/* ==========================================================================
   OPM66 — base stylesheet
   Practical substitute for Gilroy: 'Poppins' (geometric sans, similar
   weight range). Swap the @import + --font-display value once Gilroy
   is licensed for this domain.
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700;800&display=swap');

:root {
  /* Color */
  --color-ink:        #0e0e0f;   /* near-black, header/footer/nav */
  --color-ink-soft:   #1c1c1e;
  --color-crimson:    #A51C30;   /* accent — HBS-style crimson */
  --color-crimson-dark: #7d1524;
  --color-paper:      #ffffff;
  --color-paper-off:  #f6f5f3;
  --color-line:       #e4e2de;
  --color-text:       #1c1c1c;
  --color-text-muted: #6b6b6b;
  --color-text-on-ink: rgba(255,255,255,0.92);
  --color-text-on-ink-muted: rgba(255,255,255,0.62);

  /* Type */
  --font-display: 'Poppins', system-ui, -apple-system, sans-serif;
  --font-body: 'Poppins', system-ui, -apple-system, sans-serif;

  /* Layout */
  --max-width: 1280px;
  --radius: 10px;
  --nav-height: 84px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-paper);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  margin: 0 0 0.5em;
  line-height: 1.15;
}
p { margin: 0 0 1em; max-width: 68ch; }
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}
:focus-visible {
  outline: 2px solid var(--color-crimson);
  outline-offset: 2px;
}
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}

/* ---------------------------- Buttons ---------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 30px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn-light { background: var(--color-paper); color: var(--color-ink); }
.btn-light:hover { background: #eee; }
.btn-crimson { background: var(--color-crimson); color: #fff; }
.btn-crimson:hover { background: var(--color-crimson-dark); }
.btn-outline { background: transparent; border-color: currentColor; }

/* ---------------------------- Nav ---------------------------- */
.site-nav {
  position: absolute;
  top: 0; left: 0; right: 0;
  z-index: 50;
  height: var(--nav-height);
  display: flex;
  align-items: center;
}
.site-nav.is-solid {
  position: sticky;
  background: var(--color-ink);
}
.site-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: 0.02em;
}
.brand img { height: 38px; width: auto; }
.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
  margin: 0; padding: 0;
}
.nav-links a {
  color: var(--color-text-on-ink-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.15s ease;
}
.nav-links a:hover, .nav-links a.is-active { color: #fff; }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: #fff;
  font-size: 1.6rem;
  cursor: pointer;
}
@media (max-width: 860px) {
  .nav-links {
    position: fixed;
    top: var(--nav-height); left: 0; right: 0;
    background: var(--color-ink);
    flex-direction: column;
    gap: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.25s ease;
  }
  .nav-links.is-open { max-height: 420px; }
  .nav-links a { display: block; padding: 16px 24px; border-top: 1px solid rgba(255,255,255,0.08); }
  .nav-toggle { display: block; }
}

/* -------------------------- Location switcher -------------------------- */
.loc-switch { position: relative; }
.loc-selected {
  display: flex; align-items: center; gap: 8px;
  color: #fff; font-weight: 600; cursor: pointer;
  padding: 8px 14px; border: 1px solid rgba(255,255,255,0.25); border-radius: 999px;
}
.loc-options {
  position: absolute; top: calc(100% + 8px); left: 0;
  background: var(--color-ink-soft);
  border-radius: 10px;
  min-width: 220px;
  box-shadow: 0 12px 30px rgba(0,0,0,0.35);
  display: none;
  overflow: hidden;
  z-index: 60;
}
.loc-switch.is-open .loc-options { display: block; }
.loc-item {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 16px; color: var(--color-text-on-ink);
  font-size: 0.9rem;
}
.loc-item:hover { background: rgba(255,255,255,0.06); }

/* ---------------------------- Hero ---------------------------- */
.hero {
  position: relative;
  min-height: 640px;
  display: flex;
  align-items: flex-end;
  color: #fff;
  background: linear-gradient(180deg, rgba(0,0,0,0.35), rgba(0,0,0,0.6)), var(--color-ink) center/cover no-repeat;
}
.hero.hero-image { background-image: linear-gradient(180deg, rgba(0,0,0,0.25), rgba(0,0,0,0.65)), var(--hero-img); background-size: cover; background-position: center; }
.hero-inner { padding: 100px 0 72px; width: 100%; }
.hero-eyebrow { color: var(--color-text-on-ink-muted); font-weight: 600; letter-spacing: 0.08em; margin-bottom: 10px; }
.hero h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); }
.hero .dates { font-size: 1.2rem; color: var(--color-text-on-ink-muted); margin-bottom: 28px; }
.hero-sidebar {
  position: absolute; top: var(--nav-height); left: 0; padding: 32px 24px;
  color: #fff; z-index: 5;
}
.hero-sidebar h4 { font-size: 0.75rem; letter-spacing: 0.12em; color: var(--color-text-on-ink-muted); text-transform: uppercase; margin: 18px 0 10px; }
.hero-sidebar ul { list-style: none; margin: 0; padding: 0; }
.hero-sidebar li a {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 0; font-weight: 600;
}
.hero-sidebar .flag { font-size: 1.2rem; }

/* ---------------------------- Sections ---------------------------- */
.section { padding: 88px 0; }
.section-alt { background: var(--color-paper-off); }
.section-dark { background: var(--color-ink); color: var(--color-text-on-ink); }
.section-head { max-width: 720px; margin: 0 auto 48px; text-align: center; }
.section-head h2 { font-size: clamp(1.8rem, 4vw, 2.6rem); }
.section-head p { margin: 0 auto; color: var(--color-text-muted); }

/* ---------------------------- Timeline (About) ---------------------------- */
.timeline { position: relative; max-width: 980px; margin: 0 auto; }
.timeline::before {
  content: ''; position: absolute; left: 50%; top: 0; bottom: 0;
  width: 2px; background: var(--color-line); transform: translateX(-50%);
}
.timeline-item { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; margin-bottom: 56px; position: relative; }
.timeline-item .photo img { border-radius: var(--radius); box-shadow: 0 12px 30px rgba(0,0,0,0.12); }
.timeline-item .copy h3 { font-size: 1.4rem; }
.timeline-item .copy .meta { color: var(--color-crimson); font-weight: 600; }
.timeline-item.flip .photo { order: 2; }
.timeline-item.flip .copy { order: 1; text-align: right; }
.timeline-dot {
  position: absolute; left: 50%; top: 50%; width: 14px; height: 14px;
  background: var(--color-crimson); border: 3px solid #fff; border-radius: 50%;
  transform: translate(-50%, -50%);
}
@media (max-width: 760px) {
  .timeline::before { left: 10px; }
  .timeline-item, .timeline-item.flip { grid-template-columns: 1fr; text-align: left !important; padding-left: 34px; }
  .timeline-item.flip .photo, .timeline-item.flip .copy { order: unset; }
  .timeline-dot { left: 10px; }
}

/* ---------------------------- Reunion cards ---------------------------- */
.reunion-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 28px; }
@media (max-width: 760px) { .reunion-grid { grid-template-columns: 1fr; } }
.reunion-card {
  position: relative; border-radius: var(--radius); overflow: hidden;
  min-height: 380px; color: #fff;
  background: linear-gradient(180deg, rgba(0,0,0,0.05) 40%, rgba(0,0,0,0.85)), var(--card-img) center/cover no-repeat;
  display: flex; flex-direction: column; justify-content: space-between;
}
.reunion-card .badge {
  align-self: flex-start; margin: 20px; padding: 8px 16px;
  background: rgba(0,0,0,0.55); border-radius: 8px; font-weight: 700;
}
.reunion-card .body { padding: 24px; }
.reunion-card .body h3 { margin-bottom: 4px; }
.reunion-card .body .loc { color: var(--color-text-on-ink-muted); font-size: 0.9rem; }
.reunion-card .menu { list-style: none; margin: 16px 0 0; padding: 0; }
.reunion-card .menu li a { display: block; padding: 4px 0; font-size: 0.9rem; font-weight: 600; }

/* ---------------------------- Reunion sub-nav tabs ---------------------------- */
.reunion-tabs { display: flex; gap: 8px; flex-wrap: wrap; margin: 32px 0 48px; }
.reunion-tabs a {
  padding: 10px 20px; border-radius: 999px; border: 1px solid var(--color-line);
  font-weight: 600; font-size: 0.9rem; color: var(--color-text-muted);
}
.reunion-tabs a.is-active { background: var(--color-ink); color: #fff; border-color: var(--color-ink); }

/* ---------------------------- Agenda ---------------------------- */
.agenda-day { display: grid; grid-template-columns: 160px 1fr; gap: 32px; padding: 32px 0; border-top: 1px solid var(--color-line); }
.agenda-day .when { color: var(--color-crimson); font-weight: 700; }
.agenda-day .when .day-num { display: block; font-size: 2rem; color: var(--color-ink); }
@media (max-width: 640px) { .agenda-day { grid-template-columns: 1fr; gap: 8px; } }

/* ---------------------------- Speakers ---------------------------- */
.speaker-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 28px; }
.speaker-card img { border-radius: var(--radius); aspect-ratio: 1/1; object-fit: cover; margin-bottom: 14px; background: var(--color-paper-off); }
.speaker-card h4 { margin-bottom: 2px; }
.speaker-card .role { color: var(--color-text-muted); font-size: 0.9rem; margin-bottom: 8px; }

/* ---------------------------- Giveback progress ---------------------------- */
.progress-track { height: 10px; background: var(--color-line); border-radius: 999px; overflow: hidden; margin: 14px 0; }
.progress-fill { height: 100%; background: var(--color-crimson); }

/* ---------------------------- Feedback form ---------------------------- */
.feedback-form { display: grid; gap: 16px; max-width: 560px; }
.feedback-form .row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 560px) { .feedback-form .row { grid-template-columns: 1fr; } }
.feedback-form input, .feedback-form textarea {
  width: 100%; padding: 14px 16px; border-radius: 8px; border: 1px solid var(--color-line);
  font-family: var(--font-body); font-size: 0.95rem; background: var(--color-paper);
}
.feedback-form label.checkbox { display: flex; align-items: center; gap: 8px; font-size: 0.9rem; color: var(--color-text-muted); }
.form-note { font-size: 0.85rem; padding: 12px 16px; border-radius: 8px; margin-bottom: 8px; }
.form-note.success { background: #eaf7ee; color: #1e6b34; }
.form-note.error { background: #fbeaea; color: #a3272c; }

/* ---------------------------- Stats ---------------------------- */
.stats-summary { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; margin-bottom: 40px; }
@media (max-width: 760px) { .stats-summary { grid-template-columns: repeat(2, 1fr); } }
.stat-box { border: 1px solid var(--color-line); border-radius: var(--radius); padding: 24px; text-align: center; }
.stat-box .num { font-size: 2.2rem; font-weight: 800; color: var(--color-crimson); }
.stat-box .label { color: var(--color-text-muted); font-size: 0.9rem; }

.stats-controls { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin-bottom: 24px; }
.stats-search { flex: 1 1 240px; padding: 12px 16px; border-radius: 999px; border: 1px solid var(--color-line); }
.az-bar { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 20px; }
.az-bar button {
  width: 30px; height: 30px; border-radius: 6px; border: 1px solid var(--color-line);
  background: #fff; font-weight: 600; font-size: 0.8rem; cursor: pointer;
}
.az-bar button.is-active { background: var(--color-ink); color: #fff; border-color: var(--color-ink); }
.tag-pills { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 32px; }
.tag-pills button {
  padding: 8px 14px; border-radius: 999px; border: 1px solid var(--color-line);
  background: #fff; font-size: 0.82rem; cursor: pointer;
}
.tag-pills button.is-active { background: var(--color-crimson); color: #fff; border-color: var(--color-crimson); }

.member-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 24px; }
.member-card { text-align: center; }
.member-card .avatar {
  width: 96px; height: 96px; border-radius: 50%; margin: 0 auto 10px;
  background: var(--color-paper-off); display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 1.4rem; color: var(--color-text-muted); overflow: hidden;
}
.member-card .avatar img { width: 100%; height: 100%; object-fit: cover; }
.member-card .name { font-weight: 600; font-size: 0.92rem; }
.member-card .meta { font-size: 0.8rem; color: var(--color-text-muted); }
.member-empty { text-align: center; color: var(--color-text-muted); padding: 40px 0; grid-column: 1/-1; }

/* ---------------------------- Footer ---------------------------- */
.site-footer { background: var(--color-ink); color: var(--color-text-on-ink); padding: 64px 0 0; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 48px; padding-bottom: 48px; border-bottom: 1px solid rgba(255,255,255,0.08); }
@media (max-width: 760px) { .footer-grid { grid-template-columns: 1fr; } }
.footer-grid h4 { color: #fff; font-size: 0.95rem; margin-bottom: 16px; }
.footer-grid ul { list-style: none; margin: 0; padding: 0; }
.footer-grid li { margin-bottom: 10px; }
.footer-grid a { color: var(--color-text-on-ink-muted); }
.footer-grid a:hover { color: #fff; }
.footer-bar { background: var(--color-crimson); text-align: center; padding: 16px; font-size: 0.85rem; margin-top: 24px; }

/* ---------------------------- Utility ---------------------------- */
.text-center { text-align: center; }
.mt-0 { margin-top: 0; }

/* ---------------------------- Motion / polish ---------------------------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }

.site-nav {
  transition: background 0.25s ease, height 0.25s ease, box-shadow 0.25s ease;
}
.site-nav.is-scrolled:not(.is-solid) {
  position: fixed;
  background: rgba(14, 14, 15, 0.9);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  height: 68px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.25);
}
.site-nav.is-solid.is-scrolled {
  background: rgba(14, 14, 15, 0.96);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  height: 68px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.25);
}

.hero.hero-image { background-attachment: fixed; }
@media (max-width: 760px) { .hero.hero-image { background-attachment: scroll; } } /* fixed bg is unreliable on mobile Safari */

.reunion-card, .member-card, .speaker-card, .stat-box, .timeline-item .photo img {
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.reunion-card:hover { transform: translateY(-6px); box-shadow: 0 20px 40px rgba(0,0,0,0.25); }
.member-card:hover .avatar, .speaker-card:hover img { transform: scale(1.05); box-shadow: 0 10px 24px rgba(0,0,0,0.15); }
.member-card .avatar, .speaker-card img { transition: transform 0.25s ease, box-shadow 0.25s ease; }
.stat-box:hover { transform: translateY(-4px); box-shadow: 0 14px 28px rgba(0,0,0,0.08); }
.timeline-item:hover .photo img { transform: scale(1.02); box-shadow: 0 18px 36px rgba(0,0,0,0.18); }

img[loading="lazy"] { background: var(--color-paper-off); }

/* ---------------------------- Lightbox ---------------------------- */
.lightbox-overlay {
  position: fixed; inset: 0; background: rgba(0,0,0,0.92);
  display: none; align-items: center; justify-content: center;
  z-index: 200; padding: 40px;
}
.lightbox-overlay.is-open { display: flex; }
.lightbox-overlay img { max-width: 90vw; max-height: 85vh; border-radius: 6px; }
.lightbox-close, .lightbox-prev, .lightbox-next {
  position: absolute; background: rgba(255,255,255,0.1); color: #fff;
  border: none; border-radius: 50%; width: 44px; height: 44px;
  font-size: 1.3rem; cursor: pointer; display: flex; align-items: center; justify-content: center;
}
.lightbox-close:hover, .lightbox-prev:hover, .lightbox-next:hover { background: rgba(255,255,255,0.2); }
.lightbox-close { top: 24px; right: 24px; }
.lightbox-prev { left: 24px; top: 50%; transform: translateY(-50%); }
.lightbox-next { right: 24px; top: 50%; transform: translateY(-50%); }
.photo-tab-panel img { cursor: zoom-in; }

/* ---------------------------- Accessibility ---------------------------- */
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 300;
  background: #fff; color: var(--color-ink); padding: 12px 20px;
  border-radius: 0 0 8px 0; font-weight: 700;
}
.skip-link:focus { left: 0; }

/* ---------------------------- Nav search ---------------------------- */
.nav-search input {
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 999px;
  color: #fff;
  padding: 7px 14px;
  font-size: 0.85rem;
  width: 140px;
}
.nav-search input::placeholder { color: rgba(255,255,255,0.55); }
.nav-search input:focus { outline: none; border-color: rgba(255,255,255,0.5); width: 180px; }
@media (max-width: 860px) {
  .nav-search { padding: 12px 24px; }
  .nav-search input { width: 100%; }
}