.portfolio-container { /* Renamed */
    padding: 50px 0;
}

/* --- Filter Navigation Styling (No change needed here) --- */

.filter-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0;
    margin-bottom: 10px;
    padding: 0 5%;
}

.filter-btn {
    background-color: var(--secondary-color);
    color: var(--primary-color);
    border: 1px solid #ddd;
    padding: 8px 15px;
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: background-color 0.3s, color 0.3s;
    font-size: 14px;
    white-space: nowrap;
    margin: 0 10px 10px 0;
}

.filter-btn:hover {
    background-color: #e0e0e0;
}

.filter-btn.active {
    background-color: rgba(3, 50, 50, 0.1);
    border: 0;
}

/* --- Image Portfolio Grid Styling using CSS Grid --- */

.portfolio-grid { /* Renamed */
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    grid-auto-rows: minmax(200px, auto);
    gap: 0;
}

/* Mobile adaptation: 2 columns */
@media (max-width: 768px) {
    .portfolio-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Tablet adaptation: 3 columns */
@media (min-width: 769px) and (max-width: 1024px) {
    .portfolio-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}


.portfolio-item { /* Renamed */
    overflow: hidden;
    position: relative;
    opacity: 1;
    transform: scale(1);
    transition: opacity 0.4s ease, transform 0.4s ease;
    cursor: pointer;
}

/* State for hidden items by jQuery */
.portfolio-item.hidden { /* Renamed */
    opacity: 0;
    height: 0;
    padding: 0;
    margin: 0;
    border: 0;
    transform: scale(0.8);
    pointer-events: none;
    display: none;
}


.portfolio-item img { /* Renamed */
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

/* Style the '+' overlay */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: rgba(0, 0, 0, 0.3);
    color: white;
    font-size: 40px;
    opacity: 0;
    transition: opacity 0.3s;
}

.portfolio-item:hover .overlay { /* Renamed */
    opacity: 1;
}