body{
    font-family: "Microsoft YaHei", sans-serif;
}

.container{
    position: fixed;

    width: 100%;
    height: 100%;

    left: 0;
    top: 0;

    display: flex;
    align-items: center;
    justify-content: center;


}

.main{
    width: 80%;
    height: 70%;

    display: flex;
    flex-flow: row nowrap;
    
    color: #aaa;
    background-color: white;

}

.displayer{
    flex: 1;
    height: 100%;

    box-sizing: border-box;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    -ms-box-sizing: border-box;
    
    padding: 16px;

    display: flex;
    align-items: center;
    justify-content: center;

}

.displayer img{
    max-height: 100%;
    max-width: 100%;
}

.holder{
    flex: 1;
    height: 100%;

    border: 2px #aaa dashed;
    border-radius: 4px;

    display: flex;
    align-items: center;
    justify-content: center;

    box-sizing: border-box;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    -ms-box-sizing: border-box;
    
    padding: 16px;

    background-color: white;

    transition: background-color 0.4s;
}

.holder h1{
    text-align: center;
    user-select: none;
    -moz-user-select: none;
    -webkit-user-select: none;
    -ms-user-select: none;
}