:root {
    --bg-page: #F8FAFC;
    --bg-hero-start: #F0FDFA;
    --bg-hero-end: #F1F5F9;
    --bg-card: #FFFFFF;
    --primary-accent: #0D9488;
    --primary-accent-light: #CCFBF1;
    --text-dark: #1E293B;
    --text-medium: #475569;
    --text-light: #94A3B8;
    --border-color: #E2E8F0;
    --success-bg: #ECFDF5;
    --success-text: #065F46;
  }
  
  * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  
  body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-page);
    color: var(--text-medium);
    line-height: 1.6;
  }
  
  /* Navigation */
  .navbar {
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 1rem 0;
  }
  
  .nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
  }
  
  .nav-logo {
    width: 32px;
    height: 32px;
  }
  
  .brand-name {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-dark);
  }
  
  .brand-link {
    text-decoration: none;
    color: inherit;
    display: flex;
    align-items: center;
    gap: 0.75rem;
  }
  
  /* Navigation Toggle */
  .nav-toggle {
    display: flex;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    gap: 0.25rem;
  }
  
  .nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--text-dark);
    transition: all 0.3s ease;
    transform-origin: center;
  }
  
  /* Navigation Slider */
  .nav-slider {
    position: fixed;
    top: 0;
    right: -100%;
    width: 300px;
    height: 100vh;
    background-color: var(--bg-card);
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.1);
    transition: right 0.3s ease-in-out;
    z-index: 1001;
  }
  
  .nav-slider.active {
    right: 0;
  }
  
  .slider-content {
    padding: 1.5rem;
    height: 100%;
  }
  
  .slider-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
  }
  
  .slider-close {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text-dark);
    cursor: pointer;
    padding: 0.5rem;
  }
  
  .slider-links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .slider-link {
    display: block;
    padding: 1rem;
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    border-radius: 0.5rem;
    transition: all 0.2s;
  }
  
  .slider-link:hover {
    background-color: var(--primary-accent-light);
    color: var(--primary-accent);
  }
  
  .nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
  }
  
  .nav-overlay.active {
    opacity: 1;
    visibility: visible;
  }
  
  /* Container */
  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
  }
  
  /* Hero Section */
  .hero-section {
    padding: 4rem 1rem;
    background: linear-gradient(120deg, var(--bg-hero-start), var(--bg-hero-end));
    text-align: center;
  }
  
  .hero-content {
    max-width: 800px;
    margin: 0 auto;
  }
  
  .hero-text h1 {
    font-size: clamp(1.75rem, 5vw, 2.5rem);
    font-weight: 800;
    margin-bottom: 1rem;
    color: var(--text-dark);
  }
  
  .hero-text p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    color: var(--text-dark);
  }
  
  .quick-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin: 2.5rem 0;
    flex-wrap: wrap;
  }
  
  .stat {
    text-align: center;
  }
  
  .stat-number {
    display: block;
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--primary-accent);
    margin-bottom: 0.25rem;
  }
  
  .stat-label {
    font-size: 0.875rem;
    color: var(--text-medium);
    font-weight: 500;
  }
  
  .hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
  }
  
  .cta-button {
    display: inline-block;
    padding: 1rem 2rem;
    border-radius: 0.5rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
    border: none;
    cursor: pointer;
  }
  
  .cta-button.primary {
    background-color: var(--primary-accent);
    color: white;
  }
  
  .cta-button.primary:hover {
    background-color: #0b8378;
    transform: translateY(-2px);
  }
  
  .cta-button.secondary {
    background-color: transparent;
    color: var(--primary-accent);
    border: 2px solid var(--primary-accent);
  }
  
  .cta-button.secondary:hover {
    background-color: var(--primary-accent-light);
  }
  
  /* Main Calculator */
  .calculator-container {
    padding: 4rem 0;
  }
  
  .section-title {
    font-size: clamp(1.5rem, 4vw, 2rem);
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 1rem;
    text-align: center;
  }
  
  .section-subtitle {
    text-align: center;
    color: var(--text-medium);
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
  }
  
  .card {
    background: var(--bg-card);
    border-radius: 1rem;
    padding: 2rem;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
  }
  
  .main-card {
    border-top: 4px solid var(--primary-accent);
  }
  
  /* Tool Tabs */
  .tool-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 2rem;
    flex-wrap: wrap;
  }
  
  .tool-tab {
    padding: 1rem 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    font-weight: 500;
    color: var(--text-medium);
    border-bottom: 2px solid transparent;
    transition: all 0.2s;
    white-space: nowrap;
  }
  
  .tool-tab.active {
    color: var(--primary-accent);
    border-bottom-color: var(--primary-accent);
  }
  
  .tool-tab:hover:not(.active) {
    color: var(--primary-accent);
  }
  
  .tool-content {
    display: none;
  }
  
  .tool-content.active {
    display: block;
  }
  
  .tool-content h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-dark);
  }
  
  .tool-content p {
    margin-bottom: 1.5rem;
    color: var(--text-medium);
  }
  
  /* Courses Container */
  .courses-container {
    margin-bottom: 1.5rem;
  }
  
  .course-row {
    display: grid;
    grid-template-columns: 2fr 1.5fr 1fr 1fr auto;
    gap: 1rem;
    align-items: center;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    margin-bottom: 0.75rem;
    background: var(--bg-page);
  }
  
  .course-name {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 0.875rem;
  }
  
  .course-grade, .course-weight, .course-credits {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 0.875rem;
    background: white;
  }
  
  .remove-course {
    background: none;
    border: none;
    color: var(--text-light);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 0.25rem;
    transition: all 0.2s;
  }
  
  .remove-course:hover {
    color: #dc2626;
    background: #fef2f2;
  }
  
  .add-course-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--primary-accent-light);
    color: var(--primary-accent);
    border: 1px dashed var(--primary-accent);
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    margin-bottom: 2rem;
  }
  
  .add-course-btn:hover {
    background: var(--primary-accent);
    color: white;
  }
  
  /* Input Sections */
  .semester-container {
    display: grid;
    gap: 2rem;
    margin-bottom: 2rem;
  }
  
  .semester-section {
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    background: var(--bg-page);
  }
  
  .semester-section h4 {
    margin-bottom: 1rem;
    color: var(--text-dark);
  }
  
  .input-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
  }
  
  .input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .input-group label {
    font-weight: 500;
    color: var(--text-dark);
    font-size: 0.875rem;
  }
  
  .input-group input {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1rem;
  }
  
  .input-group input:focus {
    outline: none;
    border-color: var(--primary-accent);
    box-shadow: 0 0 0 3px var(--primary-accent-light);
  }
  
  /* Results */
  .calculation-results {
    margin-top: 2rem;
  }
  
  .result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
  }
  
  .result-card {
    text-align: center;
    padding: 2rem;
    background: var(--success-bg);
    border: 1px solid var(--success-text);
    border-radius: 0.75rem;
  }
  
  .result-card h4 {
    margin-bottom: 1rem;
    color: var(--success-text);
    font-size: 1.1rem;
  }
  
  .gpa-display {
    font-size: 3rem;
    font-weight: 800;
    color: var(--primary-accent);
    margin-bottom: 0.5rem;
  }
  
  .result-card p {
    color: var(--success-text);
    font-size: 0.875rem;
  }
  
  /* Content Sections */
  .content-section {
    padding: 4rem 0;
    background: var(--bg-page);
  }
  
  .content-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
  }
  
  .content-card {
    padding: 2rem;
    background: var(--bg-card);
    border-radius: 1rem;
    border: 1px solid var(--border-color);
  }
  
  .content-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-dark);
  }
  
  .content-card p {
    color: var(--text-medium);
    line-height: 1.6;
  }
  
  /* FAQ Section */
  .faq-section {
    padding: 4rem 0;
    background: var(--bg-hero-end);
  }
  
  .faq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
  }
  
  .faq-item {
    padding: 2rem;
    background: var(--bg-card);
    border-radius: 1rem;
    border: 1px solid var(--border-color);
  }
  
  .faq-item h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-dark);
  }
  
  .faq-item p {
    color: var(--text-medium);
    line-height: 1.6;
  }
  
  /* SEO Content Section */
  .seo-content-section {
    padding: 4rem 0;
    background: var(--bg-page);
  }
  
  .seo-content-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
  }
  
  .seo-content-card {
    padding: 2rem;
    background: var(--bg-card);
    border-radius: 1rem;
    border: 1px solid var(--border-color);
  }
  
  .seo-content-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-dark);
  }
  
  .seo-content-card p {
    color: var(--text-medium);
    line-height: 1.6;
  }
  
  /* Footer */
  .footer {
    background: var(--text-dark);
    color: white;
    padding: 3rem 0 1rem;
  }
  
  .footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
  }
  
  .footer-section {
    display: flex;
    flex-direction: column;
  }
  
  .footer-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
  }
  
  .footer-logo {
    width: 32px;
    height: 32px;
  }
  
  .footer-description {
    color: #94a3b8;
    line-height: 1.6;
  }
  
  .footer-heading {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
  }
  
  .footer-links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .footer-links a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.2s;
  }
  
  .footer-links a:hover {
    color: white;
  }
  
  .footer-bottom {
    border-top: 1px solid #334155;
    padding-top: 1.5rem;
    text-align: center;
    color: #94a3b8;
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.5rem 1rem 0;
  }
  
  /* Animations */
  .animate-on-load {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeIn 0.8s ease forwards;
  }
  
  @keyframes fadeIn {
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  /* Responsive Design */
  @media (max-width: 768px) {
    .nav-slider {
      width: 100%;
    }
    
    .tool-tabs {
      flex-direction: column;
    }
    
    .tool-tab {
      text-align: center;
    }
    
    .course-row {
      grid-template-columns: 1fr;
      gap: 0.75rem;
    }
    
    .input-section {
      grid-template-columns: 1fr;
    }
    
    .result-grid {
      grid-template-columns: 1fr;
    }
    
    .content-grid,
    .faq-grid,
    .seo-content-grid {
      grid-template-columns: 1fr;
    }
    
    .hero-buttons {
      flex-direction: column;
      align-items: center;
    }
    
    .cta-button {
      width: 100%;
      max-width: 300px;
      text-align: center;
    }
    
    .quick-stats {
      gap: 1.5rem;
    }
  }
  
  @media (max-width: 480px) {
    .card {
      padding: 1.5rem;
    }
    
    .course-row {
      padding: 0.75rem;
    }
    
    .gpa-display {
      font-size: 2.5rem;
    }
    
    .content-card,
    .faq-item,
    .seo-content-card {
      padding: 1.5rem;
    }
  }
  /* Add to existing CSS */

/* Data Management */
.data-management-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin: 2rem 0;
    flex-wrap: wrap;
  }
  
  .data-button {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--primary-accent-light);
    color: var(--primary-accent);
    border: 1px solid var(--primary-accent);
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
  }
  
  .data-button:hover {
    background: var(--primary-accent);
    color: white;
    transform: translateY(-2px);
  }
  
  .data-warning {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--warning-bg);
    color: var(--warning-text);
    border: 1px solid var(--warning-text);
    border-radius: 0.5rem;
    margin: 1rem 0 2rem;
    font-size: 0.875rem;
  }
  
  .data-warning i {
    color: var(--warning-text);
  }
  
  /* Loading Indicator */
  .loading-indicator {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem;
    background: var(--info-bg);
    color: var(--info-text);
    border: 1px solid var(--info-text);
    border-radius: 0.5rem;
    margin: 1rem 0;
    justify-content: center;
  }
  
  .loading-spinner {
    width: 20px;
    height: 20px;
    border: 2px solid transparent;
    border-top: 2px solid var(--info-text);
    border-radius: 50%;
    animation: spin 1s linear infinite;
  }
  
  @keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
  }
  
  /* Modal Styles */
  .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: 2000;
  }
  
  .modal-content {
    background: white;
    border-radius: 1rem;
    padding: 0;
    max-width: 500px;
    width: 90%;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  }
  
  .modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
  }
  
  .modal-header h3 {
    margin: 0;
    color: var(--text-dark);
  }
  
  .modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
    padding: 0.25rem;
  }
  
  .modal-close:hover {
    color: var(--text-dark);
  }
  
  .modal-body {
    padding: 1.5rem;
  }
  
  .modal-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--border-color);
  }
  
  /* Course limit warning */
  .course-limit-warning {
    background: var(--warning-bg);
    color: var(--warning-text);
    border: 1px solid var(--warning-text);
    padding: 0.75rem;
    border-radius: 0.5rem;
    margin: 1rem 0;
    text-align: center;
    font-size: 0.875rem;
  }
  
  .course-limit-warning i {
    margin-right: 0.5rem;
  }
  
  /* Print Styles */
  @media print {
    .navbar,
    .data-management-buttons,
    .data-warning,
    .tool-tabs,
    .add-course-btn,
    .remove-course,
    .footer {
      display: none !important;
    }
    
    .card {
      border: none !important;
      box-shadow: none !important;
    }
    
    .course-row {
      break-inside: avoid;
    }
    
    body {
      background: white !important;
      color: black !important;
    }
    
    .gpa-display {
      color: black !important;
      font-size: 2rem !important;
    }
  }
  /* Add to existing CSS */

/* Guide Section */
.guide-content {
    max-width: 800px;
    margin: 0 auto;
  }
  
  .guide-section {
    margin-bottom: 3rem;
    padding: 2rem;
    background: var(--bg-card);
    border-radius: 1rem;
    border: 1px solid var(--border-color);
  }
  
  .guide-section h3 {
    color: var(--text-dark);
    margin-bottom: 1rem;
    font-size: 1.5rem;
  }
  
  .guide-section p {
    margin-bottom: 1rem;
    line-height: 1.7;
  }
  
  .guide-section ul, .guide-section ol {
    margin: 1rem 0;
    padding-left: 1.5rem;
  }
  
  .guide-section li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
  }
  
  .formula-box {
    background: var(--primary-accent-light);
    border: 2px solid var(--primary-accent);
    border-radius: 0.5rem;
    padding: 1.5rem;
    margin: 1.5rem 0;
    text-align: center;
    font-family: 'Courier New', monospace;
    font-size: 1.1rem;
  }
  
  .comparison-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
  }
  
  .comparison-card {
    padding: 1.5rem;
    background: var(--bg-page);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
  }
  
  .comparison-card h4 {
    color: var(--primary-accent);
    margin-bottom: 1rem;
    text-align: center;
  }
  
  .comparison-card ul {
    list-style: none;
    padding: 0;
  }
  
  .comparison-card li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
  }
  
  .comparison-card li:last-child {
    border-bottom: none;
  }
  
  /* Content Links */
  .content-links {
    margin-top: 3rem;
    padding: 2rem;
    background: var(--bg-card);
    border-radius: 1rem;
    text-align: center;
  }
  
  .content-links h3 {
    margin-bottom: 1.5rem;
    color: var(--text-dark);
  }
  
  .related-links {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
  }
  
  .content-link {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: var(--primary-accent-light);
    color: var(--primary-accent);
    text-decoration: none;
    border-radius: 0.5rem;
    font-weight: 500;
    transition: all 0.2s;
  }
  
  .content-link:hover {
    background: var(--primary-accent);
    color: white;
    transform: translateY(-2px);
  }
  
  /* Dismissible warning */
  .data-warning {
    position: relative;
    padding-right: 3rem;
  }
  
  .dismiss-warning {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--warning-text);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 0.25rem;
  }
  
  .dismiss-warning:hover {
    background: rgba(0,0,0,0.1);
  }
  
  /* Keyboard navigation */
  .remove-course:focus {
    outline: 2px solid var(--primary-accent);
    outline-offset: 2px;
  }
  
  .course-row:focus-within {
    border-color: var(--primary-accent);
    box-shadow: 0 0 0 2px var(--primary-accent-light);
  }
  
  /* Auto-save indicator */
  .auto-save-indicator {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 0.5rem 1rem;
    background: var(--success-bg);
    color: var(--success-text);
    border: 1px solid var(--success-text);
    border-radius: 0.5rem;
    font-size: 0.875rem;
    z-index: 1000;
    opacity: 0;
    transform: translateY(10px);
    transition: all 0.3s ease;
  }
  
  .auto-save-indicator.show {
    opacity: 1;
    transform: translateY(0);
  }
  
  /* Enhanced CSV export results */
  .csv-results-section {
    margin-top: 1rem;
    padding: 1rem;
    background: var(--info-bg);
    border: 1px solid var(--info-text);
    border-radius: 0.5rem;
  }
  
  .csv-results-section h5 {
    margin: 0 0 0.5rem 0;
    color: var(--info-text);
  }
  
  /* Responsive improvements */
  @media (max-width: 768px) {
    .guide-section {
      padding: 1.5rem;
    }
    
    .comparison-grid {
      grid-template-columns: 1fr;
    }
    
    .related-links {
      flex-direction: column;
      align-items: center;
    }
    
    .content-link {
      width: 100%;
      max-width: 250px;
      text-align: center;
    }
    
    .data-management-buttons {
      flex-direction: column;
    }
    
    .data-button {
      justify-content: center;
    }
  }
  
  @media (max-width: 480px) {
    .guide-section {
      padding: 1rem;
    }
    
    .formula-box {
      padding: 1rem;
      font-size: 0.9rem;
    }
  }