/* =====================================================================
   ISDTDE — Shared Design System
   One stylesheet for the whole site (society hubs + conference pages).
   Light/dark theme, modern, accessible, responsive.
   ===================================================================== */

:root{
  /* Brand palette — Direction B: deep teal + warm gold (contrast-tested) */
  --brand-950:#0a2e2a;
  --brand-900:#0d3f39;
  --brand-800:#0f5950;
  --brand-700:#0f766e;
  --brand-600:#14b8a6;
  --accent-600:#b45309;   /* warm gold for text/accents on light surfaces */
  --accent-500:#f59e0b;   /* bright gold for accents on dark surfaces */

  /* Cluster colour-coding (matches submission portal) */
  --indigo-700:#4f46e5;   /* ICDTDE / winter — text on light */
  --indigo-600:#6366f1;   /* ICDTDE / winter — buttons */
  --indigo-300:#a5b4fc;   /* ICDTDE / winter — text on dark */

  --font-sans:"Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-serif:"Playfair Display", Georgia, "Times New Roman", serif;

  /* Light theme surfaces */
  --bg:#f5f8f7;
  --bg-soft:#e9f1ef;
  --panel:#ffffff;
  --panel-2:#f7faf9;
  --text:#13211f;
  --muted:#52605c;
  --border:#dde6e3;
  --ring: 0 0 0 3px rgba(15,118,110,.30);

  --radius:16px;
  --radius-sm:10px;
  --radius-pill:999px;
  --shadow-sm:0 1px 2px rgba(16,24,40,.06), 0 1px 3px rgba(16,24,40,.05);
  --shadow:0 10px 30px rgba(16,24,40,.08);
  --shadow-lg:0 24px 60px rgba(16,24,40,.14);
  --max:1140px;

  /* single flat navy hero — no gradient, no glow */
  --grad-hero: #0b2545;
}

:root[data-theme="dark"]{
  --bg:#0a1413;
  --bg-soft:#0e1c1a;
  --panel:#101d1b;
  --panel-2:#0e1817;
  --text:#e6f0ee;
  --muted:#93a39f;
  --border:#1f2d2a;
  --accent-600:#fbbf24;   /* gold reads brighter on dark surfaces */
  --shadow-sm:0 1px 2px rgba(0,0,0,.4);
  --shadow:0 12px 34px rgba(0,0,0,.45);
  --shadow-lg:0 28px 70px rgba(0,0,0,.55);
}

*{ box-sizing:border-box; }
html{ scroll-behavior:smooth; -webkit-text-size-adjust:100%; }
body{
  margin:0;
  font-family: var(--font-sans);
  color:var(--text);
  background:var(--bg);
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img{ max-width:100%; display:block; }
a{ color:var(--brand-700); text-decoration:none; }
a:hover{ text-decoration:underline; }
h1,h2,h3,h4{ line-height:1.2; margin:0 0 .5em; letter-spacing:-.01em; font-weight:750; }
/* Display headings use a refined serif (matches the submission portal) */
h1,h2{ font-family:var(--font-serif); font-weight:700; letter-spacing:0; }
h1{ font-size:clamp(2rem, 4.2vw, 3.1rem); }
h2{ font-size:clamp(1.5rem, 2.6vw, 2.1rem); }
p{ margin:0 0 1rem; }
:root[data-theme="dark"] a{ color:#5eead4; }

.container{ width:100%; max-width:var(--max); margin:0 auto; padding:0 20px; }
.muted{ color:var(--muted); }
.hide-sm{ }

.sr-only{ position:absolute; width:1px; height:1px; padding:0; margin:-1px; overflow:hidden; clip:rect(0 0 0 0); white-space:nowrap; border:0; }
.skip-link{ position:absolute; left:-9999px; top:auto; }
.skip-link:focus{
  left:16px; top:16px; z-index:3000; padding:.6rem .9rem; background:var(--panel);
  border:1px solid var(--border); border-radius:var(--radius-pill); box-shadow:var(--shadow); outline:none;
}

/* ---------- Top bar ---------- */
.topbar{ background:var(--panel); border-bottom:1px solid var(--border); }
.topbar__inner{ display:flex; align-items:center; justify-content:space-between; gap:12px; padding:.5rem 0; flex-wrap:wrap; }
.pill{
  display:inline-flex; align-items:center; gap:.4rem; font-size:.78rem; font-weight:600;
  color:var(--brand-700); background:linear-gradient(90deg, rgba(15,118,110,.10), rgba(180,83,9,.10));
  border:1px solid var(--border); padding:.32rem .7rem; border-radius:var(--radius-pill);
}
:root[data-theme="dark"] .pill{ color:#5eead4; }
.topbar__left{ display:flex; align-items:center; gap:8px; }
.topbar__right{ display:flex; align-items:center; gap:8px; flex-wrap:wrap; }

/* ---------- Buttons ---------- */
.btn{
  --btn-bg:var(--brand-700); --btn-fg:#fff; --btn-bd:var(--brand-700);
  display:inline-flex; align-items:center; justify-content:center; gap:.5rem;
  font-weight:600; font-size:.94rem; line-height:1.1; cursor:pointer;
  padding:.72rem 1.25rem; border-radius:10px;
  background:var(--btn-bg); color:var(--btn-fg); border:1px solid var(--btn-bd);
  transition:transform .1s ease, box-shadow .15s ease, background .15s ease, border-color .15s ease, color .15s ease;
  text-decoration:none; white-space:nowrap;
}
.btn:hover{ text-decoration:none; transform:translateY(-1px); }
.btn:active{ transform:translateY(0) scale(.985); }
.btn:focus-visible{ outline:none; box-shadow:var(--ring); }
.btn--sm{ padding:.5rem .85rem; font-size:.85rem; border-radius:8px; }

/* Solid / primary — soft shadow for affordance */
.btn--primary{ --btn-bg:var(--brand-700); --btn-fg:#fff; --btn-bd:var(--brand-700);
  box-shadow:0 1px 2px rgba(11,37,69,.18); }
.btn--primary:hover{ --btn-bg:var(--brand-800); --btn-bd:var(--brand-800); box-shadow:0 6px 16px rgba(15,118,110,.28); }

/* Secondary — soft filled, clearly a button */
.btn--secondary{ --btn-bg:var(--panel); --btn-fg:var(--brand-700); --btn-bd:var(--border); box-shadow:var(--shadow-sm); }
.btn--secondary:hover{ --btn-bg:var(--bg-soft); --btn-bd:color-mix(in srgb, var(--brand-700) 35%, var(--border)); }
:root[data-theme="dark"] .btn--secondary{ --btn-fg:#5eead4; }

.btn--ghost{ --btn-bg:transparent; --btn-fg:var(--text); --btn-bd:var(--border); }
.btn--ghost:hover{ --btn-bg:var(--bg-soft); }
.btn--invert{ --btn-bg:#fff; --btn-fg:var(--brand-800); --btn-bd:#fff; box-shadow:0 1px 2px rgba(0,0,0,.12); }
.btn--invert:hover{ --btn-bg:#eaf2ff; --btn-bd:#eaf2ff; }
.btn--ghostInvert{ --btn-bg:transparent; --btn-fg:#fff; --btn-bd:rgba(255,255,255,.6); }
.btn--ghostInvert:hover{ --btn-bg:rgba(255,255,255,.14); }
.btn--indigo{ --btn-bg:var(--indigo-600); --btn-fg:#fff; --btn-bd:var(--indigo-600); }
.btn--indigo:hover{ --btn-bg:var(--indigo-700); --btn-bd:var(--indigo-700); }
.icon{ display:inline-flex; }

/* ---------- Status / cluster badges (match submission portal) ---------- */
.badge{ display:inline-flex; align-items:center; gap:.4rem; font-size:.72rem; font-weight:700;
  text-transform:uppercase; letter-spacing:.05em; padding:.3rem .7rem; border-radius:var(--radius-pill); line-height:1; }
.badge::before{ content:""; width:.5rem; height:.5rem; border-radius:50%; background:currentColor; opacity:.9; }
.badge--gold{ background:#fcebc4; color:#8a5a06; }
.badge--gold::before{ display:none; }
.badge--open{ background:#dcfce7; color:#15803d; }
.badge--closed{ background:var(--bg-soft); color:var(--muted); border:1px solid var(--border); }
.badge--indigo{ background:#e7e8fd; color:#4338ca; }
.badge--indigo::before{ display:none; }
:root[data-theme="dark"] .badge--gold{ background:rgba(245,158,11,.18); color:#fcd34d; }
:root[data-theme="dark"] .badge--open{ background:rgba(22,163,74,.20); color:#86efac; }
:root[data-theme="dark"] .badge--indigo{ background:rgba(99,102,241,.22); color:#c7d2fe; }

/* ---------- Header / Nav ---------- */
.header{ position:sticky; top:0; z-index:1500; background:color-mix(in srgb, var(--panel) 88%, transparent); backdrop-filter:saturate(140%) blur(10px); border-bottom:1px solid var(--border); }
.header__inner{ display:flex; align-items:center; justify-content:space-between; gap:14px; padding:.7rem 0; }
.brand{ display:flex; align-items:center; gap:.7rem; color:var(--text); }
.brand:hover{ text-decoration:none; }
.brand__logo{ height:42px; width:auto; object-fit:contain; }
.brand__text{ display:flex; flex-direction:column; line-height:1.2; }
.brand__name{ font-weight:800; letter-spacing:.05em; font-size:1.02rem; }
.brand__tag{ font-size:.74rem; color:var(--muted); max-width:34ch; }
.nav{ display:flex; align-items:center; }
.nav__menu{ display:flex; align-items:center; gap:2px; }
.nav__menu a{ color:var(--text); padding:.5rem .72rem; border-radius:var(--radius-pill); font-size:.93rem; font-weight:550; }
.nav__menu a:hover{ background:var(--bg-soft); text-decoration:none; }
.nav__menu a:focus-visible{ outline:none; box-shadow:var(--ring); }
.nav__cta{ background:var(--brand-700); color:#fff !important; }
.nav__cta:hover{ background:var(--brand-800) !important; }
.nav__toggle{ display:none; width:42px; height:38px; border:1px solid var(--border); background:var(--panel); border-radius:var(--radius-sm); cursor:pointer; position:relative; }
.nav__toggleBars, .nav__toggleBars::before, .nav__toggleBars::after{ content:""; position:absolute; left:50%; top:50%; transform:translate(-50%,-50%); width:18px; height:2px; background:var(--text); border-radius:2px; transition:.2s; }
.nav__toggleBars::before{ transform:translate(-50%,-7px); }
.nav__toggleBars::after{ transform:translate(-50%,5px); }

/* ---------- Hero ---------- */
.hero{ position:relative; color:#fff; overflow:hidden; background:var(--grad-hero); }
.hero__inner{ position:relative; z-index:2; display:grid; grid-template-columns:1.25fr .85fr; gap:36px; align-items:center; padding:64px 20px 72px; }
.hero h1{ color:#fff; }
.hero .lead{ font-size:1.12rem; color:rgba(255,255,255,.92); max-width:60ch; }
.hero__cta{ display:flex; gap:12px; flex-wrap:wrap; margin:6px 0 26px; }
/* On the dark hero, secondary/ghost buttons must be light, not teal-on-dark */
.hero .btn--secondary, .hero .btn--ghost{ --btn-bg:rgba(255,255,255,.08); --btn-fg:#fff; --btn-bd:rgba(255,255,255,.65); }
.hero .btn--secondary:hover, .hero .btn--ghost:hover{ --btn-bg:rgba(255,255,255,.18); --btn-bd:#fff; }
.hero__stats{ display:flex; gap:14px; flex-wrap:wrap; }
.stat{ background:rgba(0,0,0,.20); border:1px solid rgba(255,255,255,.22); border-radius:var(--radius-sm); padding:.7rem 1rem; min-width:120px; }
.stat__k{ font-size:1.5rem; font-weight:800; }
.stat__v{ font-size:.8rem; color:rgba(255,255,255,.85); }
.hero__content{ min-width:0; }
.hero__card{ min-width:0; }
.cluster{ margin:2px 0; }
.hero__bg{ display:none; }

/* frosted card in hero — solid dark fill so white text is always legible
   (does NOT depend on backdrop-filter support) */
.card.card--glass{ background:rgba(6,30,27,.55); border:1px solid rgba(255,255,255,.16); color:#fff; box-shadow:var(--shadow-lg); }
.card--glass .h3{ color:#fff; }
.card--glass .link{ color:#8fe6d8; font-weight:700; }
.card--glass .link:hover{ color:#bff3ea; }
.cluster__title{ font-size:.72rem; text-transform:uppercase; letter-spacing:.08em; color:var(--accent-600); font-weight:700; }
.card--glass .cluster__title{ color:#fcd34d; }
.cluster__name{ font-size:1.25rem; font-weight:800; margin:.1rem 0 .2rem; }
/* Cluster colour-coding — summer = teal, winter = indigo (matches portal) */
.cluster--summer .cluster__name{ color:var(--brand-700); }
.cluster--winter .cluster__name{ color:var(--indigo-700); }
.card.card--glass .cluster--summer .cluster__name{ color:#5eead4; }
.card.card--glass .cluster--winter .cluster__name{ color:#a5b4fc; }
.cluster__desc{ font-size:.92rem; opacity:.9; margin:0 0 .4rem; }
.divider{ height:1px; background:var(--border); margin:.9rem 0; }
.card--glass .divider{ background:rgba(255,255,255,.2); }
.note{ font-size:.88rem; opacity:.92; }
.h3{ font-size:1.05rem; }

/* ---------- Inner-page hero (navy band) ---------- */
.pagehero{ background:var(--grad-hero); color:#fff; padding:48px 0 40px; }
.pagehero__eyebrow{ display:inline-block; font-size:.74rem; font-weight:700; text-transform:uppercase;
  letter-spacing:.1em; color:#8fe6d8; margin-bottom:10px; }
.pagehero h1{ color:#fff; margin:0 0 12px; }
.pagehero__lead{ color:rgba(255,255,255,.92); font-size:1.08rem; max-width:80ch; margin:0; }

/* ---------- Sections ---------- */
.section{ padding:64px 0; }
.section__header{ max-width:70ch; margin:0 auto 34px; text-align:center; }
.section--accent{ background:var(--grad-hero); color:#fff; }
.link{ font-weight:650; color:var(--brand-700); }
:root[data-theme="dark"] .link{ color:#5eead4; }

/* ---------- Grid & Cards ---------- */
.grid{ display:grid; gap:20px; }
.grid--2{ grid-template-columns:repeat(2, 1fr); }
.grid--3{ grid-template-columns:repeat(3, 1fr); }
.card{
  background:var(--panel); border:1px solid var(--border); border-radius:var(--radius);
  padding:24px; box-shadow:var(--shadow-sm); transition:transform .15s ease, box-shadow .15s ease, border-color .15s ease;
}
.section .grid .card:hover{ transform:translateY(-3px); box-shadow:var(--shadow); border-color:color-mix(in srgb, var(--brand-700) 30%, var(--border)); }
.card h3{ font-size:1.15rem; }

/* ---------- CTA band ---------- */
.ctaBand{ display:flex; align-items:center; justify-content:space-between; gap:24px; flex-wrap:wrap; }
.ctaBand__title{ color:#fff; margin-bottom:.3rem; }
.ctaBand__text{ color:rgba(255,255,255,.9); max-width:60ch; margin:0; }
.ctaBand__actions{ display:flex; gap:12px; flex-wrap:wrap; }

/* ---------- Footer ---------- */
.footer{ background:var(--brand-950); color:#c7d2e8; border-top:1px solid rgba(255,255,255,.06); }
.footer a{ color:#dbe6fb; }
.footer__inner{ display:grid; grid-template-columns:1.2fr 2fr; gap:28px; padding:48px 20px 28px; }
.footer__brand{ display:flex; gap:12px; align-items:center; }
.footer__logo{ height:46px; width:auto; }
.footer__name{ font-weight:800; letter-spacing:.05em; }
.footer__muted{ color:#8ea0c2; font-size:.85rem; }
.footer__cols{ display:grid; grid-template-columns:repeat(3,1fr); gap:20px; }
.footer__title{ font-weight:700; font-size:.78rem; text-transform:uppercase; letter-spacing:.08em; color:#9fb2d6; margin-bottom:8px; }
.footer__col a{ display:block; padding:.18rem 0; font-size:.92rem; }
.footer__bottom{ display:flex; align-items:center; justify-content:space-between; gap:12px; flex-wrap:wrap; padding:16px 20px 28px; border-top:1px solid rgba(255,255,255,.08); font-size:.84rem; color:#9fb2d6; }

/* ---------- Conference logo in cards ---------- */
.conf-logo{ height:46px; width:auto; max-width:100%; object-fit:contain; object-position:left center; margin:0 0 14px; }

/* ---------- Chips (tag links) ---------- */
.chips{ display:flex; flex-wrap:wrap; gap:8px; }
.chip{ display:inline-flex; align-items:center; gap:6px; padding:.36rem .72rem; border-radius:var(--radius-pill);
  border:1px solid var(--border); background:var(--panel-2); font-size:.82rem; font-weight:600; color:var(--text);
  transition:border-color .15s ease, background .15s ease, transform .1s ease; }
a.chip:hover{ border-color:var(--brand-700); background:var(--bg-soft); text-decoration:none; transform:translateY(-1px); }
.chip__dot{ width:.5rem; height:.5rem; border-radius:50%; background:var(--brand-700); }
.cluster--winter .chip__dot{ background:var(--indigo-600); }

/* Center a lone last card in a 3-up grid (desktop only) */
.grid--3 > .span-center{ grid-column:2; }
@media (max-width:980px){ .grid--3 > .span-center{ grid-column:auto; } }

/* ---------- Book covers ---------- */
.book-cover{ display:block; width:150px; margin:0 auto 16px; border-radius:8px; overflow:hidden;
  box-shadow:var(--shadow); border:1px solid var(--border);
  transition:transform .15s ease, box-shadow .15s ease; background:var(--bg-soft); }
.book-cover:hover{ transform:translateY(-3px); box-shadow:var(--shadow-lg); }
.book-cover img{ width:100%; height:auto; display:block; }

/* ---------- People / avatars ---------- */
.person{ text-align:center; }
.avatar{ position:relative; width:108px; height:108px; margin:0 auto 12px; border-radius:50%;
  overflow:hidden; display:flex; align-items:center; justify-content:center;
  background:linear-gradient(135deg, var(--brand-800), var(--brand-700));
  border:3px solid var(--panel); box-shadow:var(--shadow); }
.avatar__initials{ color:#fff; font-weight:700; font-size:1.7rem; letter-spacing:.04em; }
.avatar img{ position:absolute; inset:0; width:100%; height:100%; object-fit:cover; object-position:center top; }
.person .badge{ margin-bottom:8px; }
.person h3{ margin:8px 0 4px; }

/* ---------- Tables ---------- */
.table-wrap{ overflow-x:auto; border:1px solid var(--border); border-radius:var(--radius); }
table.table{ width:100%; border-collapse:collapse; font-size:.92rem; background:var(--panel); }
table.table th, table.table td{ text-align:left; padding:.6rem .8rem; border-bottom:1px solid var(--border); vertical-align:top; }
table.table thead th{ position:sticky; top:0; background:var(--bg-soft); font-weight:700; color:var(--text); white-space:nowrap; }
table.table tbody tr:last-child td{ border-bottom:none; }
table.table tbody tr:hover{ background:var(--bg-soft); }

/* ---------- Forms ---------- */
.form{ display:flex; flex-direction:column; gap:14px; margin-top:8px; }
.field{ display:flex; flex-direction:column; gap:6px; }
.field > span{ font-size:.85rem; font-weight:600; color:var(--text); }
.field input, .field select, .field textarea{
  font:inherit; color:var(--text); background:var(--panel-2); border:1px solid var(--border);
  border-radius:10px; padding:.6rem .75rem; width:100%; transition:border-color .15s ease, box-shadow .15s ease;
}
.field input:focus, .field select:focus, .field textarea:focus{ outline:none; border-color:var(--brand-700); box-shadow:var(--ring); }
.field textarea{ resize:vertical; }

/* ---------- Numbered steps ---------- */
ol.steps{ list-style:none; counter-reset:step; margin:14px 0 0; padding:0; display:flex; flex-direction:column; gap:14px; }
ol.steps li{ counter-increment:step; position:relative; padding-left:46px; }
ol.steps li::before{
  content:counter(step); position:absolute; left:0; top:0; width:32px; height:32px;
  display:flex; align-items:center; justify-content:center; border-radius:50%;
  background:var(--brand-700); color:#fff; font-weight:700; font-size:.9rem;
}

/* ---------- Trust strip (logos / numbers) ---------- */
.trust{ background:var(--panel); border-top:1px solid var(--border); border-bottom:1px solid var(--border); }
.trust__inner{ display:flex; align-items:center; justify-content:center; gap:42px; flex-wrap:wrap; padding:22px 20px; }
.trust__item{ text-align:center; }
.trust__k{ font-size:1.6rem; font-weight:800; color:var(--brand-700); }
:root[data-theme="dark"] .trust__k{ color:#5eead4; }
.trust__v{ font-size:.82rem; color:var(--muted); }

/* ---------- Responsive ---------- */
@media (max-width: 980px){
  .hero__inner{ grid-template-columns:1fr; gap:26px; padding:48px 20px 56px; }
  .grid--3{ grid-template-columns:1fr; }
  .grid--2{ grid-template-columns:1fr; }
  .footer__inner{ grid-template-columns:1fr; }
}
@media (max-width: 820px){
  .nav__toggle{ display:inline-flex; }
  .nav__menu{
    position:absolute; left:0; right:0; top:100%; flex-direction:column; align-items:stretch;
    gap:2px; background:var(--panel); border-bottom:1px solid var(--border); padding:10px 16px 16px;
    box-shadow:var(--shadow); display:none;
  }
  .nav__menu.is-open{ display:flex; }
  .nav{ position:static; }
  .header__inner{ position:relative; }
  .footer__cols{ grid-template-columns:1fr 1fr; }
}
@media (max-width: 560px){
  .hide-sm{ display:none; }
  .brand__tag{