如何消除 .dropdown 和 .dropdown-menu 之间的间隙

在移动视图中时，单击.dropdown菜单之间有一个小空间.dropdown和.dropdown-menu.

如图所示

Question是否可以消除那个小空间/间隙？

Codepen 示例代码视图 http://codepen.io/riwakawebsitedesigns/pen/wWRVKv and 全视图 http://codepen.io/riwakawebsitedesigns/full/wWRVKv/

CSS

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    color: #fff;
    background: #222;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    margin: 0;
    color: #000000;
}

.row {
    margin-bottom: 20px;
}

.row:last-of-type {
    margin-bottom: 0;
}

.bg {
    background-color: #eeeeee;
    padding: 40px 40px 40px 40px;
}

#custom-bootstrap-menu {
    margin-top: 40px;
    margin-bottom: 0;
    border-color: 0;
}

#custom-bootstrap-menu .navbar-brand {
    color: rgba(255, 255, 255, 1);
}

#custom-bootstrap-menu {
    font-size: 14px;
    background-color: rgba(51, 51, 51, 1);
    border-width: 0px;
    border-radius: 0px;
}

#custom-bootstrap-menu .navbar-nav > li > a {
    color: #ffffff;
}

@media (min-width: 768px) {
    #custom-bootstrap-menu .navbar-nav > li > a.link1 {
        border-top: 3px solid #e18728;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link1:hover,
    #custom-bootstrap-menu .navbar-nav > li > a.link1:focus {
        color: #ffffff;
        background-color: #e18728;
    }

    #custom-bootstrap-menu .navbar-nav > li.active > a.link1 {
        color: #ffffff;
        background-color: #e18728;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link2 {
        border-top: 3px solid #BE4C39;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link2:hover,
    #custom-bootstrap-menu .navbar-nav > li > a.link2:focus {
        color: #ffffff;
        background-color: #BE4C39;
    }

    #custom-bootstrap-menu .navbar-nav > li.active > a.link2 {
        color: #ffffff;
        background-color: #BE4C39;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link3 {
        border-top: 3px solid #9351A6;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link3:hover,
    #custom-bootstrap-menu .navbar-nav > li > a.link3:focus {
        color: #ffffff;
        background-color: #9351A6;
    }

    #custom-bootstrap-menu .navbar-nav > li.active > a.link3 {
        color: #ffffff;
        background-color: #9351A6;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link4 {
        border-top: 3px solid #4472B9;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link4:hover,
    #custom-bootstrap-menu .navbar-nav > li > a.link4:focus {
        color: #ffffff;
        background-color: #4472B9;
    }

    #custom-bootstrap-menu .navbar-nav > li.active > a.link4 {
        color: #ffffff;
        background-color: #4472B9;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link5 {
        border-top: 3px solid #4CA454;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link5:hover,
    #custom-bootstrap-menu .navbar-nav > li > a.link5:focus {
        color: #ffffff;
        background-color: #4CA454;
    }

    #custom-bootstrap-menu .navbar-nav > li.active > a.link5 {
        color: #ffffff;
        background-color: #4CA454;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link6 {
        border-top: 3px solid #d49b00;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link6:hover,
    #custom-bootstrap-menu .navbar-nav > li > a.link6:focus {
        color: #ffffff;
        background-color: #d49b00;
    }

    #custom-bootstrap-menu .navbar-nav > li.active > a.link6 {
        color: #ffffff;
        background-color: #d49b00;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link7 {
        border-top: 3px solid #444444;
    }

    #custom-bootstrap-menu .navbar-nav > li > a.link7:hover,
    #custom-bootstrap-menu .navbar-nav > li > a.link7:focus {
        color: #ffffff;
        background-color: #444444;
    }

    #custom-bootstrap-menu .navbar-nav > li.active > a.link7 {
        color: #ffffff;
        background-color: #444444;
    }
}

#custom-bootstrap-menu .navbar-nav > li > a:hover,
#custom-bootstrap-menu .navbar-nav> li > a:focus {
    color: #5a5a5a;
    transition: color 0.25s;
}

#custom-bootstrap-menu .navbar-nav>.active > a,
#custom-bootstrap-menu .navbar-nav>.active > a:hover,
#custom-bootstrap-menu .navbar-nav>.active > a:focus {
    color: rgba(85, 85, 85, 1);
    background-color: rgba(231, 231, 231, 1);
}

#custom-bootstrap-menu .navbar-toggle {
    border-color: #ddd;
}

#custom-bootstrap-menu .navbar-toggle:hover,
#custom-bootstrap-menu .navbar-toggle:focus {
    background-color: #ddd;
}

#custom-bootstrap-menu .navbar-toggle {
    border: none;
    background-color: none;
    font-size: 2.5rem;
    cursor: pointer;
}

#custom-bootstrap-menu .navbar-toggle:hover,
#custom-bootstrap-menu .navbar-toggle:focus {
    background: none;
}

#custom-bootstrap-menu .navbar-nav > .open > a,
#custom-bootstrap-menu .navbar-nav > .open > a:hover,
#custom-bootstrap-menu .navbar-nav > .open > a:focus {
  color: #555;
  background-color: #262626;
}

@media (max-width: 767px) {
    #custom-bootstrap-menu .navbar-nav > li > a:hover,
    #custom-bootstrap-menu .navbar-nav > li > a:focus {
        background-color: #404040;
        color: #ffffff;
    }

    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > li > a {
        margin-top: 0;
        background-color: #404040;
        color: #777;
    }

    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > li > a:hover,
    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > li > a:focus {
        color: #ffffff;
        background-color: transparent;
    }

    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > .active > a,
    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > .active > a:hover,
    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > .active > a:focus {
        color: #555;
        background-color: #404040;
    }

    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > .disabled > a,
    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > .disabled > a:hover,
    #custom-bootstrap-menu .navbar-nav .open .dropdown-menu > .disabled > a:focus {
        color: #ccc;
        background-color: transparent;
    }
}

.btn {
    border: 0;
}

.btn-default {
    border-radius: 0;
    color: #ffffff;
    background-color: #333333;
}

.btn-default:hover {
    background-color: #4d4d4d;
    color: #ffffff;
}

.btn-primary {
    border-radius: 0;
    color: #ffffff;
    background-color: #1199aa;
}

.btn-primary:hover {
    background-color: #13aec1;
    color: #ffffff;
}

.btn-success {
    border-radius: 0;
    color: #ffffff;
    background-color: #77cc22;
}

.btn-success:hover {
    background-color: #84dc2c;
    color: #ffffff;
}

.btn-info {
    border-radius: 0;
    color: #ffffff;
    background-color: #8899ee;
}

.btn-info:hover {
    background-color: #9eacf1;
    color: #ffffff;
}

.btn-warning {
    border-radius: 0;
    color: #ffffff;
    background-color: #ee8822;
}

.btn-warning:hover {
    background-color: #f0953a;
    color: #ffffff;
}

.btn-danger {
    border-radius: 0;
    color: #ffffff;
    background-color: #dd5544;
}

.btn-danger:hover {
    background-color: #e1695a;
    color: #ffffff;
}

.panel {
    border: none;
    border-radius: 0;
}

.panel-body {
    box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
}

.panel-default > .panel-heading {
    border-radius: 0;
    background-color: #333;
    color: #ffffff;
}

.panel-primary > .panel-heading {
    border-radius: 0;
    background-color: #19a;
    color: #ffffff;
}

.panel-success > .panel-heading {
    border-radius: 0;
    background-color: #7c2;
    color: #ffffff;
}

.panel-info > .panel-heading {
    border-radius: 0;
    background-color: #89e;
    color: #ffffff;
}

.panel-warning > .panel-heading {
    border-radius: 0;
    background-color: #e82;
    color: #ffffff;
}

.panel-danger > .panel-heading {
    border-radius: 0;
    background-color: #d54;
    color: #ffffff;
}

.alert {
    border: 0;
}

.alert-success {
    color: #ffffff;
    background-color: #7c2;
}

.alert-info {
    color: #ffffff;
    background-color: #89e;
}

.alert-warning {
    color: #ffffff;
    background-color: #e82;
}

.alert-danger {
    color: #ffffff;
    background-color: #d54;
}

尝试添加：

@media (max-width: 767px) {
  .navbar-nav .open .dropdown-menu {
    padding-top: 0;
  }
}

你可以加padding-bottom: 0; too.