Fix calendar popover width for mobile (#146)

Author: melissawm

napari_sphinx_theme/static/css/napari-sphinx-theme.css

@@ -1053,14 +1053,31 @@ div.admonition.note>.admonition-title::after {
     margin: auto;
     padding: 0;
     border: 1px solid #888;
-    width: 20%;
     box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
     -webkit-animation-name: animatetop;
     -webkit-animation-duration: 0.4s;
     animation-name: animatetop;
     animation-duration: 0.4s
 }
 
+/* Modal Content */
+.modal-content {
+    width: 30%;
+}
+
+@media (max-width: 780px) {
+    .modal-content {
+        width: 50%;
+    }
+}
+
+@media (max-width: 495px) {
+    .modal-content {
+        width: 80%;
+    }
+}
+
+
 /* Add Animation */
 @-webkit-keyframes animatetop {
     from {