/* Floating light/dark/auto picker, bottom right. Added 2026-10-22. Dark-mode colours live in dark.css. */
.theme-toggle {
    position: fixed; right: 18px; bottom: 18px; z-index: 9000;
    width: 38px; height: 38px; padding: 0; margin: 0;
    border-radius: 50%; border: 1px solid rgba(0,0,0,0.2);
    background: rgba(255,255,255,0.88); color: #444;
    box-shadow: 0 1px 4px rgba(0,0,0,0.25);
    cursor: pointer; opacity: 0.7;
    display: flex; align-items: center; justify-content: center;
    transition: opacity 0.2s, transform 0.2s;
}
.theme-toggle:hover, .theme-toggle:focus-visible { opacity: 1; transform: scale(1.06); outline: none; }
.theme-toggle svg {
    width: 20px; height: 20px; display: none;
    fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round;
}
html[data-theme="light"] .theme-toggle .tt-light,
html[data-theme="dark"]  .theme-toggle .tt-dark,
html:not([data-theme="light"]):not([data-theme="dark"]) .theme-toggle .tt-auto { display: block; }
@media print { .theme-toggle { display: none; } }