:root {
  color-scheme: light;
  --ink: #1c1917;
  --muted: #57534e;
  --line: #e7e5e4;
  --paper: #fafaf9;
  --accent: #9a3412;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Hiragino Sans", "Noto Sans JP", sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.7;
}

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 16px 24px;
  border-bottom: 1px solid var(--line);
  background: #fff;
}

.brand {
  color: inherit;
  font-weight: 700;
  text-decoration: none;
}

nav { display: flex; gap: 16px; }
nav a { color: var(--muted); }

main {
  max-width: 40rem;
  margin: 0 auto;
  padding: 48px 24px;
}

h1 { font-size: 1.75rem; line-height: 1.3; margin: 0 0 16px; }

.button, button {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  border: 0;
  border-radius: 6px;
  padding: 10px 16px;
  font: inherit;
  cursor: pointer;
}

form { display: grid; gap: 14px; }
label { display: grid; gap: 4px; font-size: 0.95rem; }
input, textarea {
  font: inherit;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
}
.note, .error, .ok { color: var(--muted); }
.error { color: #9f1239; }
.ok { color: #166534; }
.hp { position: absolute; left: -9999px; }