style.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: #c6bba5;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI";
}

/* Container with the 3 divisions for the card  */
.container{
    display: flex;
    flex-direction: column;
    width: 300px;
    height: 500px;
    margin: 110px auto;
    overflow: hidden;
    border-radius: 17px;
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 6px 6px 20px 0 rgba(0, 0, 0, 0.19);
}

/* A container to hold the image and the card  */
.contUpper {
    overflow: visible;
    box-shadow: none;
    position: relative;
    display: block;
    opacity: 0.9;
    transition: all 0.4s ease-in;
}

.contUpper:hover {
    opacity: 1;
}

/* 3 divs inside the container */
/* First */
.background {
    flex: 1;
    background-image: url('card-bg.jpg');
    background-repeat: no-repeat;
    min-height: 200px;
}
/* Seconde */
.white-background {
    flex: 1;
    background-color: white;
    max-height: 200px;
}
/* Third */
.power-info {
    min-height: 80px;
    display: flex;
    position: relative;
}
    /* customized fotter colors for different fighters */
    
    /* div holding the number and the text of the fighter */
    .center-align {
        flex: 1;
        color: white;
        text-align: center;
    }

    .number {
        font-size: 1.6em;
        padding-top: 7px;
    }

    .stats {
        text-transform: uppercase;
        padding-top: 7px;
        font-size: 0.7em;
    }

    .middle-border {
        border-right: 1px solid black;
        border-left: 1px solid black;
    }

    span {
        display: block;
    }

.level {
    padding-top: 35px;
    color: #EC9B3B;
    font-size: 0.8em;
    text-align: center;
    font-weight: bold;
}

.heroName {
    color: black;
    font-size: 1.8em;
    text-align: center;
    font-weight: bolder;
}

.heroinfo {
    padding: 20px 10px;
    color: #a6a6a6;
    font-size: 0.9em;
    text-align: center;
}

    /* arrows for changing cards */ 
    .left-arrow {
        position: absolute;
        top: 243px;
        right: 370px;    
        opacity: 0.7;
        transition: all 0.2s ease-in;
    }
    .right-arrow {
        position: absolute;
        top: 243px;
        left: 370px;
        opacity: 0.7;
        transition: all 0.2s ease-in;
    }

    .arr-color:visited, .arr-color:active, .arr-color {
        color: #f0ede9;
        
    }

    .arr-color:hover {
        opacity: 1;
    }


/* The cards customization */

/* first card */
/* first card image */ 
.fighter1Img {
    position: absolute;
    bottom: 260px;
    right: -30px;
}
/* footer color */
.fighter1 {
    background-color: #EC9B3B;
}

/* second card */
/* Seconde card image */ 
.fighter2Img {
    position: absolute;
    bottom: 231px;
    right: -25px;
    width: 350px;
}
/* footer color */ 

.fighter2 {
    background-color: #4FACFF;
}
/* third card */ 
/* third card image */ 
.fighter3Img {
    position: absolute;
    bottom: 231px;
    right: -14px;
    width: 350px;
}
/* footer color */ 

.fighter3 {
    background-color: #78ad29;
}

/* Visibility */ 

#firstCard {
    display: block;
    
}

#secondCard { 
    display: none;
}

#thirdCard {
    display: none;
}