.tab-container {
  width: 100%;
  position: relative;
}

.tab-buttons {
  display: flex;
  margin-bottom: 20px;
}

.tab-button {
  padding: 10px 20px;
  border: none;
  background: none;
  cursor: pointer;
  border-bottom: 2px solid transparent;
}

#readme-tab:checked ~ .tab-buttons label[for="readme-tab"],
#todo-tab:checked ~ .tab-buttons label[for="todo-tab"] {
  border-bottom: 2px solid #000;
}

.tab-content {
  display: none;
  width: 100%;
  height: 600px;
}

#readme-tab:checked ~ .tab-content.readme-content,
#todo-tab:checked ~ .tab-content:not(.readme-content) {
  display: block;
}

.tab-content iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.readme-content {
  height: 100%;
  overflow-y: auto;
}

.readme-content h1 {
  margin-top: 0;
}