fix: handle duplicate file hash on re-import and improve alert colors

- importedFileService now upserts: if file hash already exists for a
  source (e.g. from a previous failed import), it updates the existing
  record instead of hitting the UNIQUE constraint.
- Replaced Tailwind amber/red/emerald colors with the app's CSS
  variables (--negative, --positive, --accent) for proper contrast
  on the cream background theme.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/import/DuplicateCheckPanel.tsx

@@ -25,13 +25,13 @@ export default function DuplicateCheckPanel({
 
       {/* File-level duplicate */}
       {result.fileAlreadyImported && (
-        <div className="flex items-start gap-3 p-4 rounded-xl bg-amber-50 dark:bg-amber-950/20 border border-amber-200 dark:border-amber-800">
-          <FileWarning size={20} className="text-amber-500 shrink-0 mt-0.5" />
+        <div className="flex items-start gap-3 p-4 rounded-xl bg-[var(--card)] border-2 border-[var(--accent)]">
+          <FileWarning size={20} className="text-[var(--accent)] shrink-0 mt-0.5" />
           <div>
-            <p className="text-sm font-medium text-amber-800 dark:text-amber-200">
+            <p className="text-sm font-medium text-[var(--foreground)]">
               {t("import.duplicates.fileAlreadyImported")}
             </p>
-            <p className="text-xs text-amber-600 dark:text-amber-400 mt-1">
+            <p className="text-xs text-[var(--muted-foreground)] mt-1">
               {t("import.duplicates.fileAlreadyImportedDesc")}
             </p>
           </div>
@@ -41,18 +41,18 @@ export default function DuplicateCheckPanel({
       {/* Row-level duplicates */}
       {result.duplicateRows.length > 0 ? (
         <div>
-          <div className="flex items-start gap-3 p-4 rounded-xl bg-amber-50 dark:bg-amber-950/20 border border-amber-200 dark:border-amber-800 mb-4">
+          <div className="flex items-start gap-3 p-4 rounded-xl bg-[var(--card)] border-2 border-[var(--accent)] mb-4">
             <AlertTriangle
               size={20}
-              className="text-amber-500 shrink-0 mt-0.5"
+              className="text-[var(--accent)] shrink-0 mt-0.5"
             />
             <div>
-              <p className="text-sm font-medium text-amber-800 dark:text-amber-200">
+              <p className="text-sm font-medium text-[var(--foreground)]">
                 {t("import.duplicates.rowsFound", {
                   count: result.duplicateRows.length,
                 })}
               </p>
-              <p className="text-xs text-amber-600 dark:text-amber-400 mt-1">
+              <p className="text-xs text-[var(--muted-foreground)] mt-1">
                 {t("import.duplicates.rowsFoundDesc")}
               </p>
             </div>
@@ -105,7 +105,7 @@ export default function DuplicateCheckPanel({
                 {result.duplicateRows.map((row) => (
                   <tr
                     key={row.rowIndex}
-                    className="bg-amber-50/50 dark:bg-amber-950/10"
+                    className="bg-[var(--muted)]"
                   >
                     <td className="px-3 py-2 text-[var(--muted-foreground)]">
                       {row.rowIndex + 1}
@@ -125,9 +125,9 @@ export default function DuplicateCheckPanel({
         </div>
       ) : (
         !result.fileAlreadyImported && (
-          <div className="flex items-center gap-3 p-4 rounded-xl bg-emerald-50 dark:bg-emerald-950/20 border border-emerald-200 dark:border-emerald-800">
-            <CheckCircle size={20} className="text-emerald-500" />
-            <p className="text-sm font-medium text-emerald-800 dark:text-emerald-200">
+          <div className="flex items-center gap-3 p-4 rounded-xl bg-[var(--card)] border-2 border-[var(--positive)]">
+            <CheckCircle size={20} className="text-[var(--positive)]" />
+            <p className="text-sm font-medium text-[var(--foreground)]">
               {t("import.duplicates.noneFound")}
             </p>
           </div>

src/components/import/FilePreviewTable.tsx

@@ -32,7 +32,7 @@ export default function FilePreviewTable({
             {t("import.preview.rowCount", { count: rows.length })}
           </span>
           {errorCount > 0 && (
-            <span className="flex items-center gap-1 text-red-500">
+            <span className="flex items-center gap-1 text-[var(--negative)]">
               <AlertCircle size={14} />
               {t("import.preview.errorCount", { count: errorCount })}
             </span>
@@ -67,7 +67,7 @@ export default function FilePreviewTable({
                 key={row.rowIndex}
                 className={
                   row.error
-                    ? "bg-red-50 dark:bg-red-950/20"
+                    ? "bg-[color-mix(in_srgb,var(--negative)_10%,var(--card))]"
                     : "hover:bg-[var(--muted)]"
                 }
               >
@@ -76,7 +76,7 @@ export default function FilePreviewTable({
                 </td>
                 <td className="px-3 py-2">
                   {row.parsed?.date || (
-                    <span className="text-red-500 text-xs">
+                    <span className="text-[var(--negative)] text-xs">
                       {row.error || "—"}
                     </span>
                   )}

src/components/import/ImportReportPanel.tsx

@@ -30,19 +30,19 @@ export default function ImportReportPanel({
       icon: CheckCircle,
       label: t("import.report.imported"),
       value: report.importedCount,
-      color: "text-emerald-500",
+      color: "text-[var(--positive)]",
     },
     {
       icon: AlertTriangle,
       label: t("import.report.skippedDuplicates"),
       value: report.skippedDuplicates,
-      color: "text-amber-500",
+      color: "text-[var(--accent)]",
     },
     {
       icon: XCircle,
       label: t("import.report.errors"),
       value: report.errorCount,
-      color: "text-red-500",
+      color: "text-[var(--negative)]",
     },
     {
       icon: Tag,
@@ -85,7 +85,7 @@ export default function ImportReportPanel({
       {/* Errors list */}
       {report.errors.length > 0 && (
         <div>
-          <h3 className="text-sm font-semibold mb-2 text-red-500">
+          <h3 className="text-sm font-semibold mb-2 text-[var(--negative)]">
             {t("import.report.errorDetails")}
           </h3>
           <div className="max-h-48 overflow-y-auto rounded-xl border border-[var(--border)]">
@@ -104,7 +104,7 @@ export default function ImportReportPanel({
                 {report.errors.map((err, i) => (
                   <tr key={i}>
                     <td className="px-3 py-2">{err.rowIndex + 1}</td>
-                    <td className="px-3 py-2 text-red-500">{err.message}</td>
+                    <td className="px-3 py-2 text-[var(--negative)]">{err.message}</td>
                   </tr>
                 ))}
               </tbody>

src/pages/ImportPage.tsx

@@ -35,9 +35,9 @@ export default function ImportPage() {
 
       {/* Error banner */}
       {state.error && (
-        <div className="mb-4 p-3 rounded-xl bg-red-50 dark:bg-red-950/20 border border-red-200 dark:border-red-800 flex items-center gap-2">
-          <AlertCircle size={16} className="text-red-500 shrink-0" />
-          <p className="text-sm text-red-700 dark:text-red-300">
+        <div className="mb-4 p-3 rounded-xl bg-[var(--card)] border-2 border-[var(--negative)] flex items-center gap-2">
+          <AlertCircle size={16} className="text-[var(--negative)] shrink-0" />
+          <p className="text-sm text-[var(--foreground)]">
             {state.error}
           </p>
         </div>

src/services/importedFileService.ts

@@ -32,6 +32,19 @@ export async function createImportedFile(file: {
   notes?: string;
 }): Promise<number> {
   const db = await getDb();
+  // Check if file already exists (e.g. from a previous failed import)
+  const existing = await db.select<ImportedFile[]>(
+    "SELECT id FROM imported_files WHERE source_id = $1 AND file_hash = $2",
+    [file.source_id, file.file_hash]
+  );
+  if (existing.length > 0) {
+    await db.execute(
+      `UPDATE imported_files SET filename = $1, row_count = $2, status = $3, notes = $4, import_date = CURRENT_TIMESTAMP WHERE id = $5`,
+      [file.filename, file.row_count, file.status, file.notes || null, existing[0].id]
+    );
+    return existing[0].id;
+  }
+
   const result = await db.execute(
     `INSERT INTO imported_files (source_id, filename, file_hash, row_count, status, notes)
      VALUES ($1, $2, $3, $4, $5, $6)`,