body {
    background: url("./bkg.jpg");
    background-size: cover;
    background-position: center;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
    margin: 0;
    padding: 0;
}

.banner {
    display: block;
    width: 90%;
    max-width: 700px;
    height: auto;
    margin: 10px auto;
}

h2 {
    color: white;
    text-align: center;
}

#board {
    margin: 0 auto;
    display: flex;
    flex-wrap: wrap;
    background-color: whitesmoke;
    border: 10px solid lightgrey;
    width: 709px;
    box-sizing: border-box;
}

.card {
    width: 135px;
    height: 192px;
    margin: 3px;
}

button {
    background-color: #7c3aed;
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 18px;
    font-weight: bold;
    border-radius: 10px;
    cursor: pointer;
    margin-top: 15px;
}

button:hover {
    background-color: #6d28d9;
}

.leaderboard-section {
    width: 90%;
    max-width: 350px;
    margin: 10px auto 20px;
    padding: 12px;
    background: rgba(255, 255, 255, 0.92);
    border: 3px solid gold;
    border-radius: 12px;
    color: #2d1b69;
    box-sizing: border-box;
}

.leaderboard-section h3 {
    margin: 0 0 8px;
    color: #5b21b6;
}

#leaderboard {
    display: inline-block;
    text-align: left;
    margin: 0;
    padding-left: 25px;
    font-size: 18px;
    font-weight: bold;
    color: black;
}

#leaderboard li {
    margin: 4px 0;
}

.popup-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.75);
    justify-content: center;
    align-items: center;
    z-index: 9999;
    padding: 15px;
    box-sizing: border-box;
}

.certificate {
    background: white;
    color: #2d1b69;
    width: 90%;
    max-width: 500px;
    max-height: 85vh;
    overflow-y: auto;
    padding: 20px;
    border: 8px double gold;
    border-radius: 18px;
    text-align: center;
    box-shadow: 0 0 30px rgba(255, 215, 0, 0.65);
    box-sizing: border-box;
}

.certificate h1 {
    margin-top: 0;
    color: #7c3aed;
    font-size: 34px;
}

.certificate h2 {
    color: #2d1b69;
}

.score-text {
    font-size: 22px;
    font-weight: bold;
}

#initialsInput {
    display: block;
    width: 100px;
    margin: 12px auto;
    padding: 10px;
    font-size: 24px;
    font-weight: bold;
    text-align: center;
    text-transform: uppercase;
    border: 2px solid #7c3aed;
    border-radius: 8px;
}

.worksheets {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 30px;
    flex-wrap: wrap;
}

.worksheet {
    text-align: center;
}

.thumbnail {
    width: 200px;
    height: auto;
    border: 2px solid #7c3aed;
    border-radius: 8px;
    display: block;
    margin-bottom: 10px;
}

.worksheet button {
    padding: 8px 16px;
    font-size: 16px;
    border-radius: 6px;
}

.thanks-section {
    max-width: 800px;
    margin: 30px auto;
    padding: 20px;
    background: rgba(255, 255, 255, 0.08);
    border: 2px solid gold;
    border-radius: 12px;
    color: white;
    text-align: center;
    box-sizing: border-box;
}

.thanks-section h3 {
    color: gold;
    margin-bottom: 10px;
}

@media screen and (max-width: 600px) {
    body {
        overflow-x: hidden;
    }

    .banner {
        width: 95%;
        margin-top: 6px;
    }

    h2 {
        font-size: 20px;
        margin: 8px 0;
    }

    #board {
        width: 95vw;
        max-width: 360px;
        border-width: 5px;
    }

    .card {
        width: calc((95vw - 50px) / 5);
        max-width: 62px;
        height: auto;
        aspect-ratio: 135 / 192;
        margin: 2px;
    }

    button {
        font-size: 15px;
        padding: 10px 18px;
    }

    .leaderboard-section {
        max-width: 340px;
        padding: 10px;
        margin: 8px auto 12px;
    }

    #leaderboard {
        font-size: 15px;
    }

    .certificate {
        width: 95%;
        max-width: 330px;
        padding: 15px;
    }

    .certificate h1 {
        font-size: 24px;
    }

    .certificate h2 {
        font-size: 18px;
    }

    #initialsInput {
        width: 90px;
        font-size: 20px;
    }

    .worksheets {
        flex-direction: column;
        align-items: center;
        gap: 25px;
    }

    .thumbnail {
        width: 160px;
    }

    .thanks-section {
        width: 90%;
        padding: 15px;
    }
}