/* React mounts into #root; display:contents removes it from the flex chain */
#root { display: contents; }

/* Reset body to a layout container (book-page.css targets body for page content) */
html, body {
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  padding: 0;
  max-width: unset;
  margin: 0;
  background-image: none;
}

/* ── App header ── */
header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 20px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border-bright);
  flex-shrink: 0;
}

.logo {
  font-family: var(--font-display);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--teal);
}

.toolbar {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* ── Prev / Next buttons ── */
.tab {
  background: var(--surface3);
  border: 1px solid var(--border-bright);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  padding: 5px 14px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}

.tab:hover:not(:disabled) {
  background: var(--surface);
  color: var(--teal);
  border-color: var(--teal-dim);
}

.tab:disabled {
  opacity: 0.35;
  cursor: default;
}

#layout {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ── Sidebar ── */
#sidebar {
  width: 270px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border-right: 1px solid var(--border-bright);
  overflow: hidden;
}

#sidebar-header {
  padding: 14px 16px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border-bright);
  flex-shrink: 0;
}

#sidebar-header p {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-dim);
  margin-top: 4px;
}

#page-list {
  flex: 1;
  overflow-y: auto;
  list-style: none;
  padding: 4px 0;
}

#page-list li button {
  width: 100%;
  text-align: left;
  padding: 6px 14px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-dim);
  font-family: var(--font-body);
  font-size: 0.88rem;
  display: flex;
  gap: 10px;
  align-items: baseline;
  transition: background 0.15s, color 0.15s;
}

#page-list li button:hover {
  background: var(--surface2);
  color: var(--text);
}

#page-list li.active button {
  background: var(--surface3);
  color: var(--teal);
}

.page-num {
  flex-shrink: 0;
  min-width: 24px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--border-bright);
}

li.active .page-num {
  color: var(--teal-dim);
}

/* ── Main area ── */
#main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* ── Nav bar ── */
#nav {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 20px;
  background: var(--surface);
  border-bottom: 1px solid var(--border-bright);
  flex-shrink: 0;
}

#page-title {
  flex: 1;
  text-align: center;
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#page-indicator {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dim);
  white-space: nowrap;
}

/* ── Scrollable content ── */
#content {
  flex: 1;
  overflow-y: auto;
  background: var(--bg);
  background-image:
    radial-gradient(ellipse at 20% 10%, rgba(78,205,196,.04) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 90%, rgba(201,168,76,.04) 0%, transparent 50%);
}

/* ── Page sections ── */
.page-section {
  max-width: 860px;
  margin: 0 auto;
  padding: 32px;
  border-bottom: 1px solid var(--border);
}

.page-section:last-child {
  border-bottom: none;
  min-height: calc(100vh - 80px);
}

/* Override book-page.css header rule inside sections */
.page-section header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.8em;
  margin-bottom: 1.4em;
}