html - CSS3 - Div width=100% pushes content to new line instead of using remaining space -

i have looked around solution problem, haven't found works. bit noobish apologize bit rusty in css.

all have 2 div elements aligned side side horizontally take 100% of window's height , width. div on left have fixed width value , div on right take remaining space.

the solution simple , sure missing basic concept css causing issue if me out , maybe point me literature me understand doing wrong appreciate it.

fiddle link code

the html code:

<div id="leftsidebar">left sidebar</div> <div id="content">content</div> 

the css:

html, body{     height: 100%;     width: 100%; } #leftsidebar{     width:175px;     height:100%;     background-color:#567880; } #content{     width:100%;     height:100%;     background-color:#00a0a0; } 

you can floats instead:

#leftsidebar{     width:175px;     height:100%;     float: left;     background-color:#567880; } #content{     height:100%;     background-color:#00a0a0; }