Custom header widget size problem…

Hi.
I added a widget for my header. But it stretches all the way across the top, so does not react to it’s size dimensions or a z-index position… Have no idea what I did wrong.

Here is the functions.php file code:

register_sidebar( array(
    'name' => __( 'Header Widget Area Left', 'My-Theme-Name' ),
    'id' => 'header-widget-area-left',
    'description' => __( 'The header left widget area', 'my-theme-name' ),
    'before_widget' => '<li id="%1$s" class="widget-container %2$s">',
    'after_widget' => '</li>',
    'before_title' => '<h3 class="widget-title">',
    'after_title' => '</h3>',
) );

Here is what I put in the header:

<?php

if ( is_active_sidebar( 'header-widget-area-left' )) {

dynamic_sidebar( 'header-widget-area-left' );
}
?>

And here is CSS:

#header-widget-area-left {
    float: left;
    position: absolute;
    width: 150px;
    height: 233px;
    z-index: 50;
}

Any ideas?

Thanks.