How to stop CSS blog date from streching Twentyten

Hi I’ve used some CSS to style the date next to each blog entry as in Twentyten theme it is just plain text. However whatever I seem to do it stretches it wider than specified in code.

Please click here to see image to understand what I mean

The CSS I am using is as follows:

.calendar {
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    border-radius: 5px;
    box-shadow: 0 0 1px 1px rgba(0, 0, 0, 0.4);
    -webkit-box-shadow: 0 0 1px 1px rgba(0, 0, 0, 0.4);
    -moz-box-shadow: 0 1px 1px rgba(0, 0, 0, 0.4);
    background: #ebebeb;
    border: 1px solid #555555;
    font-family: "Helvetica Neue", Arial, Helvetica, "Nimbus Sans L", sans-serif;
    float: left;
    margin-right: 20px;
    width: 41px;
    height: 47px;
    font-size: 12px;
}
.calendar > span {
    display: block;
}
.calendar > .month {
    -moz-border-top-left-radius: 3px;
    -moz-border-top-right-radius: 3px;
    -webkit-border-top-left-radius: 3px;
    -webkit-border-top-right-radius: 3px;
    border-top-left-radius: 3px;
    border-top-right-radius: 3px;
    background: #53A4E6;
    border-bottom: 1px solid #555555;
    font-weight: bold;
    padding: 0 2px 0 2px;
    text-align: center;
    color: #ffffff;
    line-height: 1.5;
}
.calendar > .day {
    -moz-border-bottom-left-radius: 3px;
    -moz-border-botton-right-radius: 3px;
    -webkit-border-bottom-left-radius: 3px;
    -webkit-border-bottom-right-radius: 3px;
    border-bottom-left-radius: 3px;
    border-bottom-right-radius: 3px;
    background: #f6f6f6;
    padding: 2px 0 2px 0;
    text-align: center;
    font-weight: bold;
    font-size: 18px;
    color: #000000;
    line-height: 1.3;
}
.entry-title {
       clear: right;
}

I have placed the code in the loop.php file in the location:

<div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
<div class="calendar">
    <span class="month"><?php the_time("M", get_option('date_format')); ?></span>
    <span class="day"><?php the_time("d", get_option('date_format')); ?></span>
</div><!-- calendar -->
			<h2 class="entry-title"><a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( sprintf( __( 'Permalink to %s', 'twentyten' ), the_title_attribute( 'echo=0' ) ) ); ?>" rel="bookmark"><?php the_title(); ?></a></h2>