html - 如何水平和垂直居中图像

Question

我试图将此图标置于其 div 的中心，但似乎无法做到这一点。

我尝试了 top: 50% 但它不起作用。

类是ion-images，我知道我可以向它发送一个margin-top，但我想知道如何在中间正确设置它。

body {
  margin: 0;
}
.clearfix::after {
  content: "";
  display: table;
  clear: both;
}
/*-------------------HEADER*----------------*/

header {
  position: relative;
  width: 100%;
  height: 100vh;
}
.header-bg {
  position: absolute;
  width: 100%;
  height: 100%;
  background-image: url(main-bg.jpg);
  background-size: cover;
  background-position: center;
}
.header-wrapper {
  position: absolute;
  width: 100%;
  height: 100%;
  bottom: 0;
  display: flex;
  flex-flow: row wrap;
  justify-content: center;
  align-items: center;
}
.title-wrapper {
  position: relative;
  width: 320px;
  height: auto;
  margin: 0 auto;
  top: -10%;
}
.title-wrapper h1 {
  text-align: center;
  color: white;
  letter-spacing: 5.45px;
  margin-bottom: -10px;
  font-size: 62px;
  font-family: 'Raleway', sans-serif;
  border-top: 3px solid white;
  font-weight: 500;
}
.title-wrapper h3 {
  text-align: center;
  color: #35E2FF;
  letter-spacing: 3.45px;
  font-family: 'Raleway', sans-serif;
  font-size: 15px;
}
.title-wrapper h2 {
  color: white;
  font-size: 50px;
  margin-top: 80px;
  font-family: 'Raleway', sans-serif;
}
.title-wrapper h4 {
  color: white;
  font-family: 'Raleway', sans-serif;
  font-weight: 400;
  text-align: center;
  font-size: 25px;
  margin-bottom: 50px;
}
#download {
  text-align: center;
  ;
}
#demo:link {
  text-decoration: none;
  color: white;
  border: 2px solid white;
  text-align: center;
  padding: 20px 40px;
  text-transform: uppercase;
  font-size: 25px;
  font-family: 'Raleway', sans-serif;
  transition: all 200ms ease-in-out;
  -webkit-transition: all 200ms ease-in-out;
  -moz-transition: all 200ms ease-in-out;
  -o-transition: all 200ms ease-in-out;
}
#demo:hover {
  background-color: #35E2FF;
}
/*------------------------------DESCRIPTION---------------*/

#description-wrapper {
  position: relative;
  width: 100%;
  top: 0;
}
.desc-card {
  position: relative;
  width: 50%;
  height: 450px;
  margin: 0;
}
.desc-card.left {
  float: left;
  left: 0;
  background-color: #000;
}
.desc-card.right {
  float: right;
  right: 0;
  background-color: #282828;
}
#features-content {
  position: absolute;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}
#features-content h3 {
  color: white;
  font-family: 'Raleway', sans-serif;
  letter-spacing: 3.5px;
  font-weight: 500;
  font-size: 32px;
}
#features-content p {
  color: white;
  font-family: 'Raleway', sans-serif;
  font-weight: 300;
  letter-spacing: 3.5px;
}
#features-img {
  position: absolute;
  width: 100%;
  height: 100%;
  display: flex;
  flex-flow: row wrap;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}
.square {
  width: 50%;
  height: 50%;
}
.square.first {} .square.second {
  background-color: #4A4A4A;
}
.square.third {
  background-color: #4A4A4A;
}
.img-cont {
  position: relative;
  width: 100%;
  height: 100%;
}
.ion-images {
  /*THIS IS WHAT IM TRYING TO CENTER */
  color: #35E2FF;
  text-align: center;
  font-size: 115px;
}
#under-img {
  font-size: 25px;
  color: #35E2FF;
  margin-top: -10px;
  font-family: 'Raleway', sans-serif;
  font-weight: 300;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" type="text/css" href="http://code.ionicframework.com/ionicons/2.0.1/css/ionicons.min.css">
<link href="https://fonts.googleapis.com/css?family=Raleway:300,400,500" rel="stylesheet">

<!----HEADER------>
<header>
  <div class="header-bg"></div>
  <div class="header-wrapper">
    <div class="title-wrapper">

      <h1>ATLAS</h1>
      <h3>BETA</h3>
      <h4>Create Professional Digital Design in any Operating System</h4>

      <div id="download"><a href="#" id="demo">Download Now</a>
      </div>

    </div>
  </div>
</header>

<div id="description-wrapper" class="clearfix">
  <div class="desc-card left" id="features">
    <div id="features-content">
      <h3>The All In One Tool for Creative Designers In Any Operating System</h3>
      <p>ATLAS provides users the best software to do what they do best. Design</p>

    </div>
  </div>

  <div class="desc-card right" id="features-des">
    <div id="features-img">
      <div class="square first">
        <div class="img-cont">
          <div class="ion-images">
            <!--Trying to center this--->
            <p id="under-img">Photo Editing</p>
          </div>
        </div>

      </div>
      <div class="square second">

      </div>
      <div class="square third">

      </div>
      <div class="square fourth">

      </div>

    </div>
  </div>
</div>

Answer 1

尝试

.ion-images{    /*THIS IS WHAT IM TRYING TO CENTER */
        color: #35E2FF;
        text-align: center;
        font-size: 115px;
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
}

Reference