:root{
  --gallery-focus: #1a73e8;
  --c1: #6363FF;
  --c2: #1BB3A7;
  --c3: #FFB246;
  --shadow1: 0 8px 22px rgba(0,0,0,.10);
  --shadow2: 0 16px 34px rgba(0,0,0,.16);
}

/* Back to top */
.back-to-top{
  font-family: "Open Sans", Arial, sans-serif;
  display:none;
  position:fixed;
  bottom:20px;
  right:20px;
  z-index:99;
  font-size:15px;
  border:none;
  background-color: var(--c1);
  color:#fff;
  cursor:pointer;
  padding:14px 16px;
  border-radius:10px;
  min-width:44px;
  min-height:44px;
  box-shadow: var(--shadow1);
}

.back-to-top:hover{ filter: brightness(.95); }

.back-to-top:focus-visible{
  outline:3px solid var(--gallery-focus);
  outline-offset:3px;
}

/* Header accent */
.act-rich{ position: relative; }
.act-rich__header{ position: relative; margin-bottom: 8px; }
.act-rich__title{ position: relative; }
.act-rich__subtitle{ font-size: 1.6rem; color: #444; }

.act-rich__title::after{
  content:"";
  display:block;
  width:min(1000px, 92%);
  height:12px;
  margin: 14px auto 0;
  margin-top: 0px;
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(99,99,255,.35), rgba(27,179,167,.25), rgba(255,178,70,.28));
}

/* Activity meta */
.act-meta{
  margin:18px auto 16px;
  max-width: 980px;
  padding: 14px 16px;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(99,99,255,.08), rgba(27,179,167,.06));
  box-shadow: var(--shadow1);
}

.act-meta__row{
  display:grid;
  grid-template-columns: 90px 1fr;
  gap: 10px;
  padding: 6px 0;
  font-size: 1.26rem;
}

.act-meta dt{ font-weight: 700; }
.act-meta dd{ margin: 0; }

@media (max-width: 576px){
  .act-meta__row{ grid-template-columns: 1fr; }
}

/* Photo grid */
.photo-grid{
  display:grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 480px));
  gap: 18px;
  align-items:start;
  margin: 14px 0 22px;
  justify-content: center;
}


.photo-card{ margin:0; }

.photo-card__btn{
  position: relative;
  display:block;
  width:100%;
  padding:0;
  border:0;
  background: transparent;
  cursor:pointer;
  border-radius: 14px;
  overflow:hidden;
  transform: translateZ(0);
  transition: transform .22s ease, box-shadow .22s ease, filter .22s ease;
  box-shadow: var(--shadow1);
}

.photo-card__btn img{
  width:100%;
  height:auto;
  display:block;
  border-radius: 14px;
  transition: transform .28s ease;
}

/* Hint label */
.photo-card__hint{
  position:absolute;
  right: 10px;
  bottom: 10px;
  padding: 6px 10px;
  border-radius: 999px;
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  background: rgba(0,0,0,.55);
  opacity: 0;
  transform: translateY(4px);
  transition: opacity .22s ease, transform .22s ease;
  pointer-events:none;
}

/* Color glow */
.photo-card__btn::before{
  content:"";
  position:absolute;
  inset:-2px;
  background: linear-gradient(120deg, rgba(99,99,255,.55), rgba(27,179,167,.45), rgba(255,178,70,.45));
  opacity:0;
  transition: opacity .22s ease;
  pointer-events:none;
}

.photo-card__btn::after{
  content:"";
  position:absolute;
  inset:0;
  background: radial-gradient(circle at 50% 68%, rgba(0,0,0,.22), rgba(0,0,0,0) 55%);
  opacity:0;
  transition: opacity .22s ease;
  pointer-events:none;
}

.photo-card__btn:hover,
.photo-card__btn:focus-visible{
  transform: translateY(-4px);
  box-shadow: var(--shadow2);
}

.photo-card__btn:hover::before,
.photo-card__btn:focus-visible::before{ opacity: 1; }

.photo-card__btn:hover::after,
.photo-card__btn:focus-visible::after{ opacity: 1; }

.photo-card__btn:hover img,
.photo-card__btn:focus-visible img{
  transform: scale(1.1);
}

.photo-card__btn:hover .photo-card__hint,
.photo-card__btn:focus-visible .photo-card__hint{
  opacity: 1;
  transform: none;
}

.photo-card__btn:focus-visible{
  outline:3px solid var(--gallery-focus);
  outline-offset: 4px;
}

.photo-card figcaption{
  margin-top: 10px;
  font-size: 16px;
  line-height: 1.4;
  text-align: center;
}

.photo-card--centered {
  max-width: 480px;
  width:100%;
  height:auto;
  margin: 0 auto;
  grid-column: 1/-1;
  text-align: center;
}

.ally-focus-ring {
  display: block;
  max-width: 820px;
  margin: 0 auto;
  border-radius: 10px;
  transform: scale(1);
  transition: transform 0.3s ease;
}

.ally-focus-ring:focus {
  outline: none;
}

.ally-focus-ring:focus-visible {
  outline: 3px solid #0000bf;
  outline-offset: 4px;
  border-radius: 12px;
}

.ally-focus-ring:focus-visible {
  box-shadow: 0 0 0 3px rgba (0, 82, 204, 0.18);
  transform: scale(1.05);
}
  
  
/* Section headings accent */
.act-rich__h, .act-rich__h3{ display: inline-block; position: relative; }
.act-rich__h::after, .act-rich__h3::after{
  content:"";
  display:block;
  height: 10px;
  margin-top: -10px;
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(99,99,255,.28), rgba(27,179,167,.22), rgba(255,178,70,.22));
}

/* Reveal on scroll */
.reveal{
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .38s ease, transform .38s ease;
}

.reveal.is-inview{
  opacity: 1;
  transform: none;
}

/* Accessible modal */
.a11y-modal{
  position: fixed;
  inset: 0;
  z-index: 2000;
}

.a11y-modal__backdrop{
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,.65);
  opacity: 0;
  transition: opacity .22s ease;
}

.a11y-modal.is-open .a11y-modal__backdrop{ opacity: 1; }

.a11y-modal__dialog{
  position: relative;
  max-width: 980px;
  margin: 6vh auto 0;
  background: #fff;
  border-radius: 14px;
  padding: 12px;
  box-shadow: 0 14px 54px rgba(0,0,0,.38);
  transform: translateY(10px) scale(.985);
  opacity: 0;
  transition: transform .22s ease, opacity .22s ease;
}

.a11y-modal.is-open .a11y-modal__dialog{
  transform: none;
  opacity: 1;
}

@media (max-width: 576px){
  .a11y-modal__dialog{ margin: 2vh 10px 0; }
}

.a11y-modal__close{
  display: inline-block;
  min-width: 44px;
  min-height: 44px;
  padding: 8px 12px;
  border-radius: 10px;
  border: 1px solid #ccc;
  background: #f8f8f8;
}

.a11y-modal__close:focus-visible,
.a11y-modal__navbtn:focus-visible{
  outline: 3px solid var(--gallery-focus);
  outline-offset: 3px;
}

.a11y-modal__figure{ margin: 12px 0 8px; }

.a11y-modal__img{
  width: 100%;
  height: auto;
  display: block;
  border-radius: 12px;
}

.a11y-modal__caption{
  margin-top: 10px;
  font-size: 16px;
}

.a11y-modal__nav{
  display:flex;
  gap: 10px;
  justify-content: flex-end;
  margin-top: 10px;
}

.a11y-modal__navbtn{
  min-width: 44px;
  min-height: 44px;
  padding: 8px 12px;
  border-radius: 10px;
  border: 1px solid #ccc;
  background: #fff;
}

/* Reduced motion: respect user preference */
@media (prefers-reduced-motion: reduce){
  .photo-card__btn,
  .photo-card__btn img,
  .photo-card__hint,
  .photo-card__btn::before,
  .photo-card__btn::after,
  .reveal,
  .a11y-modal__dialog,
  .a11y-modal__backdrop{
    transition: none !important;
  }

  .photo-card__btn:hover,
  .photo-card__btn:focus-visible{ transform: none !important; }

  .photo-card__btn:hover img,
  .photo-card__btn:focus-visible img{ transform: none !important; }

  .reveal{ opacity: 1; transform: none; }
}
/* 1) 令 dialog 永遠唔會高過視窗，並可滾動 */
.a11y-modal__dialog{
  max-height: calc(100vh - 4vh - 20px); /* 4vh 係你 margin-top 6vh 留返少少呼吸位 */
  overflow: auto;
}

/* 2) 圖片本身唔好撐爆 */
.a11y-modal__img{
  max-height: 60vh;
  object-fit: contain;
}

/* 3) caption 與按鈕保持可見與好用 */
.a11y-modal__nav{
  position: sticky;
  bottom: 0;
  background: #fff;
  padding-top: 10px;
}

.a11y-modal__counter{
  margin: 6px 0 0;
  font-size: 14px;
  color: #555;
}

.a11y-modal__thumbs{
  display: flex;
  gap: 10px;
  padding: 10px 2px 2px;
  overflow-x: auto;
  overscroll-behavior-x: contain;
  -webkit-overflow-scrolling: touch;
}

.a11y-thumb{
  flex: 0 0 auto;
  width: 72px;
  height: 54px;
  border-radius: 10px;
  border: 2px solid transparent;
  background: #fff;
  padding: 0;
}

.a11y-thumb img{
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 8px;
  display: block;
}

.a11y-thumb[aria-current="true"]{
  border-color: var(--gallery-focus);
}

.a11y-thumb:focus-visible{
  outline: 3px solid var(--gallery-focus);
  outline-offset: 3px;
}
\n\n/* --- Modal: click main image to open original size in a new tab --- */
.a11y-modal__openfull{ display:block; }
.a11y-modal__openfull .a11y-modal__img{ cursor: zoom-in; }
.a11y-modal__openfull:focus-visible{ outline: 3px solid var(--gallery-focus); outline-offset: 3px; border-radius: 12px; }


/* --- Modal: in-place 1:1 zoom & pan (no new tab) --- */
.a11y-modal__zoom{
  display: inline-block;
  min-width: 44px;
  min-height: 44px;
  padding: 8px 12px;
  margin-left: 8px;
  border-radius: 10px;
  border: 1px solid #ccc;
  background: #fff;
}

.a11y-modal__zoom:focus-visible{
  outline: 3px solid var(--gallery-focus);
  outline-offset: 3px;
}

.a11y-modal__viewport{
  width: 100%;
  max-height: 60vh;
  overflow: auto;
  border-radius: 12px;
  background: #fff;
}

.a11y-modal__viewport:focus-visible{
  outline: 3px solid var(--gallery-focus);
  outline-offset: 3px;
}

.a11y-modal__img{
  width: 100%;
  height: auto;
  display: block;
  border-radius: 12px;
  max-height: 60vh;
  object-fit: contain;
}

/* Zoom mode: show at natural size and allow panning/scrolling */
.a11y-modal.is-zoomed .a11y-modal__viewport{
  cursor: grab;
}

.a11y-modal.is-zoomed .a11y-modal__viewport.is-panning{
  cursor: grabbing;
}

.a11y-modal.is-zoomed .a11y-modal__img{
  width: auto;
  max-width: none;
  max-height: none;
  object-fit: initial;
}

@media (prefers-reduced-motion: reduce){
  .a11y-modal__viewport{ scroll-behavior: auto; }
}