html,
body {
  display: flex;
  flex-direction: column;
}

header,
footer {
  font-size: 1.5em;
  display: flex;
  align-items: center;
}

header {
  justify-content: space-between;
}
footer {
  justify-content: flex-end;
}

.main {
  flex: 1;
  display: flex;
}

.header-links a,
.footer-links a {
  margin-left: 25px;
}

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

.content {
  display: flex;
  justify-content: space-between;
  width: 100%;
}

.posts,
.topics {
  padding: 0 40px;
  align-self: center;
}

.topics {
  font-size: 3em;
}

.posts {
  font-size: 2em;
  text-align: right;
  flex: 1;
}

.post {
  font-style: italic;
  margin-bottom: 25px;
}

.topic a {
  position: relative;
  display: inline-block;
  color: inherit;
  text-decoration: none;
  margin-bottom: 25px;
  transition: color 0.5s ease;
}

.topic a::after {
  content: "";
  height: 2px;
  display: block;
  margin-top: 4px;
  background: currentColor;
  width: 0;
  right: 100%;
  position: absolute;
  transition:
    width 0.5s ease,
    right 0.5s ease;
}

.topic a:hover::after,
.topic a.active::after {
  width: 100%;
  right: 0;
}