body {
  margin: 0;
  font-family: 'Noto Sans JP', sans-serif;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

.layout {
  display: flex;
  height: 100vh;
}

.sidebar {
  width: 100px;
  background-color: #333;
  color: white;
  padding: 1rem;
  overflow-y: auto;
}

.sidebar h2 {
  font-size: 1.1em;
  margin-top: 0;
  color:yellow;
}

.sidebar ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sidebar li {
  margin: 0.5em 0;
}

.sidebar li :hover{
  color: rgb(233, 187, 166);
}

.sidebar a {
  color: white;
  text-decoration: none;
}

.content-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.site-header {
  background-color: #2e5f96;
  color: white;
  padding: 0.3rem 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-shrink: 0;
}

main {
  flex: 1;
  overflow-y: auto;
  padding: 0.3rem 1rem;
  background-color: rgb(238, 238, 238);
}

/* 本棚のデザイン（同じでOK） */
.shelf {
  margin-bottom: 3em;
}

.shelf h2 {
  font-size: 1.2em;
  border-left: 6px solid #444;
  padding-left: 0.5em;
  margin-bottom: 1em;
}

.books {
  display: flex;
  gap: 0.5em;
  flex-wrap: wrap;
}

.book {
  writing-mode: vertical-rl;
  text-align: center;
  width: 2.5em;
  height: 150px;
  background: #d8cfc4;
  color: #222;
  border: 1px solid #999;
  box-shadow: 2px 2px 5px rgba(0,0,0,0.2);
  padding: 0.3em;
  font-size: 0.9em;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s ease;
  text-decoration: none;
}

.book:hover {
  transform: scale(1.05);
  background: #c6b8a8;
}

.navi{
  color:white;
  text-decoration:none;
  margin-right:1rem;
}
p{
  line-height: 150%;
}