<!DOCTYPE html>
<!--
 | Sibling inline boxes of ancestor inline boxes that end up on the same line
 | as a box can affect the line height. When combined with vertical-align:top
 | or vertical-align:bottom, that affects vertical positioning of a box.
 |   https://www.w3.org/TR/CSS21/visudet.html#line-height
 -->
<html>
<head>
 <style>
    body {
      margin: 0px;
      font-family: Roboto;
      font-size: 16px;
    }
    .small-box {
      display: inline;
      font-size: 20px;
      background-color: #2962FF;
    }
    .medium-box {
      display: inline;
      font-size: 30px;
      background-color: #2979FF;
    }
    .large-box {
      display: inline;
      font-size: 60px;
      background-color: #82B1FF;
    }
 </style>
</head>
<body>

<span class="medium-box">
 text
 <span style="vertical-align:top" class="small-box">
   top
 </span>
</span>
<span class="large-box">
big
</span>

</body>
</html>