* {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
      }

      body {
        font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
          sans-serif;
        transition: background-color 0.3s, color 0.3s;
      }

      body.dark-mode {
        background-color: #0f172a;
        color: #e2e8f0;
      }

      .dark-mode .card {
        background-color: #1e293b;
        border-color: #334155;
      }

      .dark-mode .task-item {
        background-color: #1e293b;
        border-color: #334155;
      }

      .dark-mode .task-item:hover {
        background-color: #334155;
      }

      .dark-mode input,
      .dark-mode select,
      .dark-mode textarea {
        background-color: #334155;
        border-color: #475569;
        color: #e2e8f0;
      }

      .dark-mode .modal {
        background-color: rgba(0, 0, 0, 0.8);
      }

      .dark-mode .modal-content {
        background-color: #1e293b;
      }

      .priority-high {
        border-left: 4px solid #ef4444;
      }
      .priority-medium {
        border-left: 4px solid #f59e0b;
      }
      .priority-low {
        border-left: 4px solid #10b981;
      }

      .task-item {
        transition: all 0.2s ease;
        cursor: pointer;
      }

      .task-item:hover {
        transform: translateY(-2px);
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
      }

      .task-item.completed {
        opacity: 0.6;
      }

      .task-item.completed .task-title {
        text-decoration: line-through;
      }

      .modal {
        display: none;
        position: fixed;
        z-index: 1000;
        left: 0;
        top: 0;
        width: 100%;
        height: 100%;
        background-color: rgba(0, 0, 0, 0.5);
        animation: fadeIn 0.2s;
      }

      .modal.active {
        display: flex;
        align-items: center;
        justify-content: center;
      }

      .modal-content {
        background-color: white;
        border-radius: 12px;
        padding: 2rem;
        max-width: 600px;
        width: 90%;
        max-height: 90vh;
        overflow-y: auto;
        animation: slideUp 0.3s;
      }

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

      @keyframes slideUp {
        from {
          transform: translateY(50px);
          opacity: 0;
        }
        to {
          transform: translateY(0);
          opacity: 1;
        }
      }

      .badge {
        display: inline-block;
        padding: 0.25rem 0.75rem;
        border-radius: 9999px;
        font-size: 0.75rem;
        font-weight: 600;
      }

      .badge-pending {
        background-color: #dbeafe;
        color: #1e40af;
      }
      .badge-progress {
        background-color: #fef3c7;
        color: #92400e;
      }
      .badge-completed {
        background-color: #d1fae5;
        color: #065f46;
      }

      .dark-mode .badge-pending {
        background-color: #1e3a8a;
        color: #bfdbfe;
      }
      .dark-mode .badge-progress {
        background-color: #78350f;
        color: #fef3c7;
      }
      .dark-mode .badge-completed {
        background-color: #064e3b;
        color: #a7f3d0;
      }

      .stat-card {
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        color: white;
        border-radius: 12px;
        padding: 1.5rem;
        transition: transform 0.2s;
      }

      .stat-card:hover {
        transform: translateY(-4px);
      }

      .stat-card.green {
        background: linear-gradient(135deg, #10b981 0%, #059669 100%);
      }
      .stat-card.red {
        background: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
      }
      .stat-card.blue {
        background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
      }
      .stat-card.purple {
        background: linear-gradient(135deg, #8b5cf6 0%, #7c3aed 100%);
      }

      .progress-bar {
        height: 8px;
        background-color: #e5e7eb;
        border-radius: 9999px;
        overflow: hidden;
      }

      .dark-mode .progress-bar {
        background-color: #374151;
      }

      .progress-fill {
        height: 100%;
        background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
        transition: width 0.5s ease;
      }

      .filter-btn {
        padding: 0.5rem 1rem;
        border-radius: 8px;
        border: 2px solid transparent;
        transition: all 0.2s;
        cursor: pointer;
      }

      .filter-btn:hover {
        background-color: #f3f4f6;
      }

      .dark-mode .filter-btn:hover {
        background-color: #334155;
      }

      .filter-btn.active {
        background-color: #667eea;
        color: white;
        border-color: #667eea;
      }

      .timer {
        font-family: "Courier New", monospace;
        font-size: 1.25rem;
        font-weight: bold;
      }

      .subtask-item {
        padding: 0.5rem;
        border-left: 2px solid #e5e7eb;
        margin-left: 1rem;
      }

      .dark-mode .subtask-item {
        border-color: #475569;
      }

      .tag {
        display: inline-block;
        padding: 0.25rem 0.5rem;
        background-color: #f3f4f6;
        border-radius: 4px;
        font-size: 0.75rem;
        margin-right: 0.25rem;
      }

      .dark-mode .tag {
        background-color: #374151;
      }

      .calendar-day {
        aspect-ratio: 1;
        padding: 0.5rem;
        border: 1px solid #e5e7eb;
        cursor: pointer;
        transition: all 0.2s;
      }

      .calendar-day:hover {
        background-color: #f9fafb;
      }

      .dark-mode .calendar-day {
        border-color: #374151;
      }

      .dark-mode .calendar-day:hover {
        background-color: #1e293b;
      }

      .calendar-day.has-tasks {
        background-color: #ede9fe;
      }

      .dark-mode .calendar-day.has-tasks {
        background-color: #2e1065;
      }

      .scrollbar-thin::-webkit-scrollbar {
        width: 6px;
      }

      .scrollbar-thin::-webkit-scrollbar-track {
        background: #f1f1f1;
      }

      .scrollbar-thin::-webkit-scrollbar-thumb {
        background: #888;
        border-radius: 3px;
      }

      .scrollbar-thin::-webkit-scrollbar-thumb:hover {
        background: #555;
      }

      /* Authentication UI Styles */
      #authStatus {
        transition: all 0.3s ease;
      }

      #loginBtn, #logoutBtn {
        transition: all 0.2s ease;
      }

      #loginBtn:hover {
        transform: translateY(-1px);
        box-shadow: 0 4px 8px rgba(139, 92, 246, 0.3);
      }

      #logoutBtn:hover {
        transform: translateY(-1px);
        box-shadow: 0 4px 8px rgba(220, 38, 38, 0.3);
      }

      #authError {
        animation: shake 0.5s;
      }

      @keyframes shake {
        0%, 100% { transform: translateX(0); }
        25% { transform: translateX(-10px); }
        75% { transform: translateX(10px); }
      }

      .dark-mode #authError {
        background-color: #7f1d1d;
        border-color: #991b1b;
        color: #fca5a5;
      }

      #googleAuthBtn:hover {
        border-color: #4285f4;
        background-color: #f8f9fa;
      }

      .dark-mode #googleAuthBtn {
        background-color: #1e293b;
        border-color: #475569;
        color: #e2e8f0;
      }

      .dark-mode #googleAuthBtn:hover {
        background-color: #334155;
        border-color: #64748b;
      }

      #githubAuthBtn:hover {
        background-color: #1f2937;
      }

      .dark-mode #githubAuthBtn {
        background-color: #0f172a;
      }

      .dark-mode #githubAuthBtn:hover {
        background-color: #1e293b;
      }

      /* Enhanced Responsive Design */
      @media (max-width: 768px) {
        .container {
          padding-left: 1rem;
          padding-right: 1rem;
        }

        header .container {
          padding: 1rem;
        }

        h1 {
          font-size: 1.5rem;
        }

        .stat-card {
          padding: 1rem;
        }

        .modal-content {
          padding: 1.5rem;
          width: 95%;
          max-height: 95vh;
        }

        .auth-modal-content {
          padding: 1.5rem;
        }

        #loginBtn, #logoutBtn {
          padding: 0.5rem 1rem;
          font-size: 0.875rem;
        }

        #loginBtn i, #logoutBtn i {
          margin-right: 0.25rem;
        }

        .filter-btn {
          padding: 0.375rem 0.75rem;
          font-size: 0.875rem;
        }

        .task-item {
          padding: 1rem;
        }
      }

      @media (max-width: 640px) {
        header .flex {
          flex-wrap: wrap;
        }

        header .flex > div:first-child {
          width: 100%;
          margin-bottom: 0.5rem;
        }

        header .flex > div:last-child {
          width: 100%;
          justify-content: space-between;
        }

        .grid-cols-1.md\:grid-cols-2.lg\:grid-cols-4 {
          grid-template-columns: 1fr;
        }

        .grid-cols-2 {
          grid-template-columns: 1fr;
        }

        #authStatus {
          display: none;
        }

        .auth-tab {
          font-size: 0.875rem;
          padding: 0.75rem 0.5rem;
        }

        .auth-tab i {
          display: none;
        }

        .modal-content {
          padding: 1rem;
        }

        .task-item {
          flex-direction: column;
          align-items: flex-start;
        }

        .task-item .flex {
          width: 100%;
          margin-top: 0.5rem;
        }
      }

      /* Enhanced Modal Styles */
      .auth-modal-content {
        max-width: 450px;
        width: 100%;
      }

      .auth-tab {
        position: relative;
        cursor: pointer;
      }

      .auth-tab.active {
        color: #9333ea;
      }

      .auth-tab:not(.active) {
        color: #6b7280;
      }

      .dark-mode .auth-tab:not(.active) {
        color: #9ca3af;
      }

      /* Improved Button Styles */
      button:focus {
        outline: 2px solid #9333ea;
        outline-offset: 2px;
      }

      /* Enhanced Input Styles */
      input:focus, select:focus, textarea:focus {
        outline: none;
        box-shadow: 0 0 0 3px rgba(147, 51, 234, 0.1);
      }

      /* Smooth Transitions */
      * {
        transition-property: color, background-color, border-color, transform, box-shadow;
        transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
        transition-duration: 150ms;
      }

      /* Touch-friendly on mobile */
      @media (hover: none) and (pointer: coarse) {
        button, .task-item, .filter-btn {
          min-height: 44px;
          min-width: 44px;
        }
      }

      /* Improved Scrollbar for Dark Mode */
      .dark-mode .scrollbar-thin::-webkit-scrollbar-track {
        background: #1e293b;
      }

      .dark-mode .scrollbar-thin::-webkit-scrollbar-thumb {
        background: #475569;
      }

      .dark-mode .scrollbar-thin::-webkit-scrollbar-thumb:hover {
        background: #64748b;
      }

      /* Loading States */
      .loading {
        opacity: 0.6;
        pointer-events: none;
      }

      /* Enhanced Card Shadows */
      .stat-card, .task-item, .modal-content {
        box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
      }

      .stat-card:hover, .task-item:hover {
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
      }

      .dark-mode .stat-card, .dark-mode .task-item, .dark-mode .modal-content {
        box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.3), 0 1px 2px 0 rgba(0, 0, 0, 0.2);
      }

      /* Better Mobile Header */
      @media (max-width: 640px) {
        header h1 {
          font-size: 1.25rem;
        }

        header p {
          font-size: 0.75rem;
        }

        #loginBtn span, #logoutBtn span {
          display: none;
        }

        #loginBtn, #logoutBtn {
          padding: 0.5rem;
          min-width: 44px;
        }
      }