.dropdown {
    position: relative;
    width: 75px;
    height: 30px;
    cursor: pointer;
    z-index: 10;
}
.dropdown-btn-origin {
    display: flex;
    align-items: center;
    height: 30px;
    font-size: 15px;
}
.dropdown-btn-text {
    margin-left: 6px;
}
.dropdown-btn-img {
    margin-right: 2px;
}
.selected_class_img {
    transition: all 300ms;
    width: 18px;
    margin-left: auto;
}
.class_arrow_rotate {
    transform: rotate(180deg);
}
.dropdown-expanded {
    max-height: 300px;
}
.dropdown-collapsed {
    max-height: 0;
}
.dropdown-item:not(.select_not_allowed):hover {
    background-color: #3498DB;
    color: white;
    cursor: pointer;
    transition: all 250ms;
}
.dropdown-item {
    padding: 3px 6px;
    height: 20px;
    font-size: 16px;
    display: flex;
    align-items: center;
    color: black;
}
.dropdown-item.select_not_allowed {
    cursor: not-allowed;
    color: #818181;
}
.dropdown-content {
    background-color: #f1f1f1;
    box-shadow: 3px 3px 12px 0 rgba(0,0,0,0.2);
    transition: all 250ms;
    font-size: 15px;
    z-index: 4;
    position: absolute;
    width: 100%;
}