* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f5f5f5;
  color: #151515;
}
.app {
  width: min(720px, 100%);
  margin: 0 auto;
  padding: 24px;
}
.card {
  background: #fff;
  border: 1px solid #ddd;
  border-radius: 18px;
  padding: 24px;
  box-shadow: 0 8px 30px rgba(0,0,0,.06);
}
h1 { margin: 0 0 18px; }
.add-form {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
}
input, button {
  font: inherit;
  border-radius: 12px;
}
input {
  border: 1px solid #bbb;
  padding: 12px 14px;
}
button {
  border: 0;
  padding: 12px 16px;
  background: #111;
  color: #fff;
  cursor: pointer;
}
button:hover { opacity: .9; }
.secondary {
  width: 100%;
  margin-top: 16px;
  background: #eee;
  color: #111;
}
.status {
  min-height: 22px;
  color: #555;
}
.list {
  list-style: none;
  padding: 0;
  margin: 16px 0 0;
  display: grid;
  gap: 8px;
}
.item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 10px;
  padding: 12px;
  border: 1px solid #e1e1e1;
  border-radius: 14px;
  background: #fafafa;
}
.item input[type="checkbox"] {
  width: 22px;
  height: 22px;
}
.item.done .name {
  text-decoration: none;
  color: inherit;
  font-weight: 700;
}
.delete {
  background: transparent;
  color: #b00020;
  padding: 6px 8px;
}
.empty {
  color: #666;
  text-align: center;
  padding: 22px;
}
@media (max-width: 520px) {
  .app { padding: 12px; }
  .card { padding: 16px; }
  .add-form { grid-template-columns: 1fr; }
}