I would add a max-width: 100%; on "input, .input_text, button, select", not sure if it could break anything (I humbly don't think so?), but it would surely fix it.
input, button, select, textarea, .editor {
border: 1px solid #ccc;
border-radius: 2px;
background: #fff;
color: #666;
make it
input, button, select, textarea, .editor {
border: 1px solid #ccc;
border-radius: 2px;
background: #fff;
color: #666;
max-width: 100%;
For the board index... .board_name {
padding: 0 0 1px 0;
font-size: 1.143em;
to
.board_name {
padding: 0 0 1px 56px;
font-size: 1.143em;
Do I like it? No, just don't use ridiculously long names, lol.
Did I test it? Of course not 
ETA: I'm talking about index.css, didn't mention the file.