:root {
    --color-fondo: #f4f4f4;
    --color-card: #ffffff;
    --color-texto: #222222;
    --color-primario: #333333;
    --color-borde: #cccccc;
    --color-item: #fafafa;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background: var(--color-fondo);
    color: var(--color-texto);
    font-family: sans-serif;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    background: #ddd;
    border-bottom: 1px solid var(--color-borde);
}

.btn-logout {
    background: #721c24;
    color: var(--color-card);
    border: none;
    padding: 6px 12px;
    cursor: pointer;
}

.main-container {
    padding: 20px;
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.card {
    background: var(--color-card);
    border: 1px solid var(--color-borde);
    padding: 15px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.ventas-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 15px;
    width: 100%;
}

@media (min-width: 768px) {
    .ventas-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (min-width: 1024px) {
    .ventas-grid {
        grid-template-columns: 1fr 1fr 1fr;
    }
}

.item-venta {
    background: var(--color-item);
    border: 1px solid var(--color-borde);
    padding: 10px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    min-width: 0;
}

.btn-vender {
    background: #28a745;
    color: var(--color-card);
    border: none;
    padding: 6px;
    cursor: pointer;
    margin-top: auto;
}

.historial-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
    width: 100%;
}

@media (min-width: 768px) {
    .historial-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (min-width: 1024px) {
    .historial-grid {
        grid-template-columns: 1fr 1fr 1fr;
    }
}

.item-historial {
    display: flex;
    justify-content: space-between;
    padding: 8px;
    background: var(--color-item);
    border: 1px solid var(--color-borde);
    min-width: 0;
}

.mensaje-alerta {
    display: none;
    padding: 8px;
    font-size: 14px;
}

.header-acciones {
    display: flex;
    align-items: center;
    gap: 10px;
}

.link-admin {
    color: #333333;
    text-decoration: none;
    border: 1px solid #999999;
    padding: 5px 10px;
    font-size: 14px;
}

.link-admin:hover {
    background: #cccccc;
}

.historial-derecha {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 6px;
}

.btn-eliminar-venta {
    background: #c82333;
    color: #ffffff;
    border: none;
    padding: 4px 8px;
    font-size: 12px;
    cursor: pointer;
    white-space: nowrap;
}

.btn-eliminar-venta:hover {
    background: #a71d2a;
}