响应式 2 列 CSS 布局，包括固定宽度的侧边栏？

在任何地方都找不到这个问题的解决方案（我猜这一定是一个非常常见的问题）。

我正在创建一个带有侧边栏的响应式设计，其中侧边栏需要具有 200px 的固定宽度，并且高度未知。我怎样才能使主要内容区域占据所有剩余宽度，而不会出现任何异常行为。

我最接近的是以下内容，但它的问题是侧边栏可能与页脚重叠。任何人都可以建议修复我的代码，或者与我分享一些有效的代码吗？

            * {
            padding: 0;
            margin: 0;
            outline: 0;
            -moz-box-sizing: content-box;
            -webkit-box-sizing: content-box;
            box-sizing: content-box;
        }
        body {
            background: orange;
        }
        #container {
            max-width: 1000px;
            min-width: 768px;
            margin: 0 auto;
            background: yellow;
            position: relative;
            height: 100%;
        }
        #header {
            background: purple;
            color: white;
            text-align: center;
            padding: 10px;
        }
        #main {
            position: relative;
        }
        aside {
            background: blue;
            width: 200px;
            color: white;

            position: absolute;
            top: 0;

            /* change this to "right: 0;" if you want the aside on the right. Also, change the "margin-left" code, below. */
            left: 0;

            padding-top: 20px;
            padding-bottom: 20px;

            padding-left: 10px; /* If you change this value, remember to change the margin-left value of #primary */
            padding-right: 10px; /* ditto */
        }
        #primary {
            background: red;

            /* change this to margin-right if you want the aside on the right. Also change the "left" code, above. */
            margin-left: 220px; /* aside_width + aside_left_padding + aside_right_padding = 200px + 10px + 10px */
            padding: 1em; /* whatever */
        }
        #footer {
            background: green;
            color: white;
            padding: 10px;
            position: absolute;
            bottom: 0;
            left: 0;
            right: 0;
        }

        <div id="container">
        <div id="header">
            <h1>LAYOUT TEST #2</h1>
        </div>
        <div id="main">
            <div id="primary">
                <h2>THIS IS THE MAIN CONTENT ** THIS IS THE MAIN CONTENT ** THIS IS THE MAIN CONTENT</h2>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <h2>sub heading</h2>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <h2>sub heading</h2>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
            </div>
            <aside>
                <h3>navigation (left)</h3>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
                <p>lorem ipsum</p>
            </aside>
        </div>
        <div id="footer">
            <h1>LAYOUT TEST #2</h1>
        </div>
    </div>

1 = 使用弹性盒：http://jsfiddle.net/rudiedirkx/CjWbv/2/

#main {
    display: flex;
}
#primary {
    background: #bbb;
    flex: 1;
}
aside {
    background: #ddd;
    flex: 0 0 200px;
}

2 = 与calc(): http://jsfiddle.net/rudiedirkx/CjWbv/

#main:after { clearfix here }
#primary {
    float: left;
    background: #bbb;
    width: calc(100% - 200px);
}
aside {
    background: #ddd;
    float: right;
    width: 200px;
}

两者都需要对旧版浏览器（和供应商前缀）进行回退。从其他答案中选择。