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

body {
    font-family: Arial, sans-serif;
}

.container {
    border: 1px solid blue;
    padding: 10px;
    width: 800px;
    margin: 20px auto;
    text-align: center;
}

.banner {
    background-color: red;
    color: white;
    font-size: 20px;
    padding: 20px;
    animation: bannerChange 5s infinite alternate;
}

@keyframes bannerChange {
    0% {
        background-color: red;
        font-size: 20px;
    }
    50% {
        background-color: magenta;
        font-size: 40px;
    }
    100% {
        background-color: cyan;
        font-size: 20px;
    }
}

.content {
    margin-top: 20px;
    display: flex;
    justify-content: space-around;
    align-items: center;
}

.box {
    width: 100px;
    height: 100px;
    line-height: 100px;
    font-size: 24px;
    text-align: center;
    margin: 10px;
}

/* Box 1 - hình ảnh thay đổi */
.box1 {
    border: 3px solid red;
    animation: imageChange 6s infinite alternate;
}

@keyframes imageChange {
    0% {
        content: url("img1.jpg");
    }
    100% {
        content: url("img2.jpg");
    }
}

/* Box 2 */
.box2 {
    background-color: cyan;
    border: 3px dashed blue;
    border-radius: 20% 0 0 0;
}

/* Box 3 */
.box3 {
    background-color: cyan;
    border: 2px dotted violet;
    border-radius: 0 20% 0 0;
}

/* Box 4 - hiệu ứng xoay */
.box4 {
    background-color: darkgreen;
    color: yellow;
    transform-origin: center center;
    animation: rotateBox 4s linear infinite;
}

@keyframes rotateBox {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}