The release of Wordpress 3.8 gave us a bright shiny new admin which included the updated log-in screen shown here. The problem is, if you're like us, you like to customize the log-in screen for your clients with their logo. Once you upgrade to 3.8, that nice logo will be be squeezed down to 80px by 80px because of changes to wp-admin.css.
There is some good information for overriding wp-admin.css in your theme stylesheet on the Wordpress website (http://codex.wordpress.org/Customizing_the_Login_Form#Styling_Your_Login) but if you used functions.php to insert your custom logo, there's an easier way.
// Replaces the login header logo
function namespace_login_style() {
echo '
<style>
.login h1 a {
background-image: url(' . get_template_directory_uri() . '/library/images/login_logo.png ) !important;
background-size: 302px 72px !important;
width: 302px !important;
}
</style>
';
}
We have added two new classes in addition to the standard background image style to override the 80px by 80px specs added by 3.8s new wp-admin.css
Hope this works for you too. Let us know!