fix(tool): left time condition (#109)

Author: Chocolate1999

docs/tool/off-time/demo.vue

@@ -48,6 +48,6 @@ const cal = () => {
   <pre v-if="start_time">上班时间：{{ start_time }}</pre>
   <pre v-if="end_time">下班时间：{{ end_time }}</pre>
   <pre
-    v-if="leftTime.hour || leftTime.min || leftTime.sec"
+    v-if="leftTime.hour > 0 || leftTime.min > 0 || leftTime.sec > 0"
   >距离下班还有 {{ leftTime.hour }} 时 {{ leftTime.min }} 分 {{ leftTime.sec }} 秒</pre>
 </template>