.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
}

.header h1 {
    margin: 0;
    flex-grow: 1;
    text-align: center;
}

.settings {
    position: relative;
}

.icon-button {
    font-size: 24px;
    cursor: pointer;
    margin: 5px;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.3s, border-color 0.3s;
}

.settings-menu {
    display: none;
    position: absolute;
    top: 50px;
    right: 0;
    flex-direction: column;
}

.settings-menu.visible {
    display: flex;
}

.group {
    margin-bottom: 40px;
}

.group-title {
    display: inline-block;
    cursor: pointer;
}

.group-icon {
    margin-right: 8px;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .router {
        flex: 1 1 calc(50% - 20px);
        max-width: calc(50% - 20px);
    }
}

@media (max-width: 768px) {
    .router {
        flex: 1 1 calc(50% - 20px);
        max-width: calc(50% - 20px);
    }
}

@media (max-width: 480px) {
    .router {
        flex: 1 1 100%;
        max-width: 100%;
    }
}