:root {
    --bg-main: #0f172a;
    --bg-card: #1e293b;
    --bg-input: #334155;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --success: #10b981;
    --warning: #f59e0b;
    --warning-hover: #d97706;
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --border: #475569;
    --radius: 12px;
    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', system-ui, sans-serif; }
body { background-color: var(--bg-main); color: var(--text-main); min-height: 100vh; padding-bottom: 40px; }

/* Pantalla Auth */
.auth-wrapper { position: fixed; inset: 0; background: var(--bg-main); display: flex; justify-content: center; align-items: center; z-index: 1000; }
.auth-card { width: 100%; max-width: 400px; padding: 30px; text-align: center; }

/* Header */
.main-header { background-color: rgba(30, 41, 59, 0.7); backdrop-filter: blur(10px); position: sticky; top: 0; z-index: 50; border-bottom: 1px solid var(--border); }
.header-container { max-width: 1400px; margin: 0 auto; padding: 15px 20px; display: flex; justify-content: space-between; align-items: center; }
.header-container h1 span { color: var(--primary); }

/* Layout */
.app-container { max-width: 1400px; margin: 30px auto 0; padding: 0 20px; display: grid; grid-template-columns: 400px 1fr; gap: 30px; }
@media(max-width: 900px) { .app-container { grid-template-columns: 1fr; } }

/* Elementos comunes */
.card { background-color: var(--bg-card); border-radius: var(--radius); padding: 24px; border: 1px solid var(--border); box-shadow: var(--shadow); }
.admin-tabs { display: flex; gap: 10px; margin: 20px 0; background: var(--bg-main); padding: 5px; border-radius: 8px; }
.tab-btn { flex: 1; background: transparent; border: none; color: var(--text-muted); padding: 8px; cursor: pointer; border-radius: 6px; font-weight: 600; }
.tab-btn.active { background: var(--primary); color: #fff; }

.form-group { display: flex; flex-direction: column; gap: 15px; }
.input-row { display: flex; gap: 15px; }
.input-field { display: flex; flex-direction: column; gap: 5px; flex: 1; }
input { background-color: var(--bg-input); border: 1px solid var(--border); color: #fff; padding: 10px 14px; border-radius: 6px; outline: none; }
input:focus { border-color: var(--primary); }

/* Catálogo */
.catalog-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 20px; margin-top: 20px; }
.product-card { background-color: var(--bg-card); border-radius: var(--radius); border: 1px solid var(--border); overflow: hidden; display: flex; flex-direction: column; transition: transform 0.2s; }
.product-card:hover { transform: translateY(-5px); }
.product-img { width: 100%; height: 180px; object-fit: cover; }
.product-info { padding: 15px; display: flex; flex-direction: column; flex-grow: 1; gap: 10px; }
.product-meta { display: flex; justify-content: space-between; align-items: center; }
.price-tag { font-size: 1.25rem; font-weight: 700; color: var(--success); }
.stock-tag { font-size: 0.8rem; padding: 2px 8px; border-radius: 20px; background: var(--bg-input); }
.stock-tag.low { background: rgba(239, 68, 68, 0.2); color: var(--danger); }

/* Botones */
button { font-weight: 600; cursor: pointer; transition: background 0.2s; }
.btn-primary { background: var(--primary); color: #fff; border: none; padding: 12px; border-radius: 6px; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-secondary { background: var(--border); color: #fff; border: none; padding: 12px; border-radius: 6px; }
.btn-warning { background: var(--warning); color: #fff; border: none; }
.btn-warning:hover { background: var(--warning-hover); }
.btn-danger { background: var(--danger); color: white; border: none; }
.btn-danger:hover { background: var(--danger-hover); }
.btn-cart { background: var(--primary); color: #fff; border: none; padding: 10px 20px; border-radius: 20px; }
.btn-action-sm { padding: 8px 12px; border-radius: 6px; font-size: 0.85rem; }
.product-actions { display: flex; gap: 8px; margin-top: auto; }

/* Sidebar Carrito */
.cart-sidebar { position: fixed; top: 0; right: -420px; width: 400px; height: 100vh; background: var(--bg-card); border-left: 1px solid var(--border); box-shadow: -10px 0 30px rgba(0,0,0,0.5); z-index: 100; display: flex; flex-direction: column; transition: right 0.3s; }
.cart-sidebar.open { right: 0; }
.cart-header { padding: 20px; border-bottom: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; }
.btn-close { background: transparent; border: none; font-size: 1.8rem; color: var(--text-muted); }
.cart-items-container { flex-grow: 1; overflow-y: auto; padding: 20px; display: flex; flex-direction: column; gap: 15px; }
.cart-item { display: flex; justify-content: space-between; align-items: center; background: var(--bg-main); padding: 10px; border-radius: 8px; }
.cart-footer { padding: 20px; border-top: 1px solid var(--border); background: var(--bg-main); }
.cart-total-row { display: flex; justify-content: space-between; font-size: 1.2rem; font-weight: 700; margin-bottom: 15px; }
.btn-checkout { width: 100%; background: var(--success); color: white; border: none; padding: 14px; border-radius: 8px; }
.cart-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.6); opacity: 0; pointer-events: none; z-index: 90; transition: opacity 0.3s; }
.cart-overlay.show { opacity: 1; pointer-events: auto; }

/* Historial */
.history-container { display: flex; flex-direction: column; gap: 10px; max-height: 440px; overflow-y: auto; }
.history-item { background: var(--bg-main); padding: 12px; border-radius: 8px; border-left: 4px solid var(--primary); margin-bottom: 10px; cursor: pointer; }
.hidden { display: none !important; }
.empty-msg { text-align: center; color: var(--text-muted); padding: 20px 0; }

/* Modales */
.modal { position: fixed; inset: 0; background: rgba(0,0,0,0.8); z-index: 200; display: flex; justify-content: center; align-items: center; opacity: 0; pointer-events: none; transition: opacity 0.2s; }
.modal.open { opacity: 1; pointer-events: auto; }
.modal-content { background: #fff; color: #000; width: 90%; max-width: 550px; border-radius: 12px; padding: 30px; }
.invoice-box { font-family: 'Courier New', Courier, monospace; }
.invoice-header { display: flex; justify-content: space-between; margin-bottom: 20px; }
.invoice-table { width: 100%; border-collapse: collapse; margin: 20px 0; }
.invoice-table th { background: #f1f5f9; text-align: left; padding: 8px; }
.invoice-table td { padding: 8px; border-bottom: 1px solid #e2e8f0; }
.text-right { text-align: right; }
.text-center { text-align: center; }
.invoice-total-section { text-align: right; font-size: 1.2rem; margin-top: 20px; }
.modal-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 25px; }
.animate-pop { transform: scale(0.9); transition: transform 0.2s; }
.modal.open .animate-pop { transform: scale(1); }

/* Barra de herramientas del catálogo (búsqueda y orden) */
.catalog-toolbar { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 15px; margin-bottom: 10px; }
.toolbar-controls { display: flex; gap: 10px; flex-wrap: wrap; }
.search-input, .sort-select { background-color: var(--bg-card); border: 1px solid var(--border); color: var(--text-main); padding: 10px 14px; border-radius: 6px; outline: none; }
.search-input { min-width: 220px; }
.search-input:focus, .sort-select:focus { border-color: var(--primary); }

/* Vista previa de imagen en el formulario admin */
.image-preview { width: 100%; height: 120px; object-fit: cover; border-radius: 6px; border: 1px solid var(--border); margin-top: 6px; }

/* Pie de página */
.site-footer { text-align: center; padding: 30px 20px 10px; color: var(--text-muted); font-size: 0.85rem; }

/* Notificaciones tipo Toast (reemplazan a alert()) */
.toast-container { position: fixed; bottom: 20px; right: 20px; z-index: 999; display: flex; flex-direction: column; gap: 10px; }
.toast { min-width: 240px; max-width: 320px; background: var(--bg-card); border: 1px solid var(--border); border-left: 4px solid var(--primary); color: var(--text-main); padding: 12px 16px; border-radius: 8px; box-shadow: var(--shadow); opacity: 0; transform: translateX(30px); transition: all 0.3s ease; font-size: 0.9rem; }
.toast.show { opacity: 1; transform: translateX(0); }
.toast-success { border-left-color: var(--success); }
.toast-warning { border-left-color: var(--warning); }
.toast-error { border-left-color: var(--danger); }
.toast-info { border-left-color: var(--primary); }

/* Ventanas modales de alerta/confirmación (reemplazan a alert() y confirm()) */
.modal-dialog-overlay {
    position: fixed; inset: 0; background: rgba(5, 10, 20, 0.75); backdrop-filter: blur(4px);
    display: flex; align-items: center; justify-content: center; z-index: 1100;
    opacity: 0; pointer-events: none; transition: opacity 0.25s ease;
}
.modal-dialog-overlay.show { opacity: 1; pointer-events: auto; }

.modal-dialog-box {
    width: 90%; max-width: 400px; border-radius: 16px; padding: 30px 26px 24px;
    color: #fff; text-align: center; transform: scale(0.9) translateY(10px);
    transition: transform 0.25s ease; box-shadow: 0 20px 45px rgba(0,0,0,0.5);
    border: 1px solid rgba(255,255,255,0.08);
}
.modal-dialog-overlay.show .modal-dialog-box { transform: scale(1) translateY(0); }

.modal-dialog-box.type-info    { background: linear-gradient(150deg, #1e293b 0%, #1d4ed8 60%, #3b82f6 140%); }
.modal-dialog-box.type-success { background: linear-gradient(150deg, #1e293b 0%, #047857 60%, #10b981 140%); }
.modal-dialog-box.type-warning { background: linear-gradient(150deg, #1e293b 0%, #b45309 60%, #f59e0b 140%); }
.modal-dialog-box.type-error   { background: linear-gradient(150deg, #1e293b 0%, #991b1b 60%, #ef4444 140%); }

.modal-dialog-icon { font-size: 2.6rem; line-height: 1; margin-bottom: 12px; filter: drop-shadow(0 2px 6px rgba(0,0,0,0.3)); }
.modal-dialog-title { font-size: 1.25rem; font-weight: 800; margin-bottom: 8px; }
.modal-dialog-message { font-size: 0.92rem; color: rgba(255,255,255,0.88); line-height: 1.55; }
.modal-dialog-actions { display: flex; gap: 10px; margin-top: 24px; }
.modal-dialog-actions button { flex: 1; padding: 12px; border-radius: 8px; border: none; font-weight: 700; cursor: pointer; font-size: 0.9rem; transition: transform 0.15s ease, background 0.15s ease; }
.modal-dialog-actions button:hover { transform: translateY(-1px); }
.btn-modal-confirm { background: #fff; color: #0f172a; }
.btn-modal-confirm:hover { background: #e2e8f0; }
.btn-modal-cancel { background: rgba(255,255,255,0.15); color: #fff; }
.btn-modal-cancel:hover { background: rgba(255,255,255,0.25); }

@media print {
    body * { visibility: hidden; }
    #invoice-print-area, #invoice-print-area * { visibility: visible; }
    #invoice-print-area { position: absolute; left: 0; top: 0; width: 100%; }
}