diff --git a/src/index.css b/src/index.css
index f0f72ef..17f3668 100644
--- a/src/index.css
+++ b/src/index.css
@@ -53,12 +53,17 @@ body::before {
 
 /* ── Header ── */
 header {
+  position: sticky;
+  top: 0;
+  z-index: 100;
   display: flex;
   align-items: center;
   justify-content: space-between;
   padding: 22px 0 18px;
+  background: var(--bg);
   border-bottom: 1px solid var(--border);
   margin-bottom: 28px;
+  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
 }
 .logo { display: flex; align-items: center; gap: 10px; }
 .logo-mark {