.messageTextInput{
    padding: 10px;
    width: 60%;
    height: 10%;
    border: 1px solid black;
    margin-right: 3%;
}
.messageTextInput:focus {
    background-color: #ccffec;
}

.chatWindow {
    padding: 10px;
    width: 75%;
    height: 75%;
    float: left;
    border: 1px solid black;
}

.lobby {
    padding: 10px;
    width: 17%;
    height: 75%;
    float: right;
    border: 1px solid black;
}

.sendButton {
    padding: 10px;
    width: 10%;
    height: 10%;
    border:0px solid black;
    font-size: 1em;
}
.sendButton:hover {
    font-size: 0.92em;
    background-color: #07ffb2;
}
.sendButton:active {
    background-color: #11a474;
    position:relative;
}

.browserChatView{
    padding:10px;
    height: 95vh;
    border:1px solid black;
}

.messageTextInput{
    padding: 10px;
    width: 60%;
    height: 10%;
    border: 1px solid black;
    margin-right: 3%;
}
.messageTextInput:focus {
    background-color: #ccffec;
}

.chatWindow {
    padding: 10px;
    width: 75%;
    height: 75%;
    float: left;
    border: 1px solid black;
}

.lobby {
    padding: 10px;
    width: 17%;
    height: 75%;
    float: right;
    border: 1px solid black;
}

.sendButton {
    padding: 10px;
    width: 10%;
    height: 10%;
    border:0px solid black;
    font-size: 1em;
}
.sendButton:hover {
    font-size: 0.92em;
    background-color: #07ffb2;
}
.sendButton:active {
    background-color: #11a474;
    position:relative;
}

.browserChatView{
    padding:10px;
    height: 95vh;
    border:1px solid black;
}
@media only screen and (max-width : 480px) and (max-height: 800px) {
    .chatWindow {
        width: 65%;
        height: 75%;
    }
    .sendButton {
        padding: 10px;
        width: 24%;
        height: 14%;
        font-size: 1em;
        float: right;
    }
    .messageTextInput{
        padding: 10px;
        width: 65%;
        height: 10%;
        border: 1px solid black;
        float: left;
    }
    .browserChatView{
        height: 100vh;
    }
}

Fix responsive on window resize
Fix responsive on window resize
