Thành viên:Đức Anh/Nháp 79

    Tủ sách mở Wikibooks
    .main-box {
        position: relative;
        margin: 1.2rem auto;
        padding: 1rem 2rem;
        width: 75%;
    	font-family: sans-serif;
    	font-size:125%;
        box-shadow: 0 2px 5px #c5c5c5;
    }
    /*Làm màu*/
    
    .main-box.-red {
    	background-color: #912a16;
    	color:#ffffff;
    }
    .main-box.-cyan {
    	background-color: #2db1b5;	
    	color:#ffffff;
    }
    
    .main-box.-green {
    	background-color: #107d28;
    	color:#ffffff;
    }
    
    .main-box.-yellow {
    	background-color:#e6db8c;
    	color:#000000;
    }
    
    /*Hết làm màu*/
    .main-box::before {
        content: "";
        z-index: -1;
        position: absolute;
        top: 0;
        right: 0;
        width: 100%;
        height: 100%;
        background-image: url(https://upload.wikimedia.org/wikipedia/commons/3/3b/SteacieLibrary.jpg);
        background-size: cover;
        background-repeat: no-repeat;
    }
    
    .main-box *::selection {
        background: rgba(236,236,236,0.35);
    }
    
    .main-box a {
        color: #ffff76;
    }
    
    .main-box a:active,
    .main-box a:focus {
        background-color: rgba(255,207,98,0.5);
        color: #fff;
    }