css boxes error

*{
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: Arial;
}

.container{
    max-width: 1008px;
    margin: 0 auto;
}

.header{
    display: inline-block;
    background: #02918c;
    height: 62px;
    width: 100%;
}

.url{
    display: inline-block;
    margin: 15px;
}

.main_pic{
    display: inline-block;
    max-width: 1008px;
}
.about_me{
    color: #02918c;
    font-size: 46px;
    font-weight: bold;
    text-transform: uppercase;
    text-align: center;
    margin-top: 8%;
    margin-bottom: 2%;
}

.text_under_heading{
    display: inline-block;
    color: #7e8287;
    font-size: 16px;
    text-align: center;
    line-height: 180%;
}

.boxes{
    display: inline-block;
    width: 25%;

}

.box_header{
    color: #7e8287;
    font-size: 18px;
    font-weight: bold;
    text-align: center;
}

.box_descr{
    color: #7e8287;
    font-size: 14px;
    font-weight: normal;
    line-height: 21px;
    text-align: center;
}


.footer{
    display: inline-block;
    background: #000;
    height: 79px;
    width: 100%;
    max-width: 1008px;
    bottom: 0;
}
.footer p{
    text-align: center;
    font-size: 12px normal;
    color: #7e8287;
    margin-top: 30px;
}