/* --------------------------------------------------------------------------
   6. SCREENSHOT GALLERY SECTION
   --------------------------------------------------------------------------
*/

.gallery-section {
  padding-block: var(--space-24);
  background-color: var(--color-bg-page);
  position: relative;
}

/* Thin gradient separator from the subjects section above */
.gallery-section::before {
  content: '';
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(
    to right,
    transparent,
    var(--color-border),
    transparent
  );
}

/* ── Grid ────────────────────────────────────────────────────────────────── */

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}

@media (max-width: 1024px) {
  .gallery-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 480px) {
  .gallery-grid {
    grid-template-columns: 1fr;
  }
}


/* ── Thumbnail ───────────────────────────────────────────────────────────── */

.gallery-thumb {
  position: relative;
  display: block;
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  border: 1px solid var(--color-border);
  background-color: var(--color-bg-surface);

  /* Fade-in via JS adding .gallery-thumb--visible */
  opacity: 0;
  transform: translateY(12px);
  transition:
    opacity var(--transition-slow),
    transform var(--transition-slow),
    border-color var(--transition-base),
    box-shadow var(--transition-base);
}

/* JS adds this class when thumbnail enters viewport */
.gallery-thumb--visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger the fade-in per card */
.gallery-thumb:nth-child(1) { transition-delay: 0ms; }
.gallery-thumb:nth-child(2) { transition-delay: 60ms; }
.gallery-thumb:nth-child(3) { transition-delay: 120ms; }
.gallery-thumb:nth-child(4) { transition-delay: 180ms; }
.gallery-thumb:nth-child(5) { transition-delay: 240ms; }
.gallery-thumb:nth-child(6) { transition-delay: 300ms; }

.gallery-thumb:hover {
  border-color: var(--color-border-light);
  box-shadow: var(--shadow-lg);
}

/* Per-subject accent on hover */
.gallery-thumb[data-subject="mathematics"]:hover {
  border-color: rgba(0, 229, 255, 0.35);
  box-shadow: var(--shadow-lg), 0 0 24px rgba(0, 229, 255, 0.08);
}

.gallery-thumb[data-subject="physics"]:hover {
  border-color: rgba(139, 92, 246, 0.35);
  box-shadow: var(--shadow-lg), 0 0 24px rgba(139, 92, 246, 0.08);
}

.gallery-thumb[data-subject="computer-science"]:hover {
  border-color: rgba(16, 185, 129, 0.35);
  box-shadow: var(--shadow-lg), 0 0 24px rgba(16, 185, 129, 0.08);
}

/* Make the whole card keyboard-focusable with a visible ring */
.gallery-thumb:focus-visible {
  outline: 2px solid var(--color-accent-primary);
  outline-offset: 3px;
}


/* ── Thumbnail image ─────────────────────────────────────────────────────── */

.gallery-thumb__img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  display: block;
  background-color: var(--color-bg-surface-alt);
  transition: transform var(--transition-slow);
}

.gallery-thumb:hover .gallery-thumb__img {
  transform: scale(1.025);
}


/* ── Overlay — shown on hover, reveals zoom icon + subject tag ───────────── */

.gallery-thumb__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to top,
    rgba(11, 15, 20, 0.88) 0%,
    rgba(11, 15, 20, 0.2) 50%,
    transparent 100%
  );
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: var(--space-5);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.gallery-thumb:hover .gallery-thumb__overlay,
.gallery-thumb:focus-visible .gallery-thumb__overlay {
  opacity: 1;
}

/* Subject pill inside the overlay */
.gallery-thumb__subject {
  display: inline-flex;
  align-self: flex-start;
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border-radius: var(--radius-full);
  margin-bottom: var(--space-2);
  backdrop-filter: blur(8px);
}

.gallery-thumb[data-subject="mathematics"] .gallery-thumb__subject {
  background-color: var(--color-accent-primary-bg);
  color: var(--color-accent-primary);
  border: 1px solid rgba(0, 229, 255, 0.2);
}

.gallery-thumb[data-subject="physics"] .gallery-thumb__subject {
  background-color: var(--color-accent-secondary-bg);
  color: var(--color-accent-secondary);
  border: 1px solid rgba(139, 92, 246, 0.2);
}

.gallery-thumb[data-subject="computer-science"] .gallery-thumb__subject {
  background-color: var(--palette-green-muted);
  color: var(--palette-green);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

/* Caption text inside overlay */
.gallery-thumb__caption {
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  color: var(--color-text-primary);
  line-height: var(--leading-snug);
}


/* ── Zoom icon ───────────────────────────────────────────────────────────── */

.gallery-thumb__zoom {
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
  background-color: rgba(11, 15, 20, 0.7);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--transition-base);
  font-size: 14px;
  color: var(--color-text-primary);
  border: 1px solid var(--color-border-light);
}

.gallery-thumb:hover .gallery-thumb__zoom,
.gallery-thumb:focus-visible .gallery-thumb__zoom {
  opacity: 1;
}


/* ── Placeholder (no real screenshots yet) ───────────────────────────────── */

.gallery-thumb__placeholder {
  width: 100%;
  aspect-ratio: 4 / 3;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  background: linear-gradient(
    135deg,
    var(--color-bg-surface) 0%,
    var(--color-bg-surface-alt) 100%
  );
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.gallery-thumb__placeholder-icon {
  font-size: var(--text-3xl);
  opacity: 0.4;
}

.gallery-thumb__placeholder-label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  letter-spacing: 0.04em;
}


/* --------------------------------------------------------------------------
   7. LIGHTBOX
   --------------------------------------------------------------------------
   Full-screen overlay that shows the selected screenshot at full size.
   Opened/closed by gallery.js — .lightbox--open class drives visibility.
   -------------------------------------------------------------------------- */

.lightbox {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal);
  display: flex;
  align-items: center;
  justify-content: center;

  /* Hidden by default */
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}

/* Visible state — JS adds this class */
.lightbox--open {
  opacity: 1;
  pointer-events: auto;
}


/* ── Backdrop ────────────────────────────────────────────────────────────── */

.lightbox__backdrop {
  position: absolute;
  inset: 0;
  background-color: rgba(7, 9, 12, 0.92);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  cursor: pointer;
}


/* ── Inner container — sits above the backdrop ───────────────────────────── */

.lightbox__inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: min(90vw, 1100px);
  max-height: 90vh;
  width: 100%;

  /* Slide-up entrance when opening */
  transform: translateY(8px);
  transition: transform var(--transition-base);
}

.lightbox--open .lightbox__inner {
  transform: translateY(0);
}


/* ── Image ───────────────────────────────────────────────────────────────── */

.lightbox__img-wrap {
  position: relative;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-xl);
  overflow: hidden;
  border: 1px solid var(--color-border-light);
  background-color: var(--color-bg-surface);
  box-shadow: var(--shadow-xl);

  /* Maintain readable height, allow natural width */
  max-height: 70vh;
}

.lightbox__img {
  display: block;
  max-width: 100%;
  max-height: 70vh;
  object-fit: contain;
  transition: opacity var(--transition-fast);
}

/* Fade during image swap */
.lightbox__img--loading {
  opacity: 0.3;
}


/* ── Caption bar below the image ─────────────────────────────────────────── */

.lightbox__meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  margin-top: var(--space-4);
  padding: 0 var(--space-2);
  gap: var(--space-4);
}

.lightbox__caption {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--leading-snug);
  flex: 1;
}

.lightbox__count {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  white-space: nowrap;
  flex-shrink: 0;
}


/* ── Navigation buttons (prev/next) ──────────────────────────────────────── */

.lightbox__btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 2;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background-color: rgba(11, 15, 20, 0.8);
  border: 1px solid var(--color-border-light);
  color: var(--color-text-primary);
  font-size: var(--text-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    transform var(--transition-fast);
  backdrop-filter: blur(8px);
}

.lightbox__btn:hover {
  background-color: rgba(0, 229, 255, 0.12);
  border-color: rgba(0, 229, 255, 0.3);
}

.lightbox__btn--prev {
  left: calc(-1 * var(--space-16));
}

.lightbox__btn--next {
  right: calc(-1 * var(--space-16));
}

/* On smaller screens where there's no room outside the image */
@media (max-width: 1100px) {
  .lightbox__btn--prev { left: var(--space-3); }
  .lightbox__btn--next { right: var(--space-3); }
}


/* ── Close button — top-right corner ────────────────────────────────────── */

.lightbox__close {
  position: fixed;
  top: var(--space-6);
  right: var(--space-6);
  z-index: var(--z-modal);
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background-color: rgba(11, 15, 20, 0.8);
  border: 1px solid var(--color-border-light);
  color: var(--color-text-primary);
  font-size: var(--text-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    transform var(--transition-fast);
  backdrop-filter: blur(8px);
  line-height: 1;
}

.lightbox__close:hover {
  background-color: rgba(239, 68, 68, 0.15);
  border-color: rgba(239, 68, 68, 0.4);
  transform: scale(1.05);
}

@media (max-width: 768px) {
  .lightbox__close {
    top: var(--space-4);
    right: var(--space-4);
  }
}


/* ── Reduced motion — no transitions ────────────────────────────────────── */

@media (prefers-reduced-motion: reduce) {
  .gallery-thumb {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .gallery-thumb__img {
    transition: none;
  }

  .lightbox,
  .lightbox__inner {
    transition: none;
  }
}