html

<div class="flex">
      <div class="l_flex">
        <div class="item"></div>
      </div>
      <div class="r_flex">
        <div class="item"></div>
      </div>
    </div>

css

      .flex {
        background-color: rgb(224, 224, 224);
        display: flex;
        flex-wrap: wrap;
        justify-content: space-between;
        padding: 12px 12px 0;
      }
      .flex .l_flex {
        display: flex;
        flex-direction: column;
        width: 48%;
      }
      .flex .r_flex {
        display: flex;
        flex-direction: column;
        width: 48%;
      }
      .flex .item {
        width: 100%;
        height: auto;
        border-radius: 10px;
        overflow: hidden;
        background-color: white;
        margin-bottom: 10px;
      }