body {
  font-family: 'Segoe UI', sans-serif;
  margin: 0;
  background: #f9f9f9;
  color: #333;
}

header nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #004aad;
  padding: 1rem 2rem;
  color: white;
}

nav .logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: white;
  text-decoration: none;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 1rem;
}

nav ul li a {
  color: white;
  text-decoration: none;
}

nav ul li .signup {
  background: #ff4d4d;
  padding: 0.5rem 1rem;
  border-radius: 5px;
}

.hero {
  text-align: center;
  padding: 2rem;
  background: #e6f0ff;
}

/* Filters */
.filters {
  display: flex;
  gap: 1rem;
  padding: 1rem 2rem;
  flex-wrap: wrap;
  justify-content: center;
}

.filters input, .filters select {
  padding: 0.5rem;
  border: 1px solid #ccc;
  border-radius: 6px;
}

.tab {
  padding: 0.5rem 1rem;
  border: none;
  background: #ddd;
  cursor: pointer;
}

.tab.active {
  background: #004aad;
  color: white;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  padding: 2rem;
}

.course-card {
  background: white;
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  text-align: center;
  cursor: pointer;
}

.course-card img {
  width: 100%;
  height: 150px;
  object-fit: cover;
  border-radius: 6px;
}

.enroll {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  background: #004aad;
  color: white;
  text-decoration: none;
  border-radius: 5px;
}

/* Mentor Preview */
.mentor-preview {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.5rem;
  justify-content: center;
}

.mentor-preview img {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
}

.upcoming {
  padding: 2rem;
  background: #fff0f5;
}

footer {
  text-align: center;
  padding: 1rem;
  background: #004aad;
  color: white;
}

/* Modal */
.modal {
  display: none; /* hidden by default */
  position: fixed;
  z-index: 1000;
  left: 0; top: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.6);
}

.modal-content {
  background: #fff;
  margin: 10% auto;
  padding: 2rem;
  border-radius: 8px;
  width: 80%;
  max-width: 600px;
  position: relative;
}

.modal .close {
  position: absolute;
  top: 10px; right: 15px;
  font-size: 1.5rem;
  cursor: pointer;
}