:root {
  --primary: #4CAF50;
  --primary-dark: #388E3C;
  --secondary: #2196F3;
  --text: #333;
  --bg: #fff;
  --gray: #f5f5f5;
}

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

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  color: var(--text);
  line-height: 1.6;
}

/* Header & Navigation */
.nav-main {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--bg);
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 100;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--primary);
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--primary);
}

.nav-auth {
  display: flex;
  gap: 1rem;
  align-items: center;
}

button {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s;
}

#loginBtn {
  background: transparent;
  color: var(--text);
}

#signupBtn {
  background: var(--primary);
  color: white;
}

#signupBtn:hover {
  background: var(--primary-dark);
}

.cart-btn {
  background: transparent;
  position: relative;
}

#cartCount {
  position: absolute;
  top: -5px;
  right: -5px;
  background: var(--primary);
  color: white;
  border-radius: 50%;
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
}

/* Hero Section */
.hero {
  margin-top: 80px;
  text-align: center;
  padding: 4rem 2rem;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
}

.cta-btn {
  padding: 1rem 2rem;
  font-size: 1.1rem;
  background: white;
  color: var(--primary);
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: transform 0.3s;
}

.cta-btn:hover {
  transform: translateY(-2px);
}

/* Courses Section */
.courses {
  padding: 4rem 2rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

.course-card {
  background: white;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  transition: transform 0.3s;
}

.course-card:hover {
  transform: translateY(-4px);
}

/* Modal Styles */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.5);
  z-index: 1000;
}

.modal-content {
  background: white;
  padding: 2rem;
  border-radius: 8px;
  max-width: 500px;
  margin: 2rem auto;
  position: relative;
}

.modal-content h2 {
  margin-bottom: 1.5rem;
}

form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

input {
  padding: 0.8rem;
  border: 1px solid #ddd;
  border-radius: 4px;
}

.google-btn {
  width: 100%;
  background: #DB4437;
  color: white;
  margin-top: 1rem;
}

/* Cart Styles */
#cartItems {
  margin: 1rem 0;
}

.cart-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0;
  border-bottom: 1px solid #ddd;
}

.cart-total {
  margin: 1rem 0;
  font-weight: bold;
  display: flex;
  justify-content: space-between;
}

/* Footer */
footer {
  background: var(--gray);
  padding: 4rem 2rem 1rem;
  margin-top: 4rem;
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

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

.footer-section a {
  display: block;
  color: var(--text);
  text-decoration: none;
  margin-bottom: 0.5rem;
}

.social-links {
  display: flex;
  gap: 1rem;
  margin-top: 1rem;
}

.footer-bottom {
  text-align: center;
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid #ddd;
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  
  .nav-auth {
    gap: 0.5rem;
  }
  
  .hero h1 {
    font-size: 2rem;
  }
}