resolves #256 disables edit-container button when no container is present

resolve lint errors

review changes

src/css/popup.css

@@ -45,6 +45,7 @@ body {
   --small-text-size: 0.833rem; /* 10px */
   --small-radius: 3px;
   --icon-button-size: calc(calc(var(--block-line-separation-size) * 2) + 1.66rem); /* 20px */
+  --inactive-opacity: 0.3;
 }
 
 @media (min-resolution: 1dppx) {
@@ -578,6 +579,11 @@ span ~ .panel-header-text {
   max-inline-size: 204px;
 }
 
+.disable-edit-containers {
+  opacity: var(--inactive-opacity);
+  pointer-events: none;
+}
+
 .userContext-wrapper {
   align-items: center;
   display: flex;