/*
 * Author:        Pierre-Henry Soria <ph7software@gmail.com>
 * Copyright:     (c) 2012-2016, Pierre-Henry Soria. All Rights Reserved.
 * License:       GNU General Public License; See PH7.LICENSE.txt and PH7.COPYRIGHT.txt in the root directory.
 */

#cache_chart {
    height: 400px;
    width: 600px;
}

#free_space_chart {
    height: 420px;
    width: 620px;
}

#user_chart {
    height: 300px;
    width: 100%;
    margin-bottom: 8px;
    border: 1px solid #ccc;
}

table, td, th {
    border: 1px solid gray;
}

/*
 * Author:        Pierre-Henry Soria <ph7software@gmail.com>
 * Copyright:     (c) 2012-2016, Pierre-Henry Soria. All Rights Reserved.
 * License:       GNU General Public License; See PH7.LICENSE.txt and PH7.COPYRIGHT.txt in the root directory.
 */

#cache_chart, #free_space_chart, #user_chart {
    width: 100%;
    margin-bottom: 8px;
    border: 1px solid #ccc;
}
#cache_chart, #free_space_chart {
    height: 350px;
}
#user_chart {
    height: 300px;
}

table, td, th {
    border: 1px solid gray;
}

Make cache chart responsible + border
Make cache chart responsible + border
