body {
    background: #f4f6fb;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    font-family: 'Segoe UI', Arial, sans-serif;
}
.card, .ukol {
    background: white;
    border-radius: 16px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.10);
    padding: 2.5rem 2rem;
    min-width: 330px;
    max-width: 96vw;
    margin-bottom: 2rem;
    text-align: center;
}
.pozdrav {
    color: #2a7ae2;
    font-size: 1.6rem;
    font-weight: bold;
    margin-bottom: 1.3rem;
}
.datum {
    font-size: 1.2rem;
    color: #58595b;
    margin-bottom: 0.5rem;
}
.svatek {
    font-size: 1.1rem;
    color: #178c3a;
    margin-top: 1.5rem;
    font-weight: bold;
}
.ukol h2 {
    color: #6c479c;
    font-size: 1.2rem;
    margin-bottom: 1.1rem;
}
.ukol b {
    color: #2a7ae2;
}
.ukol .hlaska {
    color: #d33a2c;
    font-weight: bold;
}