/* ==========================================================================
   CSS Variables & Theme Definitions
   ========================================================================== */
   :root {
    /* Base Colors */
    --bg-color: #ffffff;
    --text-color: #333333;
    --link-color: #0066cc;
    --link-hover-color: #0052a3;
    --secondary-text: #666666;
    --border-color: #dddddd;
    
    /* Component Backgrounds */
    --input-bg: #ffffff;
    --result-bg: #f5f5f5;
    --card-bg: #ffffff;
    
    /* Buttons */
    --button-bg: #0066cc;
    --button-text: #ffffff;
    --button-hover-bg: #0052a3;
    
    /* Navigation */
    --nav-button-bg: #f8f9fa;
    --nav-button-hover-bg: #e9ecef;
    
    /* Shadows */
    --shadow-color: rgba(0, 0, 0, 0.1);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-default: 0.3s ease;
  }
  
  [data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #e0e0e0;
    --link-color: #66b3ff;
    --link-hover-color: #99ccff;
    --secondary-text: #b0b0b0;
    --border-color: #404040;
    
    --input-bg: #333333;
    --result-bg: #2a2a2a;
    --card-bg: #2d2d2d;
    
    --button-bg: #66b3ff;
    --button-text: #1a1a1a;
    --button-hover-bg: #99ccff;
    
    --nav-button-bg: #2a2a2a;
    --nav-button-hover-bg: #333333;
    
    --shadow-color: rgba(0, 0, 0, 0.3);
  }
  
  /* ==========================================================================
     Global Styles & Resets
     ========================================================================== */
  *,
  *::before,
  *::after {
    box-sizing: border-box;
  }
  
  body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color var(--transition-default), color var(--transition-default);
    min-height: 100vh;
  }
  
  /* Container for Main Content */
  .container {
    width: 100%;
    max-width: 50rem; /* 800px */
    margin: 0 auto;
    padding: 0.625rem; /* 10px */
  }
  
  .container > * {
    margin: 0 0 1.25rem 0; /* 20px bottom margin */
  }
  
  .container > *:last-child {
    margin-bottom: 0;
  }
  
  /* ==========================================================================
     Navigation
     ========================================================================== */
  
  /* Main Navigation */
  .main-nav {
    display: flex;
    flex-direction: column;
    gap: 1rem; /* 16px */
    margin: 2rem 0; /* 32px top & bottom */
  }
  
  .nav-button {
    display: flex;
    align-items: center;
    gap: 0.75rem; /* 12px */
    padding: 1rem 1.5rem; /* 16px 24px */
    background-color: var(--nav-button-bg);
    color: var(--text-color);
    text-decoration: none;
    border-radius: 0.75rem; /* 12px */
    border: 1px solid var(--border-color);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast),
                background-color var(--transition-fast);
    font-size: 1.125rem; /* 18px */
  }
  
  .nav-button:hover {
    background-color: var(--nav-button-hover-bg);
    transform: translateY(-0.125rem); /* -2px */
    box-shadow: 0 0.25rem 0.5rem rgba(0, 0, 0, 0.1);
  }
  
  .nav-icon {
    font-size: 1.5rem; /* 24px */
  }
  
  /* Regular Navigation Links */
  nav {
    margin: 1.25rem 0; /* 20px */
    display: flex;
    flex-direction: column;
    gap: 0.75rem; /* 12px */
  }
  
  nav a {
    text-decoration: none;
    color: var(--link-color);
    padding: 0.5rem 0; /* 8px top & bottom */
  }
  
  /* ==========================================================================
     Typography
     ========================================================================== */
  h1 {
    font-size: 1.75rem;
    margin: 0.75rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem; /* 8px */
  }
  
  h1 i {
    color: var(--link-color);
  }
  
  h2 {
    color: var(--text-color);
    font-size: 1.25rem; /* 20px */
    margin-top: 1.5rem; /* 24px */
  }
  
  /* Back Link Button */
  .back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem; /* 8px */
    padding: 0.5rem 1rem; /* 8px 16px */
    margin-bottom: 0.5rem;
    background: var(--card-bg);
    border-radius: 1.25rem; /* 20px */
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    border: 1px solid var(--border-color);
    font-size: 0.9rem;
    transition: transform var(--transition-default), border-color var(--transition-fast),
                box-shadow var(--transition-fast);
  }
  
  .back-link:hover {
    background: var(--nav-button-hover-bg);
    transform: translateX(-0.375rem); /* -6px */
    border-color: var(--link-color);
    box-shadow: 0 0.25rem 0.5rem var(--shadow-color);
  }
  
  .back-link i {
    color: var(--link-color);
    font-size: 1.125rem; /* 18px */
    transition: transform var(--transition-default);
  }
  
  .back-link:hover i {
    transform: translateX(-0.25rem); /* -4px */
  }
  
  /* ==========================================================================
     Calculator Component
     ========================================================================== */
  .calculator {
    background: var(--card-bg);
    width: 100%;
    margin: 0 auto;
    padding: 1rem;
  }
  
  .calculator h1 {
    text-align: center;
    margin-bottom: 1rem;
    font-size: 1.5rem;
  }
  
  .calculator .input-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 0.5rem;
  }
  
  .calculator label {
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
  }
  
  .calculator input {
    width: 100%;
    padding: 0.5rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 0.5rem; /* 8px */
    transition: border-color var(--transition-fast);
    background: var(--input-bg);
    color: var(--text-color);
    text-align: center;
  }
  
  .calculator input:focus {
    outline: none;
    border-color: var(--link-color);
  }
  
  .calculator .results {
    background: var(--result-bg);
    padding: 0.75rem;
    border-radius: 0.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
  }
  
  .calculator .result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0.75rem;
    background: var(--card-bg);
    border-radius: 0.375rem; /* 6px */
    box-shadow: 0 0.0625rem 0.1875rem var(--shadow-color);
  }
  
  .calculator .result-item span {
    font-size: 0.9rem;
    color: var(--text-color);
  }
  
  .calculator .result-item span:last-child {
    font-weight: 600;
  }
  
  #result {
    margin-top: 1.25rem;
    padding: 1rem;
    background-color: var(--result-bg);
    border-radius: 0.5rem;
    display: none;
  }
  
  /* ==========================================================================
     Recipe & Form Components
     ========================================================================== */
  
  /* Recipe Sections & Lists */
  .recipe-section {
    margin: 0;
    border-radius: 0.5rem;
  }
  
  .recipe-section.compact {
    margin-bottom: 0;
  }
  
  .recipe-section h2 {
    font-size: 1.2rem;
    margin-bottom: 0.75rem;
  }
  
  .recipe-list {
    list-style: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
  }
  
  .recipe-list a {
    text-decoration: none;
    color: var(--link-color);
    padding: 0.5rem;
    display: block;
    background-color: var(--result-bg);
    border-radius: 0.5rem;
  }
  
  ul,
  ol {
    padding-left: 1.25rem; /* 20px */
  }
  
  /* Form Elements */
  .input-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
  }
  
  .input-group label {
    font-size: 0.9rem;
    font-weight: 500;
    margin: 0;
  }
  
  .input-group input {
    padding: 0.375rem; /* 6px */
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 0.375rem; /* 6px */
    text-align: center;
    background: var(--input-bg);
    color: var(--text-color);
  }
  
  /* Buttons */
  button {
    background-color: var(--button-bg);
    color: var(--button-text);
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    cursor: pointer;
    margin-top: 1rem;
    width: 100%;
    max-width: 18.75rem; /* 300px */
    transition: opacity var(--transition-fast);
  }
  
  button:hover {
    opacity: 0.9;
  }
  
  /* Recipe Grid Layout */
  .recipe-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(17.5rem, 1fr)); /* 280px */
    gap: 1.5rem; /* 24px */
    padding: 1.25rem 0;
  }
  
  .recipe-card {
    background: var(--card-bg);
    border-radius: 1rem; /* 16px */
    padding: 1.5rem;
    text-decoration: none;
    color: var(--text-color);
    transition: transform var(--transition-default), box-shadow var(--transition-default),
                border-color var(--transition-fast);
    border: 0.125rem solid var(--border-color); /* 2px */
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    box-shadow: 0 0.25rem 0.375rem var(--shadow-color);
  }
  
  .recipe-card:hover {
    transform: translateY(-0.5rem); /* -8px */
    box-shadow: 0 0.5rem 0.9375rem var(--shadow-color);
    border-color: var(--link-color);
  }
  
  .recipe-icon {
    font-size: 3rem; /* 48px */
    color: var(--link-color);
    margin-bottom: 1rem;
    background: var(--result-bg);
    width: 6rem; /* 96px */
    height: 6rem; /* 96px */
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform var(--transition-default), color var(--transition-default);
  }
  
  .recipe-card:hover .recipe-icon {
    transform: scale(1.1) rotate(5deg);
    color: var(--link-hover-color);
  }
  
  .recipe-card h2 {
    margin: 0 0 0.75rem 0;
    font-size: 1.375rem; /* 22px */
    color: var(--text-color);
  }
  
  .recipe-card p {
    margin: 0;
    color: var(--secondary-text);
    font-size: 1rem; /* 16px */
    line-height: 1.4;
  }
  
  .recipe-content {
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }
  
  /* Quick Select Buttons */
  .quick-select {
    display: flex;
    gap: 1.25rem; /* 20px */
    flex-wrap: nowrap;
    justify-content: center;
    margin-top: 0.25rem;
  }
  
  .quick-select button {
    padding: 0.375rem 0.75rem; /* 6px 12px */
    border: 1px solid var(--border-color);
    border-radius: 0.25rem; /* 4px */
    background: var(--input-bg);
    color: var(--text-color);
    font-size: 0.9rem;
    cursor: pointer;
    transition: border-color var(--transition-fast);
    min-width: 2.25rem; /* 36px */
  }
  
  .quick-select button:hover {
    border-color: var(--link-color);
  }
  
  .quick-select button.active {
    background: var(--link-color);
    color: var(--button-text);
    border-color: var(--link-color);
  }
  
  /* Ingredients Section */
  .ingredients-section {
    margin-top: 0;
  }
  
  .ingredients-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(8.75rem, 1fr)); /* 140px */
    gap: 0.5rem; /* 8px */
    margin: 0;
    padding: 0;
  }
  
  .ingredient-item {
    background: var(--card-bg);
    padding: 0.5rem 0.75rem; /* 8px 12px */
    border-radius: 0.375rem; /* 6px */
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 0.25rem;
    box-shadow: 0 0.0625rem 0.1875rem var(--shadow-color);
  }
  
  .ingredient-item span {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--link-color);
  }
  
  .ingredient-item div {
    font-size: 0.9rem;
    color: var(--text-color);
  }
  
  /* Ordered Lists */
  ol {
    margin: 0;
    padding-left: 1.5rem;
  }
  
  ol li {
    margin-bottom: 0.5rem;
  }
  
  ol li:last-child {
    margin-bottom: 0;
  }
  
  /* ==========================================================================
     Tablet & Up Media Queries (min-width: 48rem / 768px)
     ========================================================================== */
  @media (min-width: 48rem) {
    body {
      padding: 0.8125rem; /* 13px */
    }
    
    .main-nav {
      flex-direction: row;
      gap: 1.5rem; /* 24px */
    }
    
    .nav-button {
      flex: 1;
      justify-content: center;
    }
    
    nav {
      flex-direction: row;
      gap: 1.5rem;
    }
    
    .recipe-list {
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(15.625rem, 1fr)); /* 250px */
      gap: 1rem; /* 16px */
    }
    
    button {
      width: auto;
    }
    
    .calculator {
      padding: 1rem;
    }
    
    .calculator h1 {
      font-size: 1.75rem;
    }
    
    .calculator label {
      font-size: 1rem;
    }
    
    .calculator input {
      padding: 0.75rem;
      font-size: 1.2rem;
    }
    
    .calculator .results {
      padding: 1rem;
      gap: 0.5rem;
    }
    
    .calculator .result-item {
      padding: 0.75rem;
    }
    
    .calculator .result-item span {
      font-size: 1.1rem;
    }
    
    .recipe-section {
      padding: 1rem;
    }
    
    .recipe-section h2 {
      font-size: 1.4rem;
    }
    
    .input-group {
      gap: 0.75rem;
    }
    
    .input-group label {
      font-size: 1rem;
    }
    
    .quick-select {
      gap: 0.375rem;
    }
    
    .quick-select button {
      padding: 0.5rem 1rem;
    }
    
    .ingredients-grid {
      gap: 0.75rem;
    }
    
    .ingredient-item {
      padding: 0.75rem 1rem;
    }
  }