src/templates/assets/stylesheets/main/components/_tabs.scss
////
/// Copyright (c) 2016-2025 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
////

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

// Navigation tabs
.md-tabs {
  // Must be higher than the z-index of the back-to-top button, or the button
  // will overlay the navigation tabs bar when scrolling up fast.
  z-index: 3;
  display: block;
  width: 100%;
  overflow: auto;
  line-height: 1.3;
  color: var(--md-primary-bg-color);
  background-color: var(--md-primary-fg-color);

  // [print]: Hide tabs
  @media print {
    display: none;
  }

  // [tablet -]: Hide tabs
  @include break-to-device(tablet) {
    display: none;
  }

  // Navigation tabs are hidden
  &[hidden] {
    pointer-events: none;
  }

  // Navigation tabs list
  &__list {
    display: flex;
    padding: 0;
    margin: 0;
    margin-inline-start: px2rem(4px);
    overflow: auto;
    white-space: nowrap;
    list-style: none;
    contain: content;
    // Hack: don't show scrollbar when navigation tabs overflow, which should
    // only happen in rare occasions, as adding too many top level sections is
    // discouraged, since hiding content on horitontal axis doesn't lead to a
    // good user experience. It's just harder to discover.
    scrollbar-width: none;

    // Hack: see above
    &::-webkit-scrollbar {
      display: none;
    }
  }

  // Navigation tabs item
  &__item {
    height: px2rem(48px);
    padding-inline: px2rem(12px);

    // Navigation tabs link in active navigation
    &--active .md-tabs__link {
      color: inherit;
      opacity: 1;
    }
  }

  // Navigation tabs link - could be defined as block elements and aligned via
  // line height, but this would imply more repaints when scrolling
  &__link {
    display: flex;
    margin-top: px2rem(16px);
    font-size: px2rem(14px);
    outline-color: var(--md-accent-fg-color);
    outline-offset: px2rem(4px);
    // Hack: save a repaint when tabs are appearing on scrolling up
    backface-visibility: hidden;
    opacity: 0.7;
    transition:
      transform 400ms cubic-bezier(0.1, 0.7, 0.1, 1),
      opacity   250ms;

    // Navigation tabs link on focus/hover
    &:is(:focus, :hover) {
      color: inherit;
      opacity: 1;
    }

    // Navigation tabs link icon
    svg {
      height: 1.3em;
      margin-inline-end: px2rem(8px);
      fill: currentcolor;
    }

    // Delay transitions by a small amount
    @for $i from 2 through 16 {
      .md-tabs__item:nth-child(#{$i}) & {
        transition-delay: 20ms * ($i - 1);
      }
    }

    // Hide tabs upon scrolling - disable transition to minimizes repaints
    // while scrolling down, while scrolling up seems to be okay
    .md-tabs[hidden] & {
      opacity: 0;
      transition:
        transform 0ms 100ms,
        opacity 100ms;
      transform: translateY(50%);
    }
  }
}
