_sass/minimal-mistakes/_masthead.scss

/* ==========================================================================
   MASTHEAD
   ========================================================================== */

.masthead {
  background-color: $masthead-background-color;
  position: absolute;
  top: 0;
  width: 100%;
  -webkit-animation: intro 0.3s both;
          animation: intro 0.3s both;
  -webkit-animation-delay: 0.15s;
          animation-delay: 0.15s;
  z-index: 20;

  &__inner-wrap {
    @include container;
    @include clearfix;
    display: -webkit-box;
    display: flex;
    -webkit-box-pack: justify;
     justify-content: space-between;
    font-family: $sans-serif-narrow;
    margin-left: 10%;
    margin-right: 10%;

    @include breakpoint($x-large) {
      max-width: $x-large;
    }

    nav {
      z-index: 10;
    }

    a {
      text-decoration: none;
    }
  }
}

.site-title {
  display: -webkit-box;
  display: flex;
  align-self: stretch;
  -webkit-box-align: center;
        align-items: center;
  z-index: 20;

  img {
      width: 300px;
      height: 50px;
  }
}

.greedy-nav {
    a.site-title {
        margin-right: 0;
        padding: 0 0;
    }
}

.masthead__menu {
  width: 100%;

  .site-nav {
    margin-left: 0;

    @include breakpoint($small) {
      float: right;
    }
  }

  ul {
    margin: 0;
    padding: 0;
    clear: both;
    list-style-type: none;
  }
}

.masthead__menu-item {
  display: block;
  list-style-type: none;
  white-space: nowrap;

  &--lg {
    padding-right: 2em;
    font-weight: 700;
  }
}

.def-nav-li {
  display: block;
  list-style-type: none;
  white-space: nowrap;

  .def-children-show-en {
    display: none;
    position: absolute;
    top: 55px;
    width: 140px;

    li {
      background: #000;
      opacity: 0.8;
      padding: 10px 20px;
      margin-bottom: 1px;

      a {
        width: 100%;
      }
    }
  }

  .def-children-show-cn {
    display: none;
    position: absolute;
    top: 55px;
    width: 108px;

    li {
      background: #000;
      opacity: 0.8;
      padding: 10px 20px;
      margin-bottom: 1px;

      a {
        width: 100%;
      }
    }
  }
}