AdminLte/build/scss/_main-header.scss

//
// Component: Main Header
//
 
.main-header {
  border-bottom: $main-header-bottom-border;
  z-index: $zindex-main-header;

  .nav-link {
    height: $nav-link-height;
    position: relative;
  }

  .navbar-nav {
    .nav-item {
      margin: 0;
    }

    &[class*='-right'] {
      .dropdown-menu {
        left: auto;
        margin-top: -3px;
        right: 0;

        @media (max-width: breakpoint-max(xs)) {
          left: 0;
          right: auto;
        }
      }
    }
  }
}

// Add this class to images within a nav-link
.navbar-img {
  height: $main-header-height / 2;
  width: auto;
}

// Navbar badge
.navbar-badge {
  font-size: .6rem;
  font-weight: 300;
  padding: 2px 4px;
  position: absolute;
  right: 5px;
  top: 9px;
}

.btn-navbar {
  background-color: transparent;
  border-left-width: 0;
}

.form-control-navbar {
  border-right-width: 0;

  & + .input-group-append {
    margin-left: 0;
  }
}

.form-control-navbar,
.btn-navbar {
  transition: none;
}

.navbar-dark {
  .form-control-navbar,
  .btn-navbar {
    background-color: $main-header-dark-form-control-bg;
    border: $main-header-dark-form-control-border;
  }

  .form-control-navbar {
    &::placeholder,
    + .input-group-append > .btn-navbar {
      color: $main-header-dark-placeholder-color;
    }

    &:focus {
      &,
      & + .input-group-append .btn-navbar {
        background-color: $main-header-dark-form-control-focused-bg;
        border: $main-header-dark-form-control-focused-border !important;
        color: $main-header-dark-form-control-focused-color;
      }
    }
  }
}

.navbar-light {
  .form-control-navbar,
  .btn-navbar {
    background-color: $main-header-light-form-control-bg;
    border: $main-header-light-form-control-border;
  }

  .form-control-navbar {
    &:ms-placeholder,
    &:moz-placeholder,
    &::moz-placeholder,
    &::placeholder,
    + .input-group-append > .btn-navbar {
      color: $main-header-light-placeholder-color;
    }

    &:focus {
      &,
      & + .input-group-append .btn-navbar {
        background-color: $main-header-light-form-control-focused-bg;
        border: $main-header-light-form-control-focused-border !important;
        color: $main-header-light-form-control-focused-color;
      }
    }
  }
}