.button_mainform {
    display: inline-block;
    background: #838383;
    color: #fff;
    border: 0;
    outline: 0;
    font-family: 'Roboto', sans-serif;
    font-size: 17px;
    font-weight: 300;
    text-decoration: none;
    text-transform: uppercase;
    padding: 17px 21px;
    cursor: pointer;
    -webkit-transition: background 0.4s;
    -o-transition: background 0.4s;
    transition: background 0.4s;
    margin-top: 10px;
	float: right
}

.button_mainform:after {
    content: '';
    display: inline-block;
    width: 10px;
    height: 11px;
    background: url(https://asm-tula.ru/img/arrow45-icon.png);
}

.button_mainform:hover {background: #424242;}