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;
  @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.

// Static top (unfixed, but 100% wide) navbar
.navbar-static-top {
  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;
  margin-bottom: 0; // override .navbar defaults

  // 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: .95rem 1rem;
  font-size: $font-size-lg;
  line-height: 1;
  color: $navbar-default-brand-color;

  @include hover-focus {
    color: $navbar-default-brand-hover-color;
    text-decoration: none;
  }

  > img {
    display: block;
  }
}


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

.navbar-toggler {
  padding: .5rem .75rem;
  margin-top: .375rem;
  margin-bottom: .375rem;
  font-size: $font-size-lg;
  line-height: 1;
  color: $navbar-default-link-color;
  background: none;
  border: $border-width solid transparent;
  @include border-radius($btn-border-radius);

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

// Custom override for
.navbar-toggleable {
  &-xs {
    @include media-breakpoint-up(sm) {
      display: block !important;
    }
  }
  &-sm {
    @include media-breakpoint-up(md) {
      display: block !important;
    }
  }
}


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

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

  .nav-link {
    display: block;
    padding: .95rem .75rem;
    line-height: 1.25; // Match the `.navbar-brand`
    color: $navbar-default-link-color;

    @include hover-focus {
      color: $navbar-default-link-hover-color;
      background-color: $navbar-default-link-hover-bg;
    }
  }

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


// Forms
//
// Additional modifier class to add to `.form-inline` to vertically center forms.

.navbar-form {
  margin-top: .375rem;
  margin-bottom: .375rem;
  margin-right: 1rem;
}


//
// Alternate navbars
//

// todo: audit these styles

// Default navbar
.navbar-default {
  background-color: $navbar-default-bg;
  border-color: $navbar-default-border;

  .navbar-brand {
    color: $navbar-default-brand-color;

    @include hover-focus {
      color: $navbar-default-brand-hover-color;
      background-color: $navbar-default-brand-hover-bg;
    }
  }
}

// Inverse navbar

.navbar-inverse {
  background-color: $navbar-inverse-bg;
  border-color: $navbar-inverse-border;

  .navbar-brand {
    color: $navbar-inverse-brand-color;

    @include hover-focus {
      color: $navbar-inverse-brand-hover-color;
      background-color: $navbar-inverse-brand-hover-bg;
    }
  }

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

      @include hover-focus {
        color: $navbar-inverse-link-hover-color;
        background-color: $navbar-inverse-link-hover-bg;
      }
    }

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

  .navbar-toggler {
    color: $navbar-inverse-link-color;
  }
}