fix: keep presentation toolbar visible on narrow phones

presentations/less-prompting-more-shipping/theme.css

@@ -36,6 +36,7 @@ body{margin:0;background:var(--paper);color:var(--ink)}
 a:focus-visible,button:focus-visible{outline:3px solid #b88719;outline-offset:3px}
 .reveal.deck{height:calc(100dvh - 48px);top:48px}
 @media(max-width:600px){.toolbar{gap:9px;font-size:12px;padding:8px}.toolbar .help{display:none}.toolbar button{padding:6px}.deck .controls{bottom:18px}}
+@media(max-width:360px){.toolbar{gap:4px}}
 /* Portrait is re-composed, not a postage-stamp landscape slide. */
 .portrait .deck .slides section{height:1000px;padding:28px}
 .portrait .deck h1{font-size:64px}.portrait .deck h2{font-size:43px;margin-bottom:24px}