/* Utilizing modern CSS layers for better organization */
@layer reset, theme, base, layout, modules, utilities;

@layer reset {
  *,
  *::before,
  *::after {
    box-sizing: border-box;
  }
  
  body {
    margin: unset;
  }
  
  button,
  input,
  textarea,
  select {
    font: inherit;
  }
  
  img,
  picture,
  svg,
  canvas {
    display: block;
    max-inline-size: 100%;
    height: auto;
  }
  
  @media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
      animation-duration: 0.01ms !important;
      animation-iteration-count: 1 !important;
      transition-duration: 0.01ms !important;
      scroll-behavior: auto !important;
    }
  }
}

@layer theme {
  :root {
    /* Color scheme - clean and accessible */
    --background-color: #ffffff;
    --text-color: #1a1a1a;
    --text-secondary: #666666;
    --highlight-high: #f8f9fa;
    --color-primary: #007bff;
    --color-primary-hover: #0056b3;
    --color-success: #28a745;
    --color-success-hover: #1e7e34;
    --color-danger: #dc3545;
    --color-danger-hover: #c82333;
    --color-border: #dee2e6;
    --color-border-light: #e9ecef;
    --color-shadow: rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-main: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-monospace: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
    
    /* Layout */
    --column-size: 800px;
    --margin-y: 1rem;
    --border-radius: 0.5rem;
    --border-radius-sm: 0.25rem;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
  }
}

@layer base {
  :root {
    font-size: clamp(1rem, 0.4rem + 0.8svw, 1.2rem);
  }
  
  body {
    font-family: var(--font-main);
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
  }
  
  a:any-link {
    color: var(--color-primary);
    text-decoration: unset;
  }
  
  a:any-link:hover {
    color: var(--color-primary-hover);
  }
  
  h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-main);
    margin: unset;
    font-weight: 600;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.65rem;
  }
  
  h3 {
    font-size: 1.3rem;
  }
  
  @media (min-width: 768px) {
    h1 {
      font-size: 2.2rem;
    }
    
    h2 {
      font-size: 1.85rem;
    }
    
    h3 {
      font-size: 1.5rem;
    }
  }
  
  p {
    margin: var(--margin-y) 0;
  }
  
  ul {
    margin: var(--margin-y) 0;
    padding-inline-start: 1.25rem;
  }
  
  li + li {
    margin-block-start: 0.5em;
  }
  
  @media (min-width: 768px) {
    li + li {
      margin-block-start: 0.3em;
    }
  }
}

@layer layout {
  body .container {
    margin: 5px 5px 0;
  }
  
  @media (min-width: 768px) {
    body .container {
      max-width: 1200px;
      margin: 10px auto 0;
    }
  }
  
  .header {
    background: var(--color-primary);
    color: white;
    padding: var(--space-md) 0;
    margin-block-end: var(--space-lg);
  }
  
  .header-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
  }
  
  .header h1 {
    margin: 0;
    font-size: 2rem;
    font-weight: 600;
    text-align: center;
    order: 2;
  }
  
  .nav-back {
    order: 1;
    align-self: flex-start;
  }
  
  @media (min-width: 768px) {
    .header-content {
      flex-direction: row;
      justify-content: space-between;
      align-items: center;
    }
    
    .header h1 {
      order: 2;
      flex: 1;
      text-align: right;
    }
    
    .nav-back {
      order: 1;
      flex-shrink: 0;
    }
  }
  
  .card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 8px var(--color-shadow);
    padding: var(--space-lg);
    margin-block-end: var(--space-lg);
    border: 1px solid var(--color-border-light);
  }
}

@layer modules {
  .btn {
    display: inline-block;
    padding: var(--space-sm) var(--space-md);
    background: var(--color-primary);
    color: white;
    text-decoration: none;
    border-radius: var(--border-radius-sm);
    border: none;
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    transition: background-color 0.2s ease;
  }
  
  .btn:hover {
    background: var(--color-primary-hover);
  }
  
  .btn-success {
    background: var(--color-success);
  }
  
  .btn-success:hover {
    background: var(--color-success-hover);
  }
  
  .btn-danger {
    background: var(--color-danger);
  }
  
  .btn-danger:hover {
    background: var(--color-danger-hover);
  }
  
  .btn:disabled {
    background: var(--text-secondary);
    cursor: not-allowed;
  }
  
  .form-control {
    width: 100%;
    padding: var(--space-sm);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    margin-block-end: var(--space-sm);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
  }
  
  .form-control:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
  }
  
  .alert {
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--border-radius-sm);
    margin-block-end: var(--space-md);
    border: 1px solid;
  }
  
  .alert-success {
    background: #d4edda;
    color: #155724;
    border-color: #c3e6cb;
  }
  
  .alert-error {
    background: #f8d7da;
    color: #721c24;
    border-color: #f5c6cb;
  }
  
  .slot-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-md);
    margin-block-start: var(--space-lg);
  }
  
  @media (min-width: 768px) {
    .slot-grid {
      grid-template-columns: repeat(3, 1fr);
      gap: var(--space-lg);
    }
  }
  
  .slot-card {
    display: flex;
    flex-direction: column;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--space-md);
    background: white;
    transition: box-shadow 0.2s ease;
  }
  
  .slot-card:hover {
    box-shadow: 0 4px 12px var(--color-shadow);
  }
  
  .slot-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-block-end: var(--space-sm);
  }
  
  .slot-title {
    font-weight: 600;
    font-size: 1rem;
  }
  
  .slot-status {
    margin-left: var(--space-xs);
    padding: var(--space-xs) var(--space-sm);
    border-radius: 1rem;
    font-size: 0.75rem;
    font-weight: 600;
    text-align: center;
    min-width: 80px
  }

  .slot-action {
    margin-top: auto;
    text-align: center;
  }

  .slot-action .btn {
    width: 100%;
  }
  
  .status-available {
    background: #d4edda;
    color: #155724;
  }
  
  .status-full {
    background: #f8d7da;
    color: #721c24;
  }
  
  .slot-details {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-block-end: var(--space-sm);
  }
  
  .signup-list {
    margin-block-start: var(--space-md);
    padding-block-start: var(--space-md);
    border-block-start: 1px solid var(--color-border-light);
  }
  
  .signup-item {
    padding: var(--space-sm) 0;
    border-block-end: 1px solid var(--color-border-light);
  }
  
  .signup-item:last-child {
    border-block-end: none;
  }
  
  .signup-name {
    font-weight: 600;
  }
  
  .signup-email {
    color: var(--text-secondary);
    font-size: 0.75rem;
  }
  
  .form-buttons {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-block-start: var(--space-lg);
    gap: var(--space-md);
  }
  
  .form-buttons .btn {
    flex: 1;
    text-align: center;
  }
  
  .form-buttons .btn-success {
    flex: 1.5;
  }
  
  .messages {
    margin-block-end: var(--space-lg);
  }
  
  .message {
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--border-radius-sm);
    margin-block-end: var(--space-sm);
  }
  
  .message.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
  }
  
  .message.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
  }
}

@layer utilities {
  .flex {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
  }
  
  .flex-to-row {
    flex-direction: column;
  }
  
  @media (min-width: 768px) {
    .flex-to-row {
      flex-direction: row;
    }
  }
  
  .text-center {
    text-align: center;
  }
  
  .mb-0 {
    margin-block-end: 0;
  }
  
  .mt-lg {
    margin-block-start: var(--space-lg);
  }
  
  .helper-text {
    margin-block-start: var(--space-xl);
    padding-block-start: var(--space-lg);
    border-block-start: 1px solid var(--color-border-light);
  }
  
  /* Home page specific styles */
  .page-header {
    text-align: center;
    margin-block-end: var(--space-xl);
  }
  
  .subtitle {
    color: var(--text-color);
    font-size: 1.1rem;
    margin-block-start: var(--space-sm);
    font-weight: 500;
  }
  
  .header-top {
    display: flex;
    justify-content: flex-start;
    margin-block-end: var(--space-md);
  }
  
  .nav-back {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    font-weight: 500;
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--border-radius-sm);
    transition: all 0.2s ease;
    font-size: 0.9rem;
  }
  
  .nav-back:hover {
    color: white;
    background: rgba(255, 255, 255, 0.1);
  }
  
  /* Removed the ::before pseudo-element to avoid duplicate arrows */
  
  .info-section {
    margin-block-end: var(--space-xl);
  }
  
  .features-section {
    margin-block-end: var(--space-xl);
  }
  
  .features-grid {
    display: grid;
    gap: var(--space-lg);
    margin-block-start: var(--space-lg);
  }
  
  @media (min-width: 768px) {
    .features-grid {
      grid-template-columns: repeat(2, 1fr);
    }
  }
  
  .feature-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border-light);
    border-radius: var(--border-radius-md);
    padding: var(--space-lg);
    transition: border-color 0.2s ease;
  }
  
  .feature-card:hover {
    border-color: var(--color-primary);
  }
  
  .feature-card h3 {
    color: var(--color-primary);
    margin-block-end: var(--space-sm);
    font-size: 1.1rem;
  }
  
  .feature-card p {
    color: var(--text-secondary);
    margin: 0;
    font-size: 0.9rem;
    line-height: 1.5;
  }
  
  .cta-section {
    text-align: center;
    margin-block-end: var(--space-xl);
  }
  
  .cta-buttons {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    margin-block-start: var(--space-lg);
    flex-wrap: wrap;
  }
  
  .btn {
    display: inline-block;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--border-radius-sm);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s ease;
    border: 2px solid transparent;
  }
  
  .btn-primary {
    background: var(--color-primary);
    color: var(--color-surface);
  }
  
  .btn-primary:hover {
    background: var(--color-primary-dark);
    color: var(--color-surface);
  }
  
  .btn-secondary {
    background: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
  }
  
  .btn-secondary:hover {
    background: var(--color-primary);
    color: var(--color-surface);
  }
  
  /* Credit Hours Styling */
  .credit-hours-summary {
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    border: 1px solid #90caf9;
    border-radius: var(--border-radius-sm);
    padding: var(--space-md);
    margin-block-start: var(--space-md);
    text-align: center;
    font-size: 1.1rem;
    color: #1565c0;
  }
  
  .signup-benefit {
    background: linear-gradient(135deg, #e8f5e8 0%, #c8e6c9 100%);
    border: 1px solid #a5d6a7;
    border-radius: var(--border-radius-sm);
    padding: var(--space-md);
    margin-block-end: var(--space-md);
    text-align: center;
    color: #2e7d32;
    font-size: 1.1rem;
  }
  
  .signup-benefit strong {
    color: #1b5e20;
  }
  
  /* Form Summary Styling */
  .slots-summary {
    margin-block-start: var(--space-lg);
  }
  
  .slot-summary-card {
    background: var(--highlight-high);
    border: 1px solid var(--color-border-light);
    border-radius: var(--border-radius);
    padding: var(--space-lg);
    margin-block-end: var(--space-md);
  }
  
  .slot-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-block-end: var(--space-md);
    padding-block-end: var(--space-sm);
    border-bottom: 1px solid var(--color-border-light);
  }
  
  .slot-header h4 {
    margin: 0;
    color: var(--color-primary);
  }
  
  .slot-date {
    color: var(--text-secondary);
    font-size: 0.9rem;
  }
  
  .signups-list {
    margin-block-start: var(--space-md);
    padding-block-start: var(--space-md);
    border-top: 1px solid var(--color-border-light);
  }
  
  .signups-list h5 {
    margin: 0 0 var(--space-sm) 0;
    color: var(--text-color);
    font-size: 1rem;
  }
  
  .signup-summary-item {
    display: grid;
    grid-template-columns: 2fr 2fr 1fr 1fr;
    gap: var(--space-sm);
    padding: var(--space-sm);
    background: white;
    border-radius: var(--border-radius-sm);
    margin-block-end: var(--space-xs);
    font-size: 0.9rem;
    align-items: center;
  }
  
  .signup-summary-item .signup-name {
    font-weight: 600;
    color: var(--text-color);
  }
  
  .signup-summary-item .signup-email {
    color: var(--text-secondary);
  }
  
  .signup-summary-item .signup-date {
    color: var(--text-secondary);
    font-size: 0.8rem;
  }
  
  .signup-summary-item .signup-credits {
    background: var(--color-primary);
    color: white;
    padding: 0.2rem 0.5rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.8rem;
    font-weight: 600;
    text-align: center;
  }
  
  .no-signups {
    color: var(--text-secondary);
    font-style: italic;
    text-align: center;
    padding: var(--space-md);
  }
  
  @media (max-width: 768px) {
    .signup-summary-item {
      grid-template-columns: 1fr;
      gap: var(--space-xs);
      text-align: center;
    }
    
    .slot-header {
      flex-direction: column;
      align-items: flex-start;
      gap: var(--space-xs);
    }
  }
}