Search box

<div class="container">
<!-- Text input -->
<input type="text" class="container__input" />
<!-- Search icon sticks to the left or right -->
...
</div>
.container {
display: flex;
/* If you want to place the icon before the text input */
flex-direction: row-reverse;
/* Border */
border: 1px solid rgba(0, 0, 0, 0.3);
}
.container__input {
border-color: transparent;
/* Take available width */
flex: 1;
}