*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue",
    "Yu Gothic", "YuGothic", "Meiryo", sans-serif;
  color: #222222;
  line-height: 1.7;
  background-color: #f5f7fb;
}

/* layout */
.container {
  width: 90%;
  max-width: 1160px;
  margin: 0 auto;
}

.section {
  padding: 80px 0;
}

.section-bg {
  background-color: #ffffff;
}

.section-title {
  font-size: 1.8rem;
  letter-spacing: 0.08em;
  text-align: center;
  margin-bottom: 40px;
  position: relative;
  display: block;
}

.section-title span {
  display: block;
  font-size: 0.9rem;
  color: #00a4d8;
  margin-top: 6px;
}

.section-lead {
  text-align: center;
  margin-bottom: 40px;
  color: #555555;
}

/* header */
.site-header {
  position: sticky;
  top: 0;
  z