Centering flex item content - html

Question

I have the following flex item (#globalSearchContLi) inside a flex-container. The container is an unordered list.
My problem is that I'm creating a fun looking search bar with a half-sphere submit button. The button is pretty much attached to the search bar with inline-block and margin properties.
This bundle (the search bar and button) won't center in the div any way I try to.
I tried setting #globalSearchCont with a specific width and auto side margins, but the whole flexbox presentation won't display correctly on mobile.
Any suggestions/advice? Thanks in advance.
#globalSearchContLi {
flex-grow: 7;
margin: 0px 15px;
flex-basis: 100px;
}
#globalSearchContLi {
flex-grow: 7;
margin: 0px 15px;
flex-basis: 100px;
}
#munchGlobalSearchbar {
width: 240px;
height: 50px;
/* box-shadow: 0 0 0 1px#000,0 0 0 3px #FFF, 0 0 0 5px #333; */
font-weight: 300;
font-size: 1.6rem;
border-radius: 10px;
display: inline-block;
margin-top: 20px;
text-align: center;
background-color: #edad0c;
border-bottom: 2px solid #333;
border-top: 2px solid #333;
border-left: 2px solid #333;
}
#munchGlobalSearchbar::placeholder {
color: #000;
}
#globalSearchBtn {
background-image: url(../imgs/addOn/panEmoji.png);
width: 50px;
height: 51px;
margin: 0px 0px -17px -12px !important;
border-bottom-right-radius: 50%;
border-top-right-radius: 50%;
display: inline-block;
border: 2px solid #333;
background-color: #38b32b;
transition: .2s all ease;
}
.backImageCon {
background-repeat: no-repeat;
background-size: contain;
background-position: center;
}
<li id="globalSearchContLi">
<div id="globalSearchCont">
<input placeholder="Search..." type="textbox" name="globalSearch" id="munchGlobalSearchbar">
<div id="globalSearchBtn" class="backImageCon"></div>
</div>
</li>

Answer 1

Use justify-content: center on the parent to horizontally center the button elements.
#globalSearchContLi {
list-style-type: none;
margin-left: 0;
}
#globalSearchCont {
display: flex;
justify-content: center;
height: 50px;
}
#munchGlobalSearchbar {
width: 240px;
font-weight: 300;
font-size: 1.6rem;
border-radius: 10px;
text-align: center;
background-color: #edad0c;
border-bottom: 2px solid #333;
border-top: 2px solid #333;
border-left: 2px solid #333;
}
#munchGlobalSearchbar::placeholder {
color: #000;
}
#globalSearchBtn {
background-image: url(../imgs/addOn/panEmoji.png);
width: 50px;
border-bottom-right-radius: 50%;
border-top-right-radius: 50%;
border: 2px solid #333;
background-color: #38b32b;
transition: .2s all ease;
margin-left: -10px;
}
.backImageCon {
background-repeat: no-repeat;
background-size: contain;
background-position: center;
}
ul {
margin: 0;
padding: 0;
}
* {
box-sizing: border-box;
}
<ul>
<li id="globalSearchContLi">
<div id="globalSearchCont">
<input placeholder="Search..." type="textbox" name="globalSearch" id="munchGlobalSearchbar">
<div id="globalSearchBtn" class="backImageCon"></div>
</div>
</li>
</ul>