/* =================================================
   SECTION NAV
   Mobile-first: base = 320px, progressive enhancement via min-width
   ================================================= */
.portfolio-section-nav {
    position: sticky;
    top: var(--navbar-height);
    z-index: 40;
    background: rgba(250, 248, 245, 0.96);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--tortora);
}

.portfolio-section-nav__list {
    display: flex;
    align-items: stretch;
    gap: 0;
    margin: 0;
    padding: 0;
    list-style: none;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
}

.portfolio-section-nav__item {
    flex: 1 1 0;
    min-width: max-content;
}

.portfolio-section-nav__btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    width: 100%;
    padding: 0.85rem var(--space-4);
    border: none;
    border-bottom: 2px solid transparent;
    background: transparent;
    font-family: var(--font-sans);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text-light);
    cursor: pointer;
    transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
    white-space: nowrap;
}

.portfolio-section-nav__btn:hover {
    color: var(--nero);
    background: rgba(10, 10, 10, 0.02);
}

.portfolio-section-nav__btn.is-active {
    color: var(--nero);
    border-bottom-color: var(--magenta);
}

.portfolio-section-nav__count {
    font-size: 0.68rem;
    font-weight: 500;
    letter-spacing: 0.04em;
    color: var(--grigio);
    padding: 0.1rem 0.4rem;
    border: 1px solid var(--tortora);
}

.portfolio-section-nav__btn.is-active .portfolio-section-nav__count {
    color: var(--magenta);
    border-color: rgba(194, 24, 91, 0.25);
}

/* ==================== GALLERY GRID ==================== */
.portfolio-gallery {
    padding: var(--space-8) 0 var(--space-12);
    background: var(--avorio);
    min-height: 50vh;
}

.portfolio-section-panel[hidden] {
    display: none !important;
}

.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-3);
    max-width: 1440px;
    margin: 0 auto;
}

.portfolio-grid__item {
    display: block;
    width: 100%;
    padding: 0;
    border: 1px solid var(--tortora);
    background: var(--charcoal);
    cursor: pointer;
    overflow: hidden;
    text-align: left;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.portfolio-grid__item:hover {
    border-color: var(--nero);
    box-shadow: var(--shadow-md);
}

.portfolio-grid__item:focus-visible {
    outline: 2px solid var(--magenta);
    outline-offset: 2px;
}

.portfolio-grid__frame {
    position: relative;
    display: block;
    aspect-ratio: 4 / 5;
    overflow: hidden;
}

.portfolio-grid__img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    transition: transform 0.35s var(--ease-out-expo);
}

.portfolio-grid__item:hover .portfolio-grid__img {
    transform: scale(1.03);
}

.portfolio-grid__zoom {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(10, 10, 10, 0.28);
    color: var(--avorio);
    font-size: 1rem;
    opacity: 0;
    transition: opacity 0.2s ease;
    pointer-events: none;
}

.portfolio-grid__item:hover .portfolio-grid__zoom {
    opacity: 1;
}

.portfolio-empty {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
    min-height: 280px;
    text-align: center;
    color: var(--text-light);
    border: 1px solid var(--tortora);
    background: var(--color-surface-alt);
}

.portfolio-empty i {
    font-size: 1.5rem;
    opacity: 0.45;
}

.portfolio-empty p {
    margin: 0;
    font-family: var(--font-sans);
    font-size: var(--text-sm);
}

/* =================================================
   RESPONSIVE — min-width progressive enhancement
   ================================================= */
@media (min-width: 768px) {
    .portfolio-section-nav__btn {
        padding: var(--space-4) var(--space-5);
        font-size: 0.78rem;
    }

    .portfolio-grid {
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
        gap: var(--space-4);
    }
}

@media (min-width: 1280px) {
    .portfolio-grid {
        grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
        gap: var(--space-5);
    }
}