avoid habit browser render bug

// ==UserScript==
// @name avoid habit render bug
// @description 本文途切れバグ回避のためフェードインCSS除去
// @include http*://*

function removeFadeinAnimation() {
    const rulesByAnimation = {};
    const fadeinAnimationsSet = new Set();
    const sheets = document.styleSheets;
    // console.log(sheets);
    function eachRules(rules) {
        Array.from(rules).forEach(rule => {
            const type = rule.type;
            if (type === CSSRule.STYLE_RULE) {
                const animationValue =
                    rule.style.animationName || rule.style.animation;
                if (animationValue) {
                    const animationName = animationValue
                        .split(" ")
                        .slice(-1)[0];
                    // console.log(animationName, cssText, i, j);
                    if (rulesByAnimation[animationName] === undefined)
                        rulesByAnimation[animationName] = [];
                    rulesByAnimation[animationName].push(rule);
                }
            } else if (type === CSSRule.KEYFRAMES_RULE) {
                // console.log(rule);
                const keyRules = rule.rules || rule.cssRules;
                const opacityKFs = Array.from(keyRules)
                    .filter(
                        rule =>
                            rule.type === CSSRule.KEYFRAME_RULE &&
                            rule.style.length === 1 &&
                            rule.style[0] === "opacity"
                    )
                    .reduce((obj, rule) => {
                        obj[rule.keyText] = rule.style.opacity;
                        return obj;
                    }, {});
                if (opacityKFs["0%"] === "0" && opacityKFs["100%"] === "1") {
                    fadeinAnimationsSet.add(rule.name);
                }
            } else if (type === CSSRule.MEDIA_RULE) {
                const rules = rule.rules || rule.cssRules;
                // console.log(rules);
                eachRules(rules);
            }
        });
    }
    Array.from(sheets).forEach(sheet => {
        try {
            const rules = sheet.rules || sheet.cssRules;
            eachRules(rules);
        } catch (error) {
            console.log(error);
        }
    });
    const fadeinAnimations = Array.from(fadeinAnimationsSet.values());
    const fadeinRules = Object.keys(rulesByAnimation)
        .filter(a => fadeinAnimations.includes(a))
        .map(a => rulesByAnimation[a])
        .reduce((arr, val) => arr.concat(val), []);
    // console.log(fadeinRules, fadeinAnimations);

    // フェードインするアニメーションのCSSルールを除去
    fadeinRules.forEach(fadeinRule => {
        const rule = fadeinRule;
        // console.log(rule);
        rule.style.animation = "none";
        rule.style.animationName = "none";
        rule.style.cssText += "opacity: 1 !important;";
    });
}

window.addEventListener("load", removeFadeinAnimation);
removeFadeinAnimation();