* {
  box-sizing: border-box;
}

body {
  font-family: "Segoe UI", sans-serif;
  background: #f1f2f6;
  display: flex;
  justify-content: center;
  padding-top: 40px;
  margin: 0;
}

.container {
  background: white;
  padding: 30px;
  width: 100%;
  max-width: 450px;
  border-radius: 10px;
  box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
}

h1 {
  text-align: center;
  margin-bottom: 20px;
}

.input-section {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}

#task-input {
  flex: 1;
  padding: 12px;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 16px;
}

#add-btn {
  padding: 12px;
  background: #3498db;
  color: white;
  font-size: 18px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
}

#add-btn:hover {
  background: #2980b9;
}

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

li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #f9f9f9;
  margin-bottom: 10px;
  padding: 10px 14px;
  border-radius: 6px;
  transition: 0.2s;
}

li.completed span {
  text-decoration: line-through;
  color: gray;
}

.task-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

button.delete-btn {
  background: #e74c3c;
  color: white;
  border: none;
  padding: 6px 10px;
  border-radius: 4px;
  cursor: pointer;
}

button.delete-btn:hover {
  background: #c0392b;
}

.footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 20px;
}

#clear-completed {
  padding: 6px 12px;
  background: #8e44ad;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

#clear-completed:hover {
  background: #6c3483;
}