body {
  margin: 0;
  font-family: Arial, sans-serif;
}

.navbar {
  background-color: #1b1b1b;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 75px;
  width: 100%;
  position: fixed;
  top: 0;
  left: 0;
}

.nav-left {
  list-style: none;
  display: flex;
  margin: 0;
  padding: 0;
}

.nav-left li {
  position: relative;
}

.nav-left li a {
  display: flex;
  align-items: center;
  padding: 0 15px;
  text-decoration: none;
  color: white;
  height: 75px;
  font-size: 20px;
  white-space: nowrap;
}

.active-page {
    background-color: #d63b3b;
}

.nav-left li:hover>a {
  background-color: #d63b3b;
}

.nav-left li .dropdown-menu {
  display: none;
  position: absolute;
  top: 75px;
  left: 0;
  background: #f4f4f4;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  min-width: 308px;
  z-index: 1000;
}

.nav-left li .dropdown-menu li a {
  color: #333;
  padding: 5px 10px;
  display: block;
  font-size: 28px;
}

.nav-left li .dropdown-menu li a:hover {
  background-color: #ddd;
}

.nav-left li.dropdown:hover .dropdown-menu {
  display: block;
}

.main-content {
  padding: 100px 40px;
}

.h1-topic {
  margin-top: 60px;
  text-align: center;
  font-size: 50px;
  color: #333;
}

.info {
  margin: 20px auto;
  margin-left: 30px;
  padding: 20px;
  font-size: 34px;
}

.info li {
  margin-bottom: 30px;
}

.list {
  margin-left: 30px;
  margin-top: 80px;
  padding: 40px;
  font-size: 34px;
}

.list li {
  margin-bottom: 30px;
}

.info-topic {
  margin: 20px auto;
  margin-left: 30px;
  padding: 20px;
  font-size: 30px;
}