refine: use icon for currency display toggle

apps/web/src/styles.css

@@ -104,30 +104,21 @@ input:focus-visible {
   gap: 6px;
 }
 
-.currency-display-toggle {
-  height: 32px;
-  display: inline-flex;
-  align-items: stretch;
+.currency-display-button {
+  width: 34px;
+  height: 34px;
+  display: inline-grid;
+  place-items: center;
   border: 1px solid rgba(255, 255, 255, 0.28);
   border-radius: 7px;
-  padding: 2px;
+  padding: 0;
   background: rgba(0, 0, 0, 0.12);
+  color: rgba(255, 255, 255, 0.82);
 }
 
-.currency-display-toggle button {
-  min-width: 32px;
-  border: 0;
-  border-radius: 5px;
-  padding: 0 6px;
-  background: transparent;
-  color: rgba(255, 255, 255, 0.72);
-  font-size: 11px;
-  font-weight: 700;
-}
-
-.currency-display-toggle button.active {
-  background: rgba(255, 255, 255, 0.92);
-  color: #24766d;
+.currency-display-button.active {
+  background: rgba(255, 255, 255, 0.2);
+  color: #ffffff;
 }
 
 .participant-avatars {

apps/web/src/views/LedgerView.vue

@@ -2,6 +2,7 @@
 import { formatCurrencyAmount, type LedgerEntry } from "@cents/domain";
 import {
   BookOpen,
+  ArrowLeftRight,
   ChevronLeft,
   ChevronDown,
   ChevronRight,
@@ -437,10 +438,17 @@ async function shareLedger() {
           <ChevronDown :size="16" />
         </button>
         <div class="header-right-actions">
-          <div class="currency-display-toggle" role="group" aria-label="流水金额显示方式">
-            <button type="button" :class="{ active: showBaseCurrency }" :aria-pressed="showBaseCurrency" @click="showBaseCurrency = true">本币</button>
-            <button type="button" :class="{ active: !showBaseCurrency }" :aria-pressed="!showBaseCurrency" @click="showBaseCurrency = false">原币</button>
-          </div>
+          <button
+            class="currency-display-button"
+            type="button"
+            :class="{ active: showBaseCurrency }"
+            :aria-label="showBaseCurrency ? '当前显示本币，点击显示原币' : '当前显示原币，点击显示本币'"
+            :title="showBaseCurrency ? '当前显示本币，点击切换为原币' : '当前显示原币，点击切换为本币'"
+            :aria-pressed="showBaseCurrency"
+            @click="showBaseCurrency = !showBaseCurrency"
+          >
+            <ArrowLeftRight :size="17" />
+          </button>
           <button v-if="ledgerStore.currentRole === 'owner'" class="icon-button header-icon" type="button" aria-label="更多" title="更多" @click.stop="moreMenuOpen = true">
             <MoreHorizontal :size="21" />
           </button>