这里是我的代码，我想在底部中心对齐提交按钮，我已经尝试改变它的位置，显示它的容器和底部本身，有什么解决方案吗？ PS:如果我把它留在那里会更好，当调整屏幕大小时，按钮会跳到下一行想要的位置（底部中央），谢谢。

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#datails_container {
    position: relative;
    display: flex;
    background-color: darkgrey;
    width: 70%;
    border-radius: 5px;
    top: 50px; 
    margin: auto;
    border-radius: 6px;
}

.theight {
    padding-bottom: 10px;
    border: 1px black solid;
    margin: auto;
    width: 80%;
    background-color: white;
    border-radius: 4px;
}

form {
    width: 100%;
    height: 100%;
    align-items: center;
    display: flex;
    flex-flow: row wrap;
    justify-content: space-between;
}

span {
    background-color: #b50612;
    width: 92px;
    height: min-content;
    border-radius: 5px;
    position: relative;
    top: -7px;
    left: 12px;
    color: white;
    font-weight: bold;
    text-align: center;
}

#presentaion {
    color: wheat;
    width: 100%;
    position: absolute;
    text-align: center;
}

#detsubmitter {
    position: absolute;
    border: 1px solid black;
    display: block;
    right: 5px;
    bottom: 6px;
    background-color: green;
    border-radius: 4px;
    height: 2.6em;
}

#detsubmitter:hover {
    cursor: pointer;
}

.itemcount {
    font-size: 16px;
    font-family: sans-serif;
    font-weight: 700;
    color: #444;
    line-height: 1.3;
    padding: .6em 1.4em .6em 1.4em;
    box-sizing: border-box;
    margin: 0;
    border: 1px solid #aaa;
    box-shadow: 0 1px 0 1px rgba(0, 0, 0, .04);
    border-radius: .5em;
    appearance: none;
    background-color: #fff;
    height: 40px;
    display: flex;
}

label {
    top: 28px;
    left: -65px;
    height: min-content;
    width: 79.9667px !important;
    display: inline-flex;
    font-weight: bold;
    color: black;
    display: flex;
}

input {
    height: 25px;
    border-radius: 5px;
    position: relative;
}

<div id="datails_container"  > 
        <form id="" action="" method="post">
            <div id="genre_cont" class="theight" style="margin-top: 75px;">
                <span>Genres</span>
                <select name="gnerenmbr" class="itemcount" id="gnerenmbr">
                    <option value="01">1</option>
                    <option value="02">2</option>
                    <option value="03">3</option>
                    <option value="04">4</option>
                    <option value="05">5</option>
                    <option value="06">6</option>
                    <option value="07">7</option>
                    <option value="08">8</option>
                    <option value="09">9</option>
                </select>
                <label for="gnerenmbr">genre(s):</label>
                <input type="text" placeholder="input 1">
                <input type="text"  placeholder="input 2">
                <input type="text" placeholder="input 3">
                <input type="text" placeholder="input 4">
            </div>
            <br>
            <div id="language_cont" class="theight">
                <span>Languages</span>
                <select name="languagenmbr" class="itemcount" id="languagenmbr">
                    <option value="01">1</option>
                    <option value="02">2</option>
                    <option value="03">3</option>
                    <option value="04">4</option>
                    <option value="05">5</option>
                    <option value="06">6</option>
                    <option value="07">7</option>
                    <option value="08">8</option>
                    <option value="09">9</option>
                </select>
                <label for="languagenmbr">Language(s):</label>
                <input type="text" placeholder="input 1">
                <input type="text"  placeholder="input 2">
                <input type="text" placeholder="input 3">
            </div>
            <br>
            <div id="country_cont" class="theight">
                <span>Countries</span>
                <select name="countrynmbr" class="itemcount" id="countrynmbr">
                    <option value="01">1</option>
                    <option value="02">2</option>
                    <option value="03">3</option>
                    <option value="04">4</option>
                    <option value="05">5</option>
                    <option value="06">6</option>
                    <option value="07">7</option>
                    <option value="08">8</option>
                    <option value="09">9</option>
                </select>
                <label for="countrynmbr">country(ies):</label>
                <input type="text" placeholder="input 1">
                <input type="text"  placeholder="input 2">
            </div>
            <button id="detsubmitter" type="submit">ADD details</button>
        </form>
    </div>

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