/* Global Styles */
:root {
  --primary-color: #3498db;
  --secondary-color: #2ecc71;
  --accent-color: #f39c12;
  --background-color: #f5f5f5;
  --text-color: #333333;
  --white: #ffffff;
  --light-gray: #eeeeee;
  --box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

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

body {
  font-family: 'Open Sans', sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--background-color);
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Montserrat', sans-serif;
  margin-top: 1.5rem;
  margin-bottom: 1.5rem;
  color: var(--primary-color);
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  color: #1a6ca4;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
header {
  background-color: var(--white);
  box-shadow: var(--box-shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--primary-color);
}

.logo span {
  color: var(--secondary-color);
}

/* Navigation */
nav ul {
  display: flex;
  list-style: none;
}

nav ul li {
  margin-left: 1.5rem;
}

nav ul li a {
  font-weight: 600;
}

.active {
  color: var(--secondary-color);
}

/* Mobile Navigation */
.hamburger {
  display: none;
  cursor: pointer;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--primary-color), #2980b9);
  color: var(--white);
  padding: 4rem 0;
  text-align: center;
}

.hero h1 {
  font-size: 2.5rem;
  color: var(--white);
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto 2rem;
}

.btn {
  display: inline-block;
  background-color: var(--secondary-color);
  color: var(--white);
  padding: 0.8rem 1.5rem;
  border-radius: 4px;
  font-weight: 600;
  transition: background-color 0.3s ease;
}

.btn:hover {
  background-color: #27ae60;
  color: var(--white);
}

/* Main Content */
main {
  padding: 2rem 0;
}

section {
  margin-bottom: 3rem;
}

.section-title {
  margin-top: 2rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--primary-color);
}

p {
  margin-bottom: 1.2rem;
}

.content-container {
  display: flex;
  gap: 2rem;
}

.sidebar {
  width: 250px;
  background-color: var(--white);
  padding: 1.5rem;
  border-radius: 4px;
  box-shadow: var(--box-shadow);
}

.sidebar h3 {
  margin-bottom: 1rem;
}

.sidebar ul {
  list-style: none;
}

.sidebar ul li {
  margin-bottom: 0.5rem;
}

.main-content {
  flex: 1;
  background-color: var(--white);
  padding: 2rem;
  border-radius: 4px;
  box-shadow: var(--box-shadow);
}

/* Cards */
.cards-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.card {
  background-color: var(--white);
  border-radius: 4px;
  box-shadow: var(--box-shadow);
  overflow: hidden;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  display: flex;
  flex-direction: column;
  height: 450px;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.card-image {
  height: 200px;
  background-color: var(--light-gray);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.card-content {
  padding: 1.5rem;
  flex: 1;
  overflow-y: auto;
}

.card-title {
  font-size: 1.2rem;
  margin-top: 0;
  margin-bottom: 1rem;
}

/* Boxes */
.definition-box, .theorem-box, .example-box, .note-box {
  margin: 1.5rem 0;
  padding: 1.5rem;
  border-radius: 4px;
  background-color: var(--light-gray);
  border-left: 4px solid var(--primary-color);
}

.theorem-box {
  border-left-color: var(--secondary-color);
}

.example-box {
  border-left-color: var(--accent-color);
}

.note-box {
  border-left-color: #e74c3c;
}

/* Interactive Elements */
.interactive-container {
  margin: 2rem 0;
  padding: 1.5rem;
  background-color: var(--light-gray);
  border-radius: 4px;
}

.slider-container {
  margin: 1rem 0;
}

.slider {
  width: 100%;
}

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

.footer-container {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
}

.footer-section {
  flex: 1;
  min-width: 250px;
  margin-bottom: 1.5rem;
}

.footer-section h3 {
  color: var(--white);
  margin-bottom: 1rem;
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: 0.5rem;
}

.footer-section a {
  color: var(--white);
  opacity: 0.8;
}

.footer-section a:hover {
  opacity: 1;
}

.copyright {
  text-align: center;
  padding-top: 1.5rem;
  margin-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Responsive Design */
@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    align-items: flex-start;
  }
  
  nav {
    width: 100%;
    margin-top: 1rem;
  }
  
  nav ul {
    flex-direction: column;
  }
  
  nav ul li {
    margin: 0;
    margin-bottom: 0.5rem;
  }
  
  .hamburger {
    display: block;
    position: absolute;
    top: 1rem;
    right: 1rem;
  }
  
  .content-container {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
  }
  
  .cards-container {
    grid-template-columns: 1fr;
  }
}

.inner-list {
  padding-left: 20px;
}

/* Math Styling */
.math-formula {
  padding: 1rem;
  margin: 1rem 0;
  background-color: var(--light-gray);
  border-radius: 4px;
  overflow-x: auto;
}

/* Code for interactive elements will be added with JavaScript */