:root {
  --bg: #ffffff;
  --fg: #111111;
  --muted: #6b7280;
  --border: #e5e7eb;
  --soft: #f5f5f5;
  --accent: #000000;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--fg); font-family: var(--font); -webkit-text-size-adjust: 100%; }
body { padding-bottom: 56px; }

.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 20px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}
.topbar .brand { font-weight: 600; font-size: 0.95rem; letter-spacing: 0.01em; }

.container {
  max-width: 480px;
  margin: 0 auto;
  padding: 20px;
}

.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px 22px;
  margin-bottom: 16px;
}
.card h1 { font-size: 1.15rem; margin: 0 0 12px; font-weight: 600; }
.card h2 { font-size: 0.95rem; margin: 18px 0 6px; font-weight: 600; }
.card p  { font-size: 0.92rem; line-height: 1.5; margin: 0 0 10px; }

.label {
  text-transform: uppercase;
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.02em;
  margin-bottom: 6px;
}

.hint {
  font-size: 0.78rem;
  color: var(--muted);
  margin: 8px 0 0;
}

.field-label {
  display: block;
  text-transform: uppercase;
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.02em;
  margin: 4px 0 6px;
}

input[type="text"] {
  width: 100%;
  font: inherit;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  color: var(--fg);
  outline: none;
  min-height: 44px;
}
input[type="text"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(0,0,0,0.06);
}

.btn {
  display: inline-block;
  width: 100%;
  margin-top: 12px;
  padding: 12px 14px;
  font: inherit;
  font-weight: 500;
  background: var(--accent);
  color: #fff;
  border: 1px solid var(--accent);
  border-radius: 8px;
  cursor: pointer;
  min-height: 44px;
}
.btn:hover { background: #222; border-color: #222; }
.btn:active { transform: translateY(1px); }

.result {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--soft);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  font-family: var(--mono);
  font-size: 1rem;
  word-break: break-word;
}
.result .value { flex: 1; }
.copy {
  font: inherit;
  font-size: 0.8rem;
  padding: 6px 10px;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  border-radius: 6px;
  cursor: pointer;
  min-height: 32px;
  white-space: nowrap;
}
.copy.done { background: #fff; color: var(--accent); }

.meta {
  font-size: 0.78rem;
  color: var(--muted);
  margin-top: 10px;
  word-break: break-all;
}
.meta code { font-family: var(--mono); }

.note {
  font-size: 0.85rem;
  color: var(--muted);
  background: var(--soft);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  margin: 0 0 16px;
}

.legal {
  position: fixed; bottom: 0; left: 0; right: 0;
  text-align: center;
  font-size: 0.75rem;
  color: var(--muted);
  padding: 8px 12px;
  background: #fff;
  border-top: 1px solid var(--border);
}
.legal a { color: var(--muted); text-decoration: underline; }
.legal a:hover { color: var(--fg); }

@media (max-width: 480px) {
  .container { padding: 14px; }
  .card { padding: 16px; }
  .result { flex-direction: column; align-items: stretch; }
  .copy { width: 100%; }
}