body {
    font-family: sans-serif;
    padding: 10px;
    margin: 0;
    background-color: aliceblue;
    box-sizing: border-box;
}

.container {
    max-width: 720px;
    margin: auto;
    padding: 10px 20px 20px 20px;
}

.parent-block {
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 18px;
    flex-wrap: wrap;
}

.parent-title {
    font-size: 1.2rem;
    font-weight: bold;
    width: 100px;
    flex: 0 0 auto;
}

.selectors {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    flex: 1 1 200px;
}

.select-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.select-group label {
    font-size: 0.9rem;
    color: #555;
}

select {
    padding: 8px;
    font-size: 1rem;
}

select.blood {
    width: 70px;
}

select.rh {
    width: 60px;
}

#result {
    margin-top: 18px;
    font-weight: bold;
    color: #2c3e50;
    min-height: 24px;
}

#explanation {
    margin-top: 20px;
    color: #333;
    line-height: 1.4;
}

#description {
    text-align: center;
    max-width: 900px;
    margin: 0 auto 24px auto;
}

/* used for the title at the top of the page and also the title when embedded in an iframe - centers the text and adds spacing below */
h2 {
    text-align: center;
    margin: 0 0 12px 0;
}