.main{
        background-image: url(https://smu-nicuresearch.com/wp-content/uploads/2022/09/pc背景_220915.jpg);
    }

.main main {
    background: url(https://smu-nicuresearch.com/wp-content/uploads/2025/03/PCタイトル_250324.png) center top no-repeat;
}

.container{
        background: #dec5e8;
    }

@media screen and (max-width: 768px) {
    .main{
        background-image: url(https://smu-nicuresearch.com/wp-content/uploads/2022/09/sp背景_220915.jpg);
    }

.main main {
    background: url(https://smu-nicuresearch.com/wp-content/uploads/2025/03/SPタイトル_250324.png) center top no-repeat;
}

.container{
        background: #dec5e8;
    }

}