* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #0f0f0f;
  color: #e8e8e8;
  line-height: 1.6;
  display: flex;
  justify-content: center;
  padding: 48px 20px;
}
main { max-width: 900px; width: 100%; }
.lang {
  display: flex;
  gap: 6px;
  margin-bottom: 28px;
}
.lang button {
  background: #1a1a1a;
  color: #999;
  border: 1px solid #2a2a2a;
  border-radius: 6px;
  padding: 5px 11px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: color .15s, border-color .15s;
}
.lang button:hover { color: #e8e8e8; }
.lang button.active { color: #53fc18; border-color: #53fc18; }
h1 { font-size: 32px; margin-bottom: 8px; }
.tag { color: #53fc18; font-size: 14px; font-weight: 600; margin-bottom: 24px; }
p { color: #b5b5b5; margin-bottom: 16px; }
h2 { font-size: 18px; margin: 32px 0 10px; color: #fff; }
.terms {
  font-size: 14px;
  color: #999;
  background: #1a1a1a;
  border-left: 3px solid #53fc18;
  border-radius: 6px;
  padding: 16px 18px;
  margin-top: 10px;
}
.demo {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  border: 1px solid #2a2a2a;
  border-radius: 6px;
  overflow: hidden;
  margin-top: 10px;
}
.demo iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}
.desc {
  margin-bottom: 4px;
}
.partner { font-size: 13px; color: #777; }
.partner a { color: #999; font-weight: 600; text-decoration: none; }
.partner a:hover { color: #53fc18; }
a { color: #53fc18; }
footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin-top: 40px;
  font-size: 13px;
  color: #666;
}
footer nav { display: flex; flex-wrap: wrap; gap: 8px 16px; }
footer a { color: #888; text-decoration: none; }
footer a:hover { color: #53fc18; }

@media (max-width: 620px) {
  body { padding-top: 28px; }
  .lang { flex-wrap: wrap; }
  footer { align-items: flex-start; flex-direction: column; }
}