* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    /* 去掉移动端的点击高亮（iOS/Android） */
    -webkit-tap-highlight-color: transparent;
}

/* 全局平滑滚动 */
html {
    scroll-behavior: smooth;
}

/* 清除a的下划线和点击色 */
a {
    text-decoration: none;
    color: unset;
}

/* 鼠标悬停时显示手形光标 */
.clickable {
    cursor: pointer;
}

/* 基础交互元素默认不显示边框outline */
a,
.clickable,
button,
input,
textarea,
select {
    outline: none;
    -webkit-tap-highlight-color: transparent;
    background-clip: padding-box;
}

/* 亮色模式下的无障碍焦点边框outline样式 */
a:focus-visible,
.clickable:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
    outline: 2px solid #2684FF;
    /* Google 常用的蓝色 */
    outline-offset: 2px;
}

h2,
h3 {
    line-height: 1.4;
}

p {
    line-height: 1.6;
}

span.emoji {
    font-size: 1.3em;
    vertical-align: middle;
}

/* 深色模式下的无障碍焦点边框outline样式 */
@media (prefers-color-scheme: dark) {

    a:focus-visible,
    .clickable:focus-visible,
    button:focus-visible,
    input:focus-visible,
    textarea:focus-visible,
    select:focus-visible {
        outline: 2px solid #8AB4F8;
        /* Google Material 的浅蓝色 */
    }
}

/* === 页面基础 === */
body {
    margin: 0;
    padding-top: 125px;
    padding-bottom: 5px;
    background: var(--bg);
    color: var(--fg);
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

main {
    padding: 25px 15px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 25px;
    opacity: 0;
    transform: translateY(20px);
    animation: main-fade-in 0.8s ease-out forwards;
}

section {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    /* 锚点定位时，预留导航栏高度 */
    scroll-margin-top: 125px;
}

@keyframes main-fade-in {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 按钮样式 */
button,
.btn {
    font-family: inherit;
    font-size: 16px;
    padding: 8px 16px;
    border: 1px solid color-mix(in oklab, var(--bg) 60%, #999 18%);
    border-radius: 9999px;
    background: color-mix(in oklab, var(--bg) 40%, transparent);
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover,
.btn:hover {
    color: var(--link);
    background: color-mix(in oklab, var(--bg) 88%, transparent);
    border-color: color-mix(in oklab, var(--bg) 58%, var(--link) 22%);
}

/* === 导航栏 === */
.nav-wrap {
    position: fixed;
    top: 12px;
    left: 50%;
    transform: translateX(-50%);
    width: 96vw;
    z-index: 10;
    pointer-events: none;
}

.nav {
    position: relative;
    display: flex;
    align-items: center;
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    background: var(--glass-bg);
    border: 1px solid var(--glass-brd);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 15px 24px;
    pointer-events: auto;
}

/* 左侧 文字Logo，两行 */
.brand {
    text-decoration: none;
    color: var(--fg);
    line-height: 1.2;
    padding: 9px 15px;
    border-radius: 14px;
    border: 1px solid transparent;
    transition: background .3s ease;
}

.brand:hover {
    background: color-mix(in oklab, var(--bg) 50%, transparent);
    border-color: color-mix(in oklab, var(--bg) 60%, #999 18%);
}

.brand-line1 {
    display: block;
    font-size: 20px;
    font-weight: 600;
}

.brand-line2 {
    display: block;
    font-size: 14px;
    opacity: .85;
    margin-top: 2px;
}

/* 中央菜单 */
.menu {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    gap: 60px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.link {
    display: inline-flex;
    align-items: center;
    height: 48px;
    padding: 28px 36px;
    border-radius: 999px;
    border: 1px solid transparent;
    font-size: 20px;
    word-spacing: 0.5em;
    color: var(--fg);
    text-decoration: none;
    background: var(--glass-bg);
    transition: background .3s ease, border-color .3s ease, transform .2s ease;
}

.link:hover {
    background: color-mix(in oklab, var(--bg) 40%, transparent);
    border-color: color-mix(in oklab, var(--bg) 60%, #999 18%);
}

.link:active {
    transform: translateY(1px);
}

.link.active {
    color: var(--link);
    background: color-mix(in oklab, var(--bg) 88%, transparent);
    border-color: color-mix(in oklab, var(--bg) 58%, var(--link) 22%);
}

/* 右侧 图片Logo */
.nav img {
    width: 75px;
    height: 75px;
    margin-left: auto;
    border-radius: 50%;
    opacity: 0.7;
}

.dark-logo {
    display: none;
}

@media (prefers-color-scheme: dark) {
    .light-logo {
        display: none;
    }

    .dark-logo {
        display: inline-block;
    }
}

/* section里的内容卡片 */
section div.card {
    width: 95%;
    max-width: 800px;
}

/* ===卡片网格卡片（悬停缩放卡片）样式=== */
.card-grid {
    width: 95%;
    padding-inline: 3%;
    display: grid;
    gap: 24px;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    justify-items: center;
}

.card-grid .card {
    padding: 24px 18px;
    border-radius: 80px;
    margin-block: 30px;
    height: 180px;
    width: 220px;
    justify-content: center;
}

.card-grid .card p {
    display: none;
}

.card-grid .card:hover {
    border-radius: var(--radius);
    margin-block: 10px;
    height: 220px;
    width: 320px;
    max-width: 100vw;
    justify-content: flex-start;
}

.card-grid .card:hover p {
    display: inline-block;
}

.card-grid .card:hover .btn {
    position: absolute;
    bottom: 20px;
    right: 30px;
}

/* === 卡片flex卡片样式=== */
.card-flex {
    width: 95%;
    padding-inline: 3%;
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
    justify-content: center;
}

.card-flex .card {
    padding: 24px 18px;
    height: 210px;
    width: 310px;
    justify-content: flex-start;
}

.card-flex .btn {
    position: absolute;
    bottom: 24px;
}

/* ===卡片横向滚动flex网格卡片（悬停缩放卡片）样式=== */
.card-flex-grid {
    width: 88%;
    padding-inline: 30px;
    display: flex;
    gap: 24px;
    flex-wrap: nowrap;
    overflow-x: auto;
    /* 隐藏默认滚动条 */
    scrollbar-width: none;
    /* Firefox */
    -ms-overflow-style: none;
    /* IE/Edge */
    -webkit-overflow-scrolling: touch;
}

/* 隐藏默认滚动条 */
.card-flex-grid::-webkit-scrollbar {
    display: none;
    /* Chrome/Safari */
}

.card-flex-grid .card {
    padding: 30px 18px;
    border-radius: 80px;
    margin: 28px 0;
    height: 180px;
    width: 220px;
    flex: 0 0 auto;
    /* 防止卡片缩小 */
    justify-content: center;
}

.card-flex-grid .card p {
    display: none;
}

.card-flex-grid .card:hover {
    border-radius: var(--radius);
    margin: 8px 0;
    height: 220px;
    width: 320px;
    max-width: 100vw;
    justify-content: flex-start;
}

.card-flex-grid .card:hover p {
    display: inline-block;
}

.card-flex-grid .card:hover .btn {
    display: inline-block;
    position: absolute;
    bottom: 20px;
    right: 30px;
}

/* === 页脚 === */
footer.card {
    width: 96vw;
    margin: 0 auto;
    margin-top: 40px;
    margin-bottom: 20px;
    padding-block: 40px;
    text-align: center;
}

.github-repository img {
    width: 40px;
    height: 40px;
    padding: 8px;
    vertical-align: middle;
    background-color: #181717;
    border-radius: 6px;
    transition: filter 0.3s;
}

.github-repository:hover {
    filter: brightness(1.8);
    /* 整体亮一些 */
}

/* 用户系统设置了“减少动画/动效”时禁用 */
@media (prefers-reduced-motion: reduce) {
    * {
        animation: none !important;
        transition: none !important;
        scroll-behavior: auto !important;
    }

    /* 让 main 在禁用动画时直接显示最终状态 */
    main {
        opacity: 1 !important;
        transform: none !important;
    }
}