How Can I Perfectly Center a Rotated Element, Especially During Screen Resizing?

Centered Element Eludes Center, Especially upon Screen Resizing

Horizontal alignment of a triangle pointer continues to be elusive, particularly during window size adjustments.

The culprit lies in mistakenly using left: 48% to center the triangle. While this seemingly centers the element, it actually places the left edge of the pointer near the center of its container.

For true centering, the correct approach is left: 50%, which aligns the pointer's center with that of the container. However, this introduces a new problem: the element is shifted right when using left: 50%.

The solution is to utilize the transform property with translate(-50%,0). This rule instructs the triangle to shift left by 50% of its width, effectively centering it on the same line as before.

In this specific case, however, applying both transform: rotate(45deg) and transform: translate(-50%,0) presents a challenge. The cascade overrides the second transform rule, rendering it ineffective.

To resolve this, chaining transform functions is necessary. The corrected code is:

.container::before {
    top: -33px;
    left: 50%;
    transform: translate(-50%,0) rotate(45deg);
    position: absolute;
    border: solid #C2E1F5;
    border-width: 4px 0 0 4px;
    background: #88B7D5;
    content: '';
    width: 56px;
    height: 56px;
}

This modified code now correctly centers the triangle pointer and maintains its position even when the screen is resized.

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