body {
  font-family: Arial, sans-serif;
  background: #f5f7fa;
  margin: 0;
  padding: 0 0 32px 0;
  color: #222;
}
header {
  background: #2957a4;
  color: #fff;
  padding: 32px 16px 18px 16px;
  text-align: center;
}
main {
  max-width: 800px;
  margin: 32px auto;
  background: #fff;
  padding: 32px 24px;
  border-radius: 16px;
  box-shadow: 0 2px 12px #0001;
}
h1, h2 {
  font-weight: 900;
}
h2 {
  color: #2957a4;
  margin-top: 32px;
  border-bottom: 1px solid #e1e5f2;
  padding-bottom: 4px;
}
details {
  margin-bottom: 24px;
}
.exemplo-btn {
  background: #2957a4;
  color: #fff;
  border: none;
  border-radius: 5px;
  padding: 6px 18px;
  margin: 10px 0;
  cursor: pointer;
  font-size: 1em;
  transition: background 0.2s;
}
.exemplo-btn:hover {
  background: #13335d;
}
.resposta {
  display: none;
  background: #f1f4fa;
  border-left: 4px solid #2957a4;
  padding: 16px;
  margin-top: 10px;
  border-radius: 5px;
  overflow-x: auto;
}
code, pre {
  background: none;
  font-family: "Fira Mono", "Consolas", monospace;
  color: #13243b;
}
pre {
  margin: 0;
  font-size: 1em;
}
@media (max-width: 650px) {
  main { padding: 16px 4px; }
  h1 { font-size: 1.5em; }
}