Here is an example with only CSS and Content Editable:
CSS
span
{
border: solid 1px black;
}
div
{
max-width: 200px;
}
HTML
<div>
<span contenteditable="true">sdfsd</span>
</div>
Important note regarding contenteditable
Making an HTML element contenteditable
lets users paste copied HTML elements inside of this element. This may not be ideal for your use case, so keep that in mind when choosing to use it.