/* General Styles */
body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  margin: 0;
  padding: 0;
  background-color: #f5f5f5;
  color: #333;
}

* {
  box-sizing: border-box;
}

header {
  background-color: #2c3e50;
  color: white;
  padding: 1rem;
  text-align: center;
}

header nav ul {
  list-style: none;
  padding: 0;
  display: flex;
  justify-content: center;
  gap: 1rem;
}

header nav a {
  color: white;
  text-decoration: none;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  transition: background-color 0.3s;
}

header nav a:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

.demo-section {
  margin-bottom: 60px;
  padding-top: 20px;
}

footer {
  background-color: #2c3e50;
  color: white;
  text-align: center;
  padding: 1rem;
  margin-top: 2rem;
}

h1, h2 {
  text-align: center;
}

.container {
  background-color: white;
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 30px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

code {
  background-color: #f0f0f0;
  padding: 2px 4px;
  border-radius: 4px;
  font-family: monospace;
}

/* Control panels */
.control-panel {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
  margin-bottom: 20px;
  padding: 15px;
  background-color: #ecf0f1;
  border-radius: 4px;
}

.control-section {
  flex: 1 1 200px;
}

.control-section h3 {
  margin-top: 0;
  font-size: 1rem;
}

label {
  display: block;
  margin-bottom: 5px;
}

select, button, input {
  padding: 8px 12px;
  border-radius: 4px;
  border: 1px solid #bdc3c7;
  background-color: white;
  font-family: inherit;
  cursor: pointer;
}

button {
  background-color: #3498db;
  color: white;
  border: none;
  transition: background-color 0.3s;
}

button:hover {
  background-color: #2980b9;
}

/* CSS Selectors Demo Styles */
.selector-container {
  background-color: white;
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 20px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* Class selector */
.highlight {
  background-color: #ffeb3b;
  transition: background-color 0.3s;
}

.highlight:hover {
  background-color: #ffc107;
}

/* ID selector */
#special-item {
  font-weight: bold;
  border-left: 4px solid #2196f3;
  padding-left: 10px;
}

/* Attribute selector */
[data-type="important"] {
  color: #e91e63;
}

[data-type="info"] {
  color: #2196f3;
}

/* Pseudo-classes */
.interactive-item {
  padding: 10px;
  margin: 5px 0;
  border-radius: 4px;
  transition: all 0.3s;
  cursor: pointer;
}

.interactive-item:hover {
  background-color: #4caf50;
  color: white;
  transform: translateX(10px);
}

.interactive-item:active {
  background-color: #388e3c;
}

/* Pseudo-elements */
.demo-text::first-letter {
  font-size: 1.5em;
  font-weight: bold;
  color: #9c27b0;
}

.demo-text::after {
  content: " 🔍";
}

/* Interactive demo section */
.interactive-demo {
  background-color: #f1f8e9;
  padding: 15px;
  border-radius: 8px;
  margin-top: 20px;
}

.color-change:hover {
  background-color: #bbdefb;
}

#selector-display {
  font-family: monospace;
  background-color: #263238;
  color: #fff;
  padding: 10px;
  border-radius: 4px;
  margin-top: 10px;
}

/* Navbar Flexbox */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #2c3e50;
  color: white;
  border-radius: 4px;
  padding: 0 20px;
  height: 60px;
}

.logo {
  font-weight: bold;
  font-size: 1.5rem;
}

.nav-links {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links li {
  padding: 0 15px;
}

.nav-links a {
  color: white;
  text-decoration: none;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: #3498db;
}

.menu-toggle {
  display: none;
  cursor: pointer;
}

/* Cards using Flexbox */
.card-container {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: space-between;
  margin-top: 20px;
}

.card {
  flex: 1 1 calc(33.333% - 20px);
  min-width: 250px;
  background-color: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.card-image {
  height: 180px;
  background-color: #3498db;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.2rem;
}

.card-content {
  padding: 20px;
}

.card h3 {
  margin-top: 0;
  color: #2c3e50;
}

/* Mobile styles */
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 60px;
    left: 0;
    width: 100%;
    background-color: #2c3e50;
    padding: 10px 0;
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links li {
    padding: 10px 20px;
  }

  .card {
    flex: 1 1 100%;
  }
}

/* For the demo only - to simulate mobile view */
.mobile-simulation .navbar {
  position: relative;
}

.mobile-simulation .menu-toggle {
  display: block;
}

.mobile-simulation .nav-links {
  display: none;
  flex-direction: column;
  position: absolute;
  top: 60px;
  left: 0;
  width: 100%;
  background-color: #2c3e50;
  padding: 10px 0;
  z-index: 100;
}

.mobile-simulation .nav-links.active {
  display: flex;
}

.mobile-simulation .nav-links li {
  padding: 10px 20px;
}

.mobile-simulation .card {
  flex: 1 1 100%;
}

/* CSS Grid Styles */
.grid-container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 100px);
  gap: 10px;
  margin-top: 20px;
}

.grid-item {
  background-color: #3498db;
  color: white;
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: bold;
  border-radius: 4px;
  transition: background-color 0.3s;
}

.grid-item:hover {
  background-color: #2980b9;
}

/* Grid Gallery */
.gallery-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 15px;
  margin-top: 20px;
}

.gallery-item {
  height: 200px;
  background-color: #3498db;
  color: white;
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: bold;
  border-radius: 4px;
  overflow: hidden;
  transition: transform 0.3s;
}

.gallery-item:hover {
  transform: scale(1.05);
}

/* Grid lines for visualization */
.grid-lines {
  position: relative;
}

.grid-lines::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-size: 33.33% 33.33%;
  pointer-events: none;
  z-index: 1;
  opacity: 0.2;
  transition: opacity 0.3s;
}

.grid-lines:hover::before {
  opacity: 0.4;
}

/* Featured items for gallery */
.featured-wide {
  grid-column: span 2;
}

.featured-tall {
  grid-row: span 2;
}

.featured-large {
  grid-column: span 2;
  grid-row: span 2;
}