body {
  font-family: Arial, sans-serif;
  background: #f4f7f9;
  margin: 0;
  padding: 20px;
  color: #333;
}

.container {
  max-width: 800px;
  margin: auto;
  background: #fff;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

h1, h2 {
  text-align: center;
  color: #2c3e50;
}

.input-group {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}

#todo-input {
  width: 70%;
  padding: 10px;
  font-size: 16px;
}

.input-group button {
  padding: 10px 20px;
  font-size: 16px;
  background: #3498db;
  color: white;
  border: none;
  cursor: pointer;
}

.input-group button:hover {
  background: #2980b9;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 30px;
}

table, th, td {
  border: 1px solid #ddd;
}

th, td {
  padding: 12px;
  text-align: center;
}

th {
  background-color: #3498db;
  color: white;
}

button.complete-btn {
  background: #2ecc71;
  color: white;
  border: none;
  padding: 6px 10px;
  cursor: pointer;
}

button.complete-btn:hover {
  background: #27ae60;
}