@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Playfair+Display:ital,wght@0,600;0,700;1,400&display=swap');

:root {
  --font-serif: 'Playfair Display', Georgia, serif;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  
  /* Modern Harmonious Color Palette */
  --bg-primary: #f8fafc;
  --bg-card: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  
  --color-primary: #4f46e5; /* Indigo */
  --color-primary-hover: #4338ca;
  --color-accent: #059669; /* Emerald */
  --color-border: #e2e8f0;
  --color-ring: rgba(79, 70, 229, 0.1);
  
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  
  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  padding: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header & Navigation */
header {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--color-border);
  padding: 1.25rem 2rem;
  position: sticky;
  top: 0;
  z-index: 10;
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(8px);
  background-color: rgba(255, 255, 255, 0.9);
}

header nav {
  max-width: 1000px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

header a.logo {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--color-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  transition: opacity 0.2s;
}

header a.logo:hover {
  opacity: 0.85;
}

.header-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.header-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.925rem;
  font-weight: 500;
  transition: color 0.2s, transform 0.2s;
}

.header-links a:hover {
  color: var(--color-primary);
  transform: translateY(-1px);
}

.header-links a.cta-btn {
  background-color: var(--color-primary);
  color: white;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
}

.header-links a.cta-btn:hover {
  background-color: var(--color-primary-hover);
  color: white;
}

/* Main Container */
main {
  max-width: 900px;
  margin: 3rem auto;
  padding: 0 1.5rem;
  width: 100%;
  flex-grow: 1;
}

/* Typography */
h1 {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
  margin-bottom: 1.5rem;
  border-bottom: 2px solid var(--color-border);
  padding-bottom: 0.75rem;
}

h2 {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: 2.5rem;
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1.25rem;
  color: var(--text-secondary);
  font-size: 1.05rem;
}

p strong {
  color: var(--text-primary);
}

/* Metadata & Freshness Banner */
.metadata-banner {
  display: flex;
  gap: 1.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
  flex-wrap: wrap;
  align-items: center;
  border-left: 3px solid var(--color-primary);
  padding-left: 1rem;
}

.metadata-banner span {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

/* Lists */
ul, ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
  color: var(--text-secondary);
}

li {
  margin-bottom: 0.5rem;
}

/* Informative Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  font-size: 0.95rem;
  background-color: var(--bg-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
}

th, td {
  padding: 0.875rem 1.25rem;
  text-align: left;
}

th {
  background-color: #f1f5f9;
  font-weight: 600;
  color: var(--text-primary);
  border-bottom: 2px solid var(--color-border);
}

tr:not(:last-child) {
  border-bottom: 1px solid var(--color-border);
}

tr:hover {
  background-color: #f8fafc;
}

/* Definition Callout Box */
.definition-box {
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.03) 0%, rgba(5, 150, 105, 0.03) 100%);
  border-left: 4px solid var(--color-accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}

.definition-box h4 {
  font-size: 0.9rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-accent);
  margin-bottom: 0.35rem;
}

.definition-box p {
  margin: 0;
  font-style: italic;
  font-size: 1.025rem;
  color: var(--text-secondary);
}

/* Interactive Accordion for FAQs */
.faq-section {
  margin-top: 3rem;
  border-top: 1px solid var(--color-border);
  padding-top: 2rem;
}

.faq-title {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  margin-bottom: 1.5rem;
}

details {
  background-color: var(--bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: 0.75rem;
  padding: 1rem;
  transition: box-shadow 0.2s, border-color 0.2s;
  box-shadow: var(--shadow-sm);
}

details[open] {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

summary {
  font-weight: 600;
  font-size: 1.05rem;
  cursor: pointer;
  outline: none;
  user-select: none;
  list-style: none;
  position: relative;
  padding-right: 2rem;
  color: var(--text-primary);
}

summary::-webkit-details-marker {
  display: none;
}

summary::after {
  content: '+';
  position: absolute;
  right: 0.5rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform 0.2s;
}

details[open] summary::after {
  content: '−';
  color: var(--color-primary);
}

details p {
  margin-top: 0.75rem;
  margin-bottom: 0;
  font-size: 0.975rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--color-border);
  padding-top: 0.75rem;
}

/* Call to Action Section */
.cta-box {
  background-color: var(--bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2.25rem;
  margin: 3rem 0;
  text-align: center;
  box-shadow: var(--shadow-md);
}

.cta-box h3 {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
}

.cta-box p {
  max-width: 600px;
  margin: 0 auto 1.5rem;
}

.cta-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.cta-buttons a {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.2s;
}

.cta-buttons a.primary {
  background-color: var(--color-primary);
  color: white;
  box-shadow: var(--shadow-sm);
}

.cta-buttons a.primary:hover {
  background-color: var(--color-primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.cta-buttons a.secondary {
  background-color: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
}

.cta-buttons a.secondary:hover {
  background-color: var(--color-ring);
  transform: translateY(-1px);
}

/* Footer Section */
footer {
  background-color: #0f172a;
  color: #94a3b8;
  padding: 3rem 2rem;
  margin-top: auto;
  border-top: 1px solid #1e293b;
}

.footer-content {
  max-width: 1000px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 2rem;
  font-size: 0.875rem;
}

.footer-logo {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: white;
  text-decoration: none;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.footer-links a {
  color: #94a3b8;
  text-decoration: none;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: white;
}

.footer-copyright {
  width: 100%;
  text-align: center;
  border-top: 1px solid #1e293b;
  padding-top: 1.5rem;
  margin-top: 1.5rem;
  font-size: 0.75rem;
  color: #64748b;
}

/* Responsiveness */
@media (max-width: 768px) {
  header nav {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .header-links {
    width: 100%;
    justify-content: flex-start;
    flex-wrap: wrap;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  .footer-content {
    flex-direction: column;
    align-items: flex-start;
  }
}