body {
  background: #f7f9fa;
}

.navbar-brand img {
  height: 42px;
  width: auto;
}

.ntk-logo {
  max-height: 32px;
  width: auto;
}

.subject-links a {
  align-items: center;
  border: 1px solid #ced4da;
  border-radius: .35rem;
  color: #0b5e7f;
  display: inline-flex;
  font-weight: 600;
  height: 38px;
  padding: 0 .65rem;
  text-decoration: none;
}

.tree-panel,
.subject-card {
  background: #fff;
  border: 1px solid #d9e0e4;
  border-radius: .5rem;
  box-shadow: 0 1px 2px rgb(0 0 0 / 4%);
  padding: 1rem;
}

.tree-scroll {
  max-height: calc(100vh - 13rem);
  overflow: auto;
}

.psh-tree,
.psh-tree ul {
  list-style: none;
  margin: 0;
  padding-left: 1rem;
}

.psh-tree {
  padding-left: 0;
}

.psh-tree details {
  margin: .1rem 0;
}

.psh-tree summary {
  border-radius: .25rem;
  cursor: pointer;
  padding: .15rem .25rem;
}

.psh-tree a {
  border-radius: .25rem;
  color: #25323a;
  display: inline-block;
  padding: .15rem .25rem;
  text-decoration: none;
}

.psh-tree a:hover,
.psh-tree summary:hover,
.psh-tree .active {
  background: #e7f2f7;
  color: #005f82;
}

.subject-title {
  border-bottom: 1px solid #e4eaed;
  margin-bottom: 1rem;
  padding-bottom: 1rem;
}

.subject-title h1 {
  font-size: 2rem;
  font-weight: 700;
  margin: 0;
}

.subject-title .shortcut {
  color: #65737c;
  font-size: 1rem;
  margin-left: .5rem;
}

.subject-title .subtitle {
  color: #4b5b64;
  font-size: 1.15rem;
}

.subject-list {
  list-style: none;
  padding-left: 0;
}

.subject-list li {
  line-height: 1.65;
}

.footer {
  color: #4d565c;
  padding-bottom: 2rem;
}