.field{
 display: flex;
}

.container {
  display: flex;
  flex-direction: row; /* 縦並びにする場合は column */
  gap: 16px;
  padding: 20px;
}

.panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: left;
}

iframe {
  width: 100%;
  height: 450px;
  border: 1px solid #ccc;
  margin-bottom: 10px;
}