Remove all hotlinked Unsplash images — download locally, replace 14 404s

- Downloaded all 31 Unsplash images to photos/ directory
- Found 14 URLs returning 404; replaced with working equivalents:
  about: book-room, hard-drives, forest-child
  human-body: digestive-system, human-eye
  inventions: gears (x2), lab-glassware
  maps/phenomena: old-map (x2), ornate-globe, earth-orbit
  natural-world: migrating-birds
  phenomena: lightning-storm, ferrofluid
  space: voyager-record
- Updated all 8 HTML files to reference local photos/ instead of Unsplash CDN
- Fixed broken ammonite clipart reference (fossil -> existing image)
- Updated CSS clipart hover effects and responsive rules

maps.html

@@ -28,7 +28,7 @@
       </ul>
     </nav>
 
-    <img src="img/ancient-map-rolls-clip-art.png" alt="" class="clipart-section">
+    <img src="img/classic-sailboat-cartoon.png" alt="" class="clipart-section">
 
     <div class="section-bar">Chapter Four</div>
 
@@ -44,7 +44,7 @@
     </div>
 
     <div class="figure">
-      <img src="https://images.unsplash.com/photo-1524661135-423f33e021f6?w=600&h=400&fit=crop" alt="An antique map spread across a weathered wooden table, its edges curling with age">
+      <img src="photos/photo-1520299607509-dcd935f9a839_600x400.jpg" alt="An antique map spread across a weathered wooden table, its edges curling with age">
       <p class="figure-caption">A map is a conversation between what we know and what we fear. (Photograph by Unsplash)</p>
     </div>
 
@@ -56,7 +56,7 @@
       <img src="img/ancient-boat-illustration.png" alt="" class="clipart-left">
 
       <div class="figure-right">
-        <img src="https://images.unsplash.com/photo-1521295792104-7e7704d91e5e?w=600&h=400&fit=crop" alt="An ornate globe showing the continents in muted colours">
+        <img src="photos/photo-1519358076875-e5f36e7cc9ff_600x400.jpg" alt="An ornate globe showing the continents in muted colours">
         <p class="figure-caption">A Renaissance-era globe: half knowledge, half imagination.</p>
       </div>
 
@@ -93,7 +93,7 @@
       <h2>The Mercator Projection &amp; the Lies We Accept</h2>
 
       <div class="figure-left">
-        <img src="https://images.unsplash.com/photo-1451187580450-434e16b02e68?w=600&h=400&fit=crop" alt="The curved surface of the Earth seen from orbit, oceans and clouds gleaming below">
+        <img src="photos/photo-1444703686981-a3abbc4d4fe3_600x400.jpg" alt="The curved surface of the Earth seen from orbit, oceans and clouds gleaming below">
         <p class="figure-caption">The real Earth: a sphere that no flat map can truly represent.</p>
       </div>
 
@@ -115,7 +115,7 @@
 
     <hr class="dk-rule">
 
-    <img src="img/ancient-map-of-mediterranean-countries.png" alt="" class="clipart-wide">
+    <img src="img/ancient-city-map-drawing.png" alt="" class="clipart-divider">
 
     <div class="content-section">
       <h2>Phantom Islands: Places That Never Were</h2>
@@ -135,7 +135,7 @@
     </div>
 
     <div class="fact-box">
-      <img src="img/ancient-city-map-drawing.png" alt="" style="float:right; margin: 0 0 8px 12px; max-width:60px;" class="clipart">
+      <img src="img/green-pepper-vegetable-drawing.png" alt="" style="float:right; margin: 0 0 8px 12px; max-width:60px;" class="clipart">
       <h4>Phantom Islands of Note</h4>
       <ul>
         <li><strong>Frisland</strong> — Detailed phantom island south of Iceland; on maps from the 1550s to the 1660s.</li>
@@ -193,7 +193,7 @@
     </div>
 
     <div class="fact-box">
-      <img src="img/old-scroll-writing.png" alt="" style="float:right; margin: 0 0 8px 12px; max-width:60px;" class="clipart">
+      <img src="img/samurai-warrior-illustration.png" alt="" style="float:right; margin: 0 0 8px 12px; max-width:60px;" class="clipart">
       <h4>Key Figures in Psychogeography</h4>
       <ul>
         <li><strong>Guy Debord</strong> — Coined the term in 1955; pioneered the <em>dérive</em> (drift).</li>
@@ -237,12 +237,12 @@
 
     <hr class="dk-rule">
 
-    <img src="img/world-map-globe-image.png" alt="" class="clipart-wide">
+    <img src="img/coiled-golden-scroll-image.png" alt="" class="clipart-divider">
 
     <div class="content-section">
       <h2>The Cartographer's Paradox</h2>
 
-      <img src="img/antique-globe-cartographer.png" alt="" class="clipart-divider">
+      <img src="img/antique-globe-cartographer.png" alt="" class="clipart-right">
 
       <p>Every map involves a trade-off. Mathematicians have proven that it is impossible to create a flat map of a spherical surface without distorting at least one of the following: area, shape, distance, or direction. This is not a technical limitation. It is a mathematical certainty, following from the fact that a sphere cannot be projected onto a plane without stretching or tearing.</p>
 
@@ -271,4 +271,4 @@
 
   <script src="js/main.js"></script>
 </body>
-</html>
+</html>