SOURCE

<div class="search-bar">
  <div class="search-bar-left">
    <div class="search-bar-back">
      <i class="back-icon"><</i> 返回
    </div>
  </div>
  <div class="search-bar-main">
    <div class="search-bar-form">
      <i class="search-icon">O</i>
      <input class="search-bar-input" type="text" placeholder="请输入搜索内容" />
      <i class="clear-icon">X</i>
    </div>
  </div>
  <div class="search-bar-right">
    <div class="search-bar-cancel">
      取消
      <i>X</i>
    </div> 
  </div>
</div>

.search-bar {
  height: 46px;
  display: flex;
  padding: 0 16px;
  background: #fff;
}

.search-bar-left {
  display: flex;
  align-items: center;
}
.search-bar-main {
  flex: 1;
  height: 100%;
  padding: 8px 10px;
  box-sizing: border-box;
}
.search-bar-form {
  position: relative;
  border-radius: 100px;
  padding: 0 35px;
  border: 1px solid #999;
  background: #eee;
  height: 100%;
}
.search-icon {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
}
.clear-icon {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
}

.search-bar-input {
  width: 100%;
  display: inline-block;
  height: 100%;
  border: 0;
  font-size: 16px;
  outline: none;
  background: transparent;
}

.search-bar-right {
  display: flex;
  align-items: center;
}