diff --git a/templates/auth/login.html b/templates/auth/login.html
index e69de29..35adec8 100644
--- a/templates/auth/login.html
+++ b/templates/auth/login.html
@@ -0,0 +1,23 @@
+{% extends "base.html" %}
+{% block title %}Log In{% endblock %}
+{% block content %}
+  <h2>Log In</h2>
+  <form method="POST" novalidate class="col-md-6">
+    {{ form.hidden_tag() }}
+    <div class="mb-3">
+      {{ form.email.label(class="form-label") }}
+      {{ form.email(class="form-control") }}
+      {% for error in form.email.errors %}<div class="text-danger small">{{ error }}</div>{% endfor %}
+    </div>
+    <div class="mb-3">
+      {{ form.password.label(class="form-label") }}
+      {{ form.password(class="form-control") }}
+      {% for error in form.password.errors %}<div class="text-danger small">{{ error }}</div>{% endfor %}
+    </div>
+    <div class="form-check mb-3">
+      {{ form.remember_me(class="form-check-input") }}
+      {{ form.remember_me.label(class="form-check-label") }}
+    </div>
+    {{ form.submit(class="btn btn-primary") }}
+  </form>
+{% endblock %}
diff --git a/templates/auth/register.html b/templates/auth/register.html
index e69de29..86d6e1c 100644
--- a/templates/auth/register.html
+++ b/templates/auth/register.html
@@ -0,0 +1,29 @@
+{% extends "base.html" %}
+{% block title %}Register{% endblock %}
+{% block content %}
+  <h2>Create Account</h2>
+  <form method="POST" novalidate class="col-md-6">
+    {{ form.hidden_tag() }}
+    <div class="mb-3">
+      {{ form.username.label(class="form-label") }}
+      {{ form.username(class="form-control") }}
+      {% for error in form.username.errors %}<div class="text-danger small">{{ error }}</div>{% endfor %}
+    </div>
+    <div class="mb-3">
+      {{ form.email.label(class="form-label") }}
+      {{ form.email(class="form-control") }}
+      {% for error in form.email.errors %}<div class="text-danger small">{{ error }}</div>{% endfor %}
+    </div>
+    <div class="mb-3">
+      {{ form.password.label(class="form-label") }}
+      {{ form.password(class="form-control") }}
+      {% for error in form.password.errors %}<div class="text-danger small">{{ error }}</div>{% endfor %}
+    </div>
+    <div class="mb-3">
+      {{ form.confirm_password.label(class="form-label") }}
+      {{ form.confirm_password(class="form-control") }}
+      {% for error in form.confirm_password.errors %}<div class="text-danger small">{{ error }}</div>{% endfor %}
+    </div>
+    {{ form.submit(class="btn btn-primary") }}
+  </form>
+{% endblock %}
diff --git a/templates/base.html b/templates/base.html
index e69de29..92acdea 100644
--- a/templates/base.html
+++ b/templates/base.html
@@ -0,0 +1,37 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>{% block title %}MyApp{% endblock %}</title>
+  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css">
+</head>
+<body>
+  <nav class="navbar navbar-expand-lg navbar-light bg-light mb-4">
+    <div class="container">
+      <a class="navbar-brand" href="{{ url_for('main.index') }}">MyApp</a>
+      <div class="d-flex gap-2">
+        {% if current_user.is_authenticated %}
+          <span class="navbar-text">Hi, {{ current_user.username }}</span>
+          <a class="btn btn-outline-secondary btn-sm" href="{{ url_for('auth.logout') }}">Log out</a>
+        {% else %}
+          <a class="btn btn-outline-primary btn-sm" href="{{ url_for('auth.login') }}">Log in</a>
+          <a class="btn btn-primary btn-sm" href="{{ url_for('auth.register') }}">Register</a>
+        {% endif %}
+      </div>
+    </div>
+  </nav>
+
+  <div class="container">
+    {% with messages = get_flashed_messages(with_categories=true) %}
+      {% if messages %}
+        {% for category, message in messages %}
+          <div class="alert alert-{{ category }}">{{ message }}</div>
+        {% endfor %}
+      {% endif %}
+    {% endwith %}
+
+    {% block content %}{% endblock %}
+  </div>
+</body>
+</html>
diff --git a/templates/index.html b/templates/index.html
index e69de29..dc58f49 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -0,0 +1,9 @@
+{% extends "base.html" %}
+{% block title %}Home{% endblock %}
+{% block content %}
+  <h1>Welcome{% if current_user.is_authenticated %}, {{ current_user.username }}{% endif %}!</h1>
+  {% if not current_user.is_authenticated %}
+    <p>Please <a href="{{ url_for('auth.login') }}">log in</a> or
+       <a href="{{ url_for('auth.register') }}">create an account</a>.</p>
+  {% endif %}
+{% endblock %}
