:root {
  --bg: #f4f5f7;
  --card: #ffffff;
  --text: #1d1f24;
  --muted: #5d6470;
  --accent: #2f7d32;
  --border: #d9dde3;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171b;
    --card: #1f2228;
    --text: #e8eaee;
    --muted: #a3a9b4;
    --accent: #6cc070;
    --border: #353a43;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  padding: 16px;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.55 system-ui, -apple-system, "Segoe UI", "Hiragino Sans", "Yu Gothic UI", sans-serif;
}
header, main { max-width: 860px; margin: 0 auto; }
h1 { font-size: 1.5rem; margin: 0.2em 0; }
h1 .sub { font-size: 0.9rem; color: var(--muted); font-weight: normal; }
h2 { font-size: 1.05rem; margin: 0 0 0.6em; }
header p { color: var(--muted); margin-top: 0.2em; }
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 16px;
  margin: 12px 0;
}
.card.small { font-size: 0.9rem; color: var(--muted); }
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 10px 14px;
  align-items: end;
}
label { display: flex; flex-direction: column; gap: 4px; font-size: 0.9rem; color: var(--muted); }
input, select, button {
  font: inherit;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 8px;
  max-width: 100%;
}
button { cursor: pointer; }
button#build {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 10px 18px;
  font-weight: 600;
}
button:disabled { opacity: 0.5; cursor: default; }
.download {
  display: inline-block;
  margin-left: 12px;
  font-weight: 600;
  color: var(--accent);
}
progress { display: block; width: 100%; margin: 12px 0 6px; }
#log {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 8px;
  height: 220px;
  overflow: auto;
  white-space: pre-wrap;
  font-size: 0.82rem;
  margin: 0;
}
#videoList { padding-left: 1.2em; margin: 8px 0 0; }
#videoList input { width: 9em; }
.hint { color: var(--muted); font-size: 0.85rem; margin: 10px 0 0; }
code { font-size: 0.9em; }