tabler/scss/layout/_layout.scss

/**
Layout
 */

@mixin menu-side {
  align-items: flex-start;
}

@mixin menu-collapsed {
  .layout-area-menu {
    position: fixed;
    left: -($sidenav-width);
    top: 0;
    bottom: 0;
    background: $dark;
    color: $white;
    width: $sidenav-width;
    z-index: $zindex-fixed;
    transition: .3s left;

    @include menu-side;
  }

  .layout-area-menu-backdrop {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: 100vw;
    background: rgba($dark, .1);
    z-index: $zindex-fixed - 1;
    visibility: hidden;
    opacity: 0;
  }

  @at-root body.menu-visible & {
    .layout-area-menu {
      left: 0;
    }

    .layout-area-menu-backdrop {
      opacity: 1;
      visibility: visible;
    }
  }
}

.layout {
  position: relative;
  display: grid;

  grid-template:
    "head" auto
    "menu" auto
    "main" auto /
    100%;
}

.layout-collapsed {
  @each $breakpoint in map-keys($grid-breakpoints) {
    $infix: breakpoint-infix($breakpoint);

    @if $infix != '' {
      @include media-breakpoint-down($breakpoint) {

        &#{$infix} {
          @include menu-collapsed;
        }
      }
    } @else {
      @include menu-collapsed;
    }
  }
}

.layout-sidebar {
  @each $breakpoint in map-keys($grid-breakpoints) {
    $infix: breakpoint-infix($breakpoint);

    @include media-breakpoint-up($breakpoint) {


      &#{$infix} {
        grid-template:
          "menu head" auto
          "menu main" auto /
          auto 1fr;

        .layout-area-menu {
          width: $sidenav-width;
        }
      }

      &-folded#{$infix} {
        grid-template:
          "menu head" auto
          "menu main" auto /
          auto 1fr;

        .layout-area-menu {
          width: $sidenav-folded-width;

        }
      }
    }
  }
}

.layout-area-topnav {
  grid-area: head;
}

.layout-area-menu {
  grid-area: menu;
}

.layout-area-menu-backdrop {
  display: none;
}

.layout-area-main {
  grid-area: main;
}