:root {
  --primary-color: #2c3e50;
  --secondary-color: #3498db;
  --text-color: #333;
  --light-bg: #f8f9fa;
  --white: #ffffff;
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--white);
}

/* Header & Navigation */
header {
  background-color: var(--primary-color);
  padding: 1rem 0;
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 1000;
}

nav {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 2rem;
}

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

nav ul {
  display: flex;
  list-style: none;
  gap: 2rem;
}

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

nav a:hover {
  color: var(--secondary-color);
}

/* Hero Section */
.hero {
  background: linear-gradient(rgba(44, 62, 80, 0.9), rgba(44, 62, 80, 0.9)),
              url('https://images.unsplash.com/photo-1557804506-669a67965ba0?ixlib=rb-1.2.1&auto=format&fit=crop&w=1350&q=80');
  background-size: cover;
  background-position: center;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  color: var(--white);
  padding: 0 2rem;
}

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

.hero p {
  font-size: 1.5rem;
}

/* Courses Section */
.courses {
  padding: 5rem 2rem;
  background-color: var(--light-bg);
}

.courses h2 {
  text-align: center;
  margin-bottom: 3rem;
  font-size: 2.5rem;
}

.course-grid {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.course-card {
  background: var(--white);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

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

.course-card ul {
  margin: 1rem 0;
  padding-left: 1.5rem;
}

.price {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--primary-color);
  margin: 1rem 0;
}

button {
  background-color: var(--secondary-color);
  color: var(--white);
  border: none;
  padding: 0.8rem 1.5rem;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.3s;
}

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

/* Professor Section */
.professor {
  padding: 5rem 2rem;
}

.professor h2 {
  text-align: center;
  margin-bottom: 3rem;
  font-size: 2.5rem;
}

.professor-info {
  max-width: 800px;
  margin: 0 auto;
  background: var(--white);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.professor-content h3 {
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

.professor-content h4 {
  color: var(--secondary-color);
  margin-bottom: 1rem;
}

.professor-content ul {
  padding-left: 1.5rem;
}

/* Footer */
footer {
  background-color: var(--primary-color);
  color: var(--white);
  padding: 3rem 2rem 1rem;
}

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

.company-info, .contact-info {
  padding: 1rem;
}

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

.footer-bottom {
  text-align: center;
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Responsive Design */
@media (max-width: 768px) {
  nav {
    flex-direction: column;
    gap: 1rem;
  }

  nav ul {
    flex-direction: column;
    align-items: center;
    gap: 1rem;
  }

  .hero h1 {
    font-size: 2rem;
  }

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