#side_bar {
height: 100%;
    position: fixed;
    z-index: 11;
    top: 0;
    left: 0;
    background-color: #ffcf00;
    overflow-x: hidden;
    transition: 0.5s;
    padding-top: 20px;
    box-shadow: 0px 4px 20px #231F20;
}

.open-side-bar {
    width: 20%;
}

.close-side-bar {
    width: 0px;
}

#side_bar a {
    text-decoration: none;
    clear: both;
}

.first_a {
    padding: 8px 8px 8px 12px;
    font-size: 2.5vw;
    display: block;
    transition: 0.3s;
    color: #f1f1f1;
    text-shadow: 2px 2px 4px #D66A00;
}

.first_a.active {
    background-color: darkorange;
}

#close_sidebar_btn {
    padding: 8px 8px 8px 8px;
    text-decoration: none;
    border: none;
    outline: none;
    cursor: pointer;
    margin-right: 10px;
    overflow: hidden;
    font-size: 3vw;
    color: darkorange;
    background-color: transparent;
    display: block;
    transition: 0.3s;
    float: right;
}

#close_sidebar_btn:hover {
    color: white;
}

.accordion_panel {
    background-color: #daff19;
    max-height: 0;
    overflow: hidden;
    font-size: 1.5vw;
    color: #0D77B7;
    display: block;
    transition: max-height 0.2s ease-out;
}

.accordion_panel a {
    display: block;
    padding: 8px 8px 8px 32px;
    font-weight: 600;
}

.sub-option {
    display: none;
    margin-left: 25px;
    font-size: 1.3vw;
}

#tabs {
    display: none;
}

.active-option {
    color: #0D77B7;
    opacity: 1;
}

.inactive {
    opacity: 0.5;
    color: #337ab7;
}

.accordion_panel a:hover {
    background-color: aquamarine;
    color: whitesmoke;
    opacity: 1;
}

@media (max-width: 767px) {
    
    #side_bar {
        padding-top: 0px;
        line-height: 1;
    }
    
    .open-side-bar {
        width: 28%;
    }
    
    .first_a {
       font-size: 3.5vw;
    }
    
    #close_sidebar_btn {
        font-size: 5vw;
    }
    
    .accordion_panel {
        font-size: 2.5vw;
    }

    .sub-option {
        font-size: 1.7vw;
    }
    
}

@media (min-width: 768px) and (max-width: 1024px) {

    .open-side-bar {
        width: 25%;
    }
  
    .first_a {
        font-size: 3vw;
    }
    
    #close_sidebar_btn {
        font-size: 4vw;
    }
    
    .accordion_panel {
        font-size: 2vw;  
    }
    
}

@media (min-width: 1025px) and (max-width: 1224px) {

    .open-side-bar {
        width: 21%;
    }
    
}