body {
    margin: 0;
    padding: 20px;
    background-color: #f0f0f0;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
}

.grid-container {
    display:grid;
    /* vytvoříme 3 sloupce se stejnou říkou -> 1fr - 1fraction(část) */
    grid-template-columns: 1fr 1fr 1fr;
    gap: 20px;

    max-width: 1200px;
    margin: 0 auto;
}

.grid-item{
    background-color: bisque;
    padding: 20px;
    border-radius: 15px;
    text-align: center;

    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: traform 0.3s ease, box-shadow 0.3s ease;
}

.grid-item h3{
    margin-top: 0;
    color: #444;
}

.grid-item p {
    color: #777;
    margin-bottom: 0;
}

.grid-item:hover{
    transform: scale(1.05);
    box-shadow: 0 8px 16px rgba(0,0,0,0.2);
    cursor: pointer;
}

/* odd - liché položky */
.grid-item:nth-child(odd){
    background-color: aqua;
}
/* even - sudé položky */
.grid-item:nth-child(even){
    background-color: aquamarine;
}
.grid-item:first-child {
    background-color: indianred;
    grid-column: span 2;
}
.grid-item:last-child {
    background-color: rosybrown;
}
/* 768px max šířka pro tablety */
@media only screen and (max-width: 768px) {
    .grid-container {
        grid-template-columns: 1fr 1fr;
    }
    .grid-item:first-child {
        grid-column: span 1;
    }
}

/* 480px max šířka pro telefony */
@media only screen and (max-width: 480px) {
    body {
        padding: 10px;
    }
    .grid-container {
        grid-template-columns: 1fr;
        gap: 10px;
    }
    .grid-item {
        padding: 20px;
    }
    h1 {
        font-size: 24px;
    }
}
/* pro každý 3. potomek (3,6,9,12...*/
.grid-item:nth-child(3n) {
    border: 3px solid #ff6b6b;
}

/* pro všechny kromě(not) první */
.grid-item:not(:first-child){
    opacity: 0.5;
}

/*první 3 položky*/
.grid-item:nth-child(-n+3) {
    font-weight: bold;
}