diff --git a/frontend/src/app/layout.tsx b/frontend/src/app/layout.tsx
index 759598f..5211967 100644
--- a/frontend/src/app/layout.tsx
+++ b/frontend/src/app/layout.tsx
@@ -66,7 +66,9 @@ export default async function RootLayout({ children }: { children: ReactNode })
         <AxeAccessibility />
         <OfflineBanner />
         <ErrorBoundary section="main">
-          <WalletProvider>{children}</WalletProvider>
+          <WalletProvider>
+            <AppShell>{children}</AppShell>
+          </WalletProvider>
         </ErrorBoundary>
       </body>
     </html>
diff --git a/frontend/src/components/AppShell.tsx b/frontend/src/components/AppShell.tsx
new file mode 100644
index 0000000..2b79e58
--- /dev/null
+++ b/frontend/src/components/AppShell.tsx
@@ -0,0 +1,136 @@
+'use client';
+
+/**
+ * AppShell — primary app-wide navigation (#1314).
+ *
+ * The landing page (`/`) already owns its own full marketing header/nav/
+ * footer (components/LandingPage.tsx — separate anchor-link nav for
+ * #features/#how-it-works/#about/#contact), so AppShell skips rendering
+ * on `/` to avoid a duplicate header there. Everywhere else (Markets,
+ * Statistics, Create Market, account, tx, and — conditionally, once an
+ * admin session exists — Admin) gets a persistent header with primary
+ * navigation and a minimal footer, matching the sub-nav pattern already
+ * established by app/admin/layout.tsx for its own section.
+ */
+
+import React, { useEffect, useState } from 'react';
+import Link from 'next/link';
+import { usePathname } from 'next/navigation';
+
+const NAV_ITEMS = [
+  { href: '/markets', label: 'Markets' },
+  { href: '/statistics', label: 'Statistics' },
+  { href: '/markets/create', label: 'Create Market' },
+];
+
+export function AppShell({ children }: { children: React.ReactNode }) {
+  const pathname = usePathname();
+  const [hasAdminSession, setHasAdminSession] = useState(false);
+
+  useEffect(() => {
+    setHasAdminSession(Boolean(sessionStorage.getItem('predictiq-admin-key')));
+  }, [pathname]);
+
+  const isLandingPage = pathname === '/';
+  const isAdminSection = pathname?.startsWith('/admin');
+
+  if (isLandingPage || isAdminSection) {
+    return <>{children}</>;
+  }
+
+  const navItems = hasAdminSession
+    ? [...NAV_ITEMS, { href: '/admin/content', label: 'Admin' }]
+    : NAV_ITEMS;
+
+  return (
+    <div style={{ display: 'flex', flexDirection: 'column', minHeight: '100vh' }}>
+      <a href="#app-main-content" className="skip-link">
+        Skip to main content
+      </a>
+
+      <header
+        role="banner"
+        style={{
+          borderBottom: '1px solid var(--border)',
+          backgroundColor: 'var(--surface)',
+          position: 'sticky',
+          top: 0,
+          zIndex: 100,
+        }}
+      >
+        <div
+          style={{
+            maxWidth: 'var(--container)',
+            margin: '0 auto',
+            padding: '1rem 1.5rem',
+            display: 'flex',
+            alignItems: 'center',
+            justifyContent: 'space-between',
+            gap: '1.5rem',
+          }}
+        >
+          <Link
+            href="/"
+            aria-label="PredictIQ Home"
+            style={{ textDecoration: 'none', fontFamily: 'var(--font-display)', fontWeight: 700, fontSize: '1.2rem' }}
+          >
+            <span style={{ color: 'var(--fg)' }}>Predict</span>
+            <span style={{ color: 'var(--gold)' }}>IQ</span>
+          </Link>
+
+          <nav aria-label="Primary navigation">
+            <ul
+              style={{
+                display: 'flex',
+                gap: '1.5rem',
+                listStyle: 'none',
+                margin: 0,
+                padding: 0,
+              }}
+            >
+              {navItems.map((item) => {
+                const isActive = pathname === item.href || pathname?.startsWith(`${item.href}/`);
+                return (
+                  <li key={item.href}>
+                    <Link
+                      href={item.href}
+                      aria-current={isActive ? 'page' : undefined}
+                      style={{
+                        textDecoration: 'none',
+                        fontSize: 'var(--text-sm)',
+                        fontWeight: 500,
+                        color: isActive ? 'var(--gold)' : 'var(--fg-muted)',
+                      }}
+                    >
+                      {item.label}
+                    </Link>
+                  </li>
+                );
+              })}
+            </ul>
+          </nav>
+        </div>
+      </header>
+
+      <main id="app-main-content" role="main" style={{ flex: 1 }}>
+        {children}
+      </main>
+
+      <footer
+        role="contentinfo"
+        style={{
+          borderTop: '1px solid var(--border)',
+          backgroundColor: 'var(--surface)',
+          padding: '1.5rem',
+          textAlign: 'center',
+          fontSize: 'var(--text-xs)',
+          color: 'var(--fg-muted)',
+        }}
+      >
+        © {new Date().getFullYear()} PredictIQ. Built on Stellar.
+      </footer>
+    </div>
+  );
+}
+
+export default AppShell;
diff --git a/frontend/src/components/ui/Button.tsx b/frontend/src/components/ui/Button.tsx
new file mode 100644
index 0000000..529191f
--- /dev/null
+++ b/frontend/src/components/ui/Button.tsx
@@ -0,0 +1,99 @@
+'use client';
+
+/**
+ * Button — shared design-system primitive (#1315).
+ *
+ * Every write action in this backlog (bet placement, market creation,
+ * resolution, admin actions) should funnel through this so loading/
+ * disabled states are handled consistently instead of ad hoc per form.
+ * Styling follows the existing Button in components/admin/Form.tsx (the
+ * closest prior art), generalized here to be usable outside the admin
+ * section too.
+ */
+
+import React from 'react';
+
+export type ButtonVariant = 'primary' | 'secondary' | 'danger' | 'ghost';
+
+export interface ButtonProps extends React.ButtonHTMLAttributes<HTMLButtonElement> {
+  variant?: ButtonVariant;
+  isLoading?: boolean;
+  leftIcon?: React.ReactNode;
+  rightIcon?: React.ReactNode;
+}
+
+function variantStyles(variant: ButtonVariant): React.CSSProperties {
+  switch (variant) {
+    case 'primary':
+      return { backgroundColor: 'var(--gold)', color: 'var(--on-primary)', border: 'none', fontWeight: 600 };
+    case 'danger':
+      return { backgroundColor: 'var(--destructive)', color: '#ffffff', border: 'none', fontWeight: 600 };
+    case 'secondary':
+      return {
+        backgroundColor: 'var(--surface-2)',
+        color: 'var(--fg)',
+        border: '1px solid var(--border-strong)',
+        fontWeight: 500,
+      };
+    case 'ghost':
+      return { backgroundColor: 'transparent', color: 'var(--fg-muted)', border: 'none', fontWeight: 500 };
+  }
+}
+
+export const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
+  (
+    { variant = 'primary', isLoading = false, leftIcon, rightIcon, children, disabled, className = '', style, ...props },
+    ref
+  ) => {
+    const isDisabled = disabled || isLoading;
+
+    return (
+      <button
+        ref={ref}
+        type={props.type ?? 'button'}
+        disabled={isDisabled}
+        aria-disabled={isDisabled}
+        aria-busy={isLoading || undefined}
+        className={`ui-btn ui-btn--${variant} ${className}`}
+        style={{
+          display: 'inline-flex',
+          alignItems: 'center',
+          justifyContent: 'center',
+          gap: '0.5rem',
+          padding: '0.65rem 1.25rem',
+          fontSize: 'var(--text-sm)',
+          fontFamily: 'inherit',
+          borderRadius: 'var(--radius-sm)',
+          cursor: isDisabled ? 'not-allowed' : 'pointer',
+          opacity: isDisabled ? 0.6 : 1,
+          transition: 'all var(--dur-fast)',
+          textDecoration: 'none',
+          ...variantStyles(variant),
+          ...style,
+        }}
+        {...props}
+      >
+        {isLoading && (
+          <span
+            aria-hidden="true"
+            style={{
+              display: 'inline-block',
+              width: '14px',
+              height: '14px',
+              border: '2px solid currentColor',
+              borderTopColor: 'transparent',
+              borderRadius: '50%',
+              animation: 'spin 0.8s linear infinite',
+            }}
+          />
+        )}
+        {!isLoading && leftIcon}
+        <span>{children}</span>
+        {!isLoading && rightIcon}
+      </button>
+    );
+  }
+);
+Button.displayName = 'Button';
+
+export default Button;
diff --git a/frontend/src/components/ui/Card.tsx b/frontend/src/components/ui/Card.tsx
new file mode 100644
index 0000000..3b1ab8e
--- /dev/null
+++ b/frontend/src/components/ui/Card.tsx
@@ -0,0 +1,124 @@
+/**
+ * Card — shared design-system container primitive (#1316).
+ *
+ * Market list items (#57), statistics tiles (#49), and admin panels
+ * (#89-97) each currently reinvent their own padding/border/shadow rules;
+ * this is the one shared container to converge on instead.
+ */
+
+import React from 'react';
+
+export interface CardProps extends React.HTMLAttributes<HTMLDivElement> {
+  /** Renders with a hover elevation/border-highlight, for clickable cards. */
+  interactive?: boolean;
+  /** Removes the default padding, for cards that manage their own inner layout. */
+  noPadding?: boolean;
+}
+
+export const Card = React.forwardRef<HTMLDivElement, CardProps>(
+  ({ interactive = false, noPadding = false, className = '', style, children, ...props }, ref) => {
+    return (
+      <div
+        ref={ref}
+        className={`ui-card ${interactive ? 'ui-card--interactive' : ''} ${className}`}
+        style={{
+          backgroundColor: 'var(--surface)',
+          border: '1px solid var(--border)',
+          borderRadius: 'var(--radius)',
+          boxShadow: 'var(--shadow-sm)',
+          padding: noPadding ? 0 : '1.25rem',
+          transition: interactive ? 'border-color var(--dur-fast), box-shadow var(--dur-fast)' : undefined,
+          cursor: interactive ? 'pointer' : undefined,
+          ...style,
+        }}
+        {...props}
+      >
+        {children}
+      </div>
+    );
+  }
+);
+Card.displayName = 'Card';
+
+export interface CardHeaderProps extends React.HTMLAttributes<HTMLDivElement> {}
+
+export function CardHeader({ className = '', style, children, ...props }: CardHeaderProps) {
+  return (
+    <div
+      className={`ui-card__header ${className}`}
+      style={{
+        display: 'flex',
+        alignItems: 'flex-start',
+        justifyContent: 'space-between',
+        gap: '1rem',
+        marginBottom: '0.85rem',
+        ...style,
+      }}
+      {...props}
+    >
+      {children}
+    </div>
+  );
+}
+
+export interface CardTitleProps extends React.HTMLAttributes<HTMLHeadingElement> {
+  as?: 'h2' | 'h3' | 'h4';
+}
+
+export function CardTitle({ as = 'h3', className = '', style, children, ...props }: CardTitleProps) {
+  const Heading = as;
+  return (
+    <Heading
+      className={`ui-card__title ${className}`}
+      style={{
+        margin: 0,
+        fontSize: 'var(--text-lg)',
+        fontFamily: 'var(--font-display)',
+        fontWeight: 600,
+        color: 'var(--fg)',
+        ...style,
+      }}
+      {...props}
+    >
+      {children}
+    </Heading>
+  );
+}
+
+export interface CardBodyProps extends React.HTMLAttributes<HTMLDivElement> {}
+
+export function CardBody({ className = '', style, children, ...props }: CardBodyProps) {
+  return (
+    <div
+      className={`ui-card__body ${className}`}
+      style={{ fontSize: 'var(--text-sm)', color: 'var(--fg-muted)', lineHeight: 1.5, ...style }}
+      {...props}
+    >
+      {children}
+    </div>
+  );
+}
+
+export interface CardFooterProps extends React.HTMLAttributes<HTMLDivElement> {}
+
+export function CardFooter({ className = '', style, children, ...props }: CardFooterProps) {
+  return (
+    <div
+      className={`ui-card__footer ${className}`}
+      style={{
+        marginTop: '1rem',
+        paddingTop: '0.85rem',
+        borderTop: '1px solid var(--border)',
+        display: 'flex',
+        alignItems: 'center',
+        gap: '0.75rem',
+        ...style,
+      }}
+      {...props}
+    >
+      {children}
+    </div>
+  );
+}
+
+export default Card;
diff --git a/frontend/src/styles/tokens.css b/frontend/src/styles/tokens.css
index 59ae3e9..673fafe 100644
--- a/frontend/src/styles/tokens.css
+++ b/frontend/src/styles/tokens.css
@@ -61,9 +61,18 @@
 
   --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
   --shadow: 0 18px 40px -18px rgba(0, 0, 0, 0.7);
+  --shadow-lg: 0 30px 60px -20px rgba(0, 0, 0, 0.8);
   --shadow-glow-gold: 0 0 0 1px rgba(245, 158, 11, 0.15), 0 20px 60px -20px rgba(245, 158, 11, 0.35);
   --shadow-glow-purple: 0 24px 70px -24px rgba(139, 92, 246, 0.45);
 
+  /* Issue #1313: these were referenced elsewhere in the app only via
+     `var(--x, <hardcoded fallback>)`, bypassing the centralized token
+     system entirely (so dark-mode/#22-23 and contrast-check/#21 tooling
+     had nothing to hook into for them). Aliased to their equivalent
+     existing tokens rather than introducing new independent colors. */
+  --danger: var(--destructive);
+  --border-color: var(--border);
+
   color-scheme: dark;
 }