/*
 * 流界官网样式。沿用应用的「精密仪表」规范（docs/design.md）：
 * 瑞士式极简 + 扁平；中性石板灰承载结构，品牌蓝只给接缝、键鼠的去向和主要操作；
 * 层级靠字重、留白和 1px 线，阴影只给浮起的东西。跟随系统浅色 / 深色。
 */

@font-face {
  font-family: "Inter Variable";
  font-style: normal;
  font-display: swap;
  font-weight: 100 900;
  src: url("assets/inter-latin-wght-normal.woff2") format("woff2-variations");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329,
    U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

/* ============ 令牌（与 app/src/styles.css 同值） ============ */
:root {
  --bg: #f3f5f8;
  --surface: #ffffff;
  --surface-2: #eef1f5;
  --line: #e2e7ee;
  --line-strong: #cbd3de;

  --fg: #0f172a;
  --fg-2: #475569;
  --fg-3: #64748b;

  --canvas: #e9edf3;
  --canvas-dot: rgba(15, 23, 42, 0.13);
  --canvas-fg: #1e293b;
  --canvas-fg-2: #526077;

  --accent: #1f63f0;
  --accent-fill: #1f63f0;
  --accent-hover: #1a54cf;
  --on-accent: #ffffff;
  --accent-soft: rgba(31, 99, 240, 0.1);
  --accent-glow: rgba(31, 99, 240, 0.28);

  --ok-dot: #16a34a;
  --warn: #b45309;
  --warn-soft: #fdf5e6;
  --warn-line: #f1d6a6;

  --shadow-float: 0 1px 2px rgba(15, 23, 42, 0.06), 0 16px 40px -12px rgba(15, 23, 42, 0.28);

  --h0-fill: #dcf2ec; --h0-line: #86cdbd; --h0-ink: #0d5a4e;
  --h1-fill: #faefd6; --h1-line: #e2bd70; --h1-ink: #744705;

  --sans: "Inter Variable", -apple-system, BlinkMacSystemFont, "PingFang SC", "Segoe UI Variable Text", "Segoe UI",
    "Microsoft YaHei UI", "Microsoft YaHei", sans-serif;

  --r-control: 6px;
  --r-group: 10px;
  --r-sheet: 14px;

  --t-fast: 120ms;
  --t-base: 200ms;
  --ease-out: cubic-bezier(0.2, 0.8, 0.2, 1);

  --gutter: 24px;
  --max: 1120px;

  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a101d;
    --surface: #0f172a;
    --surface-2: #172036;
    --line: #1e293d;
    --line-strong: #2d3a52;

    --fg: #f1f5f9;
    --fg-2: #a5b2c5;
    --fg-3: #8090a7;

    --canvas: #070c17;
    --canvas-dot: rgba(148, 163, 184, 0.16);
    --canvas-fg: #e2e8f0;
    --canvas-fg-2: #8b9ab0;

    --accent: #6b9bff;
    --accent-fill: #2f6bff;
    --accent-hover: #4a7fff;
    --accent-soft: rgba(107, 155, 255, 0.14);
    --accent-glow: rgba(107, 155, 255, 0.4);

    --ok-dot: #22c55e;
    --warn: #f5b04c;
    --warn-soft: rgba(245, 176, 76, 0.08);
    --warn-line: rgba(245, 176, 76, 0.28);

    --shadow-float: 0 0 0 1px var(--line-strong), 0 20px 48px -12px rgba(0, 0, 0, 0.75);

    --h0-fill: #0e2b29; --h0-line: #2a7568; --h0-ink: #93e2d1;
    --h1-fill: #2b2210; --h1-line: #846128; --h1-ink: #f3cf88;

    color-scheme: dark;
  }
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 72px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  font-variant-numeric: tabular-nums;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1,
h2,
h3,
p,
ol,
ul,
dl,
dd,
figure {
  margin: 0;
}

ol,
ul {
  padding: 0;
  list-style: none;
}

img {
  display: block;
}

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}

.wrap {
  width: 100%;
  max-width: calc(var(--max) + var(--gutter) * 2);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.sr {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.skip {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 100;
  padding: 8px 14px;
  border-radius: var(--r-control);
  background: var(--accent-fill);
  color: var(--on-accent);
  font-size: 14px;
  transition: top var(--t-fast);
}
.skip:focus {
  top: 12px;
}

.i {
  width: 20px;
  height: 20px;
  flex: none;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.75;
  stroke-linecap: round;
  stroke-linejoin: round;
}

kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 22px;
  height: 22px;
  margin: 0 2px;
  padding: 0 5px;
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: 5px;
  background: var(--surface);
  color: var(--fg);
  font: 500 12px/1 var(--sans);
  vertical-align: 1px;
}

.br-sm {
  display: none;
}

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 20px;
  border: 1px solid transparent;
  border-radius: var(--r-control);
  font-size: 15px;
  font-weight: 600;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color var(--t-fast), border-color var(--t-fast), color var(--t-fast);
}
.btn-sm {
  min-height: 36px;
  padding: 0 14px;
  font-size: 14px;
}
.btn-lg {
  min-height: 48px;
  padding: 0 22px;
  font-size: 16px;
}
.btn-primary {
  background: var(--accent-fill);
  color: var(--on-accent);
}
.btn-primary:hover {
  background: var(--accent-hover);
}
.btn-ghost {
  border-color: var(--line-strong);
  color: var(--fg);
}
.btn-ghost:hover {
  background: var(--surface);
}

/* ============ 顶栏 ============ */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg);
  border-bottom: 1px solid transparent;
  transition: border-color var(--t-base);
}
.nav.scrolled {
  border-bottom-color: var(--line);
}
.nav-row {
  display: flex;
  align-items: center;
  gap: 32px;
  height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.brand img {
  border-radius: 7px;
}
.brand-cn {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.brand-en {
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 500;
}

.nav-links {
  display: flex;
  gap: 4px;
  margin-left: auto;
}
.nav-links a {
  padding: 8px 12px;
  border-radius: var(--r-control);
  color: var(--fg-2);
  font-size: 14px;
  transition: color var(--t-fast), background-color var(--t-fast);
}
.nav-links a:hover {
  color: var(--fg);
  background: var(--surface-2);
}

/* ============ 首屏 ============ */
.hero {
  padding: 72px 0 96px;
}
.hero-copy {
  max-width: calc(780px + var(--gutter) * 2);
  margin-left: max(0px, calc((100% - var(--max) - var(--gutter) * 2) / 2));
}

.eyebrow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 24px;
  color: var(--fg-2);
  font-size: 14px;
}
.tag {
  padding: 2px 8px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: var(--surface);
  color: var(--fg);
  font-size: 12px;
  font-weight: 600;
}

h1 {
  font-size: clamp(40px, 7vw, 72px);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.lede {
  max-width: 40em;
  margin-top: 24px;
  color: var(--fg-2);
  font-size: 18px;
  line-height: 1.75;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 36px;
}
.cta-note {
  margin-top: 14px;
  color: var(--fg-3);
  font-size: 14px;
}
.cta-note a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ============ 演示 ============ */
.demo {
  margin-top: 64px;
  border: 1px solid var(--line);
  border-radius: var(--r-sheet);
  overflow: hidden;
  background: var(--surface);
}

.stage {
  position: relative;
  background-color: var(--canvas);
  background-image: radial-gradient(var(--canvas-dot) 1px, transparent 1.2px);
  background-size: 20px 20px;
  background-position: 10px 10px;
  touch-action: pan-y;
  user-select: none;
  -webkit-user-select: none;
  cursor: none;
  border-radius: var(--r-sheet) var(--r-sheet) 0 0;
}
.stage:has(.demo-input:focus-visible) {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}
/* 接收键盘和输入法的输入框：看不见，但可以聚焦 */
.demo-input {
  position: absolute;
  left: 0;
  top: 0;
  width: 1px;
  height: 1px;
  padding: 0;
  border: 0;
  opacity: 0;
  pointer-events: none;
}

.stage-inner {
  position: relative;
  aspect-ratio: 1000 / 520;
  max-width: 1000px;
  margin: 0 auto;
}

.screen {
  position: absolute;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--fill);
  border-color: var(--edge);
  color: var(--ink);
  transition: box-shadow var(--t-base) var(--ease-out), border-color var(--t-base);
}
.hue-0 {
  --fill: var(--h0-fill);
  --edge: var(--h0-line);
  --ink: var(--h0-ink);
}
.hue-1 {
  --fill: var(--h1-fill);
  --edge: var(--h1-line);
  --ink: var(--h1-ink);
}
.screen.active {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}

.screen-win {
  flex: 1;
  margin: 9% 10% 0;
  border: 1px solid var(--edge);
  border-bottom: 0;
  border-radius: 6px 6px 0 0;
  background: color-mix(in srgb, var(--fill) 55%, var(--surface));
  overflow: hidden;
}
.win-bar {
  display: flex;
  gap: 4px;
  padding: 7px 8px;
  border-bottom: 1px solid var(--edge);
}
.win-bar i {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--edge);
}
.win-text {
  padding: 8px 10px;
  min-height: 2.2em;
  font-size: clamp(10px, 1.5vw, 14px);
  font-weight: 500;
  line-height: 1.4;
  word-break: break-all;
}
.typed:empty::before {
  content: attr(data-placeholder);
  opacity: 0.55;
}
.caret {
  display: none;
  width: 1.5px;
  height: 1.1em;
  margin-left: 1px;
  vertical-align: -0.18em;
  background: var(--accent);
}
.screen.active .caret {
  display: inline-block;
  animation: blink 1.1s steps(1) infinite;
}
@keyframes blink {
  50% {
    opacity: 0;
  }
}

.screen-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 2px 8px;
  padding: 7px 10px 8px;
  border-top: 1px solid var(--edge);
}
.screen-name {
  font-size: clamp(11px, 1.5vw, 14px);
  font-weight: 600;
}
.screen-os {
  font-size: clamp(10px, 1.2vw, 12px);
  opacity: 0.8;
}

.pill {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 1px 8px;
  border-radius: 999px;
  background: var(--accent-fill);
  color: var(--on-accent);
  font-size: clamp(10px, 1.2vw, 12px);
  font-weight: 600;
  opacity: 0;
  transform: translateY(-2px);
  transition: opacity var(--t-fast), transform var(--t-fast);
}
.screen.active .pill {
  opacity: 1;
  transform: none;
}

/* 接缝：全页唯一带光晕的元素 */
.seam {
  position: absolute;
  width: 5px;
  margin-left: -2.5px;
  border-radius: 3px;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft), 0 0 14px var(--accent-glow);
}
.seam.flash {
  animation: seam-flash 520ms var(--ease-out);
}
@keyframes seam-flash {
  0% {
    box-shadow: 0 0 0 3px var(--accent-soft), 0 0 14px var(--accent-glow);
  }
  30% {
    box-shadow: 0 0 0 7px var(--accent-soft), 0 0 30px var(--accent-glow);
  }
  100% {
    box-shadow: 0 0 0 3px var(--accent-soft), 0 0 14px var(--accent-glow);
  }
}

.cursor {
  position: absolute;
  left: 0;
  top: 0;
  width: 24px;
  height: 24px;
  margin: -3px 0 0 -4px;
  pointer-events: none;
  will-change: transform;
}
.cursor svg {
  width: 100%;
  height: 100%;
  fill: var(--fg);
  stroke: var(--surface);
  stroke-width: 1.5;
  stroke-linejoin: round;
  filter: drop-shadow(0 1px 1.5px rgba(0, 0, 0, 0.25));
}

.dwell {
  position: absolute;
  left: 0;
  top: 0;
  width: 30px;
  height: 30px;
  margin: -15px 0 0 -15px;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--t-fast);
}
.dwell.on {
  opacity: 1;
}
.dwell svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}
.dwell circle {
  fill: none;
  stroke: var(--accent);
  stroke-width: 3;
  stroke-linecap: round;
  stroke-dasharray: 94.25;
  stroke-dashoffset: 94.25;
}
.dwell.run circle {
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 300ms linear;
}

.demo-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 28px;
  padding: 16px 20px;
  border-top: 1px solid var(--line);
  font-size: 14px;
}
.status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--fg-2);
  min-width: 13em;
}
.status b {
  color: var(--fg);
  font-weight: 600;
}
.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.switch {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  color: var(--fg-2);
  cursor: pointer;
}
.switch input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
}
.track {
  position: relative;
  width: 34px;
  height: 20px;
  border-radius: 999px;
  background: var(--line-strong);
  transition: background-color var(--t-fast);
}
.track::after {
  content: "";
  position: absolute;
  left: 2px;
  top: 2px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.25);
  transition: transform var(--t-fast) var(--ease-out);
}
.switch input:checked + .track {
  background: var(--accent-fill);
}
.switch input:checked + .track::after {
  transform: translateX(14px);
}
.switch input:focus-visible + .track {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.hint {
  flex: 1 1 360px;
  color: var(--fg-3);
  line-height: 1.9;
}
.hint kbd {
  height: 20px;
  min-width: 20px;
  font-size: 11px;
}
.seam-chip {
  display: inline-block;
  width: 3px;
  height: 14px;
  margin: 0 5px 0 4px;
  border-radius: 2px;
  background: var(--accent);
  vertical-align: -2px;
}

/* ============ 通用分节 ============ */
.section {
  padding: 112px 0;
  border-top: 1px solid var(--line);
}
.section-alt {
  background: var(--surface);
}

.section-head {
  max-width: 34em;
  margin-bottom: 56px;
}
.kicker {
  margin-bottom: 12px;
  color: var(--accent);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
}
h2 {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.005em;
  text-wrap: balance;
}
.section-head p:not(.kicker) {
  margin-top: 16px;
  color: var(--fg-2);
  font-size: 17px;
}

h3 {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.4;
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: 64px;
  align-items: start;
}
.split .section-head {
  margin-bottom: 0;
}

/* ============ 功能 ============ */
.features {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}
.features li {
  padding: 32px 28px 36px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.fi {
  width: 28px;
  height: 28px;
  margin-bottom: 20px;
  color: var(--fg);
  stroke-width: 1.5;
}
.fi .acc {
  stroke: var(--accent);
  stroke-width: 2.25;
}
.features p {
  margin-top: 10px;
  color: var(--fg-2);
  font-size: 15px;
  line-height: 1.75;
}

/* ============ 上手 ============ */
.steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 40px;
  counter-reset: s;
}
.steps li {
  position: relative;
  padding-top: 52px;
}
.steps li::before {
  content: "";
  position: absolute;
  top: 15px;
  left: 44px;
  right: -28px;
  height: 1px;
  background: var(--line-strong);
}
.steps li:last-child::before {
  display: none;
}
.step-no {
  position: absolute;
  top: 0;
  left: 0;
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: var(--surface);
  font-size: 14px;
  font-weight: 600;
}
.steps p {
  margin-top: 10px;
  color: var(--fg-2);
  font-size: 15px;
  line-height: 1.75;
}

.code {
  display: flex;
  gap: 6px;
  margin-top: 20px;
}
.code span {
  display: grid;
  place-items: center;
  width: 36px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: var(--r-control);
  background: var(--surface-2);
  font-size: 20px;
  font-weight: 600;
}
.code span:nth-child(3) {
  margin-right: 10px;
}

/* ============ 安全 ============ */
.p2p {
  position: relative;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 0;
  padding: 72px 28px 36px;
  border: 1px solid var(--line);
  border-radius: var(--r-group);
  background-color: var(--canvas);
  background-image: radial-gradient(var(--canvas-dot) 1px, transparent 1.2px);
  background-size: 20px 20px;
}
.node {
  padding: 10px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  background: var(--surface);
  color: var(--canvas-fg);
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
}
.wire {
  position: relative;
  height: 2px;
  background: var(--accent);
}
.lock {
  position: absolute;
  left: 50%;
  top: 50%;
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border: 1px solid var(--accent);
  border-radius: 50%;
  background: var(--surface);
  color: var(--accent);
  transform: translate(-50%, -50%);
}
.lock .i {
  width: 18px;
  height: 18px;
}
.cloud {
  position: absolute;
  top: 20px;
  left: 50%;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--canvas-fg-2);
  font-size: 13px;
  white-space: nowrap;
  transform: translateX(-50%);
}

.facts {
  margin-top: 32px;
}
.facts div {
  display: grid;
  grid-template-columns: 8.5em 1fr;
  gap: 16px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
}
.facts div:last-child {
  border-bottom: 1px solid var(--line);
}
.facts dt {
  font-weight: 600;
}
.facts dd {
  color: var(--fg-2);
  font-size: 15px;
}

/* ============ 手感 ============ */
.spec {
  width: 100%;
  border-collapse: collapse;
}
.spec th,
.spec td {
  padding: 18px 0;
  border-top: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}
.spec tr:last-child th,
.spec tr:last-child td {
  border-bottom: 1px solid var(--line);
}
.spec th {
  width: 8.5em;
  padding-right: 16px;
  font-weight: 600;
}
.spec td {
  color: var(--fg-2);
  font-size: 15px;
}
.num {
  color: var(--fg);
  font-weight: 600;
  white-space: nowrap;
}

/* ============ 下载 ============ */
.dl {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}
.dl-card {
  display: flex;
  align-items: center;
  gap: 18px;
  min-height: 96px;
  padding: 20px 24px;
  border: 1px solid var(--line);
  border-radius: var(--r-group);
  background: var(--surface);
  transition: border-color var(--t-fast);
}
.dl-card:hover {
  border-color: var(--line-strong);
}
.dl-card.recommended {
  border-color: var(--accent);
}
.dl-icon {
  width: 32px;
  height: 32px;
  stroke-width: 1.5;
}
.dl-body {
  display: flex;
  flex: 1;
  flex-direction: column;
  min-width: 0;
}
.dl-title {
  font-size: 18px;
  font-weight: 600;
}
.dl-meta {
  color: var(--fg-3);
  font-size: 14px;
}
.dl-go {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 40px;
  padding: 0 14px;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-control);
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
  transition: background-color var(--t-fast), color var(--t-fast), border-color var(--t-fast);
}
.dl-go .i {
  width: 16px;
  height: 16px;
}
.dl-card.recommended .dl-go {
  border-color: transparent;
  background: var(--accent-fill);
  color: var(--on-accent);
}
.dl-card:hover .dl-go {
  background: var(--surface-2);
}
.dl-card.recommended:hover .dl-go {
  background: var(--accent-hover);
}
.rec-label {
  margin-left: 8px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 600;
}

.notice {
  display: flex;
  gap: 12px;
  margin-top: 24px;
  padding: 14px 16px;
  border: 1px solid var(--warn-line);
  border-radius: var(--r-group);
  background: var(--warn-soft);
  color: var(--fg-2);
  font-size: 14px;
}
.notice .i {
  margin-top: 2px;
  color: var(--warn);
}

/* ============ 常见问题 ============ */
.faq details {
  border-top: 1px solid var(--line);
}
.faq details:last-child {
  border-bottom: 1px solid var(--line);
}
.faq summary {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 60px;
  padding: 14px 40px 14px 0;
  font-weight: 600;
  list-style: none;
  cursor: pointer;
  transition: color var(--t-fast);
}
.faq summary::-webkit-details-marker {
  display: none;
}
.faq summary::after {
  content: "";
  position: absolute;
  right: 6px;
  top: 50%;
  width: 9px;
  height: 9px;
  margin-top: -7px;
  border-right: 1.75px solid var(--fg-3);
  border-bottom: 1.75px solid var(--fg-3);
  transform: rotate(45deg);
  transition: transform var(--t-base) var(--ease-out);
}
.faq details[open] summary::after {
  margin-top: -2px;
  transform: rotate(225deg);
}
.faq summary:hover {
  color: var(--accent);
}
.faq details p {
  padding: 0 40px 22px 0;
  color: var(--fg-2);
  font-size: 15px;
  line-height: 1.8;
}

/* ============ 收尾与页脚 ============ */
.final {
  padding: 96px 0;
  border-top: 1px solid var(--line);
  background-color: var(--canvas);
  background-image: radial-gradient(var(--canvas-dot) 1px, transparent 1.2px);
  background-size: 20px 20px;
}
.final-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}
.final h2 {
  color: var(--canvas-fg);
}

.foot {
  border-top: 1px solid var(--line);
  padding: 32px 0 40px;
  color: var(--fg-3);
  font-size: 14px;
}
.foot-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 24px;
}
.brand-foot .brand-cn {
  color: var(--fg);
  font-size: 15px;
}
.brand-foot img {
  border-radius: 5px;
}
.foot-links {
  display: flex;
  gap: 4px;
  margin-left: auto;
}
.foot-links a {
  padding: 10px;
  transition: color var(--t-fast);
}
.foot-links a:hover {
  color: var(--fg);
}

/* ============ 响应式 ============ */
@media (max-width: 960px) {
  .split {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .features {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  :root {
    --gutter: 16px;
  }
  .nav-links {
    display: none;
  }
  .nav-row {
    justify-content: space-between;
  }
  .hero {
    padding: 48px 0 64px;
  }
  .br-sm {
    display: inline;
  }
  .lede {
    font-size: 16px;
  }
  .cta-row .btn {
    flex: 1 1 auto;
  }
  .demo {
    margin-top: 40px;
    margin-left: calc(var(--gutter) * -1);
    margin-right: calc(var(--gutter) * -1);
    border-radius: 0;
    border-left: 0;
    border-right: 0;
  }
  .stage {
    border-radius: 0;
  }
  .stage-inner {
    aspect-ratio: 1000 / 640;
  }
  .screen-win {
    margin: 7% 7% 0;
  }
  .win-bar {
    padding: 5px 6px;
  }
  .win-text {
    padding: 4px 6px;
  }
  .screen-os {
    display: none;
  }
  .screen-foot {
    padding: 4px 6px;
  }
  .pill {
    top: 4px;
    right: 4px;
    padding: 0 6px;
  }
  .demo-bar {
    padding: 14px 16px;
  }
  .section {
    padding: 72px 0;
  }
  .section-head {
    margin-bottom: 36px;
  }
  .features {
    grid-template-columns: 1fr;
  }
  .features li {
    padding: 24px 20px 28px;
  }
  .steps {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .steps li {
    padding: 0 0 0 52px;
  }
  .steps li::before {
    top: 40px;
    bottom: -24px;
    left: 15.5px;
    right: auto;
    width: 1px;
    height: auto;
  }
  .p2p {
    padding: 64px 16px 28px;
  }
  .node {
    padding: 8px 10px;
    font-size: 13px;
  }
  .facts div {
    grid-template-columns: 1fr;
    gap: 4px;
  }
  .spec th,
  .spec td {
    display: block;
    width: auto;
    padding: 0;
    border: 0;
  }
  .spec tr {
    display: block;
    padding: 16px 0;
    border-top: 1px solid var(--line);
  }
  .spec tr:last-child {
    border-bottom: 1px solid var(--line);
  }
  .spec tr:last-child th,
  .spec tr:last-child td {
    border: 0;
  }
  .spec td {
    margin-top: 4px;
  }
  .dl {
    grid-template-columns: 1fr;
  }
  .dl-card {
    padding: 16px;
    gap: 14px;
  }
  .final {
    padding: 72px 0;
  }
  .final .btn {
    width: 100%;
  }
  .foot-links {
    margin-left: -10px;
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* 触屏：系统光标不存在，演示里的光标照常显示 */
@media (hover: none) {
  .stage {
    cursor: auto;
  }
}