/* Top menu: tools under Approach */
.nav-group { position: relative; display: inline-flex; align-items: center; flex: 0 0 auto; }
.nav-top { display: inline-flex; align-items: center; gap: 2px; }
.nav-toggle {
  position: relative; display: inline-flex; align-items: center; justify-content: center;
  width: 24px; height: 24px; margin: -4px -3px; /* 24px target, same footprint as 18x16 */ padding: 0; border: 0; background: none;
  color: var(--chrome-muted); cursor: pointer;
}
.nav-toggle::before {
  content: ""; width: 6px; height: 6px; margin-top: -3px;
  border-right: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor;
  transform: rotate(45deg); transition: transform .15s;
}
.nav-toggle::after { content: ""; position: absolute; inset: -12px -8px; } /* larger tap area, no layout change */
.nav-toggle:hover, .nav-group.open .nav-toggle { color: var(--chrome-ink); }
.nav-group.open .nav-toggle::before { transform: rotate(-135deg); margin-top: 3px; }
.nav-toggle:focus-visible, .nav-sub a:focus-visible { outline: 2px solid var(--red); outline-offset: 2px; }
.nav-sub { display: none; }
.nav-sub a { display: block; }
.nav-sep { display: block; height: 0; border-top: 1px solid #3a3a40; }

@media (min-width: 861px) {
  .nav-sub {
    position: absolute; top: 100%; left: -14px; z-index: 30;
    padding-top: 12px; min-width: max-content;
  }
  .nav-sub-inner {
    display: block; background: var(--chrome); border: 1px solid #2a2a2e; border-top: 2px solid var(--red);
    padding: 6px 0; box-shadow: 0 10px 24px rgba(0,0,0,.25);
  }
  .nav-sub a { padding: 9px 14px; }
  .nav-sep { margin: 6px 14px; }
  .nav-group:hover .nav-sub, .nav-group.open .nav-sub { display: block; }
  .nav-group:hover .nav-toggle { color: var(--chrome-ink); }
}

@media (max-width: 860px) {
  .nav-group { display: contents; }
  .nav-group.open .nav-sub {
    display: block; grid-column: 1 / -1;
    width: 0; min-width: 100%; box-sizing: border-box; /* do not widen the menu columns */
    border-left: 2px solid var(--red); padding: 2px 0 2px 12px;
  }
  .nav-sub a { padding: 4px 0; }
  .nav-sep { margin: 4px 0; width: 120px; }
}

/* Phone: logo plus a menu button; the links open below. */
.menu-btn { display: none; }
@media (max-width: 860px) {
  .chrome-inner:has(.menu-btn) { align-items: center; }
  .menu-btn {
    display: inline-flex; align-items: center; justify-content: center;
    width: 44px; height: 44px; margin: 0 -10px 0 auto; padding: 0;
    border: 0; background: none; color: var(--chrome-ink); cursor: pointer;
  }
  .menu-btn span, .menu-btn span::before, .menu-btn span::after {
    display: block; width: 22px; height: 2px; background: currentColor;
    transition: transform .15s, background-color .15s;
  }
  .menu-btn span { position: relative; }
  .menu-btn span::before, .menu-btn span::after { content: ""; position: absolute; left: 0; }
  .menu-btn span::before { top: -7px; }
  .menu-btn span::after { top: 7px; }
  .menu-btn[aria-expanded="true"] span { background: transparent; }
  .menu-btn[aria-expanded="true"] span::before { transform: translateY(7px) rotate(45deg); }
  .menu-btn[aria-expanded="true"] span::after { transform: translateY(-7px) rotate(-45deg); }
  .menu-btn:focus-visible { outline: 2px solid var(--red); outline-offset: -4px; }
  .chrome-inner:has(.menu-btn) nav { display: none; }
  .chrome-inner.menu-open nav {
    display: grid; padding: 4px 4px 6px; margin: 0 -4px; box-sizing: border-box;
    width: calc(100% + 8px); flex-basis: calc(100% + 8px);
    /* Never taller than the screen below the bar (8px is the gap above the links). */
    max-height: calc(100vh - var(--menu-h, 63px) - 8px);
    max-height: calc(100dvh - var(--menu-h, 63px) - 8px);
    overflow-x: hidden; overflow-y: auto; overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
  }
}

/* Jump links and headings stop clear of the pinned top menu. */
[id], :target, h1, h2, h3, h4 { scroll-margin-top: calc(var(--menu-h, 65px) + 16px); }