body{
    background: black url(https://img1.akspic.ru/originals/0/3/7/6/5/156730-uprazhnenie-fitness_centr-fizicheskaya_podgotovka-silovye_trenirovki-sustav-3840x2160.jpg);
    color: white;
    background-repeat: no-repeat;
}
.btn{
    color: white;
}
.btn:hover{
    color: rgb(201, 200, 200);
}
.cont1, .cont2, .cont3, .cont4, .cont5{
    border: 1px solid white;
}