Ho I make column bigger and smaller in Bootsrap?

I have this code on my webpage and I made with Bootstrap

<div class="row">
<div class="col-md-11">
    Here I have contant
</div>
<div class="col-md-1">
    Here I have contant
</div>

and I need for this column, that first column to be smaller, 10.5 size and second column to be bigger, 1.5 size. Can I do with width in CSS? Can you help me with this?

Thanks