:root {
  --bg: #0e1220; --panel: #181d33; --panel2: #1f2542; --line: #2c3358;
  --ink: #eef1fb; --muted: #99a0c2; --gold: #ffce4f; --accent: #6c7bff;
  --green: #22c55e; --red: #ef4444;
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}
.wrap { max-width: 980px; margin: 0 auto; padding: 0 20px; }
.row { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.head-right { display: flex; align-items: center; gap: 12px; }
header { background: linear-gradient(160deg, #1a2140, #0e1220); border-bottom: 1px solid var(--line); padding: 24px 0; }
header h1 { margin: 0 0 4px; font-size: 26px; }
.tag { margin: 0; color: var(--muted); }
.badge { display: inline-block; font-size: 12px; color: var(--muted);
  background: var(--panel2); border: 1px solid var(--line); border-radius: 999px; padding: 4px 12px; }

main { margin: 28px auto; }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 16px; padding: 20px; margin: 0 0 22px; }
.card.narrow { max-width: 460px; margin: 40px auto; }
h2 { font-size: 19px; margin: 0 0 12px; }
.muted { color: var(--muted); }
.small { font-size: 13px; }
.err { color: var(--red); font-size: 13px; }
.hint { background: rgba(108,123,255,0.12); border: 1px solid var(--line); border-radius: 10px;
  padding: 8px 12px; color: var(--ink); margin: 0 0 14px; }
.hint b { color: var(--gold); font-weight: 700; }

label { font-size: 13px; color: var(--muted); display: inline-block; }
label.block { display: block; margin: 0 0 12px; }
label.grow { flex: 1; }
input, select, textarea {
  width: 100%; background: var(--panel2); color: var(--ink);
  border: 1px solid var(--line); border-radius: 10px; padding: 10px; font: inherit; margin-top: 4px;
}
input.time { width: 110px; }
textarea { resize: vertical; }
.grid4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; }
.controls { display: flex; align-items: flex-end; gap: 12px; margin-top: 12px; flex-wrap: wrap; }
.check { display: flex; align-items: center; gap: 8px; margin-top: 12px; color: var(--ink); font-size: 14px; }
.check input { width: auto; margin: 0; }

button { background: var(--panel2); color: var(--ink); border: 1px solid var(--line);
  border-radius: 10px; padding: 10px 16px; font: inherit; cursor: pointer; white-space: nowrap; }
button:hover { border-color: var(--accent); }
button.primary { background: var(--accent); border-color: var(--accent); font-weight: 600; }
button.danger { background: #3a1d28; border-color: #7a3045; color: #ffd9e0; }
button.ghost { background: transparent; }
button:disabled { opacity: .5; cursor: default; }
.filebtn { background: var(--panel2); border: 1px solid var(--line); border-radius: 10px;
  padding: 10px 16px; cursor: pointer; color: var(--ink); font-size: 14px; margin-top: 0; }
.filebtn:hover { border-color: var(--accent); }

/* tabs */
.tabs { display: flex; gap: 8px; border-bottom: 1px solid var(--line); margin-bottom: 16px; flex-wrap: wrap; }
.tab { background: transparent; border: none; border-bottom: 2px solid transparent; border-radius: 0;
  padding: 8px 12px; color: var(--muted); }
.tab.active { color: var(--ink); border-bottom-color: var(--accent); }
.tab:hover { color: var(--ink); border-color: transparent; border-bottom-color: var(--line); }

/* record sub-tabs + whiteboard */
.subtabs { display: flex; gap: 8px; margin: 8px 0 14px; flex-wrap: wrap; }
.subtab { background: var(--panel2); border: 1px solid var(--line); border-radius: 999px;
  padding: 6px 14px; font-size: 13px; color: var(--muted); }
.subtab.active { color: var(--ink); border-color: var(--accent); }
.wb-toolbar { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin-bottom: 10px; }
.wb-tool { font-size: 13px; }
.wb-tool.active { border-color: var(--accent); color: var(--ink); }
.wb-ctl { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--muted); }
.wb-ctl input[type=color] { width: 36px; height: 30px; padding: 0; margin: 0; border-radius: 6px; }
.wb-ctl input[type=range] { width: 110px; margin: 0; }
.wb-stage { position: relative; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; background: #fff; }
#wb-canvas { display: block; width: 100%; aspect-ratio: 16 / 9; touch-action: none; cursor: crosshair; }
.wb-textinput { position: absolute; background: transparent; border: 1px dashed var(--accent);
  border-radius: 4px; padding: 1px 4px; font-weight: 700; outline: none; color: #111; min-width: 60px;
  font-family: -apple-system, BlinkMacSystemFont, sans-serif; }

/* preview */
.preview { margin-top: 16px; background: #000; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.preview iframe, .preview video { width: 100%; aspect-ratio: 16 / 9; display: block; border: 0; }

/* generate slide editor */
.slide { background: var(--panel2); border: 1px solid var(--line); border-radius: 12px; padding: 14px; margin: 0 0 12px; }
.slide .row { align-items: flex-start; }
.slide h4 { margin: 0 0 8px; font-size: 14px; color: var(--gold); }
.slide .remove { padding: 4px 10px; font-size: 12px; }

/* library */
.lib { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; margin-top: 14px; }
.lesson { background: var(--panel2); border: 1px solid var(--line); border-radius: 14px; padding: 14px; }
.lesson.published { border-color: var(--gold); box-shadow: 0 0 0 1px var(--gold) inset; }
.lesson .kind { font-size: 11px; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
.lesson h3 { margin: 4px 0 8px; font-size: 16px; }
.lesson .thumb { background: #000; border-radius: 10px; overflow: hidden; margin-bottom: 10px; }
.lesson .thumb iframe, .lesson .thumb video, .lesson .thumb img { width: 100%; aspect-ratio: 16/9; display: block; border: 0; object-fit: cover; }
.lesson .badges { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; margin: 2px 0; }
.lesson .star { color: var(--gold); font-weight: 700; font-size: 12px; }
.yt { font-size: 11px; border-radius: 999px; padding: 2px 8px; border: 1px solid var(--line); }
.yt-ok { color: #0f172a; background: #86efac; border-color: #86efac; font-weight: 600; }
.yt-none { color: var(--muted); }
.yt-pending { color: var(--gold); border-color: var(--gold); }
.yt-err { color: #ffd9e0; background: #3a1d28; border-color: #7a3045; }
.lesson .actions { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 10px; }
.lesson .actions button { padding: 6px 10px; font-size: 13px; }
.empty { color: var(--muted); padding: 24px 0; text-align: center; }