Responsive Width Calculation

Question

How to calculate for different responsive box? if width container was 100%, the box in it should be how much %?

Answer 1

https://code.sololearn.com/Wi0l1NKqOxlf as you and I can see it's okay)
In case you want to use borders you should use box-sizing css rule (or reduce width).
Alternative variant (no floats, display: table) https://code.sololearn.com/WxRE9Wktwuow
Alternative variant (no floats, not tables, flexbox (for more modern browsers)) https://code.sololearn.com/WPRtlH2y0y0b

Answer 2

Thank you, that's really help me.

Answer 3

Well, as for me, I can't understand what do you want

Answer 4

I mean like this.
.container{width: 100%;}
.main-item{width: 75%, float: left;}
.sidebar{width: 25%, float: right;}
in HTML I put
<div class="container">
<div class="main-item"></div>
<div class="sidebar"></div>
</div>
Is it ok for width?

Answer 5

You should replace commas (",") with semicolons (";") in your css.

Answer 6

ya ya ya I know it is my fault, but how about the width? is it ok?