.heading {
    text-align: center;
    margin: 20px 0;
}

.gallery {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    /* space between items */
    padding: 10px;
    justify-content: center;
    /* center the items */
}

.gallery-item {
    flex: 1 1 calc(25% - 20px);
    /* responsive item size */
    box-sizing: border-box;
    overflow: hidden;
    /*border: 1px solid #ddd;*/
    text-align: center;
}

    .gallery-item img {
        width: 100%;
        height: auto;
        display: block;
        object-fit: cover;
        cursor: pointer;
    }

@media (max-width: 1200px) {
    .gallery-item {
        flex: 1 1 calc(33.33% - 20px);
        /* 3 columns */
    }
}

@media (max-width: 900px) {
    .gallery-item {
        flex: 1 1 calc(50% - 20px);
        /* 2 columns */
    }
}

@media (max-width: 600px) {
    .gallery-item {
        flex: 1 1 calc(100% - 20px);
        /* 1 column */
    }
}

/* Modal Styles */
.modal {
    display: none;
    /* Hidden by default */
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.9);
    /* Black background with opacity */
}

.modal-content {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
}

.close {
    position: absolute;
    top: 20px;
    right: 35px;
    color: #fff;
    font-size: 40px;
    font-weight: bold;
    transition: 0.3s;
    cursor: pointer;
}

    .close:hover,
    .close:focus {
        color: #bbb;
        text-decoration: none;
        cursor: pointer;
    }