body {
    background-image: url("../img/background.jpg");
}

a {
    text-decoration: none;
    font-size: 25px;
    font-family: 'oswald', sans-serif;
    color: #c0c0c0;
}

.kwadrat {
    display: inline-block;
    width: 400px;
    height: 400px;
    line-height: 125px;
    margin-left: 40px;
    margin-top: 270px;
    display: inline-block;
    text-align: center;
}

.kolo_1, .kolo_2, .kolo_3, .kolo_4 {
    border-radius: 50%;
    background-color: rgba(0,0,0,0.7);
    width: 130px;
    height: 130px;
    margin: 140px 0 0 130px;
    cursor: pointer;
}

.kolo1_1, .kolo1_2, .kolo1_3, .kolo1_4, .kolo1_5, .kolo1_6, .kolo2_1, .kolo2_2, .kolo2_3, .kolo2_4, .kolo2_5, .kolo2_6, .kolo3_1, .kolo3_2, .kolo3_3, .kolo3_4, .kolo3_5, .kolo3_6, .kolo4_1, .kolo4_2, .kolo4_3, .kolo4_4, .kolo4_5, .kolo4_6 {
    border-radius: 50%;
    background-color: rgba(0,0,0,0.7);
    width: 130px;
    height: 130px;
    position: absolute;
    margin-top: -130px;
    margin-left: 130px;
    display: none;
}