:root {
  --bg: #ffffff;
  --fg: #0b0b0b;
  --muted: #5c5c5c;
  --border: #e6e6e6;
  --border-strong: #bdbdbd;
  --focus: #0b0b0b;
  --ok-bg: #f3f3f3;
  --ng-bg: #fff;
}

* { box-sizing: border-box; }
html, body { height: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto,
    "Hiragino Sans", "Noto Sans JP", "Yu Gothic", sans-serif;
  line-height: 1.6;
}

a {
  color: inherit;
  text-decoration: none;
}
a:hover { text-decoration: underline; }

.page {
  min-height: 100%;
  display: grid;
  grid-template-rows: auto 1fr auto;
}

.header {
  max-width: 100%;
  margin: 0 auto;
  width: 100%;
  padding: 18px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
}

.brand {
  font-weight: 700;
  letter-spacing: 0.02em;
}

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

.nav a[aria-current="page"] {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.main {
  max-width: 920px;
  margin: 0 auto;
  width: 100%;
  padding: 110px 16px;
}

.card {
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px;
  background: #fff;
}

.card__head h1 {
  margin: 0;
  font-size: 22px;
  letter-spacing: 0.02em;
}

.card__head p {
  margin: 6px 0 0;
}

.muted { color: var(--muted); }
.req { color: var(--fg); }

.alert {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px 14px;
  margin: 16px 0 18px;
  font-size: 14px;
}

.alert--ok {
  background: var(--ok-bg);
}

.alert--ng {
  background: var(--ng-bg);
  border-color: var(--border-strong);
}

.form { margin-top: 18px; }

.grid {
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr;
}

@media (min-width: 720px) {
  .grid {
    grid-template-columns: 1fr 1fr;
    gap: 16px;
  }
  .field--full { grid-column: 1 / -1; }
}

.field label {
  display: inline-block;
  font-size: 14px;
  margin-bottom: 6px;
}

input, textarea {
  width: 100%;
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  padding: 11px 12px;
  font-size: 16px;
  background: #fff;
  color: var(--fg);
  outline: none;
}

textarea { resize: vertical; min-height: 160px; }

input:focus, textarea:focus {
  border-color: var(--focus);
  box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.12);
}

.help {
  margin: 8px 0 0;
  font-size: 12px;
}

.actions {
  margin-top: 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  border: 1px solid var(--fg);
  background: var(--fg);
  color: #fff;
  border-radius: 999px;
  padding: 12px 16px;
  font-size: 14px;
  cursor: pointer;
  transition: transform 0.05s ease;
}

.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.fineprint {
  margin: 0;
  font-size: 12px;
}

.footer {
  max-width: 920px;
  margin: 0 auto;
  width: 100%;
  padding: 18px 16px;
  border-top: 1px solid var(--border);
  font-size: 12px;
}

.honeypot {
  position: absolute;
  left: -9999px;
  width: 1px;
  height: 1px;
  overflow: hidden;
}