.tf-expression {
    font-size: 2rem;
    font-weight: 800;
    text-align: center;
    color: #1a1a2e;
    margin: .5rem 0;
    letter-spacing: .05em;
}

.tf-prompt {
    font-size: 1.1rem;
    font-weight: 700;
    text-align: center;
    color: #475569;
    margin: .3rem 0 .6rem;
}

.tf-options {
    display: flex;
    justify-content: center;
    gap: 1.2rem;
    margin: .8rem 0;
}

.tf-option {
    margin: 0;
    padding: 1rem 2.2rem;
    font-size: 1.4rem;
    font-weight: 800;
    border: 2px solid #cbd5e1;
    border-radius: 14px;
    background: #fff;
    color: #1a1a2e;
    cursor: pointer;
    transition: transform .15s, border-color .15s, background-color .15s;
    min-width: 140px;
}

.tf-option:hover {
    transform: scale(1.06);
}

.tf-true:hover {
    border-color: #22c55e;
    background: #f0fdf4;
}

.tf-false:hover {
    border-color: #ef4444;
    background: #fef2f2;
}