* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  font-family: 'Meiryo UI', sans-serif;
  background: #fff;
  color: #222;
  -webkit-user-select: none;
}

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  position: sticky;
  top: 0;
  background: #f8f9fa;
  padding: 1rem 2rem;
  font-size: 1.5rem;
  font-weight: bold;
  box-shadow: 0 2px 5px #0008;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header nav a {
  color: #1f2951;
  text-decoration: none;
  margin-left: 1rem;
}

header nav a:hover {
  color: #f7931e;
}

main {
  display: flex;
  flex: 1;
  overflow: hidden;
}

.toc-wrapper {
  width: 220px;
  background: #f3f4f6;
  padding: 1rem 1.5rem;
  overflow-y: auto;
  font-size: 0.9rem;
  line-height: 1.4;
}

.toc-wrapper h2 {
  color: #f7931e;
  font-size: 1.2rem;
  margin-bottom: 0.8rem;
}

.toc-wrapper ul {
  list-style: none;
}

.toc-wrapper li {
  margin-bottom: 0.5rem;
}

.toc-wrapper a {
  color: #1f2951;
  text-decoration: none;
}

.toc-wrapper a:hover {
  text-decoration: underline;
  color: #ffb933;
}

.toc-toggle {
  display: none;
  background: #f3f4f6;
  padding: 1rem;
  font-weight: bold;
  cursor: pointer;
}

article.article {
  flex: 1;
  padding: 2rem 3rem;
  overflow-y: auto;
  font-size: 1.1rem;
  line-height: 1.7;
}

article.article h1 {
  font-size: 2.2rem;
  color: #f7931e;
}

article.article h2 {
  font-size: 1.6rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
  border-bottom: 2px solid #bbb;
  color: #008080;
}

article.article p {
  margin-bottom: 1.2rem;
}

aside.sidebar {
  width: 180px;
  background: #f3f4f6;
  padding: 1rem 1.5rem;
  border-left: 1px solid #ddd;
  font-size: 0.9rem;
}

aside.sidebar h3 {
  color: #f7931e;
  font-size: 1.2rem;
  margin-bottom: 1rem;
}

aside.sidebar a {
  text-decoration: none;
  color: #1f2951;
}

aside.sidebar a:hover {
  color: #f7931e;
}

canvas {
  display: block;
  margin: 1rem auto;
  border: 1px solid black;
}

.dropdown-toggle {
  padding: 10px 20px;
  font-size: 16px;
  font-weight: bold;
  color: #fff;
  background-color: #007ACC;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s ease, box-shadow 0.2s ease;
  margin-top: 1rem;
}

.dropdown-toggle:hover {
  background-color: #005f99;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.dropdown-toggle:active {
  background-color: #004f80;
  transform: translateY(1px);
}

.dropdown-content {
  display: none;
  border: 1px solid black;
  padding: 1rem;
  margin-top: 0.5rem;
}

@media (max-width: 768px) {
  main {
    flex-direction: column;
  }
  .toc-wrapper {
    width: 100%;
    display: none;
  }
  .toc-wrapper.active {
    display: block;
  }
  .toc-toggle {
    display: block;
  }
  aside.sidebar {
    width: 100%;
    border-left: none;
    border-top: 1px solid #ddd;
  }
}

.dashed-hr {
  border: none;
  border-top: dashed 2px black;
  margin: 30px 0px;
  height: 1px;
}

.block {
  margin: 5px 10px 5px 15px;
  border:1px solid black;
  border-radius: 5px;
  padding: 5px;
}