style.css

body {
    color: #ddd;
    background-color: #333;
    font-family: sans-serif;
    font-size: 14px;
}

form {
    margin-bottom: 20px;
}

input[type="text"] {
    background-color: transparent;
    border: none;
    border-bottom: 1px solid #999;
    margin-right: 20px;
    outline: none;
    color: inherit;
    font-size: inherit;
}

input[type="checkbox"] {
    margin-right: 5px;
}


em {
    font-style: normal;
    color: #8BD;
    border-bottom: 1px dotted #8BD;
}

ul, ol, li {
    list-style-type: none;
    margin: 0;
    padding: 0;
}

.tweets-column {
    width: 360px;
    float: left;
}

.tweets-column + .tweets-column {
    margin-left: 30px;
}

.tweet {
    padding: 5px;
    margin: 5px 0;
    border-bottom: 1px solid #444;
}
/* meh, clearfix */
.tweet:before, .tweet:after {
    content: " ";
    display: table;
}
.tweet:after {
    clear: both;
}


.tweet__avatar {
    float: left;
    width: 48px;
    height: 48px;
    border-radius: 4px;
    margin-right: 10px;
}

.tweet__content {
    float: left;
    width: calc(100% - 58px);
}

.tweet__author {
    font-weight: bold;
}
.tweet__handle {
    color: #777;
    margin-left: 10px;
}