style and js into first line in functions

What is this? It’s show all in file ??

insert-html-snippet\admin\admin-notices.php

<style>
#TB_window { width:50% !important;  height: 100px !important;
margin-left: 25% !important; 
left: 0% !important; 
}
</style>
<?php add_thickbox();?>
<script type="text/javascript">
function share_html_code_snippet(){
tb_show("Share on","#TB_inline?width=500&height=75&inlineId=show_share_icons_ihs&class=thickbox");
}
</script>