/* ---------- Nút nổi góc phải: menu (dưới) + nhạc (trên) ---------- */
.fab {
  position: fixed; z-index: 40;
  right: max(16px, env(safe-area-inset-right));
  width: 48px; height: 48px;
  display: grid; place-items: center;
  border: 1px solid var(--line); border-radius: 50%;
  background: rgba(255, 255, 255, .94); color: var(--ink);
  box-shadow: 0 4px 16px rgba(31, 29, 27, .14);
  cursor: pointer;
}
.fab:hover, .fab:focus-visible { background: var(--ink); color: var(--bg); }
.menu-toggle { bottom: max(16px, env(safe-area-inset-bottom)); }
.music-toggle { bottom: calc(max(16px, env(safe-area-inset-bottom)) + 60px); }
/* 2 trạng thái: tắt = nốt nhạc gạch chéo; đang phát = nốt nhạc nền đậm + sóng lan ra */
.music-toggle__icon--on { display: none; }
.music-toggle.is-playing .music-toggle__icon--off { display: none; }
.music-toggle.is-playing .music-toggle__icon--on { display: block; animation: bob 1.2s ease-in-out infinite; }
.music-toggle.is-playing { background: var(--accent); border-color: var(--accent); color: #fff; }
.music-toggle.is-playing::before, .music-toggle.is-playing::after {
  content: ""; position: absolute; inset: -1px;
  border: 1px solid var(--accent); border-radius: 50%;
  animation: ripple 2s ease-out infinite;
  pointer-events: none;
}
.music-toggle.is-playing::after { animation-delay: 1s; }
@keyframes ripple { from { transform: scale(1); opacity: .7; } to { transform: scale(1.8); opacity: 0; } }
@keyframes bob { 50% { transform: translateY(-2px) rotate(-6deg); } }

/* Gợi ý cạnh nút nhạc */
.music-hint {
  position: fixed; z-index: 40;
  right: calc(max(16px, env(safe-area-inset-right)) + 60px);
  bottom: calc(max(16px, env(safe-area-inset-bottom)) + 70px);
  margin: 0; padding: .5rem .85rem;
  background: var(--ink); color: var(--bg);
  border-radius: 999px;
  font-size: var(--fs-sm); white-space: nowrap;
  box-shadow: 0 4px 16px rgba(31, 29, 27, .2);
  animation: hint-in .3s ease-out;
}
@keyframes hint-in { from { opacity: 0; transform: translateX(8px); } }
.fab .line-icon svg { width: 22px; height: 22px; }

.menu-panel {
  position: fixed; z-index: 41;
  right: max(16px, env(safe-area-inset-right));
  bottom: calc(max(16px, env(safe-area-inset-bottom)) + 60px);
  min-width: 220px;
  padding: .5rem;
  background: var(--surface);
  border: 1px solid var(--line); border-radius: 14px;
  box-shadow: 0 12px 40px rgba(31, 29, 27, .18);
}
/* Có nút nhạc thì đẩy menu lên trên nút nhạc */
body:has(.music-toggle:not([hidden])) .menu-panel { bottom: calc(max(16px, env(safe-area-inset-bottom)) + 120px); }
.menu__list { list-style: none; margin: 0; padding: 0; }
.menu__link {
  display: flex; align-items: center;
  min-height: 44px; padding: .5rem .9rem;
  border-radius: 8px;
  color: var(--ink); text-decoration: none; font-size: var(--fs-md);
}
.menu__link:hover, .menu__link:focus-visible { background: var(--tint); }

/* ---------- A10. Trái tim rơi suốt trang ---------- */
.hearts { position: fixed; inset: 0; z-index: 60; width: 100%; height: 100%; pointer-events: none; }

@media (prefers-reduced-motion: reduce) {
  .music-toggle.is-playing .music-toggle__icon--on, .music-toggle.is-playing::before,
  .music-toggle.is-playing::after, .music-hint { animation: none; }
}