diff --git a/web/src/assets/styles/app.css b/web/src/assets/styles/app.css
index f6d3b79..1fcc05f 100644
--- a/web/src/assets/styles/app.css
+++ b/web/src/assets/styles/app.css
@@ -15,6 +15,7 @@
 }
 
 .app {
+  height: var(--desktop-stage-height, 100dvh);
   min-height: var(--desktop-stage-height, 100dvh);
   display: grid;
   grid-template-columns: 220px minmax(0, 1fr);
@@ -82,12 +83,16 @@
   font-weight: 700;
 }
 
-.main { min-width: 0; display: grid; grid-template-rows: auto auto minmax(0, 1fr); }
+.main { min-width: 0; min-height: 0; display: grid; grid-template-rows: auto auto minmax(0, 1fr); }
 .main.overview-main {
+  height: var(--desktop-stage-height, 100dvh);
   grid-template-rows: auto minmax(0, 1fr);
+  overflow: hidden;
 }
 .main.workbench-main {
+  height: var(--desktop-stage-height, 100dvh);
   grid-template-rows: auto minmax(0, 1fr);
+  overflow: hidden;
 }
 .main.chat-main {
   height: var(--desktop-stage-height, 100dvh);
@@ -110,7 +115,7 @@
 .main.audit-detail-main {
   grid-template-rows: minmax(0, 1fr);
 }
-.workarea { overflow: auto; padding: 24px; }
+.workarea { min-height: 0; overflow: auto; padding: 24px; }
 .workarea.chat-workarea {
   min-height: 0;
   overflow: hidden;
diff --git a/web/src/assets/styles/global.css b/web/src/assets/styles/global.css
index 51e49c1..6a09aa6 100644
--- a/web/src/assets/styles/global.css
+++ b/web/src/assets/styles/global.css
@@ -27,6 +27,8 @@
   --desktop-ui-inverse-scale: 1;
   --desktop-stage-width: 100vw;
   --desktop-stage-height: 100dvh;
+  --desktop-viewport-width: 1440;
+  --desktop-viewport-height: 900;
   font-family: "LXGW WenKai", Inter, "SF Pro Display", "PingFang SC", sans-serif;
 }