You can add these CSS blocks to your Thesis -> Custom CSS screen

1. Disable the ability to click on a slider image:

.flexslider .slides a {pointer-events: none; cursor: default;}

2. Change the color of the mobile menu:

@media only screen and (max-width: 600px) {
    .menu-primary {
        background: #000 !important;
    }
}

3. Change the header background:

#header {
    background: #fff;
    color: #000;
}

4. Change the various navigation menu color settings:

/* Change the main nav background color */
.menu-primary {
    background: #fff;
    text-shadow: none;
}

/* Change the main nav text links color */
.menu-primary a {color: #000;}

/* Change the main nav background hover and text color */
.menu-primary a:hover, .menu-primary .current a, .menu-primary .current a:hover, .menu-primary .current-cat a, .menu-primary .current-cat a:hover, .menu-primary .current-menu-item a, .menu-primary .current-menu-item a:hover {
    color: #fff;
    background: #000;
}

/* Change the menu right border color */
.menu-primary li {
    background: none;
    border-right: solid 1px #000;
}

/* Change the header search widget background color */
.header-right #s {background: transparent}

5. Add arrows to slider

.flex-direction-nav {display: block;}