iter(g160): 滑块支持双滑块区间

packages/skin/ui/ui.css

@@ -826,6 +826,46 @@ body.ua-col-resizing {
   font-variant-numeric: tabular-nums;
   text-align: right;
 }
+.ua-slider-range {
+  position: relative;
+  flex: 1;
+  display: flex;
+  align-items: center;
+  height: 20px;
+}
+.ua-slider-rail {
+  position: absolute;
+  left: 0;
+  right: 0;
+  height: 4px;
+  border-radius: var(--ua-radius-sm);
+  background: color-mix(in srgb, var(--ua-color-border) 70%, transparent);
+}
+.ua-slider-seg {
+  position: absolute;
+  height: 4px;
+  border-radius: var(--ua-radius-sm);
+  background: var(--ua-color-accent);
+  transition: left 0.15s, width 0.15s;
+}
+.ua-slider-range .ua-slider-input {
+  position: absolute;
+  inset: 0;
+  width: 100%;
+  height: 100%;
+  margin: 0;
+  background: none;
+  pointer-events: none; /* 轨道不吃事件，只有拇指可拖，避免上下两条互相遮挡 */
+}
+.ua-slider-range .ua-slider-input::-webkit-slider-thumb {
+  pointer-events: auto;
+}
+.ua-slider-range .ua-slider-input::-moz-range-thumb {
+  pointer-events: auto;
+}
+@media (prefers-reduced-motion: reduce) {
+  .ua-slider-seg { transition: none; }
+}
 
 /* —— 多行输入 —— */
 .ua-textarea {