CSS positioning riddle

? Why don't the boxes fit the container ?

by j08691

HTML

<div class="container">
    <div class="one"></div><div class="two"></div><div class="three"></div>
</div>

CSS

.container {
    width: 360px;
    height: 50px;
    border: 1px solid black;
}
.container div {
    width: 120px;
    height: 100%;
    display: inline-block;
}
.one {
    background: blue;
}
.two {
    background: green;
}
.three {
    background: red;
}