:root {
  --bg-color: #e7dbc2;
  --surface-color: #f6efe0;
  --surface-shadow: rgba(88, 63, 29, 0.18);
  --text-color: #2c231b;
  --muted-color: #7a6651;
  --accent-color: #6e4e2c;
  --accent-strong: #4e351c;
  --border-color: rgba(110, 78, 44, 0.22);
  --font-family: "Noto Serif SC", Georgia, serif;
  --font-size: 18px;
  --line-height: 1.8;
}

html {
  height: 100%;
}

body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background:
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.55), transparent 30%),
    linear-gradient(135deg, #d7c7aa, var(--bg-color));
  color: var(--text-color);
  font-family: var(--font-family);
}

body[data-theme="sepia"] {
  --bg-color: #d9c4a6;
  --surface-color: #f3e6cb;
  --text-color: #3a2a16;
  --accent-color: #8c5227;
}

body[data-theme="night"] {
  --bg-color: #1a1f28;
  --surface-color: #232b37;
  --surface-shadow: rgba(0, 0, 0, 0.35);
  --text-color: #e6dccb;
  --muted-color: #b5a995;
  --accent-color: #d1a15d;
  --accent-strong: #f5c47a;
  --border-color: rgba(245, 196, 122, 0.16);
}

button,
select,
input {
  font: inherit;
}

button,
.file-picker span {
  border: 1px solid var(--border-color);
  border-radius: 999px;
  padding: 10px 14px;
  background: rgba(255, 255, 255, 0.35);
  color: var(--text-color);
  cursor: pointer;
}

.icon-button {
  position: relative;
  width: 42px;
  height: 42px;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.icon-frame {
  position: relative;
  width: 16px;
  height: 16px;
  display: inline-block;
}

.icon-frame::before,
.icon-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  border-color: currentColor;
}

.icon-frame::before {
  border-top: 2px solid currentColor;
  border-left: 2px solid currentColor;
}

.icon-frame::after {
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
}

.icon-frame.exit {
  transform: scale(0.86);
}

.icon-frame.exit::before {
  inset: 3px 3px auto auto;
  width: 8px;
  height: 8px;
  border-top: 2px solid currentColor;
  border-left: 2px solid currentColor;
}

.icon-frame.exit::after {
  inset: auto auto 3px 3px;
  width: 8px;
  height: 8px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
}

button:hover,
.file-picker span:hover {
  border-color: var(--accent-color);
}

button:focus-visible,
select:focus-visible,
input:focus-visible {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

.app-shell {
  display: grid;
  grid-template-columns: 320px 1fr;
  height: 100vh;
  overflow: hidden;
  transition: grid-template-columns 240ms ease;
}

.app-shell.panel-hidden {
  grid-template-columns: 0 1fr;
}

body.is-immersive .app-shell {
  grid-template-columns: 0 1fr;
  background: transparent;
}

.side-panel {
  padding: 24px 18px;
  border-right: 1px solid var(--border-color);
  backdrop-filter: blur(12px);
  background: rgba(255, 250, 243, 0.35);
  height: 100%;
  box-sizing: border-box;
  overflow-y: auto;
  overflow-x: hidden;
  transition: opacity 200ms ease;
}

.app-shell.panel-hidden .side-panel {
  opacity: 0;
  pointer-events: none;
}

body.is-immersive .side-panel {
  opacity: 0;
  pointer-events: none;
}

.panel-block + .panel-block {
  margin-top: 20px;
}

.panel-label,
.eyebrow {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted-color);
}

.file-picker input {
  display: none;
}

.file-picker span {
  display: inline-flex;
  width: calc(100% - 30px);
  justify-content: center;
}

.inline-picker span {
  width: auto;
}

.action-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.library-actions {
  margin-top: 8px;
}

#close-current-book {
  width: 100%;
}

.reset-panel {
  margin-top: 12px;
  padding: 10px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.2);
  display: grid;
  gap: 8px;
}

.reset-label {
  margin-top: 0;
}

.reset-option {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--muted-color);
}

.reset-option input {
  margin: 0;
}

.file-meta,
.counter {
  margin: 8px 0 0;
  font-size: 13px;
  color: var(--muted-color);
}

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

.small-button {
  padding: 8px 12px;
  font-size: 13px;
}

.list {
  display: grid;
  gap: 8px;
  max-height: 220px;
  overflow: auto;
}

.list button {
  border-radius: 16px;
  text-align: left;
  line-height: 1.5;
}

.bookmark-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
}

.stats-list {
  display: grid;
  gap: 8px;
}

.stats-item {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 8px 10px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.24);
  font-size: 13px;
}

.stats-item span:last-child {
  color: var(--muted-color);
  text-align: right;
}

.list button.active {
  background: var(--accent-color);
  color: #fffaf0;
}

select {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border-color);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.45);
}

.reader-shell {
  display: grid;
  grid-template-rows: auto 1fr auto;
  gap: 18px;
  padding: 24px;
  height: 100%;
  min-height: 0;
  box-sizing: border-box;
  overflow: hidden;
}

body.is-immersive .reader-shell {
  grid-template-rows: 1fr;
  gap: 0;
  padding: 0;
}

.reader-header,
.reader-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.reader-header h1 {
  margin: 0;
  font-size: 32px;
}

body.is-immersive .reader-header h1 {
  font-size: 28px;
}

body.is-immersive .eyebrow {
  display: none;
}

body.is-immersive .reader-header,
body.is-immersive .reader-footer,
body.is-immersive .debug-panel {
  display: none;
}

body.is-immersive .spread-shell {
  height: 100vh;
  min-height: 100vh;
  border-radius: 0;
  border-left: none;
  border-right: none;
  box-shadow: none;
}

body.is-immersive .paper-page {
  padding-top: 24px;
  padding-bottom: 24px;
}

.header-actions,
.nav-group {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.inline-language {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.inline-language span {
  font-size: 13px;
  color: var(--muted-color);
}

.inline-language select {
  width: auto;
  min-width: 116px;
  padding: 8px 10px;
  border-radius: 12px;
}

/* ── 书本双页展开 ── */
.spread-shell {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  min-height: 0;
  border-radius: 20px;
  border: 1px solid var(--border-color);
  box-shadow: 0 22px 50px var(--surface-shadow);
  overflow: hidden;
}

.spread-shell.is-single {
  grid-template-columns: 1fr;
}

.spread-shell.is-single .right-page {
  display: none;
}

.spread-shell.is-scroll-mode {
  grid-template-columns: 1fr;
  border: none;
  box-shadow: none;
  border-radius: 0;
  background: transparent;
}

.spread-shell.is-scroll-mode .right-page {
  display: none;
}

.paper-page {
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding: 28px 32px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.35), transparent 12%),
    var(--surface-color);
  overflow: hidden;
}

/* 左页右侧加书脊阴影，模拟装订感 */
.left-page {
  border-right: 1.5px solid var(--border-color);
  box-shadow: inset -8px 0 18px rgba(0, 0, 0, 0.05);
}

.right-page {
  box-shadow: inset 8px 0 18px rgba(0, 0, 0, 0.05);
}

.spread-shell.is-scroll-mode .paper-page {
  border: 1px solid var(--border-color);
  border-radius: 12px;
  box-shadow: none;
  background: rgba(255, 255, 255, 0.2);
}

.spread-shell.is-scroll-mode .left-page {
  border-right: 1px solid var(--border-color);
  box-shadow: none;
}

.page-title {
  position: relative;
  z-index: 1;
  margin: 0 0 18px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted-color);
}

.page-content {
  position: relative;
  z-index: 1;
  white-space: pre-wrap;
  font-size: var(--font-size);
  line-height: var(--line-height);
  overflow: hidden;
  flex: 1;
  min-height: 0;
}

.page-content.empty {
  color: var(--muted-color);
}

.spread-shell.is-scroll-mode .page-content {
  overflow-y: auto;
  overflow-x: hidden;
}

.page-content.turn-slide-soft {
  animation: turn-slide-soft 220ms ease;
}

.page-content.turn-slide-hard {
  animation: turn-slide-hard 320ms ease;
}

.page-content.turn-fade-soft {
  animation: turn-fade-soft 220ms ease;
}

.page-content.turn-fade-hard {
  animation: turn-fade-hard 360ms ease;
}

@keyframes turn-slide-soft {
  from {
    transform: translateX(10px);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes turn-slide-hard {
  from {
    transform: translateX(24px) scale(0.98);
    opacity: 0;
  }
  to {
    transform: translateX(0) scale(1);
    opacity: 1;
  }
}

@keyframes turn-fade-soft {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes turn-fade-hard {
  0% {
    opacity: 0;
  }
  40% {
    opacity: 0.2;
  }
  100% {
    opacity: 1;
  }
}

.reader-footer label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.settings-card {
  width: min(680px, calc(100vw - 32px));
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.settings-grid label {
  display: grid;
  gap: 6px;
}

.settings-grid label span {
  font-size: 13px;
  color: var(--muted-color);
}

.settings-switch {
  margin-top: 14px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text-color);
}

.settings-switch input {
  margin: 0;
}

.settings-section {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--border-color);
}

.settings-card .file-picker span {
  width: auto;
}

/* Cloud Backup UI Styles */
.status-badge {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  font-size: 14px;
  line-height: 10px;
  text-align: center;
  color: #999;
  font-weight: bold;
  margin-left: 4px;
}

.status-badge[data-status="connected"] {
  color: #4caf50;
}

.status-badge[data-status="authed"] {
  color: #4caf50;
}

.status-badge[data-status="needs-auth"] {
  color: #ff9800;
}

.status-badge[data-status="error"] {
  color: #f44336;
}

#cloud-section .action-row button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.cloud-config {
  display: grid;
  gap: 8px;
  margin-bottom: 8px;
}

.cloud-config-item {
  display: grid;
  gap: 4px;
}

.cloud-config-item span {
  font-size: 12px;
  color: #666;
}

.cloud-config-item input {
  width: 100%;
  border: 1px solid #d7dce4;
  border-radius: 8px;
  padding: 7px 10px;
  font-size: 13px;
  background: #fff;
}

.cloud-config-item input:focus {
  border-color: #7ba8e8;
  outline: none;
  box-shadow: 0 0 0 2px rgba(123, 168, 232, 0.2);
}

.token-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
  align-items: center;
}

.token-row .small-button {
  min-width: 64px;
  text-align: center;
}

.cloud-token-note {
  margin-top: 4px;
  font-size: 12px;
  line-height: 1.5;
}

.cloud-backups-title {
  margin: 8px 0 4px;
  font-size: 0.9em;
}

.cloud-quota {
  margin-top: 8px;
  font-size: 0.85em;
}

#cloud-backups-list {
  max-height: 200px;
  overflow-y: auto;
}

#cloud-backups-list .list-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid #eee;
  font-size: 0.9em;
}

#cloud-backups-list .list-item:last-child {
  border-bottom: none;
}

#cloud-backups-list .backup-info {
  flex: 1;
}

#cloud-backups-list .backup-name {
  font-weight: 500;
  word-break: break-word;
}

#cloud-backups-list .backup-time {
  font-size: 0.85em;
  color: #666;
  margin-top: 2px;
}

#cloud-backups-list .backup-actions {
  display: flex;
  gap: 4px;
  margin-left: 8px;
  white-space: nowrap;
}

#cloud-backups-list .backup-actions button {
  padding: 2px 6px;
  font-size: 0.85em;
  background: #f0f0f0;
  border: 1px solid #ddd;
  border-radius: 3px;
  cursor: pointer;
  transition: background 0.2s;
}

#cloud-backups-list .backup-actions button:hover {
  background: #e0e0e0;
}

.hidden {
  display: none !important;
}

.mode-hint {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--border-color);
  font-size: 12px;
  color: var(--muted-color);
  background: rgba(255, 255, 255, 0.4);
}

.mode-hint.hidden {
  display: none;
}

#debug-toggle.active {
  background: var(--accent-color);
  color: #fffaf0;
}

#immersive-toggle.active {
  background: var(--accent-color);
  color: #fffaf0;
}

.immersive-exit {
  position: fixed;
  top: 14px;
  right: 14px;
  z-index: 30;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.75);
  backdrop-filter: blur(8px);
}

.immersive-exit.hidden {
  display: none;
}

body.is-immersive .immersive-exit.hidden {
  display: inline-flex;
}

.debug-panel {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 20;
  width: min(460px, calc(100vw - 32px));
  max-height: min(50vh, 420px);
  margin: 0;
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  overflow: auto;
  background: rgba(40, 30, 20, 0.9);
  color: #f8ecd8;
  font: 12px/1.4 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  white-space: pre-wrap;
}

.debug-panel.hidden {
  display: none;
}

.overlay {
  position: fixed;
  inset: 0;
  z-index: 25;
  display: grid;
  place-items: center;
  padding: 24px;
  background: rgba(27, 20, 12, 0.42);
  backdrop-filter: blur(8px);
}

.overlay.hidden {
  display: none;
}

.overlay-card {
  width: min(720px, calc(100vw - 32px));
  max-height: calc(100vh - 48px);
  overflow: auto;
  padding: 20px;
  border: 1px solid var(--border-color);
  border-radius: 20px;
  background: var(--surface-color);
  box-shadow: 0 24px 60px var(--surface-shadow);
}

.overlay-head h2 {
  margin: 0;
  font-size: 20px;
}

.shortcut-grid {
  display: grid;
  gap: 10px;
  margin-top: 16px;
}

.shortcut-grid div {
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 12px;
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.22);
}

.shortcut-grid span {
  color: var(--muted-color);
}

#font-size {
  accent-color: var(--accent-color);
}

@media (max-width: 1100px) {
  .app-shell {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
  }

  .side-panel {
    height: auto;
    max-height: 38vh;
    border-right: 0;
    border-bottom: 1px solid var(--border-color);
  }
}

@media (max-width: 820px) {
  .spread-shell {
    grid-template-columns: 1fr;
  }

  .right-page {
    display: none;
  }

  .debug-panel {
    right: 8px;
    bottom: 8px;
    width: calc(100vw - 16px);
    max-height: 45vh;
  }

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