* { box-sizing: border-box; }
body { margin: 0; font-family: system-ui, -apple-system, "Segoe UI", Arial, "Noto Sans TC", sans-serif; line-height: 1.5; }

.topbar {
  position: sticky;
  top: 0;
  background: #fff;
  border-bottom: 1px solid #e5e7eb;
  padding: 16px;
}

.menu {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 8px 0 12px;
}

.tab {
  padding: 8px 12px;
  border: 1px solid #111827;
  background: #f9fafb;
  cursor: pointer;
}
.tab:focus { outline: 3px solid #93c5fd; outline-offset: 2px; }

.hint { margin: 0 0 12px; color: #374151; }
.row { display: flex; gap: 8px; align-items: center; margin: 8px 0; flex-wrap: wrap; }

.display {
  padding: 10px 12px;
  border: 1px dashed #9ca3af;
  min-height: 44px;
}

.content { padding: 16px; }
.card {
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  padding: 16px;
  margin: 16px 0;
  background: #fff;
}
.filler { margin-top: 18px; height: 600px; color: #6b7280; }
kbd { border: 1px solid #9ca3af; border-bottom-width: 2px; padding: 1px 6px; border-radius: 6px; background: #f3f4f6; }