Html – How do I make bold headlines turn italic on hover using CSS?

I’m actually not a coder in any level, just trying to do my own website.

I found some codes to create a marquee effect. But i decided that it will be enough to me if i remove offset value from codes.

So, i just want my "bold headlines" turn to "italic" style when i hover them. And also i want to keep pics with hover on. But when i try to delete or change some lines, the offset value keeps sliding. I mean, when i hover on headline, i see multiple headlines next to that one in italic style.

I guess some lines of this code is unnecessary but here is the CSS:

*,
*::after,
*::before {
    box-sizing: border-box;
}

:root {
    font-size: 15px;
}

body {
    margin: 0;
    --color-text: #000000;
    --color-bg: #000000;
    --color-link: #000000;
    --color-link-hover: #000000;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-family: sofia-pro, sans-serif;
}

a {
    text-decoration: none;
    color: var(--color-link);
    outline: #cec7ff;
}

a:hover,
a:focus {
    color: var(--color-link-hover);
    outline: none;
}

.menu {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    padding: 10vh 0 25vh;
    --marquee-width: 100vw;
    --offset: 20vw;
    --move-initial: calc(-25% + var(--offset));
    --move-final: calc(-50% + var(--offset));
    --item-font-size: 5vw;
    counter-reset: menu;
}

.menu__item {
    cursor: default;
    position: relative;
    padding: 0 5vw;
}

.menu__item-link {
    display: inline-block;
    cursor: pointer;
    position: relative;
    -webkit-text-stroke: 0px #000;
    text-stroke: 0px #000;
    -webkit-text-fill-color: #000000;
    text-fill-color: transparent;
    color: transparent;
    transition: opacity 0.4s;
}

.menu__item-link:hover {
    transition-duration: 0.1s;
    opacity: 0;
}

.menu__item-img {
    pointer-events: none;
    position: absolute;
    height: 30vh;
    max-height: 400px;
    opacity: 0;
    left: 120%;
    top: 50%;
    transform: translate3d(calc(-100% - 6vw),-30%,0) translate3d(0,10px,0);
}

.menu__item-link:hover + .menu__item-img {
    opacity: 1;
    transform: translate3d(calc(-100% - 6vw),-30%,0) rotate3d(0,0,0,0deg);
    transition: all 0.2s;
}

/* Make sure 3 items are visible in the viewport by setting suitable font size. */

.marquee {
    position: absolute;
    top: 0;
    left: 0;
    width: var(--marquee-width);
    overflow: hidden;
    pointer-events: none;
    mix-blend-mode: color-burn;
}

.marquee__inner {
    width: fit-content;
    display: flex;
    position: relative;
    transform: translate3d(var(--move-initial), 0, 0);
    animation: marquee 6s linear infinite;
    animation-play-state: paused;
    opacity: 0;
    transition: opacity 0.1s;
}

.menu__item-link:hover ~ .marquee .marquee__inner {
    animation-play-state: running;
    opacity: 1;
    transition-duration: 0.4s;
}

.marquee span {
    text-align: center;

}

.menu__item-link,
.marquee span {
    white-space: nowrap;
    font-size: var(--item-font-size);
    padding: 0 1vw;
    font-weight: 900;
    line-height: 1.15;
}

.marquee span {
    font-style: italic;
}

@keyframes marquee {
    0% {
        transform: translate3d(var(--move-initial), 0, 0);
    }

    100% {
        transform: translate3d(var(--move-final), 0, 0);
    }
}

@media screen and (min-width: 53em) {
    .frame {
        text-align: left;
        display: grid;
        align-content: space-between;
        width: 100%;
        padding: 2.5rem 6vw;
        pointer-events: none;
        grid-template-columns: 75% 25%;
        grid-template-rows: auto;
    }
  }