body {
    background-color: #f8f9fa;
    font-family: Arial, sans-serif;
}

.container {
    max-width: 800px;
    margin: auto;
    padding: 20px;
}

.card {
    margin-top: 20px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    border: none;
    border-radius: 10px;
}

.card-body {
    padding: 20px;
}

.card-title {
    font-size: 1.25rem;
    font-weight: bold;
    margin-bottom: 15px;
}

.form-control {
    margin-bottom: 15px;
}

.btn-primary {
    width: 100%;
    padding: 10px;
    font-size: 1rem;
}

#averageDuration, #nextCycle {
    font-weight: bold;
}

#fertilePeriodMessage {
    color: #555;
    font-style: italic;
}

.btn-danger {
    margin-top: 20px;
}

ul {
    list-style-type: none;
    padding: 0;
}

ul li {
    background-color: #fff;
    padding: 10px;
    margin-bottom: 10px;
    border-radius: 5px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.modal-content {
    border-radius: 10px;
}

.modal-header {
    border-bottom: none;
}

.modal-footer {
    border-top: none;
}

#calendar {
    margin-top: 20px;
}