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

html {
    text-align: center;
    background-color: #ececeb;
    font-family: "Varela Round", sans-serif;
}

h1 {
    font-size: 60px;
}

.page-title {
    margin: 40px;
}

footer {
    margin-top: 20px;
}

a {
    text-decoration: none;
}

.game-board {
    display: inline-block;
}

.frame {
    display: inline-block;
    background-color: #6ed17d;
    padding: 20px;
    box-shadow: 0 3px 5px rgba(0, 0, 0, 0.8);
    color: white;
}

.piece-options {
    position: absolute;
    line-height: 50px;
    left: 50%;
    transform: translateX(-50%) scale(0);
    top: 400px;
    z-index: 2;
    transition: transform 0.3s;
    transition-timing-function: cubic-bezier(0, 1.11, 0.43, 1.2);
}

.cover {
    position: absolute;
    background-color: #1d5525dc;
    width: 490px;
    height: 490px;
    z-index: 1;
    transform: translate(-20px, -20px) scale(0);
    transition: transform 0.2s;
    transition-timing-function: cubic-bezier(0, 1.11, 0.43, 1.2);
}

.game-type {
    position: absolute;
    left: 50%;
    transform: translateX(-50%) scale(0);
    top: 300px;
    z-index: 2;
    transition: transform 0.32s;
    transition-timing-function: cubic-bezier(0, 1.11, 0.43, 1.2);
    white-space: nowrap;
}

.begin {
    position: absolute;
    left: 50%;
    transform: translateX(-50%) scale(0);
    top: 500px;
    z-index: 3;
    transition: transform 0.32s;
    transition-timing-function: cubic-bezier(0, 1.11, 0.43, 1.2);
}

.begin > .piece-btn {
    padding: 5px 15px;
}

.game {
    display: grid;
    grid-template-columns: repeat(3, 150px);
    grid-template-rows: repeat(3, 150px);
}

.slot {
    line-height: 150px;
    font-size: 80px;
    /* To make text unselectable */
    -webkit-user-select: none;
    /* Safari */
    -moz-user-select: none;
    /* Firefox */
    -ms-user-select: none;
    /* IE10+/Edge */
    user-select: none;
    /* Standard */
    /*  */
    
}

.mark {
    color: white;
    transform: scale(0);
    transition: transform 0.3s, color 0.3s;
    transition-timing-function: cubic-bezier(0, 1.11, 0.43, 1.2);
    
}

.middle {
    border-bottom: 5px solid white;
    border-top: 5px solid white;
}

.center {
    border-left: 5px solid white;
    border-right: 5px solid white;
}

.piece-btn {
    background-color: #6ed17d;
    display: inline-block;
    font-size: 25px;
    color: white;
    margin: 15px;
    box-shadow: 0 3px 5px rgba(0, 0, 0, 0.8);
    transition: background-color 0.3s;
    /* To make text unselectable */
    -webkit-user-select: none;
    /* Safari */
    -moz-user-select: none;
    /* Firefox */
    -ms-user-select: none;
    /* IE10+/Edge */
    user-select: none;
    /* Standard */
    /*  */
}

.restart {
    position: absolute;
    left: 50%;
    transform: translateX(-50%) scale(0);
    top: 500px;
    z-index: 3;
    transition: transform 0.32s;
    transition-timing-function: cubic-bezier(0, 1.11, 0.43, 1.2);
}

.restart > .piece-btn {
    padding: 10px 15px;
    font-size: 20px;
}

.end-message {
    position: absolute;
    left: 50%;
    transform: translateX(-50%) scale(0);
    top: 300px;
    z-index: 4;
    transition: transform 0.32s;
    transition-timing-function: cubic-bezier(0, 1.11, 0.43, 1.2);
    white-space: nowrap;
}

.end-message > .piece-btn {
    padding: 10px 15px;
    font-size: 50px;
}

.buttonX {
    width: 50px;
    height: 50px;
}

.buttonO {
    width: 50px;
    height: 50px;
}

.player {
    padding: 10px 15px;
    font-size: 20px;
}

.piece-btn:hover {
    background-color: #35f852;
    cursor: pointer;
}

.piece-btn:active {
    transform: translateY(3px);
    box-shadow: none;
}