.extension-download {
  box-sizing: border-box;
  max-width: 1360px;
  margin: 20px auto;
  padding: 24px 28px;
  border: 1px solid #b5c3ae;
  border-left: 5px solid #285847;
  border-radius: 16px;
  background: #f0f3e9;
  color: #294c42;
}
.extension-download-main { display: flex; align-items: center; justify-content: space-between; gap: 28px; }
.extension-download-tag { font-size: 12px; letter-spacing: .12em; color: #666d46; }
.extension-download h2 { font-size: clamp(19px, 2vw, 26px); line-height: 1.4; margin: 8px 0; }
.extension-download p { line-height: 1.7; margin: 8px 0; }
.extension-download-action { flex: 0 0 260px; text-align: center; }
.extension-download-button {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 10px;
  padding: 16px 22px;
  background: #285847;
  color: #fff;
  border-radius: 10px;
  font-weight: 700;
  font-size: 19px;
  text-decoration: none;
  box-shadow: 0 4px 12px #28584722;
}
.extension-download-button:hover { background: #193f32; }
.extension-download-button:focus-visible, .extension-install-guide summary:focus-visible { outline: 3px solid #b97939; outline-offset: 4px; }
.extension-download-action small { display: block; margin-top: 10px; line-height: 1.6; }
.extension-install-guide { margin-top: 18px; border-top: 1px solid #d1daca; padding-top: 14px; font-size: 14px; }
.extension-install-guide summary { cursor: pointer; font-weight: 600; }
.extension-install-guide li { margin: 10px 0; line-height: 1.7; }
@media (max-width: 1420px) { .extension-download { margin-left: 24px; margin-right: 24px; } }
@media (max-width: 700px) {
  .extension-download { margin: 14px 12px; padding: 20px; }
  .extension-download-main { flex-direction: column; align-items: stretch; gap: 14px; }
  .extension-download-action { flex-basis: auto; }
}