:root {
  color-scheme: dark;
  --bg: #090b10;
  --card: rgba(20, 25, 36, 0.86);
  --card-border: rgba(255, 255, 255, 0.10);
  --text: #eef4ff;
  --muted: #9ba9c0;
  --accent: #78f0c6;
  --accent-strong: #31d59d;
  --danger: #ff7a90;
  --ready: #8fb7ff;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.36);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 20% 10%, rgba(49, 213, 157, 0.20), transparent 30%),
    radial-gradient(circle at 80% 20%, rgba(143, 183, 255, 0.18), transparent 28%),
    var(--bg);
  color: var(--text);
}

.shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 28px;
}

.hero-card {
  width: min(940px, 100%);
  padding: clamp(24px, 5vw, 56px);
  border: 1px solid var(--card-border);
  border-radius: 32px;
  background: linear-gradient(145deg, rgba(23, 29, 42, 0.96), var(--card));
  box-shadow: var(--shadow);
}

.hero-card.compact { width: min(520px, 100%); }
.eyebrow { color: var(--accent); text-transform: uppercase; letter-spacing: .16em; font-weight: 700; font-size: .78rem; }
h1 { font-size: clamp(2.1rem, 6vw, 4.8rem); line-height: .96; margin: 0 0 18px; max-width: 860px; }
h2 { font-size: clamp(1.6rem, 4vw, 2.4rem); margin: 12px 0; }
.lead { color: var(--muted); font-size: clamp(1.05rem, 2vw, 1.3rem); line-height: 1.55; max-width: 760px; }
.lead.small { font-size: 1rem; }
.hint { color: var(--muted); font-size: .95rem; }

.panel { margin-top: 32px; }
.panel[hidden] { display: none; }
.primary-button, .secondary-button {
  border: 0;
  border-radius: 999px;
  padding: 15px 22px;
  font-weight: 800;
  font-size: 1rem;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  min-height: 52px;
}
.primary-button { background: var(--accent); color: #06100d; box-shadow: 0 10px 32px rgba(49, 213, 157, .25); }
.primary-button:disabled { opacity: .45; cursor: not-allowed; }
.secondary-button { color: var(--text); background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.12); }

.session-grid {
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 32px;
  align-items: center;
}
.qr-frame {
  background: #fff;
  border-radius: 28px;
  padding: 18px;
  display: grid;
  place-items: center;
}
.qr-frame img, .qr-frame svg { width: 100%; height: auto; display: block; }
.session-copy label { color: var(--muted); display: block; margin-bottom: 8px; }
.copy-row { display: flex; gap: 10px; }
.copy-row input {
  width: 100%;
  min-width: 0;
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 16px;
  padding: 13px 14px;
  color: var(--text);
  background: rgba(255,255,255,.06);
}
.timer { color: var(--muted); }
.status-pill {
  display: inline-flex;
  border-radius: 999px;
  padding: 8px 12px;
  font-weight: 800;
  font-size: .85rem;
  background: rgba(255,255,255,.08);
  color: var(--muted);
}
.status-pill.waiting { color: var(--accent); }
.status-pill.ready { color: var(--ready); }
.status-pill.danger { color: var(--danger); }

.upload-form { display: grid; gap: 18px; margin-top: 28px; }
.drop-zone {
  min-height: 220px;
  border: 2px dashed rgba(120,240,198,.46);
  border-radius: 28px;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 28px;
  cursor: pointer;
  background: rgba(120,240,198,.06);
}
.drop-zone span, .drop-zone strong { display: block; }
.drop-icon { font-size: 3rem; color: var(--accent); }
#file-input { position: absolute; inline-size: 1px; block-size: 1px; opacity: 0; pointer-events: none; }
.upload-status {
  margin-top: 18px;
  border-radius: 18px;
  padding: 16px;
  background: rgba(255,255,255,.07);
  color: var(--muted);
}

@media (max-width: 760px) {
  .shell { padding: 16px; align-items: start; }
  .hero-card { border-radius: 24px; padding: 24px; margin-top: 18px; }
  .session-grid { grid-template-columns: 1fr; }
  .copy-row { flex-direction: column; }
  .primary-button, .secondary-button { width: 100%; }
}