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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f5f5f5;
}

/* Session Banner */
.session-banner {
  background: #2c3e50;
  color: #ecf0f1;
  padding: 8px 20px;
  font-size: 11px;
  font-family: monospace;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.session-banner .session-id {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.session-banner span {
  opacity: 0.8;
}

.session-banner strong {
  color: #3498db;
  opacity: 1;
}

.session-banner .reset-session-btn {
  background: none;
  border: 1px solid rgba(255,255,255,0.3);
  color: #ecf0f1;
  font-family: monospace;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 3px;
  cursor: pointer;
  opacity: 0.7;
  transition: opacity 0.15s;
}

.session-banner .reset-session-btn:hover {
  opacity: 1;
}

/* Header */
header {
  background: white;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.logo {
  font-size: 24px;
  font-weight: bold;
  color: #2c3e50;
  text-decoration: none;
}

.logo:hover {
  color: #3498db;
}

.search-bar {
  flex: 1;
  max-width: 500px;
  min-width: 200px;
}

.search-bar input {
  width: 100%;
  padding: 10px 15px;
  border: 2px solid #ddd;
  border-radius: 4px;
  font-size: 14px;
}

.search-bar input:focus {
  outline: none;
  border-color: #3498db;
}

.nav-links {
  display: flex;
  gap: 20px;
  align-items: center;
}

.nav-links a {
  color: #2c3e50;
  text-decoration: none;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: 4px;
  transition: all 0.3s;
}

.nav-links a:hover {
  background: #ecf0f1;
  color: #3498db;
}

.btn-primary {
  background: #3498db;
  color: white;
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  display: inline-block;
  transition: background 0.3s;
}

.btn-primary:hover {
  background: #2980b9;
}

/* Main Content */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 40px 20px;
  min-height: 80vh;
}

/* Filters */
.filters {
  background: white;
  padding: 20px;
  border-radius: 8px;
  margin-bottom: 30px;
  display: flex;
  gap: 15px;
  flex-wrap: wrap;
  align-items: center;
}

.filters label {
  font-weight: 500;
  margin-right: 5px;
}

.filters select,
.filters input {
  padding: 8px 12px;
  border: 2px solid #ddd;
  border-radius: 4px;
  font-size: 14px;
}

.filters select:focus,
.filters input:focus {
  outline: none;
  border-color: #3498db;
}

/* Product Grid */
.product-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 30px;
  margin-bottom: 40px;
}

.product-card {
  background: white;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  transition: transform 0.3s, box-shadow 0.3s;
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  display: block;
}

.product-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}

.product-image {
  width: 100%;
  height: 300px;
  object-fit: cover;
  background: #ecf0f1;
}

.product-info {
  padding: 20px;
}

.product-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 5px;
  color: #2c3e50;
}

.product-artist {
  font-size: 14px;
  color: #7f8c8d;
  margin-bottom: 10px;
}

.product-meta {
  font-size: 13px;
  color: #95a5a6;
  margin-bottom: 10px;
}

.product-price {
  font-size: 20px;
  font-weight: bold;
  color: #27ae60;
}

/* Pagination */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 10px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.pagination button,
.pagination a {
  padding: 10px 15px;
  border: 2px solid #ddd;
  background: white;
  color: #2c3e50;
  border-radius: 4px;
  cursor: pointer;
  text-decoration: none;
  font-weight: 500;
  transition: all 0.3s;
}

.pagination button:hover:not(:disabled),
.pagination a:hover {
  border-color: #3498db;
  color: #3498db;
}

.pagination button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.pagination .active {
  background: #3498db;
  color: white;
  border-color: #3498db;
}

.pagination-info {
  color: #7f8c8d;
  font-size: 14px;
}

/* Product Detail Page */
.product-detail {
  background: white;
  border-radius: 8px;
  padding: 40px;
  max-width: 1200px;
  margin: 0 auto;
}

.product-detail-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
}

.product-detail-image {
  width: 100%;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.product-detail-info h1 {
  font-size: 32px;
  margin-bottom: 10px;
  color: #2c3e50;
}

.product-detail-info .artist {
  font-size: 18px;
  color: #7f8c8d;
  margin-bottom: 20px;
}

.product-detail-info .price {
  font-size: 36px;
  font-weight: bold;
  color: #27ae60;
  margin-bottom: 30px;
}

.product-details-list {
  list-style: none;
  margin-bottom: 30px;
}

.product-details-list li {
  padding: 12px 0;
  border-bottom: 1px solid #ecf0f1;
  display: flex;
  justify-content: space-between;
}

.product-details-list li strong {
  color: #2c3e50;
}

.product-details-list li span {
  color: #7f8c8d;
}

.product-description {
  color: #555;
  line-height: 1.8;
  margin-bottom: 30px;
}

/* Login Page */
.login-container {
  max-width: 400px;
  margin: 80px auto;
  background: white;
  padding: 40px;
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.1);
}

.login-container h1 {
  margin-bottom: 30px;
  color: #2c3e50;
  text-align: center;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  color: #2c3e50;
}

.form-group input {
  width: 100%;
  padding: 12px;
  border: 2px solid #ddd;
  border-radius: 4px;
  font-size: 14px;
}

.form-group input:focus {
  outline: none;
  border-color: #3498db;
}

.btn-block {
  width: 100%;
  padding: 12px;
  margin-top: 10px;
}

.error-message {
  background: #fee;
  color: #c33;
  padding: 12px;
  border-radius: 4px;
  margin-bottom: 20px;
  text-align: center;
}

/* Account Page */
.account-container {
  max-width: 800px;
  margin: 0 auto;
  background: white;
  padding: 40px;
  border-radius: 8px;
}

.account-container h1 {
  margin-bottom: 30px;
  color: #2c3e50;
}

.account-info {
  display: grid;
  gap: 20px;
}

.info-item {
  padding: 20px;
  background: #f8f9fa;
  border-radius: 4px;
  border-left: 4px solid #3498db;
}

.info-item label {
  display: block;
  font-size: 12px;
  color: #7f8c8d;
  text-transform: uppercase;
  margin-bottom: 5px;
}

.info-item .value {
  font-size: 16px;
  color: #2c3e50;
  font-weight: 500;
}

/* Footer */
footer {
  background: #2c3e50;
  color: #ecf0f1;
  padding: 40px 20px;
  margin-top: 60px;
}

.footer-content {
  max-width: 1400px;
  margin: 0 auto;
  text-align: center;
}

.footer-content p {
  opacity: 0.8;
}

/* Loading State */
.loading {
  text-align: center;
  padding: 60px 20px;
  color: #7f8c8d;
}

/* Responsive */
@media (max-width: 768px) {
  .product-detail-content {
    grid-template-columns: 1fr;
    gap: 30px;
  }

  .product-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 20px;
  }

  .header-content {
    flex-direction: column;
  }

  .search-bar {
    max-width: 100%;
  }
}