这个搜索框代码怎么写的不对

大哥们，看一下我这个代码怎么写的不对啊

    <div class="search-main">
        <div class="inner">
                <h2>3D Scientific Visualization </h2>
            <form class="search"action="/index.php" method="get">
                <input type="hidden" name="c" value="store">
                <input class="key" type="text" name="keywords" placeholder="PPT / PNG / OBJ / C4D / EPS">
                <button type="submit" class="iconfont icon-sousuo submit"></button>
            </form>
         
            <p class="adv">系统的科学模型素材库</p>
            </div>
        <div class="canvas-bg" id="bg"></div>
    </div>