise the Curtains

Raise the Curtains

転がる背景が暗から光に変わり、上の内容もsticky positionの場合、光から暗に変わる効果です.

HTMLとCSSのみで実現します.

HTML

<div class="curtain">
  <div class="invert">
    <h2>Curtain Effect</h2>
  </div>
</div>

Set up some CSS variables

css変数を作成し、必要に応じて簡単に変更できるように設定します.

:root {
  --minh: 98vh;
  --color1: wheat;
  --color2: midnightblue;
}

.Curtain Draw

A linear-gradient for the “split” background

min-height for the extra space at the bottom of the container

仮想要素(pseudo-element)を使用して、下部に余分なスペースを作成します.

.curtain {
  /** create the "split" background **/
  background-image: linear-gradient(to bottom, 
  					var(--color2) 50%, var(--color1) 50%);
}

/** add extra space to the bottom
(need this for the "sticky" effect) **/
.curtain::after {
  content: "";
  display: block;
  min-height: var(--minh);
}

Making sticky content

position: sticky and top define the stickiness and where it sticks.

mix-blend-mode: difference blends the color of the content inside the h2 element into the .curtain‘s background gradient.

display: flex centers the content for presentation.

min-height defines the height of the container and allows for the extra space at the bottom.

color sets the color of the h2 heading.

.invert {
  /** make the content sticky **/
  position: sticky;
  top: 20px;

  /** blend the content with the contrast effect **/
  mix-blend-mode: difference;

  /** center the content **/
  display: flex;
  align-items: center;
  justify-content: center;
  
  /** set the minimum height of the section **/
  min-height: var(--minh);
}

h2 {
  /** set the color of the text **/
  color: var(--color1);
}

mix-blend-mode: difference ?

これはCSSを用いてテキスト色を簡単に反転させる方法である.
値をdifference(difference)に設定すると、下敷き要素とは反対の色を表示できます.

コメントサイト

https://studiomeal.com/archives/888(CSSテキスト反転効果)

https://studiomeal.com/archives/852(CSSを使用して白黒画像を作成)

“Raise the Curtains” Demo

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REFERENCE

• https://css-tricks.com/css-raise-the-curtains-effect/