feat: Add collapsible sections and mobile grid layout

- Convert Active Sessions and Trusted Devices to collapsible Accordion components
- Display count badge in collapsed state
- Show loading state in accordion header
- Implement 2-card grid layout on mobile (xs=6)
- Responsive card sizing and spacing
- Centered layout on mobile, horizontal on desktop
- Hide full birthdate on mobile, show age only

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

maternal-web/app/children/page.tsx

@@ -214,9 +214,9 @@ export default function ChildrenPage() {
               </Grid>
             </Grid>
           ) : (
-            <Grid container spacing={3}>
+            <Grid container spacing={{ xs: 2, sm: 3 }}>
               {children.map((child, index) => (
-                <Grid item xs={12} sm={6} key={child.id}>
+                <Grid item xs={6} sm={6} md={4} key={child.id}>
                   <motion.div
                     initial={{ opacity: 0, y: 20 }}
                     animate={{ opacity: 1, y: 0 }}
@@ -225,43 +225,43 @@ export default function ChildrenPage() {
                     <Paper
                       elevation={0}
                       sx={{
-                        p: 3,
+                        p: { xs: 2, sm: 3 },
                         borderRadius: 3,
                         bgcolor: 'background.paper',
                         border: 1,
                         borderColor: 'divider'
                       }}
                     >
-                      <Box sx={{ display: 'flex', alignItems: 'flex-start', gap: 2 }}>
+                      <Box sx={{ display: 'flex', flexDirection: { xs: 'column', sm: 'row' }, alignItems: { xs: 'center', sm: 'flex-start' }, gap: { xs: 1, sm: 2 } }}>
                         <Avatar
                           src={child.photoUrl}
                           sx={{
-                            width: 64,
-                            height: 64,
+                            width: { xs: 48, sm: 64 },
+                            height: { xs: 48, sm: 64 },
                             bgcolor: 'primary.light',
-                            fontSize: 24
+                            fontSize: { xs: 20, sm: 24 }
                           }}
                         >
                           {child.name[0]}
                         </Avatar>
-                        <Box sx={{ flexGrow: 1 }}>
-                          <Typography variant="h6" fontWeight="600">{child.name}</Typography>
-                          <Typography variant="body2" color="text.secondary">
+                        <Box sx={{ flexGrow: 1, textAlign: { xs: 'center', sm: 'left' }, width: '100%' }}>
+                          <Typography variant="h6" fontWeight="600" sx={{ fontSize: { xs: '1rem', sm: '1.25rem' } }}>{child.name}</Typography>
+                          <Typography variant="body2" color="text.secondary" sx={{ fontSize: { xs: '0.75rem', sm: '0.875rem' } }}>
                             {t(`gender.${child.gender}`)}
                           </Typography>
-                          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, mt: 1 }}>
+                          <Box sx={{ display: { xs: 'none', sm: 'flex' }, alignItems: 'center', gap: 1, mt: 1 }}>
                             <CalendarToday fontSize="small" color="action" />
                             <Typography variant="caption">
                               {formatDate(child.birthDate, 'PPP')}
                             </Typography>
                           </Box>
-                          <Typography variant="caption" color="primary.main">
+                          <Typography variant="caption" color="primary.main" sx={{ display: 'block', mt: 0.5 }}>
                             {t('age')}: {calculateAge(child.birthDate)}
                           </Typography>
                         </Box>
                       </Box>
 
-                      <Box sx={{ display: 'flex', gap: 1, mt: 2 }}>
+                      <Box sx={{ display: 'flex', gap: 1, mt: 2, justifyContent: { xs: 'center', sm: 'flex-start' } }}>
                         <IconButton size="small" color="primary" onClick={() => handleEditChild(child)}>
                           <Edit />
                         </IconButton>

maternal-web/app/settings/page.tsx

@@ -266,10 +266,9 @@ export default function SettingsPage() {
         initial={{ opacity: 0, y: 20 }}
         animate={{ opacity: 1, y: 0 }}
         transition={{ duration: 0.4, delay: 0.3 }}
+        style={{ marginBottom: '24px' }}
       >
-        <Box sx={{ mb: 3 }}>
         <SessionsManagement />
-        </Box>
       </motion.div>
 
       {/* Device Trust Management */}
@@ -277,10 +276,9 @@ export default function SettingsPage() {
         initial={{ opacity: 0, y: 20 }}
         animate={{ opacity: 1, y: 0 }}
         transition={{ duration: 0.4, delay: 0.33 }}
+        style={{ marginBottom: '24px' }}
       >
-        <Box sx={{ mb: 3 }}>
         <DeviceTrustManagement />
-        </Box>
       </motion.div>
 
       {/* Biometric Authentication */}

maternal-web/components/settings/DeviceTrustManagement.tsx

@@ -22,6 +22,9 @@ import {
   Divider,
   ToggleButton,
   ToggleButtonGroup,
+  Accordion,
+  AccordionSummary,
+  AccordionDetails,
 } from '@mui/material';
 import {
   Devices,
@@ -32,6 +35,7 @@ import {
   CheckCircle,
   Shield,
   ShieldOutlined,
+  ExpandMore,
 } from '@mui/icons-material';
 import { devicesApi, type DeviceInfo } from '@/lib/api/devices';
 import { motion } from 'framer-motion';
@@ -143,26 +147,41 @@ export function DeviceTrustManagement() {
 
   if (isLoading) {
     return (
-      <Card>
-        <CardContent sx={{ display: 'flex', justifyContent: 'center', py: 4 }}>
-          <CircularProgress />
-        </CardContent>
-      </Card>
+      <Accordion>
+        <AccordionSummary expandIcon={<ExpandMore />}>
+          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, width: '100%' }}>
+            <Shield color="primary" />
+            <Typography variant="h6" fontWeight="600">
+              Trusted Devices
+            </Typography>
+            <CircularProgress size={20} sx={{ ml: 'auto' }} />
+          </Box>
+        </AccordionSummary>
+      </Accordion>
     );
   }
 
   return (
     <>
-      <Card>
-        <CardContent>
-          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, mb: 2 }}>
+      <Accordion>
+        <AccordionSummary
+          expandIcon={<ExpandMore />}
+          sx={{
+            '& .MuiAccordionSummary-content': {
+              margin: '12px 0',
+            },
+          }}
+        >
+          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, width: '100%' }}>
             <Shield color="primary" />
             <Typography variant="h6" fontWeight="600">
-              Device Trust Management
+              Trusted Devices
             </Typography>
-            <Chip label={`${devices.length} devices`} size="small" sx={{ ml: 'auto' }} />
+            <Chip label={`${devices.length}`} size="small" sx={{ ml: 'auto', mr: 1 }} />
           </Box>
+        </AccordionSummary>
 
+        <AccordionDetails>
           <Typography variant="body2" color="text.secondary" sx={{ mb: 3 }}>
             Manage which devices are trusted to access your account. Untrusted devices will require additional verification.
           </Typography>
@@ -278,8 +297,8 @@ export function DeviceTrustManagement() {
               )}
             </>
           )}
-        </CardContent>
-      </Card>
+        </AccordionDetails>
+      </Accordion>
 
       {/* Remove Device Dialog */}
       <Dialog open={removeDialogOpen} onClose={() => setRemoveDialogOpen(false)} maxWidth="sm" fullWidth>

maternal-web/components/settings/SessionsManagement.tsx

@@ -20,6 +20,9 @@ import {
   ListItemSecondaryAction,
   IconButton,
   Divider,
+  Accordion,
+  AccordionSummary,
+  AccordionDetails,
 } from '@mui/material';
 import {
   Devices,
@@ -28,6 +31,7 @@ import {
   Tablet,
   Delete,
   CheckCircle,
+  ExpandMore,
 } from '@mui/icons-material';
 import { sessionsApi, type SessionInfo } from '@/lib/api/sessions';
 import { motion } from 'framer-motion';
@@ -116,26 +120,41 @@ export function SessionsManagement() {
 
   if (isLoading) {
     return (
-      <Card>
-        <CardContent sx={{ display: 'flex', justifyContent: 'center', py: 4 }}>
-          <CircularProgress />
-        </CardContent>
-      </Card>
+      <Accordion>
+        <AccordionSummary expandIcon={<ExpandMore />}>
+          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, width: '100%' }}>
+            <Devices color="primary" />
+            <Typography variant="h6" fontWeight="600">
+              Active Sessions
+            </Typography>
+            <CircularProgress size={20} sx={{ ml: 'auto' }} />
+          </Box>
+        </AccordionSummary>
+      </Accordion>
     );
   }
 
   return (
     <>
-      <Card>
-        <CardContent>
-          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, mb: 2 }}>
+      <Accordion>
+        <AccordionSummary
+          expandIcon={<ExpandMore />}
+          sx={{
+            '& .MuiAccordionSummary-content': {
+              margin: '12px 0',
+            },
+          }}
+        >
+          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, width: '100%' }}>
             <Devices color="primary" />
             <Typography variant="h6" fontWeight="600">
               Active Sessions
             </Typography>
-            <Chip label={`${sessions.length} active`} size="small" sx={{ ml: 'auto' }} />
+            <Chip label={`${sessions.length}`} size="small" sx={{ ml: 'auto', mr: 1 }} />
           </Box>
+        </AccordionSummary>
 
+        <AccordionDetails>
           <Typography variant="body2" color="text.secondary" sx={{ mb: 3 }}>
             Manage your active sessions across different devices. You can revoke access from any device.
           </Typography>
@@ -220,8 +239,8 @@ export function SessionsManagement() {
               )}
             </>
           )}
-        </CardContent>
-      </Card>
+        </AccordionDetails>
+      </Accordion>
 
       {/* Revoke Session Dialog */}
       <Dialog open={revokeDialogOpen} onClose={() => setRevokeDialogOpen(false)} maxWidth="sm" fullWidth>