html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}
body {
  overflow-x: hidden;
  padding-bottom: max(24px, env(safe-area-inset-bottom));
}
header, main, footer {
  width: min(760px, calc(100% - 24px));
}
.lang-switch {
  position: absolute;
  top: max(10px, env(safe-area-inset-top));
  right: max(10px, env(safe-area-inset-right));
  z-index: 10;
}
html[dir="rtl"] .lang-switch {
  right: max(10px, env(safe-area-inset-right));
  left: auto;
}
.lang-switch select {
  width: auto;
  min-width: 7.5rem;
  min-height: 40px;
  font: inherit;
  font-size: 16px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--card);
  color: var(--ink);
  cursor: pointer;
}
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
}
input, textarea, select {
  font-size: 16px;
  min-height: 44px;
}
textarea { min-height: 160px; }
.tabs button,
.presets button,
.ai-btn,
button {
  min-height: 44px;
}
.formula {
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  word-break: break-word;
}
.ai-row {
  display: grid;
  gap: 8px;
}
.ai-btn {
  font: inherit;
  font-weight: 650;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: var(--accent-ink);
  border-radius: 12px;
  padding: 12px 16px;
  cursor: pointer;
  width: 100%;
}
.ai-btn:active { opacity: 0.88; }
.ai-btn[disabled] { opacity: 0.7; cursor: default; }
.toast {
  position: fixed;
  left: 50%;
  bottom: max(20px, env(safe-area-inset-bottom));
  transform: translateX(-50%);
  background: var(--ink);
  color: #fff;
  padding: 12px 16px;
  border-radius: 12px;
  font-size: 0.92rem;
  max-width: min(92vw, 420px);
  z-index: 40;
  box-shadow: none;
}
.toast[hidden] { display: none !important; }
.stats-chip {
  position: fixed;
  left: 10px;
  bottom: max(12px, env(safe-area-inset-bottom));
  top: auto;
  z-index: 30;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 8px 10px;
  font-size: 0.75rem;
  color: var(--muted);
  max-width: 70vw;
  pointer-events: none;
}
.presets { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
@media (max-width: 640px) {
  .presets {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: stretch;
  }
  .presets .note {
    grid-column: 1 / -1;
  }
  .presets button {
    flex: none;
    width: 100%;
  }
}
@media (max-width: 640px) {
  header { padding: 58px 0 6px; }
  h1 { font-size: 1.5rem; line-height: 1.28; letter-spacing: -0.02em; }
  .lede { font-size: 0.95rem; line-height: 1.55; margin-bottom: 16px; }
  .kicker { font-size: 0.72rem; }
  .panel { padding: 14px; border-radius: 12px; }
  .grid { grid-template-columns: 1fr !important; }
  .tabs { flex-direction: column; }
  .tabs button { width: 100%; }
  .presets { gap: 8px; }
  .presets button { flex: 1 1 calc(50% - 8px); }
  .big { font-size: 2rem; }
  footer { font-size: 0.82rem; padding: 8px 0 40px; }
  footer p { line-height: 1.6; }
}
@media (max-width: 380px) {
  h1 { font-size: 1.35rem; }
  .lang-switch select { min-width: 6.4rem; padding: 8px 8px; }
}