diff --git a/backend/.env.example b/backend/.env.example
index a6563d32..e19613cd 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -73,6 +73,7 @@ ADMIN_AUDIT_LOG_STORAGE=hybrid
 WEBHOOK_VERIFICATION_TIMEOUT_MS=5000
 WEBHOOK_CHALLENGE_TTL_SECONDS=900
 WEBHOOK_ALLOW_UNVERIFIED=false
+WEBHOOK_SIGNATURE_MAX_SKEW_MS=300000
 
 # Prisma runtime connection settings
 PRISMA_POOL_SIZE=10
diff --git a/backend/README.md b/backend/README.md
index 0a055356..e44ee0b1 100644
--- a/backend/README.md
+++ b/backend/README.md
@@ -290,6 +290,28 @@ export or re-register the live mappings before deploying/restarting; otherwise
 the persistent tables will start empty and only new registrations will be
 preserved.
 
+## Webhook Failure Behavior
+
+Incoming webhook deliveries must identify a configured endpoint and contain a
+valid schema version, event type, delivery ID, and ISO-8601 `sentAt` timestamp.
+The HMAC-SHA256 signature is checked before replay state is recorded. Invalid
+signatures, malformed envelopes, unknown endpoints, missing secrets, stale
+timestamps, and repeated delivery IDs are rejected without application
+processing.
+
+Outbound delivery attempts use exponential backoff with jitter. After
+`WEBHOOK_MAX_ATTEMPTS` failures, the delivery is marked failed and copied to
+the webhook dead-letter queue. Operators can inspect it through
+`GET /admin/webhooks/dead-letter` and explicitly retry it with
+`POST /admin/webhooks/dead-letter/:id/retry`. A retry creates a new delivery
+attempt while retaining the original failure record for auditability.
+
+The replay timestamp window is controlled by
+`WEBHOOK_SIGNATURE_MAX_SKEW_MS` (default: 300000 ms). Consumers should return
+a non-2xx response for invalid webhook requests; the sender treats non-2xx and
+network/time-out failures as retryable until the dead-letter threshold is
+reached.
+
 ## Issues Addressed
 
 ### Issue #145: Rate Limiting
diff --git a/backend/src/auditLog.ts b/backend/src/auditLog.ts
index 837f63b5..42d462b7 100644
--- a/backend/src/auditLog.ts
+++ b/backend/src/auditLog.ts
@@ -31,7 +31,10 @@ interface AuditLogFilters {
   action?: string;
   path?: string;
   statusCode?: number;
+  from?: string;
+  to?: string;
   limit?: number;
+  offset?: number;
 }
 
 const entries: AuditLogEntry[] = [];
@@ -71,6 +74,23 @@ export function createAdminAuditMiddleware() {
 }
 
 export function getAuditLogs(filters: AuditLogFilters = {}): AuditLogEntry[] {
+  const normalizedLimit = Math.max(1, Math.min(filters.limit ?? 100, 500));
+  const normalizedOffset = Math.max(0, filters.offset ?? 0);
+  return filterAuditLogs(filters)
+    .sort((left, right) => {
+      const timestampOrder = right.timestamp.localeCompare(left.timestamp);
+      return timestampOrder !== 0
+        ? timestampOrder
+        : right.id.localeCompare(left.id);
+    })
+    .slice(normalizedOffset, normalizedOffset + normalizedLimit);
+}
+
+export function countAuditLogs(filters: AuditLogFilters = {}): number {
+  return filterAuditLogs(filters).length;
+}
+
+function filterAuditLogs(filters: AuditLogFilters): AuditLogEntry[] {
   const statusFilter =
     typeof filters.statusCode === 'number' && Number.isFinite(filters.statusCode)
       ? filters.statusCode
@@ -93,11 +113,27 @@ export function getAuditLogs(filters: AuditLogFilters = {}): AuditLogEntry[] {
       return false;
     }
 
+    if (filters.from && entry.timestamp < normalizeAuditDate(filters.from, false)) {
+      return false;
+    }
+
+    if (filters.to && entry.timestamp > normalizeAuditDate(filters.to, true)) {
+      return false;
+    }
+
     return true;
   });
 
-  const normalizedLimit = Math.max(1, Math.min(filters.limit ?? 100, 500));
-  return filtered.slice(0, normalizedLimit);
+  return filtered;
+}
+
+function normalizeAuditDate(value: string, endOfDay: boolean): string {
+  if (/^\d{4}-\d{2}-\d{2}$/.test(value)) {
+    return `${value}T${endOfDay ? '23:59:59.999' : '00:00:00.000'}Z`;
+  }
+
+  const timestamp = Date.parse(value);
+  return Number.isNaN(timestamp) ? value : new Date(timestamp).toISOString();
 }
 
 export function getAuditLogMetrics() {
diff --git a/backend/src/index.ts b/backend/src/index.ts
index 27da7a57..d51720ac 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -23,7 +23,8 @@ import {
   loadConfig as loadRateLimiterConfig,
 } from './rateLimiter';
 import { idempotencyStore } from './idempotency';
-import { createAdminAuditMiddleware, getAuditLogs, getAuditLogMetrics } from './auditLog';
+import { createAdminAuditMiddleware, getAuditLogs, countAuditLogs, getAuditLogMetrics } from './auditLog';
+import { AuditLogQuerySchema } from './middleware/validate';
 import { recordAdminAuditLog } from './adminAudit';
 import {
   recordAdminConfigChange, listAdminConfigChanges, getActorFromRequest
@@ -3101,17 +3102,21 @@ app.post('/api/v1/webhooks/verify', validate({ body: WebhookVerifyBodySchema }),
 /**
  * GET /admin/audit/logs - list admin activity logs
  */
-app.get('/admin/audit/logs', validateApiKey, (req: Request, res: Response) => {
+app.get('/admin/audit/logs', validateApiKey, validate({ query: AuditLogQuerySchema }), (req: Request, res: Response) => {
   const statusCode = req.query.statusCode ? parseInt(String(req.query.statusCode), 10) : undefined;
   const limit = parseLimited(req.query.limit, 100, 1, 500);
-
-  const logs = getAuditLogs({
+  const page = parseLimited(req.query.page, 1, 1, 1000000);
+  const offset = (page - 1) * limit;
+  const filters = {
     actor: req.query.actor ? String(req.query.actor) : undefined,
     action: req.query.action ? String(req.query.action) : undefined,
     path: req.query.path ? String(req.query.path) : undefined,
     statusCode,
-    limit: limit + 1,
-  });
+    from: req.query.from ? String(req.query.from) : undefined,
+    to: req.query.to ? String(req.query.to) : undefined,
+  };
+
+  const logs = getAuditLogs({ ...filters, limit: limit + 1, offset });
   const { data, hasNextPage } = paginateByLimit(logs, limit);
 
   sendStandardListEnvelope(res, {
@@ -3120,6 +3125,8 @@ app.get('/admin/audit/logs', validateApiKey, (req: Request, res: Response) => {
     hasNextPage,
     extras: {
       logs: data,
+      page,
+      total: countAuditLogs(filters),
       metrics: getAuditLogMetrics(),
     },
   });
@@ -3128,18 +3135,26 @@ app.get('/admin/audit/logs', validateApiKey, (req: Request, res: Response) => {
 /**
  * GET /admin/audit-logs - list admin audit entries (Issue #253)
  */
-app.get('/admin/audit-logs', validateApiKey, async (req: Request, res: Response) => {
+app.get('/admin/audit-logs', validateApiKey, validate({ query: AuditLogQuerySchema }), async (req: Request, res: Response) => {
   const limit = parseLimited(req.query.limit, 50, 1, 200);
-  const statusCode = req.query.statusCode
-    ? parseLimited(req.query.statusCode, 0, 100, 599)
+  const page = parseLimited(req.query.page, 1, 1, 1000000);
+  const offset = (page - 1) * limit;
+  const statusValue = req.query.statusCode ?? req.query.status;
+  const statusCode = statusValue
+    ? parseLimited(statusValue, 0, 100, 599)
     : undefined;
-
-  const rows = getAuditLogs({
-    action: typeof req.query.action === 'string' ? req.query.action : undefined,
+  const filters = {
+    action: typeof req.query.action === 'string'
+      ? req.query.action
+      : typeof req.query.type === 'string' ? req.query.type : undefined,
     actor: typeof req.query.actor === 'string' ? req.query.actor : undefined,
+    path: typeof req.query.path === 'string' ? req.query.path : undefined,
     statusCode,
-    limit: limit + 1,
-  });
+    from: typeof req.query.from === 'string' ? req.query.from : undefined,
+    to: typeof req.query.to === 'string' ? req.query.to : undefined,
+  };
+
+  const rows = getAuditLogs({ ...filters, limit: limit + 1, offset });
   const { data, hasNextPage } = paginateByLimit(rows, limit);
 
   void recordAdminAuditLog(req, 'audit-logs.read', 200, {
@@ -3154,6 +3169,8 @@ app.get('/admin/audit-logs', validateApiKey, async (req: Request, res: Response)
     extras: {
       meta: {
         count: data.length,
+        total: countAuditLogs(filters),
+        page,
         limit,
         timestamp: new Date().toISOString(),
       },
diff --git a/backend/src/types/validation.ts b/backend/src/types/validation.ts
index a9c10678..20041be1 100644
--- a/backend/src/types/validation.ts
+++ b/backend/src/types/validation.ts
@@ -41,6 +41,17 @@ export const TransactionListQuerySchema = PaginationQuerySchema.extend({
   to: z.string().optional(),
 }).passthrough();
 
+export const AuditLogQuerySchema = PaginationQuerySchema.extend({
+  actor: z.string().optional(),
+  action: z.string().optional(),
+  type: z.string().optional(),
+  path: z.string().optional(),
+  status: z.string().regex(/^\d+$/, 'status must be an HTTP status code').optional(),
+  statusCode: z.string().regex(/^\d+$/, 'statusCode must be an HTTP status code').optional(),
+  from: z.string().min(1).optional(),
+  to: z.string().min(1).optional(),
+}).passthrough();
+
 export const WebhookListQuerySchema = PaginationQuerySchema.extend({
   includeDeleted: z.enum(['true', 'false']).optional(),
   endpointId: z.string().optional(),
diff --git a/backend/src/webhookDelivery.ts b/backend/src/webhookDelivery.ts
index 9704497b..a348389c 100644
--- a/backend/src/webhookDelivery.ts
+++ b/backend/src/webhookDelivery.ts
@@ -539,6 +539,19 @@ export interface WebhookSignedEnvelope {
   deliveryId: string;
 }
 
+export type IncomingWebhookVerificationResult =
+  | { verified: true; envelope: WebhookSignedEnvelope }
+  | {
+      verified: false;
+      reason:
+        | 'unknown-endpoint'
+        | 'missing-secret'
+        | 'invalid-envelope'
+        | 'invalid-signature'
+        | 'stale-event'
+        | 'replayed-event';
+    };
+
 function createReplayCacheKey(endpointId: string, deliveryId: string): string {
   return `${endpointId}:${deliveryId}`;
 }
@@ -601,6 +614,59 @@ export function verifyWebhookSignature(
   return crypto.timingSafeEqual(providedBuffer, expectedBuffer);
 }
 
+export function verifyIncomingWebhookPayload(
+  endpointId: string,
+  envelope: unknown,
+  signature: unknown,
+): IncomingWebhookVerificationResult {
+  const endpoint = endpoints.get(endpointId);
+  if (!endpoint || endpoint.deletedAt) {
+    return { verified: false, reason: 'unknown-endpoint' };
+  }
+  if (!endpoint.secret) {
+    return { verified: false, reason: 'missing-secret' };
+  }
+  if (!envelope || typeof envelope !== 'object' || Array.isArray(envelope)) {
+    return { verified: false, reason: 'invalid-envelope' };
+  }
+
+  const candidate = envelope as Partial<WebhookSignedEnvelope>;
+  if (
+    candidate.schemaVersion !== WEBHOOK_SCHEMA_VERSION ||
+    typeof candidate.eventType !== 'string' ||
+    !WEBHOOK_EVENT_TYPES.includes(candidate.eventType as WebhookEventType) ||
+    typeof candidate.sentAt !== 'string' ||
+    typeof candidate.deliveryId !== 'string' ||
+    candidate.deliveryId.length === 0 ||
+    !candidate.payload ||
+    typeof candidate.payload !== 'object' ||
+    Array.isArray(candidate.payload)
+  ) {
+    return { verified: false, reason: 'invalid-envelope' };
+  }
+
+  if (
+    typeof signature !== 'string' ||
+    !verifyWebhookSignature(endpoint.secret, envelope, signature)
+  ) {
+    return { verified: false, reason: 'invalid-signature' };
+  }
+
+  const sentAtMs = Date.parse(candidate.sentAt);
+  if (
+    Number.isNaN(sentAtMs) ||
+    Math.abs(Date.now() - sentAtMs) > webhookSignatureMaxSkewMs
+  ) {
+    return { verified: false, reason: 'stale-event' };
+  }
+
+  if (!markWebhookDeliverySeen(endpointId, candidate.deliveryId, candidate.sentAt)) {
+    return { verified: false, reason: 'replayed-event' };
+  }
+
+  return { verified: true, envelope: candidate as WebhookSignedEnvelope };
+}
+
 function encodeDeliveryCursor(delivery: WebhookDeliveryRecord): string {
   return Buffer.from(JSON.stringify({ createdAt: delivery.createdAt, id: delivery.id })).toString('base64url');
 }
diff --git a/frontend/src/components/Tabs.css b/frontend/src/components/Tabs.css
index 59336228..83c22ba7 100644
--- a/frontend/src/components/Tabs.css
+++ b/frontend/src/components/Tabs.css
@@ -36,7 +36,7 @@
 
 .tabs-trigger:hover {
   color: var(--text-primary);
-  background: rgba(255, 255, 255, 0.03);
+  background: var(--bg-surface-hover);
 }
 
 .tabs-trigger.active {
diff --git a/frontend/src/components/ui/Table.css b/frontend/src/components/ui/Table.css
index 167bb136..4452ccf9 100644
--- a/frontend/src/components/ui/Table.css
+++ b/frontend/src/components/ui/Table.css
@@ -3,7 +3,7 @@
   overflow-x: auto;
   border-radius: var(--radius-md);
   border: 1px solid var(--border-glass);
-  background: rgba(0, 0, 0, 0.1);
+  background: var(--bg-control);
 }
 
 .ui-table {
@@ -21,7 +21,7 @@
   letter-spacing: 0.05em;
   font-size: var(--text-xs);
   border-bottom: 1px solid var(--border-glass);
-  background: rgba(255, 255, 255, 0.02);
+  background: var(--bg-muted);
 }
 
 .ui-td {
@@ -36,7 +36,7 @@
 }
 
 .ui-tr:hover .ui-td {
-  background: rgba(255, 255, 255, 0.03);
+  background: var(--bg-surface-hover);
 }
 
 .ui-th.align-center, .ui-td.align-center { text-align: center; }
@@ -57,5 +57,5 @@
 }
 
 .table-container::-webkit-scrollbar-thumb:hover {
-  background: rgba(255, 255, 255, 0.15);
+  background: var(--border-subtle);
 }
diff --git a/frontend/src/lib/optimisticVaultCache.ts b/frontend/src/lib/optimisticVaultCache.ts
index b51402d6..9bc0b2bb 100644
--- a/frontend/src/lib/optimisticVaultCache.ts
+++ b/frontend/src/lib/optimisticVaultCache.ts
@@ -175,8 +175,10 @@ export function applyOptimisticVaultPatch(
   const walletDelta = action === "deposit" ? -amount : amount;
   const vaultDelta = action === "deposit" ? amount : -amount;
 
-  queryClient.setQueryData<number>(keys.balanceKey, (current = 0) =>
-    Math.max(current + walletDelta, 0),
+  queryClient.setQueryData<number | undefined>(keys.balanceKey, (current) =>
+    typeof current === "number"
+      ? Math.max(current + walletDelta, 0)
+      : current,
   );
   queryClient.setQueryData<PortfolioHolding[] | undefined>(
     keys.holdingsKey,
diff --git a/frontend/src/styles/theme.css b/frontend/src/styles/theme.css
index 49104696..8494fca5 100644
--- a/frontend/src/styles/theme.css
+++ b/frontend/src/styles/theme.css
@@ -14,12 +14,14 @@
   --bg-elevated: rgba(24, 26, 36, 0.92);
   --bg-overlay: rgba(10, 11, 16, 0.8);
   --bg-muted: rgba(0, 0, 0, 0.2);
+  --bg-control: rgba(0, 0, 0, 0.24);
   --bg-gradient-1: rgba(112, 0, 255, 0.08);
   --bg-gradient-2: rgba(0, 240, 255, 0.05);
 
   --border-glass: rgba(255, 255, 255, 0.08);
   --border-glass-glow: rgba(0, 240, 255, 0.3);
   --border-subtle: rgba(255, 255, 255, 0.12);
+  --border-control: rgba(255, 255, 255, 0.18);
 
   --accent-cyan: #00f0ff;
   --accent-cyan-dim: rgba(0, 240, 255, 0.2);
@@ -35,6 +37,7 @@
   --text-primary: #ffffff;
   --text-secondary: #a8b8cc;
   --text-tertiary: #8494a7;
+  --text-placeholder: #9aaabd;
   --text-inverse: #0f172a;
   --text-warning: #f59e0b;
   --text-success: #22c55e;
@@ -66,12 +69,14 @@
   --bg-elevated: #ffffff;
   --bg-overlay: rgba(255, 255, 255, 0.8);
   --bg-muted: rgba(15, 23, 42, 0.05);
+  --bg-control: rgba(255, 255, 255, 0.92);
   --bg-gradient-1: rgba(126, 34, 206, 0.04);
   --bg-gradient-2: rgba(2, 132, 199, 0.03);
 
   --border-glass: rgba(0, 0, 0, 0.08);
   --border-glass-glow: rgba(0, 136, 204, 0.2);
   --border-subtle: rgba(15, 23, 42, 0.12);
+  --border-control: rgba(15, 23, 42, 0.2);
 
   --accent-cyan: #0284c7;
   --accent-cyan-dim: rgba(2, 132, 199, 0.1);
@@ -87,6 +92,7 @@
   --text-primary: #0f172a;
   --text-secondary: #40505f;
   --text-tertiary: #5a6a7d;
+  --text-placeholder: #526273;
   --text-inverse: #ffffff;
   --text-warning: #b45309;
   --text-success: #15803d;
@@ -130,6 +136,26 @@ body {
   color: var(--text-primary);
 }
 
+button,
+input,
+select,
+textarea {
+  color: var(--text-primary);
+}
+
+input,
+select,
+textarea {
+  background-color: var(--bg-control);
+  border-color: var(--border-control);
+}
+
+input::placeholder,
+textarea::placeholder {
+  color: var(--text-placeholder);
+  opacity: 1;
+}
+
 [data-sonner-toaster] {
   font-family: var(--font-sans);
 }