.btn_red,
.btn_pdf,
.btn_word,
.btn_ppt,
.btn_yellow,
.btn_green
{
margin:5px;
text-decoration: none;
display: inline-block;
padding: 1em 2em;
text-decoration: none;
color: #FFF;
border-radius: 100px;
transition: .3s;
line-height: 120%;
}

.btn_red,.btn_red:visited {background-color: #C00;}
.btn_yellow,.btn_yellow:visited {background-color: #E68C07;}
.btn_pdf,.btn_ppt:visited {background-color: #900;}
.btn_green,.btn_green:visited {background-color: #390;}
.btn_word,.btn_word:visited{background-color: #069;}
.btn_ppt,.btn_ppt:visited{background-color: #F63;}



.btn_red:hover,
.btn_pdf:hover,
.btn_word:hover,
.btn_ppt:hover,
.btn_yellow:hover,
.btn_green:hover
{
background: #f00;
color: #fff;
text-decoration: none;
}