/* HuaFlow webapp — shared brand-aligned styles. */
:root {
  --black:#09090C; --slate:#0F172A; --card:#111116; --lift:#17171E;
  --border:#1E1E28; --border2:#28283A;
  --dmid:#72727E; --dsoft:#42424E; --dim:#64748B; --dim-bone:#94A3B8;
  --white:#F0F0F8; --bone:#F5F1E8;
  --v:#7B5CF0; --vl:#9D7FF5; --vd:#5B3DD0; --lavender:#A78BFA;
  --vg:rgba(123,92,240,.09); --vglow:rgba(123,92,240,.22);
  --green:#10B981; --amber:#F59E0B; --red:#F43F5E;
  --serif:'Fraunces',Georgia,serif;
  --sans:'Geist','Helvetica Neue',sans-serif;
  --mono:'Geist Mono',Menlo,monospace;
}
*,*::before,*::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { min-height: 100%; }
body {
  font-family: var(--sans);
  background: var(--black);
  color: var(--white);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  background-image:
    radial-gradient(ellipse at 20% 80%, rgba(30,27,75,.55) 0%, transparent 55%),
    radial-gradient(ellipse at 80% 20%, rgba(123,92,240,.10) 0%, transparent 50%);
  min-height: 100vh;
}
a { color: var(--vl); text-decoration: none; }
a:hover { color: var(--lavender); }

/* ─── Top bar ─── */
.topbar {
  position: sticky; top: 0; z-index: 50;
  background: rgba(9,9,12,0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  padding: 16px 28px;
  display: flex; justify-content: space-between; align-items: center;
}
.topbar .brand {
  font-family: var(--serif);
  font-size: 22px;
  letter-spacing: 0.2px;
}
.topbar .brand em { color: var(--vl); font-style: italic; }
.topbar nav { display: flex; gap: 18px; align-items: center; }
.topbar nav a, .topbar nav button {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--dim-bone);
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px 0;
  transition: color .12s;
}
.topbar nav a:hover, .topbar nav button:hover { color: var(--white); }

/* ─── Containers ─── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 40px 24px 80px 24px;
}
.container.narrow { max-width: 540px; }
h1 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 38px;
  letter-spacing: 0.2px;
  margin-bottom: 8px;
}
h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 22px;
  margin: 32px 0 12px 0;
}
.subtitle {
  font-family: var(--serif);
  font-style: italic;
  color: var(--lavender);
  font-size: 17px;
  margin-bottom: 28px;
}
.kicker {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 1.4px;
  text-transform: uppercase;
  color: var(--dim-bone);
}

/* ─── Forms ─── */
.field { margin-bottom: 18px; }
.field label {
  display: block;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--dim-bone);
  margin-bottom: 8px;
}
.field input {
  width: 100%;
  padding: 12px 14px;
  background: var(--card);
  border: 1px solid var(--border2);
  border-radius: 6px;
  color: var(--white);
  font-family: var(--sans);
  font-size: 15px;
  transition: border-color .12s, box-shadow .12s;
}
.field input:focus {
  outline: none;
  border-color: var(--v);
  box-shadow: 0 0 0 3px rgba(123,92,240,.15);
}
.btn {
  display: inline-block;
  padding: 12px 22px;
  background: var(--v);
  color: white;
  border: none;
  border-radius: 6px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 1.4px;
  text-transform: uppercase;
  cursor: pointer;
  transition: background .12s, transform .08s;
  text-align: center;
}
.btn:hover { background: var(--vd); color: white; }
.btn:active { transform: scale(0.98); }
.btn.full { width: 100%; }
.btn.secondary {
  background: transparent;
  border: 1px solid var(--border2);
  color: var(--white);
}
.btn.secondary:hover {
  background: rgba(255,255,255,.04);
  border-color: var(--lavender);
  color: var(--white);
}
.btn.ghost {
  background: transparent;
  color: var(--dim-bone);
  border: 1px solid var(--border);
}
.btn.ghost:hover { color: var(--white); border-color: var(--lavender); }

.alert {
  padding: 12px 14px;
  border-radius: 6px;
  font-size: 13px;
  margin-bottom: 16px;
  background: rgba(244,63,94,.10);
  border: 1px solid rgba(244,63,94,.35);
  color: var(--red);
}
.alert.ok {
  background: rgba(16,185,129,.10);
  border-color: rgba(16,185,129,.35);
  color: var(--green);
}

/* ─── Library tile grid ─── */
.tile-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 18px;
  margin-top: 24px;
}
.tile {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px 22px 18px 22px;
  display: flex; flex-direction: column;
  min-height: 220px;
  position: relative;
  transition: border-color .15s, transform .15s;
}
.tile:hover { border-color: var(--lavender); transform: translateY(-2px); }
.tile.locked { opacity: 0.62; }
.tile .audience-tag {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1.4px;
  text-transform: uppercase;
  color: var(--dim);
  margin-bottom: 10px;
}
.tile .level-tag {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1.4px;
  color: var(--vl);
  margin-bottom: 14px;
}
.tile h3 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 22px;
  line-height: 1.25;
  flex: 1;
  margin-bottom: 16px;
}
.tile .footer {
  display: flex; justify-content: space-between; align-items: center;
  margin-top: 8px;
}
.tile .price {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--white);
}
.tile .badge {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1px;
  text-transform: uppercase;
  padding: 4px 8px;
  border-radius: 4px;
  background: rgba(16,185,129,.12);
  color: var(--green);
  border: 1px solid rgba(16,185,129,.35);
}
.tile .lock {
  position: absolute; top: 18px; right: 18px;
  font-family: var(--mono); font-size: 16px; color: var(--dim);
}
.tile a.cta {
  display: block;
  text-align: center;
  padding: 10px 14px;
  border: 1px solid var(--border2);
  border-radius: 6px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--white);
  transition: border-color .12s, background .12s;
}
.tile a.cta:hover { border-color: var(--lavender); background: rgba(167,139,250,.08); }
.tile a.cta.primary { background: var(--v); border-color: var(--v); }
.tile a.cta.primary:hover { background: var(--vd); border-color: var(--vd); }

/* ─── Audience filter chips ─── */
.chips {
  display: flex; gap: 8px; flex-wrap: wrap;
  margin: 16px 0 8px 0;
}
.chip {
  padding: 6px 12px;
  border: 1px solid var(--border2);
  border-radius: 999px;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--dim-bone);
  cursor: pointer;
  transition: all .12s;
}
.chip:hover { color: var(--white); border-color: var(--lavender); }
.chip.active { background: var(--v); color: white; border-color: var(--v); }

/* ─── Book reader page ─── */
.reader-grid {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 28px;
}
@media (max-width: 760px) { .reader-grid { grid-template-columns: 1fr; } }
.asset-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 22px;
  margin-bottom: 14px;
}
.asset-card h3 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 19px;
  margin-bottom: 6px;
}
.asset-card p {
  font-size: 13px;
  color: var(--dim-bone);
  margin-bottom: 14px;
}

/* ─── Footer ─── */
footer {
  border-top: 1px solid var(--border);
  padding: 24px 28px;
  display: flex; justify-content: space-between; align-items: center;
  font-family: var(--mono);
  font-size: 10px;
  color: var(--dim);
  letter-spacing: .8px;
  margin-top: 60px;
}
footer .slogan { font-family: var(--serif); font-style: italic; color: var(--lavender); font-size: 11px; }

@media (max-width: 600px) {
  .topbar { padding: 12px 18px; }
  .topbar nav { gap: 12px; }
  .topbar nav a, .topbar nav button { font-size: 10px; letter-spacing: .8px; }
  .container { padding: 28px