Front-end: On book page, click on cover to show/add image

Closes #1009

bookwyrm/static/css/bookwyrm.css

@@ -30,6 +30,9 @@ button {
 
     /* Corrects inability to style clickable `input` types in iOS */
     -webkit-appearance: none;
+
+    /* Generalizes pointer cursor */
+    cursor: pointer;
 }
 
 button::-moz-focus-inner {
@@ -64,6 +67,14 @@ button::-moz-focus-inner {
     overflow-x: auto;
 }
 
+.modal-card {
+    pointer-events: none;
+}
+
+.modal-card > * {
+    pointer-events: all;
+}
+
 /* stylelint-disable no-descending-specificity */
 .modal-card:focus {
     outline-style: auto;
@@ -148,6 +159,16 @@ button::-moz-focus-inner {
     display: inline !important;
 }
 
+img.is-fit-cover {
+    object-fit: cover;
+    object-position: center;
+}
+
+img.is-fit-contain {
+    object-fit: contain;
+    object-position: center;
+}
+
 /** File input styles
  ******************************************************************************/
 
@@ -429,6 +450,8 @@ details.dropdown .dropdown-menu a:focus-visible {
     display: flex;
     align-items: center;
     justify-content: center;
+    flex-direction: column;
+    gap: 1em;
     white-space: initial;
     text-align: center;
 }