style.css

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

:root {
    --time: 1s;
}


#container {
    display: none;
    background-color: #21D4FD;
    background-image: linear-gradient(19deg, #0E1353 0%, #B721FF 100%);
    height: 100vh;
    width: 100vw;
    justify-content: space-around;
    align-items: center;
    flex-direction: column;
    transition-duration: 1s;
}

#start {
    background-color: #00DBDE;
    background-image: linear-gradient(90deg, #00DBDE 0%, #FC00FF 100%);
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
}

#start h1 {
    font-size: 6vw;
    margin-top: 5vh;
    margin-bottom: 8vh;
    color: lightyellow;
    text-align: center;
}

#players-form {
    background-color: #0093E9;
    background-image: linear-gradient(160deg, #0093E9 0%, #80D0C7 100%);
    border: 1px solid white;
    -webkit-box-shadow: 6px 13px 87px -21px rgba(0, 0, 0, 0.64);
    -moz-box-shadow: 6px 13px 87px -21px rgba(0, 0, 0, 0.64);
    box-shadow: 6px 13px 87px -21px rgba(0, 0, 0, 0.64);
    border-radius: 2rem;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    justify-content: stretch;
    align-items: stretch;
    width: max(40vw, 400px);
    height: max-content;
}

#players-form label,
input {
    font-family: Georgia, 'Times New Roman', Times, serif;
    margin: 1vh 0;
    text-align: center;
    font-size: 3vw;
}

#submit_btn {
    border-radius: 3em;
    background-color: #f4511e;
    border: none;
    color: #FFFFFF;
    text-align: center;
    font-size: 2vw;
    padding: 20px;
    transition: all var(--time);
    cursor: pointer;
    margin: 5px;
    transition-duration: var(--time);
    border: 2px solid white;
}

#submit_btn:hover {
    background-color: #34495e;
    border-color: #d7ff8c;
    color: #d7ff8c;
    transition-duration: var(--time);
}

.MyClass {
    display: none;
}

.cards {
    display: flex;
    justify-content: space-evenly;
    width: 100%;
    height: 25vh;
    align-items: center;
    text-align: center;
}

.cards .player1,
.cards .player2 {
    background-color: #34495e;
    border-color: #d7ff8c;
    color: #d7ff8c;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: stretch;
    width: max-content;
    padding: 2vw;
    border-radius: 3rem;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    -webkit-box-shadow: 5px 1px 75px -10px rgba(255, 255, 255, 0.78);
    box-shadow: 5px 1px 75px -10px rgba(255, 255, 255, 0.78);
    font-size: 4vw;
    transition-duration: var(--time);
    cursor: context-menu;
}

.player1:hover,
.player2:hover {
    background-color: #0093E9;
    color: white;
    border: 1px solid white;
    transition-duration: var(--time);
}

.hidden {
    color: transparent;
}


.game {
    margin-top: 3vh;
    display: flex;
    justify-content: stretch;
    align-items: center;
    height: 60vh;
    width: 90vw;

}

.ttt {

    margin: 0 auto;
    background-color: #34495e;
    color: #fff;
    border: 6px solid #2c3e50;
    border-radius: 10px;
    display: grid;
    grid-template: repeat(3, 1fr) / repeat(3, 1fr);
    width: 60vh;
    height: 60vh;

}

.hide {
    display: none !important;
    width: 5vw;
    height: 10vh;
    left: 0;
    bottom: 0;
}

.box {
    border: 6px solid #2c3e50;
    font-family: "Raleway", sans-serif;
    color: white;
    border-radius: 2px;
    font-family: Helvetica;
    font-weight: bold;
    font-size: 9vw;
    display: flex;
    justify-content: center;
    align-items: center;
}

.box:hover {
    border: 6px solid white;
    transition-duration: var(--time);
}

#fname,
#lname {
    border-radius: 1rem;
}


.clear {
    width: 8vw;
    height: 4vw;
    position: absolute;
    bottom: 10px;
    right: 10px;
    background-color: #0093E9;
    color: white;
    border: 2px solid white;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: "Raleway", sans-serif;
    font-size: 2.5vw;
    cursor: pointer;
    border-radius: 1rem;
    transition-duration: var(--time);
}

.clear:hover {
    background-color: #34495e;
    border-color: #d7ff8c;
    color: #d7ff8c;
    transition-duration: var(--time);

}

.turns-card {
    width: max-content;
    height: max-content;
    padding: 10px 20px;
    border: 1px solid;
    background-color: #34495e;
    border-color: #d7ff8c;
    color: #d7ff8c;
    border-radius: 2rem;
    font-size: 2.5vw;
    text-align: center;
    font-weight: 700;
    transition-duration: var(--time);
    cursor: context-menu;
}

.turns-card:hover {
    background-color: #0093E9;
    color: white;
    border: 1px solid white;
    transition-duration: var(--time);
}

.popup {
    width: 40vw;
    height: 20vh;
    border-radius: 5vw;
    background-color: #34495e;
    border-color: #d7ff8c;
    color: #d7ff8c;
    -webkit-box-shadow: 51px 38px 109px 22px rgba(0, 0, 0, 0.64);
    -moz-box-shadow: 51px 38px 109px 22px rgba(0, 0, 0, 0.64);
    box-shadow: 51px 38px 109px 22px rgba(0, 0, 0, 0.64);
    display: flex;
    transition-duration: var(--time);
    justify-content: center;
    align-items: center;
    position: absolute;
    left: 30vw;
    top: 75vh;
    font-size: 5vw;
    text-align: center;
}

.popup::after {
    position: relative;
    top: -10vh;
    right: -5vw;
    background-color: red;
    content: "X";
    border-radius: 50%;
    width: 7vw;
    height: 7vw;
    font-size: 5vw;
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    cursor: pointer;

}

#winner {
    text-align: center;
    padding-left: 3vw;
}