body {
  margin: 0;
  font-family: Arial, sans-serif;
  background-color: #121212;
  color: #f0f0f0;
}
header, footer {
  background-color: #1e1e1e;
  padding: 1em;
  text-align: center;
}
main {
  padding: 1em;
}
a {
  color: #90caf9;
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}
.category-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1em;
}
.category-list a {
  display: block;
  padding: 1em;
  background-color: #2c2c2c;
  border-radius: 8px;
  text-align: center;
}
.file-list {
  list-style: none;
  padding: 0;
}
.file-list li {
  margin: 0.5em 0;
}
.upload-form {
  margin-top: 2em;
}