* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

body {
  background: #f4f6f8;
  color: #1a1a1a;
  min-height: 100vh;
}

.hidden {
  display: none !important;
}

/* Auth page */
.auth-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 20px;
}

.auth-card {
  background: white;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.08);
  width: 100%;
  max-width: 380px;
}

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

.tabs {
  display: flex;
  margin-bottom: 20px;
  border-bottom: 1px solid #e0e0e0;
}

.tab-btn {
  flex: 1;
  padding: 10px;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 15px;
  color: #888;
  border-bottom: 2px solid transparent;
}

.tab-btn.active {
  color: #2563eb;
  border-bottom-color: #2563eb;
  font-weight: 600;
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

input {
  padding: 12px;
  border: 1px solid #d1d5db;
  border-radius: 8px;
  font-size: 14px;
}

input:focus {
  outline: none;
  border-color: #2563eb;
}

button {
  padding: 12px;
  background: #2563eb;
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 15px;
  cursor: pointer;
  font-weight: 600;
}

button:hover {
  background: #1d4ed8;
}

.error {
  color: #dc2626;
  margin-top: 12px;
  font-size: 14px;
  text-align: center;
}

/* Dashboard */
.dashboard-container {
  max-width: 600px;
  margin: 0 auto;
  padding: 30px 20px;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

header div {
  display: flex;
  align-items: center;
  gap: 12px;
}

#userEmail {
  color: #666;
  font-size: 14px;
}

#logoutBtn {
  background: #ef4444;
  padding: 8px 14px;
  font-size: 13px;
}

#logoutBtn:hover {
  background: #dc2626;
}

.add-todo-form {
  display: flex;
  gap: 10px;
  margin-bottom: 24px;
}

.add-todo-form input {
  flex: 1;
}

.add-todo-form button {
  padding: 12px 20px;
}

.todo-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.todo-item {
  background: white;
  padding: 14px 16px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  gap: 12px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.todo-item.completed .todo-title {
  text-decoration: line-through;
  color: #999;
}

.todo-title {
  flex: 1;
  font-size: 15px;
}

.todo-item button {
  padding: 6px 10px;
  font-size: 12px;
  background: #ef4444;
}

.todo-item button:hover {
  background: #dc2626;
}

.empty-msg {
  text-align: center;
  color: #999;
  margin-top: 30px;
}