* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background: #f3f4f6;
  color: #111827;
}

.app {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 30px 20px;
}

.todo-box {
  width: 100%;
  max-width: 600px;
  background: #ffffff;
  padding: 30px;
  border-radius: 18px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
}

h1 {
  text-align: center;
  margin-bottom: 10px;
  font-size: 2rem;
}

.subtitle {
  text-align: center;
  color: #6b7280;
  margin-bottom: 24px;
}

.input-group {
  display: flex;
  gap: 12px;
  margin-bottom: 24px;
}

.input-group input {
  flex: 1;
  padding: 14px;
  border: 1px solid #d1d5db;
  border-radius: 10px;
  font-size: 1rem;
}

.input-group button {
  padding: 14px 18px;
  border: none;
  background: #2563eb;
  color: white;
  border-radius: 10px;
  font-weight: bold;
  cursor: pointer;
}

.input-group button:hover {
  background: #1d4ed8;
}

#taskList {
  list-style: none;
}

.task-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  background: #f9fafb;
  border: 1px solid #e5e7eb;
  padding: 14px 16px;
  border-radius: 12px;
  margin-bottom: 12px;
}

.task-text {
  flex: 1;
  text-align: left;
}

.completed {
  text-decoration: line-through;
  color: #9ca3af;
}

.task-actions {
  display: flex;
  gap: 8px;
}

.complete-btn,
.delete-btn {
  border: none;
  padding: 10px 12px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: bold;
}

.complete-btn {
  background: #dbeafe;
  color: #1d4ed8;
}

.delete-btn {
  background: #fee2e2;
  color: #dc2626;
}

.complete-btn:hover {
  background: #bfdbfe;
}

.delete-btn:hover {
  background: #fecaca;
}

@media (max-width: 640px) {
  .input-group {
    flex-direction: column;
  }

  .input-group button {
    width: 100%;
  }

  .task-item {
    flex-direction: column;
    align-items: stretch;
  }

  .task-actions {
    justify-content: flex-end;
  }
}