:root {
  --bg: #f5f7fb;
  --bg-soft: #eef2f9;
  --panel: #ffffff;
  --ink: #152033;
  --ink-soft: #4a5870;
  --mute: #7a8699;
  --line: rgba(21, 32, 51, 0.1);
  --line-hi: rgba(21, 32, 51, 0.18);
  --blue: #2f6bff;
  --blue-deep: #1d4ed8;
  --blue-mist: #c9d8ff;
  --max: 1120px;
  --pad: clamp(20px, 5vw, 48px);
  --display: 'Syne', system-ui, sans-serif;
  --serif: 'Instrument Serif', Georgia, serif;
  --stage-radius: 14px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

#top,
#workflow,
#download,
#demo,
#community {
  scroll-margin-top: 0;
}

#workflow,
#download,
#demo,
#community {
  scroll-margin-top: 72px;
}

body {
  margin: 0;
  overflow-x: clip;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--display);
  font-weight: 500;
  line-height: 1.45;
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.skip {
  position: absolute;
  left: -999px;
  top: 0;
  z-index: 99;
  padding: 10px 14px;
  background: var(--ink);
  color: #fff;
}

.skip:focus {
  left: 12px;
  top: 12px;
}

.scroll-progress {
  position: fixed;
  inset: 0 0 auto;
  z-index: 40;
  height: 2px;
  background: transparent;
  pointer-events: none;
}

.scroll-progress i {
  display: block;
  height: 100%;
  width: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--blue), #5b8cff);
  transition: transform 0.08s linear;
}

.top {
  position: fixed;
  inset: 0 0 auto;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 20px var(--pad);
  overflow: visible;
  background: linear-gradient(180deg, rgba(245, 247, 251, 0.94), rgba(245, 247, 251, 0));
  backdrop-filter: blur(10px);
  transition:
    background 0.35s ease,
    padding 0.35s var(--ease),
    box-shadow 0.35s ease;
}

.top.is-scrolled {
  padding-top: 14px;
  padding-bottom: 14px;
  background: rgba(245, 247, 251, 0.88);
  box-shadow: 0 1px 0 var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.brand img {
  width: 30px;
  height: 30px;
  border-radius: 8px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 26px;
  margin-left: auto;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-soft);
}

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

.nav-src {
  padding: 8px 14px;
  border: 1px solid var(--line-hi);
  color: var(--ink) !important;
  background: rgba(255, 255, 255, 0.65);
  transition:
    background 0.25s ease,
    border-color 0.25s ease,
    transform 0.25s ease;
}

.nav-src:hover {
  border-color: var(--blue);
  background: #fff;
  transform: translateY(-1px);
}

/* 语言切换入口（.nav 之外常驻，窄屏隐藏 .nav 时仍可见） */
.nav-lang {
  display: inline-flex;
  align-items: center;
  flex: 0 0 auto;
  padding: 8px 14px;
  border: 1px solid var(--line-hi);
  border-radius: 999px;
  color: var(--ink-soft) !important;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.02em;
  white-space: nowrap;
  background: rgba(255, 255, 255, 0.65);
  transition:
    border-color 0.25s ease,
    color 0.25s ease,
    background 0.25s ease;
}

.nav-lang:hover {
  border-color: var(--blue);
  color: var(--blue-deep) !important;
  background: #fff;
}

.mobile-nav .nav-lang {
  justify-content: center;
  margin-top: 8px;
}

.mobile-menu {
  display: none;
}

/* —— Hero —— */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  gap: clamp(28px, 4vh, 40px);
  padding: clamp(108px, 14vh, 136px) var(--pad) clamp(36px, 5vh, 56px);
  overflow: visible;
  isolation: isolate;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  background: var(--bg);
  will-change: transform;
}

.hero-wash {
  position: absolute;
  inset: -8%;
  background:
    radial-gradient(90% 70% at 78% 18%, rgba(47, 107, 255, 0.18), transparent 58%),
    radial-gradient(70% 55% at 12% 80%, rgba(201, 216, 255, 0.45), transparent 60%),
    linear-gradient(165deg, #eef3ff 0%, var(--bg) 42%, #e8edf6 100%);
  will-change: transform;
  animation: wash 18s ease-in-out infinite alternate;
}

.hero-mesh {
  position: absolute;
  inset: 0;
  opacity: 0.28;
  background-image:
    linear-gradient(rgba(47, 107, 255, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(47, 107, 255, 0.07) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.4), transparent 75%);
  will-change: transform;
  animation: grid 26s linear infinite;
}

.hero-body {
  width: min(var(--max), 100%);
  margin: 0 auto;
  flex-shrink: 0;
}

.eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--blue-deep);
}

.hero h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.6rem, 6.5vw, 4.6rem);
  font-weight: 400;
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: var(--ink);
  text-wrap: balance;
}

.hero h1 em {
  font-style: italic;
  color: var(--blue-deep);
}

.lede {
  margin: 16px 0 0;
  font-size: clamp(1rem, 1.5vw, 1.12rem);
  color: var(--ink-soft);
  line-height: 1.55;
  text-wrap: pretty;
}

.hero-foot {
  width: min(var(--max), 100%);
  margin: 0 auto;
  flex-shrink: 0;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 24px;
  font-size: 14px;
  font-weight: 700;
  border: 1px solid transparent;
  transition:
    transform 0.28s var(--ease),
    background 0.25s ease,
    border-color 0.25s ease,
    box-shadow 0.25s ease;
}

.btn-solid {
  background: var(--blue);
  color: #fff;
}

.btn-solid:hover {
  background: var(--blue-deep);
  transform: translateY(-2px);
  box-shadow: 0 12px 24px rgba(47, 107, 255, 0.2);
}

.btn-line {
  border-color: var(--line-hi);
  background: rgba(255, 255, 255, 0.75);
  color: var(--ink);
}

.btn-line:hover {
  border-color: var(--blue);
  background: #fff;
  transform: translateY(-2px);
}

.hero-meta {
  margin: 16px 0 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--mute);
}

.hero-meta i {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: rgba(47, 107, 255, 0.45);
}

/* —— Cover Flow —— */
.coverflow {
  --cf-w: min(58vw, 640px);
  position: relative;
  width: min(1180px, 100%);
  margin: 0 auto;
  flex: 1 1 auto;
  min-height: 0;
  padding: 8px 0 28px;
}

.cf-stage {
  position: relative;
  height: clamp(280px, 42vw, 420px);
  perspective: 1600px;
  perspective-origin: 50% 45%;
  overflow: visible;
}

.cf-track {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
}

.cf-card {
  position: absolute;
  top: 50%;
  left: 50%;
  width: var(--cf-w);
  aspect-ratio: 16 / 10;
  margin: 0;
  border-radius: 18px;
  overflow: hidden;
  background: #10151d;
  border: 1px solid rgba(255, 255, 255, 0.08);
  transform-origin: center center;
  transform-style: preserve-3d;
  cursor: pointer;
  box-shadow: 0 22px 50px rgba(15, 23, 42, 0.28);
  transition:
    transform 0.55s var(--ease),
    opacity 0.45s var(--ease),
    filter 0.45s ease,
    box-shadow 0.45s ease;
  opacity: 0;
  pointer-events: none;
}

.cf-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
}

.cf-card figcaption {
  position: absolute;
  inset: auto 0 0;
  padding: 48px 22px 20px;
  background: linear-gradient(180deg, transparent, rgba(8, 12, 18, 0.88) 55%);
  color: #fff;
  pointer-events: none;
}

.cf-card strong {
  display: block;
  font-size: clamp(1.15rem, 2.2vw, 1.55rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.cf-card span {
  display: block;
  margin-top: 6px;
  font-size: 0.88rem;
  color: rgba(255, 255, 255, 0.72);
  font-weight: 500;
}

.cf-card[data-offset='0'] {
  opacity: 1;
  pointer-events: auto;
  cursor: default;
  transform: translate3d(-50%, -50%, 0) rotateY(0deg) scale(1);
  box-shadow: 0 28px 64px rgba(15, 23, 42, 0.36);
  filter: none;
}

.cf-card[data-offset='-1'] {
  opacity: 0.88;
  pointer-events: auto;
  transform: translate3d(calc(-50% - 42%), -50%, -120px) rotateY(48deg) scale(0.86);
  filter: brightness(0.72);
}

.cf-card[data-offset='1'] {
  opacity: 0.88;
  pointer-events: auto;
  transform: translate3d(calc(-50% + 42%), -50%, -120px) rotateY(-48deg) scale(0.86);
  filter: brightness(0.72);
}

.cf-card[data-offset='-2'] {
  opacity: 0.35;
  transform: translate3d(calc(-50% - 68%), -50%, -260px) rotateY(58deg) scale(0.72);
  filter: brightness(0.5);
}

.cf-card[data-offset='2'] {
  opacity: 0.35;
  transform: translate3d(calc(-50% + 68%), -50%, -260px) rotateY(-58deg) scale(0.72);
  filter: brightness(0.5);
}

.cf-card[data-offset='-3'],
.cf-card[data-offset='3'],
.cf-card[data-offset='-4'],
.cf-card[data-offset='4'] {
  opacity: 0;
  transform: translate3d(-50%, -50%, -400px) scale(0.6);
  filter: brightness(0.4);
}

.cf-nav {
  position: absolute;
  top: 50%;
  translate: 0 -50%;
  z-index: 30;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 1px solid rgba(21, 32, 51, 0.12);
  background: rgba(255, 255, 255, 0.82);
  color: var(--ink);
  font-size: 28px;
  line-height: 1;
  display: grid;
  place-items: center;
  backdrop-filter: blur(8px);
  transition:
    background 0.2s ease,
    transform 0.2s ease,
    border-color 0.2s ease;
}

.cf-nav:hover {
  background: #fff;
  border-color: var(--blue);
  transform: scale(1.05);
}

.cf-prev {
  left: max(0px, calc(50% - var(--cf-w) * 0.92));
}

.cf-next {
  right: max(0px, calc(50% - var(--cf-w) * 0.92));
}

.cf-dots {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  margin-top: 18px;
}

.cf-dot {
  width: 8px;
  height: 8px;
  border-radius: 3px;
  background: rgba(21, 32, 51, 0.18);
  transition:
    width 0.3s var(--ease),
    background 0.25s ease,
    border-radius 0.3s ease;
}

.cf-dot.is-active {
  width: 28px;
  border-radius: 999px;
  background: var(--blue);
}

/* —— Statement —— */
.statement {
  background: var(--panel);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.statement-inner {
  width: min(var(--max), 100%);
  margin: 0 auto;
  padding: clamp(64px, 10vw, 96px) var(--pad);
}

.statement h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2rem, 4.2vw, 3.1rem);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: -0.025em;
  text-wrap: balance;
}

.statement p {
  margin: 18px 0 0;
  color: var(--ink-soft);
  font-size: 1.05rem;
  line-height: 1.65;
  text-wrap: pretty;
}

.section-label {
  margin: 0 0 18px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--blue);
}

/* —— Demo —— */
.demo {
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 80% at 50% 0%, rgba(47, 107, 255, 0.08), transparent 55%),
    var(--bg);
}

.demo-inner {
  width: min(var(--max), 100%);
  margin: 0 auto;
  padding: clamp(72px, 11vw, 112px) var(--pad);
}

.demo h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.15rem, 4.4vw, 3.2rem);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

.demo-lede {
  margin: 14px 0 0;
  max-width: 36rem;
  color: var(--ink-soft);
  font-size: 1.05rem;
  line-height: 1.6;
}

.demo-stage {
  margin-top: clamp(28px, 4vw, 40px);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(16px, 2.5vw, 28px);
  align-items: stretch;
}

.demo-graph,
.demo-video {
  margin: 0;
  min-width: 0;
}

.demo-graph img,
.demo-video video {
  display: block;
  width: 100%;
  height: auto;
  /* 与 demo 视频分辨率一致（864×496） */
  aspect-ratio: 864 / 496;
  object-fit: contain;
  border-radius: var(--stage-radius);
  border: 1px solid var(--line-hi);
  background: #0b1220;
  box-shadow: 0 24px 60px rgba(21, 32, 51, 0.12);
}

.demo-graph figcaption,
.demo-video figcaption {
  margin-top: 10px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--mute);
}

/* —— Workflow —— */
.workflow {
  width: min(var(--max), 100%);
  margin: 0 auto;
  padding: clamp(72px, 11vw, 112px) var(--pad);
}

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
}

.steps li {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 18px;
  padding: 26px 0;
  border-top: 1px solid var(--line);
  align-items: start;
  transition-delay: var(--stagger, 0ms);
}

.steps li:last-child {
  border-bottom: 1px solid var(--line);
}

/* 文本列可收缩，避免长词 / 长链接把行撑出容器 */
.steps li > div {
  min-width: 0;
}

.steps .n {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--blue);
  padding-top: 5px;
}

.steps h3 {
  margin: 0;
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.steps p {
  margin: 8px 0 0;
  color: var(--ink-soft);
  font-size: 0.98rem;
  line-height: 1.6;
  text-wrap: pretty;
}

/* —— Download —— */
.download {
  background: var(--bg-soft);
  border-top: 1px solid var(--line);
  padding: clamp(72px, 11vw, 112px) var(--pad);
}

.download-head {
  width: min(var(--max), 100%);
  margin: 0 auto 8px;
}

.download h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.15rem, 4.4vw, 3.2rem);
  font-weight: 400;
  letter-spacing: -0.02em;
}

.dl-list {
  list-style: none;
  width: min(var(--max), 100%);
  margin: 32px auto 0;
  padding: 0;
  background: var(--panel);
  border: 1px solid var(--line);
}

.dl-list a {
  display: grid;
  grid-template-columns: 1.2fr 1.4fr auto;
  gap: 16px;
  align-items: center;
  padding: 24px 22px;
  border-bottom: 1px solid var(--line);
  transition:
    background 0.25s ease,
    padding-left 0.25s ease;
}

.dl-list li:last-child a {
  border-bottom: none;
}

.dl-list a:hover {
  background: #f7f9ff;
  padding-left: 28px;
}

.dl-os {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.dl-file {
  color: var(--mute);
  font-size: 0.92rem;
}

.dl-go {
  color: var(--blue);
  font-size: 1.2rem;
  transition: transform 0.25s ease;
}

.dl-list a:hover .dl-go {
  transform: translateX(5px);
}

.dl-note {
  width: min(var(--max), 100%);
  margin: 18px auto 0;
  font-size: 0.88rem;
  color: var(--mute);
}

.dl-note code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color: var(--blue-deep);
  font-size: 0.9em;
}

/* —— Community —— */
.community {
  background: var(--bg);
  border-top: 1px solid var(--line);
  padding: clamp(72px, 11vw, 112px) var(--pad);
}

.community-head {
  width: min(var(--max), 100%);
  margin: 0 auto;
}

.community h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.15rem, 4.4vw, 3.2rem);
  font-weight: 400;
  letter-spacing: -0.02em;
}

.community-lede {
  margin: 12px 0 0;
  max-width: 36rem;
  color: var(--ink-soft);
  font-size: 1.02rem;
  line-height: 1.55;
}

.community-body {
  width: min(var(--max), 100%);
  margin: 40px auto 0;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: clamp(28px, 5vw, 56px);
  align-items: center;
}

.community-qr {
  margin: 0;
  width: min(220px, 56vw);
}

.community-qr img {
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  background: #fff;
}

.community-qr figcaption {
  margin-top: 12px;
  color: var(--mute);
  font-size: 0.88rem;
  text-align: center;
}

.community-meta {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.community-meta li {
  display: grid;
  gap: 4px;
}

.community-meta span {
  color: var(--mute);
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.community-meta strong,
.community-meta a {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.community-meta a:hover {
  color: var(--blue-deep);
}

.foot {
  background: var(--panel);
  border-top: 1px solid var(--line);
  padding: 28px var(--pad) 40px;
}

.foot-row {
  width: min(var(--max), 100%);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  font-size: 13px;
  color: var(--mute);
}

.foot-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 700;
}

.foot-brand img {
  width: 22px;
  height: 22px;
  border-radius: 5px;
}

.foot-links {
  display: flex;
  gap: 18px;
}

.foot-links a:hover {
  color: var(--blue-deep);
}

.reveal,
.reveal-item {
  opacity: 0;
  filter: blur(5px);
  transform: translate3d(0, 20px, 0) scale(0.99);
  transition:
    opacity 0.38s var(--ease),
    transform 0.42s var(--ease),
    filter 0.38s var(--ease);
  transition-delay: var(--d, var(--stagger, 0s));
  will-change: transform, opacity, filter;
}

.reveal-rise {
  transform: translate3d(0, 28px, 0) scale(0.98);
}

.reveal-blur {
  filter: blur(8px);
  transform: translate3d(0, 16px, 0) scale(1.01);
}

.reveal-stage {
  filter: blur(7px);
  transform: translate3d(0, 36px, 0) rotateX(6deg) scale(0.96);
  transform-origin: 50% 80%;
}

.reveal.in,
.reveal-item.in {
  opacity: 1;
  filter: blur(0);
  transform: none;
}

.reveal-stage.in {
  transform: none;
}

@keyframes wash {
  from {
    transform: scale(1);
  }
  to {
    transform: scale(1.04) translate(-1%, 0.5%);
  }
}

@keyframes grid {
  from {
    background-position: 0 0, 0 0;
  }
  to {
    background-position: 48px 48px, 48px 48px;
  }
}

@media (max-width: 1200px) {
  .top {
    padding: 14px var(--pad);
    background: rgba(245, 247, 251, 0.96);
    box-shadow: 0 1px 0 var(--line);
  }

  .top .nav {
    display: none;
  }

  /* 导航折叠后，语言入口补位推到右侧，紧邻汉堡菜单 */
  .nav-lang {
    margin-left: auto;
  }

  .mobile-menu {
    position: static;
    display: block;
    flex: 0 0 auto;
  }

  .mobile-menu summary {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 0 14px;
    border: 1px solid var(--line-hi);
    background: rgba(255, 255, 255, 0.92);
    color: var(--ink);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    list-style: none;
  }

  .mobile-menu summary::-webkit-details-marker {
    display: none;
  }

  .mobile-menu[open] summary {
    border-color: var(--blue);
    color: var(--blue-deep);
  }

  .mobile-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 35;
    width: auto;
    max-height: min(70vh, calc(100svh - 80px));
    overflow-y: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    display: grid;
    gap: 2px;
    padding: 10px var(--pad) 14px;
    margin: 0;
    background: rgba(255, 255, 255, 0.98);
    border-bottom: 1px solid var(--line-hi);
    box-shadow: 0 18px 40px rgba(21, 32, 51, 0.16);
    backdrop-filter: blur(14px);
  }

  .mobile-nav a {
    min-height: 48px;
    display: flex;
    align-items: center;
    padding: 0 14px;
    color: var(--ink-soft);
    font-size: 15px;
    font-weight: 700;
    border-radius: 8px;
  }

  .mobile-nav a:hover,
  .mobile-nav a:focus-visible {
    color: var(--blue-deep);
    background: var(--bg-soft);
  }

  .demo-stage {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
    padding-top: 100px;
    overflow: clip;
  }

  .coverflow {
    --cf-w: min(86vw, 420px);
    overflow: hidden;
  }

  .cf-stage {
    height: clamp(240px, 58vw, 320px);
    overflow: hidden;
  }

  .cf-card:not(.is-active) {
    opacity: 0;
    pointer-events: none;
  }

  .cf-dots {
    gap: 0;
    margin-top: 6px;
  }

  .cf-dot,
  .cf-dot.is-active {
    width: 36px;
    height: 36px;
    display: grid;
    place-items: center;
    border-radius: 0;
    background: transparent;
  }

  .cf-dot::after {
    content: '';
    width: 8px;
    height: 8px;
    border-radius: 3px;
    background: rgba(21, 32, 51, 0.18);
    transition:
      width 0.3s var(--ease),
      background 0.25s ease;
  }

  .cf-dot.is-active::after {
    width: 26px;
    border-radius: 999px;
    background: var(--blue);
  }

  .cf-prev {
    left: 8px;
  }

  .cf-next {
    right: 8px;
  }

  .dl-list a {
    grid-template-columns: 1fr auto;
  }

  .dl-file {
    grid-column: 1;
  }

  .dl-go {
    grid-row: 1 / span 2;
  }

  .community-body {
    grid-template-columns: 1fr;
    justify-items: start;
  }

  .foot-row {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 520px) {
  :root {
    --pad: 16px;
  }

  .brand span {
    font-size: 14px;
  }

  .hero {
    gap: 22px;
    padding-top: 92px;
  }

  .hero h1 {
    font-size: clamp(2.25rem, 12vw, 3.1rem);
  }

  .lede {
    font-size: 0.98rem;
  }

  .cta {
    display: grid;
    grid-template-columns: 1fr;
  }

  .btn {
    width: 100%;
  }

  .cf-stage {
    height: clamp(220px, 66vw, 290px);
  }

  .cf-card figcaption {
    padding: 16px;
  }

  .cf-card figcaption span {
    display: none;
  }

  .foot-links {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }

  .reveal,
  .reveal-item,
  .reveal-stage {
    opacity: 1;
    filter: none;
    transform: none;
  }

  .cf-card {
    transition: none !important;
  }
}

/* ===== 深色模式：跟随系统（JS 同步类）或手动选择 ===== */
html.dark {
  --bg: #0e1420;
  --bg-soft: #1b2436;
  --panel: #131b2a;
  --ink: #e7ecf6;
  --ink-soft: #b7c2d8;
  --mute: #8291ab;
  --line: rgba(231, 236, 246, 0.12);
  --line-hi: rgba(231, 236, 246, 0.22);
  --blue: #6f9bff;
  --blue-deep: #93b1ff;
  --blue-mist: #1d2a45;
  color-scheme: dark;
}

html.light {
  color-scheme: light;
}

html.dark .top {
  background: linear-gradient(180deg, rgba(14, 20, 32, 0.94), rgba(14, 20, 32, 0));
}

html.dark .top.is-scrolled {
  background: rgba(14, 20, 32, 0.88);
}

html.dark .nav-src,
html.dark .nav-lang {
  background: rgba(19, 27, 42, 0.65);
}

html.dark .nav-src:hover {
  background: var(--panel);
}

html.dark .hero-wash {
  background:
    radial-gradient(90% 70% at 78% 18%, rgba(111, 155, 255, 0.16), transparent 58%),
    radial-gradient(70% 55% at 12% 80%, rgba(29, 42, 69, 0.55), transparent 60%),
    linear-gradient(165deg, #131b31 0%, var(--bg) 42%, #0d1320 100%);
}

html.dark .hero-mesh {
  background:
    linear-gradient(rgba(111, 155, 255, 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(111, 155, 255, 0.08) 1px, transparent 1px);
}

html.dark .btn-line {
  background: rgba(19, 27, 42, 0.75);
}

html.dark .cf-nav {
  border-color: var(--line-hi);
  background: rgba(19, 27, 42, 0.82);
}

html.dark .cf-dot,
html.dark .cf-dot::after {
  background: rgba(231, 236, 246, 0.22);
}

html.dark .dl-list a:hover {
  background: var(--bg-soft);
}

html.dark .mobile-menu summary {
  background: rgba(19, 27, 42, 0.92);
}

html.dark .mobile-nav {
  background: rgba(19, 27, 42, 0.98);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.5);
}

/* 主题切换按钮（与 .nav-lang 同族） */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  padding: 0;
  border: 1px solid var(--line-hi);
  border-radius: 999px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1;
  background: rgba(255, 255, 255, 0.65);
  cursor: pointer;
  transition:
    border-color 0.25s ease,
    color 0.25s ease,
    background 0.25s ease;
}

.theme-toggle:hover {
  border-color: var(--blue);
  color: var(--ink);
}

html.dark .theme-toggle {
  background: rgba(19, 27, 42, 0.65);
}

/* ===== 特色功能：AI 对话 + MCP ===== */
#features {
  scroll-margin-top: 72px;
}

.hl-features {
  width: min(var(--max), 100%);
  margin: 0 auto;
  padding: clamp(64px, 10vw, 96px) var(--pad);
  border-bottom: 1px solid var(--line);
}

.hl-features h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2rem, 4.2vw, 3.1rem);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: -0.025em;
}

.hl-lede {
  margin: 14px 0 0;
  max-width: 720px;
  color: var(--ink-soft);
  font-size: 1.05rem;
  line-height: 1.65;
  text-wrap: pretty;
}

.hl-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: clamp(16px, 2.5vw, 24px);
  margin-top: clamp(28px, 4vw, 40px);
}

.hl-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: clamp(22px, 3vw, 30px) clamp(20px, 2.6vw, 28px);
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel);
  box-shadow: 0 18px 44px rgba(9, 14, 24, 0.08);
}

.hl-card::before {
  content: '';
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  border-radius: 16px 16px 0 0;
  background: linear-gradient(90deg, var(--blue), #8a5bff);
}

.hl-badge {
  align-self: flex-start;
  padding: 3px 10px;
  border-radius: 999px;
  background: rgba(47, 107, 255, 0.12);
  color: var(--blue-deep);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.hl-card h3 {
  margin: 0;
  font-family: var(--serif);
  font-size: 1.55rem;
  font-weight: 400;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.hl-card p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.98rem;
  line-height: 1.68;
  text-wrap: pretty;
}

.hl-card code {
  padding: 1px 6px;
  border-radius: 6px;
  background: rgba(47, 107, 255, 0.1);
  color: var(--blue-deep);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, 'Courier New', monospace;
  font-size: 0.92em;
}

.hl-link {
  margin-top: auto;
  align-self: flex-start;
  color: var(--blue-deep);
  font-size: 0.92rem;
  font-weight: 700;
}

.hl-link:hover {
  text-decoration: underline;
}

html.dark .hl-card {
  box-shadow: 0 18px 44px rgba(0, 0, 0, 0.35);
}

@media (max-width: 860px) {
  .hl-grid {
    grid-template-columns: 1fr;
  }
}