/* ========= STAGE 3 – CELEBRATION ========= */
#stage-3 { background: var(--bg-primary); }
#confetti-container {
    position: fixed; inset: 0; pointer-events: none; z-index: 4; overflow: hidden;
}
.confetti-piece {
    position: absolute; width: 10px; height: 10px;
    top: -20px; animation: confetti-fall linear forwards;
}
.celebration-text { position: relative; z-index: 5; }
.emoji-pop {
    position: absolute; font-size: 2rem; opacity: 0;
    animation: emoji-burst 0.6s ease-out forwards;
}
.e1 { top: -60px; left: -40px; animation-delay: 0.2s; }
.e2 { top: -80px; left: 30px; animation-delay: 0.4s; }
.e3 { top: -50px; right: -30px; animation-delay: 0.6s; }
.e4 { top: 20px; left: -70px; animation-delay: 0.8s; }
.e5 { top: -30px; right: -60px; animation-delay: 1s; }
.e6 { top: 40px; right: -50px; animation-delay: 1.2s; }
.birthday-title { position: relative; }
.bt-line { display: block; opacity: 0; animation: scale-in 0.6s ease-out forwards; }
.bt-line1 { font-size: 3rem; animation-delay: 0.3s; }
.bt-line2 {
    font-family: var(--font-heading); font-size: clamp(2rem, 7vw, 3.5rem);
    font-weight: 800;
    background: linear-gradient(90deg, var(--neon-pink), var(--neon-cyan), var(--gold));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text; animation-delay: 0.6s; line-height: 1.3;
}
.bt-line3 {
    font-family: var(--font-display); font-size: clamp(2.5rem, 9vw, 5rem);
    color: var(--neon-pink);
    text-shadow: 0 0 30px var(--neon-pink), 0 0 80px rgba(255,45,149,0.3);
    animation-delay: 0.9s; line-height: 1.4;
}
.bt-line4 { font-size: 3rem; animation-delay: 1.2s; }
.next-btn {
    margin-top: 36px; padding: 14px 36px;
    border: 2px solid var(--neon-cyan); border-radius: 50px;
    background: var(--glass); backdrop-filter: blur(10px);
    color: var(--neon-cyan); font-family: var(--font-heading);
    font-size: 1rem; font-weight: 600; cursor: pointer;
    transition: all 0.3s; opacity: 0; animation: fade-in-up 0.6s 2s forwards;
}
.next-btn:hover, .next-btn:active {
    background: var(--neon-cyan); color: var(--bg-primary);
    box-shadow: 0 0 25px rgba(0,229,255,0.4);
}

/* ========= STAGE 4 – MUSIC ========= */
#stage-4 { background: linear-gradient(160deg, #0f0225 0%, #1a0040 50%, #0a0015 100%); }
.music-layout {
    max-width: 700px; padding: 24px 16px; gap: 20px;
    overflow-y: auto; max-height: 100vh;
    justify-content: flex-start; padding-top: 40px;
}
.music-header { text-align: center; margin-bottom: 8px; }
.section-title {
    font-family: var(--font-heading); font-size: clamp(1.3rem, 5vw, 1.8rem);
    font-weight: 800; color: var(--neon-cyan);
    text-shadow: 0 0 20px rgba(0,229,255,0.4);
}
.section-sub { font-size: 0.9rem; color: var(--soft-white); margin-top: 4px; opacity: 0.8; }
.music-cards { display: flex; flex-direction: column; gap: 20px; width: 100%; }
.song-card {
    display: flex; align-items: center; gap: 20px; padding: 20px;
    background: var(--glass); border: 1px solid var(--glass-border);
    border-radius: 20px; backdrop-filter: blur(16px);
    transition: border-color 0.3s, box-shadow 0.3s;
}
.song-card.playing {
    border-color: var(--neon-pink);
    box-shadow: 0 0 30px rgba(255,45,149,0.15);
}
.vinyl-wrapper { flex-shrink: 0; width: 100px; height: 100px; }
.vinyl {
    width: 100%; height: 100%; border-radius: 50%;
    background: radial-gradient(circle, #222 0%, #111 30%, #1a1a1a 32%,
        #111 34%, #1a1a1a 60%, #111 62%, #1a1a1a 80%, #222 100%);
    position: relative; box-shadow: 0 4px 20px rgba(0,0,0,0.5);
    transition: box-shadow 0.3s;
}
.vinyl.spinning {
    animation: vinyl-spin 3s linear infinite;
    box-shadow: 0 0 30px rgba(255,45,149,0.3);
}
.vinyl-shine {
    position: absolute; inset: 0; border-radius: 50%;
    background: linear-gradient(135deg, transparent 30%, rgba(255,255,255,0.05) 45%, transparent 60%);
}
.vinyl-grooves {
    position: absolute; inset: 8px; border-radius: 50%;
    border: 1px solid rgba(255,255,255,0.05);
    box-shadow: inset 0 0 0 6px rgba(255,255,255,0.02), inset 0 0 0 12px rgba(255,255,255,0.03),
        inset 0 0 0 18px rgba(255,255,255,0.02), inset 0 0 0 24px rgba(255,255,255,0.03);
}
.vinyl-label {
    position: absolute; width: 36px; height: 36px;
    top: 50%; left: 50%; transform: translate(-50%, -50%);
    border-radius: 50%;
    background: linear-gradient(135deg, var(--neon-pink), var(--neon-purple));
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    box-shadow: 0 0 10px rgba(255,45,149,0.5);
}
.label-title { font-size: 0.35rem; font-weight: 700; color: var(--white); line-height: 1; }
.label-artist { font-size: 0.25rem; color: rgba(255,255,255,0.7); line-height: 1; margin-top: 1px; }
.song-info { flex: 1; min-width: 0; }
.song-name { font-family: var(--font-heading); font-size: 1.2rem; font-weight: 700; margin-bottom: 2px; }
.song-feat { font-size: 0.75rem; color: var(--neon-pink); opacity: 0.7; margin-bottom: 10px; }
.player-controls { display: flex; align-items: center; gap: 10px; }
.play-btn {
    width: 40px; height: 40px; border: 2px solid var(--neon-pink);
    border-radius: 50%; background: transparent; color: var(--neon-pink);
    font-size: 0.9rem; cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: all 0.3s; flex-shrink: 0;
}
.play-btn:hover, .play-btn:active { background: var(--neon-pink); color: var(--white); }
.play-btn.active { background: var(--neon-pink); color: var(--white); box-shadow: 0 0 15px rgba(255,45,149,0.5); }
.progress-wrap { flex: 1; display: flex; align-items: center; gap: 8px; }
.progress-bar {
    flex: 1; height: 4px; background: rgba(255,255,255,0.15);
    border-radius: 2px; cursor: pointer; position: relative; overflow: hidden;
}
.progress-fill {
    height: 100%; width: 0%;
    background: linear-gradient(90deg, var(--neon-pink), var(--neon-cyan));
    border-radius: 2px; transition: width 0.1s linear;
}
.time-display {
    font-size: 0.75rem; color: var(--soft-white);
    font-variant-numeric: tabular-nums; min-width: 32px; text-align: right;
}
.visualizer { display: flex; align-items: flex-end; gap: 3px; height: 24px; margin-top: 10px; }
.viz-bar { width: 4px; height: 4px; background: var(--neon-pink); border-radius: 2px; }
.visualizer.active .viz-bar { animation: viz-bounce 0.6s ease-in-out infinite alternate; }
.viz-bar:nth-child(1)  { animation-delay: 0.00s; --h: 0.7; }
.viz-bar:nth-child(2)  { animation-delay: 0.05s; --h: 0.4; }
.viz-bar:nth-child(3)  { animation-delay: 0.10s; --h: 0.9; }
.viz-bar:nth-child(4)  { animation-delay: 0.15s; --h: 0.5; }
.viz-bar:nth-child(5)  { animation-delay: 0.20s; --h: 1.0; }
.viz-bar:nth-child(6)  { animation-delay: 0.25s; --h: 0.3; }
.viz-bar:nth-child(7)  { animation-delay: 0.30s; --h: 0.8; }
.viz-bar:nth-child(8)  { animation-delay: 0.35s; --h: 0.6; }
.viz-bar:nth-child(9)  { animation-delay: 0.40s; --h: 0.9; }
.viz-bar:nth-child(10) { animation-delay: 0.45s; --h: 0.4; }
.viz-bar:nth-child(11) { animation-delay: 0.50s; --h: 0.7; }
.viz-bar:nth-child(12) { animation-delay: 0.55s; --h: 0.5; }