:root {
  --main-bg: #f7f8fa;
  --main-fg: #222;
  --accent: #4682b4;
  --card-bg: #fff;
  --border-radius: 10px;
  --shadow: 0 2px 12px rgba(60,60,60,0.07);
}
html, body {
  margin: 0;
  padding: 0;
  background: var(--main-bg);
  color: var(--main-fg);
  font-family: 'Segoe UI', 'Roboto', Arial, sans-serif;
  min-height: 100vh;
}
main {
  max-width: 650px;
  background: var(--card-bg);
  margin: 2.5rem auto;
  padding: 2.5rem 2rem 2rem 2rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  box-sizing: border-box;
}
h1 {
  color: var(--accent);
  margin-bottom: 0.7em;
  font-size: 2.2rem;
}
h2 {
  color: #333;
  margin-top: 2em;
  margin-bottom: 0.7em;
  font-size: 1.25rem;
  border-left: 4px solid var(--accent);
  padding-left: 0.6em;
}
p {
  margin-bottom: 1.2em;
  line-height: 1.7;
}
a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover {
  text-decoration: underline;
  color: #265379;
}
@media (max-width: 700px) {
  main {
    margin: 1.2rem;
    padding: 1.2rem 0.7rem;
  }
}