html {
  --a11y-control-border: rgba(255, 255, 255, .36);
  background: #000;
}

.button.secondary,
.language-switcher {
  border-color: var(--a11y-control-border);
}

.mobile-nav-toggle,
.mobile-nav-panel {
  display: none;
}

@media (max-width: 900px) {
  html {
    scroll-padding-top: calc(65px + env(safe-area-inset-top));
  }

  .site-header {
    background: #000;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    padding-top: env(safe-area-inset-top);
  }

  .header-inner {
    min-height: 64px;
  }

  .language-switcher {
    flex: 0 0 auto;
  }

  .lang-link {
    min-width: 44px;
    min-height: 44px;
  }

  .mobile-nav-ready .brand {
    display: none;
  }

  .mobile-nav-ready .mobile-nav-toggle {
    width: 44px;
    height: 44px;
    display: inline-flex;
    flex: 0 0 auto;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    padding: 0;
    border: 1px solid var(--a11y-control-border);
    border-radius: 12px;
    color: var(--text);
    background: rgba(255, 255, 255, .035);
    cursor: pointer;
  }

  .mobile-nav-toggle-line {
    width: 19px;
    height: 2px;
    display: block;
    border-radius: 999px;
    background: currentColor;
    transition: transform .2s ease, opacity .2s ease;
  }

  .mobile-nav-toggle[aria-expanded="true"] .mobile-nav-toggle-line:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .mobile-nav-toggle[aria-expanded="true"] .mobile-nav-toggle-line:nth-child(2) {
    opacity: 0;
  }

  .mobile-nav-toggle[aria-expanded="true"] .mobile-nav-toggle-line:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .mobile-nav-panel {
    position: absolute;
    top: 100%;
    right: 0;
    left: 0;
    z-index: 99;
    display: grid;
    gap: 2px;
    padding: 10px max(14px, env(safe-area-inset-right)) 16px max(14px, env(safe-area-inset-left));
    border-bottom: 1px solid var(--a11y-control-border);
    background: #000;
    box-shadow: 0 24px 48px rgba(0, 0, 0, .36);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-8px);
    transition: opacity .18s ease, transform .18s ease, visibility .18s ease;
  }

  .mobile-nav-panel.is-open {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
  }

  .mobile-nav-panel a {
    min-height: 48px;
    display: flex;
    align-items: center;
    padding: 0 14px;
    border-radius: 10px;
    color: var(--text);
    text-decoration: none;
    font-size: 15px;
    font-weight: 700;
  }

  .mobile-nav-panel a:hover,
  .mobile-nav-panel a:focus-visible {
    background: rgba(255, 255, 255, .10);
  }
}

@media (max-width: 640px) {
  .hero-actions {
    display: grid;
    grid-template-columns: 1fr;
  }

  .hero-actions > .button {
    width: 100%;
  }

  .hero-actions > .button[href^="mailto:"] {
    display: none;
  }

  .eyebrow {
    font-size: 13px;
    letter-spacing: .11em;
    line-height: 1.45;
  }

  .hero-grid > div:first-child > .hero-proof {
    font-size: 12px;
    line-height: 1.5;
  }

  .hero-metrics span {
    font-size: 11px;
    line-height: 1.35;
  }

  .card-topline {
    gap: 12px;
    font-size: 12px;
    line-height: 1.4;
  }

  .tags span,
  .architecture-lab-meta span {
    font-size: 12px;
  }

  .focus-list span {
    font-size: 13px;
  }

  .signal-kicker {
    font-size: 12px;
    line-height: 1.4;
  }

  .signal-line span {
    font-size: 13px;
  }

  .trajectory-grid article > span,
  .writing-cards span,
  .practice-card > span,
  .impact-result strong {
    font-size: 12px;
    line-height: 1.45;
  }

  .principles article > span {
    font-size: 13px;
  }

  .site-footer {
    font-size: 13px;
  }
}