:root {
      --primary-color: #000000;
      --primary-light: #000000;
      --secondary-color: #000000;
      --text-color: #333;
      --text-light: #666;
      --background-color: #f9f9f9;
      --card-color: #fff;
      --border-color: #eaeaea;
      --success-color: #4caf50;
      --warning-color: #ff9800;
      --danger-color: #f44336;
      --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
      --border-radius: 12px;
    }

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

    body {
      font-family: "Poppins", sans-serif;
      background-color: var(--background-color);
      color: var(--text-color);
      line-height: 1.6;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 2rem;
    }

    header {
      text-align: center;
      margin-bottom: 2rem;
    }

    h1 {
      font-size: 2.5rem;
      color: var(--primary-color);
      margin-bottom: 0.5rem;
    }

    .subtitle {
      color: var(--text-light);
      font-size: 1.1rem;
    }

    main {
      display: grid;
      grid-template-columns: 1fr;
      gap: 2rem;
    }

    @media (min-width: 768px) {
      main {
        grid-template-columns: 1fr 1fr;
      }
    }

    /* Timer Section */
    .timer-section {
      display: flex;
      justify-content: center;
    }

    .timer-container {
      background-color: var(--card-color);
      border-radius: var(--border-radius);
      padding: 2rem;
      box-shadow: var(--shadow);
      text-align: center;
      width: 100%;
    }

    .timer-display {
      font-size: 5rem;
      font-weight: 700;
      margin-bottom: 1rem;
      color: var(--primary-color);
    }

    .timer-label {
      font-size: 1.2rem;
      color: var(--text-light);
      margin-bottom: 1.5rem;
    }

    .timer-controls {
      display: flex;
      justify-content: center;
      gap: 1rem;
      margin-bottom: 1.5rem;
    }

    .timer-mode {
      display: flex;
      justify-content: center;
      gap: 0.5rem;
    }

    .mode-btn {
      background-color: transparent;
      border: none;
      padding: 0.5rem 1rem;
      border-radius: 20px;
      cursor: pointer;
      font-family: inherit;
      font-size: 0.9rem;
      transition: all 0.3s ease;
    }

    .mode-btn.active {
      background-color: var(--primary-light);
      color: #fff;
      font-weight: 500;
    }

    /* Tasks Section */
    .tasks-section {
      display: flex;
      flex-direction: column;
    }

    .tasks-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 1.5rem;
    }

    .tasks-header h2 {
      font-size: 1.8rem;
      color: var(--text-color);
    }

    .task-filters {
      display: flex;
      gap: 0.5rem;
      margin-bottom: 1.5rem;
      overflow-x: auto;
      padding-bottom: 0.5rem;
    }

    .filter-btn {
      background-color: transparent;
      border: none;
      padding: 0.5rem 1rem;
      border-radius: 20px;
      cursor: pointer;
      font-family: inherit;
      font-size: 0.9rem;
      transition: all 0.3s ease;
      white-space: nowrap;
    }

    .filter-btn.active {
      background-color: var(--primary-light);
      color: #fff;
      font-weight: 500;
    }

    .tasks-container {
      background-color: var(--card-color);
      border-radius: var(--border-radius);
      padding: 1.5rem;
      box-shadow: var(--shadow);
      flex-grow: 1;
      overflow-y: auto;
      max-height: 500px;
    }

    .task-item {
      background-color: var(--background-color);
      border-radius: 8px;
      padding: 1rem;
      margin-bottom: 1rem;
      position: relative;
      border-left: 4px solid transparent;
      transition: all 0.3s ease;
    }

    .task-item.important {
      border-left-color: var(--secondary-color);
    }

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

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

    .task-header {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      margin-bottom: 0.5rem;
    }

    .task-title {
      font-weight: 500;
      font-size: 1.1rem;
      margin-right: 1rem;
    }

    .task-actions {
      display: flex;
      gap: 0.5rem;
    }

    .task-action-btn {
      background: none;
      border: none;
      cursor: pointer;
      font-size: 1rem;
      color: var(--text-light);
      transition: color 0.3s ease;
    }

    .task-action-btn:hover {
      color: var(--primary-color);
    }

    .task-description {
      color: var(--text-light);
      font-size: 0.9rem;
      margin-bottom: 0.5rem;
    }

    .task-meta {
      display: flex;
      justify-content: space-between;
      font-size: 0.8rem;
      color: var(--text-light);
    }

    .task-category {
      background-color: var(--primary-light);
      color: #fff;
      padding: 0.2rem 0.5rem;
      border-radius: 12px;
      font-size: 0.8rem;
    }

    .task-category.work {
      background-color: #e8f5e9;
      color: #4caf50;
    }

    .task-category.personal {
      background-color: #fff8e1;
      color: #ffc107;
    }

    .task-category.other {
      background-color: #e3f2fd;
      color: #2196f3;
    }

    /* Buttons */
    .btn {
      padding: 0.6rem 1.2rem;
      border: none;
      border-radius: 6px;
      cursor: pointer;
      font-family: inherit;
      font-weight: 500;
      transition: all 0.3s ease;
    }

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

    .btn.primary:hover {
      background-color: #ffffff;
      color: var(--primary-color);
      border: 1px solid var(--primary-color);
      box-shadow: var(--shadow);
    }

    .btn.secondary {
      background-color: #f0f0f0;
      color: var(--text-color);
    }

    .btn.secondary:hover {
      background-color: #e0e0e0;
    }

    .btn:disabled {
      opacity: 0.6;
      cursor: not-allowed;
    }

    /* Modal */
    .modal {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-color: rgba(0, 0, 0, 0.5);
      z-index: 1000;
      justify-content: center;
      align-items: center;
    }

    .modal-content {
      background-color: var(--card-color);
      border-radius: var(--border-radius);
      padding: 2rem;
      width: 90%;
      max-width: 500px;
      position: relative;
      box-shadow: var(--shadow);
    }

    .close-modal {
      position: absolute;
      top: 1rem;
      right: 1.5rem;
      font-size: 1.5rem;
      cursor: pointer;
      color: var(--text-light);
    }

    .form-group {
      margin-bottom: 1.5rem;
    }

    .form-group label {
      display: block;
      margin-bottom: 0.5rem;
      color: var(--text-color);
      font-weight: 500;
    }

    .form-group input,
    .form-group textarea,
    .form-group select {
      width: 100%;
      padding: 0.8rem;
      border: 1px solid var(--border-color);
      border-radius: 6px;
      font-family: inherit;
      font-size: 1rem;
    }

    .form-group textarea {
      resize: vertical;
      min-height: 100px;
    }

    .checkbox-group {
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    .checkbox-group label {
      margin-bottom: 0;
    }

    .checkbox-group input {
      width: auto;
    }

    .form-actions {
      display: flex;
      justify-content: flex-end;
      gap: 1rem;
    }

    /* Empty state */
    .empty-state {
      text-align: center;
      padding: 2rem;
      color: var(--text-light);
    }

    .empty-state p {
      margin-bottom: 1rem;
    }

    /* Responsive adjustments */
    @media (max-width: 767px) {
      .timer-display {
        font-size: 4rem;
      }

      .timer-controls,
      .timer-mode {
        flex-wrap: wrap;
      }

      .tasks-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
      }

      .task-filters {
        width: 100%;
      }
    }