body {
  min-height: 100vh;
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(120deg, #74ebd5 0%, #ACB6E5 100%);
  display: flex;
  align-items: center;
  justify-content: center;
}

.main-wrapper {
  width: 100vw;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.card {
  background: rgba(255,255,255,0.85);
  box-shadow: 20px 20px 20px rgba(0, 0, 0, 0.15);
  border-radius: 18px;
  padding: clamp(28px, 6vw, 44px);
  max-width: 400px;
  width: 90vw;
  display: flex;
  flex-direction: column;
  gap: 20px;
  align-items: stretch;
  backdrop-filter: blur(8px);
  animation: fadeIn 1.5s cubic-bezier(.4,0,.2,1);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(30px);}
  to { opacity: 1; transform: translateY(0);}
}

h1 {
  font-size: clamp(1.7rem, 4vw, 2.4rem);
  font-weight: 700;
  color: #2d3a4a;
  margin-bottom: 4px;
  letter-spacing: 1px;
  text-align: center;
}

.subtitle {
  text-align: center;
  color: #5a6d8a;
  font-size: clamp(1rem, 2vw, 1.15rem);
  margin-bottom: 10px;
  opacity: 0.85;
}

.input-group {
  display: flex;
  gap: 10px;
}

input[type="text"] {
  flex: 1;
  padding: clamp(12px, 3vw, 16px);
  font-size: clamp(1rem, 2vw, 1.1rem);
  border-radius: 10px;
  color:white;
  border: 1px solid #bfc9d4;
  transition: border 0.2s, box-shadow 0.2s;
  outline: none;
  box-sizing: border-box;
  background: rgba(0, 0, 0, 0.95);
}

input[type="text"]:focus {
  border-color: #74ebd5;
  box-shadow: 0 0 8px #74ebd5aa;
}

button {
  padding: clamp(10px, 2vw, 14px);
  font-size: clamp(0.95rem, 2vw, 1.05rem);
  border-radius: 8px;
  border: none;
  background: linear-gradient(90deg, #74ebd5 0%, #ACB6E5 100%);
  color: #2d3a4a;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  box-shadow: 0 2px 8px rgba(44,62,80,0.07);
}

button:hover {
  background: linear-gradient(90deg, #ACB6E5 0%, #74ebd5 100%);
  transform: scale(1.04);
  box-shadow: 0 4px 16px rgba(44,62,80,0.12);
}

button:active {
  transform: scale(0.98);
}

button:focus {
  outline: 2px solid #74ebd5;
  outline-offset: 2px;
}

#clear-all {
  background: linear-gradient(90deg, #ff6a6a 0%, #ffb86c 100%);
  color: #fff;
  margin-top: 8px;
}

#clear-all:hover, #clear-all:focus {
  background: linear-gradient(90deg, #ffb86c 0%, #ff6a6a 100%);
}

ul#todo-list {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 1rem;
  color: #333;
}

ul#todo-list li {
  background: #f6f8fa;
  border-radius: 8px;
  margin-bottom: 8px;
  padding: 10px 14px;
  box-shadow: 0 1px 4px rgba(44,62,80,0.05);
  word-break: break-word;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background 0.2s;
  gap: 10px;
}

ul#todo-list li.completed {
  text-decoration: line-through;
  color: #aaa;
  background: #e0e0e0;
}

ul#todo-list li input[type="checkbox"] {
  accent-color: #74ebd5;
  width: 1.2em;
  height: 1.2em;
  margin-right: 8px;
  cursor: pointer;
}

ul#todo-list li button {
  background: none;
  color: #ff6a6a;
  font-size: 1.2em;
  border: none;
  cursor: pointer;
  box-shadow: none;
  padding: 0 6px;
  transition: color 0.2s;
}

ul#todo-list li button:hover {
  color: #ffb86c;
}

.completed {
  text-decoration: line-through;
  color:gray;
  opacity: 0.7;
}

@media (max-width: 600px) {
  .card {
    padding: 16px;
    border-radius: 8px;
    max-width: 100vw;
  }
  .main-wrapper {
    padding: 0;
  }
  .input-group {
    flex-direction: column;
    gap: 8px;
  }
  button, input[type="text"] {
    width: 100%;
  }
}