/* Main Variables */
:root {
  --primary-color: #0056b3;
  --primary-dark: #004494;
  --primary-light: #3a7cc2;
  --secondary-color: #28a745;
  --secondary-dark: #218838;
  --secondary-light: #48c76a;
  --accent-color: #fd7e14;
  --accent-dark: #e56c07;
  --accent-light: #ff9642;
  --dark-color: #343a40;
  --light-color: #f8f9fa;
  --gray-color: #6c757d;
  --gray-light: #e9ecef;
  --gray-dark: #495057;
  --success-color: #28a745;
  --info-color: #17a2b8;
  --warning-color: #ffc107;
  --danger-color: #dc3545;
  --font-main: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-heading: 'Poppins', 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-code: 'Source Code Pro', Menlo, Monaco, Consolas, 'Courier New', monospace;
  --transition-speed: 0.3s;
  --border-radius: 4px;
  --box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-main);
  line-height: 1.6;
  color: var(--dark-color);
  background-color: var(--light-color);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color var(--transition-speed);
}

a:hover {
  color: var(--primary-dark);
  text-decoration: underline;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  margin-bottom: 1rem;
  font-weight: 600;
  line-height: 1.2;
  color: var(--dark-color);
}

h1 {
  font-size: 2.5rem;
  margin-top: 0;
  color: var(--primary-dark);
  border-bottom: 2px solid var(--primary-light);
  padding-bottom: 0.5rem;
}

h2 {
  font-size: 2rem;
  margin-top: 2rem;
  color: var(--primary-color);
  border-bottom: 1px solid var(--gray-light);
  padding-bottom: 0.3rem;
}

h3 {
  font-size: 1.5rem;
  margin-top: 1.5rem;
  color: var(--dark-color);
}

h4 {
  font-size: 1.25rem;
  margin-top: 1.25rem;
  color: var(--gray-dark);
}

p {
  margin-bottom: 1rem;
}

code {
  font-family: var(--font-code);
  background-color: var(--gray-light);
  padding: 0.2rem 0.4rem;
  border-radius: var(--border-radius);
  font-size: 0.9em;
  color: var(--dark-color);
}

pre {
  background-color: var(--dark-color);
  color: var(--light-color);
  padding: 1rem;
  border-radius: var(--border-radius);
  overflow-x: auto;
  margin-bottom: 1.5rem;
}

pre code {
  background-color: transparent;
  color: inherit;
  padding: 0;
}

ul, ol {
  margin-bottom: 1rem;
  padding-left: 2rem;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1.5rem 0;
  border-radius: var(--border-radius);
}

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

.main-content {
  display: flex;
  flex: 1;
}

.content-area {
  flex: 1;
  padding: 2rem;
  overflow-y: auto;
}

/* Header */
.header {
  background-color: var(--primary-color);
  color: white;
  padding: 1rem 0;
  box-shadow: var(--box-shadow);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: white;
  display: flex;
  align-items: center;
}

.logo img {
  height: 40px;
  margin-right: 0.5rem;
  margin: 0;
}

.logo a {
  color: white;
  text-decoration: none;
}

.header-nav {
  display: flex;
}

.header-nav a {
  color: white;
  margin-left: 1.5rem;
  text-decoration: none;
  transition: opacity var(--transition-speed);
}

.header-nav a:hover {
  opacity: 0.8;
}

/* Sidebar */
.sidebar {
  width: 280px;
  background-color: var(--gray-light);
  padding: 1.5rem 0;
  overflow-y: auto;
  border-right: 1px solid var(--gray-light);
  height: calc(100vh - 64px);
  position: sticky;
  top: 64px;
}

.sidebar-nav {
  list-style: none;
  padding: 0;
}

.sidebar-nav-item {
  margin-bottom: 0.5rem;
}

.sidebar-nav-link {
  display: block;
  padding: 0.5rem 1.5rem;
  color: var(--dark-color);
  text-decoration: none;
  transition: background-color var(--transition-speed);
  border-left: 3px solid transparent;
}

.sidebar-nav-link:hover {
  background-color: rgba(0, 0, 0, 0.05);
  text-decoration: none;
}

.sidebar-nav-link.active {
  background-color: rgba(0, 0, 0, 0.05);
  border-left-color: var(--primary-color);
  color: var(--primary-color);
  font-weight: 500;
}

.sidebar-section {
  margin-bottom: 1.5rem;
}

.sidebar-section-title {
  font-size: 0.9rem;
  text-transform: uppercase;
  color: var(--gray-color);
  padding: 0.5rem 1.5rem;
  margin-bottom: 0.5rem;
  font-weight: 700;
}

.sidebar-nav-subitem {
  margin-left: 1rem;
}

.sidebar-nav-sublink {
  display: block;
  padding: 0.4rem 1.5rem 0.4rem 2.5rem;
  color: var(--gray-dark);
  text-decoration: none;
  transition: background-color var(--transition-speed);
  font-size: 0.9rem;
  border-left: 3px solid transparent;
}

.sidebar-nav-sublink:hover {
  background-color: rgba(0, 0, 0, 0.05);
  text-decoration: none;
}

.sidebar-nav-sublink.active {
  background-color: rgba(0, 0, 0, 0.05);
  border-left-color: var(--primary-color);
  color: var(--primary-color);
  font-weight: 500;
}

/* Mobile menu toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: white;
  font-size: 1.5rem;
  cursor: pointer;
}

/* Footer */
.footer {
  background-color: var(--dark-color);
  color: white;
  padding: 2rem 0;
  margin-top: auto;
}

.footer-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-links {
  display: flex;
}

.footer-links a {
  color: white;
  margin-left: 1.5rem;
  text-decoration: none;
  transition: opacity var(--transition-speed);
}

.footer-links a:hover {
  opacity: 0.8;
  text-decoration: underline;
}

/* Component Styles */
.section-intro {
  background-color: var(--gray-light);
  padding: 1.5rem;
  border-radius: var(--border-radius);
  margin-bottom: 2rem;
  border-left: 4px solid var(--primary-color);
}

.component-section {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--gray-light);
}

.process-steps {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.process-step {
  display: flex;
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  overflow: hidden;
  width: calc(50% - 0.75rem);
}

.step-number {
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--primary-color);
  color: white;
  font-weight: bold;
  font-size: 1.5rem;
  width: 60px;
  padding: 1rem;
}

.step-content {
  padding: 1rem;
  flex: 1;
}

.step-content h4 {
  margin-top: 0;
  color: var(--primary-dark);
}

.feature-item {
  display: flex;
  margin-bottom: 1.5rem;
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  overflow: hidden;
}

.feature-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--primary-light);
  color: white;
  font-size: 1.5rem;
  width: 60px;
  padding: 1rem;
}

.feature-content {
  padding: 1rem;
  flex: 1;
}

.feature-content h4 {
  margin-top: 0;
  color: var(--primary-dark);
}

.integration-grid, .security-grid, .table-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.integration-item, .security-item, .table-item {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
}

.integration-item h4, .security-item h4, .table-item h4 {
  margin-top: 0;
  color: var(--primary-dark);
  border-bottom: 1px solid var(--gray-light);
  padding-bottom: 0.5rem;
  margin-bottom: 0.5rem;
}

.security-icon {
  color: var(--primary-color);
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.conclusion-section {
  background-color: var(--gray-light);
  padding: 1.5rem;
  border-radius: var(--border-radius);
  margin-top: 2rem;
  border-left: 4px solid var(--secondary-color);
}

/* ERD Specific Styles */
.erd-container {
  margin: 2rem 0;
  text-align: center;
}

.erd-image {
  max-width: 100%;
  overflow-x: auto;
  background-color: white;
  padding: 1rem;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
}

#erd-placeholder {
  height: 400px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--gray-light);
  border-radius: var(--border-radius);
}

.entities-section {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.entity-group {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
}

.entity-group h3 {
  margin-top: 0;
  color: var(--primary-dark);
  border-bottom: 1px solid var(--gray-light);
  padding-bottom: 0.5rem;
  margin-bottom: 1rem;
}

.entity-item {
  margin-bottom: 1rem;
}

.entity-item h4 {
  margin-top: 0;
  color: var(--primary-color);
  font-family: var(--font-code);
  font-size: 1.1rem;
}

.relationships-section {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.relationship-group {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
}

.relationship-group h3 {
  margin-top: 0;
  color: var(--primary-dark);
  border-bottom: 1px solid var(--gray-light);
  padding-bottom: 0.5rem;
  margin-bottom: 1rem;
}

.principles-section {
  margin: 1.5rem 0;
}

.principle-item {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.principle-item h3 {
  margin-top: 0;
  color: var(--primary-dark);
  border-bottom: 1px solid var(--gray-light);
  padding-bottom: 0.5rem;
  margin-bottom: 0.5rem;
}

.evolution-section {
  background-color: var(--gray-light);
  padding: 1.5rem;
  border-radius: var(--border-radius);
  margin: 1.5rem 0;
  border-left: 4px solid var(--info-color);
}

/* Responsive Styles */
@media (max-width: 992px) {
  .process-step {
    width: 100%;
  }
  
  .integration-grid, .security-grid, .table-grid, .entities-section, .relationships-section {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  }
}

@media (max-width: 768px) {
  .main-content {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    height: auto;
    position: static;
    border-right: none;
    border-bottom: 1px solid var(--gray-light);
    display: none;
  }
  
  .sidebar.active {
    display: block;
  }
  
  .menu-toggle {
    display: block;
  }
  
  .header-nav {
    display: none;
  }
  
  .header-nav.active {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background-color: var(--primary-color);
    padding: 1rem 0;
    box-shadow: var(--box-shadow);
  }
  
  .header-nav.active a {
    margin: 0;
    padding: 0.5rem 1.5rem;
  }
  
  .footer-container {
    flex-direction: column;
    text-align: center;
  }
  
  .footer-links {
    margin-top: 1rem;
    justify-content: center;
  }
  
  .footer-links a:first-child {
    margin-left: 0;
  }
}

@media (max-width: 576px) {
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.75rem;
  }
  
  h3 {
    font-size: 1.5rem;
  }
  
  .content-area {
    padding: 1.5rem 1rem;
  }
  
  .feature-item, .process-step {
    flex-direction: column;
  }
  
  .feature-icon, .step-number {
    width: 100%;
    padding: 0.5rem;
  }
  
  .integration-grid, .security-grid, .table-grid, .entities-section, .relationships-section {
    grid-template-columns: 1fr;
  }
}