body {
    font-family: Arial, sans-serif;
    text-align: center;
    background-color: #f4f4f4;
    margin: 40px;
}

h1 {
    color: #333;
    margin-bottom: 30px;
}

/*------- zonas -------*/
#cajasoltar,
#cajaimagenes {
    float: left;
    width: 420px;
    min-height: 300px;
    margin: 20px;
    padding: 20px;
    border-radius: 10px;
    box-sizing: border-box;
    transition: background-color 0.2s, border-color 0.2s;
    position: relative;
}

#cajasoltar {
    border: 3px dashed #999;
    background: #fafafa;
}

#cajaimagenes {
    border: 3px solid #999;
    background: #ffffff;
}

.texto-vacio {
    color: #bbb;
    font-style: italic;
    font-size: 14px;
    pointer-events: none;
    margin: 0;
    padding-top: 10px;
}

/*------- feedback al arrastrar sobre zona -------*/
.zona-activa {
    border-color: #4a90d9 !important;
    background-color: #e8f3fd !important;
}

/*------- imagen mientras se arrastra -------*/
.arrastrando {
    opacity: 0.4;
    transform: scale(0.95);
}

/*------- animación al soltar -------*/
@keyframes entrada {
    from {
        opacity: 0;
        transform: scale(0.8);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.recien-soltado {
    animation: entrada 0.25s ease-out;
}

/*------- imágenes -------*/
.cajas {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}
#cajasoltar img,
#cajaimagenes img {
    width: 100px;
    margin: 10px;
    cursor: grab;
    border-radius: 8px;
    transition: transform 0.15s, box-shadow 0.15s;
}

#cajasoltar img:hover,
#cajaimagenes img:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

#cajasoltar img:active,
#cajaimagenes img:active {
    cursor: grabbing;
}