mkdocs-material/src/assets/stylesheets/main/layout/_tooltip.scss

////
/// Copyright (c) 2016-2021 Martin Donath <martin.donath@squidfunk.com>
///
/// Permission is hereby granted, free of charge, to any person obtaining a
/// copy of this software and associated documentation files (the "Software"),
/// to deal in the Software without restriction, including without limitation
/// the rights to use, copy, modify, merge, publish, distribute, sublicense,
/// and/or sell copies of the Software, and to permit persons to whom the
/// Software is furnished to do so, subject to the following conditions:
///
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
///
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
/// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
/// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
/// DEALINGS
////

// ----------------------------------------------------------------------------
// Keyframes
// ----------------------------------------------------------------------------

// Continuous pulse animation
@keyframes pulse {
  0% {
    box-shadow: 0 0 0 0 var(--md-default-fg-color--lightest);
  }

  75% {
    box-shadow: 0 0 0 px2em(10px) transparent;
  }

  100% {
    box-shadow: 0 0 0 0 transparent;
  }
}

// ----------------------------------------------------------------------------
// Rules
// ----------------------------------------------------------------------------

// Tooltip variables
:root {
  --md-tooltip-width: #{px2rem(400px)};
}

// ----------------------------------------------------------------------------

// Tooltip
.md-tooltip {
  position: absolute;
  top: var(--md-tooltip-y);
  left:
    clamp(
      calc(
        var(--md-tooltip-0, #{px2rem(0px)}) +
        #{px2rem(16px)}
      ),
      var(--md-tooltip-x),
      calc(
        100vw -
        var(--md-tooltip-width) +
        calc(
          var(--md-tooltip-0, #{px2rem(0px)}) +
          #{px2rem(16px)}
        ) -
        2 * #{px2rem(16px)}
      )
    );
  // Hack: set an explicit `z-index` so we can transition it to ensure that any
  // following elements are not overlaying the tooltip during the transition.
  z-index: 0;
  width: var(--md-tooltip-width);
  max-width: calc(100vw - 2 * #{px2rem(16px)});
  max-height: 0;
  color: var(--md-default-fg-color);
  background-color: var(--md-default-bg-color);
  border-radius: px2rem(2px);
  box-shadow: var(--md-shadow-z2);
  transform: translateY(px2rem(-8px));
  // Hack: promote to own layer to reduce jitter
  backface-visibility: hidden;
  opacity: 0;
  transition:
    transform    0ms 250ms,
    opacity    250ms,
    max-height   0ms 250ms,
    z-index    250ms;

  // [reduced-motion]: Disable animation
  @media (prefers-reduced-motion) {
    transition: none;
  }

  // Tooltip on parent focus
  :focus-within > & {
    max-height: 1000%;
    transform: translateY(0);
    opacity: 1;
    transition:
      transform  250ms cubic-bezier(0.1, 0.7, 0.1, 1),
      opacity    250ms,
      max-height 250ms,
      z-index      0ms;

    // [reduced-motion]: Disable animation
    @media (prefers-reduced-motion) {
      transition: none;
    }
  }

  // Show outline for keyboard devices
  .focus-visible > & {
    outline: var(--md-accent-fg-color) auto;
  }

  // Tooltip wrapper
  &__inner {
    padding: px2rem(16px);
    font-size: px2rem(12.8px);

    // Adjust spacing on first child
    &.md-typeset > :first-child {
      margin-top: 0;
    }

    // Adjust spacing on last child
    &.md-typeset > :last-child {
      margin-bottom: 0;
    }
  }
}

// ----------------------------------------------------------------------------

// Annotation
.md-annotation {
  white-space: normal;
  outline: none;

  // Annotation is not hidden (e.g. when copying)
  &:not([hidden]) {
    display: inline-block;
  }

  // Promote children to top on focus
  &:focus-within > * {
    z-index: 2;
  }

  // Annotation wrapper (= tooltip)
  &__inner {
    top: calc(var(--md-tooltip-y) + 1.2ch);
    font-family: var(--md-text-font-family);

    // Annotation tooltip when not focused
    :not(:focus-within) > & {
      user-select: none;
      pointer-events: none;
    }
  }

  // Annotation index
  &__index {
    position: relative;
    z-index: 0;
    margin: 0 1ch;
    color: hsla(0, 0%, 100%, 1);
    cursor: pointer;
    transition: z-index 250ms;
    user-select: none;

    // Annotation marker – the marker must be positioned absolutely behind
    // the index, because it shouldn't impact the rendering of a code block.
    // Otherwise, small rounding differences in browsers can sometimes mess up
    // alignment of text following a Annotation.
    &::after {
      position: absolute;
      top: 0.025em;
      left: -0.126em;
      z-index: -1;
      width: max(2.2ch, 100% + 1.2ch);
      height: 2.2ch;
      margin: 0 -0.4ch;
      padding: 0 0.4ch;
      background-color: var(--md-default-fg-color--lighter);
      border-radius: 2ch;
      transition:
        color            250ms,
        background-color 250ms;
      animation: pulse 2000ms infinite;
      content: "";

      // [reduced-motion]: Disable animation
      @media (prefers-reduced-motion) {
        transition: none;
        animation: none;
      }

      // Annotation marker on focus/hover
      :is(:focus-within, :hover) > & {
        background-color: var(--md-accent-fg-color);
      }

      // Annotation marker on focus
      :focus-within > & {
        transition:
          color            250ms,
          background-color 250ms;
        animation: none;

        // [reduced-motion]: Disable animation
        @media (prefers-reduced-motion) {
          transition: none;
        }
      }
    }

    // Annotation index on focus/hover
    :is(:focus-within, :hover) > & {
      color: var(--md-accent-bg-color);
    }

    // Annotation index on focus
    :focus-within > & {
      transition: none;
      animation: none;
    }
  }
}