html, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}

body {
    background-image: linear-gradient(#fec8d8, #ffdfd3);
    line-height: 1.5;
    font-family: 'Source Sans Pro', sans-serif;
    color: #111;
    max-width: 700px;       /* instead of fixed width */
    width: 95%;             /* shrink on small screens */
    margin: 0 auto;
    overflow-x: hidden;     /* remove horizontal scrollbar */
}

.container {
    margin: 2% auto;
    padding: 15px;
    background-color: #FFFFFF;
    box-shadow: 0px 1px 4px rgba(0, 0, 0, 0.2);
    box-sizing: border-box;
}

h1 {
    font-size: 3rem;
    font-weight: 900;
    text-align: center;
    margin: 1% 0 3%;
}

textarea {
    width: 100%;
    height: 250px;
    padding: 10px;
    border: 1px solid #d9d9d9;
    outline: none;
    font-size: 1rem;
    resize: vertical;       /* allow vertical resize only */
    line-height: 1.5rem;
    box-sizing: border-box; /* prevents overlap */
}

textarea:hover {
    border-color: #C0C0C0;
}

textarea:focus {
    border-color: #4D90FE;
}

.output.row {
    width: 100%;
    border: 1px solid #DDD;
    font-size: 1.4rem;
    margin: 1% 0;
    background-color: #F9F9F9;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    box-sizing: border-box;
}

.output.row div {
    flex: 1 1 45%;
    padding: 10px 15px;
    box-sizing: border-box;
}

.output.row span {
    font-weight: bold;
    font-size: 1.5rem;
}

#readability {
    font-weight: bold;
}

#readability:hover {
    background-color: #4D90FE;
    color: #FFF;
    border-radius: 2px;
    cursor: pointer;
}

#readability:active {
    background-color: #307AF3;
}

.keywords {
    display: none;
    margin: 4% 0 0;
    font-size: 2rem;
    font-weight: 900;
}

.keywords ul {
    font-weight: 400;
    border: 1px solid #DDD;
    font-size: 1.4rem;
    background-color: #F9F9F9;
    margin: 2% 0;
    padding: 0;
}

.keywords li {
    display: inline-block;
    width: 44%;
    padding: 10px;
    margin: 1%;
}

/* Responsive styles */
@media (max-width: 750px) {
    .output.row {
        font-size: 1.2rem;
    }
    .output.row span {
        font-size: 1.3rem;    
    }
    .keywords ul {
        font-size: 1.2rem;
    }
}

@media (max-width: 600px) {
    .output.row {
        flex-direction: column;
        font-size: 1.1rem;
    }
    .output.row div {
        flex: 1 1 100%;
        padding: 8px 10px;
    }
}