:root {
  --bg: #f8f9fb;
  --surface: #ffffff;
  --text: #1a1d26;
  --muted: #5c6370;
  --accent: #2d6cdf;
  --border: #e2e6ee;
  --max: 42rem;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 1rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 1.5rem;
}

header .wrap {
  max-width: var(--max);
  margin: 0 auto;
}

header a {
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 1.05rem;
}

header a:hover {
  color: var(--accent);
}

main {
  max-width: var(--max);
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
}

h1 {
  font-size: 1.75rem;
  line-height: 1.25;
  margin: 0 0 0.5rem;
}

.meta {
  color: var(--muted);
  font-size: 0.9rem;
  margin-bottom: 2rem;
}

h2 {
  font-size: 1.15rem;
  margin: 2rem 0 0.75rem;
}

p,
li {
  color: var(--text);
}

ul {
  padding-left: 1.25rem;
}

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

footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1.5rem 2.5rem;
  color: var(--muted);
  font-size: 0.875rem;
}

footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  margin-bottom: 0.75rem;
}

.notice {
  background: #fff8e6;
  border: 1px solid #f0d78c;
  border-radius: 8px;
  padding: 0.85rem 1rem;
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
}

.sample-msg {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.1rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.9rem;
}

.optin-demo {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem 1.35rem;
  margin: 1rem 0 2rem;
}

.optin-brand {
  font-weight: 700;
  font-size: 1.05rem;
  margin: 0 0 1rem;
}

.field-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.4rem;
}

.field-input {
  width: 100%;
  font: inherit;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 1rem;
}

.optin-disclosure {
  font-size: 0.92rem;
  color: var(--muted);
  margin: 0 0 1rem;
}

.consent-row {
  display: flex;
  gap: 0.65rem;
  align-items: flex-start;
  font-size: 0.92rem;
  margin-bottom: 1.1rem;
  cursor: pointer;
}

.consent-row input {
  margin-top: 0.2rem;
  flex-shrink: 0;
  width: 1.1rem;
  height: 1.1rem;
}

.btn-primary {
  width: 100%;
  font: inherit;
  font-weight: 600;
  padding: 0.75rem 1rem;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
}

.btn-primary:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.optin-note {
  font-size: 0.9rem;
  margin-top: 0.85rem;
  color: var(--muted);
}

.optin-note.success {
  color: #1a6b3c;
}

.screenshot {
  margin: 1rem 0 1.5rem;
}

.screenshot img {
  max-width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 12px;
  display: block;
}

.screenshot figcaption {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--muted);
}