:root {
    --primary: #2563eb;
    --success: #16a34a;
    --warning: #ca8a04;
    --danger: #dc2626;
    --dark: #1e293b;
    --light: #f1f5f9;
    --border: #e2e8f0;
    
    /* Colores base para Modo Claro */
    --bg-body: #f8fafc;
    --bg-card: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --bg-table-header: #f1f5f9;
}

/* Colores base para Modo Oscuro */
body.dark-theme {
    --bg-body: #0f172a;
    --bg-card: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border: #334155;
    --light: #1e293b;
    --bg-table-header: #0f172a;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.5;
    transition: background-color 0.2s, color 0.2s;
    padding: 10px;
    position: relative;
    min-height: 100vh;
}

/* 
   EFECTO DE FONDO DUAL (CLARO/OSCURO) CON 20% DE OPACIDAD 
   Se aplica en un pseudo-elemento independiente para evitar que el texto o las tarjetas hereden la transparencia.
*/
body::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
    background-image: url('bg.jpeg'); /* Imagen de fondo definida por el usuario */
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    opacity: 0.2; /* 20% de opacidad para fundirse de forma natural con los temas */
    pointer-events: none; /* Previene interferencias con clics en la pantalla */
}

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 16px;
    position: relative;
    z-index: 1;
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    transition: background-color 0.2s, border-color 0.2s, box-shadow 0.2s;
}

/* Sistema de Grillas Responsivo Corregido */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
    margin-bottom: 20px;
}

.form-group {
    margin-bottom: 16px;
}

label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--text-main);
}

input, select, textarea {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 15px;
    outline: none;
    background-color: var(--bg-body);
    color: var(--text-main);
    transition: border-color 0.2s, background-color 0.2s, color 0.2s;
}

input:focus, select:focus, textarea:focus {
    border-color: var(--primary);
}

input[readonly] {
    background-color: var(--light);
    cursor: not-allowed;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 20px;
    font-size: 15px;
    font-weight: 600;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    width: 100%;
    text-decoration: none;
    transition: background-color 0.2s;
}

.btn-primary { background: var(--primary); color: #fff; }
.btn-success { background: var(--success); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }

/* Estructura de Tablas Responsivas */
.table-wrapper {
    overflow-x: auto;
    width: 100%;
    margin-top: 10px;
    border-radius: 8px;
    border: 1px solid var(--border);
}

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border);
    font-size: 14px;
    color: var(--text-main);
    white-space: nowrap;
}

th {
    background-color: var(--bg-table-header);
    font-weight: 600;
}

.pos-layout {
    display: grid;
    grid-template-columns: 1fr 380px;
    gap: 16px;
}

@media (max-width: 768px) {
    .pos-layout {
        grid-template-columns: 1fr;
    }
}