* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Segoe UI', sans-serif;
  background: linear-gradient(to right, #e3f2fd, #90caf9);
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
  padding: 20px;
  transition: background 0.5s ease-in-out;
}

.container {
  background: white;
  padding: 25px 20px;
  border-radius: 15px;
  box-shadow: 0 0 15px rgba(0,0,0,0.15);
  width: 100%;
  max-width: 400px;
  transition: transform 0.3s ease;
}

.container:hover {
  transform: scale(1.01);
}

h1 {
  text-align: center;
  color: #1976d2;
  margin-bottom: 20px;
  font-size: 1.8rem;
}

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

input[type="text"] {
  flex: 1;
  padding: 10px;
  font-size: 1rem;
  border: 1px solid #bbb;
  border-radius: 8px;
  outline: none;
  min-width: 0;
  transition: border 0.3s;
}

input[type="text"]:focus {
  border-color: #1976d2;
}

button {
  background: #1976d2;
  color: white;
  border: none;
  padding: 10px 14px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.3s ease;
  font-size: 1rem;
  white-space: nowrap;
}

button:hover {
  background: #0d47a1;
}

ul {
  padding-left: 20px;
}

li {
  padding: 10px;
  background: #e3f2fd;
  margin-bottom: 10px;
  border-radius: 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  word-break: break-word;
  transition: all 0.3s ease;
  list-style-type: disc;
  color: black;
}

li::marker {
  color: black;
}

li.completed {
  text-decoration: line-through;
  opacity: 0.6;
}

li button {
  background: transparent;
  border: none;
  color: #f44336;
  font-size: 1.2rem;
  font-weight: bold;
  cursor: pointer;
  padding-left: 10px;
}

.download-btn {
  margin-top: 15px;
  width: 100%;
}

/* Responsive Design */
@media screen and (max-width: 480px) {
  .container {
    padding: 20px 15px;
  }

  .input-section {
    flex-direction: column;
    gap: 10px;
  }

  button {
    width: 100%;
    padding: 12px;
  }

  h1 {
    font-size: 1.5rem;
  }
}