/* ── 麵包屑 ─────────────────────────────────────────── */
.er-breadcrumb { padding: 1.25rem 0 0; }
.er-breadcrumb ol {
  display: flex; flex-wrap: wrap; gap: .2rem .5rem;
  list-style: none; padding: 0; margin: 0;
  font-size: .875rem;
}
.er-breadcrumb li { display: flex; align-items: center; color: var(--c-muted); }
.er-breadcrumb li + li::before { content: '/'; margin-right: .5rem; color: #bbb; }
.er-breadcrumb a { color: var(--c-primary); text-decoration: underline; }
.er-breadcrumb a:hover { color: var(--c-primary-dark); text-decoration: none; }
.er-breadcrumb [aria-current="page"] { color: var(--c-text); font-weight: 500; }

/* ── 內容卡片 ────────────────────────────────────────── */
.er-detail-wrap {
  background: var(--c-card);
  border-radius: var(--radius-md);
  padding: 2rem 2.5rem 2.75rem;
  box-shadow: var(--shadow-sm);
  margin: 1.5rem 0 3rem;
}

/* ── 文章標頭 ────────────────────────────────────────── */
.er-detail-header { margin-bottom: 1.75rem; }

.er-detail-tags { display: flex; flex-wrap: wrap; gap: .45rem; margin-bottom: .9rem; }
.er-tag {
  display: inline-flex; align-items: center; gap: .35em;
  font-size: .8125rem; font-weight: 600;
  padding: .25em .8em; border-radius: var(--radius-pill);
  white-space: nowrap; line-height: 1.6;
}
.er-tag--mountain { background: rgba(59,93,80,.12); color: var(--c-primary); }
.er-tag--sea      { background: rgba(30,80,140,.10); color: #1e508c; }
.er-tag--date,
.er-tag--location { background: var(--c-accent); color: #4a5e58; }

.er-detail-title {
  font-size: clamp(1.375rem, 3.5vw, 1.875rem);
  font-weight: 700; color: #1a2e26;
  margin: 0; line-height: 1.35;
}

/* ── Section 標題 ────────────────────────────────────── */
.er-section-title {
  display: flex; align-items: center; gap: .5rem;
  font-size: 1.125rem; font-weight: 700;
  color: var(--c-primary);
  border-left: 4px solid var(--c-primary);
  padding-left: .75rem;
  margin: 0 0 1.25rem;
  line-height: 1.45;
}
.er-section-title .gallery-count {
  font-size: .875rem; font-weight: 400; color: #668876;
}

hr.er-divider {
  border: none; border-top: 1px solid var(--c-border);
  margin: 2rem 0;
}

/* ── 活動說明 ────────────────────────────────────────── */
.er-detail-desc { margin-bottom: 0; }
.er-detail-desc p {
  color: var(--c-text); line-height: 1.9; margin-bottom: 1rem;
}
.er-detail-desc p:last-child { margin-bottom: 0; }

/* ── 影片 ────────────────────────────────────────────── */
.er-detail-video { margin: 0; }
.video-responsive {
  position: relative; padding-top: 56.25%;
  background: #000; border-radius: var(--radius-sm); overflow: hidden;
}
.video-responsive iframe {
  position: absolute; inset: 0;
  width: 100%; height: 100%; border: none;
}

/* ── 圖廊格線 ────────────────────────────────────────── */
.er-detail-gallery { margin: 0; }

.photo-gallery {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: .625rem;
  list-style: none; padding: 0; margin: 0;
}

.photo-item figure { margin: 0; }

.photo-btn {
  display: block; width: 100%; padding: 0;
  border: 2px solid transparent;
  background: var(--c-accent);
  cursor: pointer; overflow: hidden;
  border-radius: var(--radius-sm);
  aspect-ratio: 4 / 3;
  position: relative;
  transition: border-color var(--trans);
}
.photo-btn img {
  width: 100%; height: 100%;
  object-fit: cover; display: block;
  transition: transform .3s ease;
}
.photo-btn:hover img,
.photo-btn:focus-visible img { transform: scale(1.06); }

.photo-overlay {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  background: rgba(0,0,0,0); color: transparent;
  font-size: 1.5rem; pointer-events: none;
  transition: background var(--trans), color var(--trans);
}
.photo-btn:hover .photo-overlay,
.photo-btn:focus-visible .photo-overlay {
  background: rgba(0,0,0,.42); color: #fff;
}
.photo-btn:focus-visible {
  outline: 3px solid var(--c-focus); outline-offset: 2px;
}
.photo-btn.no-img { background: linear-gradient(135deg, #c8d3d1, var(--c-accent)); }
.photo-btn.no-img img { opacity: 0; }

.photo-item figcaption {
  font-size: .8125rem; color: var(--c-muted);
  padding: .35rem .1rem 0;
  text-align: center; line-height: 1.4;
}

/* ── 返回按鈕 ────────────────────────────────────────── */
.er-detail-back {
  margin-top: 2.5rem; padding-top: 1.5rem;
  border-top: 1px solid var(--c-border);
}
.btn-back {
  display: inline-flex; align-items: center; gap: .5rem;
  color: var(--c-primary); font-weight: 600; font-size: .9375rem;
  text-decoration: none;
  padding: .5rem 1.25rem;
  border: 2px solid var(--c-primary); border-radius: var(--radius-sm);
  transition: background var(--trans), color var(--trans);
}
.btn-back:hover { background: var(--c-primary); color: #fff; text-decoration: none; }
.btn-back:focus-visible { outline: 3px solid var(--c-focus); outline-offset: 2px; }

/* ── Lightbox ────────────────────────────────────────── */
dialog.lightbox {
  max-width: min(940px, 94vw);
  width: 100%;
  padding: 0; border: none;
  background: #111; color: #fff;
  border-radius: 10px; overflow: visible;
}
dialog.lightbox::backdrop { background: rgba(0,0,0,.88); }

.lb-inner {
  position: relative;
  display: flex; flex-direction: column; align-items: center;
  padding: 2.75rem 1.25rem 1.25rem;
  gap: .75rem;
}

.lb-close {
  position: absolute; top: .6rem; right: .75rem;
  background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.2);
  color: #fff; font-size: 1.125rem;
  width: 2.25rem; height: 2.25rem;
  border-radius: 50%; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background var(--trans);
  flex-shrink: 0;
}
.lb-close:hover { background: rgba(255,255,255,.35); }
.lb-close:focus-visible { outline: 3px solid var(--c-secondary-lt); outline-offset: 2px; }

.lb-img-wrap {
  display: flex; align-items: center; gap: .75rem; width: 100%;
}
.lb-figure {
  flex: 1; margin: 0; min-width: 0;
  display: flex; flex-direction: column; align-items: center;
}
#lb-img {
  max-width: 100%; max-height: 64vh;
  object-fit: contain; display: block;
  border-radius: 4px;
}
.lb-caption {
  font-size: .875rem; color: rgba(255,255,255,.72);
  margin-top: .6rem; text-align: center;
  min-height: 1.3em; line-height: 1.4;
}

.lb-nav {
  flex-shrink: 0;
  background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.2);
  color: #fff; font-size: 1.2rem;
  width: 2.75rem; height: 2.75rem;
  border-radius: 50%; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background var(--trans);
}
.lb-nav:hover { background: rgba(255,255,255,.35); }
.lb-nav:focus-visible { outline: 3px solid var(--c-secondary-lt); outline-offset: 2px; }

.lb-counter {
  font-size: .8125rem; color: rgba(255,255,255,.55);
  letter-spacing: .03em;
}

/* ── RWD ─────────────────────────────────────────────── */
@media (max-width: 991px) {
  .photo-gallery { grid-template-columns: repeat(3, 1fr); }
}
@media (max-width: 767px) {
  .er-detail-wrap { padding: 1.5rem 1.25rem 2rem; }
  .photo-gallery { grid-template-columns: repeat(2, 1fr); gap: .5rem; }
  .lb-nav { width: 2.25rem; height: 2.25rem; font-size: 1rem; }
  dialog.lightbox { max-width: 98vw; }
}
@media (max-width: 480px) {
  .lb-img-wrap { gap: .4rem; }
  .lb-inner { padding: 2.5rem .625rem 1rem; gap: .5rem; }
  .lb-nav { width: 2rem; height: 2rem; font-size: .9rem; }
}