/* ============================================
   Healthcare AI  Textbook
   ============================================ */

/* CSS Variables -  Color Scheme */
:root {
  /* Primary Colors - Warm, professional tones */
  --primary: #1a5490;           /* Deep blue - professional, trustworthy */
  --primary-dark: #0d3d6b;      /* Darker blue for hover states */
  --primary-light: #4a7bb5;     /* Lighter blue for accents */
  
  /* Secondary Colors */
  --secondary: #2c5f7d;         /* Muted teal-blue */
  --accent: #d97757;            /* Warm orange/coral for highlights */
  --accent-light: #f4a582;      /* Lighter coral */
  
  /* Text Colors - Readable, warm grays */
  --text-primary: #2d2d2d;      /* Almost black for body text */
  --text-secondary: #5a5a5a;    /* Medium gray for secondary text */
  --text-light: #777;           /* Light gray for captions */
  --text-muted: #999;           /* Very light gray for meta info */
  
  /* Background Colors - Clean, warm whites */
  --bg-primary: #ffffff;        /* Pure white for main content */
  --bg-secondary: #f8f8f6;      /* Warm off-white for sections */
  --bg-tertiary: #f0f0ed;       /* Slightly darker warm gray */
  --bg-code: #f5f5f2;           /* Warm light gray for code */
  
  /* Border Colors */
  --border-light: #e8e8e5;      /* Light warm gray borders */
  --border-medium: #d0d0cc;     /* Medium borders */
  --border-dark: #a0a09a;       /* Dark borders for emphasis */
  
  /* Semantic Colors */
  --success: #5a9367;           /* Muted green */
  --warning: #d97757;           /* Warm orange */
  --error: #c55;                /* Muted red */
  --info: --primary;            /* Use primary blue */
  
  /* Typography - Elegant, readable serif and sans */
  --font-serif: 'Charter', 'Bitstream Charter', 'Georgia', 'Times New Roman', serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Courier New', monospace;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2.5rem;
  --spacing-xxl: 4rem;
  
  /* Layout */
  --content-width: 900px;       /* Optimized for readability */
  --container-width: 1200px;    /* Wide for layout */
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.08);
}

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

html {
  font-size: 18px;  /* Larger base font for readability */
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-serif);
  line-height: 1.7;
  color: var(--text-primary);
  background: var(--bg-primary);
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 600;
  line-height: 1.3;
  color: var(--primary);
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.01em;
}

h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-top: 0;
  line-height: 1.2;
}

h2 {
  font-size: 1.875rem;
  font-weight: 600;
  margin-top: var(--spacing-xxl);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--border-light);
}

h3 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--primary-dark);
}

h4 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--secondary);
}

h5, h6 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

p {
  margin-bottom: var(--spacing-lg);
  font-size: 1rem;
  line-height: 1.8;
}

/* First paragraph drop cap (optional, Waymark-style) */
.chapter-content > p:first-of-type::first-letter {
  font-size: 3.5em;
  line-height: 0.9;
  float: left;
  margin: 0.1em 0.1em 0 0;
  font-weight: 700;
  color: var(--primary);
}

/* Links */
a {
  color: var(--primary);
  text-decoration: none;
  border-bottom: 1px solid var(--primary-light);
  transition: all 0.2s ease;
}

a:hover {
  color: var(--primary-dark);
  border-bottom-color: var(--primary-dark);
}

/* Remove underline from nav links */
nav a {
  border-bottom: none;
}

/* Container */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: var(--spacing-xl);
}

/* Content area - narrower for readability */
.content,
article.chapter-content {
  max-width: var(--content-width);
  margin: 0 auto;
  font-size: 1rem;
  line-height: 1.8;
}

@media (max-width: 768px) {
  .container {
    padding: var(--spacing-lg);
  }
  
  .content,
  article.chapter-content {
    max-width: 100%;
  }
}

/* Navigation - Clean, minimal */
nav {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-light);
  padding: var(--spacing-lg) 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.95);
}

nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-sm) var(--spacing-xl);
}

nav .nav-home {
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--primary);
}

nav a {
  font-family: var(--font-sans);
  color: var(--text-secondary);
  margin: 0 var(--spacing-md);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s;
  letter-spacing: 0.01em;
}

nav a:hover {
  color: var(--primary);
}

.nav-links {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
}

@media (max-width: 768px) {
  nav .container {
    flex-direction: column;
    gap: var(--spacing-md);
  }
  
  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* Page Header */
.page-header {
  margin-bottom: var(--spacing-xxl);
  padding-bottom: var(--spacing-xl);
  border-bottom: 1px solid var(--border-light);
  text-align: left;
}

.chapter-label {
  font-family: var(--font-sans);
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--spacing-sm);
}

.page-title {
  margin-top: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  color: var(--primary-dark);
}

.page-description {
  color: var(--text-secondary);
  font-size: 1.1rem;
  font-style: italic;
  font-family: var(--font-serif);
}

/* Code Blocks - Clean, minimal */
code {
  font-family: var(--font-mono);
  background: var(--bg-code);
  padding: 0.15rem 0.4rem;
  border-radius: 3px;
  font-size: 0.88em;
  color: var(--text-primary);
  border: 1px solid var(--border-light);
}

pre {
  background: var(--bg-code);
  padding: var(--spacing-lg);
  border-radius: 6px;
  overflow-x: auto;
  border-left: 3px solid var(--accent);
  position: relative;
  margin: var(--spacing-xl) 0;
  box-shadow: var(--shadow-sm);
}

pre code {
  background: none;
  padding: 0;
  border-radius: 0;
  border: none;
  display: block;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--text-primary);
}

/* Copy code button */
.copy-code-button {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  padding: 0.35rem 0.7rem;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 4px;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  cursor: pointer;
  opacity: 0;
  transition: all 0.2s;
  letter-spacing: 0.02em;
}

pre:hover .copy-code-button {
  opacity: 0.8;
}

.copy-code-button:hover {
  opacity: 1 !important;
  background: var(--primary-dark);
}

/* Math Styling - Elegant integration */
.MathJax_Display {
  overflow-x: auto;
  overflow-y: hidden;
  max-width: 100%;
  padding: var(--spacing-lg) 0;
  margin: var(--spacing-xl) 0;
}

.MathJax {
  outline: 0;
  font-size: 1.05em !important;
}

code.has-jax {
  font: inherit;
  font-size: 100%;
  background: inherit;
  border: inherit;
  color: inherit;
  padding: 0;
}

div.MathJax_Display {
  text-align: center;
  margin: var(--spacing-xl) 0;
}

/* Tables - Clean, professional */
table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-xl) 0;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  background: var(--bg-primary);
  box-shadow: var(--shadow-sm);
  border-radius: 6px;
  overflow: hidden;
}

th, td {
  padding: var(--spacing-md) var(--spacing-lg);
  text-align: left;
  border-bottom: 1px solid var(--border-light);
}

th {
  background: var(--bg-secondary);
  font-weight: 600;
  color: var(--primary-dark);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

tr:last-child td {
  border-bottom: none;
}

tr:hover {
  background: var(--bg-secondary);
}

/* Lists - Better spacing */
ul, ol {
  margin-left: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
}

li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.7;
}

li::marker {
  color: var(--accent);
}

/* Nested lists */
li > ul,
li > ol {
  margin-top: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

/* Blockquotes - Elegant, Waymark style */
blockquote {
  border-left: 4px solid var(--accent);
  padding-left: var(--spacing-lg);
  margin: var(--spacing-xl) 0;
  color: var(--text-secondary);
  font-style: italic;
  font-size: 1.05rem;
  background: var(--bg-secondary);
  padding: var(--spacing-lg);
  border-radius: 0 6px 6px 0;
}

blockquote p:last-child {
  margin-bottom: 0;
}

/* Pull quotes (for emphasis) */
.pullquote {
  font-size: 1.4rem;
  line-height: 1.5;
  color: var(--primary);
  text-align: center;
  margin: var(--spacing-xxl) 0;
  padding: var(--spacing-xl) var(--spacing-lg);
  border-top: 2px solid var(--accent);
  border-bottom: 2px solid var(--accent);
  font-weight: 500;
}

/* Table of Contents - Sidebar style with scroll and collapse */
.table-of-contents {
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: 6px;
  padding: var(--spacing-lg);
  margin: var(--spacing-xl) 0;
  box-shadow: var(--shadow-sm);
  max-height: 500px;
  overflow-y: auto;
  position: relative;
  z-index: 1;
}

.table-of-contents h2 {
  font-size: 1rem;
  font-weight: 600;
  margin-top: 0;
  margin-bottom: var(--spacing-md);
  border: none;
  padding: 0;
  color: var(--primary-dark);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  cursor: pointer;
  user-select: none;
}

.table-of-contents ul {
  list-style: none;
  margin-left: 0;
}

.table-of-contents li {
  margin-bottom: var(--spacing-sm);
  font-family: var(--font-sans);
  font-size: 0.9rem;
}

.table-of-contents li.h3 {
  margin-left: var(--spacing-lg);
  font-size: 0.85rem;
}

.table-of-contents a {
  color: var(--text-primary);
  text-decoration: none;
  border: none;
  transition: color 0.2s;
}

.table-of-contents a:hover {
  color: var(--primary);
}

/* Chapter Navigation - Subtle, elegant */
.chapter-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-xxl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border-light);
  gap: var(--spacing-lg);
  font-family: var(--font-sans);
}

.chapter-nav a {
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: 6px;
  text-decoration: none;
  color: var(--text-primary);
  transition: all 0.2s;
  font-weight: 500;
  font-size: 0.9rem;
}

.chapter-nav a:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

@media (max-width: 768px) {
  .chapter-nav {
    flex-direction: column;
  }
  
  .chapter-nav a {
    width: 100%;
    text-align: center;
  }
}

/* Alerts/Callouts - Waymark style */
.alert {
  padding: var(--spacing-lg);
  border-radius: 6px;
  margin: var(--spacing-xl) 0;
  border-left: 4px solid;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  box-shadow: var(--shadow-sm);
}

.alert-info {
  background: #f0f7fb;
  border-color: var(--primary);
  color: var(--primary-dark);
}

.alert-warning {
  background: #fef6f2;
  border-color: var(--warning);
  color: #8b4513;
}

.alert-success {
  background: #f2f8f4;
  border-color: var(--success);
  color: #2d5f3a;
}

.alert-error {
  background: #fef2f2;
  border-color: var(--error);
  color: #991b1b;
}

/* Footer - Minimal, elegant */
footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
  margin-top: var(--spacing-xxl);
  padding: var(--spacing-xxl) 0;
  text-align: center;
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
}

footer p {
  margin-bottom: var(--spacing-sm);
  line-height: 1.6;
}

footer a {
  color: var(--text-secondary);
  border-bottom: 1px solid transparent;
}

footer a:hover {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

/* Horizontal Rules */
hr {
  border: none;
  border-top: 1px solid var(--border-light);
  margin: var(--spacing-xxl) 0;
}

/* Images */
img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
  margin: var(--spacing-xl) 0;
  box-shadow: var(--shadow-sm);
}

figure {
  margin: var(--spacing-xl) 0;
}

figcaption {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: var(--text-light);
  text-align: center;
  margin-top: var(--spacing-sm);
  font-style: italic;
}

/* Definition Lists */
dt {
  font-weight: 600;
  color: var(--primary-dark);
  margin-top: var(--spacing-md);
}

dd {
  margin-left: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

/* Footnotes */
.footnotes {
  margin-top: var(--spacing-xxl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border-light);
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.footnotes ol {
  margin-left: var(--spacing-lg);
}

/* Print Styles */
@media print {
  nav, footer, .chapter-nav, .copy-code-button {
    display: none;
  }
  
  body {
    font-size: 11pt;
    line-height: 1.5;
    color: black;
  }
  
  h1, h2, h3 {
    page-break-after: avoid;
    color: black;
  }
  
  pre, blockquote {
    page-break-inside: avoid;
    border: 1px solid #999;
  }
  
  a {
    text-decoration: underline;
    color: black;
  }
  
  .MathJax_Display {
    page-break-inside: avoid;
  }
  
  /* Show URLs for links */
  a[href^="http"]:after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
  }
}

/* Responsive Typography */
@media (max-width: 768px) {
  html {
    font-size: 16px;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.625rem;
  }
  
  h3 {
    font-size: 1.375rem;
  }
  
  .MathJax_Display {
    font-size: 90%;
  }
  
  pre {
    font-size: 0.85rem;
    padding: var(--spacing-md);
  }
  
  .pullquote {
    font-size: 1.2rem;
  }
  
  .table-of-contents {
    max-height: 300px;
  }
}

/* Accessibility */
:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary);
  color: white;
  padding: 8px;
  text-decoration: none;
  z-index: 9999;
  font-family: var(--font-sans);
}

.skip-link:focus {
  top: 0;
}

/* Selection Color */
::selection {
  background: var(--accent-light);
  color: white;
}

::-moz-selection {
  background: var(--accent-light);
  color: white;
}

/* Loading States */
.MathJax_Preview {
  color: var(--text-muted);
  font-style: italic;
  font-size: 0.9em;
}

.MathJax_Error {
  color: var(--error);
  font-style: italic;
}

/* Smooth Scrolling for Internal Links */
html {
  scroll-padding-top: 80px; /* Account for fixed nav */
}

/* Utility Classes */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-muted { color: var(--text-muted); }
.text-small { font-size: 0.875rem; }
.font-sans { font-family: var(--font-sans); }
.font-serif { font-family: var(--font-serif); }