diff --git a/public/static/style.css b/public/static/style.css
index f4cf7bd..4424a71 100644
--- a/public/static/style.css
+++ b/public/static/style.css
@@ -14,7 +14,8 @@ body {
 
 /* --- Header --- */
 header {
-    margin: 1em;
+    margin: 1rem;
+    padding: 0 1rem;
     display: flex;
     justify-content: space-between;
     align-content: center;
@@ -22,7 +23,7 @@ header {
 }
 
 header h1 {
-    margin: 1em;
+    margin: 1rem;
 }
 
 /* --- Navigation bar --- */
@@ -76,14 +77,15 @@ nav li.nav_current_page a {
 
 /* --- Main section --- */
 main {
-    margin: 2em;
+    margin: 2rem;
 }
 
 /* --- Login page --- */
 main.login_page {
-    margin: 2em;
-    padding: 1em;
+    margin: 2rem;
+    padding: 1rem;
     border: 1px solid #666666;
+    width: 40rem;
 }
 
 /* --- Text and other styling --- */
@@ -101,11 +103,18 @@ a:hover, a:focus {
     text-decoration: underline;
 }
 
+.error_box, .success_box {
+    max-width: 50rem;
+    margin: 1rem 0;
+    padding: 1rem;
+}
+
 .error_box {
     background: #ff4444;
-    max-width: 50em;
-    margin: 1em 0;
-    padding: 1em;
+}
+
+.success_box {
+    background: #00cc00;
 }
 
 .gray {
@@ -131,7 +140,7 @@ button {
 /* --- Tables --- */
 
 table td, table th {
-    padding: 0.25em 0.5em;
+    padding: 0.25rem 0.5rem;
 }
 
 table.bordered_table,
@@ -140,7 +149,7 @@ table.bordered_table td,
 table.bordered_table th {
     border: 1px solid #999999;
     border-collapse: collapse;
-    padding: 0.25em 0.5em;
+    padding: 0.25rem 0.5rem;
 }
 
 .vertical_table_headers th {
@@ -152,13 +161,13 @@ table.bordered_table th {
 .edit_box,
 .confirmation_box {
     border: 1px solid #999999;
-    padding: 1em;
-    margin: 1em 0;
+    padding: 1rem;
+    margin: 1rem 0;
 }
 
 /* --- Detail columns --- */
 input#show_details_checkbox {
-    margin-bottom: 1em;
+    margin-bottom: 1rem;
 }
 
 input#show_details_checkbox:not(:checked) ~ table .detail_column {
diff --git a/src/Dependencies.php b/src/Dependencies.php
index 50c82e1..fc3d767 100644
--- a/src/Dependencies.php
+++ b/src/Dependencies.php
@@ -16,6 +16,7 @@ use MailAccountAdmin\Repositories\DomainRepository;
 use PDO;
 use Psr\Container\ContainerInterface;
 use Slim\Views\Twig;
+use Twig\Extension\CoreExtension as TwigCoreExtension;
 
 class Dependencies
 {
@@ -36,7 +37,17 @@ class Dependencies
             /** @var Settings $settings */
             $settings = $c->get(self::SETTINGS);
 
-            return Twig::create(self::TWIG_TEMPLATE_DIR, $settings->getTwigSettings());
+            // Create Twig view
+            $twig = Twig::create(self::TWIG_TEMPLATE_DIR, $settings->getTwigSettings());
+
+            // Set default date format
+            /** @var TwigCoreExtension $coreExtension */
+            $coreExtension = $twig->getEnvironment()->getExtension(TwigCoreExtension::class);
+            $coreExtension->setDateFormat($settings->getDateFormat());
+            $coreExtension->setTimezone($settings->getTimezone());
+
+            // Return Twig view
+            return $twig;
         });
 
         // Database connection
diff --git a/src/Exceptions/InformationUnknownException.php b/src/Exceptions/InformationUnknownException.php
new file mode 100644
index 0000000..0889af8
--- /dev/null
+++ b/src/Exceptions/InformationUnknownException.php
@@ -0,0 +1,8 @@
+<?php
+declare(strict_types=1);
+
+namespace MailAccountAdmin\Exceptions;
+
+class InformationUnknownException extends AppException
+{
+}
diff --git a/src/Frontend/Accounts/AccountController.php b/src/Frontend/Accounts/AccountController.php
index 1a27498..a7a6c18 100644
--- a/src/Frontend/Accounts/AccountController.php
+++ b/src/Frontend/Accounts/AccountController.php
@@ -5,6 +5,7 @@ namespace MailAccountAdmin\Frontend\Accounts;
 
 use MailAccountAdmin\Common\UserHelper;
 use MailAccountAdmin\Frontend\BaseController;
+use MailAccountAdmin\Models\Account;
 use MailAccountAdmin\Repositories\AccountRepository;
 use MailAccountAdmin\Repositories\AliasRepository;
 use Psr\Http\Message\ResponseInterface as Response;
@@ -25,6 +26,9 @@ class AccountController extends BaseController
         $this->aliasRepository = $aliasRepository;
     }
 
+
+    // -- /accounts - List all accounts
+
     public function showAccounts(Request $request, Response $response): Response
     {
         // Parse query parameters for filters
@@ -39,21 +43,22 @@ class AccountController extends BaseController
         return $this->view->render($response, 'accounts.html.twig', $renderData);
     }
 
+
+    // -- /accounts/{id} - Show account details
+
     public function showAccountDetails(Request $request, Response $response, array $args): Response
     {
         // Parse URL arguments
         $accountId = (int)$args['id'];
 
         // Get account data from database
-        $accountData = $this->accountRepository->fetchAccountById($accountId);
-        $accountUsername = $accountData['username'];
-        $accountData['domain'] = explode('@', $accountUsername, 2)[1];
+        $account = $this->accountRepository->fetchAccountById($accountId);
 
         // Don't display the password hash, but at least the type of hash (used hash algorithm)
-        if ($accountData['password'] === '') {
+        if ($account->getPasswordHash() === '') {
             $passwordHashType = 'empty';
         } else {
-            $passwordHashInfo = password_get_info($accountData['password']);
+            $passwordHashInfo = password_get_info($account->getPasswordHash());
             $passwordHashType = $passwordHashInfo['algoName'] ?? 'unknown';
         }
 
@@ -62,8 +67,8 @@ class AccountController extends BaseController
 
         $renderData = [
             'id' => $accountId,
-            'accountUsername' => $accountUsername,
-            'accountData' => $accountData,
+            'accountUsername' => $account->getUsername(),
+            'account' => $account,
             'passwordHashType' => $passwordHashType,
             'aliases' => $aliases,
         ];
@@ -71,26 +76,27 @@ class AccountController extends BaseController
         return $this->view->render($response, 'account_details.html.twig', $renderData);
     }
 
+
+    // -- /accounts/new - Create new account
+
     public function showAccountCreate(Request $request, Response $response): Response
     {
         return $this->showAccounts($request, $response);
     }
 
+
+    // -- /accounts/{id}/edit - Edit account
+
     public function showAccountEdit(Request $request, Response $response, array $args): Response
     {
         // Parse URL arguments
         $accountId = (int)$args['id'];
 
         // Get account data from database
-        $accountData = $this->accountRepository->fetchAccountById($accountId);
+        $account = $this->accountRepository->fetchAccountById($accountId);
 
-        $renderData = [
-            'id' => $accountId,
-            'accountUsername' => $accountData['username'],
-            'accountData' => $accountData,
-        ];
-
-        return $this->view->render($response, 'account_edit.html.twig', $renderData);
+        // Render page
+        return $this->renderEditPage($response, $account);
     }
 
     public function editAccount(Request $request, Response $response, array $args): Response
@@ -100,18 +106,31 @@ class AccountController extends BaseController
         return $this->showAccountEdit($request, $response, $args);
     }
 
+    private function renderEditPage(Response $response, Account $account, array $extraRenderData = []): Response
+    {
+        $renderData = [
+            'id' => $account->getId(),
+            'accountUsername' => $account->getUsername(),
+            'account' => $account,
+        ];
+
+        return $this->view->render($response, 'account_edit.html.twig', array_merge($renderData, $extraRenderData));
+    }
+
+    // -- /accounts/{id}/delete - Delete account
+
     public function showAccountDelete(Request $request, Response $response, array $args): Response
     {
         // Parse URL arguments
         $accountId = (int)$args['id'];
 
         // Get account data and list of aliases from database
-        $accountData = $this->accountRepository->fetchAccountById($accountId);
+        $account = $this->accountRepository->fetchAccountById($accountId);
         $aliases = $this->aliasRepository->fetchAliasesForUserId($accountId);
 
         $renderData = [
             'id' => $accountId,
-            'accountUsername' => $accountData['username'],
+            'accountUsername' => $account->getUsername(),
             'aliases' => $aliases,
         ];
 
diff --git a/src/Models/Account.php b/src/Models/Account.php
new file mode 100644
index 0000000..472e576
--- /dev/null
+++ b/src/Models/Account.php
@@ -0,0 +1,138 @@
+<?php
+declare(strict_types=1);
+
+namespace MailAccountAdmin\Models;
+
+use DateTimeImmutable;
+use MailAccountAdmin\Exceptions\InformationUnknownException;
+
+class Account
+{
+    /** @var int */
+    private $id;
+    /** @var string */
+    private $username;
+    /** @var string */
+    private $passwordHash;
+    /** @var bool */
+    private $active;
+    /** @var string */
+    private $homeDir;
+    /** @var string */
+    private $memo;
+    /** @var DateTimeImmutable */
+    private $createdAt;
+    /** @var DateTimeImmutable */
+    private $modifiedAt;
+
+    // Extra data that is not part of the data model
+
+    // Domain (extracted from username)
+    /** @var string */
+    private $domain;
+
+    // Number of aliases (not always available)
+    /** @var int|null */
+    private $aliasCount;
+
+    private function __construct(int $id, string $username, string $passwordHash, bool $active, string $homeDir, string $memo,
+                                 DateTimeImmutable $createdAt, DateTimeImmutable $modifiedAt)
+    {
+        $this->id = $id;
+        $this->username = $username;
+        $this->passwordHash = $passwordHash;
+        $this->active = $active;
+        $this->homeDir = $homeDir;
+        $this->memo = $memo;
+        $this->createdAt = $createdAt;
+        $this->modifiedAt = $modifiedAt;
+
+        // Extract domain from username
+        $this->domain = explode('@', $this->username, 2)[1];
+    }
+
+    public static function createFromArray(array $data): self
+    {
+        $account = new self(
+            (int)$data['user_id'],
+            $data['username'],
+            $data['password'],
+            $data['is_active'] === '1',
+            $data['home_dir'],
+            $data['memo'] !== null ? $data['memo'] : '',
+            new DateTimeImmutable($data['created_at']),
+            new DateTimeImmutable($data['modified_at']),
+        );
+
+        if (isset($data['alias_count'])) {
+            $account->setAliasCount((int)$data['alias_count']);
+        }
+        return $account;
+    }
+
+    public function getId(): int
+    {
+        return $this->id;
+    }
+
+    public function getUsername(): string
+    {
+        return $this->username;
+    }
+
+    public function getPasswordHash(): string
+    {
+        return $this->passwordHash;
+    }
+
+    public function isActive(): bool
+    {
+        return $this->active;
+    }
+
+    public function getHomeDir(): string
+    {
+        return $this->homeDir;
+    }
+
+    public function getMemo(): string
+    {
+        return $this->memo;
+    }
+
+    public function getCreatedAt(): DateTimeImmutable
+    {
+        return $this->createdAt;
+    }
+
+    public function getModifiedAt(): DateTimeImmutable
+    {
+        return $this->modifiedAt;
+    }
+
+
+    // Getters and setters for extra data that is not part of the data model
+
+    public function getDomain(): string
+    {
+        return $this->domain;
+    }
+
+    public function hasAliasCount(): bool
+    {
+        return $this->aliasCount !== null;
+    }
+
+    public function getAliasCount(): int
+    {
+        if ($this->aliasCount === null) {
+            throw new InformationUnknownException('Alias count is not set on this object.');
+        }
+        return $this->aliasCount;
+    }
+
+    public function setAliasCount(int $newAliasCount): void
+    {
+        $this->aliasCount = $newAliasCount;
+    }
+}
diff --git a/src/Repositories/AccountRepository.php b/src/Repositories/AccountRepository.php
index a506447..03a6066 100644
--- a/src/Repositories/AccountRepository.php
+++ b/src/Repositories/AccountRepository.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace MailAccountAdmin\Repositories;
 
 use MailAccountAdmin\Exceptions\AccountNotFoundException;
+use MailAccountAdmin\Models\Account;
 use PDO;
 
 class AccountRepository extends BaseRepository
@@ -31,10 +32,17 @@ class AccountRepository extends BaseRepository
 
         $statement = $this->pdo->prepare($query);
         $statement->execute($queryParams);
-        return $statement->fetchAll(PDO::FETCH_ASSOC);
+        $rows = $statement->fetchAll(PDO::FETCH_ASSOC);
+
+        // Create Account models from rows
+        $accountList = [];
+        foreach ($rows as $row) {
+            $accountList[] = Account::createFromArray($row);
+        }
+        return $accountList;
     }
 
-    public function fetchAccountById(int $accountId): array
+    public function fetchAccountById(int $accountId): Account
     {
         $statement = $this->pdo->prepare('SELECT * FROM mail_users WHERE user_id = :user_id LIMIT 1');
         $statement->execute(['user_id' => $accountId]);
@@ -43,6 +51,7 @@ class AccountRepository extends BaseRepository
             throw new AccountNotFoundException("Account with user ID '$accountId' was not found.");
         }
 
-        return $statement->fetch(PDO::FETCH_ASSOC);
+        $row = $statement->fetch(PDO::FETCH_ASSOC);
+        return Account::createFromArray($row);
     }
 }
diff --git a/src/Settings.php b/src/Settings.php
index ca111a0..1aecf4b 100644
--- a/src/Settings.php
+++ b/src/Settings.php
@@ -10,10 +10,23 @@ class Settings
         return getenv('APP_DEBUG') === 'true';
     }
 
+    public function getTimezone(): string
+    {
+        return 'Europe/Berlin';
+    }
+
+    public function getDateFormat(): string
+    {
+        // Default date format (https://www.php.net/manual/en/datetime.format.php)
+        // RFC 2822 formatted date (Thu, 21 Dec 2000 16:01:07 +0200)
+        return 'r';
+    }
+
     public function getTwigSettings(): array
     {
         return [
             'cache' => getenv('TWIG_CACHE_DIR') ?: false,
+            'debug' => $this->isDebugMode(),
             'strict_variables' => getenv('TWIG_STRICT') === 'true',
         ];
     }
diff --git a/templates/account_details.html.twig b/templates/account_details.html.twig
index ec702fe..642f3aa 100644
--- a/templates/account_details.html.twig
+++ b/templates/account_details.html.twig
@@ -18,15 +18,15 @@
     <table class="bordered_table vertical_table_headers">
         <tr>
             <th style="min-width: 10em">User ID</th>
-            <td style="min-width: 20em">{{ accountData['user_id'] }}</td>
+            <td style="min-width: 20em">{{ account.getId() }}</td>
         </tr>
         <tr>
             <th>Username</th>
-            <td>{{ accountData['username'] }}</td>
+            <td>{{ account.getUsername() }}</td>
         </tr>
         <tr>
             <th>Domain</th>
-            <td><a href="/accounts?domain={{ accountData['domain'] | escape('url') }}">{{ accountData['domain'] }}</a></td>
+            <td><a href="/accounts?domain={{ account.getDomain() | escape('url') }}">{{ account.getDomain() }}</a></td>
         </tr>
         <tr>
             <th>Password</th>
@@ -42,23 +42,23 @@
         </tr>
         <tr>
             <th>Status</th>
-            <td>{{ accountData['is_active'] == '1' ? '<span class="green">Active</span>' : '<span class="red">Inactive</span>' }}</td>
+            <td>{{ account.isActive() ? '<span class="green">Active</span>' : '<span class="red">Inactive</span>' }}</td>
         </tr>
         <tr>
             <th>Home directory</th>
-            <td><span class="gray">/srv/vmail/</span>{{ accountData['home_dir'] }}</td>
+            <td><span class="gray">/srv/vmail/</span>{{ account.getHomeDir() }}</td>
         </tr>
         <tr>
             <th>Admin memo</th>
-            <td>{{ accountData['memo'] | nl2br }}</td>
+            <td>{{ account.getMemo() | nl2br }}</td>
         </tr>
         <tr>
             <th>Created at</th>
-            <td>{{ accountData['created_at'] }}</td>
+            <td>{{ account.getCreatedAt() | date }}</td>
         </tr>
         <tr>
             <th>Last modified at</th>
-            <td>{{ accountData['modified_at'] }}</td>
+            <td>{{ account.getModifiedAt() | date }}</td>
         </tr>
     </table>
 
diff --git a/templates/account_edit.html.twig b/templates/account_edit.html.twig
index 4667eef..3d48be6 100644
--- a/templates/account_edit.html.twig
+++ b/templates/account_edit.html.twig
@@ -28,7 +28,7 @@
             <table>
                 <tr>
                     <td>Current username:</td>
-                    <td>{{ accountData['username'] }}</td>
+                    <td>{{ account.getUsername() }}</td>
                 </tr>
                 <tr>
                     <td><label for="edit_username">New username:</label></td>
@@ -67,13 +67,13 @@
             <table>
                 <tr>
                     <td>Current status:</td>
-                    <td>{{ accountData['is_active'] == '1' ? '<span class="green">Active</span>' : '<span class="red">Inactive</span>' }}</td>
+                    <td>{{ account.isActive() ? '<span class="green">Active</span>' : '<span class="red">Inactive</span>' }}</td>
                 </tr>
                 <tr>
                     <td>New status:</td>
                     <td>
                         <label>
-                            <input type="checkbox" name="is_active" {{ accountData['is_active'] == '1' ? 'checked' : '' }}/> Active
+                            <input type="checkbox" name="is_active" {{ account.isActive() ? 'checked' : '' }}/> Active
                         </label>
                     </td>
                 </tr>
@@ -87,7 +87,7 @@
             <table>
                 <tr>
                     <td>Current home directory:</td>
-                    <td><span class="gray">/srv/vmail/</span>{{ accountData['home_dir'] }}</td>
+                    <td><span class="gray">/srv/vmail/</span>{{ account.getHomeDir() }}</td>
                 </tr>
                 <tr>
                     <td><label for="edit_home_dir">New home directory:</label></td>
@@ -104,7 +104,7 @@
             <table>
                 <tr>
                     <td><label for="edit_memo">Admin memo:</label></td>
-                    <td><textarea id="edit_memo" name="memo" style="min-width: 40em;">{{ accountData['memo'] }}</textarea></td>
+                    <td><textarea id="edit_memo" name="memo" style="min-width: 40em;">{{ account.getMemo() }}</textarea></td>
                 </tr>
             </table>
         </div>
diff --git a/templates/accounts.html.twig b/templates/accounts.html.twig
index 3c9ae7f..caa2883 100644
--- a/templates/accounts.html.twig
+++ b/templates/accounts.html.twig
@@ -37,15 +37,15 @@
         </tr>
         {% if accountList %}
             {% for account in accountList -%}
-                <tr{% if account['is_active'] != 1 %} class="inactive"{% endif %}>
-                    <td><a href="/accounts/{{ account['user_id'] }}">{{ account['username'] }}</a></td>
-                    <td><a href="/accounts?domain={{ account['domain'] }}">{{ account['domain'] }}</a></td>
-                    <td>{{ account['alias_count'] }}</td>
-                    <td>{{ account['is_active'] == 1 ? 'Yes' : 'No' }}</td>
-                    <td class="detail_column"><span class="gray">vmail/</span>{{ account['home_dir'] }}</td>
-                    <td class="detail_column">{{ account['memo'] }}</td>
-                    <td>{{ account['created_at'] }}</td>
-                    <td class="detail_column">{{ account['modified_at'] }}</td>
+                <tr{% if not account.isActive() %} class="inactive"{% endif %}>
+                    <td><a href="/accounts/{{ account.getId() }}">{{ account.getUsername() }}</a></td>
+                    <td><a href="/accounts?domain={{ account.getDomain() }}">{{ account.getDomain() }}</a></td>
+                    <td>{{ account.getAliasCount() }}</td>
+                    <td>{{ account.isActive() ? 'Yes' : 'No' }}</td>
+                    <td class="detail_column"><span class="gray">vmail/</span>{{ account.getHomeDir() }}</td>
+                    <td class="detail_column">{{ account.getMemo() }}</td>
+                    <td>{{ account.getCreatedAt() | date }}</td>
+                    <td class="detail_column">{{ account.getModifiedAt() | date }}</td>
                 </tr>
             {% endfor %}
         {% else %}