QR Code Component, Flexbox, inherent device scaling, Root Use

What are you most proud of, and what would you do differently next time?

I'm most proud that I wrote the root names and data first, that way when writing my css I knew I could just use a var to add a defined root

        /** Colors **/
    --Slate-900: rgb(31, 49, 79);
    --Slate-500: rgb(104, 119, 141);
    --Slate-300: rgb(213, 225, 239);
    --White: rgb(255, 255, 255);
        /** Spacing **/
    --spacing-500: 40px;
    --spacing-300: 24px;
    --spacing-200: 16px;
        /** Font Preset 1 **/
    --text-preset-1-font-family: 'Outfit', sans-serif;
    --text-preset-1-font-size: 22px;
    --text-preset-1-line-height: 120%;
    --text-preset-1-letter-spacing: 0px;
    --text-preset-1-font-weight: bold;
        /** Font Preset 2 **/
    --text-preset-2-font-family: 'Outfit', sans-serif;
    --text-preset-2-font-size: 15px;
    --text-preset-2-line-height: 140%;
    --text-preset-2-letter-spacing: 0.2px;
    --text-preset-2-font-weight: normal;
/** Content Start **/
/** Content Main End **/
.text-preset-1 {
    font-family: var(--text-preset-1-font-family);
    font-size: var(--text-preset-1-font-size);
    line-height: var(--text-preset-1-line-height);
    letter-spacing: var(--text-preset-1-letter-spacing);
    font-weight: var(--text-preset-1-font-weight);
    color: var(--Slate-900);
}

.text-preset-2 {
    font-family: var(--text-preset-2-font-family);
    font-size: var(--text-preset-2-font-size);
    line-height: var(--text-preset-2-line-height);
    letter-spacing: var(--text-preset-2-letter-spacing);
    font-weight: var(--text-preset-2-font-weight);
    color: var(--Slate-500);
}

What challenges did you encounter, and how did you overcome them?

My main challenge was adjusting size boxes correctly with flex, margin, and padding. Along with getting colors/background-colors correct, knowing body background color was its color is better to know than just to see where I went wrong elsewhere

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: var(--Slate-300);
}

.frame-main-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 320px;
    height: 499px;
    background-color: var(--White);
    padding: 16px 16px 40px 16px;
    border-radius: 20px;
    overflow: hidden;
    gap: 24px;
}

p {
    text-align: center;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 20px;
    padding: 0 16px;
}

.image-qr-code {
    width: 100%;
    height: 100%;
    margin: 0%;
    padding: 0%;
    border-radius: 10px;
    object-fit: contain;
}

What specific areas of your project would you like help with?

Specifically, not really, but any tips and tricks for both efficiency and learning for alignment/sizing/flexing would be greatly appreciated.