diff --git a/content/math/_index.md b/content/math/_index.md
index 18b5712..b51abb5 100644
--- a/content/math/_index.md
+++ b/content/math/_index.md
@@ -1,6 +1,6 @@
 +++
-title = "Hong Kong Mathematics"
-description = "DSE Compulsory Part mathematics — Number & Algebra, Measures Shape & Space, and Data Handling."
-template = "math/book.html"
+title = "Mathematics"
+description = "Browse mathematics chapters in the curriculum catalog."
+template = "math-redirect.html"
 sort_by = "weight"
 +++
diff --git a/content/math/quadratic-equations/_index.md b/content/math/quadratic-equations/_index.md
index b8b4d20..cd595e0 100644
--- a/content/math/quadratic-equations/_index.md
+++ b/content/math/quadratic-equations/_index.md
@@ -1,6 +1,6 @@
 +++
 title = "Quadratic equations"
-description = "The discriminant, nature of roots, and the graph of y = ax² + bx + c — DSE Compulsory Part."
+description = "The discriminant, nature of roots, and the graph of y = ax² + bx + c."
 template = "math/chapter.html"
 weight = 1
 [extra]
diff --git a/data/math-dse-curriculum.json b/data/math-curriculum.json
similarity index 90%
rename from data/math-dse-curriculum.json
rename to data/math-curriculum.json
index 13eb276..23e089c 100644
--- a/data/math-dse-curriculum.json
+++ b/data/math-curriculum.json
@@ -1,7 +1,7 @@
 {
-  "title": "Hong Kong Mathematics",
-  "subtitle": "DSE Compulsory Part (S4–S6)",
-  "intro": "Structured around the three core strands of the Hong Kong mathematics curriculum. Chapters marked as available can be read now; others are on the roadmap.",
+  "title": "Mathematics",
+  "subtitle": "Secondary level (S4–S6)",
+  "intro": "Structured around three core strands. Chapters marked as available can be read now; others are on the roadmap.",
   "strands": [
     {
       "id": "number-algebra",
diff --git a/spec.md b/spec.md
index cea5fb9..8b13e74 100644
--- a/spec.md
+++ b/spec.md
@@ -12,4 +12,4 @@ we don't i18n. i18n will be solved in future by big companies.
 
 search is supported by pagefind.
 
-we have a catalog of subjects. Each subject will have chapters. Each chapters can be labelled (multiple) cirriculum. E.g. DSE, IB, A level. so that user knows if a chapter is needed in a cirriculum. Each subject should show all chapters by default (all cirriculum). chapters should be sequential in a tree structure. users can filter by themselves. 
\ No newline at end of file
+we have a catalog of subjects. Each subject will have chapters. Each chapters can be labelled (multiple) cirriculum. E.g. DSE, IB, A level. so that user knows if a chapter is needed in a cirriculum. Each subject should show all chapters by default (all cirriculum). chapters should be sequential in a tree structure. users can filter by themselves. in the chapter we don't specify or mention the cirriculum anymore.
\ No newline at end of file
diff --git a/static/_redirects b/static/_redirects
new file mode 100644
index 0000000..66d1e0f
--- /dev/null
+++ b/static/_redirects
@@ -0,0 +1,2 @@
+/math/   /catalog/?subject=math   301
+/math    /catalog/?subject=math   301
diff --git a/themes/openfreebooks/templates/catalog.html b/themes/openfreebooks/templates/catalog.html
index 4dbe88a..0cdca4d 100644
--- a/themes/openfreebooks/templates/catalog.html
+++ b/themes/openfreebooks/templates/catalog.html
@@ -7,7 +7,7 @@
 
 {% block content %}
 {% set catalog = load_data(path="data/catalog.json", format="json") %}
-{% set math = load_data(path="data/math-dse-curriculum.json", format="json") %}
+{% set math_catalog = load_data(path="data/math-curriculum.json", format="json") %}
 <script id="catalog-data" type="application/json">
 {
   "title": {{ catalog.title | json_encode() | safe }},
@@ -18,7 +18,7 @@
     {
       "id": {{ subject.id | json_encode() | safe }},
       "name": {{ subject.name | json_encode() | safe }},
-      "strands": {% if subject.id == "math" %}{{ math.strands | json_encode() | safe }}{% else %}[]{% endif %}
+      "strands": {% if subject.id == "math" %}{{ math_catalog.strands | json_encode() | safe }}{% else %}[]{% endif %}
     }{% if not loop.last %},{% endif %}
     {% endfor %}
   ]
@@ -32,7 +32,7 @@
       <p>{{ catalog.subtitle }}</p>
       <p>
         JavaScript is required for the interactive catalog. You can read
-        <a href="{{ get_url(path='/math/') | safe }}">Hong Kong Mathematics</a> directly.
+        <a href="{{ get_url(path='/catalog/') | safe }}?subject=math">Mathematics in the catalog</a> directly.
       </p>
     </div>
   </div>
diff --git a/themes/openfreebooks/templates/index.html b/themes/openfreebooks/templates/index.html
index bdae40a..70ef619 100644
--- a/themes/openfreebooks/templates/index.html
+++ b/themes/openfreebooks/templates/index.html
@@ -49,10 +49,10 @@
     <h2 class="section-title">Browse by subject</h2>
     <div class="work-grid" data-scroll-reveal>
       <article class="work-card work-card--link" data-scroll-reveal-card>
-        <a class="work-card__anchor" href="{{ get_url(path='/math/') | safe }}">
+        <a class="work-card__anchor" href="{{ get_url(path='/catalog/') | safe }}?subject=math">
           <h3>Mathematics</h3>
-          <p class="card-subtitle">DSE Compulsory — live</p>
-          <p>Hong Kong secondary mathematics: three curriculum strands, starting with quadratic equations.</p>
+          <p class="card-subtitle">Live chapters</p>
+          <p>Three strands from number and algebra through data handling — starting with quadratic equations.</p>
         </a>
       </article>
       <article class="work-card" data-scroll-reveal-card>
@@ -81,10 +81,10 @@
     <h2 class="section-title">Featured books</h2>
     <div class="work-grid" data-scroll-reveal>
       <article class="work-card work-card--link" data-scroll-reveal-card>
-        <a class="work-card__anchor" href="{{ get_url(path='/math/') | safe }}">
-          <h3>Hong Kong Mathematics</h3>
-          <p class="card-subtitle">DSE Compulsory Part</p>
-          <p>Number &amp; Algebra, Measures Shape &amp; Space, and Data Handling — with an interactive quadratic explorer.</p>
+        <a class="work-card__anchor" href="{{ get_url(path='/math/quadratic-equations/') | safe }}">
+          <h3>Quadratic equations</h3>
+          <p class="card-subtitle">Featured chapter</p>
+          <p>Discriminant, nature of roots, and an interactive graph explorer — read in the browser.</p>
         </a>
       </article>
       <article class="work-card" data-scroll-reveal-card>
diff --git a/themes/openfreebooks/templates/math-redirect.html b/themes/openfreebooks/templates/math-redirect.html
new file mode 100644
index 0000000..e85dc05
--- /dev/null
+++ b/themes/openfreebooks/templates/math-redirect.html
@@ -0,0 +1,27 @@
+{% extends "base.html" %}
+
+{% block title %}{{ section.title }} | {{ config.extra.site_title }}{% endblock title %}
+{% block meta_description %}
+<meta name="description" content="Redirecting to the curriculum catalog." />
+{% endblock meta_description %}
+
+{% block extra_head %}
+{% set catalog_url = get_url(path="/catalog/") ~ "?subject=math" %}
+<meta http-equiv="refresh" content="0; url={{ catalog_url | safe }}" />
+<link rel="canonical" href="{{ catalog_url | safe }}" />
+{% endblock extra_head %}
+
+{% block content %}
+{% set catalog_url = get_url(path="/catalog/") ~ "?subject=math" %}
+<section class="catalog-page">
+  <div class="container">
+    <p class="section-kicker">Redirecting</p>
+    <h1 class="section-title">{{ section.title }}</h1>
+    <p>
+      The mathematics catalog has moved.
+      <a href="{{ catalog_url | safe }}">Continue to the catalog</a>
+      if you are not redirected automatically.
+    </p>
+  </div>
+</section>
+{% endblock content %}
diff --git a/themes/openfreebooks/templates/math/book.html b/themes/openfreebooks/templates/math/book.html
deleted file mode 100644
index 9503db8..0000000
--- a/themes/openfreebooks/templates/math/book.html
+++ /dev/null
@@ -1,51 +0,0 @@
-{% extends "base.html" %}
-
-{% block title %}{{ section.title }} | {{ config.extra.site_title }}{% endblock title %}
-{% block meta_description %}
-<meta name="description" content="{{ section.description | default(value=config.description) }}" />
-{% endblock meta_description %}
-
-{% block content %}
-{% set curriculum = load_data(path="data/math-dse-curriculum.json", format="json") %}
-<section class="book-page">
-  <div class="container">
-    <nav class="book-breadcrumb" aria-label="Breadcrumb">
-      <a href="{{ get_url(path='/') | safe }}">Home</a>
-      <span class="book-breadcrumb__sep" aria-hidden="true">/</span>
-      <span aria-current="page">{{ curriculum.title }}</span>
-    </nav>
-
-    <header class="book-header">
-      <p class="section-kicker">Mathematics</p>
-      <h1 class="section-title">{{ curriculum.title }}</h1>
-      <p class="book-subtitle">{{ curriculum.subtitle }}</p>
-      <p class="book-intro">{{ curriculum.intro }}</p>
-    </header>
-
-    <div class="book-strands">
-      {% for strand in curriculum.strands %}
-      <section class="book-strand" aria-labelledby="strand-{{ strand.id }}">
-        <h2 id="strand-{{ strand.id }}" class="book-strand__title">{{ strand.title }}</h2>
-        <ul class="book-chapter-list">
-          {% for chapter in strand.chapters %}
-          <li class="book-chapter-item{% if chapter.status != 'live' %} book-chapter-item--planned{% endif %}">
-            {% if chapter.status == 'live' %}
-            <a class="book-chapter-link" href="{{ get_url(path='math/' ~ chapter.slug ~ '/') | safe }}">
-              <span class="book-chapter-link__title">{{ chapter.title }}</span>
-              <span class="book-chapter-badge book-chapter-badge--live">Available</span>
-            </a>
-            {% else %}
-            <span class="book-chapter-link book-chapter-link--disabled">
-              <span class="book-chapter-link__title">{{ chapter.title }}</span>
-              <span class="book-chapter-badge book-chapter-badge--planned">Coming soon</span>
-            </span>
-            {% endif %}
-          </li>
-          {% endfor %}
-        </ul>
-      </section>
-      {% endfor %}
-    </div>
-  </div>
-</section>
-{% endblock content %}
diff --git a/themes/openfreebooks/templates/math/chapter.html b/themes/openfreebooks/templates/math/chapter.html
index 0a52a74..1e42d77 100644
--- a/themes/openfreebooks/templates/math/chapter.html
+++ b/themes/openfreebooks/templates/math/chapter.html
@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}{{ section.title }} | Hong Kong Mathematics | {{ config.extra.site_title }}{% endblock title %}
+{% block title %}{{ section.title }} | Mathematics | {{ config.extra.site_title }}{% endblock title %}
 {% block meta_description %}
 <meta name="description" content="{{ section.description | default(value=config.description) }}" />
 {% endblock meta_description %}
@@ -10,13 +10,14 @@
 {% endblock extra_head %}
 
 {% block content %}
-{% set curriculum = load_data(path="data/math-dse-curriculum.json", format="json") %}
+{% set math_catalog = load_data(path="data/math-curriculum.json", format="json") %}
+{% set catalog_math_url = get_url(path="/catalog/") ~ "?subject=math" %}
 <section class="book-page book-page--chapter">
   <div class="container">
     <nav class="book-breadcrumb" aria-label="Breadcrumb">
       <a href="{{ get_url(path='/') | safe }}">Home</a>
       <span class="book-breadcrumb__sep" aria-hidden="true">/</span>
-      <a href="{{ get_url(path='/math/') | safe }}">{{ curriculum.title }}</a>
+      <a href="{{ catalog_math_url | safe }}">{{ math_catalog.title }}</a>
       <span class="book-breadcrumb__sep" aria-hidden="true">/</span>
       <span aria-current="page">{{ section.title }}</span>
     </nav>
@@ -33,7 +34,6 @@
       {% if section.extra.chapter_id == "quadratic-equations" %}
       {% include "partials/math/quadratic-equations-content.html" %}
       <div id="quadratic-explorer" class="math-widget-mount"></div>
-      {% include "partials/math/quadratic-equations-dse-callout.html" %}
       {% endif %}
     </article>
   </div>
diff --git a/themes/openfreebooks/templates/partials/math/quadratic-equations-content.html b/themes/openfreebooks/templates/partials/math/quadratic-equations-content.html
index 284b0c6..c4d279c 100644
--- a/themes/openfreebooks/templates/partials/math/quadratic-equations-content.html
+++ b/themes/openfreebooks/templates/partials/math/quadratic-equations-content.html
@@ -1,7 +1,7 @@
 <div class="book-prose">
   <p>
     A quadratic equation in one unknown has the form \(ax^2 + bx + c = 0\), where
-    \(a \neq 0\). On the DSE Compulsory Part you solve these by factorisation, the quadratic
+    \(a \neq 0\). You can solve these by factorisation, the quadratic
     formula, or by reading information from the graph of \(y = ax^2 + bx + c\).
   </p>
 
diff --git a/themes/openfreebooks/templates/partials/math/quadratic-equations-dse-callout.html b/themes/openfreebooks/templates/partials/math/quadratic-equations-dse-callout.html
deleted file mode 100644
index 519e6c9..0000000
--- a/themes/openfreebooks/templates/partials/math/quadratic-equations-dse-callout.html
+++ /dev/null
@@ -1,9 +0,0 @@
-<aside class="book-callout book-callout--dse" role="note">
-  <p class="book-callout__label">DSE note — Foundation vs Non-foundation</p>
-  <p>
-    For a maximum grade around <strong>Level 4</strong>, focus on solving quadratics,
-    interpreting \(\Delta\), and linking graphs to equations (Foundation topics). Candidates aiming at
-    <strong>Level 5*</strong> and above also need fluency with reverse-engineering: given the nature of
-    roots, solve inequalities such as \(\Delta \geq 0\) for an unknown constant.
-  </p>
-</aside>