.course-player-section {
  padding: 60px 0;
  background: #fff;
}

.lesson-sidebar {
  background: linear-gradient(180deg, #f8f9fa 0%, #e9ecef 100%);
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  top: 100px;
  max-height: calc(100vh - 120px);
  overflow-y: auto;
}

.lesson-sidebar h3 {
  font-family: 'Poppins', sans-serif;
  font-weight: 700;
  font-size: 1.5rem;
  color: #1a1a1a;
  margin-bottom: 20px;
}

.lesson-menu {
  list-style: none;
  padding: 0;
}

.lesson-menu li {
  margin-bottom: 10px;
}

.lesson-menu a {
  display: block;
  padding: 10px 15px;
  font-family: 'Roboto', sans-serif;
  font-size: 0.9rem;
  color: #4a4a4a;
  text-decoration: none;
  border-radius: 6px;
  transition: background 0.3s ease, color 0.3s ease;
}

.lesson-menu a:hover,
.lesson-menu a.active {
  background: linear-gradient(45deg, #f26c21, #f39c12);
  color: #fff;
}

.lesson-menu a.completed::after {
  content: '\2713';
  margin-left: 10px;
  color: #fff;
}

.course-progress {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 20px;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: #e0e0e0;
  border-radius: 4px;
  overflow: hidden;
  flex-grow: 1;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(45deg, #f26c21, #f39c12);
  transition: width 0.3s ease;
}

.progress-text {
  font-family: 'Roboto', sans-serif;
  font-size: 0.9rem;
  color: #4a4a4a;
}

.course-content {
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  padding: 20px;
  min-height: 400px;
}

.course-content h3 {
  font-family: 'Poppins', sans-serif;
  font-weight: 700;
  font-size: 1.5rem;
  color: #1a1a1a;
  margin-bottom: 15px;
}

.course-content video,
.course-content iframe {
  width: 100%;
  height: 400px;
  border-radius: 8px;
  margin-bottom: 20px;
}

.course-content .lesson-text {
  font-family: 'Roboto', sans-serif;
  font-size: 1rem;
  color: #4a4a4a;
  line-height: 1.6;
  margin-bottom: 20px;
}

.course-content .pdf-viewer {
  width: 100%;
  height: 500px;
  border: none;
  border-radius: 8px;
  margin-bottom: 20px;
}

.course-content .quiz-form {
  margin-bottom: 20px;
}

.course-content .quiz-form label {
  font-family: 'Roboto', sans-serif;
  font-size: 0.95rem;
  color: #1a1a1a;
  margin-bottom: 10px;
  display: block;
}

.course-content .quiz-form input[type="radio"] {
  margin-right: 5px;
}

.course-content .code-editor {
  margin-bottom: 20px;
}

.course-content .code-editor textarea {
  width: 100%;
  height: 200px;
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  padding: 10px;
  border-radius: 5px;
  border: 1px solid #e0e0e0;
  resize: vertical;
}

.course-content .code-output {
  font-family: 'Roboto', sans-serif;
  font-size: 0.9rem;
  color: #4a4a4a;
  margin-top: 10px;
}

.course-navigation {
  display: flex;
  gap: 10px;
  justify-content: flex-end;
  margin-top: 20px;
}

.nav-button {
  padding: 10px 20px;
  background: linear-gradient(45deg, #f26c21, #f39c12);
  color: #fff;
  font-family: 'Poppins', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.3s ease, transform 0.3s ease;
}

.nav-button:disabled {
  background: #ccc;
  cursor: not-allowed;
}

.nav-button:hover:not(:disabled) {
  background: linear-gradient(45deg, #f39c12, #f26c21);
  transform: translateY(-2px);
}

.recommendations {
  margin-top: 40px;
}

.recommendations h3 {
  font-family: 'Poppins', sans-serif;
  font-weight: 700;
  font-size: 1.5rem;
  color: #1a1a1a;
  margin-bottom: 20px;
}

.recommendation-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.recommendation-card {
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  overflow: hidden;
  transition: transform 0.3s ease;
}

.recommendation-card:hover {
  transform: translateY(-5px);
}

.recommendation-card img {
  width: 100%;
  height: 150px;
  object-fit: cover;
}

.recommendation-card h4 {
  font-family: 'Poppins', sans-serif;
  font-weight: 600;
  font-size: 1.2rem;
  color: #1a1a1a;
  margin: 10px;
}

.recommendation-card p {
  font-family: 'Roboto', sans-serif;
  font-size: 0.9rem;
  color: #4a4a4a;
  margin: 0 10px 10px;
}

.recommendation-card .details-link {
  display: block;
  margin: 10px;
  padding: 8px 16px;
  background: linear-gradient(45deg, #f26c21, #f39c12);
  color: #fff;
  font-family: 'Poppins', sans-serif;
  font-weight: 600;
  text-align: center;
  border-radius: 6px;
  text-decoration: none;
}

.recommendation-card .details-link:hover {
  background: linear-gradient(45deg, #f39c12, #f26c21);
}

@media (max-width: 991px) {
  .lesson-sidebar {
    position: static;
    margin-bottom: 20px;
    max-height: none;
  }
  .course-content video,
  .course-content iframe {
    height: 300px;
  }
  .course-content .pdf-viewer {
    height: 400px;
  }
}

@media (max-width: 768px) {
  .course-player-section {
    padding: 40px 0;
  }
  .lesson-menu a {
    font-size: 0.85rem;
    padding: 8px 12px;
  }
  .course-content h3 {
    font-size: 1.3rem;
  }
  .course-content .lesson-text {
    font-size: 0.95rem;
  }
}

@media (max-width: 576px) {
  .course-content video,
  .course-content iframe {
    height: 200px;
  }
  .course-content .pdf-viewer {
    height: 300px;
  }
  .course-content h3 {
    font-size: 1.2rem;
  }
  .nav-button {
    font-size: 0.85rem;
    padding: 8px 15px;
  }
  .recommendation-card img {
    height: 120px;
  }
}