html, body {
    padding: 0;
    margin: 0;
    background-color: #84cc16;
    height: 100vh;
}
.kolayplan {
    height: 100%;
    width: 100%;
    background: url(https://kolayplan.net/static/media/logo-transparan.76c953e7294c4265d145.png) no-repeat center;
}