.site-back-top{position:fixed;right:max(18px,env(safe-area-inset-right));bottom:max(18px,env(safe-area-inset-bottom));z-index:30;display:grid;place-items:center;width:48px;height:48px;padding:0;border:1px solid #89a7b9;border-radius:50%;background:#15232ef2;color:#fff;box-shadow:0 4px 18px #0007;cursor:pointer;touch-action:manipulation}
.site-back-top[hidden],body.is-measuring .site-back-top{display:none}
.site-back-top:hover{background:#223b4c;border-color:#a3e9f1}
.site-back-top:focus-visible{outline:3px solid #7ee8ef;outline-offset:4px}
.site-back-top svg{width:23px;height:23px;fill:none;stroke:currentColor;stroke-width:2.3;stroke-linecap:round;stroke-linejoin:round}
body:has(dialog[open]) .site-back-top,body:has([aria-modal="true"]) .site-back-top{visibility:hidden}

/* The existing playlist gradient now identifies Google Play installation. */
[data-install-mobile],.mobile-premium-download,.hero .install-button,.button.primary[href*="play.google.com/store/apps/details"]{
 border:1px solid rgb(103 232 249 / .8);background:linear-gradient(110deg,#08d9f4 0%,#1686ff 48%,#b43cff 100%);color:#fff;
 box-shadow:0 0 18px rgb(8 217 244 / .32),0 0 34px rgb(180 60 255 / .2),inset 0 1px 0 rgb(255 255 255 / .42);text-shadow:0 1px 2px rgb(0 0 30 / .45)
}
[data-install-mobile]:hover,.mobile-premium-download:hover,.hero .install-button:hover,.button.primary[href*="play.google.com/store/apps/details"]:hover{background:linear-gradient(110deg,#08d9f4 0%,#1686ff 48%,#b43cff 100%);border-color:#a5f3fc;filter:brightness(1.08)}
[data-install-mobile]:focus-visible,.mobile-premium-download:focus-visible,.hero .install-button:focus-visible,.button.primary[href*="play.google.com/store/apps/details"]:focus-visible{outline:3px solid #a5f3fc;outline-offset:4px}
@media(prefers-reduced-motion:no-preference){
 [data-install-mobile],.mobile-premium-download,.hero .install-button,.button.primary[href*="play.google.com/store/apps/details"]{animation:install-gradient-glow 3.6s ease-in-out infinite}
 @keyframes install-gradient-glow{0%,100%{box-shadow:0 0 12px #08d9f43d,0 0 22px #b43cff26,inset 0 1px 0 #ffffff6b}50%{box-shadow:0 0 24px #08d9f480,0 0 42px #b43cff59,inset 0 1px 0 #ffffff80}}
}