body {
    margin: 0;
    font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto,
        "Helvetica Neue", Arial;
    background: linear-gradient(180deg, #0f1724, #061022);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100vh;
    color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
}

h3 {
    font-size: 1.1em;
    color: #b8bfc39f;
    font-weight: 400;
    text-align: center;
    margin-top: 0px;
}

/* card container */
.card {
    width: min(320px, 96%);
    background: #0000005f;
    border-radius: 12px;
    padding: 22px;
    box-shadow: 0 6px 20px rgba(2, 6, 23, 0.6),
        inset 0 1px 0 rgba(255, 255, 255, 0.02);
    border: 1px solid rgba(13, 33, 51, 0.04);
    text-align: center;
}

/* Choices row */
.choices {
    display: flex;
    gap: 14px;
    justify-content: center;
    margin: 12px 0 18px;
}

/* Symbol buttons */
.choice {
    display: inline-grid;
    place-items: center;
    width: 74px;
    height: 74px;
    border-radius: 14px;
    border: 1px rgba(255, 255, 255, 0.262);
    background: linear-gradient(0deg, #fffbfb4c, #0c70f347);
    font-size: 30px;
    cursor: pointer;
    transition: transform 0.12s ease, box-shadow 0.12s ease;
    box-shadow: 0 8px 20px rgba(11, 43, 60, 0.04);
}

/* visually emphasize the selected choice */
.choice[aria-pressed="true"] {
    transform: translateY(-4px) scale(1.03);
    box-shadow: 0 16px 36px rgba(11, 43, 60, 0.1);
    background: linear-gradient(180deg, #e8f0ff, #dfeeff);
    border-color: rgba(11, 97, 255, 0.18);
}

/* hover/focus states */
.choice:hover,
.choice:focus {
    transform: translateY(-3px);
    outline: none;
    box-shadow: 0 12px 30px rgba(11, 43, 60, 0.06);
}

/* keyboard focus ring for accessibility */
.choice:focus-visible {
    box-shadow: 0 0 0 4px rgba(11, 97, 255, 0.12);
}

/* Display area */
.display {
    display: grid;
    gap: 8px;
    margin-top: 8px;
    justify-items: center;
}

.display > div {
    font-size: 15px;
    color: #25414f;
    background: #fff;
    padding: 8px 12px;
    border-radius: 8px;
    min-width: 240px;
    border: 1px solid rgba(11, 43, 60, 0.04);
}

/* emphasise the result value */
.display .value {
    font-weight: 700;
    margin-left: 6px;
    color: #0b2b3b;
}

/* responsive */
@media (max-width: 480px) {
    .choice {
        width: 62px;
        height: 62px;
        font-size: 26px;
    }
    .display > div {
        min-width: 200px;
        font-size: 14px;
        padding: 8px;
    }
    .card {
        padding: 16px;
        border-radius: 10px;
    }
}