fix sidebar width

report of hyparam/hyperparam-cli#124

Author: severo

src/styles/index.css

@@ -66,7 +66,7 @@ main {
   display: flex;
   flex-direction: column;
   height: 100vh;
-  min-width: 48px;
+  width: 48px;
   background-image: linear-gradient(to bottom, #667, #585669);
   box-shadow: 0 0 4px rgba(10, 10, 10, 0.5);
   height: 100vh;