* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: #f4f5f7;
  color: #222;
  margin: 0;
  padding: 24px;
}

h1 {
  text-align: center;
  margin-bottom: 24px;
}

.signin {
  max-width: 320px;
  margin: 0 auto 24px;
  background: #fff;
  border-radius: 10px;
  padding: 16px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
  text-align: center;
}

.signin-form {
  display: flex;
  gap: 8px;
  margin-top: 12px;
}

.signin-form input {
  flex: 1;
  padding: 8px;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 0.95rem;
}

.signin-form button {
  padding: 8px 12px;
  border: none;
  border-radius: 6px;
  background: #4a7dff;
  color: #fff;
  cursor: pointer;
  font-size: 0.95rem;
}

.signin-form button:hover {
  background: #3a6ae0;
}

.signin-error {
  color: #c00;
  margin: 10px 0 0;
  font-size: 0.9rem;
}

.signout-btn {
  display: block;
  margin: 24px auto 0;
  padding: 8px 12px;
  border: 1px solid #ccc;
  border-radius: 6px;
  background: #fff;
  cursor: pointer;
  font-size: 0.9rem;
}

.signout-btn:hover {
  background: #f0f0f0;
}

.board {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
  max-width: 1000px;
  margin: 0 auto;
}

.list-section {
  background: #fff;
  border-radius: 10px;
  padding: 16px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
}

.list-section h2 {
  margin-top: 0;
  font-size: 1.2rem;
  border-bottom: 2px solid #eee;
  padding-bottom: 8px;
}

.add-form {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
}

.add-form input {
  flex: 1;
  padding: 8px;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 0.95rem;
}

.add-form button {
  padding: 8px 12px;
  border: none;
  border-radius: 6px;
  background: #4a7dff;
  color: #fff;
  cursor: pointer;
  font-size: 0.95rem;
}

.add-form button:hover {
  background: #3a6ae0;
}

.items {
  list-style: none;
  margin: 0;
  padding: 0;
}

.items li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 4px;
  border-bottom: 1px solid #f0f0f0;
}

.items li:last-child {
  border-bottom: none;
}

.items li span {
  flex: 1;
  word-break: break-word;
}

.items li.done span {
  text-decoration: line-through;
  color: #999;
}

.items li .delete-btn {
  border: none;
  background: transparent;
  color: #c00;
  font-size: 1.1rem;
  cursor: pointer;
  line-height: 1;
  padding: 2px 6px;
}

.items li .delete-btn:hover {
  color: #900;
}