:root {
  --border: #b0bec5;
  --text-primary: #2d3748;
  --text-secondary: #718096;
  --error: #c0392b;
  --button-bg: #e2e8f0;
}

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

html,
body {
  height: 100%;
  overflow: hidden;
}

[hidden] {
  display: none !important;
}

#app {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr;
  height: 100vh;
}

.left-panel {
  display: flex;
  flex-direction: column;
  border-right: 1px solid #ccc;
  overflow: hidden;
}

.right-panel {
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.panel {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  flex: 1;
  min-height: 0;
}

.editor-panel {
  background-color: #f0f4f8;
}

.reader-panel {
  background-color: #fafafa;
}

.js-add-layer,
.js-undo-last,
.js-save,
.js-load,
.js-commit-page,
.js-save-chapter,
.js-load-chapter,
.js-undo-page {
  display: block;
  width: 100%;
  padding: 10px 16px;
  cursor: pointer;
  background-color: var(--button-bg);
  border: 1px solid var(--border);
  font-size: 0.9rem;
  font-weight: 600;
  text-align: center;
  color: var(--text-primary);
}

.js-add-layer:disabled,
.js-undo-last:disabled,
.js-save:disabled,
.js-commit-page:disabled,
.js-save-chapter:disabled,
.js-undo-page:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.editor-layer-error {
  min-height: 1em;
  font-size: 0.8rem;
  color: var(--error);
}

.editor-layers-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 8px 0;
}

.editor-layer-thumb {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.editor-layer-thumb img {
  display: block;
  max-width: 80px;
  max-height: 80px;
  object-fit: contain;
  border: 1px solid var(--border);
}

.editor-layer-thumb .layer-index {
  font-size: 0.7rem;
  color: var(--text-secondary);
  line-height: 1;
}

.editor-layers-strip .editor-layers-empty {
  color: #90a4ae;
  font-style: italic;
  font-size: 0.85rem;
}

.reader-page-area {
  position: relative;
  flex: 1;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.reader-chrome {
  flex-shrink: 0;
  min-height: 3rem;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1rem;
}

.reader-chrome button {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.25rem;
  padding: 0.25rem 0.5rem;
}

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

#reader-page-box {
  position: relative;
  overflow: hidden;
}

#reader-page-box img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.reader-end-text,
.reader-idle-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 0.875rem;
  color: #888;
}

.reader-idle-text {
  pointer-events: none;
}

.js-chapter-number,
.js-chapter-title {
  display: block;
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--border);
  background-color: #fff;
  font-size: 0.9rem;
  color: var(--text-primary);
}

.chapter-error {
  min-height: 1em;
  font-size: 0.8rem;
  color: var(--error);
  font-style: italic;
}

.chapter-page-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  overflow-y: auto;
  flex: 1;
  min-height: 0;
}

.chapter-page-item {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem;
  background-color: var(--button-bg);
  border: 1px solid var(--border);
}

.chapter-page-item img {
  display: block;
  width: 60px;
  height: 60px;
  object-fit: contain;
  border: 1px solid var(--border);
  flex-shrink: 0;
}

.chapter-page-item .page-label {
  flex: 1;
  font-size: 0.85rem;
  color: var(--text-primary);
}