:root {
    --bg-color: #0b0c10;
    --surface-color: #1a1c24;
    --accent-color: #818cf8;
    --accent-glow: rgba(129, 140, 248, 0.4);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --danger: #ef4444;
    --panel-bg: rgba(20, 21, 25, 0.92);
    --glass-border: rgba(255, 255, 255, 0.08);
    --control-bar-height: 80px;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

body {
    margin: 0; padding: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
    display: flex; justify-content: center;
}

/* --- Dynamic Background Layer --- */
#bg-layer {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    z-index: 0;
    transition: opacity 1.5s ease;
    background: #0b0c10; /* fallback */
    overflow: hidden;
}

/* Background States */
#bg-layer.bg-deep-focus {
    background: radial-gradient(circle at 50% 120%, #312e81 0%, #0f172a 60%, #000000 100%);
}
#bg-layer.bg-ocean_flow {
    background: linear-gradient(180deg, #0f172a 0%, #1e293b 50%, #0c4a6e 100%);
    animation: ocean-pulse 10s infinite alternate;
}
@keyframes ocean-pulse { 0% { opacity: 0.8; } 100% { opacity: 1; } }

#bg-layer.bg-stormy_cabin {
    background: linear-gradient(to bottom, #18181b, #27272a);
}

#bg-layer.bg-zen_garden {
    background: radial-gradient(circle at 50% 50%, #14532d 0%, #022c22 70%);
}
#bg-layer.bg-beta_boost {
    background: linear-gradient(135deg, #312e81 0%, #4c1d95 100%);
    background-size: 200% 200%;
    animation: gradient-flow 8s ease infinite;
}
@keyframes gradient-flow { 0% {background-position:0% 50%} 50% {background-position:100% 50%} 100% {background-position:0% 50%} }


/* --- Layout Principal --- */
.app-container {
    width: 100%; max-width: 1200px; height: 100%;
    display: flex; flex-direction: column;
    align-items: center; justify-content: space-between;
    padding: 20px 20px var(--control-bar-height) 20px;
    position: relative; z-index: 2;
}

/* --- Center Content (Timer + Visualizer) --- */
.center-stage {
    flex: 1;
    display: flex; flex-direction: column;
    align-items: center; justify-content: center;
    width: 100%;
    margin-top: -40px; /* Visual balance */
}

/* Visualizer */
.visualizer-container {
    position: relative;
    width: 200px; height: 200px;
    display: flex; align-items: center; justify-content: center;
    margin-bottom: 30px;
}
.visualizer-circle {
    width: 100%; height: 100%; border-radius: 50%;
    background: radial-gradient(circle, rgba(129,140,248,0.15) 0%, transparent 70%);
    box-shadow: 0 0 60px var(--accent-glow), inset 0 0 30px rgba(129,140,248,0.1);
    transition: transform 0.2s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}
.visualizer-circle.active {
    animation: breathe 6s infinite ease-in-out;
}
@keyframes breathe {
    0%, 100% { transform: scale(1); opacity: 0.8; }
    50% { transform: scale(1.08); opacity: 1; }
}

/* Timer */
.timer-display { 
    font-size: 5rem; font-weight: 200; 
    font-variant-numeric: tabular-nums; 
    letter-spacing: -2px;
    line-height: 1; 
    text-shadow: 0 4px 30px rgba(0,0,0,0.3);
}
.timer-status { 
    font-size: 0.85rem; text-transform: uppercase; letter-spacing: 4px; 
    color: var(--accent-color); margin-top: 10px; opacity: 0.9; font-weight: 500;
}

/* --- Bottom Control Bar --- */
.control-bar {
    position: fixed; bottom: 25px; 
    display: flex; align-items: center; gap: 20px;
    padding: 10px 25px;
    background: rgba(255, 255, 255, 0.03);
    backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 50px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.4);
    z-index: 50;
}

/* Control Buttons */
.btn-control {
    background: transparent; border: none; color: var(--text-secondary);
    width: 44px; height: 44px; border-radius: 50%;
    font-size: 1.2rem; cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: all 0.2s ease;
}
.btn-control:hover { color: #fff; background: rgba(255,255,255,0.1); }
.btn-control.active { color: var(--accent-color); background: rgba(129, 140, 248, 0.15); }

/* Play Button Highlight */
.btn-play {
    width: 60px; height: 60px; font-size: 1.5rem;
    background: var(--text-primary); color: var(--bg-color);
    box-shadow: 0 0 20px rgba(255,255,255,0.3);
}
.btn-play:hover { transform: scale(1.05); background: #fff; color: #000; }
.btn-play.running { background: var(--accent-color); color: white; box-shadow: 0 0 20px var(--accent-glow); }


/* --- POPUPS / MODALS --- */
.popup-menu {
    position: absolute; bottom: 90px;
    background: var(--panel-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(20px);
    border-radius: 16px; padding: 10px;
    width: 260px;
    opacity: 0; pointer-events: none; transform: translateY(10px) scale(0.95);
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    display: flex; flex-direction: column; gap: 5px;
}
.popup-menu.show { opacity: 1; pointer-events: auto; transform: translateY(0) scale(1); }

/* Profile List */
.profile-option {
    background: transparent; border: none; color: var(--text-secondary);
    padding: 12px 16px; width: 100%; text-align: left;
    cursor: pointer; border-radius: 8px; font-size: 0.9rem;
    transition: background 0.2s; font-family: inherit;
    display: flex; justify-content: space-between; align-items: center;
}
.profile-option:hover { background: rgba(255,255,255,0.05); color: #fff; }
.profile-option.selected { background: rgba(129, 140, 248, 0.15); color: var(--accent-color); font-weight: 500; }
.profile-option.selected::after { content: '●'; font-size: 0.8rem; }

/* Volume Popup */
.volume-popup-content {
    padding: 15px; display: flex; align-items: center; gap: 10px;
    height: 60px; width: 200px;
}

/* --- Mixer Panel (Bottom Sheet) --- */
.mixer-panel {
    position: fixed; bottom: 0; left: 50%; 
    width: 100%; max-width: 500px; /* FIXED WIDTH */
    background: var(--panel-bg); 
    backdrop-filter: blur(30px);
    border-radius: 24px 24px 0 0; padding: 30px;
    transform: translate(-50%, 110%); /* Center X, Hide Y */
    transition: transform 0.4s cubic-bezier(0.19, 1, 0.22, 1);
    z-index: 60; max-height: 80vh; 
    display: flex; flex-direction: column;
    border-top: 1px solid rgba(255,255,255,0.1);
    box-shadow: 0 -20px 50px rgba(0,0,0,0.6);
}
.mixer-panel.open { transform: translate(-50%, 0); }

.mixer-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 25px; }
.mixer-header h3 { margin: 0; font-weight: 500; font-size: 1.1rem; color: #fff; }
.btn-close { 
    background: rgba(255,255,255,0.05); border: none; 
    width: 32px; height: 32px; border-radius: 50%;
    font-size: 1.2rem; color: var(--text-secondary); cursor: pointer; 
}

.mixer-content { overflow-y: auto; padding-right: 5px; }
.mixer-content::-webkit-scrollbar { width: 4px; }
.mixer-content::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.2); border-radius: 4px; }

.control-group { margin-bottom: 30px; }
.control-group h4 { 
    font-size: 0.7rem; color: var(--accent-color); 
    text-transform: uppercase; margin-bottom: 15px; 
    border-bottom: 1px solid rgba(255,255,255,0.1); 
    padding-bottom: 8px; letter-spacing: 1.5px; font-weight: 600;
}

.slider-row { margin-bottom: 18px; }
.slider-row label { display: flex; justify-content: space-between; font-size: 0.85rem; margin-bottom: 10px; color: #e2e8f0; }
.slider-row label span { font-size: 0.75rem; color: var(--text-secondary); opacity: 0; transition: opacity 0.2s; }
.slider-row:hover label span { opacity: 1; }

input[type=range] { -webkit-appearance: none; width: 100%; background: transparent; }
input[type=range]::-webkit-slider-runnable-track {
    width: 100%; height: 4px; 
    background: rgba(255,255,255,0.1); border-radius: 2px;
    cursor: pointer;
}
input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none; 
    height: 16px; width: 16px; border-radius: 50%;
    background: #fff; 
    cursor: pointer; margin-top: -6px;
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
    transition: transform 0.1s;
}
input[type=range]:hover::-webkit-slider-thumb { transform: scale(1.2); }

/* --- Warning Banner --- */
.warning-banner {
    position: fixed; top: 0; left: 0; width: 100%;
    background: rgba(239, 68, 68, 0.9); color: white; font-size: 0.8rem;
    text-align: center; padding: 10px; font-weight: 500;
    transform: translateY(-100%); transition: transform 0.3s ease-out;
    z-index: 100; backdrop-filter: blur(5px);
}
.warning-banner.active { transform: translateY(0); }
.credits {
    position: fixed;
    bottom: 8px;
    right: 12px;
    font-size: 0.7rem;
    color: rgba(255,255,255,0.35);
    z-index: 10;
    user-select: none;
}

.credits a {
    color: rgba(255,255,255,0.45);
    text-decoration: none;
}

.credits a:hover {
    color: var(--accent-color);
}