mkdocs-material/src/assets/stylesheets/layout/_sidebar.scss

////
/// Copyright (c) 2016-2017 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
////

// ----------------------------------------------------------------------------
// Variables
// ----------------------------------------------------------------------------

// Active (toggled) drawer
$md-toggle__drawer--checked:
  "[data-md-toggle=\"drawer\"]:checked ~ .md-container";

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

// Sidebar container
.md-sidebar {
  position: absolute;
  width: 24.2rem;
  padding: 2.4rem 0;
  overflow: hidden;

  // Hide for print
  @media print {
    display: none;
  }

  // Lock sidebar to container height (account for fixed header)
  &[data-md-state="lock"] {
    position: fixed;
    top: 4.8rem;
  }

  // [tablet -]: Convert navigation to drawer
  @include break-to-device(tablet) {

    // Render primary sidebar as a slideout container
    &--primary {
      position: fixed;
      top: 0;
      left: -24.2rem;
      width: 24.2rem;
      height: 100%;
      transform: translateX(0);
      transition:
        transform  0.25s cubic-bezier(0.4, 0, 0.2, 1),
        box-shadow 0.25s;
      background-color: $md-color-white;
      z-index: 3;

      // Just hide drawer, if browser doesn't support 3D transforms
      .no-csstransforms3d & {
        display: none;
      }

      // Expanded drawer
      #{$md-toggle__drawer--checked} & {
        @include z-depth(8);

        transform: translateX(24.2rem);

        // Just show drawer, if browser doesn't support 3D transforms
        .no-csstransforms3d & {
          display: block;
        }
      }

      // Hide overflow for nested navigation
      .md-sidebar__scrollwrap {
        overflow: hidden;
      }
    }
  }

  // Secondary sidebar with table of contents
  &--secondary {
    display: none;

    // [tablet landscape +]: Show table of contents next to body copy
    @include break-from-device(tablet landscape) {
      display: block;
      margin-left: 100%;
      transform: translate(-100%, 0);
    }

    // [screen +]: Limit to grid
    @include break-from-device(screen) {
      margin-left: 122rem;
    }
  }

  // Wrapper for scrolling on overflow
  &__scrollwrap {
    max-height: 100%;
    margin: 0 0.4rem;
    overflow-y: auto;
    // Hack: putting the scroll wrapper on the GPU massively reduces jitter
    // when locking the sidebars into place
    backface-visibility: hidden;

    // [tablet -]: Adjust margins
    @include break-to-device(tablet) {

      // Stretch scrollwrap for primary sidebar
      .md-sidebar--primary & {
        position: absolute;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;
        margin: 0;
      }
    }

    // Override native scrollbar styles
    &::-webkit-scrollbar {
      width: 0.4rem;
      height: 0.4rem;
    }

    // Style scrollbar thumb
    &::-webkit-scrollbar-thumb {
      background-color: $md-color-black--lighter;

      // Hovered scrollbar thumb
      &:hover {
        background-color: $md-color-accent;
      }
    }
  }

  // Sidebar content
  &__inner {

    // [screen +]: Add line for reference
    @include break-from-device(screen) {
      border-right: 0.1rem solid $md-color-black--lightest;
    }
  }
}