body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  margin: 0;
  padding: 0;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.app {
  background: white;
  width: 90%;
  max-width: 500px;
  padding: 2rem;
  border-radius: 16px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

h1 {
  text-align: center;
  color: #333;
  margin-bottom: 1.5rem;
}

#task-form {
  display: flex;
  gap: 10px;
  margin-bottom: 1.5rem;
}

#task-input {
  flex: 1;
  padding: 12px 15px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 1rem;
  transition: border 0.3s;
}

#task-input:focus {
  outline: none;
  border-color: #4CAF50;
}

button[type="submit"] {
  background-color: #4CAF50;
  color: white;
  border: none;
  padding: 12px 20px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: bold;
  transition: background 0.3s;
}

button[type="submit"]:hover {
  background-color: #45a049;
}

#task-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

#task-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #f9f9f9;
  margin-bottom: 10px;
  padding: 12px 15px;
  border-radius: 8px;
  border-left: 5px solid #4CAF50;
}

.task-text {
  flex: 1;
  margin: 0 15px;
}

.completed {
  text-decoration: line-through;
  color: #888;
}

.btn-complete,
.btn-delete {
  border: none;
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.2s;
}

.btn-complete {
  background-color: #2196F3;
  color: white;
}

.btn-complete:hover {
  background-color: #0b7dda;
}

.btn-delete {
  background-color: #ff5252;
  color: white;
}

.btn-delete:hover {
  background-color: #ff0000;
}