<div class="red">
<label>aaa</label>
<input type="text">
</div>
.red {
border: 1px solid red;
display: flex;
flex-wrap: wrap;
margin: 0;
padding: 0;
list-style: none;
}
.inner {
display:inline-block;
border: 1px solid blue;
}
label {
box-sizing: border-box;
display:inline-block;
border: 1px solid green;
width:60%;
text-align:right;
}
input {
height:34px;
vertical-align:middle;
}