:root {
  /* Light mode variables */
  --bg-color: #f8f9fa;
  --text-color: #212529;
  --card-bg: #ffffff;
  --card-border: #e9ecef;
  --header-bg: #4361ee;
  --header-text: #ffffff;
  --code-bg: #f1f3f5;
  --example-bg: #e9ecef;
  --info-box-bg: #e7f5ff;
  --info-box-border: #74c0fc;
  --tip-box-bg: #ebfbee;
  --tip-box-border: #8ce99a;
  --shortcut-bg: #f1f3f5;
  --shortcut-border: #ced4da;
  --kbd-bg: #e9ecef;
  --kbd-border: #ced4da;
  --link-color: #3a0ca3;
  --link-hover: #4361ee;
  --footer-bg: #343a40;
  --footer-text: #f8f9fa;
  --syntax-operator-bg: #e7f5ff;
  --syntax-operator-border: #74c0fc;
}

.dark-mode {
  /* Dark mode variables */
  --bg-color: #212529;
  --text-color: #f8f9fa;
  --card-bg: #343a40;
  --card-border: #495057;
  --header-bg: #3a0ca3;
  --header-text: #ffffff;
  --code-bg: #495057;
  --example-bg: #495057;
  --info-box-bg: #1c3d5d;
  --info-box-border: #3a86ff;
  --tip-box-bg: #1b4332;
  --tip-box-border: #40916c;
  --shortcut-bg: #343a40;
  --shortcut-border: #495057;
  --kbd-bg: #495057;
  --kbd-border: #6c757d;
  --link-color: #4cc9f0;
  --link-hover: #4895ef;
  --footer-bg: #1a1a1a;
  --footer-text: #f8f9fa;
  --syntax-operator-bg: #1c3d5d;
  --syntax-operator-border: #3a86ff;
}

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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--bg-color);
  transition: background-color 0.3s, color 0.3s;
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 15px;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  margin-bottom: 1rem;
  line-height: 1.2;
}

h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 2rem;
  margin-top: 2rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--card-border);
  display: flex;
  align-items: center;
}

h3 {
  font-size: 1.5rem;
  margin-top: 1.5rem;
}

h4 {
  font-size: 1.25rem;
  margin-top: 1.25rem;
}

p {
  margin-bottom: 1rem;
}

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

code {
  font-family: 'Consolas', 'Monaco', monospace;
  background-color: var(--code-bg);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9rem;
}

/* Header */
header {
  background-color: var(--header-bg);
  color: var(--header-text);
  padding: 2rem 0;
  margin-bottom: 2rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

header .container {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.header-content {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.header-icon {
  width: 64px;
  height: 64px;
  object-fit: contain;
}

header h1 {
  margin-bottom: 0.5rem;
}

.subtitle {
  font-size: 1.2rem;
  margin-bottom: 0;
}

/* Section icons */
.section-icon {
  width: 32px;
  height: 32px;
  margin-right: 0.75rem;
  object-fit: contain;
}

/* Theme toggle button */
#theme-toggle {
  display: flex;
  align-items: center;
  background-color: transparent;
  color: var(--header-text);
  border: 2px solid var(--header-text);
  border-radius: 20px;
  padding: 0.5rem 1rem;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.3s;
}

#theme-toggle:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

#theme-toggle i {
  margin-right: 0.5rem;
}

/* Main content */
main {
  padding-bottom: 3rem;
}

section {
  margin-bottom: 3rem;
}

/* Cards */
.card {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

/* Syntax tables */
.syntax-table {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.syntax-row {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.syntax-operator {
  font-weight: bold;
  background-color: var(--syntax-operator-bg);
  border: 1px solid var(--syntax-operator-border);
  padding: 0.5rem;
  border-radius: 4px;
  font-family: 'Consolas', 'Monaco', monospace;
}

.syntax-description {
  flex: 1;
}

.example {
  margin-top: 0.5rem;
  background-color: var(--example-bg);
  padding: 0.5rem;
  border-radius: 4px;
  position: relative;
}

/* Info boxes */
.info-box {
  background-color: var(--info-box-bg);
  border: 1px solid var(--info-box-border);
  border-radius: 8px;
  padding: 1rem;
  margin: 1.5rem 0;
}

.info-box h5 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.info-box ul {
  margin-bottom: 0;
}

/* Example boxes */
.example-box {
  background-color: var(--example-bg);
  padding: 1rem;
  border-radius: 8px;
  margin: 1rem 0;
  font-family: 'Consolas', 'Monaco', monospace;
  position: relative;
}

/* Two-column layout */
.two-column {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

/* Keyboard shortcuts */
.shortcuts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1rem;
}

.shortcut {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  background-color: var(--shortcut-bg);
  border: 1px solid var(--shortcut-border);
  border-radius: 8px;
  padding: 1rem;
}

.keys {
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

kbd {
  background-color: var(--kbd-bg);
  border: 1px solid var(--kbd-border);
  border-radius: 4px;
  padding: 0.2rem 0.5rem;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 0.9rem;
  box-shadow: 0 2px 0 var(--kbd-border);
}

/* Tips and best practices */
.tip-box {
  margin-bottom: 1.5rem;
  background-color: var(--tip-box-bg);
  border: 1px solid var(--tip-box-border);
  border-radius: 8px;
  padding: 1rem;
}

.tip-box h4 {
  display: flex;
  align-items: center;
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.tip-box h4 i {
  margin-right: 0.5rem;
}

/* Complex examples */
.example-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.complex-example {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 1rem;
}

.complex-example h4 {
  margin-top: 0;
  margin-bottom: 0.75rem;
  font-size: 1rem;
}

.code-block {
  background-color: var(--code-bg);
  padding: 0.75rem;
  border-radius: 4px;
  font-family: 'Consolas', 'Monaco', monospace;
  overflow-x: auto;
  position: relative;
}

/* Copy button styles */
.copy-button {
  position: absolute;
  right: 8px;
  top: 8px;
  background: transparent;
  border: none;
  color: var(--text-color);
  cursor: pointer;
  font-size: 0.9rem;
  opacity: 0.7;
  transition: opacity 0.2s;
}

.copy-button:hover {
  opacity: 1;
}

/* Footer */
footer {
  background-color: var(--footer-bg);
  color: var(--footer-text);
  padding: 1.5rem 0;
  text-align: center;
}

/* Responsive design */
@media (min-width: 768px) {
  header .container {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
  
  .header-content {
    margin-bottom: 0;
  }
  
  .syntax-row {
    flex-direction: row;
  }
  
  .syntax-operator {
    width: 150px;
    margin-right: 1rem;
  }
}

@media (max-width: 767px) {
  .two-column {
    grid-template-columns: 1fr;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.75rem;
  }
  
  h3 {
    font-size: 1.5rem;
  }
  
  .header-icon {
    width: 48px;
    height: 48px;
  }
  
  .section-icon {
    width: 24px;
    height: 24px;
  }
}

@media (max-width: 480px) {
  .container {
    width: 95%;
    padding: 0 10px;
  }
  
  h1 {
    font-size: 1.75rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
  
  .card {
    padding: 1rem;
  }
  
  .header-content {
    gap: 0.75rem;
  }
  
  .header-icon {
    width: 40px;
    height: 40px;
  }
}