CSS - Horizontal Layout (Center)

How to arrange horizontally css element

See CSS Block - Align (Left, Center, Right)

See CSS Flex - Align (Left, Right, Center)

.container {
   display: flex;
   justify-content: center;
   align-items: center;
}
.child {
   border: 1px solid aqua;
}

<div class="container">
   <div class="child">Am I ...?</div>
</div>

.container {
   display: grid;
   place-items: center
}

<div class="container">
   <div style="border:1px solid black">Am I ...?</div>
</div>

In case of absolute positioning:

.relative {
    position: absolute;
    left: 50%;
    transform: translate(-50%, 0);
}

where:

• left:50%: the block starts at 50% left going to the right
• transform: translate(-50%, 0): then transform with a translate of 50% of the box length to the left