:root {
  color-scheme: dark;
  --background: #111816;
  --surface: #1a2420;
  --text: #f1f4ef;
  --muted: #b4c2b9;
  --accent: #c0e9a1;
  --line: #334139;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--background);
  color: var(--text);
  font-synthesis: none;
  -webkit-text-size-adjust: 100%;
}
* { box-sizing: border-box; }
body { margin: 0; font-size: 16px; line-height: 1.65; }
::selection { background: var(--accent); color: var(--background); }
.site-header, main, footer { width: min(100% - 48px, 760px); margin-inline: auto; }
.site-header { display: flex; justify-content: space-between; align-items: center; gap: 20px; padding-block: 28px; border-bottom: 1px solid var(--line); }
.brand { font-size: 18px; font-weight: 800; letter-spacing: .08em; }
.brand-detail { margin-left: 8px; color: var(--muted); font-size: 11px; font-weight: 500; letter-spacing: .12em; }
.services { color: var(--muted); font-size: 13px; }
.notice { padding-block: 56px 40px; }
h1 { max-width: 680px; margin: 0 0 24px; font-size: clamp(2.25rem, 6vw, 3.5rem); line-height: 1.12; font-weight: 700; letter-spacing: -.035em; text-wrap: balance; }
h1 span { color: var(--accent); }
p { margin: 0; color: var(--muted); }
.intro { max-width: 62ch; font-size: 18px; }
.unlimited { margin-top: 12px; color: var(--text); }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 20px; min-height: 52px; margin-top: 28px; padding: 13px 22px; border-radius: 8px; background: var(--accent); color: var(--background); font-weight: 700; line-height: 1.4; text-decoration: none; transition: background-color .15s ease-out; }
.button:hover { background: #d5f4be; }
.button:active { background: #acd58e; }
.button:focus-visible { outline: 3px solid var(--text); outline-offset: 5px; }
.button svg { flex-shrink: 0; }
.sign-in-note { margin-top: 12px; font-size: 13px; }
h2 { margin: 0 0 16px; font-size: 20px; line-height: 1.3; font-weight: 650; letter-spacing: -.015em; }
strong { color: var(--text); font-weight: 650; }
.how-to { border-top: 1px solid var(--line); padding-block: 32px; }
ol { display: grid; gap: 12px; margin: 0; padding-left: 24px; color: var(--muted); }
li { padding-left: 8px; }
li::marker { color: var(--accent); font-weight: 650; }
.details { display: grid; grid-template-columns: 1.35fr 1fr; gap: 40px; padding-block: 32px; border-top: 1px solid var(--line); }
.details p + p, .help p + p { margin-top: 12px; }
.help { margin-block: 4px 36px; padding: 24px; border-radius: 12px; background: var(--surface); font-size: 14px; }
.help h2 { font-size: 18px; margin-bottom: 12px; }
footer { display: flex; justify-content: space-between; gap: 16px; padding-block: 20px 28px; border-top: 1px solid var(--line); color: var(--muted); font-size: 12px; }
@media (max-width: 540px) {
  .site-header, main, footer { width: calc(100% - 40px); }
  .site-header { align-items: flex-start; flex-direction: column; gap: 4px; padding-block: 20px; }
  .notice { padding-top: 36px; }
  .intro { font-size: 16px; }
  .button { width: 100%; }
  .details { grid-template-columns: 1fr; gap: 28px; }
  .help { padding: 20px; }
  footer { flex-wrap: wrap; gap: 4px 16px; }
}
@media (prefers-reduced-motion: reduce) { .button { transition: none; } }