垂直对齐中间，用于不固定高度的响应式顶部导航

Question

我想在顶部导航栏的垂直下方将文本居中。我试图给。header一个height：3em;并使用vertical-align：middle;，但是我的响应式折叠菜单无法处理固定高度。该菜单不再显示，因为现在高度已固定。我也尝试使用.parent padding：50％0;和.child margin：0 auto;，但是我不明白这一点。我也尝试使用line-height：40px，它看起来还可以-但我的burger-menu-icon不会以这种方式居中。我的burger-menu-icon图标在使用％和翻译时也有问题，我可以通过这种方式居中-但是通过折叠菜单，它也可以移至50％，这是不需要的。更改为固定/绝对将使％崩溃并转换...

html {
  font-size: calc(1.3em + 1vw)
}

body {
  margin: 0;
  font-family: Helvetica, sans-serif;
  background-color: #fafafa;
}

/* header */

.header {
  position: fixed;
  overflow: auto;
  width: 100%;
  max-width: 30em;
	margin-left: auto;
	margin-right: auto;
  box-shadow: 0 1px 3px rgba(0, 0, 0, .12), 0 1px 2px rgba(0, 0, 0, .24);
  background: #ffb347;  /* fallback for old browsers */
  background: -webkit-linear-gradient(to right, #ffb347, #ffcc33);  /* Chrome 10-25, Safari 5.1-6 */
  background: linear-gradient(to right, #ffb347, #ffcc33); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */ 
}

.header ul {
  margin: 0;
  padding: 0;
  list-style: none;
  overflow: hidden;
}

.header li a {
  display: block;
  padding: 15px 20px;
  text-decoration: none;
  font-size: 0.7em;
  color: #000;
  background-color: blue;
}

.header li a:hover,
.header .menu-btn:hover {
  background-color: blue;
}

.header .logo {
  display: block;
  float: left;
  font-size: 1.3em;
  padding: 15px 20px;
  text-decoration: none;
  color: #000;
  background-color: blue;
}

.header .logo:hover {
}

/* menu */

.header .menu {
  clear: both;
  max-height: 0;
  transition: max-height .2s ease-out;
}

/* menu icon */

.header .menu-icon {
  cursor: pointer;
  display: inline-block;
  float: right;
  display:table-cell;
  vertical-align:middle;
  text-align:center;
  padding: 0.9em 0.4em;
  user-select: none;
  background: blue; 
}

.header .menu-icon .navicon {
  background: #333;
  display: block;
  height: 7px;
  position: relative;
  transition: background .2s ease-out;
  width: 40px;
}

.header .menu-icon .navicon:before,
.header .menu-icon .navicon:after {
  background: #333;
  content: '';
  display: block;
  height: 100%;
  position: absolute;
  transition: all .2s ease-out;
  width: 100%;
}

.header .menu-icon .navicon:before {
  top: 15px;
}

.header .menu-icon .navicon:after {
  top: -15px;
}

/* menu btn */

.header .menu-btn {
  display: none;
}

.header .menu-btn:checked ~ .menu {
  max-height: 100%;

}

.header .menu-btn:checked ~ .menu-icon .navicon {
  background: transparent;
}

.header .menu-btn:checked ~ .menu-icon .navicon:before {
  transform: rotate(-45deg);
}

.header .menu-btn:checked ~ .menu-icon .navicon:after {
  transform: rotate(45deg);
}

.header .menu-btn:checked ~ .menu-icon:not(.steps) .navicon:before,
.header .menu-btn:checked ~ .menu-icon:not(.steps) .navicon:after {
  top: 0;
}

@media (min-width: 920px) {
  .header {
    position: relative;
  }
  .header li {
    float: left;   
  }
  .header li a {
  }
  .header .menu {
    clear: none;
    float: right;
    max-height: none;
  }
  .header .menu-icon {
    display: none;
  }
}

<div class="header">
    <a href="" class="logo">LOREM <b>IPSUM</b></a>
    <input class="menu-btn" type="checkbox" id="menu-btn" />
    <label class="menu-icon" for="menu-btn"><span class="navicon"></span></label>
    <ul class="menu">
      <li><a href="#work"> <b>Lorem</b></a></li>
      <li><a href="#about"><b>Ipsum</b></a></li>
      <li><a href="#careers"><b>Dolor</b></a></li>
      <li><a href="#contact"><b>Sit</b></a></li>
    </ul>
  </div>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>

以整页开始！

Answer 1

您可以使用csstransformtransform: translateY(10%);检查代码段。

html {
  font-size: calc(1.3em + 1vw)
}

body {
  margin: 0;
  font-family: Helvetica, sans-serif;
  background-color: #fafafa;
}


/* header */

.header {
  position: fixed;
  overflow: auto;
  width: 100%;
  max-width: 30em;
  margin-left: auto;
  margin-right: auto;
  box-shadow: 0 1px 3px rgba(0, 0, 0, .12), 0 1px 2px rgba(0, 0, 0, .24);
  background: #ffb347;
  /* fallback for old browsers */
  background: -webkit-linear-gradient(to right, #ffb347, #ffcc33);
  /* Chrome 10-25, Safari 5.1-6 */
  background: linear-gradient(to right, #ffb347, #ffcc33);
  /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */
}

.header ul {
  margin: 0;
  padding: 0;
  list-style: none;
  overflow: hidden;
}

.header li a {
  display: block;
  padding: 15px 20px;
  text-decoration: none;
  font-size: 0.7em;
  color: #000;
  background-color: blue;
}

.header li a:hover,
.header .menu-btn:hover {
  background-color: blue;
}

.header .logo {
  display: block;
  float: left;
  font-size: 1.3em;
  padding: 15px 20px;
  text-decoration: none;
  color: #000;
  background-color: blue;
}

.header .logo:hover {}


/* menu */

.header .menu {
  clear: both;
  max-height: 0;
  transition: max-height .2s ease-out;
}


/* menu icon */

.header .menu-icon {
  cursor: pointer;
  display: inline-block;
  float: right;
  display: table-cell;
  vertical-align: middle;
  text-align: center;
  padding: 0.9em 0.4em;
  user-select: none;
  background: blue;
  transform: translateY(10%);
}

.header .menu-icon .navicon {
  background: #333;
  display: block;
  height: 7px;
  position: relative;
  transition: background .2s ease-out;
  width: 40px;
}

.header .menu-icon .navicon:before,
.header .menu-icon .navicon:after {
  background: #333;
  content: '';
  display: block;
  height: 100%;
  position: absolute;
  transition: all .2s ease-out;
  width: 100%;
}

.header .menu-icon .navicon:before {
  top: 15px;
}

.header .menu-icon .navicon:after {
  top: -15px;
}


/* menu btn */

.header .menu-btn {
  display: none;
}

.header .menu-btn:checked~.menu {
  max-height: 100%;
}

.header .menu-btn:checked~.menu-icon .navicon {
  background: transparent;
}

.header .menu-btn:checked~.menu-icon .navicon:before {
  transform: rotate(-45deg);
}

.header .menu-btn:checked~.menu-icon .navicon:after {
  transform: rotate(45deg);
}

.header .menu-btn:checked~.menu-icon:not(.steps) .navicon:before,
.header .menu-btn:checked~.menu-icon:not(.steps) .navicon:after {
  top: 0;
}

@media (min-width: 920px) {
  .header {
    position: relative;
  }
  .header li {
    float: left;
  }
  .header li a {}
  .header .menu {
    clear: none;
    float: right;
    max-height: none;
  }
  .header .menu-icon {
    display: none;
  }
}

<div class="header">
  <a href="" class="logo">LOREM <b>IPSUM</b></a>
  <input class="menu-btn" type="checkbox" id="menu-btn" />
  <label class="menu-icon" for="menu-btn"><span class="navicon"></span></label>
  <ul class="menu">
    <li>
      <a href="#work"> <b>Lorem</b></a>
    </li>
    <li><a href="#about"><b>Ipsum</b></a></li>
    <li><a href="#careers"><b>Dolor</b></a></li>
    <li><a href="#contact"><b>Sit</b></a></li>
  </ul>
</div>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>
<br><br><br>

Answer 2

尝试此CSS

.header {
    position: relative;
    display: flex;
    align-items: center;
    width: 100%;
    justify-content: space-between;
}