body {
    background-color: #AAA;
    padding: 1%;
}

.container {
    width: 100%;
    height: 100%;
}

    .container .banner {
        position: absolute;
        background-color: #f2f2f2;
        width: calc(100% - 1px);
        height: calc(100% - 1px);
        top: 0;
        left: 0;
        z-index: 10;
        display: flex;
        justify-content: center;
        align-items: center;
        container-type: inline-size;
    }

        .container .banner .layer {
            width: calc(90% - 50px);
        }

    .container .chatbot {
        padding: 1px;
    }

        .container .chatbot iframe {
            width: 100%;
            height: 100%;
            border: 1px solid #333333;
        }