chore: add frontend/src/components/layout/BottomTab.tsx

frontend/src/components/layout/BottomTab.tsx

@@ -0,0 +1,119 @@
+import React from 'react';
+import { NavLink, useLocation } from 'react-router-dom';
+
+const BottomTab: React.FC = () => {
+  const location = useLocation();
+
+  const navItems = [
+    { path: '/', label: '首页', icon: HomeIcon },
+    { path: '/record', label: '记账', icon: RecordIcon },
+    { path: '/budget', label: '预算', icon: BudgetIcon },
+    { path: '/statistics', label: '统计', icon: StatisticsIcon },
+  ];
+
+  return (
+    <nav className="bottom-tab-bar" role="navigation" aria-label="底部导航">
+      {navItems.map((item) => (
+        <NavLink
+          key={item.path}
+          to={item.path}
+          className={({ isActive }) =>
+            `tab-item ${isActive ? 'active' : ''}`
+          }
+          aria-current={location.pathname === item.path ? 'page' : undefined}
+        >
+          <item.icon />
+          <span>{item.label}</span>
+        </NavLink>
+      ))}
+      
+      <style>{`
+        :root {
+          --primary: #0052ff;
+          --surface: #ffffff;
+          --border: #e5e5e5;
+          --text-secondary: #737373;
+        }
+
+        .bottom-tab-bar {
+          position: fixed;
+          bottom: 0;
+          left: 0;
+          right: 0;
+          height: 64px;
+          background: var(--surface);
+          border-top: 1px solid var(--border);
+          display: flex;
+          justify-content: space-around;
+          align-items: center;
+          padding: 0;
+          z-index: 100;
+        }
+
+        .tab-item {
+          display: flex;
+          flex-direction: column;
+          align-items: center;
+          justify-content: center;
+          gap: 2px;
+          flex: 1;
+          height: 100%;
+          color: var(--text-secondary);
+          text-decoration: none;
+          font-size: 11px;
+          font-weight: 500;
+          transition: color 0.15s ease;
+        }
+
+        .tab-item.active {
+          color: var(--primary);
+        }
+
+        @media (min-width: 768px) {
+          .bottom-tab-bar {
+            display: none;
+          }
+        }
+      `}</style>
+    </nav>
+  );
+};
+
+function HomeIcon() {
+  return (
+    <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" width="24" height="24">
+      <path d="M3 9l9-7 9 7v11a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2z"/>
+      <polyline points="9 22 9 12 15 12 15 22"/>
+    </svg>
+  );
+}
+
+function RecordIcon() {
+  return (
+    <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" width="24" height="24">
+      <path d="M12 2v20M17 5H9.5a3.5 3.5 0 0 0 0 7h5a3.5 3.5 0 0 1 0 7H6"/>
+    </svg>
+  );
+}
+
+function BudgetIcon() {
+  return (
+    <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" width="24" height="24">
+      <rect x="2" y="3" width="20" height="14" rx="2" ry="2"/>
+      <line x1="8" y1="21" x2="16" y2="21"/>
+      <line x1="12" y1="17" x2="12" y2="21"/>
+    </svg>
+  );
+}
+
+function StatisticsIcon() {
+  return (
+    <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" width="24" height="24">
+      <line x1="18" y1="20" x2="18" y2="10"/>
+      <line x1="12" y1="20" x2="12" y2="4"/>
+      <line x1="6" y1="20" x2="6" y2="14"/>
+    </svg>
+  );
+}
+
+export default BottomTab;