BookStack/resources/assets/sass/_layout.scss

/**
 * Generic content container
 */
.container {
  max-width: $xxl;
  margin-left: auto;
  margin-right: auto;
  padding-left: $-m;
  padding-right: $-m;
  &.small {
    max-width: 840px;
  }
  &.very-small {
    max-width: 480px;
  }
}

/**
 * Core grid layout system
 */
.grid {
  display: grid;
  grid-column-gap: $-l;
  grid-row-gap: $-l;
  &.half {
    grid-template-columns: 1fr 1fr;
  }
  &.third {
    grid-template-columns: 1fr 1fr 1fr;
  }
  &.left-focus {
    grid-template-columns: 2fr 1fr;
  }
  &.right-focus {
    grid-template-columns: 1fr 3fr;
  }
  &.gap-y-xs {
    grid-row-gap: $-xs;
  }
  &.gap-xl {
    grid-column-gap: $-xl;
    grid-row-gap: $-xl;
  }
  &.gap-xxl {
    grid-column-gap: $-xxl;
    grid-row-gap: $-xxl;
  }
  &.v-center {
    align-items: center;
  }
  &.no-gap {
    grid-row-gap: 0;
    grid-column-gap: 0;
  }
  &.no-row-gap {
    grid-row-gap: 0;
  }
}

@include smaller-than($m) {
  .grid.third {
    grid-template-columns: 1fr 1fr;
  }
  .grid.half:not(.no-break), .grid.left-focus:not(.no-break), .grid.right-focus:not(.no-break) {
    grid-template-columns: 1fr;
  }
  .grid.half.collapse-xs {
    grid-template-columns: 1fr 1fr;
  }
  .grid.gap-xl {
    grid-column-gap: $-m;
    grid-row-gap: $-m;
  }
  .grid.right-focus.reverse-collapse > *:nth-child(2) {
    order: 0;
  }
  .grid.right-focus.reverse-collapse > *:nth-child(1) {
    order: 1;
  }
}

@include smaller-than($s) {
  .grid.third {
    grid-template-columns: 1fr;
  }
}

@include smaller-than($xs) {
  .grid.half.collapse-xs {
    grid-template-columns: 1fr;
  }
}

/**
 * Flexbox layout system
 */
body.flexbox {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  height: 100%;
  min-height: 100%;
  max-height: 100%;
  overflow: hidden;
  #content {
    flex: 1;
    display: flex;
    min-height: 0;
  }
}

.flex-fill {
  display: flex;
  align-items: stretch;
  min-height: 0;
  max-width: 100%;
  position: relative;
}

.flex {
  min-height: 0;
  flex: 1;
}


/**
 * Display and float utilities
 */
.block {
  display: block;
  position: relative;
}

.inline {
  display: inline;
}

.block.inline {
  display: inline-block;
}

.float {
  float: left;
  &.right {
    float: right;
  }
}

/**
 * Visibility
 */
@each $sizeLetter, $size in $screen-sizes {
  @include smaller-than($size) {
    .hide-under-#{$sizeLetter} {
      display: none !important;
    }
  }
  @include larger-than($size) {
    .hide-over-#{$sizeLetter} {
      display: none !important;
    }
  }
}

/**
 * Inline content columns
 */
.dual-column-content {
  columns: 2;
}

@include smaller-than($m) {
  .dual-column-content {
    columns: 1;
  }
}


/**
 * Fixes
 */
.clearfix:before,
.clearfix:after {
  content: " ";
  display: table;
}
.clearfix:after {
  clear: both;
}

/**
 * View Layouts
 */
.tri-layout-container {
  display: grid;
  margin-left: $-xl;
  margin-right: $-xl;
  grid-template-columns: 1fr 4fr 1fr;
  grid-template-areas: "a b c";
  grid-column-gap: $-xxl;
  .tri-layout-right {
    grid-area: c;
    min-width: 0;
  }
  .tri-layout-left {
    grid-area: a;
    min-width: 0;
  }
  .tri-layout-middle {
    grid-area: b;
    padding-top: $-m;
  }
}
@include smaller-than($xxl) {
  .tri-layout-container {
    grid-template-areas:  "c b b"
    "a b b";
    grid-template-columns: 1fr 3fr;
    grid-template-rows: max-content min-content;
    padding-right: $-l;
  }
}
@include larger-than($xxl) {
  .tri-layout-left-contents, .tri-layout-right-contents {
    padding: $-m;
    position: sticky;
    top: $-m;
    max-height: 100vh;
    min-height: 50vh;
    overflow-y: scroll;
    overflow-x: hidden;
    scrollbar-width: none;
    -ms-overflow-style: none;
    &::-webkit-scrollbar {
      display: none;
    }
  }
  .tri-layout-middle-contents {
    max-width: 940px;
    margin: 0 auto;
  }
}

@include smaller-than($l) {
  .tri-layout-container {
    grid-template-areas:  none;
    grid-template-columns: 1fr;
    grid-column-gap: 0;
    padding-right: $-xs;
    padding-left: $-xs;
    .tri-layout-left-contents, .tri-layout-right-contents {
      padding-left: $-m;
      padding-right: $-m;
    }
    .tri-layout-right-contents > div, .tri-layout-left-contents > div {
      opacity: 0.6;
      z-index: 0;
    }
    .tri-layout-left > *, .tri-layout-right > * {
      display: none;
      pointer-events: none;
    }
    .tri-layout-left, .tri-layout-right {
      grid-area: none;
      grid-column: 1/1;
      grid-row: 1;
      padding-top: 0 !important;
    }
    .tri-layout-middle {
      grid-area: none;
      grid-row: 3;
      grid-column: 1/1;
      z-index: 1;
      overflow: hidden;
      transition: transform ease-in-out 240ms;
    }
    .tri-layout-left {
      grid-row: 2;
    }
    &.show-info {
      overflow: hidden;
      .tri-layout-middle {
        display: none;
      }
      .tri-layout-right  > *, .tri-layout-left > * {
        display: block;
        pointer-events: auto;
      }
    }
  }
}
@include larger-than($l) {
  .tri-layout-mobile-tabs {
    display: none;
  }
}

@include smaller-than($m) {
  .tri-layout-container {
    margin-left: 0;
    margin-right: 0;
  }
}

.tri-layout-left-contents > div, .tri-layout-right-contents > div {
  opacity: 0.6;
  transition: opacity ease-in-out 120ms;
  &:hover {
    opacity: 1;
  }
}