html,
body {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background: black;
    font-family: Arial, Helvetica, sans-serif;
}

* {
    box-sizing: border-box;
}

[hidden] {
    display: none !important;
}

#introduction {
    position: fixed;
    inset: 0;
    overflow: hidden;
    background: black;
}

.scene {
    position: fixed;
    inset: 0;

    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;

    opacity: 0;
    transform: scale(1);
    transform-origin: center center;
}

#shade {
    position: fixed;
    inset: 0;
    z-index: 10;
    pointer-events: none;

    background: linear-gradient(
        to bottom,
        rgba(0, 0, 0, 0.00) 0%,
        rgba(0, 0, 0, 0.02) 48%,
        rgba(0, 0, 0, 0.72) 100%
    );
}

#welcomePanel {
    position: fixed;
    left: max(18px, env(safe-area-inset-left));
    right: max(18px, env(safe-area-inset-right));
    bottom: max(22px, env(safe-area-inset-bottom));
    z-index: 20;

    width: min(720px, calc(100% - 36px));
    margin: 0 auto;
    padding: 18px 20px;

    border: 1px solid rgba(255, 255, 255, 0.42);
    border-radius: 24px;

    color: white;
    text-align: center;
    background: rgba(28, 18, 10, 0.78);
    box-shadow: 0 12px 35px rgba(0, 0, 0, 0.38);
}

#message {
    margin: 0;
    font-size: clamp(1.45rem, 4.4vw, 2.35rem);
    line-height: 1.15;
    text-wrap: balance;
}

#buttonRow {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 14px;
    margin-top: 18px;
}

button {
    min-width: 150px;
    padding: 13px 24px;

    border: 0;
    border-radius: 999px;

    color: #3d2409;
    background: #ffd86f;

    cursor: pointer;
    font: inherit;
    font-weight: 750;
    text-transform: lowercase;

    box-shadow: 0 5px 14px rgba(0, 0, 0, 0.28);
    touch-action: manipulation;
}

button:active {
    transform: scale(0.97);
}

button:disabled {
    opacity: 0.62;
    cursor: default;
}

#loader {
    display: grid;
    justify-items: center;
    gap: 7px;
    margin-top: 18px;
}

#loader p {
    margin: 0;
    font-weight: 700;
}

.spinner {
    width: 48px;
    height: 48px;

    border: 5px solid rgba(255, 255, 255, 0.28);
    border-top-color: #ffd86f;
    border-radius: 50%;

    animation: spin 850ms linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

@media (orientation: landscape) {
    #welcomePanel {
        padding: 15px 20px;
    }

    #message {
        font-size: clamp(1.3rem, 3vw, 2rem);
    }
}