*{margin:0;padding:0;box-sizing:border-box;}

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.main{border:4px solid blue;display: flex; flex-direction: column;height:calc(100vh - 100px)}

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.head{ flex: none; height: 100px; background: #ccc; }

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.list{ height: 100%;  border:4px solid #000; overflow-y: auto;}

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.tabs{height:100px; background: #999;}