/*
======== table of content. ===============

summary:concept要素

==========================================
*/

#sec_main .txt_intro span { margin-left:1em; }
#sec_main section:last-child {}
#sec_main section:last-child p { float:left; width:50%; margin-top:0; }
#sec_main section:last-child div { float:right; width:46%; }

@media screen and (max-width: 800px) {
#sec_main section:last-child p { float:none; width:100%; }
#sec_main section:last-child div { float:none; margin-top:30px; width:100%; text-align:center; }
}

@media screen and (max-width: 580px) {
#sec_main .txt_intro span { margin-left:0; }
}