/* ==========================================================================
   首页（暗色主题）
   本文件只做「主题映射 + 页面组件」，颜色一律取自 tokens.css。
   ========================================================================== */

:root {
    /* 暗色主题语义映射 */
    --bg:              #0a0a0a;
    --surface:         #141414;
    --surface-hover:   #1e1e1e;
    --border:          #222;
    --border-hover:    #444;
    --text:            #f0f0f0;
    --text-secondary:  #999;
    --text-on-brand:   #000;

    --accent:          var(--brand);
    --accent-hover:    var(--brand-hover);
    --accent-2:        #ff6b6b;

    --radius:          var(--radius-lg);
}

body {
    background: var(--bg);
    color: var(--text);
}

/* 懒加载占位色在暗色主题下需反转 */
img[loading="lazy"] {
    background-color: var(--surface);
}

/* ── Header / Nav ── */
header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(10, 10, 10, .85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: transform .3s var(--ease), background-color .3s var(--ease),
                box-shadow .3s var(--ease);
}

header.is-scrolled {
    background: rgba(10, 10, 10, .95);
    box-shadow: 0 4px 20px rgba(0, 0, 0, .35);
}

nav {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 var(--space-6);
    height: var(--header-h);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    text-decoration: none;
    color: var(--text);
    font-weight: 700;
    font-size: 20px;
    letter-spacing: -.5px;
}

.logo-area img {
    height: 34px;
    width: auto;
}

.nav-links {
    display: flex;
    gap: var(--space-8);
    list-style: none;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: color .2s var(--ease);
}

.nav-links a:hover {
    color: var(--text);
}

/* ── Hamburger Menu ── */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: var(--space-2);
    z-index: 101;
    background: none;
    border: none;
    -webkit-tap-highlight-color: transparent;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: transform .3s var(--ease), opacity .3s var(--ease);
}

.hamburger.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

.mobile-nav-overlay {
    position: fixed;
    inset: 0;
    top: var(--header-h);
    background: var(--bg);
    z-index: 99;
    padding: var(--space-8) var(--space-6);
    flex-direction: column;
    gap: var(--space-2);
    opacity: 0;
    visibility: hidden;
    transform: translateX(24px);
    transition: opacity .3s var(--ease), transform .32s var(--ease),
                visibility 0s linear .32s;
    will-change: transform, opacity;
    -webkit-tap-highlight-color: transparent;
}

.mobile-nav-overlay.active {
    opacity: 1;
    visibility: visible;
    transform: translateX(0);
    transition: opacity .3s var(--ease), transform .32s var(--ease),
                visibility 0s;
}

.mobile-nav-overlay a {
    display: block;
    color: var(--text);
    text-decoration: none;
    font-size: 18px;
    font-weight: 600;
    padding: var(--space-4) var(--space-5);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    opacity: 0;
    transform: translateX(16px);
    transition: background .2s var(--ease), opacity .34s var(--ease),
                transform .34s var(--ease);
    -webkit-tap-highlight-color: transparent;
}

.mobile-nav-overlay.active a {
    opacity: 1;
    transform: translateX(0);
}

.mobile-nav-overlay.active a:nth-child(1) { transition-delay: .06s; }
.mobile-nav-overlay.active a:nth-child(2) { transition-delay: .12s; }
.mobile-nav-overlay.active a:nth-child(3) { transition-delay: .18s; }
.mobile-nav-overlay.active a:nth-child(4) { transition-delay: .24s; }

.mobile-nav-overlay a:hover,
.mobile-nav-overlay a:active {
    background: var(--surface);
}

/* ── 滚动进度条（顶部细条，由 reveal.js 驱动 scaleX） ── */
.scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--accent);
    transform: scaleX(0);
    transform-origin: left center;
    z-index: 1000;
    pointer-events: none;
    will-change: transform;
}

/* ══ 首屏加载编排（B）═══════════════════════════════════════════
   首屏元素不再等滚动触发（原 .reveal 已移除），改由 html.is-ready 驱动：
   徽章淡入 → 标题逐行幕布揭示 → 副标题上浮 → 按钮编排 → 图片柔光浮现。
   全部用 html.js 门控：脚本没跑起来时元素照常显示，绝不白屏。 */

@keyframes hero-fade-in {
    from { opacity: 0; }
    to   { opacity: 1; }
}

@keyframes hero-line-up {
    from { transform: translateY(110%); }
    to   { transform: translateY(0); }
}

@keyframes hero-curtain-up {
    from { clip-path: inset(100% 0 0 0); opacity: 0; }
    /* 负值收尾：避免 clip-path 裁掉按钮的 focus 描边 */
    to   { clip-path: inset(-24px -24px -24px -24px); opacity: 1; }
}

@keyframes hero-rise {
    from { opacity: 0; transform: translateY(14px); }
    to   { opacity: 1; transform: none; }
}

/* 逐行揭示：行容器裁切，内部文字从下方滑入 */
.hero-line {
    display: block;
    overflow: hidden;
    padding-bottom: .09em;
    margin-bottom: -.09em;
}

.hero-line > span {
    display: block;
}

html.is-ready .hero-badge {
    animation: hero-fade-in .5s var(--ease-out) .05s both;
}

html.is-ready .hero-line > span {
    animation: hero-line-up .72s var(--ease-out-back) both;
}

html.is-ready .hero-line:nth-child(1) > span { animation-delay: .12s; }
html.is-ready .hero-line:nth-child(2) > span { animation-delay: .24s; }

html.is-ready .hero-sub {
    animation: hero-curtain-up .6s var(--ease-out) .38s both;
}

html.is-ready .hero-actions {
    animation: hero-rise .55s var(--ease-out) .48s both;
}

html.is-ready .hero-img {
    animation: hero-rise .7s var(--ease-out) .3s both;
}

/* ══ 骨架屏（D）═════════════════════════════════════════════════
   页面未就绪时首屏显示骨架占位，is-ready 后由编排动画接管。
   页面若在 200ms 内就绪，骨架几乎不可见，不会拖慢感知。 */
html.js:not(.is-ready) .hero-badge,
html.js:not(.is-ready) .hero-title,
html.js:not(.is-ready) .hero-hl,
html.js:not(.is-ready) .hero-sub,
html.js:not(.is-ready) .hero-actions,
html.js:not(.is-ready) .hero-img {
    color: transparent !important;
    background-image: linear-gradient(90deg,
        transparent 0%, rgba(255, 255, 255, .08) 50%, transparent 100%);
    background-size: 200% 100%;
    animation: skeleton-shimmer 1.4s linear infinite;
}

html.js:not(.is-ready) .hero-badge,
html.js:not(.is-ready) .hero-line > span,
html.js:not(.is-ready) .hero-sub,
html.js:not(.is-ready) .hero-actions,
html.js:not(.is-ready) .hero-img {
    background-color: var(--surface);
}

html.js:not(.is-ready) .hero-badge   { border-radius: var(--radius-pill); }
html.js:not(.is-ready) .hero-line > span { border-radius: var(--radius-sm); }
html.js:not(.is-ready) .hero-sub     { border-radius: var(--radius-sm); max-width: 420px; }
html.js:not(.is-ready) .hero-actions { border-radius: var(--radius-md); max-width: 300px; height: 54px; }
html.js:not(.is-ready) .hero-img     { border-radius: var(--radius-lg); min-height: 240px; }

html.js:not(.is-ready) .hero-actions .btn,
html.js:not(.is-ready) .hero-img img {
    visibility: hidden;
}

/* 首屏图：就绪前模糊占位，加载完淡入清晰 */
html.js .hero-img img {
    transition: filter .6s var(--ease);
}

html.js .hero-img img:not(.is-loaded) {
    filter: blur(12px);
}

/* ══ 顶部加载进度条（B）════════════════════════════════════════ */
.load-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, var(--accent), var(--brand-hover));
    transform: scaleX(0);
    transform-origin: left center;
    z-index: 1001;
    pointer-events: none;
    will-change: transform;
}

/* 未就绪时缓慢推进到七成，就绪后补满并淡出 */
html.js:not(.is-ready) .load-progress {
    transform: scaleX(.7);
    transition: transform 2.4s var(--ease-out);
}

html.is-ready .load-progress {
    transform: scaleX(1);
    transition: transform .28s var(--ease-out), opacity .3s var(--ease) .28s;
}

.load-progress.is-done {
    opacity: 0;
}

/* ── Hero ── */
.hero {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 100px var(--space-6) 80px;
    display: flex;
    align-items: center;
    gap: 80px;
    position: relative;
}

/* 环境光晕：缓慢漂移的品牌色柔光，制造深度感 */
.hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(58% 48% at 72% 28%, var(--brand-glow) 0%, transparent 70%);
    opacity: .35;
    pointer-events: none;
}

/* 第二层光晕：位置更低、反向且更慢，与第一层交错形成流动感 */
.hero::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(52% 42% at 22% 72%,
                var(--brand-glow-soft) 0%, transparent 68%);
    opacity: .5;
    pointer-events: none;
}

.hero-text,
.hero-img {
    position: relative;
    z-index: 1;
}

@media (prefers-reduced-motion: no-preference) {
    .hero::before {
        animation: hero-glow-drift 18s var(--ease) infinite alternate;
    }

    .hero::after {
        animation: hero-glow-drift-b 26s var(--ease) infinite alternate;
    }

    @keyframes hero-glow-drift {
        from { transform: translate3d(-2%, -1%, 0) scale(1); opacity: .28; }
        to   { transform: translate3d(2%, 2%, 0) scale(1.08); opacity: .45; }
    }

    @keyframes hero-glow-drift-b {
        from { transform: translate3d(3%, 2%, 0) scale(1.05); opacity: .35; }
        to   { transform: translate3d(-3%, -2%, 0) scale(.95); opacity: .6; }
    }
}

.hero-text {
    flex: 1;
    min-width: 0;
}

.hero-badge {
    display: inline-block;
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--accent);
    font-size: 13px;
    font-weight: 600;
    padding: 6px 14px;
    border-radius: var(--radius-pill);
    margin-bottom: var(--space-6);
    letter-spacing: .5px;
}

.hero h1 {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -1.5px;
    margin-bottom: var(--space-5);
}

.hero h1 .hero-hl {
    color: var(--accent);
}

.hero p {
    color: var(--text-secondary);
    font-size: 18px;
    max-width: 460px;
    margin-bottom: 36px;
}

.hero-actions {
    display: flex;
    gap: var(--space-4);
    flex-wrap: wrap;
}

.hero-img {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-img img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: 14px 28px;
    font-size: 16px;
    font-weight: 600;
    border-radius: var(--radius);
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: background-color .2s var(--ease), border-color .2s var(--ease),
                transform .15s var(--ease), color .2s var(--ease);
    letter-spacing: -.3px;
    position: relative;
    overflow: hidden;
    -webkit-tap-highlight-color: transparent;
}

.btn-primary {
    background: var(--accent);
    color: var(--text-on-brand);
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

/* ⑥ 按钮悬停：高光扫过 + 下载箭头向下轻跳 */
.btn-primary::before {
    content: "";
    position: absolute;
    top: 0;
    left: -60%;
    width: 45%;
    height: 100%;
    background: linear-gradient(100deg, transparent,
                rgba(255, 255, 255, .18), transparent);
    transform: skewX(-18deg);
    pointer-events: none;
}

.btn-primary:hover::before {
    animation: btn-sheen .6s var(--ease);
}

.download-card .btn-primary:hover svg {
    animation: btn-arrow-nudge .5s var(--ease);
}

.btn-outline {
    background: transparent;
    color: var(--text);
    border: 1.5px solid var(--border);
}

.btn-outline:hover {
    border-color: var(--text-secondary);
    background: var(--surface);
}

.btn-large {
    padding: var(--space-4) 36px;
    font-size: 17px;
}

.btn svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

/* 触摸/点击反馈：按压回弹 + 中心水波纹（纯 CSS，零 JS） */
.btn:active {
    transform: scale(.96);
}

.btn::after {
    content: "";
    position: absolute;
    inset: 0;
    border-radius: inherit;
    background: radial-gradient(circle at center,
                rgba(255, 255, 255, .4) 0%,
                rgba(255, 255, 255, 0) 60%);
    opacity: 0;
    transform: scale(.3);
    transition: opacity .5s var(--ease), transform .5s var(--ease);
    pointer-events: none;
}

.btn:active::after {
    opacity: 1;
    transform: scale(1.8);
    transition: 0s;
}

/* ── Section ── */
section {
    padding: 100px var(--space-6);
}

.section-header {
    text-align: center;
    max-width: 600px;
    margin: 0 auto var(--space-16);
}

.section-tag {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    color: var(--accent);
    letter-spacing: 1px;
    text-transform: uppercase;
    margin-bottom: var(--space-3);
}

.section-header h2 {
    font-size: 40px;
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: var(--space-3);
}

.section-header p {
    color: var(--text-secondary);
    font-size: 17px;
}

/* ── Download Section ── */
#download {
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    position: relative;
    overflow: hidden;
}

.download-grid {
    max-width: var(--max-w);
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-5);
}

.download-card {
    background-color: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px 28px;
    text-align: center;
    transition: border-color .25s var(--ease), transform .18s var(--ease),
                box-shadow .45s var(--ease), opacity .25s var(--ease);
    -webkit-tap-highlight-color: transparent;
    position: relative;
}

/* ③ 指针高光：柔光跟随鼠标（仅指针设备，触屏不触发） */
.download-card::before {
    content: "";
    position: absolute;
    inset: 0;
    border-radius: inherit;
    background: radial-gradient(260px circle at var(--mx, 50%) var(--my, 0%),
                var(--brand-glow), transparent 70%);
    opacity: 0;
    transition: opacity .35s var(--ease);
    pointer-events: none;
}

@media (hover: hover) and (pointer: fine) {
    .download-card:hover::before {
        opacity: 1;
    }
}

.download-card:active {
    transform: scale(.98);
}

/* 下载卡同样错峰 */
.download-grid > .reveal:nth-child(1) { --reveal-delay: .04s; }
.download-grid > .reveal:nth-child(2) { --reveal-delay: .10s; }
.download-grid > .reveal:nth-child(3) { --reveal-delay: .16s; }

.download-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-4px);
}

.download-card .platform-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto var(--space-5);
    background: var(--surface);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
}

.download-card .platform-icon svg {
    width: 28px;
    height: 28px;
}

.download-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 6px;
}

.download-card .version {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: var(--space-2);
}

.download-card .size {
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: var(--space-6);
    opacity: .7;
}

/* 暂未开放的平台：不可点击，整卡灰化 */
.download-card--disabled {
    opacity: .65;
}

/* ⑦ 待开放卡：悬停微提亮，不再像两张废卡 */
.download-card--disabled:hover {
    border-color: var(--border-hover);
    opacity: .85;
    transform: none;
}

.download-card--disabled:active {
    transform: none;
}

.btn-disabled {
    background: var(--surface);
    color: var(--text-secondary);
    border: 1.5px solid var(--border);
    cursor: not-allowed;
}

.download-card .btn {
    width: 100%;
    justify-content: center;
}

/* ② 流光边框：光带沿卡片边缘缓慢扫过（需 @property 支持，不支持时静态显示） */
@property --card-angle {
    syntax: '<angle>';
    inherits: false;
    initial-value: 0deg;
}

@keyframes card-border-flow {
    to { --card-angle: 360deg; }
}

@keyframes badge-breathe {
    0%, 100% { box-shadow: 0 0 0 0 var(--brand-glow); }
    50%      { box-shadow: 0 0 0 6px transparent; }
}

/* ④⑤ 卡内入场编排：图标弹入 → 文案依次上浮 → 按钮淡入 */
@keyframes card-icon-pop {
    from { opacity: 0; transform: scale(.6); }
    to   { opacity: 1; transform: scale(1); }
}

@keyframes card-item-up {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: none; }
}

@keyframes card-fade-in {
    from { opacity: 0; }
    to   { opacity: 1; }
}

/* ⑥ 下载箭头悬停向下轻跳 */
@keyframes btn-arrow-nudge {
    0%, 100% { transform: translateY(0); }
    45%      { transform: translateY(3px); }
}

/* ⑥ 按钮悬停：一道高光扫过 */
@keyframes btn-sheen {
    from { left: -60%; }
    to   { left: 115%; }
}

/* ① 环境光晕：品牌色自卡片上方透出，进场后点亮投影 */
.download-card.featured {
    border-color: var(--accent);
    position: relative;
    background-image: radial-gradient(130% 90% at 50% -20%,
                      var(--brand-glow-soft), transparent 62%);
}

.download-card.featured.is-visible {
    box-shadow: 0 16px 44px -12px var(--brand-glow);
}

/* ── 下载卡流光边框：单色品牌光带沿卡边旋转（三张卡统一）── */
.download-card::after {
    content: "";
    position: absolute;
    inset: -1px;
    border-radius: inherit;
    padding: 1px;
    background: conic-gradient(from var(--card-angle),
                transparent 0deg,
                var(--brand-glow-soft) 16deg,
                var(--brand-glow-mid) 34deg,
                var(--accent) 44deg,
                var(--brand-glow-mid) 54deg,
                var(--brand-glow-soft) 78deg,
                transparent 132deg,
                transparent 360deg);
    -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
    -webkit-mask-composite: xor;
    mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
    mask-composite: exclude;
    animation: card-border-flow 6s linear infinite;
    pointer-events: none;
}

/* 徽章改为真实 DOM（伪元素已让位给高光/流光），带微呼吸 */
.download-badge {
    position: absolute;
    top: var(--space-3);
    right: var(--space-3);
    background: var(--accent);
    color: var(--text-on-brand);
    font-size: 11px;
    font-weight: 700;
    padding: 3px 10px;
    border-radius: var(--radius-pill);
    animation: badge-breathe 3.2s var(--ease) infinite;
}

/* 徽标语义色：高速=品牌绿（默认）/稳定=冰蓝/备用=灰降级 */
.download-badge.badge-stable {
    background: var(--info);
    color: var(--gray-0);
}
.download-badge.badge-backup {
    background: var(--gray-800);
    color: var(--gray-300);
    border: 1px solid var(--gray-700);
    animation: none;
}

/* ④⑤ 卡内元素错峰入场：图标弹入 → 标题/版本/说明上浮 → 按钮淡入。
   html.js 门控：脚本未执行时元素保持可见，绝不白屏。 */

html.js .download-card .platform-icon,
html.js .download-card h3,
html.js .download-card .version,
html.js .download-card .size,
html.js .download-card .btn {
    opacity: 0;
}

html.js .download-card.is-lit .platform-icon {
    animation: card-icon-pop .55s var(--ease-out-back) .08s both;
}

html.js .download-card.is-lit h3 {
    animation: card-item-up .45s var(--ease-out) .18s both;
}

html.js .download-card.is-lit .version {
    animation: card-item-up .45s var(--ease-out) .26s both;
}

html.js .download-card.is-lit .size {
    animation: card-item-up .45s var(--ease-out) .34s both;
}

html.js .download-card.is-lit .btn {
    animation: card-fade-in .5s var(--ease-out) .42s both;
}

/* 兜底：只要卡片已进入视口（.is-visible），内容就必须可见。
   用于 --p 光束驱动失效 / IO 回调丢失 / 点火阈值够不到时兜住可读性。
   放在隐藏规则之后：特异性更高（多一个 .is-visible），文档顺序也更靠后，双重保险。
   .is-lit 的 animation 优先级高于普通声明，入场动画不受这条影响。 */
html.js .download-card.is-visible .platform-icon,
html.js .download-card.is-visible h3,
html.js .download-card.is-visible .version,
html.js .download-card.is-visible .size,
html.js .download-card.is-visible .btn {
    opacity: 1;
}

/* ══════════════════════════════════════════════════════════════════════════
   下载区 · 滚动驱动 + 光束
   S1 卡片差速视差 / S2 标题 scrub / S3 逐卡通电 / S4 进度光束条
   B1 顶部聚光射束 / B2 卡片扫描高光 / B3 边缘光束与四角光点
   B4 背景竖向光柱 / B5 按钮光束 / B6 3D 倾斜反光
   ──────────────────────────────────────────────────────────────────────────
   全部由 --p（0~1，reveal.js 单条 rAF 写入）与 .is-lit 驱动。
   JS 未执行时 --p 缺省为 0、无 .has-scrub，效果静止且元素照常可见。
   ══════════════════════════════════════════════════════════════════════════ */

/* 内容统一压在光束层之上 */
#download .section-header,
#download .beam-track,
#download .download-grid {
    position: relative;
    z-index: 1;
}

/* ── B4 背景竖向光柱：2 道柔光，随滚动缓慢横移并提亮 ── */
.download-beams {
    position: absolute;
    inset: 0;
    z-index: 0;
    overflow: hidden;
    pointer-events: none;
}

.beam-pillar {
    position: absolute;
    top: -10%;
    height: 120%;
    width: 300px;
    background: radial-gradient(58% 46% at 50% 50%,
                var(--brand-glow-soft) 0%, transparent 72%);
    opacity: 0;
    will-change: transform, opacity;
}

.beam-pillar--1 { left: 4%; }
.beam-pillar--2 { right: 8%; width: 240px; }

#download.has-scrub .beam-pillar {
    opacity: calc(.3 + var(--p, 0) * .7);
    animation: beam-pillar-drift 22s var(--ease) infinite alternate;
}

#download.has-scrub .beam-pillar--2 {
    animation-duration: 28s;
    animation-direction: alternate-reverse;
}

@keyframes beam-pillar-drift {
    from { transform: translate3d(-26px, 0, 0); }
    to   { transform: translate3d(26px, 0, 0); }
}

/* ── B1 顶部聚光射束：锥形光落在中间（Android）卡上，随滚动伸长、提亮 ── */
.beam-spot {
    position: absolute;
    left: 50%;
    top: -6%;
    width: min(660px, 78vw);
    height: 76%;
    transform-origin: top center;
    background: linear-gradient(to bottom,
                var(--brand-glow-strong) 0%,
                var(--brand-glow) 22%,
                var(--brand-glow-mid) 46%,
                var(--brand-glow-soft) 66%,
                transparent 86%);
    clip-path: polygon(37% 0, 63% 0, 100% 100%, 0 100%);
    opacity: 0;
    will-change: transform, opacity;
}

#download.has-scrub .beam-spot {
    opacity: calc(var(--p, 0) * .9);
    transform: translateX(-50%) scaleY(calc(.6 + var(--p, 0) * .4));
}

/* ── S4 滚动进度光束条：宽度 = 区块滚动进度，头部带亮点 ── */
.beam-track {
    max-width: var(--max-w);
    margin: 0 auto var(--space-8);
    height: 2px;
    border-radius: var(--radius-pill);
    background: var(--border);
    opacity: 0;
    transition: opacity .5s var(--ease);
}

#download.has-scrub .beam-track { opacity: 1; }

.beam-track i {
    display: block;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, var(--brand-glow-soft), var(--accent));
    box-shadow: 0 0 12px var(--brand-glow);
    transform: scaleX(var(--p, 0));
    transform-origin: left center;
}

.beam-track::after {
    content: "";
    position: absolute;
    top: 50%;
    left: calc(var(--p, 0) * 100%);
    width: 6px;
    height: 6px;
    margin: -3px 0 0 -3px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 10px 2px var(--brand-glow);
    opacity: 0;
}

#download.has-scrub .beam-track::after { opacity: calc(var(--p, 0) * 1.6); }

/* ── S2 标题 scrub：随进度上浮 + 字距收紧 ── */
#download.has-scrub .section-header h2 {
    transform: translateY(calc((1 - var(--p, 0)) * 14px));
    letter-spacing: calc(-1px - (1 - var(--p, 0)) * .6px);
    opacity: calc(.75 + var(--p, 0) * .25);
    will-change: transform, opacity;
}

/* ── S1 卡片差速视差 + B6 3D 倾斜反光（仅 ≥901px，移动端不做位移与倾斜）──
   注意用 901px 而不是 900px：文件后面 max-width:900px 的横滑断点要严格避开 */
@media (min-width: 901px) {
    #download.has-scrub .download-grid { perspective: 900px; }

    #download.has-scrub .download-grid > *:nth-child(1) {
        --parallax-y: calc((1 - var(--p, 0)) * 26px);
    }
    #download.has-scrub .download-grid > *:nth-child(2) {
        --parallax-y: calc((1 - var(--p, 0)) * 6px);
    }
    #download.has-scrub .download-grid > *:nth-child(3) {
        --parallax-y: calc((1 - var(--p, 0)) * -14px);
    }

    /* 视差每帧更新，transform 过渡不能沿用 .65s 的入场时长，否则拖影 */
    #download.has-scrub .download-card {
        transform: translateY(var(--parallax-y, 0px))
                   rotateX(var(--tilt-x, 0deg))
                   rotateY(var(--tilt-y, 0deg));
        transition: transform .28s linear,
                    border-color .25s var(--ease),
                    box-shadow .45s var(--ease),
                    opacity var(--reveal-duration) var(--ease-out);
        will-change: transform;
    }

    #download.has-scrub .download-card:hover {
        transform: translateY(calc(var(--parallax-y, 0px) - 4px))
                   rotateX(var(--tilt-x, 0deg))
                   rotateY(var(--tilt-y, 0deg));
    }

    #download.has-scrub .download-card:active {
        transform: translateY(var(--parallax-y, 0px)) scale(.98);
    }

    /* 待开放卡不上浮、不倾斜 */
    #download.has-scrub .download-card--disabled:hover,
    #download.has-scrub .download-card--disabled:active {
        transform: translateY(var(--parallax-y, 0px));
    }
}

/* ── B2 卡片扫描高光：点亮后斜向扫过一次 ── */
.card-scan {
    position: absolute;
    inset: 0;
    z-index: 2;
    border-radius: inherit;
    overflow: hidden;
    pointer-events: none;
}

.card-scan::before {
    content: "";
    position: absolute;
    top: -40%;
    left: -20%;
    width: 46%;
    height: 190%;
    background: linear-gradient(90deg, transparent,
                var(--brand-glow-mid) 45%, var(--brand-glow) 50%,
                var(--brand-glow-mid) 55%, transparent);
    transform: rotate(16deg) translateX(-180%);
    opacity: 0;
}

#download .download-card.is-lit .card-scan::before {
    animation: card-scan-sweep 1.15s var(--ease-out) .2s 1 both;
}

@keyframes card-scan-sweep {
    0%   { transform: rotate(16deg) translateX(-180%); opacity: 0; }
    18%  { opacity: 1; }
    100% { transform: rotate(16deg) translateX(420%); opacity: 0; }
}

/* ── B3 四角光点：配合边缘光束节奏闪动（仅推荐卡）── */
.card-scan::after {
    content: "";
    position: absolute;
    inset: 0;
    border-radius: inherit;
    background-image:
        radial-gradient(circle 5px at left top, var(--accent), transparent),
        radial-gradient(circle 5px at right top, var(--accent), transparent),
        radial-gradient(circle 5px at left bottom, var(--accent), transparent),
        radial-gradient(circle 5px at right bottom, var(--accent), transparent);
    opacity: 0;
}

#download .download-card.featured.is-lit .card-scan::after {
    animation: corners-blink 3.4s var(--ease) .8s infinite;
}

@keyframes corners-blink {
    0%, 62%, 100% { opacity: 0; }
    12%           { opacity: .85; }
    26%           { opacity: .2; }
    40%           { opacity: .6; }
}

/* ── B5 下载按钮光束：细光注入按钮，边框跟着亮三下后停 ── */
.btn-beam {
    position: absolute;
    top: 0;
    left: 50%;
    width: 22px;
    height: 46%;
    margin-left: -11px;
    border-radius: var(--radius-pill);
    background: linear-gradient(to bottom, transparent,
                var(--brand-glow-mid) 35%, var(--accent));
    pointer-events: none;
    opacity: 0;
    transform: translateY(-130%);
}

#download .download-card.featured.is-lit .btn-beam {
    animation: btn-beam-in 1s var(--ease-out) .85s 3 both;
}

/* 注意：这里必须带上 card-fade-in，否则会顶掉按钮的入场淡入导致按钮不可见 */
#download .download-card.featured.is-lit .btn-primary {
    animation: card-fade-in .5s var(--ease-out) .42s both,
               btn-edge-glow 1s var(--ease) .85s 3 both;
}

@keyframes btn-beam-in {
    0%   { transform: translateY(-130%); opacity: 0; }
    22%  { opacity: 1; }
    100% { transform: translateY(250%); opacity: 0; }
}

@keyframes btn-edge-glow {
    0%, 100% { box-shadow: 0 0 0 0 transparent; }
    45%      { box-shadow: 0 0 16px 2px var(--brand-glow); }
}

.download-more {
    max-width: var(--max-w);
    margin: var(--space-8) auto 0;
    text-align: center;
}

.download-more p {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: var(--space-3);
}

.download-more .alt-links {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    flex-wrap: wrap;
}

.download-more .alt-links a {
    color: var(--accent);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    padding: var(--space-2) var(--space-4);
    border: 1px solid var(--border);
    border-radius: var(--space-2);
    transition: background-color .2s var(--ease), border-color .2s var(--ease);
}

.download-more .alt-links a:hover {
    background: var(--surface);
    border-color: var(--accent);
}

/* ── Features ── */
.features-grid {
    max-width: var(--max-w);
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-5);
}

.feature-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--space-8) 28px;
    transition: border-color .25s var(--ease), transform .18s var(--ease);
    -webkit-tap-highlight-color: transparent;
}

.feature-card:active {
    transform: scale(.98);
}

/* 卡片错峰入场：逐张依次浮现，避免整块齐弹 */
.features-grid > .reveal:nth-child(1) { --reveal-delay: .04s; }
.features-grid > .reveal:nth-child(2) { --reveal-delay: .10s; }
.features-grid > .reveal:nth-child(3) { --reveal-delay: .16s; }
.features-grid > .reveal:nth-child(4) { --reveal-delay: .22s; }
.features-grid > .reveal:nth-child(5) { --reveal-delay: .28s; }
.features-grid > .reveal:nth-child(6) { --reveal-delay: .34s; }

.feature-card:hover {
    border-color: var(--border-hover);
}

.feature-card .feat-icon {
    width: 48px;
    height: 48px;
    background: var(--bg);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-5);
    color: var(--accent);
}

.feature-card .feat-icon svg {
    width: 24px;
    height: 24px;
}

.feature-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: var(--space-2);
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 15px;
}

/* ── Tutorial Section ── */
.tutorial-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.tutorial-item {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--space-6) 28px;
    display: flex;
    align-items: center;
    gap: var(--space-6);
    transition: border-color .25s var(--ease), transform .25s var(--ease);
    text-decoration: none;
    color: var(--text);
}

.tutorial-item:hover {
    border-color: var(--border-hover);
    transform: translateX(4px);
}

.tutorial-num {
    width: 44px;
    height: 44px;
    background: var(--bg);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 800;
    color: var(--accent);
    flex-shrink: 0;
}

.tutorial-info {
    flex: 1;
    min-width: 0;
}

.tutorial-info h3 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: var(--space-1);
}

.tutorial-info p {
    font-size: 14px;
    color: var(--text-secondary);
}

.tutorial-arrow {
    color: var(--text-secondary);
    flex-shrink: 0;
}

.tutorial-more {
    text-align: center;
    margin-top: var(--space-8);
}

/* ── Showcase ── */
.showcase-grid {
    max-width: var(--max-w);
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-5);
}

.showcase-item {
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border);
}

.showcase-item img {
    width: 100%;
    height: auto;
    display: block;
}

.showcase-item .caption {
    padding: var(--space-4) var(--space-5);
    background: var(--surface);
    font-size: 14px;
    color: var(--text-secondary);
}

.showcase-item .caption strong {
    color: var(--text);
}

/* ── CTA ── */
.cta-section {
    max-width: var(--max-w);
    margin: 0 auto;
    text-align: center;
}

.cta-box {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--space-16) 48px;
}

.cta-box h2 {
    font-size: 36px;
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: var(--space-3);
}

.cta-box p {
    color: var(--text-secondary);
    font-size: 17px;
    margin-bottom: var(--space-8);
}

.cta-box .cta-actions {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    flex-wrap: wrap;
}

/* ── Footer ── */
footer {
    border-top: 1px solid var(--border);
    padding: var(--space-10) var(--space-6);
    text-align: center;
    color: var(--text-secondary);
    font-size: 14px;
}

footer .footer-links {
    display: flex;
    gap: var(--space-6);
    justify-content: center;
    margin-bottom: var(--space-4);
    flex-wrap: wrap;
}

footer .footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
}

footer .footer-links a:hover {
    color: var(--text);
}

/* 备案号：与版权段落之间留出间距，链接继承次级文字色 */
footer .footer-beian {
    margin-top: var(--space-2);
    font-size: 12px;
}
footer .footer-beian a {
    color: inherit;
    text-decoration: none;
    transition: color .2s var(--ease);
}
footer .footer-beian a:hover {
    color: var(--text);
}

/* ── 内容弹窗（关于我们 / 用户协议 / 隐私政策）── */
.content-modal {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: none;
}

.content-modal.is-open {
    display: block;
}

.content-modal__backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, .72);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

.content-modal__dialog {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: min(720px, calc(100vw - 32px));
    max-height: min(86vh, 760px);
    display: flex;
    flex-direction: column;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: 0 24px 60px rgba(0, 0, 0, .55);
    overflow: hidden;
}

.content-modal__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
    padding: var(--space-5) var(--space-6);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}

.content-modal__title {
    margin: 0;
    font-size: 20px;
    font-weight: 700;
    color: var(--text);
}

.content-modal__close {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: none;
    background: var(--bg);
    color: var(--text-secondary);
    border-radius: var(--radius);
    font-size: 22px;
    line-height: 1;
    cursor: pointer;
    transition: background-color .2s var(--ease), color .2s var(--ease);
    flex-shrink: 0;
}

.content-modal__close:hover {
    background: var(--surface-hover);
    color: var(--text);
}

.content-modal__body {
    flex: 1 1 auto;
    min-height: 0;
    padding: var(--space-6);
    overflow-y: auto;
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.8;
    -webkit-overflow-scrolling: touch;
}

.content-modal__body h3 {
    color: var(--text);
    font-size: 16px;
    font-weight: 700;
    margin: var(--space-6) 0 var(--space-3);
}

.content-modal__body h3:first-child {
    margin-top: 0;
}

.content-modal__body p {
    margin: 0 0 var(--space-4);
}

.content-modal__body ul {
    margin: 0 0 var(--space-4);
    padding-left: var(--space-6);
}

.content-modal__body li {
    margin-bottom: var(--space-2);
}

.content-modal__body strong {
    color: var(--text);
    font-weight: 600;
}

.content-modal__body a {
    color: var(--accent);
    text-decoration: none;
}

.content-modal__body a:hover {
    text-decoration: underline;
}

.content-modal__updated {
    margin-top: var(--space-6);
    padding-top: var(--space-4);
    border-top: 1px solid var(--border);
    font-size: 13px;
    color: var(--text-secondary);
    opacity: .7;
}

@media (prefers-reduced-motion: no-preference) {
    .content-modal__dialog {
        animation: cm-pop .22s var(--ease);
    }
    @keyframes cm-pop {
        from { opacity: 0; transform: translate(-50%, -46%) scale(.98); }
        to   { opacity: 1; transform: translate(-50%, -50%) scale(1); }
    }
}

@media (max-width: 640px) {
    .content-modal__dialog {
        width: calc(100vw - 24px);
        max-height: 88vh;
    }
    .content-modal__header {
        padding: var(--space-4) var(--space-5);
    }
    .content-modal__body {
        padding: var(--space-5);
    }
}

/* ── Responsive: Tablet (≤900px) ── */
@media (max-width: 900px) {
    .hero {
        flex-direction: column;
        gap: 48px;
        padding: 48px var(--space-5) 60px;
    }

    .hero h1 {
        font-size: 36px;
        letter-spacing: -1px;
    }

    .hero p {
        font-size: 16px;
    }

    .download-grid {
        grid-template-columns: 1fr;
        max-width: 420px;
    }

    /* 移动端 GPU 兜底：关掉两个最贵的无限动画。
       流光边框走 conic-gradient + mask-composite，四角光点逐帧改 opacity，
       在移动端每帧都要重绘。渐变与描边样式保留，只是不再逐帧动。 */
    .download-card::after {
        animation: none;
    }

    #download .download-card.featured.is-lit .card-scan::after {
        animation: none;
    }

    .features-grid {
        grid-template-columns: 1fr 1fr;
    }

    .showcase-grid {
        display: flex;
        gap: var(--space-4);
        overflow-x: auto;
        scroll-snap-type: x mandatory;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
    }

    .showcase-grid::-webkit-scrollbar {
        display: none;
    }

    .showcase-item {
        flex: 0 0 82%;
        scroll-snap-align: center;
    }

    section {
        padding: var(--space-16) var(--space-5);
    }

    .section-header {
        margin-bottom: var(--space-10);
    }

    .section-header h2 {
        font-size: 28px;
    }

    .section-header p {
        font-size: 15px;
    }

    .nav-links {
        display: none;
    }

    .hamburger {
        display: flex;
    }

    /* 向下滚收起导航、向上滚立即显现（原生 App 观感） */
    header.is-hidden {
        transform: translateY(-100%);
    }

    .cta-box {
        padding: 48px var(--space-8);
    }

    .cta-box h2 {
        font-size: 28px;
    }
}

/* ── Responsive: Phone (≤640px) ── */
@media (max-width: 640px) {
    :root {
        --reveal-distance: 16px;
        --reveal-duration: .45s;
    }

    html.js .reveal {
        transition-duration: .45s;
    }

    /* 手机上 hero 各元素近乎同时进场，去掉桌面端的拖沓 stagger */
    .hero-text > .reveal:nth-child(1) { --reveal-delay: 0s; }
    .hero-text > .reveal:nth-child(2) { --reveal-delay: .05s; }
    .hero-text > .reveal:nth-child(3) { --reveal-delay: .1s; }
    .hero-text > .reveal:nth-child(4) { --reveal-delay: .15s; }
    .hero-img.reveal { --reveal-delay: .08s; }

    nav {
        padding: 0 var(--space-4);
        height: 56px;
    }

    .logo-area {
        font-size: 17px;
        gap: var(--space-2);
    }

    .logo-area img {
        height: 28px;
    }

    .mobile-nav-overlay {
        top: 56px;
    }

    /* 刘海屏 / 圆角屏安全区适配 */
    nav,
    .mobile-nav-overlay {
        padding-left: max(var(--space-4), env(safe-area-inset-left));
        padding-right: max(var(--space-4), env(safe-area-inset-right));
    }

    footer {
        padding-left: max(var(--space-4), env(safe-area-inset-left));
        padding-right: max(var(--space-4), env(safe-area-inset-right));
        padding-bottom: max(var(--space-6), env(safe-area-inset-bottom));
    }

    .footer-links a {
        display: inline-flex;
        align-items: center;
        min-height: 44px;
    }

    .hero {
        padding: var(--space-10) var(--space-4) 48px;
        gap: 36px;
        text-align: center;
    }

    .hero h1 {
        font-size: 30px;
        letter-spacing: -.8px;
    }

    .hero h1 br {
        display: none;
    }

    .hero p {
        font-size: 15px;
        max-width: 100%;
    }

    .hero-badge {
        font-size: 12px;
        padding: 5px var(--space-3);
        margin-bottom: var(--space-4);
    }

    .hero-actions {
        flex-direction: column;
    }

    .hero-actions .btn {
        width: 100%;
        justify-content: center;
    }

    .hero-img {
        order: -1;
    }

    .hero-img img {
        max-width: 25%;
        border-radius: var(--radius-md);
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: var(--space-3);
    }

    .feature-card {
        padding: var(--space-6) var(--space-5);
    }

    .feature-card h3 {
        font-size: 16px;
    }

    .feature-card p {
        font-size: 14px;
    }

    .download-grid {
        max-width: 100%;
        gap: var(--space-3);
    }

    .download-card {
        padding: 28px var(--space-5);
    }

    .download-card h3 {
        font-size: 18px;
    }

    .download-more .alt-links {
        gap: var(--space-2);
    }

    .download-more .alt-links a {
        font-size: 13px;
        padding: var(--space-2) 14px;
    }

    .showcase-grid {
        gap: var(--space-3);
    }

    .showcase-item .caption {
        padding: var(--space-3) var(--space-4);
        font-size: 13px;
    }

    .tutorial-list {
        gap: 10px;
    }

    .tutorial-item {
        padding: 18px var(--space-5);
        gap: var(--space-4);
    }

    .tutorial-num {
        width: 38px;
        height: 38px;
        font-size: 17px;
        border-radius: var(--radius-md);
    }

    .tutorial-info h3 {
        font-size: 15px;
    }

    .tutorial-info p {
        font-size: 13px;
    }

    .tutorial-arrow svg {
        width: 16px;
        height: 16px;
    }

    .tutorial-more {
        margin-top: var(--space-6);
    }

    .cta-box {
        padding: var(--space-10) var(--space-5);
    }

    .cta-box h2 {
        font-size: 24px;
    }

    .cta-box p {
        font-size: 15px;
        margin-bottom: var(--space-6);
    }

    .cta-actions {
        flex-direction: column;
    }

    .cta-actions .btn {
        width: 100%;
        justify-content: center;
    }

    section {
        padding: 48px var(--space-4);
    }

    .section-header {
        margin-bottom: var(--space-8);
    }

    .section-header h2 {
        font-size: 26px;
    }

    .section-header p {
        font-size: 14px;
    }

    footer {
        padding: var(--space-8) var(--space-4) var(--space-6);
    }

    footer .footer-links {
        gap: var(--space-4);
        font-size: 13px;
    }

    footer p {
        font-size: 12px;
    }
}

/* ── Responsive: Small Phone (≤380px) ── */
@media (max-width: 380px) {
    .hero h1 {
        font-size: 26px;
    }

    .hero p {
        font-size: 14px;
    }

    .btn {
        padding: var(--space-3) var(--space-5);
        font-size: 14px;
    }

    .btn-large {
        padding: 14px var(--space-6);
        font-size: 15px;
    }

    .btn svg {
        width: 18px;
        height: 18px;
    }

    .section-header h2 {
        font-size: 23px;
    }

    .cta-box h2 {
        font-size: 21px;
    }

    .download-more .alt-links a {
        font-size: 12px;
        padding: 6px var(--space-3);
    }

    .mobile-nav-overlay a {
        font-size: 16px;
        padding: 14px var(--space-4);
    }
}