:root {
  --color-bg: #f5f6f8;
  --color-surface: #ffffff;
  --color-text: #1a1a2e;
  --color-text-secondary: #5a5a7a;
  --color-primary: #3b5bdb;
  --color-primary-hover: #2b4bc8;
  --color-primary-light: #eef1fb;
  --color-danger: #e03131;
  --color-danger-hover: #c92a2a;
  --color-border: #dde1e8;
  --color-border-strong: #b0b8c9;
  --color-selected: #3b5bdb;
  --color-selected-bg: #eef1fb;
  --color-drop-active: #d0ebff;
  --color-drag-over: #a5d8ff;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --transition: 150ms ease;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
  min-height: 100vh;
}

/* Header */

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  gap: 1rem;
  flex-wrap: wrap;
}

.header-left h1 {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.subtitle {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.privacy-badge {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  background: var(--color-primary-light);
  padding: 0.25rem 0.75rem;
  border-radius: 100px;
  white-space: nowrap;
}

/* Buttons */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.5rem 1.2rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}

.btn:hover {
  border-color: var(--color-border-strong);
  background: var(--color-bg);
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
}

.btn-danger {
  color: var(--color-danger);
  border-color: var(--color-danger);
}

.btn-danger:hover {
  background: var(--color-danger);
  color: #fff;
}

.btn-small {
  padding: 0.35rem 0.8rem;
  font-size: 0.8rem;
}

.btn-icon {
  padding: 0.35rem 0.7rem;
  font-size: 0.8rem;
  font-weight: 600;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  cursor: pointer;
  transition: all var(--transition);
}

.btn-icon:hover {
  background: var(--color-bg);
}

.btn-icon-label {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.btn-icon-label svg {
  flex-shrink: 0;
}

/* Main layout */

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

/* Upload section */

#upload-section {
  margin-bottom: 1.5rem;
}

#upload-section.has-files .drop-zone {
  padding: 1rem;
  min-height: auto;
}

#upload-section.has-files .drop-zone-content {
  flex-direction: row;
  gap: 1rem;
  align-items: center;
}

#upload-section.has-files .drop-icon,
#upload-section.has-files .drop-or,
#upload-section.has-files .drop-hint,
#upload-section.has-files .drop-text {
  display: none;
}

#upload-section.has-files #btn-browse {
  display: inline-flex;
}

.drop-zone {
  border: 2px dashed var(--color-border-strong);
  border-radius: var(--radius-lg);
  padding: 3rem 2rem;
  text-align: center;
  transition: all var(--transition);
  background: var(--color-surface);
  min-height: 250px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.drop-zone.drag-over {
  border-color: var(--color-primary);
  background: var(--color-drop-active);
}

.drop-zone-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.drop-icon {
  color: var(--color-text-secondary);
  margin-bottom: 0.5rem;
}

.drop-text {
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--color-text);
}

.drop-or {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.drop-hint {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  margin-top: 0.5rem;
}

.error-text {
  color: var(--color-danger);
  font-size: 0.85rem;
  margin-top: 0.5rem;
  white-space: pre-line;
}

/* Toolbar */

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-sm);
  flex-wrap: wrap;
}

.toolbar.hidden {
  display: none;
}

.toolbar-left,
.toolbar-right {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.toolbar-sep {
  width: 1px;
  height: 1.2rem;
  background: var(--color-border);
  margin: 0 0.25rem;
}

.selection-status {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  margin-right: 0.5rem;
}

.combine-status {
  font-size: 0.8rem;
  color: var(--color-primary);
  font-weight: 500;
}

/* Page grid */

.grid-empty {
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  padding: 3rem 0;
}

.grid-empty.hidden {
  display: none;
}

.page-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 1rem;
  min-height: 50px;
}

/* Page cards */

.page-card {
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.5rem;
  cursor: pointer;
  transition: all var(--transition);
  user-select: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

.page-card:hover {
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-md);
}

.page-card.selected {
  border-color: var(--color-selected);
  background: var(--color-selected-bg);
}

.page-card.dragging {
  opacity: 0.3;
}

.page-card.drag-over-left {
  border-left: 3px solid var(--color-primary);
}

.page-card.drag-over-right {
  border-right: 3px solid var(--color-primary);
}

/* Order badge */

.order-badge {
  position: absolute;
  top: 4px;
  left: 4px;
  background: var(--color-text);
  color: #fff;
  font-size: 0.6rem;
  font-weight: 700;
  width: 1.3rem;
  height: 1.3rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2;
  line-height: 1;
}

.page-card.selected .order-badge {
  background: var(--color-primary);
}

/* Drag handle */

.drag-handle {
  position: absolute;
  top: 4px;
  right: 4px;
  color: var(--color-border-strong);
  cursor: grab;
  z-index: 2;
  padding: 2px;
  border-radius: 4px;
  transition: color var(--transition);
}

.drag-handle:hover {
  color: var(--color-text);
}

.page-card.dragging .drag-handle {
  cursor: grabbing;
}

.thumb-wrap {
  width: 100%;
  aspect-ratio: 210 / 297;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border-radius: 4px;
  background: #fafafa;
  transition: transform var(--transition);
}

.thumb-placeholder {
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #f0f0f0 25%, #e8e8e8 50%, #f0f0f0 75%);
  background-size: 200% 200%;
  animation: shimmer 1.5s ease-in-out infinite;
  border-radius: 4px;
}

@keyframes shimmer {
  0% { background-position: 200% 200%; }
  100% { background-position: -200% -200%; }
}

.thumb-canvas {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

.page-label {
  font-size: 0.7rem;
  color: var(--color-text);
  margin-top: 0.4rem;
  text-align: center;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  width: 100%;
  font-weight: 500;
}

.page-num {
  font-size: 0.65rem;
  color: var(--color-text-secondary);
  text-align: center;
}

/* Legal footer */

.legal-footer {
  max-width: 1200px;
  margin: 3rem auto 0;
  padding: 1.5rem 2rem;
  text-align: center;
  font-size: 0.7rem;
  line-height: 1.6;
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
}

.legal-footer p {
  margin-bottom: 0.4em;
}

.legal-footer a {
  color: var(--color-primary);
  text-decoration: none;
}

.legal-footer a:hover {
  text-decoration: underline;
}

.legal-footer .disclaimer {
  color: #888;
}

.legal-footer .impressum-license {
  font-style: italic;
  color: #888;
}

.impressum {
  margin-top: 0.8em;
  padding-top: 0.6em;
  border-top: 1px solid var(--color-border);
}

.impressum-toggle {
  color: var(--color-primary);
  text-decoration: none;
}

.impressum-toggle:hover {
  text-decoration: underline;
}

.impressum-content {
  margin-top: 0.4em;
}

.impressum-content[hidden] {
  display: none;
}

.impressum-logo {
  display: block;
  width: 30vw;
  max-width: 200px;
  height: auto;
  margin: 0 auto 0.3em;
  opacity: 0.7;
}

/* Responsive */

@media (max-width: 640px) {
  header {
    padding: 1rem;
    flex-direction: column;
    align-items: flex-start;
  }

  main {
    padding: 1rem;
  }

  .page-grid {
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 0.75rem;
  }

  .toolbar {
    flex-direction: column;
    align-items: flex-start;
  }

  .privacy-badge {
    display: none;
  }
}