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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", sans-serif;
  background: #f5f5f7;
  color: #1d1d1f;
  margin: 0;
  padding: 20px;
  line-height: 1.7;
}

.container {
  max-width: 680px;
  margin: 0 auto;
  background: #fff;
  border-radius: 16px;
  padding: 32px 28px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

nav { margin-bottom: 24px; }
nav a { color: #007aff; text-decoration: none; font-size: 0.95em; }

h1 { font-size: 1.7em; margin-top: 0; }
h2 { font-size: 1.1em; margin-top: 2em; border-bottom: 1px solid #eee; padding-bottom: 6px; }

a { color: #007aff; }

/* サポートトップのカードリンク */
.links { display: flex; flex-direction: column; gap: 12px; margin-top: 24px; }
.card {
  display: block;
  padding: 16px 20px;
  background: #f5f5f7;
  border-radius: 12px;
  text-decoration: none;
  color: #1d1d1f;
  font-weight: 500;
  transition: background 0.15s;
}
.card:hover { background: #e8e8ed; }

/* FAQ のアコーディオン */
details {
  border: 1px solid #eee;
  border-radius: 10px;
  padding: 12px 16px;
  margin-bottom: 10px;
}
details[open] { background: #f9f9fb; }
summary {
  font-weight: 500;
  cursor: pointer;
  list-style: none;
  padding-right: 8px;
}
summary::-webkit-details-marker { display: none; }
summary::after { content: " ＋"; color: #999; float: right; }
details[open] summary::after { content: " −"; }
details p { margin: 10px 0 0; color: #444; }

footer {
  margin-top: 40px;
  color: #999;
  font-size: 0.85em;
  text-align: center;
}