feat(ui): titlebar export menu and book-setup access

src/styles/app.css

@@ -621,3 +621,153 @@ button {
   text-align: center;
   padding: 44px 0;
 }
+
+.overlay {
+  position: fixed;
+  inset: 0;
+  z-index: 20;
+  background: rgba(35, 32, 27, 0.28);
+  backdrop-filter: blur(2px);
+  display: grid;
+  place-items: center;
+  padding: 40px;
+}
+
+.panel {
+  width: 480px;
+  max-width: 100%;
+  max-height: 100%;
+  display: flex;
+  flex-direction: column;
+  background: var(--paper);
+  border: 1px solid var(--line);
+  border-radius: var(--r-lg);
+  box-shadow: var(--shadow-pop);
+  overflow: hidden;
+}
+
+.panel-head {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 16px 14px 16px 22px;
+  border-bottom: 1px solid var(--line);
+}
+
+.panel-head h2 {
+  margin: 0;
+  font-family: var(--font-book);
+  font-weight: 500;
+  font-size: 18px;
+}
+
+.panel-body {
+  display: flex;
+  flex-direction: column;
+  gap: 15px;
+  padding: 20px 22px 24px;
+  overflow-y: auto;
+}
+
+.field {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.field-label {
+  font-family: var(--font-ui);
+  font-size: var(--t-1);
+  font-weight: 600;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+  color: var(--ink-faint);
+}
+
+.field input,
+.field select {
+  font-family: var(--font-ui);
+  font-size: var(--t-4);
+  color: var(--ink);
+  background: var(--raised);
+  border: 1px solid var(--line-strong);
+  border-radius: var(--r-sm);
+  padding: 9px 11px;
+}
+
+.field input:focus,
+.field select:focus {
+  outline: none;
+  border-color: var(--accent);
+}
+
+.field-row {
+  display: flex;
+  gap: 14px;
+}
+
+.field-row .field {
+  flex: 1;
+}
+
+.check {
+  display: flex;
+  align-items: center;
+  gap: 9px;
+  font-family: var(--font-ui);
+  font-size: var(--t-3);
+  color: var(--ink-soft);
+}
+
+.check input {
+  width: 15px;
+  height: 15px;
+  accent-color: var(--accent);
+}
+
+.doc-title {
+  cursor: pointer;
+}
+
+.doc-title:hover {
+  color: var(--ink);
+}
+
+.menu-wrap {
+  position: relative;
+}
+
+.menu-backdrop {
+  position: fixed;
+  inset: 0;
+  z-index: 25;
+}
+
+.menu {
+  position: absolute;
+  top: 36px;
+  right: 0;
+  z-index: 30;
+  min-width: 156px;
+  display: flex;
+  flex-direction: column;
+  padding: 5px;
+  background: var(--paper);
+  border: 1px solid var(--line);
+  border-radius: var(--r-md);
+  box-shadow: var(--shadow-pop);
+}
+
+.menu button {
+  text-align: left;
+  padding: 8px 11px;
+  border-radius: var(--r-sm);
+  font-family: var(--font-ui);
+  font-size: var(--t-3);
+  color: var(--ink-soft);
+}
+
+.menu button:hover {
+  background: var(--accent-wash);
+  color: var(--ink);
+}