/* Кнопка фоновой музыки (assets/music.js) — слева внизу, напротив альбома наклеек */
.mus-btn { position: fixed; z-index: 899; left: 14px; bottom: calc(env(safe-area-inset-bottom, 0px) + 16px);
  width: 42px; height: 42px; padding: 0; border: 0; border-radius: 50%; cursor: pointer;
  display: flex; align-items: center; justify-content: center; -webkit-tap-highlight-color: transparent;
  background: rgba(255, 248, 238, .92); color: #6B4A36; box-shadow: 0 4px 14px rgba(60, 35, 20, .18), 0 0 0 1px rgba(107, 74, 54, .12);
  -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px); transition: transform .2s, color .2s; }
.mus-btn:active { transform: scale(.92); }
.mus-btn.is-on { color: #B85C38; }
.mus-btn.is-on svg path:not(:first-child) { animation: mus-wave 1.6s ease-in-out infinite; transform-origin: 40% 50%; }
@keyframes mus-wave { 0%, 100% { opacity: .45; } 50% { opacity: 1; } }
@media (max-width: 600px) { .mus-btn { left: 10px; bottom: calc(env(safe-area-inset-bottom, 0px) + 12px); width: 38px; height: 38px; } }
@media (prefers-reduced-motion: reduce) { .mus-btn.is-on svg path { animation: none; } }