Chuletas CSS

chuletas.css

/*centrar imagenes en un div de bootstrap*/
style="display : block ; margin : 0 auto ;"

/*footer siempre en la parte de abajo*/
 <footer style ="position:absolute;bottom:0">

/* Intrinsic HTML Elements */
body{margin:0;padding:0;}
div{margin:0;padding:0;}
h1, h2, h3, p{margin:0;padding:10px;}
ul{margin:0;padding:0;}
li{list-style-type:none;padding:10px;}
 
/* Uniquely Identified Containers */
#page_container{width:760px;margin:0 auto;}
#header{background:#999;}
#left_column{width:180px;float:left;background:#CCC;}
#center_column{width:400px;float:left;background:#ECECEC;}
#right_column{width:180px;float:left;background:#CCC;
#footer{clear:both;background:#999;}

/*todo lo de la tabla arriba*/
valign="top"

/*Buen ejemplo de como hacer divs centrados
http://blog.themeforest.net/tutorials/vertical-centering-with-css */

/*boton bonito*/
<style>
        .btn
        {
            background: #3498db ;
            background-image: -webkit-linear-gradient(top, #3498db, #2980b9) ;
            background-image: -moz-linear-gradient(top, #3498db, #2980b9) ;
            background-image: -ms-linear-gradient(top, #3498db, #2980b9) ;
            background-image: -o-linear-gradient(top, #3498db, #2980b9) ;
            background-image: linear-gradient(to bottom, #3498db, #2980b9) ;
            -webkit-border-radius: 28 ;
            -moz-border-radius: 28 ;
            border-radius: 28px ;
            font-family: Arial ;
            color: #ffffff;
            font-size: 20px;
            padding: 10px 20px 10px 20px;
            text-decoration: none ;
        }

            .btn:hover
            {
                background: #3cb0fd ;
                background-image: -webkit-linear-gradient(top, #3cb0fd, #3498db) ;
                background-image: -moz-linear-gradient(top, #3cb0fd, #3498db) ;
                background-image: -ms-linear-gradient(top, #3cb0fd, #3498db) ;
                background-image: -o-linear-gradient(top, #3cb0fd, #3498db) ;
                background-image: linear-gradient(to bottom, #3cb0fd, #3498db) ;
                text-decoration: none ;
            }
    </style >