feat: add loading animation

static/src/App.vue

@@ -1,12 +1,39 @@
 <template>
   <AppShell :download-file="downloadFile" :download-folder="downloadFolder">
-    <div
-      v-if="!isConnected && messages.length === 0"
-      class="app-loading-state"
-      style="text-align: center; padding: 50px;"
-    >
-      <h2>正在连接服务器...</h2>
-      <p>如果长时间无响应，请刷新页面</p>
+    <div v-if="!isConnected && messages.length === 0" class="app-loading-state">
+      <div class="loading-animation" aria-hidden="true">
+        <!-- From Uiverse.io by Nawsome -->
+        <div class="boxes">
+          <div class="box">
+            <div></div>
+            <div></div>
+            <div></div>
+            <div></div>
+          </div>
+          <div class="box">
+            <div></div>
+            <div></div>
+            <div></div>
+            <div></div>
+          </div>
+          <div class="box">
+            <div></div>
+            <div></div>
+            <div></div>
+            <div></div>
+          </div>
+          <div class="box">
+            <div></div>
+            <div></div>
+            <div></div>
+            <div></div>
+          </div>
+        </div>
+      </div>
+      <div class="loading-copy">
+        <h2>加载中...</h2>
+        <p>正在连接服务器，请稍候</p>
+      </div>
     </div>
 
     <template v-else>

static/src/styles/components/overlays/_overlays.scss

@@ -548,3 +548,170 @@
     border-left: 1px solid var(--claude-border);
     padding: 0 0 0 0;
 }
+.app-loading-state {
+    min-height: calc(var(--app-viewport, 100vh) - 160px);
+    padding: 60px 20px;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    gap: 28px;
+    text-align: center;
+    color: var(--claude-text);
+}
+
+.loading-animation {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+}
+
+.loading-copy {
+    margin-top: 48px;
+}
+.loading-copy h2 {
+    margin: 0;
+    font-size: 24px;
+    font-weight: 600;
+}
+
+.loading-copy p {
+    margin: 6px 0 0;
+    color: var(--claude-text-secondary);
+}
+
+.boxes {
+    --size: 34px;
+    --duration: 900ms;
+    --box-primary: var(--claude-accent);
+    --box-secondary: var(--claude-accent-strong, #d07b4c);
+    --box-tertiary: #f8d7c0;
+    height: calc(var(--size) * 2);
+    width: calc(var(--size) * 3);
+    position: relative;
+    transform-style: preserve-3d;
+    transform-origin: 50% 50%;
+    margin-top: calc(var(--size) * -1.5);
+    transform: rotateX(60deg) rotateZ(45deg) rotateY(0deg) translateZ(0px);
+}
+
+.boxes .box {
+    width: var(--size);
+    height: var(--size);
+    top: 0;
+    left: 0;
+    position: absolute;
+    transform-style: preserve-3d;
+}
+
+.boxes .box:nth-child(1) {
+    transform: translate(100%, 0);
+    animation: box1 var(--duration) linear infinite;
+}
+
+.boxes .box:nth-child(2) {
+    transform: translate(0, 100%);
+    animation: box2 var(--duration) linear infinite;
+}
+
+.boxes .box:nth-child(3) {
+    transform: translate(100%, 100%);
+    animation: box3 var(--duration) linear infinite;
+}
+
+.boxes .box:nth-child(4) {
+    transform: translate(200%, 0);
+    animation: box4 var(--duration) linear infinite;
+}
+
+.boxes .box > div {
+    --background: var(--box-primary);
+    --top: auto;
+    --right: auto;
+    --bottom: auto;
+    --left: auto;
+    --translateZ: calc(var(--size) / 2);
+    --rotateY: 0deg;
+    --rotateX: 0deg;
+    position: absolute;
+    width: 100%;
+    height: 100%;
+    background: var(--background);
+    top: var(--top);
+    right: var(--right);
+    bottom: var(--bottom);
+    left: var(--left);
+    border-radius: 6px;
+    transform: rotateY(var(--rotateY)) rotateX(var(--rotateX)) translateZ(var(--translateZ));
+}
+
+.boxes .box > div:nth-child(1) {
+    --top: 0;
+    --left: 0;
+}
+
+.boxes .box > div:nth-child(2) {
+    --background: var(--box-secondary);
+    --right: 0;
+    --rotateY: 90deg;
+}
+
+.boxes .box > div:nth-child(3) {
+    --background: var(--box-tertiary);
+    --rotateX: -90deg;
+}
+
+.boxes .box > div:nth-child(4) {
+    --background: rgba(255, 255, 255, 0.95);
+    --top: 0;
+    --left: 0;
+    --translateZ: calc(var(--size) * 3 * -1);
+}
+
+@keyframes box1 {
+    0%, 50% {
+        transform: translate(100%, 0);
+    }
+
+    100% {
+        transform: translate(200%, 0);
+    }
+}
+
+@keyframes box2 {
+    0% {
+        transform: translate(0, 100%);
+    }
+
+    50% {
+        transform: translate(0, 0);
+    }
+
+    100% {
+        transform: translate(100%, 0);
+    }
+}
+
+@keyframes box3 {
+    0%, 50% {
+        transform: translate(100%, 100%);
+    }
+
+    100% {
+        transform: translate(0, 100%);
+    }
+}
+
+@keyframes box4 {
+    0% {
+        transform: translate(200%, 0);
+    }
+
+    50% {
+        transform: translate(200%, 100%);
+    }
+
+    100% {
+        transform: translate(100%, 100%);
+    }
+}