diff --git a/src/styles.css b/src/styles.css
index bdf0e4d..5a6f61a 100644
--- a/src/styles.css
+++ b/src/styles.css
@@ -22,12 +22,15 @@
   color: var(--fg);
 }
 
+*, *::before, *::after { box-sizing: border-box; }
+
 html, body {
   margin: 0;
   padding: 0;
   width: 100%;
   height: 100%;
   background: transparent; /* honor Tauri transparent:true */
+  overflow: hidden;        /* viewport never scrolls; sections handle their own */
   user-select: none;
   -webkit-user-select: none;
 }