body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f9f9f9;
}

header {
  background: #0077cc;
  color: white;
  padding: 15px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header h1 {
  margin: 0;
}

nav a, nav button {
  color: white;
  text-decoration: none;
  margin-left: 10px;
  background: #005fa3;
  padding: 6px 12px;
  border: none;
  cursor: pointer;
  border-radius: 4px;
}

nav button:hover, nav a:hover {
  background: #00457a;
}

main {
  padding: 20px;
}

.course-list {
  display: flex;
  gap: 20px;
}

.course-card {
  background: white;
  padding: 15px;
  border-radius: 6px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  flex: 1;
  transition: transform 0.2s;
}

.course-card:hover {
  transform: scale(1.05);
}

.course-card h3 {
  margin-top: 0;
}

button {
  background: #0077cc;
  color: white;
  padding: 10px 15px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
}

button:hover {
  background: #005fa3;
}

/* Progress bar */
.progress-container {
  margin: 20px 0;
}

.progress-bar {
  width: 100%;
  height: 20px;
  background: #ddd;
  border-radius: 10px;
  overflow: hidden;
}

#progressFill {
  height: 100%;
  width: 0%;
  background: #28a745;
}

/* Modal login */
.modal {
  display: none;
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.6);
  justify-content: center;
  align-items: center;
}

.modal-content {
  background: white;
  padding: 20px;
  border-radius: 8px;
  position: relative;
  width: 300px;
}

.modal-content input {
  display: block;
  width: 100%;
  margin: 10px 0;
  padding: 8px;
}

#closeModal {
  position: absolute;
  top: 10px; right: 15px;
  cursor: pointer;
  font-size: 20px;
}

#loginError {
  color: red;
  font-size: 14px;
}