* {
  box-sizing: border-box;
}
body {
  margin: 0;
  color: #233747;
  background: #f7f9fc;
  font-family:
    -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN",
    "Noto Sans JP", sans-serif;
  line-height: 1.9;
}
header,
main,
footer {
  max-width: 840px;
  margin: auto;
  padding: 24px;
}
header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 1px solid #d8e1eb;
}
header > a {
  font-weight: 700;
}
header span,
nav,
footer {
  font-size: 14px;
}
main {
  padding-top: 40px;
}
h1 {
  font-size: clamp(26px, 5vw, 38px);
  line-height: 1.5;
  letter-spacing: -0.025em;
}
h2 {
  font-size: 22px;
  line-height: 1.6;
}
section {
  margin-top: 40px;
}
a {
  color: #245c91;
  text-underline-offset: 4px;
  overflow-wrap: anywhere;
}
a:focus-visible {
  outline: 3px solid #245c91;
  outline-offset: 5px;
}
.lead {
  font-size: 18px;
}
.start {
  display: inline-block;
  padding: 10px 20px;
  background: #245c91;
  color: white;
  border-radius: 8px;
  text-decoration: none;
}
footer {
  border-top: 1px solid #d8e1eb;
  margin-top: 40px;
  padding-bottom: 48px;
}
footer nav a {
  display: inline-block;
  margin: 6px 0;
}
@media (max-width: 480px) {
  header {
    flex-direction: column;
    gap: 0;
  }
  header,
  main,
  footer {
    padding-left: 20px;
    padding-right: 20px;
  }
}