/* ==========================================================================
   CUST 天文协会 — main.css
   Components: chrome, hero, cards, gallery, timeline, footer, lightbox.
   ========================================================================== */

/* ============================== site chrome ============================== */

.site-nav {
  position: sticky;
  top: 0;
  z-index: 90;
  border-bottom: 1px solid transparent;
  background: transparent;
  transition: background var(--t-base), border-color var(--t-base),
    box-shadow var(--t-base), backdrop-filter var(--t-base);
}

.site-nav.is-stuck {
  background: var(--nav-bg);
  backdrop-filter: blur(16px) saturate(1.5);
  border-bottom-color: var(--border);
  box-shadow: var(--shadow-1);
}

.nav-inner {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-height: var(--nav-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  margin-inline-end: auto;
  text-decoration: none;
  color: var(--text);
}

.brand:hover {
  color: var(--text);
}

/* The real club badge (image/aaclogo1.png): transparent artwork inset on the
   brand-gradient tile. Dark mode inverts it, which keeps the mark's contrast
   against the tile without shipping a second image. */
.brand__mark {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 42px;
  height: 42px;
  border-radius: 13px;
  background: var(--grad-brand);
  box-shadow: var(--shadow-brand);
  transition: transform var(--t-base), box-shadow var(--t-base);
}

.brand__mark img {
  width: 34px;
  height: 34px;
  object-fit: contain;
  transition: filter var(--t-base);
}

:root[data-theme="dark"] .brand__mark img {
  filter: invert(1) hue-rotate(180deg);
}

:root[data-theme="dark"] .brand__mark {
  box-shadow: 0 0 0 1px rgba(180, 205, 255, 0.32), var(--shadow-brand);
}

.brand:hover .brand__mark {
  transform: rotate(-6deg) scale(1.05);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand__name {
  font-family: var(--font-display);
  font-size: 1.03rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  font-weight: 600;
  letter-spacing: 0.19em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.15rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-link {
  position: relative;
  display: block;
  padding: 0.5rem 0.85rem;
  border-radius: var(--r-pill);
  font-size: 0.94rem;
  font-weight: 500;
  color: var(--text-soft);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--t-fast), background var(--t-fast);
}

.nav-link:hover {
  color: var(--text);
  background: color-mix(in srgb, var(--brand) 12%, transparent);
}

.nav-link[aria-current="page"] {
  color: var(--brand-strong);
  background: var(--brand-soft);
  font-weight: 600;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* -- theme toggle -- */

.theme-toggle {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 2px;
  flex: 0 0 auto;
  padding: 4px;
  border: 1px solid var(--border);
  border-radius: var(--r-pill);
  background: var(--surface-glass);
  backdrop-filter: blur(10px);
  cursor: pointer;
  transition: border-color var(--t-base), background var(--t-base);
}

.theme-toggle:hover {
  border-color: var(--border-strong);
}

.theme-toggle__thumb {
  position: absolute;
  top: 4px;
  left: 4px;
  width: calc(50% - 4px);
  height: calc(100% - 8px);
  border-radius: var(--r-pill);
  background: var(--grad-brand);
  box-shadow: var(--shadow-brand);
  transition: transform var(--t-base);
}

:root[data-theme="dark"] .theme-toggle__thumb {
  transform: translateX(100%);
}

.theme-toggle__opt {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: var(--r-pill);
  color: var(--text-muted);
  transition: color var(--t-base);
}

.theme-toggle[data-active="light"] .theme-toggle__opt:first-of-type,
.theme-toggle[data-active="dark"] .theme-toggle__opt:last-of-type {
  color: var(--text-on-brand);
}

.theme-toggle__opt svg {
  width: 17px;
  height: 17px;
}

.nav-toggle {
  display: none;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface-glass);
  backdrop-filter: blur(10px);
  cursor: pointer;
  transition: border-color var(--t-base), background var(--t-base);
}

.nav-toggle:hover {
  border-color: var(--border-strong);
}

.nav-toggle__bars {
  position: relative;
  width: 19px;
  height: 13px;
}

.nav-toggle__bars span {
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  border-radius: 2px;
  background: var(--text);
  transition: transform var(--t-base), opacity var(--t-fast), width var(--t-base);
}

.nav-toggle__bars span:nth-child(1) { top: 0; }
.nav-toggle__bars span:nth-child(2) { top: 5.5px; }
.nav-toggle__bars span:nth-child(3) { top: 11px; width: 70%; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1) {
  transform: translateY(5.5px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3) {
  width: 100%;
  transform: translateY(-5.5px) rotate(-45deg);
}

/* scroll progress hairline */
.scroll-progress {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  z-index: 95;
  width: 100%;
  height: 2px;
  transform: scaleX(var(--progress, 0));
  transform-origin: 0 50%;
  background: var(--grad-brand);
  pointer-events: none;
}

/* ============================== hero ==================================== */

.hero {
  position: relative;
  isolation: isolate;
  display: grid;
  align-items: center;
  min-height: min(94dvh, 900px);
  margin-top: calc(var(--nav-h) * -1);
  padding-block: calc(var(--nav-h) + clamp(2.5rem, 7vw, 6rem)) clamp(3rem, 8vw, 6rem);
  overflow: hidden;
  background-color: var(--bg-tint);
}

/* The club lockup as a backdrop. A fixed plate (min(560px, 42%)) keeps the
   artwork from scaling up into the headline, and the lower-right corner is the
   one part of the hero that neither the copy nor the sky panel occupies.
   The two themes use colour-inverted twins with opposite blend modes, so the
   artwork composites into the gradient instead of sitting on a white plate. */
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image: var(--hero-img);
  background-repeat: no-repeat;
  /* fixed plate so the logo cannot scale up into the headline */
  background-size: min(560px, 42%) auto;
  background-position: right 5% bottom 3%;
  filter: var(--hero-filter);
  mix-blend-mode: var(--hero-blend);
  opacity: 0.34;
}

/* veil in the theme's own gradient colours, over the logo and under the stars */
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -2;
  background-image: var(--hero-veil);
  opacity: 0.94;
}

:root[data-theme="dark"] .hero::before {
  opacity: 0.38;
}

/* faint instrument-arcs / horizon glow */
.hero__aura {
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(
      ellipse 70% 48% at 78% 12%,
      color-mix(in srgb, var(--accent-2) 34%, transparent) 0%,
      transparent 65%
    ),
    radial-gradient(
      ellipse 60% 40% at 12% 82%,
      color-mix(in srgb, var(--brand) 26%, transparent) 0%,
      transparent 68%
    );
}

/* generated starfield; colour comes from the theme tokens */
.starfield {
  position: absolute;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
  opacity: 0.85;
}

:root[data-theme="dark"] .starfield {
  opacity: 1;
}

.starfield .star {
  position: absolute;
  border-radius: 50%;
  background: var(--star-color, #ffffff);
  box-shadow: 0 0 5px color-mix(in srgb, var(--star-color, #fff) 60%, transparent);
  animation-name: twinkle;
  animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
}

:root:not([data-theme="dark"]) .starfield .star {
  background: color-mix(in srgb, var(--brand) 55%, #ffffff);
  box-shadow: 0 0 5px color-mix(in srgb, var(--brand) 30%, transparent);
}

@keyframes twinkle {
  0%,
  100% {
    opacity: 0.25;
    transform: scale(0.85);
  }
  50% {
    opacity: 1;
    transform: scale(1.12);
  }
}

/* Single column now that the sky panel is gone; the measure is capped so the
   headline and lede stay readable instead of stretching across the shell. */
.hero__copy {
  max-width: 62ch;
}

.hero__title {
  font-size: clamp(2.4rem, 1.15rem + 5.3vw, 4.6rem);
  letter-spacing: -0.026em;
  line-height: 1.06;
}

.hero__title .hero__title-en {
  display: block;
  margin-top: 0.6rem;
  font-family: var(--font-mono);
  font-size: clamp(0.68rem, 0.6rem + 0.4vw, 0.84rem);
  font-weight: 600;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.hero__lede {
  max-width: 46ch;
  margin-top: 1.35rem;
  font-size: clamp(1.03rem, 0.98rem + 0.4vw, 1.2rem);
  color: var(--text-soft);
}

.hero .btn-row {
  margin-top: 2rem;
}

.hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.6rem;
  margin-top: 2.4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.9rem;
  color: var(--text-soft);
}

.hero__meta-item {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.hero__meta-item svg {
  width: 16px;
  height: 16px;
  color: var(--brand);
  flex: 0 0 auto;
}

.hero__meta strong {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--text);
}

/* ============================== stats =================================== */

.stat-band {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1px;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--border);
  box-shadow: var(--shadow-1);
}

.stat {
  padding: clamp(1.25rem, 3vw, 1.9rem);
  background: var(--grad-panel);
  text-align: center;
}

.stat__num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(1.85rem, 1.3rem + 1.9vw, 2.65rem);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.stat__label {
  display: block;
  margin-top: 0.45rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

/* A full date is a longer run than a bare number, so it gets its own size to
   stay on one line inside the same grid track as the other figures. */
.stat__num--date {
  font-size: clamp(1.3rem, 1rem + 1vw, 1.75rem);
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
}

/* ============================== cards =================================== */

.grid {
  display: grid;
  gap: clamp(1rem, 2.4vw, 1.6rem);
}

.grid--2 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 300px), 1fr)); }
/* 248px keeps four columns on a 1180px shell while still wrapping gracefully */
.grid--4 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 248px), 1fr)); }

.card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  padding: clamp(1.3rem, 3vw, 1.85rem);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface-glass);
  backdrop-filter: blur(14px) saturate(1.3);
  box-shadow: var(--shadow-1);
  overflow: hidden;
  transition: transform var(--t-base), box-shadow var(--t-base),
    border-color var(--t-base);
}

.card::before {
  content: "";
  position: absolute;
  inset-inline: 0;
  inset-block-start: 0;
  height: 3px;
  background: var(--grad-brand);
  opacity: 0;
  transition: opacity var(--t-base);
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-2);
}

.card:hover::before {
  opacity: 1;
}

.card__icon {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 14px;
  background: var(--brand-soft);
  color: var(--brand-strong);
  border: 1px solid color-mix(in srgb, var(--brand) 22%, transparent);
}

.card__icon svg {
  width: 23px;
  height: 23px;
}

.card h3 {
  font-size: 1.16rem;
  font-family: var(--font-sans);
  font-weight: 700;
  letter-spacing: -0.005em;
}

.card p {
  font-size: 0.94rem;
  color: var(--text-soft);
  line-height: 1.68;
}

.card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 1rem;
  margin-top: auto;
  padding-top: 0.9rem;
  border-top: 1px dashed var(--divider);
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* A long run like "每周五 19:30 — 22:00" must be allowed to break, otherwise
   the card's min-content width widens past the grid's column track and the
   auto-fit grid drops a column. */
.card__meta span {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  min-width: 0;
  overflow-wrap: anywhere;
}

@media (max-width: 620px) {
  .card__meta {
    flex-direction: column;
    gap: 0.35rem;
  }
}

.card__meta svg {
  width: 14px;
  height: 14px;
  color: var(--brand);
}

.card--media {
  padding: 0;
  gap: 0;
}

.card--media .card__body {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  padding: clamp(1.15rem, 2.6vw, 1.6rem);
}

.card__thumb {
  position: relative;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: var(--surface-3);
}

.card__thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--t-slow);
}

/* credit line over the photo, matching the gallery's caption treatment */
.card__thumb figcaption {
  position: absolute;
  inset-inline: 0;
  inset-block-end: 0;
  padding: 1.8rem 0.85rem 0.7rem;
  background: linear-gradient(
    to top,
    color-mix(in srgb, var(--overlay) 100%, transparent) 0%,
    transparent 100%
  );
  color: #fff;
  font-size: 0.8rem;
  line-height: 1.4;
}

/* 缩略图上的地点／时间标注，样式与画廊的 .shot__meta 对齐 */
.card__thumb-meta {
  display: inline-flex;
  align-items: flex-start;
  gap: 0.3rem;
  font-size: 0.72rem;
  font-weight: 500;
  opacity: 0.86;
}

.card__thumb-meta svg {
  width: 12px;
  height: 12px;
  margin-top: 0.15em;
  flex: 0 0 auto;
}

.card--media:hover .card__thumb img {
  transform: scale(1.05);
}

/* ============================== split =================================== */

.split {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 340px), 1fr));
  gap: clamp(1.75rem, 5vw, 3.5rem);
  align-items: center;
}

.prose > * + * {
  margin-top: 1rem;
}

.prose p {
  color: var(--text-soft);
}

.prose h3 {
  font-size: 1.3rem;
}

.check-list {
  display: grid;
  gap: 0.85rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}

.check-list li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.8rem;
  align-items: start;
  font-size: 0.95rem;
  color: var(--text-soft);
}

.check-list svg {
  width: 20px;
  height: 20px;
  margin-top: 0.2rem;
  color: var(--brand);
  flex: 0 0 auto;
}

.check-list strong {
  display: block;
  color: var(--text);
  font-weight: 600;
}

/* framed photo used beside prose */
.frame {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
  background: var(--surface-3);
  box-shadow: var(--shadow-2);
}

.frame img {
  width: 100%;
}

.frame figcaption {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.3rem 1rem;
  padding: 0.8rem 1.1rem;
  border-top: 1px solid var(--border);
  background: var(--surface-glass-strong);
  backdrop-filter: blur(10px);
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* place of the shoot, marked with the same pin glyph used for 活动地点 */
.frame__place {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--text-soft);
}

.frame__place svg {
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
  color: var(--brand);
}

.frame__note {
  font-variant-numeric: tabular-nums;
}

/* ============================== gallery ================================= */

/* Two even columns. Four photographs of very different native shapes sit in a
   2x2 of identical tiles, so the grid reads as one set.
   Those shapes differ a lot (three ~3:2 landscapes plus one ~1:1.5 portrait),
   so a uniform tile has to crop. 4:3 is the measured compromise: it keeps
   99-100% of the three landscapes and 89% of the portrait, where 3:2 would
   leave the portrait only 74%. Change --shot-ratio alone to re-proportion the
   whole grid; per-photo framing is handled by object-position. */
.gallery-grid {
  --shot-ratio: 4 / 3;
  --shot-gap: clamp(0.7rem, 1.6vw, 1.25rem);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--shot-gap);
}

.shot {
  position: relative;
  display: block;
  aspect-ratio: var(--shot-ratio);
  padding: 0;
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface-3);
  overflow: hidden;
  cursor: zoom-in;
  box-shadow: var(--shadow-1);
  transition: transform var(--t-base), box-shadow var(--t-base),
    border-color var(--t-base);
}

.shot:hover {
  transform: translateY(-3px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-2);
}

/* The tile owns the size, the photo fills it; the shot's own object-position
   (set inline from the page data) decides which part survives the crop. */
.shot img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--t-slow), filter var(--t-base);
}

.shot:hover img {
  transform: scale(1.045);
}

/* Captions stay visible: they carry the photo's title, which is content rather
   than a hover nicety, and a hover-only label is unreachable on touch. The
   scrim is kept light and short so the photograph stays the subject. */
.shot__caption {
  position: absolute;
  inset-inline: 0;
  inset-block-end: 0;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 0.6rem;
  padding: 2.2rem 0.85rem 0.7rem;
  background: linear-gradient(
    to top,
    color-mix(in srgb, var(--overlay) 82%, transparent) 0%,
    color-mix(in srgb, var(--overlay) 40%, transparent) 38%,
    transparent 100%
  );
  color: #fff;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  line-height: 1.35;
}

/* caption text: title on top, place + time underneath */
.shot__text {
  display: flex;
  flex-direction: column;
  gap: 0.18rem;
  min-width: 0;
}

.shot__title {
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.shot__meta {
  display: inline-flex;
  align-items: flex-start;
  gap: 0.28rem;
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0;
  opacity: 0.82;
}

.shot__meta svg {
  width: 12px;
  height: 12px;
  margin-top: 0.15em;
  flex: 0 0 auto;
}

/* 作者署名：比拍摄地/时间再淡一档，不抢主体 */
.shot__credit {
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  opacity: 0.66;
}

/* the zoom affordance is a hover reward, not permanent furniture */
.shot__zoom {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.16);
  border: 1px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(6px);
  opacity: 0;
  transform: scale(0.9);
  transition: opacity var(--t-base), transform var(--t-base);
}

.shot:hover .shot__zoom,
.shot:focus-visible .shot__zoom {
  opacity: 1;
  transform: none;
}

@media (hover: none) {
  .shot__zoom {
    opacity: 1;
    transform: none;
  }
}

.shot__zoom svg {
  width: 15px;
  height: 15px;
}

/* a soft inner vignette so each frame reads as a mounted print */
.shot::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  border-radius: inherit;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.06),
    inset 0 -40px 60px -40px rgba(4, 8, 20, 0.5);
}

/* ------------------------- 可折叠的照片分组 ---------------------------- */

/* 用原生 <details>：可折叠、可用键盘操作，且禁用 JS 时依然能展开/收起。
   默认全部带 open，所以页面一打开就是全展开的。
   分组可能是「年份」，也可能是「星空毕业典礼」这样的专属分组。 */
.gallery-years {
  display: grid;
  gap: clamp(1.5rem, 3.5vw, 2.5rem);
}

.photo-group {
  border-top: 1px solid var(--border);
  padding-top: clamp(0.9rem, 2vw, 1.25rem);
}

.photo-group:first-child {
  border-top: 0;
  padding-top: 0;
}

.photo-group__head {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding-bottom: clamp(1rem, 2.2vw, 1.4rem);
  cursor: pointer;
  list-style: none;
  user-select: none;
  transition: color var(--t-fast);
}

/* 去掉浏览器默认的三角标记 */
.photo-group__head::-webkit-details-marker {
  display: none;
}

.photo-group__head::marker {
  content: "";
}

.photo-group__label {
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 1.05rem + 0.8vw, 1.6rem);
  font-weight: 600;
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
}

.photo-group__count {
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

.photo-group__chevron {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  margin-inline-start: auto;
  width: 26px;
  height: 26px;
  border: 1px solid var(--border);
  border-radius: 50%;
  color: var(--text-muted);
  transition: transform var(--t-base), border-color var(--t-base),
    color var(--t-base);
}

.photo-group__chevron svg {
  width: 14px;
  height: 14px;
}

/* 展开时箭头朝下 */
.photo-group[open] .photo-group__chevron {
  transform: rotate(90deg);
}

.photo-group__head:hover .photo-group__chevron {
  border-color: var(--brand);
  color: var(--brand);
}

.photo-group__head:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 4px;
  border-radius: var(--r-sm);
}

/* ============================== page header ============================= */

.page-head {
  position: relative;
  isolation: isolate;
  margin-top: calc(var(--nav-h) * -1);
  padding-block: calc(var(--nav-h) + clamp(2.25rem, 5.5vw, 4rem))
    clamp(2rem, 5vw, 3.5rem);
  background-image: var(--grad-page-head);
  border-bottom: 1px solid var(--border);
  overflow: hidden;
}

/* The same club lockup as a wash behind the page title. `contain` keeps the
   whole lockup visible, and the blend modes are inherited from the theme so
   the two modes stay paired. */
.page-head--photo::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -3;
  background-image: var(--hero-img);
  background-repeat: no-repeat;
  background-size: contain;
  background-position: var(--hero-focus);
  filter: var(--hero-filter);
  mix-blend-mode: var(--hero-blend);
  opacity: 0.32;
}

:root[data-theme="dark"] .page-head--photo::before {
  opacity: 0.4;
}

/* soften the hand-off into the page body so the header does not end on a seam */
.page-head--photo {
  --page-head-fade: color-mix(in srgb, var(--bg) 88%, transparent);
}

.page-head--photo::after {
  content: "";
  position: absolute;
  inset-inline: 0;
  inset-block-end: 0;
  height: 88px;
  z-index: -1;
  pointer-events: none;
  background: linear-gradient(
    to bottom,
    transparent 0%,
    var(--page-head-fade) 62%,
    var(--bg) 100%
  );
}

.page-head::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background: radial-gradient(
    ellipse 60% 80% at 88% 0%,
    color-mix(in srgb, var(--accent-2) 28%, transparent) 0%,
    transparent 62%
  );
}

.page-head h1 {
  font-size: clamp(2rem, 1.3rem + 3.2vw, 3.2rem);
}

.page-head .lede {
  max-width: 58ch;
  margin-top: 1rem;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.1rem;
  padding: 0;
  list-style: none;
  font-size: 0.84rem;
  color: var(--text-muted);
}

.breadcrumb li + li::before {
  content: "/";
  margin-inline-end: 0.5rem;
  opacity: 0.5;
}

.breadcrumb a {
  color: var(--text-soft);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--brand);
  text-decoration: underline;
}

/* ============================== CTA band =============================== */

.cta {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(2rem, 5vw, 3.5rem);
  border: 1px solid var(--border-strong);
  border-radius: var(--r-xl);
  background: var(--grad-panel);
  box-shadow: var(--shadow-2);
  text-align: center;
}

.cta::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: radial-gradient(
      ellipse 46% 70% at 6% 4%,
      color-mix(in srgb, var(--brand) 22%, transparent) 0%,
      transparent 64%
    ),
    radial-gradient(
      ellipse 46% 70% at 96% 96%,
      color-mix(in srgb, var(--accent-2) 20%, transparent) 0%,
      transparent 64%
    );
}

.cta h2 {
  font-size: clamp(1.6rem, 1.15rem + 2vw, 2.3rem);
}

.cta p {
  max-width: 56ch;
  margin: 0.9rem auto 0;
  color: var(--text-soft);
}

.cta .btn-row {
  justify-content: center;
  margin-top: 1.9rem;
}

/* ============================== contact ================================ */

.contact-card {
  display: flex;
  align-items: center;
  gap: 0.95rem;
  padding: 1.15rem 1.35rem;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--surface-glass);
  backdrop-filter: blur(12px);
  transition: border-color var(--t-base), transform var(--t-base);
}

.contact-card:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
}

.contact-card__icon {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: var(--brand-soft);
  color: var(--brand-strong);
}

.contact-card__icon svg {
  width: 19px;
  height: 19px;
}

.contact-card__label {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.contact-card__value {
  display: block;
  margin-top: 0.15rem;
  font-weight: 600;
  color: var(--text);
  /* email addresses and QQ numbers are long unbreakable runs, so allow a
     break anywhere rather than letting them widen the card */
  overflow-wrap: anywhere;
  word-break: break-word;
}

.contact-card a.contact-card__value {
  color: var(--brand);
  text-decoration: none;
}

.contact-card a.contact-card__value:hover {
  text-decoration: underline;
}

/* ============================== note / callout ========================= */

.note {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.9rem;
  padding: 1.1rem 1.3rem;
  border: 1px solid var(--border);
  border-inline-start: 3px solid var(--brand);
  border-radius: var(--r-sm);
  background: color-mix(in srgb, var(--brand) 7%, transparent);
  font-size: 0.9rem;
  color: var(--text-soft);
}

.note svg {
  width: 19px;
  height: 19px;
  margin-top: 0.15rem;
  color: var(--brand);
}

.note strong {
  color: var(--text);
}

/* ============================== footer ================================= */

.site-footer {
  margin-top: clamp(2.5rem, 6vw, 4.5rem);
  border-top: 1px solid var(--border);
  background-image: var(--grad-footer);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(auto-fit, minmax(140px, 1fr));
  gap: clamp(1.75rem, 4vw, 3rem);
  padding-block: clamp(2.5rem, 6vw, 3.75rem);
}

.footer-brand p {
  max-width: 34ch;
  margin-top: 1rem;
  font-size: 0.9rem;
  color: var(--text-soft);
}

.footer-col h2 {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.footer-col ul {
  margin: 0.9rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.55rem;
}

.footer-col a,
.footer-col li {
  font-size: 0.9rem;
  color: var(--text-soft);
  text-decoration: none;
}

.footer-col a:hover {
  color: var(--brand);
  text-decoration: underline;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1.5rem;
  padding-block: 1.2rem;
  border-top: 1px solid var(--border);
  font-size: 0.82rem;
  color: var(--text-muted);
}

.footer-bottom p {
  margin: 0;
}

/* 备案号：底栏最右侧一项，与其余小字同级 */
.footer-icp {
  color: inherit;
  text-decoration: none;
  letter-spacing: 0.02em;
  border-bottom: 1px dashed color-mix(in srgb, currentColor 55%, transparent);
  padding-bottom: 1px;
}

.footer-icp:hover {
  color: var(--text-soft);
  border-bottom-style: solid;
}

/* 页脚的授权说明：独立一行，比底栏那排小字更显眼一点 */
.footer-legal {
  margin: 0;
  padding-block: 1.1rem;
  border-top: 1px solid var(--border);
  font-size: 0.79rem;
  line-height: 1.7;
  color: var(--text-muted);
}

.footer-legal a {
  color: var(--text-soft);
  text-decoration: underline;
  text-decoration-color: color-mix(in srgb, var(--brand) 45%, transparent);
  text-underline-offset: 0.2em;
}

.footer-legal a:hover {
  color: var(--brand);
  text-decoration-color: currentColor;
}

/* 画廊里置于作品之前的「使用说明」，给一点呼吸 */
.note--usage {
  margin-bottom: clamp(1.25rem, 3vw, 2rem);
}

/* ============================== back-to-top ============================ */

.to-top {
  position: fixed;
  inset-block-end: 1.4rem;
  inset-inline-end: 1.4rem;
  z-index: 80;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--surface-glass-strong);
  backdrop-filter: blur(12px);
  color: var(--text);
  box-shadow: var(--shadow-2);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity var(--t-base), transform var(--t-base),
    visibility var(--t-base), border-color var(--t-base);
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.to-top:hover {
  border-color: var(--brand);
  color: var(--brand);
}

.to-top svg {
  width: 19px;
  height: 19px;
}

/* ============================== lightbox =============================== */

.lightbox {
  position: fixed;
  inset: 0;
  z-index: 150;
  display: grid;
  grid-template-rows: auto 1fr auto;
  gap: 0.75rem;
  padding: clamp(0.75rem, 3vw, 1.6rem);
  background: var(--overlay);
  backdrop-filter: blur(16px) saturate(1.2);
  /* 滚轮与触摸滑动到此为止，不再传给背后的页面 */
  overscroll-behavior: contain;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--t-base), visibility var(--t-base);
}

.lightbox.is-open {
  opacity: 1;
  visibility: visible;
}

.lightbox__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  color: #fff;
}

.lightbox__counter {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  opacity: 0.78;
}

.lightbox__close,
.lightbox__nav {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  cursor: pointer;
  backdrop-filter: blur(8px);
  transition: background var(--t-fast), transform var(--t-fast);
}

.lightbox__close:hover,
.lightbox__nav:hover {
  background: rgba(255, 255, 255, 0.24);
  transform: scale(1.06);
}

.lightbox__close svg,
.lightbox__nav svg {
  width: 19px;
  height: 19px;
}

/* 用 flex 而不是 grid 居中图片：grid 项的百分比 max-height 是按「轨道高度」
   解析的，轨道会被图片自身撑大，等于没有约束（图片会溢出舞台、下半部分
   被挤出视口）。flex 子项的百分比按容器高度解析，才能真正把大图缩进屏内。 */
.lightbox__stage {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 0;
  min-width: 0;
  position: relative;
}

.lightbox__stage img {
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
  border-radius: var(--r-md);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.55);
}

.lightbox__nav--prev { position: absolute; inset-inline-start: 0; }
.lightbox__nav--next { position: absolute; inset-inline-end: 0; }

.lightbox__foot {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: 0.35rem 1rem;
  text-align: center;
  color: #fff;
}

.lightbox__title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
}

.lightbox__desc {
  font-size: 0.85rem;
  opacity: 0.72;
}

/* ============================== misc =================================== */

.kbd {
  padding: 0.1rem 0.42rem;
  border: 1px solid var(--border-strong);
  border-bottom-width: 2px;
  border-radius: 6px;
  background: var(--surface-2);
  font-family: var(--font-mono);
  font-size: 0.78em;
  color: var(--text-soft);
}

.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 1.75rem; }
.mt-3 { margin-top: 2.5rem; }
.mb-2 { margin-bottom: 1.75rem; }

/* ============================== responsive ============================= */

@media (max-width: 1000px) {
  .footer-grid {
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
  }
}

@media (max-width: 860px) {
  :root {
    --nav-h: 60px;
  }

  .nav-toggle {
    display: grid;
  }

  .nav-menu {
    position: absolute;
    inset-inline: var(--gutter);
    inset-block-start: calc(100% + 0.5rem);
    flex-direction: column;
    align-items: stretch;
    gap: 0.2rem;
    padding: 0.6rem;
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    background: var(--surface-glass-strong);
    backdrop-filter: blur(20px) saturate(1.4);
    box-shadow: var(--shadow-3);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity var(--t-base), transform var(--t-base),
      visibility var(--t-base);
  }

  .nav-menu.is-open {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .nav-link {
    padding: 0.72rem 1rem;
    font-size: 1rem;
  }

  .site-nav {
    position: sticky;
  }

  .nav-inner {
    position: relative;
  }

  .hero {
    min-height: auto;
  }

  /* the column is narrow here, so the backdrop shrinks and drops lower to
     stay clear of the headline */
  .hero::before {
    background-size: min(380px, 58%) auto;
    background-position: right 3% bottom 2%;
  }

  /* one column on narrow screens; the tiles keep the same ratio, so the
     gallery stays a single evenly-spaced column of full-width photographs */
  .gallery-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 560px) {
  .brand__sub {
    display: none;
  }

  .hero__meta {
    gap: 0.6rem 1.2rem;
  }

  /* two columns instead of auto-fit, which could not shrink below 150px */
  .stat-band {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .stat {
    padding: 1.1rem 0.7rem;
  }

  .btn {
    width: 100%;
  }

  .btn-row {
    flex-direction: column;
    align-items: stretch;
  }

  .lightbox__nav--prev { inset-inline-start: -0.4rem; }
  .lightbox__nav--next { inset-inline-end: -0.4rem; }

  .to-top {
    inset-block-end: 1rem;
    inset-inline-end: 1rem;
  }
}

/* ============================== notice dialog ========================== */

/* 站点公告，用原生 <dialog>：焦点限制与 Esc 关闭由浏览器负责。
   默认不显示，只有 JS 调 showModal() 才出现，因此禁用 JS 时它不会挡住内容。 */
.notice {
  width: calc(100% - 2rem);
  max-width: 34rem;
  margin: auto;
  padding: 0;
  border: 1px solid var(--border-strong);
  border-radius: var(--r-xl);
  background: var(--surface-glass-strong);
  backdrop-filter: blur(20px) saturate(1.35);
  box-shadow: var(--shadow-3);
  color: var(--text);
  overflow: hidden;
}

.notice::backdrop {
  background: rgba(4, 7, 16, 0.62);
  backdrop-filter: blur(4px);
}

.notice__inner {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  padding: clamp(1.3rem, 3.5vw, 1.9rem);
}

.notice__title {
  font-size: clamp(1.25rem, 1.05rem + 0.7vw, 1.55rem);
  line-height: 1.25;
}

.notice__body {
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--text-soft);
}

.notice__links {
  display: grid;
  gap: 0.5rem;
  margin: 1rem 0 0;
  padding: 0;
  list-style: none;
}

.notice__links li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.3rem 0.6rem;
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: color-mix(in srgb, var(--brand) 6%, transparent);
}

.notice__links-label {
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--text-muted);
}

.notice__links a {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px dashed color-mix(in srgb, var(--brand) 55%, transparent);
}

.notice__links a:hover {
  border-bottom-style: solid;
}

.notice__actions {
  display: flex;
  justify-content: flex-end;
  margin: 0;
}

/* 弹窗打开时锁住背景滚动 */
:root[data-notice-open] {
  overflow: hidden;
}

/* 灯箱打开时同样锁住 <html>。不能只锁 body：<html> 上有 overflow-x: clip，
   按规范会阻止 body 的 overflow 传播到视口，那样只锁 body 是无效的。
   页面已设 scrollbar-gutter: stable，因此锁定时不会出现横向抖动。 */
:root[data-lightbox-open] {
  overflow: hidden;
}

/* ============================== print ================================== */

@media print {
  .site-nav,
  .to-top,
  .lightbox,
  .notice,
  .scroll-progress,
  .hero::before,
  .hero__aura {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
  }

  .card {
    box-shadow: none;
    border-color: #ccc;
  }
}