body {
  margin: 0;
  font-family: sans-serif;
  background-color: #121212;
  color: #f0f0f0;
  display: flex;
  justify-content: center;
  padding: 2rem;
}

.container {
  width: 100%;
  max-width: 900px;
}

h1 {
  text-align: center;
  margin-bottom: 2rem;
}

.day {
  background-color: #1e1e1e;
  border: 1px solid #333;
  border-radius: 8px;
  margin-bottom: 1rem;
  padding: 1rem;
}

.day h2 {
  margin-top: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.task-list {
  list-style: none;
  padding: 0;
}

.task-list li {
  display: flex;
  justify-content: space-between;
  background: #2c2c2c;
  padding: 0.5rem;
  margin-bottom: 0.5rem;
  border-radius: 4px;
}

.task-list li span {
  flex: 1;
  cursor: pointer;
}

.task-list li span.done {
  text-decoration: line-through;
  color: #888;
}

button {
  background: #3498db;
  border: none;
  color: white;
  padding: 0.3rem 0.6rem;
  border-radius: 4px;
  cursor: pointer;
  margin-left: 0.3rem;
}

button:hover {
  background: #2980b9;
}

input[type="text"] {
  width: 80%;
  padding: 0.5rem;
  margin-right: 0.5rem;
  border: none;
  border-radius: 4px;
}