devdocs/assets/stylesheets/components/_settings.scss

//
// Settings
//

._settings {
  display: none;
  position: absolute;
  top: 0;
  bottom: 0;
  z-index: $headerZ;

  &._in { display: block; }

  ._sidebar {
    &:after { // padding bottom
      content: '';
      display: block;
      height: $headerHeight;
    }

    ._sidebar-hidden & { display: block; }
  }

  ._header { justify-content: space-between; }
}

//
// Settings page
//

._settings-fieldset {
  display: flex;
  margin: 1.5rem 0;
  line-height: 1.5rem;
}

._settings-legend {
  flex: 0 1 10rem;
  margin: 0;
  padding-right: .5rem;
  line-height: inherit;
  font-size: inherit;
  font-weight: $boldFontWeight;
  text-align: right;
  @extend %border-box;
}

._settings-inputs {
  flex: 1 1 20rem;
}

._settings-label {
  margin: 0 0 .375rem;

  > small {
    display: block;
    color: $textColorLight;
    margin-left: 1.75rem;
  }

  input[type=checkbox] {
    display: inline-block;
    vertical-align: top;
    margin: .25rem .375rem;
  }
}

@media (max-width: $maxWidth) {
  ._setting-max-width { display: none; }
}

._reset-link {
  color: $textColorRed;
}

//
// Footer
//

._sidebar-footer {
  position: fixed;
  z-index: $headerZ;
  bottom: 0;
  left: 0;
  width: $sidebarWidth;
  height: $headerHeight;
  background: $noteGreenBackground;
  border-top: 1px solid $noteGreenBorder;
  border-right: 1px solid $noteGreenBorder;
  @extend %border-box;
  @extend %user-select-none;

  @media #{$mediumScreen} { width: $sidebarMediumWidth; }
}

._settings-btn {
  display: block;
  width: 100%;
  height: 100%;
  line-height: 1.5rem;
  padding: 0 .75rem;
  font-size: .875rem;
  font-weight: $boldFontWeight;
  color: inherit;
  text-align: left;
  cursor: pointer;
  @extend %border-box;

  > svg {
    display: inline-block;
    vertical-align: top;
    width: 1.5rem;
    height: 1.5rem;
    margin-right: .125rem;
    fill: currentColor;
    pointer-events: none;
  }
}

//
// Header tabs
//

._settings-tabs {
  display: none; // mobile only
  margin-right: .5rem;
  line-height: $headerHeight;
}

._settings-tab {
  position: relative;
  display: inline-block;
  vertical-align: top;
  padding: 0 .75rem;
  cursor: pointer;

  &, &:hover {
    color: $textColorLight;
    text-decoration: none;
  }

  &.active {
    color: $textColor;
    font-weight: $boldFontWeight;
    text-decoration: none;
    box-shadow: inset 0 -2px $linkColor;
  }
}