WordPress Twenty Ten Theme with hoizontal menu css

style.css

/*
Theme Name: Twenty Ten Horizontal Subnav
Theme URI: http://blog.mzx.mobi/adding-horizontal-subnav-to-the-twenty-ten-theme.html
Description: The 2010 theme for WordPress is stylish, customizable, simple, and readable -- make it yours with a custom menu, header image, and background. Twenty Ten supports six widgetized areas (two in the sidebar, four in the footer) and featured images (thumbnails for gallery posts and custom header images for posts and pages). It includes stylesheets for print and the admin Visual Editor, special styles for posts in the "Asides" and "Gallery" categories, and has an optional one-column page template that removes the sidebar.
Author: the WordPress team, modified by bmcculley
Author URI: http://mzx.mobi
Version: 0.1
Tags: black, blue, white, two-columns, fixed-layout, custom-header, custom-background, threaded-comments, sticky-post, translation-ready, microformats, rtl-language-support, editor-style
Template: twentyten
*/

@import url("../twentyten/style.css");

/* =Header
-------------------------------------------------------------- */

#site-description {
font-size: 12px;
}

/* =Menu
-------------------------------------------------------------- */

#mm {
background: #000;
display: block;
float: left;
font-family: "Helvetica Neue", Arial, Helvetica, "Nimbus Sans L", sans-serif;
margin: 0 auto;
width: 940px;
position: relative;
}
#mm .m-header,
div.menu {
font-size: 13px;
margin-left: 12px;
width: 928px;
}
#mm .m-header ul,
div.menu ul {
list-style: none;
margin: 0;
}
#mm .m-header li,
div.menu li {
float: left;
position: static;
}
#mm a {
color: #aaa;
display: block;
line-height: 38px;
padding: 0 10px;
text-decoration: none;
}
#mm ul ul {
background: #1376c9;
border-top:1px solid #fff;
display: none;
height: 38px;
list-style-type: none;
left: 0;
top: 38px;
padding-left: 12px;
width: 928px;
z-index: 99999;
-webkit-border-radius: 0 0 5px 5px;
-moz-border-radius: 0 0 5px 5px;
border-radius: 0 0 5px 5px;
}
#mm ul ul li {
display: inline;
float: left;
list-style: none;
padding: 0;
}
#mm ul ul ul {

}
#mm ul ul a {
height: auto;
color:#fff;
}
#mm li:hover > a {
background: #1376c9;
color:#fff;
}
#mm ul ul :hover > a {
background: #333;
color:#fff;
}
#mm ul li:hover > ul {
display: inline;
left: 0px;
position: absolute;
top: 35px;
}
#mm ul li.current_page_item > a,
#mm ul li.current-menu-ancestor > a,
#mm ul li.current-menu-item > a,
#mm ul li.current-menu-parent > a {
color: #fff;
}
* html #mm ul li.current_page_item a,
* html #mm ul li.current-menu-ancestor a,
* html #mm ul li.current-menu-item a,
* html #mm ul li.current-menu-parent a,
* html #mm ul li a:hover {
color: #fff;
}

/* =Images
-------------------------------------------------------------- */
#main img,
.wp-caption img {
height: auto;
max-width: 622px;
}

/* =Footer
-------------------------------------------------------------- */

#site-generator {
font-style: italic;
position: relative;
}
#site-generator a {
background: none;
color: #666;
display: inline-block;
line-height: 16px;
padding-left: 0px;
text-decoration: none;
}
#site-generator a:hover {
text-decoration: underline;
}

Get the full child theme from the repository.