body, html {
    margin: 0;
    padding: 0;
    font-family: 'Roboto', sans-serif;
}

.header {
    text-align: center;
    width: 100%;
    height: 500px;
    background-image: url("louka2.jpg");
    background-repeat: no-repeat;
    background-size: cover;
}


.header-text {
    margin-top: -80px;
    padding: 10px;
    background-color: rgba(0, 0, 0, 0.5);
    font-size: 50px;
    text-align: center;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
}

.obsah {
    width: 80%;
    text-align: center;
    border: 1px solid darkgray;
    margin: 0 auto;
    display: block;
    margin-top: 10px;
    padding: 10px;
}

#nav ul {
    text-align: center;
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
    display: block;
}
  
#nav li {
    float: left;
}
  
#nav li a {
    display: inline-block;
    color: white;
    text-align: center;
    padding: 14px 50px;
    text-decoration: none;
}
#nav {
    position: sticky;
    position: -webkit-sticky;
}
#nav li a:hover {
    background-color: gray;
}

.img {
    height: 120px;
    display: inline-block;
    margin: 3px;
    transition: transform .2s; 
    -webkit-box-shadow: 3px 3px 3px 0px rgba(0,0,0,0.75);
    -moz-box-shadow: 3px 3px 3px 0px rgba(0,0,0,0.75);
    box-shadow: 3px 3px 3px 0px rgba(0,0,0,0.75);
}
.img:hover {
    transform: scale(1.5);
}
#rozklad-tbl {
    border: 1px solid black !important;
    margin: 0 auto;
    text-align: center;
    border-collapse: collapse;
}
#rozklad-tbl tr, td, th {
    border: 1px solid gray;
    padding: 5px;
}

footer {
    text-align: center;
    padding: 20px;
}