v3: dump edit balances its two columns — the dump itself (preview, refresh, thumbnail, URL or replacement file) on the left, its presentation (title, why, categories, visibility) on the right, actions in a full-width footer bar so both columns end level; "Why?" stretches to absorb a taller preview on desktop

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/App.css

@@ -95,8 +95,8 @@
 .dump-post-header,
 .dump-rich-content,
 .form-page-header,
-.dump-edit-preview,
-.form-page .form,
+.dump-edit-panel,
+.dump-edit-footer,
 .playlist-detail-header,
 .comment-node-inner {
   box-shadow: var(--panel-ring), var(--card-shadow);
@@ -3032,20 +3032,38 @@ body.has-player .chat-fab {
   animation: page-enter 0.2s ease both;
 }
 
+/* The edit form spans the page grid and lays out its own panels: the dump
+   itself (preview, thumbnail, source) beside its presentation (title, why,
+   categories, visibility), with a full-width action bar underneath so both
+   columns end on the same line. Only the header and footer are rounded. */
+.dump-edit-form {
+  display: grid;
+  grid-template-columns: 1fr;
+  gap: inherit;
+}
+
 @media (min-width: 860px) {
-  .form-page--two-col {
+  .form-page--two-col,
+  .dump-edit-form {
     grid-template-columns: 1fr 1fr;
   }
-  .form-page--two-col .form-page-header {
+  .form-page--two-col .form-page-header,
+  .dump-edit-form,
+  .dump-edit-footer {
     grid-column: 1 / -1;
   }
-  .form-page--two-col .dump-edit-preview {
-    border-radius: 0 0 0 var(--radius-xl);
+  /* "Why?" soaks up whatever height the source column adds, so a tall
+     preview doesn't leave a hole under the details. */
+  .dump-edit-panel--details .form-field:has(.mention-textarea-wrap) {
+    flex: 1 1 auto;
   }
-  /* Higher specificity than the generic `.form-page .form` below so the
-     form's bottom-left stays square where it meets the preview. */
-  .form-page.form-page--two-col .form {
-    border-radius: 0 0 var(--radius-xl) 0;
+  .dump-edit-panel--details .mention-textarea-wrap {
+    flex: 1 1 auto;
+    display: flex;
+    flex-direction: column;
+  }
+  .dump-edit-panel--details .mention-textarea-wrap textarea {
+    flex: 1 1 auto;
   }
 }
 
@@ -3074,13 +3092,31 @@ body.has-player .chat-fab {
   word-break: break-word;
 }
 
-.dump-edit-preview {
+.dump-edit-panel {
+  display: flex;
+  flex-direction: column;
+  gap: 1rem;
+  min-width: 0;
   padding: 1.25rem;
   background: var(--color-surface);
+}
+
+.dump-edit-preview {
   overflow: hidden;
+}
+
+.dump-edit-footer {
+  padding: 0.875rem 1.25rem;
+  background: var(--color-surface);
   border-radius: 0 0 var(--radius-xl) var(--radius-xl);
 }
 
+.dump-edit-footer .form-actions {
+  padding-top: 0;
+  border-top: 0;
+  margin-top: 0;
+}
+
 .dump-edit-refresh {
   margin-top: 0.75rem;
 }
@@ -3097,12 +3133,6 @@ body.has-player .chat-fab {
   gap: 0.75rem;
 }
 
-.form-page .form {
-  background: var(--color-surface);
-  border-radius: 0 0 var(--radius-xl) var(--radius-xl);
-  padding: 1.25rem;
-}
-
 .form-actions {
   display: flex;
   align-items: center;

src/pages/DumpEdit.tsx

@@ -214,41 +214,42 @@ export function DumpEdit() {
           <h1 className="form-page-title">{dump.title}</h1>
         </div>
 
-        <div className="dump-edit-preview">
-          {dump.kind === "file"
-            ? <FilePreview dump={dump} />
-            : dump.richContent
-            ? <RichContentCard richContent={dump.richContent} />
-            : dump.url && (
-              <a
-                href={dump.url}
-                target="_blank"
-                rel="noopener noreferrer"
-                className="dump-url-link"
-              >
-                {dump.url}
-              </a>
-            )}
-          {dump.kind === "url" && (
-            <button
-              type="button"
-              className="btn-secondary dump-edit-refresh"
-              onClick={handleRefreshMetadata}
-              disabled={refreshing}
-            >
-              {refreshing
-                ? <Trans>Refreshing…</Trans>
-                : <Trans>Refresh metadata</Trans>}
-            </button>
-          )}
-          {refreshError && (
-            <p className="dump-edit-refresh-error">{refreshError}</p>
-          )}
-        </div>
-
         <DumpEditForm
           key={dump.id}
           dump={dump}
+          preview={
+            <div className="dump-edit-preview">
+              {dump.kind === "file"
+                ? <FilePreview dump={dump} />
+                : dump.richContent
+                ? <RichContentCard richContent={dump.richContent} />
+                : dump.url && (
+                  <a
+                    href={dump.url}
+                    target="_blank"
+                    rel="noopener noreferrer"
+                    className="dump-url-link"
+                  >
+                    {dump.url}
+                  </a>
+                )}
+              {dump.kind === "url" && (
+                <button
+                  type="button"
+                  className="btn-secondary dump-edit-refresh"
+                  onClick={handleRefreshMetadata}
+                  disabled={refreshing}
+                >
+                  {refreshing
+                    ? <Trans>Refreshing…</Trans>
+                    : <Trans>Refresh metadata</Trans>}
+                </button>
+              )}
+              {refreshError && (
+                <p className="dump-edit-refresh-error">{refreshError}</p>
+              )}
+            </div>
+          }
           currentThumbnailSrc={currentThumbnailSrc}
           thumbUploading={thumbUploading}
           onThumbnailChange={handleThumbnailChange}
@@ -272,6 +273,7 @@ export function DumpEdit() {
 
 interface DumpEditFormProps {
   dump: Dump;
+  preview: React.ReactNode;
   currentThumbnailSrc: string | null;
   thumbUploading: boolean;
   onThumbnailChange: (file: File) => void;
@@ -290,6 +292,7 @@ interface EditValues {
 
 function DumpEditForm({
   dump,
+  preview,
   currentThumbnailSrc,
   thumbUploading,
   onThumbnailChange,
@@ -367,111 +370,123 @@ function DumpEditForm({
 
   return (
     <FormProvider {...form}>
-      <form className="form" onSubmit={onSubmit}>
-        <FormError title={t`Could not save`} />
+      <form className="form dump-edit-form" onSubmit={onSubmit}>
+        {
+          /* Left: the dumped thing itself — what it looks like and where it
+            comes from. Right: how it's presented and shared. */
+        }
+        <div className="dump-edit-panel dump-edit-panel--source">
+          {preview}
 
-        <div className="form-field">
-          <span className="form-label">
-            <Trans>Thumbnail</Trans>
-          </span>
-          <div className="dump-edit-thumbnail-row">
-            <ImagePicker
-              src={currentThumbnailSrc}
-              size={64}
-              onChange={onThumbnailChange}
-              uploading={thumbUploading}
-            />
-            {dump.thumbnailMime && (
-              <button
-                type="button"
-                className="btn-border"
-                onClick={onThumbnailReset}
-                disabled={thumbUploading}
-              >
-                <Trans>Reset to default</Trans>
-              </button>
-            )}
+          <div className="form-field">
+            <span className="form-label">
+              <Trans>Thumbnail</Trans>
+            </span>
+            <div className="dump-edit-thumbnail-row">
+              <ImagePicker
+                src={currentThumbnailSrc}
+                size={64}
+                onChange={onThumbnailChange}
+                uploading={thumbUploading}
+              />
+              {dump.thumbnailMime && (
+                <button
+                  type="button"
+                  className="btn-border"
+                  onClick={onThumbnailReset}
+                  disabled={thumbUploading}
+                >
+                  <Trans>Reset to default</Trans>
+                </button>
+              )}
+            </div>
           </div>
+
+          {dump.kind === "url"
+            ? (
+              <TextField<EditValues>
+                name="url"
+                type="url"
+                label={t`URL`}
+                placeholder="https://..."
+                rules={{ required: true }}
+              />
+            )
+            : (
+              <div className="form-field">
+                <span className="form-label">
+                  <Trans>Replace file</Trans>
+                </span>
+                <p className="dump-file-notice">
+                  <strong>{dump.fileName}</strong>
+                  {dump.fileSize != null && ` — ${formatBytes(dump.fileSize)}`}
+                </p>
+                <FileField<EditValues>
+                  name="newFile"
+                  hint={t`Drop a replacement here`}
+                  showLimit={false}
+                />
+              </div>
+            )}
         </div>
 
-        <TextField<EditValues>
-          name="title"
-          label={t`Title`}
-          labelAction={metaTitle
-            ? (
-              <button
-                type="button"
-                className="form-label-action"
-                onClick={() =>
-                  form.setValue("title", metaTitle, { shouldDirty: true })}
-                disabled={currentTitle.trim() === metaTitle}
-              >
-                <Trans>Reset to default</Trans>
-              </button>
-            )
-            : undefined}
-          maxLength={VALIDATION.DUMP_TITLE_MAX}
-          rules={{ required: true }}
-        />
+        <div className="dump-edit-panel dump-edit-panel--details">
+          <FormError title={t`Could not save`} />
 
-        {dump.kind === "url"
-          ? (
-            <TextField<EditValues>
-              name="url"
-              type="url"
-              label={t`URL`}
-              placeholder="https://..."
-              rules={{ required: true }}
-            />
-          )
-          : (
-            <div className="form-field">
-              <span className="form-label">
-                <Trans>Replace file</Trans>
-              </span>
-              <p className="dump-file-notice">
-                <strong>{dump.fileName}</strong>
-                {dump.fileSize != null && ` — ${formatBytes(dump.fileSize)}`}
-              </p>
-              <FileField<EditValues>
-                name="newFile"
-                hint={t`Drop a replacement here`}
-                showLimit={false}
-              />
+          <TextField<EditValues>
+            name="title"
+            label={t`Title`}
+            labelAction={metaTitle
+              ? (
+                <button
+                  type="button"
+                  className="form-label-action"
+                  onClick={() =>
+                    form.setValue("title", metaTitle, { shouldDirty: true })}
+                  disabled={currentTitle.trim() === metaTitle}
+                >
+                  <Trans>Reset to default</Trans>
+                </button>
+              )
+              : undefined}
+            maxLength={VALIDATION.DUMP_TITLE_MAX}
+            rules={{ required: true }}
+          />
+
+          <RichTextField<EditValues>
+            name="comment"
+            label={t`Why?`}
+            placeholder={t`What makes it worth it?`}
+            rows={3}
+            maxLength={VALIDATION.DUMP_COMMENT_MAX}
+            rules={{ maxLength: VALIDATION.DUMP_COMMENT_MAX }}
+          />
+
+          <CategorySelect
+            selected={selectedCategoryIds}
+            onToggle={toggleCategory}
+          />
+
+          <VisibilityToggle<EditValues> name="isPublic" />
+        </div>
+
+        <div className="dump-edit-footer">
+          <div className="form-actions">
+            <button
+              type="button"
+              onClick={onRequestDelete}
+              className="btn-danger"
+            >
+              <Trans>Delete dump</Trans>
+            </button>
+            <div className="form-actions-right">
+              <Link to={dumpUrl(dump)} className="form-cancel">
+                <Trans>Cancel</Trans>
+              </Link>
+              <SubmitButton>
+                <Trans>Save</Trans>
+              </SubmitButton>
             </div>
-          )}
-
-        <RichTextField<EditValues>
-          name="comment"
-          label={t`Why?`}
-          placeholder={t`What makes it worth it?`}
-          rows={3}
-          maxLength={VALIDATION.DUMP_COMMENT_MAX}
-          rules={{ maxLength: VALIDATION.DUMP_COMMENT_MAX }}
-        />
-
-        <CategorySelect
-          selected={selectedCategoryIds}
-          onToggle={toggleCategory}
-        />
-
-        <VisibilityToggle<EditValues> name="isPublic" />
-
-        <div className="form-actions">
-          <button
-            type="button"
-            onClick={onRequestDelete}
-            className="btn-danger"
-          >
-            <Trans>Delete dump</Trans>
-          </button>
-          <div className="form-actions-right">
-            <Link to={dumpUrl(dump)} className="form-cancel">
-              <Trans>Cancel</Trans>
-            </Link>
-            <SubmitButton>
-              <Trans>Save</Trans>
-            </SubmitButton>
           </div>
         </div>
       </form>