.m19-install-prompt,
.m19-install-guide {
  --m19-install-blue: #1167ed;
  --m19-install-navy: #0b1f3a;
  --m19-install-text: #17243a;
  --m19-install-muted: #64748b;
  font-family: inherit;
}

body.m19-install-guide-open { overflow: hidden; }

.m19-install-prompt[hidden],
.m19-install-guide[hidden] { display: none !important; }

.m19-install-prompt {
  position: fixed;
  left: max(16px, env(safe-area-inset-left));
  bottom: max(16px, env(safe-area-inset-bottom));
  z-index: 12050;
  width: min(460px, calc(100vw - 32px));
  padding: 16px;
  color: var(--m19-install-text);
  background: rgba(255, 255, 255, .98);
  border: 1px solid rgba(17, 103, 237, .20);
  border-radius: 20px;
  box-shadow: 0 22px 70px rgba(11, 31, 58, .25);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  transform: translateY(calc(100% + 36px));
  opacity: 0;
  transition: transform .28s ease, opacity .22s ease;
}

.m19-install-prompt.is-visible { transform: translateY(0); opacity: 1; }

.m19-install-prompt__top {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr) 34px;
  gap: 13px;
  align-items: start;
}

.m19-install-prompt__icon {
  width: 54px;
  height: 54px;
  display: block;
  border-radius: 14px;
  box-shadow: 0 7px 20px rgba(11, 31, 58, .16);
}

.m19-install-prompt__copy strong {
  display: block;
  margin: 1px 0 5px;
  color: var(--m19-install-navy);
  font-size: 16px;
  line-height: 1.25;
}

.m19-install-prompt__copy p {
  margin: 0;
  color: var(--m19-install-muted);
  font-size: 13px;
  line-height: 1.45;
}

.m19-install-prompt__close {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  padding: 0;
  color: #718096;
  background: #f4f7fb;
  border: 0;
  border-radius: 10px;
  cursor: pointer;
  font: inherit;
  font-size: 21px;
  line-height: 1;
}

.m19-install-prompt__close:hover { color: var(--m19-install-navy); background: #eaf1fa; }

.m19-install-prompt__actions {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
  margin-top: 14px;
}

.m19-install-prompt__button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 17px;
  border-radius: 12px;
  border: 1px solid transparent;
  cursor: pointer;
  font: inherit;
  font-size: 13px;
  font-weight: 800;
}

.m19-install-prompt__button--primary {
  color: #fff;
  background: linear-gradient(135deg, #0d5edb, #1674ff);
  box-shadow: 0 9px 22px rgba(17, 103, 237, .24);
}

.m19-install-prompt__button--primary:hover { filter: brightness(1.04); }

.m19-install-prompt__button--secondary {
  color: #31506f;
  background: #f5f8fc;
  border-color: #dce6f0;
}

.m19-install-prompt__note {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 10px;
  color: #7b8b9d;
  font-size: 11px;
  line-height: 1.35;
}

.m19-install-prompt__note svg {
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
}

.m19-install-guide {
  position: fixed;
  inset: 0;
  z-index: 12060;
  display: grid;
  place-items: center;
  padding: 18px;
  background: rgba(7, 22, 40, .58);
  backdrop-filter: blur(5px);
  -webkit-backdrop-filter: blur(5px);
}

.m19-install-guide__card {
  width: min(430px, 100%);
  padding: 22px;
  color: var(--m19-install-text);
  background: #fff;
  border-radius: 22px;
  box-shadow: 0 28px 90px rgba(5, 20, 38, .34);
}

.m19-install-guide__head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.m19-install-guide__head img { width: 48px; height: 48px; border-radius: 13px; }
.m19-install-guide__head strong { display: block; color: var(--m19-install-navy); font-size: 18px; }
.m19-install-guide__head span { display: block; margin-top: 3px; color: var(--m19-install-muted); font-size: 12px; }

.m19-install-guide__steps {
  display: grid;
  gap: 11px;
  margin: 0 0 18px;
  padding: 0;
  list-style: none;
}

.m19-install-guide__steps li {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 10px;
  align-items: center;
  color: #3e5269;
  font-size: 13px;
  line-height: 1.45;
}

.m19-install-guide__steps b {
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  color: #fff;
  background: var(--m19-install-blue);
  border-radius: 50%;
  font-size: 12px;
}

.m19-install-guide__browser-note {
  margin: 0 0 18px;
  padding: 14px;
  color: #3e5269;
  background: #f4f8fd;
  border: 1px solid #dce8f5;
  border-radius: 14px;
  font-size: 13px;
  line-height: 1.55;
}

.m19-install-guide__done {
  width: 100%;
  min-height: 46px;
  color: #fff;
  background: var(--m19-install-blue);
  border: 0;
  border-radius: 12px;
  cursor: pointer;
  font: inherit;
  font-size: 14px;
  font-weight: 800;
}

@media (max-width: 640px) {
  .m19-install-prompt {
    left: max(10px, env(safe-area-inset-left));
    right: max(10px, env(safe-area-inset-right));
    bottom: max(10px, env(safe-area-inset-bottom));
    width: auto;
    padding: 14px;
    border-radius: 18px;
  }

  .m19-install-prompt__top { grid-template-columns: 48px minmax(0, 1fr) 32px; gap: 10px; }
  .m19-install-prompt__icon { width: 48px; height: 48px; border-radius: 12px; }
  .m19-install-prompt__copy strong { font-size: 15px; }
  .m19-install-prompt__copy p { font-size: 12px; }
  .m19-install-prompt__actions { grid-template-columns: minmax(0, 1fr) auto; }
  .m19-install-prompt__button { min-height: 42px; padding: 0 14px; font-size: 12px; }
}

@media (max-width: 380px) {
  .m19-install-prompt__actions { grid-template-columns: 1fr; }
  .m19-install-prompt__button { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  .m19-install-prompt { transition: none; }
}

/* Этап 3 (G1): баннер установки никогда не перекрывает главную кнопку */
@media (max-width: 760px) {
  .m19-install-prompt { bottom: calc(max(16px, env(safe-area-inset-bottom)) + 76px); }
  .home-reference-page .m19-install-prompt { bottom: calc(max(16px, env(safe-area-inset-bottom)) + 84px); }
}
@media (max-width: 760px) {
  body.m19-install-open .m19-problem-open { display: none; }
}