/* background = top of the sky, shown until the first frame is drawn */
:root { --bg: #86bff0; }
@media (prefers-color-scheme: dark) { :root { --bg: #040914; } }

/* one fixed, full-screen canvas; nothing scrolls, no pull-to-refresh or rubber-banding on phones */
html, body { margin: 0; height: 100%; overflow: hidden; overscroll-behavior: none; background: var(--bg); }
canvas {
    position: fixed; inset: 0;
    width: 100%;
    height: 100vh;      /* fallback */
    height: 100dvh;     /* follows the mobile address bar */
    display: block; outline: none;
    touch-action: none; /* taps still click the fish, swipes don't scroll the page */
}