body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #ffffff;
}

.main-border {
    border: 1px solid #3b82f6;
    padding: 20px;
    width: 600px;
    background-color: #fff;
}

@keyframes changeBgBanner {
    0% { background-color: #ff007f; }
    33% { background-color: #aa00ff; }
    66% { background-color: #ff0000; }
    100% { background-color: #ff007f; }
}

@keyframes scaleText {
    0% { font-size: 12px; }
    50% { font-size: 20px; }
    100% { font-size: 12px; }
}

.banner-container {
    width: 100%;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    animation: changeBgBanner 6s infinite linear;
}

.banner-text {
    color: #fff;
    font-weight: bold;
    letter-spacing: 2px;
    animation: scaleText 6s infinite linear;
}

.box-container {
    display: flex;
    justify-content: space-between;
    margin-top: 30px;
    padding: 0 10px;
}

.box {
    width: 90px;
    height: 90px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
    font-size: 16px;
    border-radius: 4px;
}

/* Khung 1: Tuần tự thay đổi qua lại giữa 2 ảnh, luôn giữ số 1 ở trên */
@keyframes slideImages {
    0%, 45% {
        background-image: url('../images/6.jpg');
    }
    55%, 100% {
        background-image: url(../images/3.jpg);
    }
}

.box-1 {
    border: 2px solid #e74c3c;
    position: relative;
    background-size: cover;
    background-position: center;
    animation: slideImages 6s infinite ease-in-out;
}

.box-1 .number-one {
    position: relative;
    z-index: 2;
    color: #000; /* Thay đổi màu chữ số 1 tại đây nếu ảnh làm mờ số */
    font-size: 20px;
}

.box-2 {
    background-color: #00ffff;
    color: #008b8b;
    border: 2px dashed #008b8b;
}

.box-3 {
    background-color: #00ffff;
    color: #008b8b;
}

@keyframes rotateClockwise {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.box-4 {
    background-color: #008080;
    color: #adff2f;
    animation: rotateClockwise 4s infinite linear;
}