.cards-panel {
  margin-top: 32px;
  padding: 24px;
  background: #ffffff;
  border-radius: 20px;
  box-shadow: 0 20px 60px rgba(15, 23, 42, 0.08);
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.cards-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.cards-title {
  font-size: 18px;
  font-weight: 600;
  color: #111827;
}

.cards-count {
  font-size: 14px;
  color: #6b7280;
}

.cards-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.sequence-card {
  flex: 1 1 calc(25% - 20px);
  min-width: 220px;
  max-width: 320px;
  background: linear-gradient(135deg, #ffffff 0%, #f9fafb 100%);
  border-radius: 16px;
  border: 1px solid rgba(99, 102, 241, 0.15);
  box-shadow: 0 12px 30px rgba(99, 102, 241, 0.1);
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
  cursor: pointer;
  display: flex;
  flex-direction: column;
}

.sequence-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 18px 45px rgba(99, 102, 241, 0.18);
  border-color: rgba(99, 102, 241, 0.4);
}

.sequence-card.is-active {
  border-color: #6366f1;
  box-shadow: 0 22px 55px rgba(99, 102, 241, 0.3);
}

.card-content {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.image-container {
  position: relative;
  width: 100%;
  padding: 12px;
  min-height: 180px;
  display: flex;
  align-items: center;
  justify-content: center;
  /* 棋盘格背景用于显示透明部分 */
  background-color: #fefefe;
  background-image: 
    linear-gradient(45deg, #e5e7eb 25%, transparent 25%),
    linear-gradient(-45deg, #e5e7eb 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #e5e7eb 75%),
    linear-gradient(-45deg, transparent 75%, #e5e7eb 75%);
  background-size: 12px 12px;
  background-position: 0 0, 0 6px, 6px -6px, -6px 0px;
  border-radius: 12px;
}

.card-image {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  image-rendering: pixelated;
  border-radius: 10px;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 18px;
  gap: 12px;
}

.card-label {
  font-size: 14px;
  font-weight: 600;
  color: #1f2937;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.card-download-btn {
  width: 36px;
  height: 36px;
  border: none;
  border-radius: 999px;
  background: linear-gradient(135deg, #6366f1, #8b5cf6);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  box-shadow: 0 8px 18px rgba(99, 102, 241, 0.35);
}

.card-download-btn:hover {
  transform: scale(1.1);
  background: linear-gradient(135deg, #4f46e5, #7c3aed);
}

.card-download-btn:active {
  transform: scale(0.94);
}

.sequence-card .loading-spinner {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: 3px solid #e0e7ff;
  border-top-color: #6366f1;
  animation: spin 0.8s linear infinite;
  transform: translate(-50%, -50%);
}

.sequence-card .image-error {
  position: absolute;
  top: 12px;
  right: 12px;
  padding: 6px 10px;
  font-size: 12px;
  border-radius: 6px;
  background: rgba(239, 68, 68, 0.9);
  color: #fff;
}

@keyframes spin {
  to {
    transform: translate(-50%, -50%) rotate(360deg);
  }
}

@media (max-width: 1200px) {
  .sequence-card {
    flex: 1 1 calc(33.333% - 20px);
  }
}

@media (max-width: 900px) {
  .sequence-card {
    flex: 1 1 calc(50% - 20px);
  }
}

@media (max-width: 600px) {
  .sequence-card {
    flex: 1 1 100%;
  }
}

/* ========================================
   预览卡片 (主预览区域)
   ======================================== */

.preview-card {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.preview-card-stage {
  width: 100%;
  flex: 1;
  border-radius: 16px;
  /* 棋盘格背景用于显示透明部分 */
  background-color: #f8f9fb;
  background-image: 
    linear-gradient(45deg, #e5e7eb 25%, transparent 25%),
    linear-gradient(-45deg, #e5e7eb 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #e5e7eb 75%),
    linear-gradient(-45deg, transparent 75%, #e5e7eb 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
  min-height: 75vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  border: 2px dashed #d1d5db;
  box-shadow: inset 0 0 0 1px #edf0f6;
  transition: all 0.3s ease;
}

.preview-card-stage.is-dragging {
  background: #f0f7ff;
  border: 3px dashed #3b82f6;
  box-shadow: inset 0 0 0 8px rgba(59, 130, 246, 0.1);
}

.preview-card-stage.is-dragging-invalid {
  background: #fef2f2;
  border: 3px dashed #ef4444;
  box-shadow: inset 0 0 0 8px rgba(239, 68, 68, 0.1);
  cursor: not-allowed;
}

.preview-card-stage.is-dragging-invalid::after {
  content: "🚫 不支持的内容";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 20px;
  font-weight: 600;
  color: #dc2626;
  background: rgba(254, 242, 242, 0.95);
  padding: 16px 32px;
  border-radius: 12px;
  border: 2px solid #ef4444;
  pointer-events: none;
  z-index: 100;
}

.preview-card-stage.is-playing {
  border: none;
  background: #ffffff;
  box-shadow: none;
}

/* 顶部信息栏 */
.preview-info-bar {
  position: absolute;
  top: 16px;
  left: 16px;
  right: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 10;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.preview-info-bar:not([hidden]) {
  opacity: 1;
}

.folder-info {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  background: rgba(255, 255, 255, 0.95);
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
  backdrop-filter: blur(4px);
}

.folder-icon {
  color: #f59e0b;
  flex-shrink: 0;
}

.folder-name {
  font-size: 14px;
  font-weight: 600;
  color: #374151;
  max-width: 200px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* 操作按钮组 */
.preview-action-btns {
  display: flex;
  gap: 8px;
}

.btn-action {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: none;
  border-radius: 10px;
  color: white;
  cursor: pointer;
  backdrop-filter: blur(4px);
  transition: all 0.2s ease;
}

.btn-action.btn-ai {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  box-shadow: 0 2px 12px rgba(16, 185, 129, 0.3);
}

.btn-action.btn-ai:hover {
  background: linear-gradient(135deg, #34d399 0%, #10b981 100%);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(16, 185, 129, 0.4);
}

.btn-action.btn-download {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  box-shadow: 0 2px 12px rgba(102, 126, 234, 0.3);
}

.btn-action.btn-download:hover {
  background: linear-gradient(135deg, #7c8ef0 0%, #8a5fb8 100%);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(102, 126, 234, 0.4);
}

.btn-action:active {
  transform: translateY(0);
}

.btn-action svg {
  width: 20px;
  height: 20px;
}

.btn-action .ai-icon {
  font-size: 14px;
  font-weight: 800;
  letter-spacing: -0.5px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

/* 旧的导出按钮样式（保留兼容性） */
.btn-export {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px 16px;
  background: rgba(139, 92, 246, 0.95);
  border: none;
  border-radius: 8px;
  color: white;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 2px 12px rgba(139, 92, 246, 0.3);
  backdrop-filter: blur(4px);
  transition: all 0.2s ease;
  white-space: nowrap;
}

.btn-export:hover {
  background: rgba(124, 58, 237, 0.95);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(139, 92, 246, 0.4);
}

.btn-export:active {
  transform: translateY(0);
}

.preview-card-stage .preview-image {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  image-rendering: pixelated;
  z-index: 1;
}

.preview-card-stage .preview-image:not([src]),
.preview-card-stage .preview-image[src=""],
.preview-card-stage .preview-image.is-hidden {
  opacity: 0;
  visibility: hidden;
  display: none;
}

.preview-card-stage .loading-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  background: rgba(248, 249, 251, 0.92);
  backdrop-filter: blur(4px);
  z-index: 50;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.preview-card-stage .loading-overlay.is-visible {
  opacity: 1;
  visibility: visible;
}

.preview-card-stage .loading-spinner {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: 4px solid rgba(59, 130, 246, 0.15);
  border-top-color: #3b82f6;
  animation: spin-preview 0.8s cubic-bezier(0.45, 0.05, 0.55, 0.95) infinite;
  position: relative;
}

.preview-card-stage .loading-spinner::before {
  content: "";
  position: absolute;
  inset: -12px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.1) 0%, transparent 70%);
  animation: pulse-glow 1.5s ease-in-out infinite;
}

.preview-card-stage .loading-text {
  margin: 0;
  font-size: 14px;
  font-weight: 500;
  color: #6b7280;
  letter-spacing: 0.02em;
  animation: fade-pulse 1.5s ease-in-out infinite;
}

.preview-card-stage .image-error {
  position: absolute;
  top: 24px;
  left: 24px;
  padding: 10px 16px;
  border-radius: 12px;
  background: rgba(120, 124, 138, 0.92);
  color: #fff;
  font-size: 15px;
  z-index: 20;
}

.preview-card-stage .drop-hint {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  z-index: 5;
}

.preview-card-stage .drop-hint[hidden] {
  display: none;
}

.preview-card-stage .hint-text {
  margin: 0;
  padding: 0;
  font-size: 20px;
  font-weight: 600;
  color: #9ca3af;
  letter-spacing: 1px;
  text-align: center;
}

.preview-card-controls {
  width: 100%;
  flex-shrink: 0;
  background: transparent;
  padding: 16px 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
}

.preview-card-controls .control-label {
  font-size: 14px;
  font-weight: 600;
  color: #9ca3af;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.preview-card-controls .slider-container {
  display: flex;
  align-items: center;
  gap: 18px;
  flex: 1;
  max-width: 520px;
  padding: 16px 18px;
  border-radius: 18px;
  background: #f4f6fb;
  box-shadow: inset 0 0 0 1px #e7eaf2;
}

.preview-card-controls .fps-slider {
  flex: 1;
  height: 10px;
  -webkit-appearance: none;
  appearance: none;
  background: linear-gradient(90deg, #e5e7eb 0%, #c7ccd9 100%);
  border-radius: 999px;
  outline: none;
  cursor: pointer;
  transition: background 0.2s ease, box-shadow 0.2s ease;
  box-shadow: inset 0 2px 6px rgba(15, 23, 42, 0.08);
}

.preview-card-controls .fps-slider::-webkit-slider-runnable-track {
  height: 10px;
  border-radius: 999px;
  background: transparent;
}

.preview-card-controls .fps-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  background: #111827;
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(17, 24, 39, 0.25);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  margin-top: -6px;
}

.preview-card-controls .fps-slider::-webkit-slider-thumb:hover {
  transform: scale(1.15);
  box-shadow: 0 8px 22px rgba(17, 24, 39, 0.3);
}

.preview-card-controls .fps-slider::-webkit-slider-thumb:active {
  transform: scale(1.05);
}

.preview-card-controls .fps-value {
  min-width: 88px;
  padding: 8px 14px;
  background: #111827;
  color: #ffffff;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  text-align: center;
  font-family: "SF Mono", "Monaco", "Inconsolata", "Roboto Mono", monospace;
  box-shadow: 0 8px 20px rgba(15, 23, 42, 0.25);
}

@keyframes spin-preview {
  to {
    transform: rotate(360deg);
  }
}

@keyframes pulse-glow {
  0%, 100% {
    transform: scale(0.9);
    opacity: 0.5;
  }
  50% {
    transform: scale(1.1);
    opacity: 1;
  }
}

@keyframes fade-pulse {
  0%, 100% {
    opacity: 0.6;
  }
  50% {
    opacity: 1;
  }
}

@media (max-width: 900px) {
  .preview-card-stage {
    min-height: 60vh;
  }
  
  .preview-card-controls {
    flex-direction: column;
  }
  
  .preview-card-controls .slider-container {
    width: 100%;
  }
}