feat: redesign bottom navigation with day-picker styling

- Add a compact sky-blue rounded navigation group based on the day picker geometry.
- Use coral for the selected destination and the separate global add button.
- Add a functional global Add Class action that works from every tab.
- Cover the global navigation action with Playwright.

components/global-add-class.tsx

@@ -0,0 +1,35 @@
+import { createContext, useContext, useMemo, useState, type ReactNode } from 'react';
+
+import { AddClassModal } from '@/components/add-class-modal';
+import { dateKey } from '@/lib/date';
+
+type GlobalAddClassValue = {
+  openAddClass: () => void;
+  revision: number;
+};
+
+const GlobalAddClassContext = createContext<GlobalAddClassValue | null>(null);
+
+export function GlobalAddClassProvider({ children }: { children: ReactNode }) {
+  const [visible, setVisible] = useState(false);
+  const [revision, setRevision] = useState(0);
+  const value = useMemo(() => ({ openAddClass: () => setVisible(true), revision }), [revision]);
+
+  return (
+    <GlobalAddClassContext.Provider value={value}>
+      {children}
+      <AddClassModal
+        visible={visible}
+        date={dateKey(new Date())}
+        onClose={() => setVisible(false)}
+        onAdded={() => setRevision((current) => current + 1)}
+      />
+    </GlobalAddClassContext.Provider>
+  );
+}
+
+export function useGlobalAddClass() {
+  const value = useContext(GlobalAddClassContext);
+  if (!value) throw new Error('useGlobalAddClass must be used within GlobalAddClassProvider');
+  return value;
+}

components/ui/bottom-tab-bar.tsx

@@ -2,7 +2,8 @@ import { Ionicons } from '@expo/vector-icons';
 import type { BottomTabBarProps } from '@react-navigation/bottom-tabs';
 import * as Haptics from 'expo-haptics';
 import { Platform, Pressable, StyleSheet, View } from 'react-native';
-import { AppText } from './app-text';
+
+import { useGlobalAddClass } from '@/components/global-add-class';
 import { colors, radius, shadow, size, spacing } from './tokens';
 
 const tabConfig = {
@@ -12,45 +13,123 @@ const tabConfig = {
   settings: { label: 'Settings', icon: 'settings-outline', activeIcon: 'settings' },
 } as const;
 
-/** Floating, label-forward dock that keeps the active destination prominent without covering the page in a solid bar. */
-export function BottomTabBar({ state, descriptors, navigation, insets }: BottomTabBarProps) {
-  return <View pointerEvents="box-none" style={[styles.floatingArea, { paddingBottom: Math.max(insets.bottom, spacing[4]) }]}>
-    <View style={styles.bar}>
-      {state.routes.map((route, index) => {
-        const focused = state.index === index;
-        const config = tabConfig[route.name as keyof typeof tabConfig];
-        if (!config) return null;
-        const options = descriptors[route.key].options;
-        const label = options.tabBarLabel === undefined || typeof options.tabBarLabel === 'string' ? options.tabBarLabel ?? config.label : config.label;
-        const onPress = () => {
-          const event = navigation.emit({ type: 'tabPress', target: route.key, canPreventDefault: true });
-          if (!focused && !event.defaultPrevented) {
-            if (Platform.OS !== 'web') void Haptics.selectionAsync();
-            navigation.navigate(route.name);
-          }
-        };
-        const onLongPress = () => navigation.emit({ type: 'tabLongPress', target: route.key });
-        return <Pressable
-          key={route.key}
-          accessibilityRole="button"
-          accessibilityLabel={typeof label === 'string' ? label : config.label}
-          accessibilityState={{ selected: focused }}
-          onPress={onPress}
-          onLongPress={onLongPress}
-          style={({ pressed }) => [styles.tab, focused && styles.tabActive, pressed && styles.pressed]}>
-          <Ionicons name={focused ? config.activeIcon : config.icon} size={focused ? 19 : 20} color={focused ? colors.neutral.surface : colors.neutral.textSecondary} />
-          <AppText variant="caption" color={focused ? colors.neutral.surface : colors.neutral.textSecondary} numberOfLines={1} style={styles.label}>{label}</AppText>
-        </Pressable>;
-      })}
+/** Compact floating navigation group paired with a persistent global add action. */
+export function BottomTabBar({ state, navigation, insets }: BottomTabBarProps) {
+  const { openAddClass } = useGlobalAddClass();
+  const feedback = () => {
+    if (Platform.OS !== 'web') void Haptics.selectionAsync();
+  };
+
+  const addClass = () => {
+    feedback();
+    navigation.navigate('index');
+    // Defer until the Today scene is active so the modal is not dismissed by the tab transition.
+    setTimeout(openAddClass, 0);
+  };
+
+  return (
+    <View pointerEvents="box-none" style={[styles.floatingArea, { paddingBottom: Math.max(insets.bottom, spacing[4]) }]}>
+      <View style={styles.navigationGroup}>
+        {state.routes.map((route, index) => {
+          const focused = state.index === index;
+          const config = tabConfig[route.name as keyof typeof tabConfig];
+          if (!config) return null;
+
+          const onPress = () => {
+            const event = navigation.emit({ type: 'tabPress', target: route.key, canPreventDefault: true });
+            if (!focused && !event.defaultPrevented) {
+              feedback();
+              navigation.navigate(route.name);
+            }
+          };
+
+          const onLongPress = () => navigation.emit({ type: 'tabLongPress', target: route.key });
+
+          return (
+            <Pressable
+              key={route.key}
+              accessibilityRole="button"
+              accessibilityLabel={config.label}
+              accessibilityState={{ selected: focused }}
+              onPress={onPress}
+              onLongPress={onLongPress}
+              style={({ pressed }) => [styles.tab, focused && styles.tabActive, pressed && styles.pressed]}>
+              <Ionicons
+                name={focused ? config.activeIcon : config.icon}
+                size={21}
+                color={focused ? colors.brand.ink : colors.neutral.textSecondary}
+              />
+            </Pressable>
+          );
+        })}
+      </View>
+
+      <Pressable
+        accessibilityRole="button"
+        accessibilityLabel="Add a class"
+        onPress={addClass}
+        style={({ pressed }) => [styles.addButton, pressed && styles.addPressed]}>
+        <Ionicons name="add" size={26} color={colors.brand.ink} />
+      </Pressable>
     </View>
-  </View>;
+  );
 }
 
 const styles = StyleSheet.create({
-  floatingArea: { position: 'absolute', left: 0, right: 0, bottom: 0, paddingHorizontal: spacing[4], paddingTop: spacing[3], backgroundColor: 'transparent' },
-  bar: { minHeight: size.touchTargetMin + spacing[3], flexDirection: 'row', alignItems: 'center', gap: 2, padding: spacing[2], borderRadius: radius.sheet, borderCurve: 'continuous', borderWidth: 1, borderColor: colors.neutral.border, backgroundColor: colors.neutral.surface, ...shadow.floating },
-  tab: { minHeight: size.touchTargetMin, flex: 1, flexDirection: 'column', alignItems: 'center', justifyContent: 'center', gap: 2, borderRadius: radius.pill, borderCurve: 'continuous', paddingHorizontal: spacing[1] },
-  tabActive: { flexDirection: 'row', flexGrow: 1.15, gap: spacing[1] + 2, backgroundColor: colors.brand.cobalt, paddingHorizontal: spacing[3] },
-  label: { textAlign: 'center', flexShrink: 0 },
-  pressed: { opacity: 0.76 },
+  floatingArea: {
+    position: 'absolute',
+    left: 0,
+    right: 0,
+    bottom: 0,
+    flexDirection: 'row',
+    alignItems: 'center',
+    gap: spacing[3],
+    paddingHorizontal: spacing[5],
+    paddingTop: spacing[3],
+    backgroundColor: 'transparent',
+  },
+  navigationGroup: {
+    flex: 1,
+    minHeight: 58,
+    flexDirection: 'row',
+    alignItems: 'center',
+    gap: spacing[1],
+    padding: spacing[2],
+    borderRadius: radius.feature,
+    borderCurve: 'continuous',
+    borderWidth: 1,
+    borderColor: '#DCEEF8',
+    backgroundColor: colors.brand.skySoft,
+    ...shadow.floating,
+  },
+  tab: {
+    minWidth: size.touchTargetMin,
+    minHeight: size.touchTargetMin,
+    flex: 1,
+    alignItems: 'center',
+    justifyContent: 'center',
+    borderRadius: radius.control,
+    borderCurve: 'continuous',
+  },
+  tabActive: {
+    backgroundColor: colors.brand.coral,
+  },
+  addButton: {
+    width: 58,
+    height: 58,
+    alignItems: 'center',
+    justifyContent: 'center',
+    borderRadius: radius.feature,
+    borderCurve: 'continuous',
+    backgroundColor: colors.brand.coral,
+    ...shadow.floating,
+  },
+  pressed: {
+    opacity: 0.76,
+    transform: [{ scale: 0.97 }],
+  },
+  addPressed: {
+    backgroundColor: colors.brand.coralSoft,
+    transform: [{ scale: 0.96 }],
+  },
 });