body {
  font-family: Arial, sans-serif;
  background: #f5f7fa;
  margin: 0;
  padding: 0;
}

#app {
  max-width: 800px;
  margin-left: 20px;
  margin-right: auto;
  padding: 20px;
  text-align: left;
}

h1 {
  text-align: center;
}

input,
button {
  padding: 10px;
  margin: 5px;
  font-size: 16px;
}

button {
  background: #fc6d26;
  border: none;
  color: white;
  cursor: pointer;
  border-radius: 5px;
}

button:hover {
  background: #e3551a;
}

.chapter {
  background: white;
  margin-bottom: 15px;
  padding: 10px;
  border-radius: 6px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.lab {
  padding: 8px 0;
  border-bottom: 1px solid #ddd;
}

.lab:last-child {
  border-bottom: none;
}

.lab.done {
  background: #e7f7e7;
}

#progress-container {
  margin: 15px 0;
  background: #ddd;
  border-radius: 5px;
  height: 24px;
  overflow: hidden;
}

#progress-bar {
  background: #4caf50;
  color: white;
  text-align: center;
  height: 100%;
  line-height: 24px;
  white-space: nowrap;
}