/* Reset & Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Light Mode Colors */
  --primary-color: #007bff;
  --secondary-color: #5c5cfc;
  --danger-color: #ff6b6b;
  --success-color: #28a745;
  --warning-color: #ffc107;
  --dark-color: #1e1e2f;
  --light-color: #ffffff;
  --muted-color: #f4f4f4;
  --text-primary: #333333;
  --text-secondary: #666666;
  --text-muted: #999999;
  --border-color: #e0e0e0;
  --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.15);
  --gradient-primary: linear-gradient(135deg, #007bff, #5c5cfc);
  --gradient-success: linear-gradient(135deg, #28a745, #20c997);
  --gradient-danger: linear-gradient(135deg, #ff6b6b, #ff5252);
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-gradient: linear-gradient(135deg, #f8f9fa 0%, #e3f2fd 100%);
}

[data-theme="dark"] {
  /* Dark Mode Colors */
  --primary-color: #4dabf7;
  --secondary-color: #7c3aed;
  --bg-primary: #1e1e2f;
  --bg-secondary: #2d2d44;
  --bg-gradient: linear-gradient(135deg, #1e1e2f 0%, #2d2d44 100%);
  --text-primary: #ffffff;
  --text-secondary: #b8b8b8;
  --text-muted: #888888;
  --border-color: #404040;
  --muted-color: #2d2d44;
  --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.4);
}

body {
  font-family: "Poppins", sans-serif;
  background: var(--bg-gradient);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  transition: all 0.3s ease;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

/* Theme Toggle */
.theme-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  width: 50px;
  height: 50px;
  border: 2px solid var(--border-color);
  background: var(--bg-primary);
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  color: var(--text-primary);
  transition: all 0.3s ease;
  z-index: 1000;
  box-shadow: var(--shadow);
}

.theme-toggle:hover {
  transform: scale(1.1);
  box-shadow: var(--shadow-hover);
}

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

.auth-container {
  background: var(--bg-primary);
  padding: 40px;
  border-radius: 20px;
  box-shadow: var(--shadow-hover);
  width: 100%;
  max-width: 400px;
  animation: slideInUp 0.5s ease;
}

.auth-header {
  text-align: center;
  margin-bottom: 30px;
}

.auth-title {
  font-size: 2.5rem;
  font-weight: 700;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 10px;
}

.auth-subtitle {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.auth-tabs {
  display: flex;
  margin-bottom: 30px;
  background: var(--muted-color);
  border-radius: 10px;
  padding: 4px;
}

.auth-tab {
  flex: 1;
  padding: 12px;
  border: none;
  background: transparent;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all 0.3s ease;
}

.auth-tab.active {
  background: var(--bg-primary);
  color: var(--text-primary);
  box-shadow: var(--shadow);
}

.auth-form {
  display: none;
}

.auth-form.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

.input-group {
  position: relative;
  margin-bottom: 20px;
}

.input-icon {
  position: absolute;
  left: 15px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 16px;
}

.input-group input {
  width: 100%;
  padding: 15px 15px 15px 45px;
  border: 2px solid var(--border-color);
  border-radius: 10px;
  font-size: 16px;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: all 0.3s ease;
}

.input-group input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.auth-btn {
  width: 100%;
  padding: 15px;
  border: none;
  border-radius: 10px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.login-btn {
  background: var(--gradient-primary);
  color: white;
}

.register-btn {
  background: var(--gradient-success);
  color: white;
}

.auth-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}

.auth-btn:disabled {
  opacity: 0.7;
  cursor: not-allowed;
  transform: none;
}

.loading-spinner {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.success-message {
  text-align: center;
  animation: bounceIn 0.5s ease;
}

.success-icon {
  font-size: 4rem;
  color: var(--success-color);
  margin-bottom: 20px;
  animation: bounce 1s infinite;
}

/* Dashboard Section */
.dashboard-section {
  min-height: 100vh;
  padding-top: 80px;
}

.dashboard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
  flex-wrap: wrap;
  gap: 20px;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 15px;
}

.user-avatar {
  width: 60px;
  height: 60px;
  background: var(--gradient-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 24px;
}

.user-details h1 {
  font-size: 1.8rem;
  font-weight: 600;
  margin-bottom: 5px;
}

.user-details p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.logout-btn {
  padding: 12px 20px;
  border: 2px solid var(--border-color);
  background: var(--bg-primary);
  color: var(--text-primary);
  border-radius: 10px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logout-btn:hover {
  border-color: var(--danger-color);
  color: var(--danger-color);
  background: rgba(255, 107, 107, 0.1);
}

/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin-bottom: 30px;
}

.stat-card {
  background: var(--bg-primary);
  padding: 25px;
  border-radius: 15px;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 15px;
  transition: all 0.3s ease;
}

.stat-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
}

.stat-icon {
  width: 50px;
  height: 50px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: white;
}

.stat-icon.total {
  background: var(--gradient-primary);
}

.stat-icon.completed {
  background: var(--gradient-success);
}

.stat-icon.remaining {
  background: var(--gradient-danger);
}

.stat-info h3 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 5px;
}

.stat-info p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Progress Card */
.progress-card {
  background: var(--bg-primary);
  padding: 25px;
  border-radius: 15px;
  box-shadow: var(--shadow);
  margin-bottom: 30px;
}

.progress-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 15px;
}

.progress-header h3 {
  font-size: 1.2rem;
  font-weight: 600;
}

.progress-badge {
  background: var(--muted-color);
  padding: 5px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.progress-bar {
  width: 100%;
  height: 12px;
  background: var(--muted-color);
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 10px;
}

.progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 6px;
  transition: width 0.5s ease;
  width: 0%;
}

.progress-text {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Add Todo Card */
.add-todo-card {
  background: var(--bg-primary);
  padding: 25px;
  border-radius: 15px;
  box-shadow: var(--shadow);
  margin-bottom: 30px;
}

.add-todo-form {
  display: flex;
  gap: 15px;
}

#newTodoInput {
  flex: 1;
  padding: 15px 20px;
  border: 2px solid var(--border-color);
  border-radius: 10px;
  font-size: 16px;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: all 0.3s ease;
}

#newTodoInput:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.add-btn {
  width: 50px;
  height: 50px;
  border: none;
  background: var(--gradient-primary);
  color: white;
  border-radius: 10px;
  cursor: pointer;
  font-size: 18px;
  transition: all 0.3s ease;
}

.add-btn:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-hover);
}

/* Filter Tabs */
.filter-tabs {
  display: flex;
  gap: 10px;
  margin-bottom: 30px;
  flex-wrap: wrap;
}

.filter-tab {
  padding: 12px 20px;
  border: 2px solid var(--border-color);
  background: var(--bg-primary);
  color: var(--text-secondary);
  border-radius: 10px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
}

.filter-tab.active {
  background: var(--gradient-primary);
  color: white;
  border-color: transparent;
}

.filter-tab:hover:not(.active) {
  border-color: var(--primary-color);
  color: var(--primary-color);
}

/* Todo List */
.todo-list {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.todo-item {
  background: var(--bg-primary);
  padding: 20px;
  border-radius: 15px;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 15px;
  transition: all 0.3s ease;
  animation: slideInLeft 0.3s ease;
}

.todo-item:hover {
  transform: translateX(5px);
  box-shadow: var(--shadow-hover);
}

.todo-item.completed {
  opacity: 0.7;
}

.todo-item.deleting {
  animation: slideOutRight 0.3s ease forwards;
}

.todo-checkbox {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  flex-shrink: 0;
}

.todo-checkbox.checked {
  background: var(--success-color);
  border-color: var(--success-color);
  color: white;
}

.todo-content {
  flex: 1;
  min-width: 0;
}

.todo-text {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: 5px;
  word-wrap: break-word;
  transition: all 0.3s ease;
}

.todo-text.completed {
  text-decoration: line-through;
  color: var(--text-muted);
}

.todo-date {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.priority-badge {
  padding: 5px 10px;
  border-radius: 15px;
  font-size: 0.7rem;
  font-weight: 600;
  color: white;
  flex-shrink: 0;
}

.priority-badge.high {
  background: var(--danger-color);
}

.priority-badge.medium {
  background: var(--warning-color);
}

.priority-badge.low {
  background: var(--success-color);
}

.todo-actions {
  display: flex;
  gap: 10px;
  flex-shrink: 0;
}

.todo-btn {
  width: 35px;
  height: 35px;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  transition: all 0.3s ease;
}

.priority-btn-todo {
  background: var(--muted-color);
  color: var(--text-secondary);
}

.priority-btn-todo:hover {
  background: var(--primary-color);
  color: white;
}

.delete-btn {
  background: rgba(255, 107, 107, 0.1);
  color: var(--danger-color);
}

.delete-btn:hover {
  background: var(--danger-color);
  color: white;
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  background: var(--bg-primary);
  border-radius: 15px;
  box-shadow: var(--shadow);
}

.empty-icon {
  font-size: 4rem;
  margin-bottom: 20px;
}

.empty-state h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.empty-state p {
  color: var(--text-secondary);
}

/* Modal */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  animation: fadeIn 0.3s ease;
}

.modal-content {
  background: var(--bg-primary);
  padding: 30px;
  border-radius: 15px;
  box-shadow: var(--shadow-hover);
  width: 90%;
  max-width: 400px;
  animation: scaleIn 0.3s ease;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.modal-header h3 {
  font-size: 1.3rem;
  font-weight: 600;
}

.modal-close {
  width: 30px;
  height: 30px;
  border: none;
  background: var(--muted-color);
  border-radius: 50%;
  cursor: pointer;
  font-size: 18px;
  color: var(--text-secondary);
  transition: all 0.3s ease;
}

.modal-close:hover {
  background: var(--danger-color);
  color: white;
}

.priority-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.priority-btn {
  padding: 15px 20px;
  border: 2px solid var(--border-color);
  background: var(--bg-primary);
  color: var(--text-primary);
  border-radius: 10px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 10px;
}

.priority-btn.high:hover {
  border-color: var(--danger-color);
  background: rgba(255, 107, 107, 0.1);
  color: var(--danger-color);
}

.priority-btn.medium:hover {
  border-color: var(--warning-color);
  background: rgba(255, 193, 7, 0.1);
  color: var(--warning-color);
}

.priority-btn.low:hover {
  border-color: var(--success-color);
  background: rgba(40, 167, 69, 0.1);
  color: var(--success-color);
}

/* Animations */
@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideOutRight {
  to {
    opacity: 0;
    transform: translateX(100%);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes bounceIn {
  0% {
    opacity: 0;
    transform: scale(0.3);
  }
  50% {
    opacity: 1;
    transform: scale(1.05);
  }
  70% {
    transform: scale(0.9);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.8);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes bounce {
  0%,
  20%,
  53%,
  80%,
  100% {
    transform: translate3d(0, 0, 0);
  }
  40%,
  43% {
    transform: translate3d(0, -30px, 0);
  }
  70% {
    transform: translate3d(0, -15px, 0);
  }
  90% {
    transform: translate3d(0, -4px, 0);
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 15px;
  }

  .dashboard-section {
    padding-top: 60px;
  }

  .auth-container {
    padding: 30px 20px;
  }

  .auth-title {
    font-size: 2rem;
  }

  .dashboard-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 15px;
  }

  .user-info {
    width: 100%;
  }

  .logout-btn {
    align-self: flex-end;
  }

  .stats-grid {
    grid-template-columns: 1fr;
    gap: 15px;
  }

  .add-todo-form {
    flex-direction: column;
    gap: 10px;
  }

  .add-btn {
    width: 100%;
    height: 45px;
  }

  .filter-tabs {
    justify-content: center;
  }

  .todo-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .todo-actions {
    align-self: flex-end;
  }

  .modal-content {
    margin: 20px;
    padding: 20px;
  }
}

@media (max-width: 480px) {
  .theme-toggle {
    top: 15px;
    right: 15px;
    width: 45px;
    height: 45px;
  }

  .user-details h1 {
    font-size: 1.5rem;
  }

  .stat-card {
    padding: 20px;
  }

  .stat-info h3 {
    font-size: 1.5rem;
  }

  .progress-card,
  .add-todo-card {
    padding: 20px;
  }

  .todo-item {
    padding: 15px;
  }
}