:root {
  --bg: #f5f6f8;
  --surface: #ffffff;
  --surface-2: #f0f2f5;
  --border: #dde1e7;
  --text: #1c2430;
  --muted: #5d6878;
  --accent: #0f6e8c;
  --accent-strong: #0a5570;
  --accent-soft: #e2f1f6;
  --warn: #9a5b00;
  --warn-soft: #fff2dc;
  --ok: #1d7a46;
  --ok-soft: #e1f4e8;
  --danger: #b3261e;
  --hero-from: #0b3a4a;
  --hero-to: #145f78;
  --shadow: 0 1px 2px rgba(20, 30, 45, .06), 0 2px 8px rgba(20, 30, 45, .05);
  --radius: 10px;
  --f-talk: #0f6e8c;
  --f-lightning: #a15c00;
  --f-demo: #6a3fb5;
  --f-workshop: #1d7a46;
  --f-panel: #b0305a;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11151b;
    --surface: #1a2029;
    --surface-2: #222a35;
    --border: #2f3947;
    --text: #e6ebf1;
    --muted: #9aa5b4;
    --accent: #4fb6d6;
    --accent-strong: #7fcde6;
    --accent-soft: #173744;
    --warn: #f0b45a;
    --warn-soft: #3a2c14;
    --ok: #62c98e;
    --ok-soft: #173826;
    --danger: #ff8a80;
    --hero-from: #0a2a36;
    --hero-to: #0f4658;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3);
    --f-talk: #4fb6d6;
    --f-lightning: #f0b45a;
    --f-demo: #b39af0;
    --f-workshop: #62c98e;
    --f-panel: #f08aac;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.55 "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
a { color: var(--accent); }
button, input, select, textarea { font: inherit; color: inherit; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.wrap { max-width: 1240px; margin: 0 auto; padding: 0 16px; }

/* ---------- header ---------- */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 20;
}
.site-header .wrap { display: flex; align-items: center; gap: 24px; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-weight: 700; font-size: 17px; white-space: nowrap; }
.brand-mark {
  width: 30px; height: 30px; border-radius: 8px;
  background: linear-gradient(135deg, var(--hero-from), var(--accent));
  color: #fff; display: grid; place-items: center; font-size: 13px; font-weight: 800; letter-spacing: -.5px;
}
.nav { display: flex; gap: 4px; margin-left: auto; }
.nav a {
  text-decoration: none; color: var(--muted); padding: 8px 12px; border-radius: 8px; font-weight: 500; white-space: nowrap;
}
.nav a:hover { background: var(--surface-2); color: var(--text); }
.nav a[aria-current="page"] { color: var(--accent); background: var(--accent-soft); }
.nav a.cta { background: var(--accent); color: #fff; }
.nav a.cta:hover { background: var(--accent-strong); color: #fff; }
@media (prefers-color-scheme: dark) { .nav a.cta, .nav a.cta:hover { color: #0b1a20; } }

/* ---------- hero ---------- */
.hero {
  background: linear-gradient(120deg, var(--hero-from), var(--hero-to));
  color: #fff; padding: 36px 0 30px;
}
.hero h1 { margin: 0 0 6px; font-size: clamp(24px, 4vw, 34px); line-height: 1.2; letter-spacing: -.5px; }
.hero p { margin: 0; opacity: .88; max-width: 720px; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-top: 14px; font-size: 14px; opacity: .92; }
.hero-meta span::before { content: "•"; margin-right: 8px; opacity: .6; }
.hero-meta span:first-child::before { content: none; }

/* ---------- format tabs (top) ---------- */
.tabs { background: var(--surface); border-bottom: 1px solid var(--border); }
.tabs .wrap { display: flex; gap: 2px; overflow-x: auto; scrollbar-width: none; }
.tabs .wrap::-webkit-scrollbar { display: none; }
.tab {
  background: none; border: 0; border-bottom: 3px solid transparent; cursor: pointer;
  padding: 14px 14px 11px; color: var(--muted); font-weight: 600; white-space: nowrap;
}
.tab:hover { color: var(--text); }
.tab[aria-selected="true"] { color: var(--accent); border-bottom-color: var(--accent); }
.tab .count { font-weight: 500; font-size: 12px; margin-left: 4px; color: var(--muted); }

/* ---------- catalog layout ---------- */
.catalog { display: grid; grid-template-columns: 260px 1fr; gap: 24px; padding-top: 24px; padding-bottom: 60px; align-items: start; }
@media (max-width: 880px) { .catalog { grid-template-columns: 1fr; } }

.filters {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 6px 16px 16px; position: sticky; top: 76px; max-height: calc(100vh - 92px); overflow: auto;
}
@media (max-width: 880px) {
  .filters { position: static; max-height: none; display: none; }
  .filters.open { display: block; }
}
.filters-head { display: flex; justify-content: space-between; align-items: center; padding: 10px 0 4px; }
.filters-head h2 { font-size: 13px; text-transform: uppercase; letter-spacing: .06em; margin: 0; color: var(--muted); }
.link-btn { background: none; border: 0; color: var(--accent); cursor: pointer; padding: 4px 0; font-size: 13px; font-weight: 600; }
.facet { border-top: 1px solid var(--border); padding: 10px 0; }
.facet:first-of-type { border-top: 0; }
.facet summary { cursor: pointer; font-weight: 600; list-style: none; display: flex; justify-content: space-between; padding: 4px 0; }
.facet summary::-webkit-details-marker { display: none; }
.facet summary::after { content: "▾"; color: var(--muted); transition: transform .15s; }
.facet[open] summary::after { transform: rotate(180deg); }
.facet label { display: flex; align-items: center; gap: 8px; padding: 4px 0; cursor: pointer; font-size: 14px; }
.facet label .n { margin-left: auto; color: var(--muted); font-size: 12px; }
.facet input[type=checkbox] { accent-color: var(--accent); width: 16px; height: 16px; }

.toolbar { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-bottom: 14px; }
.search { flex: 1 1 260px; position: relative; }
.search input {
  width: 100%; padding: 11px 14px 11px 38px; border: 1px solid var(--border); border-radius: 8px; background: var(--surface);
}
.search svg { position: absolute; left: 12px; top: 50%; transform: translateY(-50%); color: var(--muted); }
.toolbar select, .btn-filter {
  padding: 10px 12px; border: 1px solid var(--border); border-radius: 8px; background: var(--surface); cursor: pointer;
}
.btn-filter { display: none; font-weight: 600; }
@media (max-width: 880px) { .btn-filter { display: inline-block; } }
.result-meta { color: var(--muted); font-size: 14px; margin: 0 0 12px; display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.chip {
  display: inline-flex; align-items: center; gap: 6px; background: var(--accent-soft); color: var(--accent-strong);
  border: 0; border-radius: 999px; padding: 3px 10px; font-size: 12px; font-weight: 600; cursor: pointer;
}
.chip::after { content: "×"; font-size: 14px; line-height: 1; }

/* ---------- session cards ---------- */
.sessions { display: grid; gap: 12px; }
.slot {
  font-size: 14px; font-weight: 700; color: var(--muted); margin: 14px 0 -2px; padding-bottom: 6px;
  border-bottom: 1px solid var(--border); text-transform: uppercase; letter-spacing: .04em;
}
.slot:first-child { margin-top: 0; }
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 16px 18px; display: grid; grid-template-columns: 1fr auto; gap: 4px 16px;
  border-left: 4px solid var(--fc, var(--accent));
}
.card-top { display: flex; flex-wrap: wrap; gap: 6px 10px; align-items: center; font-size: 12px; color: var(--muted); }
.badge {
  font-weight: 700; text-transform: uppercase; letter-spacing: .05em; font-size: 11px;
  color: var(--fc, var(--accent));
}
.pill { background: var(--surface-2); border-radius: 999px; padding: 2px 9px; font-size: 12px; color: var(--muted); }
.card h3 { margin: 4px 0 2px; font-size: 17px; line-height: 1.35; }
.card h3 button { all: unset; cursor: pointer; }
.card h3 button:hover { color: var(--accent); text-decoration: underline; }
.card h3 button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.speaker { color: var(--muted); font-size: 14px; }
.speaker strong { color: var(--text); font-weight: 600; }
.card .when { font-size: 13px; color: var(--muted); margin-top: 6px; display: flex; gap: 14px; flex-wrap: wrap; }
.card .abstract { grid-column: 1 / -1; color: var(--muted); font-size: 14px; margin: 6px 0 0; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.star {
  background: none; border: 1px solid var(--border); border-radius: 8px; padding: 7px 12px; cursor: pointer;
  color: var(--accent); font-weight: 600; font-size: 13px; white-space: nowrap; align-self: start;
}
.star:hover { border-color: var(--accent); color: var(--accent); }
.star[aria-pressed="true"] { background: var(--accent); border-color: var(--accent); color: #fff; }
.card[data-format="Talk"] { --fc: var(--f-talk); }
.card[data-format="Lightning Talk"] { --fc: var(--f-lightning); }
.card[data-format="Live Demo"] { --fc: var(--f-demo); }
.card[data-format="Workshop"] { --fc: var(--f-workshop); }
.card[data-format="Panel"] { --fc: var(--f-panel); }

.empty, .notice {
  background: var(--surface); border: 1px dashed var(--border); border-radius: var(--radius);
  padding: 32px; text-align: center; color: var(--muted);
}
.notice { border-style: solid; text-align: left; padding: 12px 16px; font-size: 14px; margin-bottom: 14px; background: var(--warn-soft); color: var(--warn); border-color: transparent; }

/* ---------- detail dialog ---------- */
dialog {
  border: 0; border-radius: 14px; padding: 0; width: min(720px, calc(100vw - 32px)); max-height: calc(100vh - 48px);
  background: var(--surface); color: var(--text); box-shadow: 0 20px 60px rgba(0,0,0,.3);
}
dialog::backdrop { background: rgba(10, 20, 30, .55); }
.dlg-head { padding: 22px 24px 14px; border-bottom: 1px solid var(--border); position: relative; border-top: 5px solid var(--fc, var(--accent)); }
.dlg-head h2 { margin: 6px 40px 4px 0; font-size: 22px; line-height: 1.3; }
.dlg-close { position: absolute; top: 14px; right: 14px; background: none; border: 0; font-size: 24px; cursor: pointer; color: var(--muted); width: 36px; height: 36px; border-radius: 8px; }
.dlg-close:hover { background: var(--surface-2); }
.dlg-body { padding: 18px 24px 24px; overflow: auto; }
.dlg-body h3 { font-size: 13px; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin: 18px 0 6px; }
.dlg-body p { margin: 0 0 8px; white-space: pre-line; }
.facts { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 10px; margin: 0; }
.facts div { background: var(--surface-2); border-radius: 8px; padding: 8px 12px; }
.facts dt { font-size: 12px; color: var(--muted); }
.facts dd { margin: 0; font-weight: 600; }
.tags { display: flex; flex-wrap: wrap; gap: 6px; }

/* ---------- submit page ---------- */
.form-wrap { display: grid; grid-template-columns: 1fr 300px; gap: 24px; padding-top: 24px; padding-bottom: 60px; align-items: start; }
@media (max-width: 880px) { .form-wrap { grid-template-columns: 1fr; } }
.panel { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px 24px; box-shadow: var(--shadow); }
.panel + .panel { margin-top: 16px; }
.panel h2 { margin: 0 0 4px; font-size: 18px; }
.panel .hint { color: var(--muted); font-size: 14px; margin: 0 0 16px; }
.field { margin-bottom: 16px; }
.field label, .field legend { display: block; font-weight: 600; margin-bottom: 6px; font-size: 14px; }
.field .req { color: var(--danger); }
.field small { display: block; color: var(--muted); font-size: 13px; margin-top: 4px; }
.field input[type=text], .field input[type=email], .field input[type=url], .field select, .field textarea {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border); border-radius: 8px; background: var(--surface);
}
.field textarea { min-height: 120px; resize: vertical; }
.field input:focus, .field select:focus, .field textarea:focus, .search input:focus, .toolbar select:focus {
  outline: 2px solid var(--accent); outline-offset: 0; border-color: var(--accent);
}
.field [aria-invalid="true"] { border-color: var(--danger); }
.field .err { color: var(--danger); font-size: 13px; margin-top: 4px; display: none; }
.field [aria-invalid="true"] ~ .err { display: block; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0 16px; }
@media (max-width: 600px) { .grid-2 { grid-template-columns: 1fr; } }
fieldset { border: 0; padding: 0; margin: 0; }
.choices { display: flex; flex-wrap: wrap; gap: 8px; }
.choices label { font-weight: 500; margin: 0; }
.choices input { position: absolute; opacity: 0; pointer-events: none; }
.choices span {
  display: inline-block; padding: 7px 14px; border: 1px solid var(--border); border-radius: 999px; cursor: pointer; font-size: 14px;
}
.choices input:checked + span { background: var(--accent); border-color: var(--accent); color: #fff; }
.choices input:focus-visible + span { outline: 2px solid var(--accent); outline-offset: 2px; }
.counter { float: right; font-weight: 400; color: var(--muted); font-size: 12px; }
.hp { position: absolute; left: -9999px; }
.btn {
  background: var(--accent); color: #fff; border: 0; border-radius: 8px; padding: 12px 22px; font-weight: 700; cursor: pointer;
}
.btn:hover { background: var(--accent-strong); }
.btn:disabled { opacity: .6; cursor: progress; }
@media (prefers-color-scheme: dark) {
  .btn { color: #0b1a20; }
  .choices input:checked + span, .star[aria-pressed="true"] { color: #0b1a20; }
}
.actions { display: flex; gap: 14px; align-items: center; flex-wrap: wrap; }
.aside h3 { margin: 0 0 8px; font-size: 15px; }
.aside ul { margin: 0; padding-left: 18px; color: var(--muted); font-size: 14px; }
.aside li { margin-bottom: 6px; }
.status { border-radius: 8px; padding: 14px 16px; margin-bottom: 16px; font-size: 14px; }
.status.ok { background: var(--ok-soft); color: var(--ok); }
.status.err { background: #fde7e5; color: var(--danger); }
@media (prefers-color-scheme: dark) { .status.err { background: #3b1a18; } }

.site-footer { border-top: 1px solid var(--border); color: var(--muted); font-size: 13px; padding: 20px 0 30px; }
.site-footer .wrap { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }

@media (max-width: 600px) {
  .site-header .wrap { gap: 10px; }
  .brand span:last-child { display: none; }
  .nav a { padding: 8px 9px; font-size: 14px; }
  .card { padding: 14px; grid-template-columns: 1fr; }
  .star { justify-self: start; }
}

/* ---------- landing page ---------- */
.landing-hero { padding: 72px 0 64px; }
.landing-hero h1 { font-size: clamp(32px, 6vw, 52px); margin-bottom: 14px; }
.landing-hero .lede { font-size: clamp(17px, 2.2vw, 21px); line-height: 1.5; max-width: 680px; opacity: .95; }
.eyebrow { text-transform: uppercase; letter-spacing: .08em; font-size: 13px; font-weight: 600; margin: 0 0 10px; opacity: .8; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.hero-actions .btn { text-decoration: none; display: inline-block; }
.btn-light, .btn-light:hover { background: #fff; color: var(--hero-from); }
.btn-light:hover { opacity: .92; }
.btn-outline { background: transparent; color: #fff; box-shadow: inset 0 0 0 2px rgba(255,255,255,.75); }
.btn-outline:hover { background: rgba(255,255,255,.12); }
@media (prefers-color-scheme: dark) {
  .btn-light, .btn-light:hover { color: #0b1a20; }
  .btn-outline, .btn-outline:hover { color: #fff; }
}
.landing { padding-top: 40px; padding-bottom: 64px; display: grid; gap: 40px; }
.section-title { font-size: 22px; margin: 0 0 16px; }
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
@media (max-width: 760px) { .steps { grid-template-columns: 1fr; } }
.panel + .panel.step { margin-top: 0; }
.step h3 { margin: 10px 0 6px; font-size: 17px; }
.step p { margin: 0; color: var(--muted); font-size: 15px; }
.step-num {
  display: inline-grid; place-items: center; width: 32px; height: 32px; border-radius: 50%;
  background: var(--accent-soft); color: var(--accent-strong); font-weight: 800;
}
.pill-link { text-decoration: none; font-size: 14px; padding: 6px 14px; color: var(--text); border: 1px solid var(--border); background: var(--surface); }
.pill-link:hover { border-color: var(--accent); color: var(--accent); }
.cta-band { display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.cta-band h2 { margin: 0 0 4px; font-size: 20px; }
.cta-band p { margin: 0; color: var(--muted); }
.cta-band .btn { text-decoration: none; }
.brand[aria-current="page"] { cursor: default; }