Preview style updates

static/style.css

   background: var(--background);
   color: var(--foreground);
   font-family: VerilySerifMono, monospace;
-  font-size: 14px;
+  font-size: 16px;
   line-height: 1.4;
 }
 
 
 .form__textarea,
 .form__text-field {
-  border: 2px solid var(--foreground);
+  border: 2px solid var(--dark-accent);
   font-family: monospace;
-  font-size: 14px;
+  font-size: 16px;
+  line-height: 1.4em;
   padding: 0.25em;
   width: 100%;
 }
 
 .form__textarea {
-  height: 200px;
+  height: 500px;
+  padding: 0.5em;
   resize: vertical;
 }
 
 }
 
 .post__heading {
-  background: white;
+  background: var(--white);
   border: 1px solid var(--dark-accent);
   font-size: 16px;
   padding: 0.5em;
   padding: 0.5em;
 }
 
+#preview p,
 .post__body p {
   margin: 1em 0;
 }
 
+#preview pre,
 .post__body pre {
   background: var(--off-white);
   border: 1px solid var(--dark-accent);