#btn {
    width: 100vw;
    justify-content: center;
    display: flex;
    flex-direction: row;
    gap: 10px;
    align-items: center;
    /* padding: 20px; */
    height: 5vh;
}

.nav-btn, .mode-btn {
    background-color: #2d333b;
    color: white;
    border: 1px solid #444c56;
    border-radius: 4px;
    padding: 10px 20px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.nav-btn:hover, .mode-btn:hover {
    background-color: #444c56;
    border-color: #5c6e77;
}

.nav-btn:active, .mode-btn:active {
    background-color: #5c6e77;
    border-color: #6f7f88;
}

.nav-btn {
    /* width: 120px; */
    text-align: center;
    font-weight: bold;
}

.mode-btn {
    width: 100px;
}

#btn > div {
    display: flex;
    gap: 10px;
}


#graph {
    width: 100%;
    height: 90vh; 
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    flex-direction: row;
    align-items: center;

}

#div_c1, #div_c2, #div_c3, #math {
    display: block;
    width: calc(50% - 25px); 
    height: calc(50% - 25px); 
    display: flex;
    justify-content: center;
    align-items: center;
}

#time_chart, #commit_stat_chart, #language_chart {
    width: 100%;
    height: 100%;
}