body {
    font-family: "Arial", "Arial Black", serif;
    text-align: center;

    background-color: lightsteelblue;
}

section p {
    font-weight: bold;
}
a {
    color: cornflowerblue;
}
#plan {
    width: 50%;
    text-align: left;
    float: left;
    clear: left;
}
#plan table {
    text-align: center;
    border-spacing: 20px 10px;
    padding: 10px;
}
table tr>td {
    background-color: lightgray;
    border: 3px solid gray;
    border-radius: 10px;
    padding: 3px;

    font-weight: bold;

}
#zdroje {
    width: 50%;
    text-align: left;
    float: right;
    clear: right;
}
#zdroje table {
    text-align: center;
    border-spacing: 20px 10px;
    padding: 10px;
}
#prezentacia {
    width: 50%;
    text-align: left;
    float: right;
    clear: right;
}
#prezentacia table {
    text-align: center;
    border-spacing: 20px 10px;
    padding: 10px;
    width: available;
    margin: auto;
}
#dennik {
    width: 50%;
    text-align: left;
    float: left;
    clear: left;
}
#dennik table {
    text-align: center;
    border-spacing: 20px 10px;
    padding: 10px;
}