SanYeCao-blog/src/components/FloatingActions.astro

<div class="floating-actions">
    <button
        id="theme-toggle-fab"
        aria-label="Toggle theme"
        title="Toggle theme"
    >
        <svg
            class="theme-toggle-icon"
            viewBox="0 0 24 24"
            width="20"
            height="20"
            aria-hidden="true"
        >
            <path
                class="sun"
                fill-rule="evenodd"
                d="M12 17.5a5.5 5.5 0 1 0 0-11 5.5 5.5 0 0 0 0 11zm0 1.5a7 7 0 1 0 0-14 7 7 0 0 0 0 14zm12-7a.8.8 0 0 1-.8.8h-2.4a.8.8 0 0 1 0-1.6h2.4a.8.8 0 0 1 .8.8zM4 12a.8.8 0 0 1-.8.8H.8a.8.8 0 0 1 0-1.6h2.5a.8.8 0 0 1 .8.8zm16.5-8.5a.8.8 0 0 1 0 1l-1.8 1.8a.8.8 0 0 1-1-1l1.7-1.8a.8.8 0 0 1 1 0zM6.3 17.7a.8.8 0 0 1 0 1l-1.7 1.8a.8.8 0 1 1-1-1l1.7-1.8a.8.8 0 0 1 1 0zM12 0a.8.8 0 0 1 .8.8v2.5a.8.8 0 0 1-1.6 0V.8A.8.8 0 0 1 12 0zm0 20a.8.8 0 0 1 .8.8v2.4a.8.8 0 0 1-1.6 0v-2.4a.8.8 0 0 1 .8-.8zM3.5 3.5a.8.8 0 0 1 1 0l1.8 1.8a.8.8 0 1 1-1 1L3.5 4.6a.8.8 0 0 1 0-1zm14.2 14.2a.8.8 0 0 1 1 0l1.8 1.7a.8.8 0 0 1-1 1l-1.8-1.7a.8.8 0 0 1 0-1z"
            ></path>
            <path
                class="moon"
                fill-rule="evenodd"
                d="M16.5 6A10.5 10.5 0 0 1 4.7 16.4 8.5 8.5 0 1 0 16.4 4.7l.1 1.3zm-1.7-2a9 9 0 0 1 .2 2 9 9 0 0 1-11 8.8 9.4 9.4 0 0 1-.8-.3c-.4 0-.8.3-.7.7a10 10 0 0 0 .3.8 10 10 0 0 0 9.2 6 10 10 0 0 0 4-19.2 9.7 9.7 0 0 0-.9-.3c-.3-.1-.7.3-.6.7a9 9 0 0 1 .3.8z"
            ></path>
        </svg>
    </button>

    <button id="back-to-top" aria-label="Back to top" title="Back to top">
        <svg
            viewBox="0 0 24 24"
            width="20"
            height="20"
            fill="none"
            stroke="currentColor"
            stroke-width="2.2"
            stroke-linecap="round"
            stroke-linejoin="round"
            aria-hidden="true"
        >
            <path d="M18 15l-6-6-6 6"></path>
        </svg>
    </button>
</div>

<style>
    .floating-actions {
        position: fixed;
        right: 1.25rem;
        bottom: 1.25rem;
        display: flex;
        flex-direction: column;
        gap: 0.75rem;
        z-index: 1000;
    }

    #theme-toggle-fab,
    #back-to-top {
        width: 3rem;
        height: 3rem;
        border: #a7a7a7 1.5px solid;
        border-radius: 999px;
        background: rgba(255, 255, 255, 0.92);
        color: #222;
        /* box-shadow: 0 4px 14px rgba(0, 0, 0, 0.16); */
        cursor: pointer;
        display: flex;
        align-items: center;
        justify-content: center;
        backdrop-filter: blur(6px);
    }

    #theme-toggle-fab {
        position: relative;
    }

    #theme-toggle-fab {
        position: relative;
    }

    .theme-toggle-icon {
        width: 1.2rem;
        height: 1.2rem;
        fill: currentColor;
    }

    .theme-toggle-icon .sun,
    .theme-toggle-icon .moon {
        transform-origin: center;
        transition:
            opacity 0.2s ease,
            transform 0.2s ease;
    }

    .theme-toggle-icon .sun {
        opacity: 1;
        transform: scale(1) rotate(0deg);
    }

    .theme-toggle-icon .moon {
        opacity: 0;
        transform: scale(0.75) rotate(-20deg);
    }

    :global(.dark) .theme-toggle-icon .sun {
        opacity: 0;
        transform: scale(0.75) rotate(20deg);
    }

    :global(.dark) .theme-toggle-icon .moon {
        opacity: 1;
        transform: scale(1) rotate(0deg);
    }

    #theme-toggle-fab,
    #back-to-top {
        /* opacity: 0; */
        visibility: hidden;
        transform: translateY(150px);
        transition:
            opacity 0.2s ease,
            transform 0.27s ease,
            visibility 0.2s ease;
    }

    #theme-toggle-fab.show,
    #back-to-top.show {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
    }

    #theme-toggle-fab.show:hover,
    #back-to-top.show:hover {
        transform: translateY(-2px);
    }

    :global(.dark) #theme-toggle-fab,
    :global(.dark) #back-to-top {
        background: rgba(34, 34, 34, 0.92);
        color: #f5f5f5;
        box-shadow: 0 4px 14px rgba(0, 0, 0, 0.32);
        border: #515151 2px solid;
    }

    @media (max-width: 640px) {
        .floating-actions {
            right: 1rem;
            bottom: 1rem;
            gap: 0.65rem;
        }

        #theme-toggle-fab,
        #back-to-top {
            width: 2.75rem;
            height: 2.75rem;
        }
    }
</style>

<script>
    const initFloatingActions = () => {
        const backToTop = document.getElementById("back-to-top");
        const themeToggle = document.getElementById("theme-toggle-fab");

        if (backToTop && backToTop.dataset.bound !== "true") {
            const toggleBackToTop = () => {
                if (window.scrollY > 300) {
                    backToTop.classList.add("show");
                } else {
                    backToTop.classList.remove("show");
                }
            };

            backToTop.addEventListener("click", () => {
                window.scrollTo({
                    top: 0,
                    behavior: "smooth",
                });
            });

            window.addEventListener("scroll", toggleBackToTop, {
                passive: true,
            });
            toggleBackToTop();
            backToTop.dataset.bound = "true";
        }

        if (themeToggle && themeToggle.dataset.bound !== "true") {
            const togglethemeToggle = () => {
                if (window.scrollY > 300) {
                    themeToggle.classList.add("show");
                } else {
                    themeToggle.classList.remove("show");
                }
            };

            const root = document.documentElement;

            const applyTheme = (theme: string) => {
                if (theme === "dark") {
                    root.classList.add("dark");
                    localStorage.setItem("color-theme", "dark");
                } else {
                    root.classList.remove("dark");
                    localStorage.setItem("color-theme", "light");
                }
            };

            themeToggle.addEventListener("click", () => {
                const isDark = root.classList.contains("dark");
                applyTheme(isDark ? "light" : "dark");
            });

            window.addEventListener("scroll", togglethemeToggle, {
                passive: true,
            });

            togglethemeToggle();
            themeToggle.dataset.bound = "true";
        }
    };

    initFloatingActions();
    document.addEventListener("astro:page-load", initFloatingActions);
</script>