:root {
    --bg-main: #060202;
    --border-color: #4a1212;
    --accent-red: #ff3333;
    --accent-darkred: #990000;
    --text-main: #f5e6e6;
    --text-muted: #a48a8a;
    --danger: #ff1a1a;
    
    /* Gradientes para los módulos */
    --grad-osc: linear-gradient(135deg, #150505 0%, #2a0808 100%);
    --grad-filter: linear-gradient(135deg, #1a0606 0%, #350a0a 100%);
    --grad-adsr: linear-gradient(135deg, #18050c 0%, #300814 100%);
    --grad-lfo: linear-gradient(135deg, #12081a 0%, #251035 100%);
    --grad-fx: linear-gradient(135deg, #1f0505 0%, #3d0b0b 100%);
    --grad-vis: linear-gradient(135deg, #0d0303 0%, #1c0606 100%);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    user-select: none;
}

body {
    background-color: var(--bg-main);
    color: var(--text-main);
    overflow-x: hidden;
    min-height: 100vh;
}

/* PANTALLA DE AUTENTICACIÓN */
.auth-overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background-color: var(--bg-main);
    display: flex; justify-content: center; align-items: center;
    z-index: 9999;
}

.auth-card {
    background: var(--grad-osc);
    border: 2px solid var(--border-color);
    padding: 2.5rem; border-radius: 12px;
    width: 100%; max-width: 420px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.9);
    text-align: center;
}

.auth-card h2 {
    color: var(--accent-red);
    font-size: 2rem; margin-bottom: 0.5rem;
    text-transform: uppercase; letter-spacing: 2px;
}

.form-group { text-align: left; margin-bottom: 1.2rem; }
.form-group label { display: block; font-size: 0.8rem; margin-bottom: 0.4rem; text-transform: uppercase; }
.form-group input {
    width: 100%; padding: 0.8rem;
    background-color: rgba(0, 0, 0, 0.4); border: 1px solid var(--border-color);
    border-radius: 6px; color: #fff; font-size: 1rem;
}
.form-group input:focus { outline: none; border-color: var(--accent-red); }

#auth-submit-btn {
    width: 100%; padding: 0.9rem;
    background: linear-gradient(135deg, var(--accent-darkred), var(--accent-red));
    border: none; color: white; font-weight: bold; border-radius: 6px;
    text-transform: uppercase; cursor: pointer;
}

/* ESTRUCTURA MAESTRA */
.synth-wrapper {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    padding: 15px;
    gap: 12px;
}
.synth-wrapper.disabled { display: none !important; }

.synth-header {
    background: linear-gradient(90deg, #150505 0%, #220808 100%);
    border: 1px solid var(--border-color);
    padding: 12px 24px; border-radius: 8px;
    display: flex; justify-content: space-between; align-items: center;
}
.synth-header .logo span { color: var(--accent-red); font-weight: bold; }
.global-controls { display: flex; align-items: center; gap: 20px; }

/* REPARACIÓN Y REDISEÑO DE SLIDERS */
input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    background: transparent;
    margin: 6px 0;
}
input[type="range"]:focus { outline: none; }

input[type="range"]::-webkit-slider-runnable-track {
    width: 100%; height: 5px; cursor: pointer;
    background: rgba(0, 0, 0, 0.6); border-radius: 3px;
    border: 1px solid rgba(74, 18, 18, 0.5);
}
input[type="range"]::-moz-range-track {
    width: 100%; height: 5px; cursor: pointer;
    background: rgba(0, 0, 0, 0.6); border-radius: 3px;
    border: 1px solid rgba(74, 18, 18, 0.5);
}

input[type="range"]::-webkit-slider-thumb {
    height: 14px; width: 14px; border-radius: 50%;
    background: var(--accent-red); cursor: pointer;
    -webkit-appearance: none; margin-top: -4.5px;
    box-shadow: 0 0 8px var(--accent-red);
}
input[type="range"]::-moz-range-thumb {
    height: 14px; width: 14px; border-radius: 50%;
    background: var(--accent-red); cursor: pointer;
    border: none; box-shadow: 0 0 8px var(--accent-red);
}

select {
    background-color: rgba(0, 0, 0, 0.5); color: #fff;
    border: 1px solid var(--border-color); padding: 5px;
    border-radius: 4px; font-size: 0.75rem; width: 100%;
}

/* REJILLA DE BLOQUES HORIZONTALES POR FILAS PARTICIONADAS */
.synth-grid {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

/* NUEVO: Contenedores dobles para compartir el ancho de la pantalla */
.synth-row-split {
    display: flex;
    gap: 12px;
    width: 100%;
}
.synth-row-split .module-box {
    flex: 1; /* Hace que compartan el 50% cada uno exactamente */
    min-width: 0; /* Previene desbordamiento en flexbox */
}

/* Estilos de Cajas Modulares */
.module-box {
    border: 1px solid var(--border-color);
    border-radius: 8px; padding: 15px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.4);
}

#mod-oscillators { background: var(--grad-osc); }
#mod-filters { background: var(--grad-filter); }
#mod-noise { background: var(--grad-filter); } /* Mismo gradiente que filtros para consistencia */
#mod-adsr { background: var(--grad-adsr); }
#mod-global-proc { background: var(--grad-adsr); } /* Mismo gradiente que ADSR ya que van en par */
#mod-lfo { background: var(--grad-lfo); }
#mod-effects { background: var(--grad-fx); }
#mod-visualizer { background: var(--grad-vis); }

.module-box h3 {
    font-size: 0.85rem; text-transform: uppercase; color: var(--accent-red);
    margin-bottom: 12px; border-bottom: 1px solid rgba(255, 51, 51, 0.2);
    padding-bottom: 5px; letter-spacing: 1.5px;
}

/* Distribuciones Internas */
.control-row {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    width: 100%;
    align-items: center;
}

.control-item {
    flex: 1;
    min-width: 100px;
    display: flex; 
    flex-direction: column; 
    align-items: center; 
    font-size: 0.75rem; 
    gap: 4px;
}
.control-item label { color: var(--text-muted); text-transform: uppercase; font-size: 0.65rem; font-weight: 600; }
.val-display { color: var(--accent-red); font-family: monospace; font-size: 0.75rem; }

/* Osciladores horizontales */
.oscillators-row { display: flex; flex-direction: row; gap: 12px; width: 100%; }
.osc-card { flex: 1; background-color: rgba(0, 0, 0, 0.3); border: 1px solid rgba(7a, 18, 18, 0.4); border-radius: 6px; padding: 10px; }
.osc-card h4 { font-size: 0.8rem; margin-bottom: 8px; color: var(--accent-red); text-transform: uppercase; border-bottom: 1px solid rgba(255,255,255,0.05); padding-bottom: 2px;}

/* Filtros y Efectos */
.filters-container, .effects-grid { display: flex; flex-direction: row; gap: 12px; width: 100%; }
.filter-block, .fx-block { flex: 1; background-color: rgba(0, 0, 0, 0.3); padding: 10px; border-radius: 6px; border: 1px solid rgba(7a, 18, 18, 0.4); }
.filter-block h4, .fx-block h4 { font-size: 0.75rem; margin-bottom: 6px; color: var(--text-main); text-transform: uppercase;}

/* CORRECCIÓN RADICAL DEL ANALIZADOR DE ESPECTRO */
.visualizer-container { 
    display: flex; 
    flex-direction: column; 
    gap: 10px; 
    width: 100%; 
}
#audio-visualizer { 
    width: 100%; 
    height: 110px; /* Altura física fija garantizada para que las matemáticas del canvas no den cero */
    background-color: rgba(0, 0, 0, 0.6); 
    border-radius: 6px; 
    border: 1px solid var(--border-color); 
    display: block;
}
.vu-meter-container { width: 100%; height: 10px; background-color: rgba(0, 0, 0, 0.5); border-radius: 4px; overflow: hidden; border: 1px solid var(--border-color); }
.vu-bar { height: 100%; width: 0%; background: linear-gradient(90deg, var(--accent-darkred) 70%, var(--accent-red) 100%); }

/* PIANO CENTRALIZADO AL 50% */
.synth-footer {
    display: flex;
    justify-content: center;
    width: 100%;
    margin-top: 5px;
}

.keyboard-container { 
    width: 50%;
    height: 95px; 
    display: flex; 
    position: relative;
    background-color: #110404;
    padding: 4px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    box-shadow: 0 6px 20px rgba(0,0,0,0.6);
}

.key {
    flex: 1; background-color: #e6ddff; border: 1px solid #1a0808;
    border-radius: 0 0 4px 4px; cursor: pointer; position: relative; z-index: 1;
    display: flex; align-items: flex-end; justify-content: center;
    padding-bottom: 6px; color: #2b1f1f; font-size: 0.7rem; font-weight: bold;
    box-shadow: inset 0 -3px 0 #b3a9cc, 0 2px 3px rgba(0,0,0,0.2);
}
.key.white:hover { background-color: #fff; }

.key.black {
    background-color: #1e0909; color: #a48a8a; max-width: 24px; height: 55%;
    margin-left: -12px; margin-right: -12px; z-index: 2;
    border-radius: 0 0 3px 3px;
    box-shadow: inset 0 -2px 0 #000, 0 3px 4px rgba(0,0,0,0.4);
}
.key.black:hover { background-color: #311111; }

.key.active { 
    background-color: var(--accent-red) !important; 
    color: #fff !important; 
    box-shadow: inset 0 2px 8px rgba(0,0,0,0.7), 0 0 8px var(--accent-red) !important; 
}

.btn-danger { background-color: var(--danger); color: white; border: none; padding: 6px 14px; border-radius: 4px; font-weight: bold; cursor: pointer; text-transform: uppercase; font-size: 0.75rem; }
.btn-secondary { background-color: var(--bg-input); color: var(--text-main); border: 1px solid var(--border-color); padding: 6px 14px; border-radius: 4px; cursor: pointer; text-transform: uppercase; font-size: 0.75rem; }

@media (max-width: 1000px) {
    .keyboard-container { width: 75%; }
    .synth-row-split { flex-direction: column; }
    .oscillators-row, .filters-container, .effects-grid { flex-direction: column; }
}
@media (max-width: 650px) {
    .keyboard-container { width: 100%; }
    .synth-header { flex-direction: column; gap: 10px; }
}