.studio-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 1.25rem;
  align-items: start;
}
.studio-side, .studio-main, .studio-quiz {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
}
.studio-side { padding: .75rem; max-height: 70vh; overflow: auto; }
.studio-side button, .studio-filters select {
  width: 100%;
  text-align: left;
  border: 0;
  background: transparent;
  font: inherit;
  padding: .55rem .65rem;
  border-radius: 10px;
  cursor: pointer;
  color: var(--ink);
}
.studio-side button:hover, .studio-side button[aria-current="true"] {
  background: var(--teal-soft);
  color: var(--teal-dark);
}
.studio-side .meta { display: block; font-size: .78rem; }
.studio-main { padding: 1.25rem 1.4rem; min-height: 280px; }
.studio-main h2 { font-size: 1.45rem; letter-spacing: -.02em; margin-bottom: .35rem; }
.notes h1, .notes h2, .notes h3 { margin: 1.1rem 0 .4rem; letter-spacing: -.02em; }
.notes p, .notes li { color: var(--muted); margin-bottom: .55rem; }
.notes ul, .notes ol { margin: 0 0 .8rem 1.2rem; }
.notes img { border-radius: 12px; margin: .6rem 0; }
.notes pre {
  background: var(--bg); border-radius: 12px; padding: .8rem 1rem;
  overflow: auto; font-size: .88rem; margin-bottom: .8rem;
}
.studio-quiz { margin-top: 1rem; padding: 1.1rem 1.25rem; }
.q-card { border-top: 1px solid var(--line); padding: .9rem 0; }
.q-card:first-of-type { border-top: 0; }
.q-card strong { display: block; margin-bottom: .45rem; }
.q-card label { display: flex; gap: .5rem; align-items: flex-start; margin: .35rem 0; color: var(--ink); }
.q-result { font-size: .88rem; margin-top: .35rem; }
.q-result.ok { color: var(--teal-dark); }
.q-result.bad { color: #b91c1c; }
.studio-filters { display: flex; gap: .6rem; margin-bottom: 1rem; flex-wrap: wrap; }
.studio-filters select {
  width: auto;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: .55rem .9rem;
  background: #fff;
}
.discover-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.join-actions { display: flex; flex-wrap: wrap; gap: .6rem; margin-top: 1rem; align-items: center; }
.join-scan { margin-top: 1rem; }
.join-scan-frame { position: relative; }
.join-scan video {
  width: 100%; max-height: 280px; background: #0f172a; border-radius: 12px; object-fit: cover;
}
.join-scan video.is-front { transform: scaleX(-1); }
.join-scan-flip {
  position: absolute; top: 8px; right: 8px;
  width: 40px; height: 40px; border: 0; border-radius: 50%;
  background: rgba(0,0,0,.55); color: #fff; cursor: pointer; font-size: 12px; font-weight: 700;
}
.discover-grid a.card { display: block; }
@media (max-width: 900px) {
  .studio-layout, .discover-grid { grid-template-columns: 1fr; }
  .studio-side { max-height: none; }
}