styles.css

/* Password Popup: Whitespace and borders around intro text. */
#availability_password_intro {
    border-bottom: 1px solid #e9ecef;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
}

/* Password Popup: Try to replicate the Moodle core modal look. */
.availability_password_dialogue .moodle-dialogue-wrap {
    border-radius: 0.6rem;
}
.availability_password_dialogue .moodle-dialogue-bd,
.availability_password_dialogue .moodle-dialogue-ft {
    padding: 1rem !important; /* stylelint-disable-line declaration-no-important */
}
.availability_password_dialogue .moodle-dialogue-hd h5 {
    font-size: 1.171875rem !important; /* stylelint-disable-line declaration-no-important */
    font-weight: 700 !important; /* stylelint-disable-line declaration-no-important */
}
.availability_password_dialogue .moodle-dialogue-ft {
    border-top: 1px solid #e9ecef;
    padding-top: 1rem;
}
.availability_password_dialogue .moodle-dialogue-ft .yui3-button {
    background-image: none !important; /* stylelint-disable-line declaration-no-important */
    box-shadow: none !important; /* stylelint-disable-line declaration-no-important */
}