:root {
  color-scheme: light;
  --ink: #1c1c1c;
  --muted: #6b6b6b;
  --border: #d8d8d8;
  --accent: #ffe86d;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 2rem 1rem;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--ink);
  background: #fafafa;
}

main {
  max-width: 640px;
  margin: 0 auto;
}

h1 {
  margin-bottom: 0.25rem;
}

.subtitle {
  color: var(--muted);
  margin-top: 0;
}

#drop-zone {
  border: 2px dashed var(--border);
  border-radius: 12px;
  padding: 2.5rem 1rem;
  text-align: center;
  cursor: pointer;
  color: var(--muted);
  transition: border-color 0.15s, background 0.15s;
}

#drop-zone:hover,
#drop-zone:focus,
#drop-zone.dragover {
  border-color: var(--accent);
  background: #fffbea;
}

#status {
  min-height: 1.5rem;
  color: var(--muted);
}

#status.error {
  color: #b00020;
}

#filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  margin: 0 0 1rem;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
}

#filters legend {
  padding: 0 0.4rem;
  color: var(--muted);
  font-size: 0.85rem;
}

#filters label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.9rem;
  cursor: pointer;
}

#chapters-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

#chapters-list li {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.4rem 0;
}

#chapters-list li.subchapter {
  margin-left: 1.75rem;
}

#chapters-list input[type="text"] {
  flex: 1;
  padding: 0.4rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 1rem;
}

#chapters-list li.subchapter input[type="text"] {
  font-size: 0.9rem;
}

#generate-btn {
  margin-top: 1.5rem;
  padding: 0.6rem 1.5rem;
  border: none;
  border-radius: 8px;
  background: var(--ink);
  color: white;
  font-size: 1rem;
  cursor: pointer;
}

#generate-btn:hover {
  opacity: 0.9;
}