.container-fluid {
  background-color: #1f1e33;
  border-radius: 8px;
}

* {
  text-decoration: none;
  font-family: Arial;
  padding: 0;
  margin: 0;
  font-size: 20px;
  box-sizing: border-box;
}
#sach {
  text-align: center;
  font-size: 50px;
  font-weight: 600;
}
.thungchua {
  display: flex;
  justify-content: center;
}
.nav-link{
  color:white;
}
* {
  text-decoration: none;
  font-family: Arial;
  padding: 0;
  margin: 0;
  font-size: 20px;
  box-sizing: border-box;
}
.body {
  background-color: #f8f9fa;
}
.navbar {
  background-color: #1f1e33 !important;
}
.footer {
  background-color: #1f1e33;
  color: white;
  padding: 30px 0;
  margin-top: 30px;
}
.category-title {
  border-bottom: 2px solid #d70018;
  padding-bottom: 5px;
  margin-bottom: 20px;
  font-weight: 600;
}