diff --git a/01 - Welcome.ipynb b/01 - Welcome.ipynb
index 0adb27f6d88837561f1a724dd4c4f64383c44298..80542ed8d2d7aefddb9ce67cc736847651427646 100644
--- a/01 - Welcome.ipynb	
+++ b/01 - Welcome.ipynb	
@@ -2,7 +2,7 @@
  "metadata": {
   "celltoolbar": "Slideshow",
   "name": "",
-  "signature": "sha256:6c570ac428c0fbfa0115d6c05d52e3c05410cd3de42ae35e7ee7feb0f435a641"
+  "signature": "sha256:a016c0815699df8dae5155425df47f34e59e2aac64d4fa7f4edaa9c43a33ad3f"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -259,8 +259,8 @@
       {
        "html": [
         "<style>/* Remove the vertical scrollbar added by nbconvert. */\n",
-        "html {\n",
-        "  overflow-y: hidden;\n",
+        ".reveal {\n",
+        "  overflow: hidden;\n",
         "}\n",
         "\n",
         "/* Workaround some highlight.js bugs in language autodetection. */\n",
@@ -287,7 +287,7 @@
        "output_type": "pyout",
        "prompt_number": 1,
        "text": [
-        "<IPython.core.display.HTML at 0x33caa50>"
+        "<IPython.core.display.HTML at 0x1f71a50>"
        ]
       }
      ],
diff --git a/02 - Introduction to Python (1).ipynb b/02 - Introduction to Python (1).ipynb
index 2e37bf916ba9bcb9889b30ac88fc076785c6e3e4..fdc809c37ffd5a2409c0a724772151d878652595 100644
--- a/02 - Introduction to Python (1).ipynb	
+++ b/02 - Introduction to Python (1).ipynb	
@@ -2,7 +2,7 @@
  "metadata": {
   "celltoolbar": "Slideshow",
   "name": "",
-  "signature": "sha256:06632e3aab84ba95070db9bd6588d5a6fa8e7440ebe85cac2ce1a3c91911db47"
+  "signature": "sha256:48b5e4d61de5dfa8cebfe8fe0c78f8587586ee15c8ea50fe5c1d67f8ea5caa4a"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -893,8 +893,8 @@
       {
        "html": [
         "<style>/* Remove the vertical scrollbar added by nbconvert. */\n",
-        "html {\n",
-        "  overflow-y: hidden;\n",
+        ".reveal {\n",
+        "  overflow: hidden;\n",
         "}\n",
         "\n",
         "/* Workaround some highlight.js bugs in language autodetection. */\n",
@@ -919,13 +919,13 @@
        ],
        "metadata": {},
        "output_type": "pyout",
-       "prompt_number": 25,
+       "prompt_number": 1,
        "text": [
-        "<IPython.core.display.HTML at 0x7f39d4043c90>"
+        "<IPython.core.display.HTML at 0x3463a50>"
        ]
       }
      ],
-     "prompt_number": 25
+     "prompt_number": 1
     }
    ],
    "metadata": {}
diff --git a/02 - Introduction to Python (2).ipynb b/02 - Introduction to Python (2).ipynb
index ff39ed75c0ddd9fee4d78864eb313a5965a61f31..d7010ad5a4bc1c27708e86ce779188c6d3977840 100644
--- a/02 - Introduction to Python (2).ipynb	
+++ b/02 - Introduction to Python (2).ipynb	
@@ -2,7 +2,7 @@
  "metadata": {
   "celltoolbar": "Slideshow",
   "name": "",
-  "signature": "sha256:57d29de0d77287096e49247676a76ea06e3730e1e5f819ecfc6b4b3f6d85e4e9"
+  "signature": "sha256:7b4c4307ccc127e749bcc6fae78706177f4e98973022d13424e5a50a8325f24e"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -1842,8 +1842,8 @@
       {
        "html": [
         "<style>/* Remove the vertical scrollbar added by nbconvert. */\n",
-        "html {\n",
-        "  overflow-y: hidden;\n",
+        ".reveal {\n",
+        "  overflow: hidden;\n",
         "}\n",
         "\n",
         "/* Workaround some highlight.js bugs in language autodetection. */\n",
@@ -1868,13 +1868,13 @@
        ],
        "metadata": {},
        "output_type": "pyout",
-       "prompt_number": 60,
+       "prompt_number": 1,
        "text": [
-        "<IPython.core.display.HTML at 0x24f0cd0>"
+        "<IPython.core.display.HTML at 0x1873a50>"
        ]
       }
      ],
-     "prompt_number": 60
+     "prompt_number": 1
     }
    ],
    "metadata": {}
diff --git a/02 - Introduction to Python (3).ipynb b/02 - Introduction to Python (3).ipynb
index 9360d5c169dd44b0294b85c6f20168b871e12730..792c0926b7c98083cfb53aa045d31ddf4fff937a 100644
--- a/02 - Introduction to Python (3).ipynb	
+++ b/02 - Introduction to Python (3).ipynb	
@@ -2,7 +2,7 @@
  "metadata": {
   "celltoolbar": "Slideshow",
   "name": "",
-  "signature": "sha256:74676c0cad25c0954fa4f8352dda1c9010bd747de1752b4ccc667d9132427fdd"
+  "signature": "sha256:255f999074050e52200e04b7179ca89a373daf14311e382c4ab05b4444cf392e"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -851,8 +851,8 @@
       {
        "html": [
         "<style>/* Remove the vertical scrollbar added by nbconvert. */\n",
-        "html {\n",
-        "  overflow-y: hidden;\n",
+        ".reveal {\n",
+        "  overflow: hidden;\n",
         "}\n",
         "\n",
         "/* Workaround some highlight.js bugs in language autodetection. */\n",
@@ -877,13 +877,13 @@
        ],
        "metadata": {},
        "output_type": "pyout",
-       "prompt_number": 24,
+       "prompt_number": 1,
        "text": [
-        "<IPython.core.display.HTML at 0x1965a50>"
+        "<IPython.core.display.HTML at 0x2e0ea50>"
        ]
       }
      ],
-     "prompt_number": 24
+     "prompt_number": 1
     }
    ],
    "metadata": {}
diff --git a/styles/custom.css b/styles/custom.css
index 2bfc5ba144979594e9c70763a667633d278f2254..b327eff98e8985fdddc5623f8e7d04badd9ba1da 100644
--- a/styles/custom.css
+++ b/styles/custom.css
@@ -1,6 +1,6 @@
 /* Remove the vertical scrollbar added by nbconvert. */
-html {
-  overflow-y: hidden;
+.reveal {
+  overflow: hidden;
 }
 
 /* Workaround some highlight.js bugs in language autodetection. */