* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Segoe UI', 'Helvetica Neue', sans-serif;
  background-color: #f5fafd;
  color: #333;
  line-height: 1.6;
}

header {
  background-color: #90caf9;
  color: white;
  padding: 1rem;
  text-align: center;
}

header a {
  color: white;
  text-decoration: none;
  margin: 0 1rem;
}

header a img {
  height: 40px;
  vertical-align: middle;
}

nav ul {
  list-style: none;
  padding: 0;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  margin: 1rem 0 0 0;
}

nav ul li {
  margin: 0 10px;
}

nav ul li a {
  background-color: white;
  color: #2196f3;
  padding: 6px 12px;
  border-radius: 20px;
  text-decoration: none;
  transition: background-color 0.2s ease;
  border: 1px solid #90caf9;
}

nav ul li a:hover {
  background-color: #e3f2fd;
}

main {
  padding: 2rem 1rem;
  max-width: 800px;
  margin: auto;
}

h2 {
  border-bottom: 2px solid #90caf9;
  padding-bottom: 0.3rem;
  margin-top: 2rem;
}

h3 {
  margin-top: 1.5rem;
}

main div {
  margin: 0.5rem 0;
}

main a {
  color: #1565c0;
  text-decoration: none;
  padding: 6px 10px;
  border-radius: 6px;
  display: inline-block;
  background-color: #e3f2fd;
  transition: background-color 0.2s ease;
}

main a:hover {
  background-color: #bbdefb;
}

.app-desc {
  margin: 0px;
  padding: 0px;
}

.back-top {
  text-align: right;
}

details.game-card > summary {
  list-style: none;
  cursor: pointer;
  font-weight: 600;
  outline: none;
  font-size: 1.2em;
}

details.game-card > summary::before {
  content: "▼";
  display: inline-block;
  transform: rotate(-90deg);
  transition: transform .2s ease;
  margin-right: .4em;
  font-size: .9em;
  opacity: .8;
}

footer {
  text-align: center;
  padding: 1rem;
  background-color: #e1f5fe;
  font-size: 0.9rem;
  margin-top: 2rem;
}

footer a {
  color: #039be5;
  text-decoration: none;
}

@media (max-width: 600px) {
  nav ul {
    flex-direction: column;
    align-items: center;
  }

  header a img {
    height: 30px;
  }
}