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

body {
    background-color: #f5f5f5;
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.wrapper {
    width: 700px;
    background-color: #ffffff;
    border: 1px solid #ccc;
    padding: 20px;
}

.banner {
    width: 100%;
    height: 70px;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #333;
    font-weight: bold;
    margin-bottom: 25px;
    border: 1px solid #dcdcdc;
    animation: bannerEffect 4s infinite alternate ease-in-out;
}

@keyframes bannerEffect {
    0% {
        background-color: #ff5252;
        font-size: 14px;
        color: #ffffff;
    }
    50% {
        background-color: #e040fb;
        font-size: 26px;
        color: #ffffff;
    }
    100% {
        background-color: #448aff;
        font-size: 16px;
        color: #ffffff;
    }
}

.card-grid {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
}

.box {
    width: 120px;
    height: 120px;
}

.box-1 {
    background-size: cover;
    background-position: center;
    border: 1px solid #ccc;
    /* Tự động đổi ảnh nền */
    animation: changeImage 6s infinite steps(1);
}

@keyframes changeImage {
    0% {
        background-image: url('../images/html.jpg');
    }
    33% {
        background-image: url('../images/css.jpg');
    }
    66% {
        background-image: url('../images/javascript.jpg');
    }
}

.box-2 {
    background-color: #4dd0e1;
    border: 2px dashed #00acc1;
    border-radius: 25px 0px 25px 0px;
}

.box-3 {
    background-color: #4dd0e1;
    border-radius: 0px 25px 0px 25px;
}

.box-4 {
    background-color: #2e7d32;
    color: #ffffff;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
    animation: rotateClockwise 5s infinite linear;
}

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