iter(g101): 新增锚点导航组件 anchor

packages/skin/ui/ui.css

@@ -3611,3 +3611,67 @@ button.ua-step-dot:hover {
 .ua-space.is-block {
   width: 100%;
 }
+
+/* —— 锚点导航 —— */
+.ua-anchor {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+  padding-left: var(--ua-space-3);
+}
+.ua-anchor::before {
+  content: '';
+  position: absolute;
+  left: 0;
+  top: 0;
+  bottom: 0;
+  width: 2px;
+  background: var(--ua-color-border);
+  border-radius: 1px;
+}
+.ua-anchor-link {
+  position: relative;
+  padding: var(--ua-space-1) var(--ua-space-2);
+  border-radius: var(--ua-radius-sm);
+  color: var(--ua-color-text-muted);
+  font-size: var(--ua-font-size-md);
+  text-decoration: none;
+  transition: color 0.15s, background-color 0.15s, transform 0.15s;
+}
+.ua-anchor-link:hover {
+  color: var(--ua-color-text);
+  background: color-mix(in srgb, var(--ua-color-accent) 6%, transparent);
+  transform: translateX(2px);
+}
+.ua-anchor-link.is-active {
+  color: var(--ua-color-text);
+  background: color-mix(in srgb, var(--ua-color-accent) 10%, transparent);
+}
+.ua-anchor-link.is-active::before {
+  content: '';
+  position: absolute;
+  left: calc(-1 * var(--ua-space-3));
+  top: 50%;
+  width: 2px;
+  height: 70%;
+  transform: translateY(-50%);
+  background: var(--ua-color-accent);
+  border-radius: 1px;
+}
+.ua-anchor-link.is-disabled {
+  opacity: 0.45;
+  pointer-events: none;
+}
+.ua-anchor-link:focus-visible {
+  outline: 2px solid var(--ua-color-accent);
+  outline-offset: 2px;
+}
+@media (prefers-reduced-motion: reduce) {
+  .ua-anchor-link {
+    transition: none;
+  }
+  .ua-anchor-link:hover {
+    transform: none;
+  }
+}