diff --git a/01-basics.html b/01-basics.html
index e67deddb31..dd1c5c7662 100644
--- a/01-basics.html
+++ b/01-basics.html
@@ -485,7 +485,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <ul><li><p>以前書いた数百行の回復は、古いバージョンの論文のコピーを作成した場合にのみ可能です。
 前に書いた文章を失う危険性は、このページの上にある漫画に描かれているような問題のあるワークフローになることが多いです。</p></li>
diff --git a/05-history.html b/05-history.html
index dfc7f60cbd..4fc32bc744 100644
--- a/05-history.html
+++ b/05-history.html
@@ -754,7 +754,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>答えは (5) - 2 と 4 の両方です。</p>
 <p>The <code>checkout</code> command restores files from the repository,
@@ -811,7 +811,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The command <code>git log</code> lists project history with commit
 IDs.</p>
@@ -869,7 +869,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>答えは2です。</p>
 <p>The command <code>git add venus.txt</code> places the current version
@@ -934,7 +934,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>After adding a change, <code>git checkout</code> can not be used
 directly. Let’s look at the output of <code>git status</code>:</p>
diff --git a/06-ignore.html b/06-ignore.html
index 65f80128c1..eb22532d8e 100644
--- a/06-ignore.html
+++ b/06-ignore.html
@@ -563,7 +563,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p><code>results/plots</code>
 内のファイルのみを無視するのであれば、<code>.gitignore</code> に
@@ -603,7 +603,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>以下二文を .gitignore に加えましょう：</p>
 <div class="codewrapper">
@@ -651,7 +651,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p><code>results/</code> のコンテンツは無視したいが、
 <code>results/data/</code> のコンテンツは無視したくない場合、
@@ -700,7 +700,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>results/data/position/gps/*.data</code> を使えば
 <code>results/data/position/gps</code> 内にある全ての <code>.data</code>
@@ -739,7 +739,7 @@ <h4 class="accordion-header" id="headingSolution5">
   解答
   </h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>In the <code>.gitignore</code> file, write:</p>
 <div class="codewrapper">
@@ -779,7 +779,7 @@ <h4 class="accordion-header" id="headingSolution6">
   解答
   </h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>感嘆符 <code>!</code>
 は無視してあったファイルを対象から除外する効果があります。
@@ -821,7 +821,7 @@ <h4 class="accordion-header" id="headingSolution7">
   解答
   </h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><p><code>log_*</code> もしくは <code>log*</code> を .gitignore
 に加えます。</p></li>
diff --git a/09-conflict.html b/09-conflict.html
index 96d4667290..cf2ab1a5f7 100644
--- a/09-conflict.html
+++ b/09-conflict.html
@@ -750,7 +750,7 @@ <h3 class="callout-title">Conflicts on Non-textual files</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1"> Show me the solution </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>Let’s try it. Suppose Dracula takes a picture of Martian surface and
 calls it <code>mars.jpg</code>.</p>
@@ -967,7 +967,7 @@ <h3 class="callout-title">A Typical Work Session</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2"> Show me the solution </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <table class="table"><colgroup><col width="1%"><col width="24%"><col width="74%"></colgroup><thead><tr class="header"><th>order</th>
 <th>action . . . . . .</th>
diff --git a/14-supplemental-rstudio.html b/14-supplemental-rstudio.html
index 96ed080577..303d9d94a2 100644
--- a/14-supplemental-rstudio.html
+++ b/14-supplemental-rstudio.html
@@ -548,7 +548,7 @@ <h4 class="accordion-header" id="headingSolution1">
   Solution to Challenge
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>This can be done in Rstudio:</p>
 <div class="codewrapper sourceCode" id="cb1">
diff --git a/aio.html b/aio.html
index 86e34542c8..f665a59a08 100644
--- a/aio.html
+++ b/aio.html
@@ -561,7 +561,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <ul>
 <li><p>以前書いた数百行の回復は、古いバージョンの論文のコピーを作成した場合にのみ可能です。
@@ -2443,7 +2443,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>答えは (5) - 2 と 4 の両方です。</p>
 <p>The <code>checkout</code> command restores files from the repository,
@@ -2502,7 +2502,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The command <code>git log</code> lists project history with commit
 IDs.</p>
@@ -2564,7 +2564,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>答えは2です。</p>
 <p>The command <code>git add venus.txt</code> places the current version
@@ -2629,7 +2629,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>After adding a change, <code>git checkout</code> can not be used
 directly. Let’s look at the output of <code>git status</code>:</p>
@@ -2939,7 +2939,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p><code>results/plots</code>
 内のファイルのみを無視するのであれば、<code>.gitignore</code> に
@@ -2979,7 +2979,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>以下二文を .gitignore に加えましょう：</p>
 <div class="codewrapper">
@@ -3027,7 +3027,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p><code>results/</code> のコンテンツは無視したいが、
 <code>results/data/</code> のコンテンツは無視したくない場合、
@@ -3076,7 +3076,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>results/data/position/gps/*.data</code> を使えば
 <code>results/data/position/gps</code> 内にある全ての <code>.data</code>
@@ -3115,7 +3115,7 @@ <h4 class="accordion-header" id="headingSolution5">
   解答
   </h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>In the <code>.gitignore</code> file, write:</p>
 <div class="codewrapper">
@@ -3155,7 +3155,7 @@ <h4 class="accordion-header" id="headingSolution6">
   解答
   </h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>感嘆符 <code>!</code>
 は無視してあったファイルを対象から除外する効果があります。
@@ -3199,7 +3199,7 @@ <h4 class="accordion-header" id="headingSolution7">
   解答
   </h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><p><code>log_*</code> もしくは <code>log*</code> を .gitignore
@@ -4582,7 +4582,7 @@ <h3 class="callout-title">Conflicts on Non-textual files</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1"> Show me the solution </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>Let’s try it. Suppose Dracula takes a picture of Martian surface and
 calls it <code>mars.jpg</code>.</p>
@@ -4824,7 +4824,7 @@ <h3 class="callout-title">A Typical Work Session</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2"> Show me the solution </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <table class="table">
 <colgroup>
@@ -5573,7 +5573,7 @@ <h4 class="accordion-header" id="headingSolution1">
   Solution to Challenge
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>This can be done in Rstudio:</p>
 <div class="codewrapper sourceCode" id="cb1">
diff --git a/discuss.html b/discuss.html
index ddec564fe5..ef24548b45 100644
--- a/discuss.html
+++ b/discuss.html
@@ -849,7 +849,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1"> Show me the solution </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>To do this, your .gitignore would look like this:</p>
 <div class="codewrapper">
diff --git a/instructor/01-basics.html b/instructor/01-basics.html
index 80fe49333b..b2f019eba2 100644
--- a/instructor/01-basics.html
+++ b/instructor/01-basics.html
@@ -487,7 +487,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <ul><li><p>以前書いた数百行の回復は、古いバージョンの論文のコピーを作成した場合にのみ可能です。
 前に書いた文章を失う危険性は、このページの上にある漫画に描かれているような問題のあるワークフローになることが多いです。</p></li>
diff --git a/instructor/05-history.html b/instructor/05-history.html
index 2f0dfdfeea..5a08a3eecd 100644
--- a/instructor/05-history.html
+++ b/instructor/05-history.html
@@ -756,7 +756,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>答えは (5) - 2 と 4 の両方です。</p>
 <p>The <code>checkout</code> command restores files from the repository,
@@ -813,7 +813,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The command <code>git log</code> lists project history with commit
 IDs.</p>
@@ -871,7 +871,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>答えは2です。</p>
 <p>The command <code>git add venus.txt</code> places the current version
@@ -936,7 +936,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>After adding a change, <code>git checkout</code> can not be used
 directly. Let’s look at the output of <code>git status</code>:</p>
diff --git a/instructor/06-ignore.html b/instructor/06-ignore.html
index 389397d19a..810ace73a3 100644
--- a/instructor/06-ignore.html
+++ b/instructor/06-ignore.html
@@ -565,7 +565,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p><code>results/plots</code>
 内のファイルのみを無視するのであれば、<code>.gitignore</code> に
@@ -605,7 +605,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>以下二文を .gitignore に加えましょう：</p>
 <div class="codewrapper">
@@ -653,7 +653,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p><code>results/</code> のコンテンツは無視したいが、
 <code>results/data/</code> のコンテンツは無視したくない場合、
@@ -702,7 +702,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>results/data/position/gps/*.data</code> を使えば
 <code>results/data/position/gps</code> 内にある全ての <code>.data</code>
@@ -741,7 +741,7 @@ <h4 class="accordion-header" id="headingSolution5">
   解答
   </h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>In the <code>.gitignore</code> file, write:</p>
 <div class="codewrapper">
@@ -781,7 +781,7 @@ <h4 class="accordion-header" id="headingSolution6">
   解答
   </h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>感嘆符 <code>!</code>
 は無視してあったファイルを対象から除外する効果があります。
@@ -823,7 +823,7 @@ <h4 class="accordion-header" id="headingSolution7">
   解答
   </h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><p><code>log_*</code> もしくは <code>log*</code> を .gitignore
 に加えます。</p></li>
diff --git a/instructor/09-conflict.html b/instructor/09-conflict.html
index 76db47ccb3..a4c86f61ea 100644
--- a/instructor/09-conflict.html
+++ b/instructor/09-conflict.html
@@ -752,7 +752,7 @@ <h3 class="callout-title">Conflicts on Non-textual files</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1"> Show me the solution </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>Let’s try it. Suppose Dracula takes a picture of Martian surface and
 calls it <code>mars.jpg</code>.</p>
@@ -969,7 +969,7 @@ <h3 class="callout-title">A Typical Work Session</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2"> Show me the solution </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <table class="table"><colgroup><col width="1%"><col width="24%"><col width="74%"></colgroup><thead><tr class="header"><th>order</th>
 <th>action . . . . . .</th>
diff --git a/instructor/14-supplemental-rstudio.html b/instructor/14-supplemental-rstudio.html
index f381d66652..8d1ea01125 100644
--- a/instructor/14-supplemental-rstudio.html
+++ b/instructor/14-supplemental-rstudio.html
@@ -550,7 +550,7 @@ <h4 class="accordion-header" id="headingSolution1">
   Solution to Challenge
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>This can be done in Rstudio:</p>
 <div class="codewrapper sourceCode" id="cb1">
diff --git a/instructor/aio.html b/instructor/aio.html
index 5e81347777..37f2802bdc 100644
--- a/instructor/aio.html
+++ b/instructor/aio.html
@@ -564,7 +564,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <ul>
 <li><p>以前書いた数百行の回復は、古いバージョンの論文のコピーを作成した場合にのみ可能です。
@@ -2450,7 +2450,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>答えは (5) - 2 と 4 の両方です。</p>
 <p>The <code>checkout</code> command restores files from the repository,
@@ -2509,7 +2509,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The command <code>git log</code> lists project history with commit
 IDs.</p>
@@ -2571,7 +2571,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>答えは2です。</p>
 <p>The command <code>git add venus.txt</code> places the current version
@@ -2636,7 +2636,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>After adding a change, <code>git checkout</code> can not be used
 directly. Let’s look at the output of <code>git status</code>:</p>
@@ -2947,7 +2947,7 @@ <h4 class="accordion-header" id="headingSolution1">
   解答
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p><code>results/plots</code>
 内のファイルのみを無視するのであれば、<code>.gitignore</code> に
@@ -2987,7 +2987,7 @@ <h4 class="accordion-header" id="headingSolution2">
   解答
   </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>以下二文を .gitignore に加えましょう：</p>
 <div class="codewrapper">
@@ -3035,7 +3035,7 @@ <h4 class="accordion-header" id="headingSolution3">
   解答
   </h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p><code>results/</code> のコンテンツは無視したいが、
 <code>results/data/</code> のコンテンツは無視したくない場合、
@@ -3084,7 +3084,7 @@ <h4 class="accordion-header" id="headingSolution4">
   解答
   </h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>results/data/position/gps/*.data</code> を使えば
 <code>results/data/position/gps</code> 内にある全ての <code>.data</code>
@@ -3123,7 +3123,7 @@ <h4 class="accordion-header" id="headingSolution5">
   解答
   </h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>In the <code>.gitignore</code> file, write:</p>
 <div class="codewrapper">
@@ -3163,7 +3163,7 @@ <h4 class="accordion-header" id="headingSolution6">
   解答
   </h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>感嘆符 <code>!</code>
 は無視してあったファイルを対象から除外する効果があります。
@@ -3207,7 +3207,7 @@ <h4 class="accordion-header" id="headingSolution7">
   解答
   </h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><p><code>log_*</code> もしくは <code>log*</code> を .gitignore
@@ -4593,7 +4593,7 @@ <h3 class="callout-title">Conflicts on Non-textual files</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1"> Show me the solution </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>Let’s try it. Suppose Dracula takes a picture of Martian surface and
 calls it <code>mars.jpg</code>.</p>
@@ -4835,7 +4835,7 @@ <h3 class="callout-title">A Typical Work Session</h3>
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2"> Show me the solution </h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <table class="table">
 <colgroup>
@@ -5589,7 +5589,7 @@ <h4 class="accordion-header" id="headingSolution1">
   Solution to Challenge
   </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>This can be done in Rstudio:</p>
 <div class="codewrapper sourceCode" id="cb1">
diff --git a/instructor/discuss.html b/instructor/discuss.html
index 370f36494d..421b6fc549 100644
--- a/instructor/discuss.html
+++ b/instructor/discuss.html
@@ -851,7 +851,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1"> Show me the solution </h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>To do this, your .gitignore would look like this:</p>
 <div class="codewrapper">
diff --git a/pkgdown.yml b/pkgdown.yml
index 781d96c80a..df66f6dce2 100644
--- a/pkgdown.yml
+++ b/pkgdown.yml
@@ -2,4 +2,4 @@ pandoc: 3.1.11
 pkgdown: 2.1.0
 pkgdown_sha: ~
 articles: {}
-last_built: 2024-08-13T01:13Z
+last_built: 2024-08-13T04:52Z