twbs--bootstrap/scss/_navbar.scss

// Wrapper and base class
//
// Provide a static navbar from which we expand to create full-width, fixed, and
// other navbar variations.

.navbar {
  position: relative;
  padding: $navbar-padding-y $navbar-padding-x;
  @include clearfix;

  @include media-breakpoint-up(sm) {
    @include border-radius($navbar-border-radius);
  }
}


// Navbar alignment options
//
// Display the navbar across the entirety of the page or fixed it to the top or
// bottom of the page.

// A static, full width modifier with no rounded corners.
.navbar-full {
  z-index: $zindex-navbar;

  @include media-breakpoint-up(sm) {
    @include border-radius(0);
  }
}

// Fix the top/bottom navbars when screen real estate supports it
.navbar-fixed-top,
.navbar-fixed-bottom {
  position: fixed;
  right: 0;
  left: 0;
  z-index: $zindex-navbar-fixed;

  // Undo the rounded corners
  @include media-breakpoint-up(sm) {
    @include border-radius(0);
  }
}

.navbar-fixed-top {
  top: 0;
}

.navbar-fixed-bottom {
  bottom: 0;
}

.navbar-sticky-top {
  position: sticky;
  top: 0;
  z-index: $zindex-navbar-sticky;
  width: 100%;

  // Undo the rounded corners
  @include media-breakpoint-up(sm) {
    @include border-radius(0);
  }
}


//
// Brand/project name
//

.navbar-brand {
  float: left;
  padding-top:    $navbar-brand-padding-y;
  padding-bottom: $navbar-brand-padding-y;
  margin-right: 1rem;
  font-size: $font-size-lg;

  @include hover-focus {
    text-decoration: none;
  }

  > img {
    display: block;
  }
}


.navbar-divider {
  float: left;
  width: $border-width;
  padding-top: .425rem;
  padding-bottom: .425rem;
  margin-right: $navbar-padding-x;
  margin-left:  $navbar-padding-x;
  overflow: hidden;

  &::before {
    content: "\00a0";
  }
}


// Navbar toggle
//
// Custom button for toggling the `.navbar-collapse`, powered by the collapse
// Bootstrap JavaScript plugin.

.navbar-toggler {
  padding: .5rem .75rem;
  font-size: $font-size-lg;
  line-height: 1;
  background: none;
  border: $border-width solid transparent;
  @include border-radius($btn-border-radius);

  @include hover-focus {
    text-decoration: none;
  }
}

// Navigation
//
// Custom navbar navigation built on the base `.nav` styles.

.navbar-nav {
  .nav-item {
    float: left;
  }

  .nav-link {
    display: block;
    padding-top:    .425rem;
    padding-bottom: .425rem;

    + .nav-link {
      margin-left: 1rem;
    }
  }

  .nav-item + .nav-item {
    margin-left: 1rem;
  }
}

// Dark links against a light background
.navbar-light {
  .navbar-brand {
    color: $navbar-light-active-color;

    @include hover-focus {
      color: $navbar-light-active-color;
    }
  }

  .navbar-nav {
    .nav-link {
      color: $navbar-light-color;

      @include hover-focus {
        color: $navbar-light-hover-color;
      }
    }

    .open > .nav-link,
    .active > .nav-link,
    .nav-link.open,
    .nav-link.active {
      @include plain-hover-focus {
        color: $navbar-light-active-color;
      }
    }
  }

  .navbar-divider {
    background-color: rgba(0,0,0,.075);
  }
}

// White links against a dark background
.navbar-dark {
  .navbar-brand {
    color: $navbar-dark-active-color;

    @include hover-focus {
      color: $navbar-dark-active-color;
    }
  }

  .navbar-nav {
    .nav-link {
      color: $navbar-dark-color;

      @include hover-focus {
        color: $navbar-dark-hover-color;
      }
    }

    .open > .nav-link,
    .active > .nav-link,
    .nav-link.open,
    .nav-link.active {
      @include plain-hover-focus {
        color: $navbar-dark-active-color;
      }
    }
  }

  .navbar-divider {
    background-color: rgba(255,255,255,.075);
  }
}


// Navbar toggleable
//
// Custom override for collapse plugin in navbar.

.navbar-toggleable {
  &-xs {
    @include clearfix;
    @include media-breakpoint-down(xs) {
      .navbar-nav .nav-item {
        float: none;
        margin-left: 0;
      }
    }
    @include media-breakpoint-up(sm) {
      display: block !important;
    }
  }

  &-sm {
    @include clearfix;
    @include media-breakpoint-down(sm) {
      .navbar-nav .nav-item {
        float: none;
        margin-left: 0;
      }
    }
    @include media-breakpoint-up(md) {
      display: block !important;
    }
  }

  &-md {
    @include clearfix;
    @include media-breakpoint-down(md) {
      .navbar-nav .nav-item {
        float: none;
        margin-left: 0;
      }
    }
    @include media-breakpoint-up(lg) {
      display: block !important;
    }
  }
}