Chamfer middle of menu - html

Question

I try to chamfer the middle of the menu but I can't find how to do it in CSS.
Here is what I would like :
Didn't found a good way to do it.
Tried with some pseudo elements and bottom-left & bottom-right radius.
I could take the logo with the bottom things I guess, but I'm pretty sure it's possible to do it CSS way, but I can't find how.
Here is how I structured it :
* {
box-sizing: border-box;
}
ul,
li {
list-style: none;
line-height: 1;
display: inline-block;
}
.header {
line-height: 1;
padding-top: 15px;
background-color: #FFF;
}
.header>div {
display: grid;
grid-column-gap: 90px;
align-items: center;
grid-template-columns: 1fr auto 1fr;
grid-template-areas: "left center right";
}
.header ul.menu>li:not(:first-child) {
margin-left: 35px;
}
.header li {
display: inline-block;
}
.header__left {
grid-area: left;
justify-self: right;
}
.header__center {
grid-area: center;
}
.header__right {
grid-area: right;
}
<header class="header">
<div class="container">
<div class="header__left">
<ul class="menu">
<li>Menu 1</li>
<li>Menu 2</li>
</ul>
</div>
<div class="header__center">
Logo
</div>
<div class="header__right">
<ul class="menu">
<li>Menu 1</li>
<li>Menu 2</li>
</ul>
</div>
</div>
</header>

Answer 1

I'm not sure what went wrong with your attempt at using pseudo-elements, but this seems to work. You might need to fiddle with margins, padding, and position a bit.
* {
box-sizing: border-box;
}
body {
min-height: 100vh;
margin: 0;
padding: 0;
background-image: url(https://picsum.photos/1600);
background-size: cover;
background-color: pink;
}
ul,
li {
list-style: none;
line-height: 1;
display: inline-block;
}
.header {
line-height: 1;
padding: 0 0 5px;
margin-top: 15px;
position: relative;
overflow: hidden;
}
.header .container {
background-color: #fff;
position: relative;
padding-top: 10px;
margin-bottom: 20px;
}
.header::before {
content: '';
position: absolute;
width: 120px;
height: 120px;
border-radius: 60px;
left: 50%;
transform: translateX(-50%);
top: -35px;
background: #fff;
overflow: hidden;
}
.header>div {
display: grid;
grid-column-gap: 90px;
align-items: center;
grid-template-columns: 1fr auto 1fr;
grid-template-areas: "left center right";
}
.header ul.menu>li:not(:first-child) {
margin-left: 35px;
}
.header li {
display: inline-block;
}
.header__left {
grid-area: left;
justify-self: right;
}
.header__center {
grid-area: center;
}
.header__right {
grid-area: right;
}
<header class="header">
<div class="container">
<div class="header__left">
<ul class="menu">
<li>Menu 1</li>
<li>Menu 2</li>
</ul>
</div>
<div class="header__center">
<img src="https://via.placeholder.com/50" />
</div>
<div class="header__right">
<ul class="menu">
<li>Menu 1</li>
<li>Menu 2</li>
</ul>
</div>
</div>
</header>
Fiddle demo