.hidden   {display: none;}
.centered {text-align: center;}

.help_title {font-weight: bold;}

.help_ver, .span_ver,
.span_ver_date {font-style: italic;}

.span_author,
.span_author_ru {}

html,
body {
    height: 100%;
    margin: 0;
}

hr {
    margin:  5px 0;
    padding: 0;
    border:  0;
    height:  1px;
    background-image: -webkit-linear-gradient(left,rgba(0,0,0,0),rgba(0,0,0,0.25),rgba(0,0,0,0));
    background-image: -moz-linear-gradient(left,rgba(0,0,0,0),rgba(0,0,0,0.25),rgba(0,0,0,0));
    background-image: -ms-linear-gradient(left,rgba(0,0,0,0),rgba(0,0,0,0.25),rgba(0,0,0,0));
    background-image: -o-linear-gradient(left,rgba(0,0,0,0),rgba(0,0,0,0.25),rgba(0,0,0,0));
    background:       linear-gradient(left,rgba(0,0,0,0),rgba(0,0,0,0.25),rgba(0,0,0, 0));
}

article {
    margin: 10px; 
}