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

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: #333;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
}

.container {
  max-width: 1400px;
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  padding: 1rem 2rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.title {
  color: white;
  font-size: 2rem;
  font-weight: 700;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.back-button {
  background: rgba(255, 255, 255, 0.2);
  color: white;
  border: none;
  padding: 10px 20px;
  border-radius: 25px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.3s ease;
  font-weight: 500;
}

.back-button:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
}

/* Main Content */
.main-content {
  flex: 1;
  padding: 2rem;
}

.actions-bar {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
}

.btn-primary,
.btn-secondary {
  padding: 12px 24px;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.3s ease;
}

.btn-primary {
  background: linear-gradient(135deg, #2196f3 0%, #1976d2 100%);
  color: white;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 16px rgba(33, 150, 243, 0.3);
}

.btn-secondary {
  background: white;
  color: #2196f3;
  border: 2px solid #2196f3;
}

.btn-secondary:hover {
  background: #2196f3;
  color: white;
}

/* Classes Grid */
.classes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 1.5rem;
  margin-bottom: 3rem;
}

.class-card {
  background: white;
  border-radius: 15px;
  padding: 1.5rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;
  border-left: 4px solid #e0e0e0;
}

.class-card.active {
  border-left-color: #4caf50;
}

.class-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.class-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.class-header h3 {
  color: #333;
  font-size: 1.2rem;
}

.class-actions {
  display: flex;
  gap: 0.5rem;
}

.class-actions button {
  background: none;
  border: none;
  padding: 8px;
  border-radius: 8px;
  cursor: pointer;
  color: #666;
  transition: all 0.3s ease;
}

.class-actions button:hover {
  background: #f5f5f5;
  color: #2196f3;
}

.class-info p {
  margin-bottom: 0.5rem;
  color: #666;
}

.class-status {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
  margin-top: 1rem;
}

.class-status.active {
  background: #e8f5e8;
  color: #4caf50;
}

.class-status.pending {
  background: #fff3e0;
  color: #ff9800;
}

/* Schedule Section */
.schedule-section {
  background: white;
  border-radius: 15px;
  padding: 2rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.schedule-section h2 {
  margin-bottom: 1.5rem;
  color: #333;
}

.schedule-grid {
  display: grid;
  grid-template-columns: 120px repeat(5, 1fr);
  gap: 1px;
  background: #e0e0e0;
  border-radius: 10px;
  overflow: hidden;
}

.time-slot {
  background: #f5f5f5;
  padding: 1rem;
  font-weight: 600;
  color: #666;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.schedule-item {
  background: white;
  padding: 1rem;
  text-align: center;
  font-size: 0.9rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 80px;
}

.schedule-item.active {
  background: #e3f2fd;
  color: #2196f3;
  font-weight: 500;
}

.schedule-item.pending {
  background: #fff3e0;
  color: #ff9800;
  font-weight: 500;
}

.empty-slot {
  background: white;
  min-height: 80px;
}

/* Modal Styles */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal-overlay.active {
  display: flex;
}

.modal {
  background: white;
  border-radius: 20px;
  width: 90%;
  max-width: 600px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.modal-header {
  padding: 1.5rem;
  border-bottom: 1px solid #f0f0f0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-header h3 {
  font-size: 1.2rem;
  color: #333;
}

.close-modal {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: #666;
}

.modal-body {
  padding: 1.5rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  color: #333;
  font-weight: 500;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 10px;
  border: 2px solid #f0f0f0;
  border-radius: 10px;
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: #2196f3;
}

.checkbox-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.checkbox-group label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: normal;
  margin-bottom: 0;
}

.modal-footer {
  padding: 1.5rem;
  border-top: 1px solid #f0f0f0;
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
}

.btn-cancel,
.btn-save {
  padding: 10px 20px;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
}

.btn-cancel {
  background: #f5f5f5;
  color: #666;
}

.btn-cancel:hover {
  background: #e0e0e0;
}

.btn-save {
  background: linear-gradient(135deg, #2196f3 0%, #1976d2 100%);
  color: white;
}

.btn-save:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 16px rgba(33, 150, 243, 0.3);
}

/* Responsive */
@media (max-width: 768px) {
  .main-content {
    padding: 1rem;
  }

  .header {
    padding: 1rem;
  }

  .header-content {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .title {
    font-size: 1.5rem;
  }

  .classes-grid {
    grid-template-columns: 1fr;
  }

  .schedule-grid {
    grid-template-columns: 100px repeat(3, 1fr);
    font-size: 0.8rem;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .actions-bar {
    flex-direction: column;
  }
}