diff --git a/css/index.css b/css/index.css
index 8005b74..1879eda 100644
--- a/css/index.css
+++ b/css/index.css
@@ -1,3 +1,6 @@
+:root {
+  --main-color: #3498db;
+}
 .header-box {
   width: 100%;
   height: 130px;
diff --git a/css/index.less b/css/index.less
index 64e8da1..3e76ce0 100644
--- a/css/index.less
+++ b/css/index.less
@@ -1,3 +1,7 @@
+:root {
+    --main-color: #3498db;
+}
+
 .header-box {
     width: 100%;
     height: 130px;