:root {
  --paper: #f6f4ef;
  --card: #ffffff;
  --ink: #1f2430;
  --ink2: #5b6170;
  --line: #e2ded4;
  --navy: #233a8b;
  --orange: #f07a1a;
  color-scheme: light;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic", Meiryo, system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.85;
  letter-spacing: .02em;
}

a { color: var(--navy); }

.top {
  max-width: 720px;
  margin: 0 auto;
  padding: 20px 20px 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
  font-size: 17px;
}

.brand img { border-radius: 9px; }

nav { display: flex; gap: 18px; font-size: 14px; }

nav a { color: var(--ink2); text-decoration: none; padding: 4px 0; }

nav a[aria-current="page"] {
  color: var(--ink);
  font-weight: 700;
  box-shadow: inset 0 -2px 0 var(--orange);
}

main {
  max-width: 720px;
  margin: 28px auto 0;
  padding: 0 20px;
}

section, .doc {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 28px 32px;
  margin-bottom: 20px;
}

.hero { display: flex; align-items: center; gap: 24px; }

.hero img { border-radius: 22px; flex: none; }

.hero h1 { margin: 0 0 4px; font-size: 26px; letter-spacing: .04em; }

.hero p { margin: 0; color: var(--ink2); }

.hero p span { display: inline-block; }

h1, h2, summary { word-break: auto-phrase; }

h1 { font-size: 24px; line-height: 1.5; margin: 0 0 8px; }

h2 {
  font-size: 18px;
  line-height: 1.5;
  margin: 0 0 12px;
  padding-left: 12px;
  border-left: 4px solid var(--orange);
}

.doc h2 { margin-top: 36px; }

.doc h1 + p { color: var(--ink2); font-size: 14px; }

p { margin: 0 0 12px; }

ul, ol { margin: 0 0 12px; padding-left: 1.4em; }

li + li { margin-top: 4px; }

.mail { font-size: 18px; font-weight: 700; }

.note { color: var(--ink2); font-size: 14px; margin-bottom: 0; }

details { border-top: 1px solid var(--line); }

details:last-of-type { border-bottom: 1px solid var(--line); }

summary {
  cursor: pointer;
  list-style: none;
  padding: 14px 28px 14px 0;
  font-weight: 700;
  position: relative;
}

summary::-webkit-details-marker { display: none; }

summary::after {
  content: "+";
  position: absolute;
  right: 4px;
  top: 12px;
  color: var(--orange);
  font-size: 20px;
  font-weight: 400;
}

details[open] summary::after { content: "−"; }

details p { color: var(--ink2); padding-bottom: 6px; }

footer {
  max-width: 720px;
  margin: 12px auto 40px;
  padding: 0 20px;
  color: var(--ink2);
  font-size: 13px;
}

@media (max-width: 560px) {
  .top { padding: 16px 16px 0; }
  main { padding: 0 16px; margin-top: 20px; }
  footer { padding: 0 16px; }
  section, .doc { padding: 22px 20px; }
  .hero { flex-direction: column; align-items: flex-start; gap: 16px; }
  .hero img { width: 72px; height: 72px; border-radius: 17px; }
  nav { gap: 14px; font-size: 13px; }
}