* {
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    font-size: medium;
    margin: 0;
    padding: 0;
    background-color: #e0f7fa;
    color: #333;
}

header {
    background-color: #0056d7;
    color: white;
    padding: 20px;
    text-align: center;
    position: relative;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

nav ul li {
    display: inline;
    margin: 0 15px;
    position: relative;
}

nav ul li a {
    color: white;
    text-decoration: none;
    transition: color 0.3s;
}

nav ul li a::after {
    content: '';
    display: block;
    width: 100%;
    height: 2px;
    background: white;
    position: absolute;
    left: 0;
    bottom: -5px;
    transform: scaleX(0);
    transition: transform 1s ease;
}

nav ul li a:hover::after {
    transform: scaleX(1);
}

.active::after {
    transform: scaleX(1);
}

.closed {
    cursor: not-allowed;
}

.closed::after {
    display: none;
}

.closed:hover {
    color: white;
}

main {
    padding: 20px;
    position: relative;
    z-index: 2;
}

.section {
    max-width: 800px;
    margin: 40px auto;
    padding: 20px;
    background-color: white;
    border: 1px solid #ddd;
    border-radius: 5px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.3);
}

h2 {
    border-bottom: 3px solid #0056d7;
    padding-bottom: 10px;
    margin-bottom: 20px;
    text-align: center;
}

#razredi h3 {
    text-transform: uppercase;
}

article {
    background-color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    border: 1px solid #ddd;
    border-radius: 5px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

article:hover {
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.3);
}

article h3 {
    margin-bottom: 0px;
}

article p {
    margin-bottom: 25px;
}

.btn {
    background-color: #0056d7;
    color: white;
    text-decoration: none;
    border-radius: 7.5px;
    padding: 10px 20px;
    cursor: pointer;
    transition: background-color 0.3s;
    width: 100%;
    text-align: center;
}

.btn:hover {
    background-color: #1472ff;
}

.closed2 {
    cursor: not-allowed;
    border: 0px;
    font-family: 'Arial', sans-serif;
    font-size: medium;
}

.closed2:hover {
    color: white;
}

footer {
    background-color: #0056d7;
    color: white;
    text-align: center;
    padding: 10px;
    position: relative;
    bottom: 0;
    width: 100%;
    z-index: 2;
}

@media (max-width: 600px) {
    nav ul li {
        display: block;
        margin: 10px 0;
    }

    .section {
        max-width: 90%;
    }
}


/*************************
    POPIS ZADATAKA
*************************/
.popis {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: space-around;
}

.zadatak {
    background-color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 45%;
    border: 1px solid #ddd;
    border-radius: 5px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.zadatak:hover {
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.3);
}

.zadatak h3 {
    margin-bottom: 0px;
}

.zadatak p {
    margin-bottom: 25px;
}