/* FlashVPN 官网样式 —— 浅色白黄商务风
 *
 * 配色直接取自 App 图标 (flutter/assets/icons/logo.png):
 *   --accent   #F08519  图标主橙黄
 *   --accent-2 #FFB259  图标高光黄
 *   --ink      #332C2B  图标深棕（正文/标题）
 */

:root {
  --bg: #ffffff;
  --bg-soft: #fdf8f1;
  --surface: #ffffff;
  --surface-alt: #fbf6ee;
  --line: rgba(51, 44, 43, 0.1);
  --line-strong: rgba(51, 44, 43, 0.18);
  --text: #241f1e;
  --text-soft: #5b514d;
  --text-muted: #8b807a;
  --accent: #f08519;
  --accent-2: #ffb259;
  --accent-deep: #c96a08;
  --accent-soft: rgba(240, 133, 25, 0.1);
  --accent-softer: rgba(240, 133, 25, 0.05);
  --white: #ffffff;
  --ink: #332c2b;
  --radius-sm: 12px;
  --radius-md: 18px;
  --radius-lg: 26px;
  --container: 1200px;
  --header-height: 78px;
  --shadow-sm: 0 1px 4px rgba(51, 44, 43, 0.05);
  --shadow-md: 0 8px 22px rgba(51, 44, 43, 0.08);
  --shadow-lg: 0 18px 40px rgba(51, 44, 43, 0.12);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 24px);
}

body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  /* 背景渐变直接画在 body 上：静态、一次栅格化，滚动时零重绘。
     之前的 .page-glow 用 filter: blur() 做光晕，每帧都要重新模糊，
     是滚动掉帧的主要来源，已全部移除。 */
  background:
    radial-gradient(900px 520px at 82% -6%, rgba(240, 133, 25, 0.11), transparent 60%),
    radial-gradient(760px 480px at 4% 2%, rgba(255, 178, 89, 0.1), transparent 58%),
    var(--bg);
  background-attachment: scroll;
  color: var(--text);
  font-family: "Inter", "Segoe UI", "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ---------- 滚动性能基线 ----------
 *
 * 1. 大面积光晕一律用静态 radial-gradient，不使用 filter: blur()。
 *    blur 是逐帧滤镜，滚动时整块区域要重新合成，是掉帧的主要来源。
 * 2. 提升到合成层的元素只做 transform / opacity 动画，
 *    不碰 width / height / top / left，避免每帧触发 layout。
 * 3. 阴影半径收紧，减少大面积重绘区域。
 */

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

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

button {
  font: inherit;
  color: inherit;
}

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

h1,
h2,
h3,
p {
  margin: 0;
}

::selection {
  background: rgba(240, 133, 25, 0.22);
  color: var(--ink);
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  padding: 10px 18px;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  transform: translateY(-160%);
  transition: transform 0.25s var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
}

/* ---------- Fonts ---------- */

@font-face {
  font-family: "Inter";
  src: url("./fonts/Inter-Regular.ttf") format("truetype");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Inter";
  src: url("./fonts/Inter-Medium.ttf") format("truetype");
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Inter";
  src: url("./fonts/Inter-SemiBold.ttf") format("truetype");
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Inter";
  src: url("./fonts/Inter-Bold.ttf") format("truetype");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

/* ---------- Header ---------- */

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
  border-bottom: 1px solid transparent;
  /* 不用 will-change: transform —— 它会给内部 position:fixed 的
     移动端导航创建新的包含块，导致菜单相对 header 定位而不是视口。
     position:fixed 本身已经足以让浏览器把它留在合成层上。 */
  transition: background 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.site-header.is-scrolled {
  /* 不用 backdrop-filter —— 实时背景模糊要在每帧重新采样并模糊整个
     header 背后的内容，是滚动掉帧的元凶。改成不透明度足够的纯色，
     视觉几乎一致，代价接近于零。 */
  background: rgba(255, 255, 255, 0.94);
  border-bottom-color: var(--line);
  box-shadow: 0 4px 16px rgba(51, 44, 43, 0.05);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  flex-shrink: 0;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 13px;
  background: var(--white);
  border: 1px solid rgba(240, 133, 25, 0.22);
  box-shadow: 0 6px 18px rgba(240, 133, 25, 0.14);
  overflow: hidden;
}

.brand-mark img {
  width: 36px;
  height: 36px;
  object-fit: contain;
}

.brand-name {
  font-size: 1.16rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.brand-name span {
  color: var(--accent);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 30px;
  margin-left: auto;
}

/* 移动端抽屉的展开态。桌面端不需要，这里保持一份基础规则，
 * 避免 .nav-links.is-open 只存在于 media query 里。 */
.nav-links.is-open {
  transform: translateY(0);
}

.nav-links a {
  position: relative;
  font-size: 0.92rem;
  color: var(--text-soft);
  transition: color 0.22s ease;
}

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: -7px;
  height: 2px;
  border-radius: 2px;
  background: var(--accent);
  transition: right 0.3s var(--ease);
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--ink);
}

.nav-links a:hover::after,
.nav-links a:focus-visible::after {
  right: 0;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid var(--line-strong);
  border-radius: 11px;
  background: rgba(255, 255, 255, 0.7);
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  width: 17px;
  height: 1.5px;
  margin: 4px auto;
  border-radius: 2px;
  background: var(--ink);
  transition: transform 0.28s var(--ease), opacity 0.2s ease;
}

.menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(5.5px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-5.5px) rotate(-45deg);
}

/* ---------- Buttons ---------- */

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 0.94rem;
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
  cursor: pointer;
  transition: transform 0.24s var(--ease), box-shadow 0.24s ease, background 0.24s ease, border-color 0.24s ease, color 0.24s ease;
}

.button svg {
  width: 17px;
  height: 17px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.button--primary {
  background: linear-gradient(135deg, var(--accent-2), var(--accent));
  color: #fff;
  box-shadow: 0 12px 30px rgba(240, 133, 25, 0.3);
}

.button--primary:hover,
.button--primary:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 18px 40px rgba(240, 133, 25, 0.4);
}

.button--secondary {
  background: var(--white);
  border-color: var(--line-strong);
  color: var(--ink);
  box-shadow: var(--shadow-sm);
}

.button--secondary:hover,
.button--secondary:focus-visible {
  transform: translateY(-2px);
  border-color: rgba(240, 133, 25, 0.45);
  background: var(--accent-softer);
  box-shadow: var(--shadow-md);
}

.button--ghost {
  color: var(--text-soft);
}

.button--ghost:hover,
.button--ghost:focus-visible {
  color: var(--ink);
  background: var(--accent-softer);
}

.button--ghost svg {
  fill: currentColor;
  stroke: none;
}

.button--light {
  background: var(--white);
  color: var(--ink);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.18);
}

.button--light:hover,
.button--light:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.24);
}

.button--light svg {
  fill: currentColor;
  stroke: none;
}

.button--soon {
  background: rgba(255, 178, 89, 0.14);
  border-color: rgba(240, 133, 25, 0.34);
  color: var(--accent-deep);
}

.button--soon:hover,
.button--soon:focus-visible {
  transform: translateY(-2px);
  background: rgba(255, 178, 89, 0.24);
  border-color: rgba(240, 133, 25, 0.5);
}

.button--small {
  padding: 9px 16px;
  font-size: 0.88rem;
}

.button--large {
  padding: 15px 28px;
  font-size: 0.98rem;
}

.button--full {
  width: 100%;
  margin-top: auto;
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  padding: calc(var(--header-height) + 84px) 0 44px;
  overflow: hidden;
  /* 首屏内容始终参与渲染，不做视口外跳过 */
}

/* ---------- Layout ---------- */

/* 所有区块的统一水平留白容器。
 * 宽度上限 1200px，两侧保留 48px 安全边距（窄屏收到 32px），
 * 保证内容不会贴到视口边缘。 */
.container {
  width: min(100% - 96px, var(--container));
  margin-inline: auto;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
  align-items: center;
  gap: 64px;
}

.hero-copy {
  position: relative;
  z-index: 1;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 7px 15px;
  border: 1px solid rgba(240, 133, 25, 0.28);
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-deep);
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.04em;
}

.eyebrow-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(240, 133, 25, 0.16);
}

.hero h1 {
  margin-top: 24px;
  font-size: clamp(2.6rem, 5.2vw, 4.15rem);
  line-height: 1.13;
  letter-spacing: -0.035em;
  font-weight: 700;
  color: var(--ink);
}

.hero h1 span,
.section-heading h2 span,
.how-copy h2 span,
.contact-content h2 span {
  background: linear-gradient(120deg, var(--accent-2) 6%, var(--accent) 52%, var(--accent-deep) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lead {
  max-width: 560px;
  margin-top: 22px;
  color: var(--text-soft);
  font-size: 1.06rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 13px;
  margin-top: 34px;
}

.platform-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 34px;
}

.platform-pills span {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--white);
  color: var(--text-soft);
  font-size: 0.84rem;
  box-shadow: var(--shadow-sm);
}

.platform-pills svg {
  width: 15px;
  height: 15px;
  fill: currentColor;
  stroke: none;
}

.platform-pills .is-soon {
  color: var(--accent-deep);
  border-color: rgba(240, 133, 25, 0.3);
  background: var(--accent-softer);
}

/* Hero visual */

.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  padding: 30px 0;
}

.visual-halo {
  position: absolute;
  inset: 2% 4%;
  border-radius: 50%;
  /* 静态渐变代替 blur(26px)：光晕在滚动中保持不变，无需逐帧重算 */
  background: radial-gradient(circle, rgba(240, 133, 25, 0.18) 0%, rgba(255, 178, 89, 0.08) 52%, rgba(255, 255, 255, 0) 72%);
}

.device {
  position: relative;
  z-index: 2;
  width: min(100%, 470px);
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
  background: linear-gradient(170deg, #ffffff, #fdf6ec);
  box-shadow:
    0 24px 48px rgba(51, 44, 43, 0.13),
    0 2px 0 #fff inset,
    0 0 0 1px rgba(255, 255, 255, 0.7) inset;
  overflow: hidden;
}

.device-topbar {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 20px;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.86);
  color: var(--text-muted);
  font-size: 0.76rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.window-dots {
  display: flex;
  gap: 6px;
}

.window-dots i {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: rgba(51, 44, 43, 0.14);
}

.window-dots i:first-child {
  background: rgba(240, 133, 25, 0.55);
}

.window-dots i:nth-child(2) {
  background: rgba(255, 178, 89, 0.6);
}

.window-dots i:nth-child(3) {
  background: rgba(51, 44, 43, 0.16);
}

.device-topbar > span {
  flex: 1;
}

.device-logo {
  width: 18px;
  height: 18px;
  object-fit: contain;
  border-radius: 5px;
}

.device-topbar svg {
  width: 15px;
  height: 15px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.device-content {
  padding: 30px 28px 26px;
}

.mock-status {
  text-align: center;
}

.mock-orbit {
  display: grid;
  place-items: center;
  width: 138px;
  height: 138px;
  margin: 0 auto 18px;
  border-radius: 50%;
  border: 1px solid rgba(240, 133, 25, 0.3);
  background: radial-gradient(circle, rgba(255, 178, 89, 0.22), transparent 64%);
  box-shadow: 0 0 28px rgba(240, 133, 25, 0.16);
  position: relative;
}

.mock-orbit::before,
.mock-orbit::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  border: 1px solid rgba(240, 133, 25, 0.2);
}

.mock-orbit::before {
  inset: 13px;
}

.mock-orbit::after {
  inset: 26px;
  border-color: rgba(51, 44, 43, 0.1);
}

.mock-power {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  width: 66px;
  height: 66px;
  border-radius: 50%;
  background: linear-gradient(140deg, var(--accent-2), var(--accent));
  box-shadow: 0 10px 26px rgba(240, 133, 25, 0.42);
}

.mock-power svg {
  width: 28px;
  height: 28px;
  fill: none;
  stroke: #fff;
  stroke-width: 2;
  stroke-linecap: round;
}

.mock-kicker {
  color: var(--text-muted);
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.mock-status h3 {
  margin-top: 4px;
  font-size: 1.42rem;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.mock-server {
  margin-top: 6px;
  color: var(--text-soft);
  font-size: 0.88rem;
}

.mock-server span {
  color: var(--text-muted);
  margin-inline: 4px;
}

.mock-stats {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  align-items: center;
  gap: 10px;
  margin-top: 26px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--white);
  box-shadow: var(--shadow-sm);
  text-align: center;
}

.mock-stats div {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.mock-stats span {
  color: var(--text-muted);
  font-size: 0.72rem;
}

.mock-stats strong {
  font-size: 1.02rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.mock-stats small {
  color: var(--text-muted);
  font-size: 0.66rem;
  font-weight: 500;
}

.mock-stats > i {
  width: 1px;
  height: 26px;
  background: var(--line);
}

.mock-chart {
  margin-top: 18px;
  padding: 16px 18px 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--white);
  box-shadow: var(--shadow-sm);
}

.mock-chart-label {
  display: flex;
  justify-content: space-between;
  color: var(--text-muted);
  font-size: 0.74rem;
}

.mock-chart svg {
  width: 100%;
  height: 92px;
  margin-top: 8px;
}

.chart-area {
  fill: url(#areaGradient);
}

.chart-line {
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}

.floating-card {
  position: absolute;
  z-index: 3;
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 12px 16px;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.97);
  box-shadow: var(--shadow-md);
  /* 去掉 backdrop-filter：两个持续做 float 动画的小卡片带着实时背景模糊，
     会让它们在滚动时不断重新采样+模糊背后的内容。改为不透明底色。 */
  animation: float 6s ease-in-out infinite;
}

.floating-card small {
  display: block;
  color: var(--text-muted);
  font-size: 0.7rem;
  line-height: 1.3;
}

.floating-card strong {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink);
}

.floating-icon {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent-deep);
}

.floating-icon--green {
  background: rgba(240, 133, 25, 0.16);
  color: var(--accent);
}

.floating-icon svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.floating-card--latency {
  top: 2px;
  right: -14px;
}

.floating-card--security {
  bottom: 6px;
  left: -20px;
  animation-delay: -3s;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-9px); }
}

/* 悬浮卡片离开视口后停掉动画：持续运行的 keyframes 会让浏览器
 * 每帧重新合成这两块区域，即使它们根本不在屏幕上。 */
.floating-card.is-idle {
  animation-play-state: paused;
}

.hero-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin-top: 68px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.hero-foot-label {
  color: var(--text-muted);
  font-size: 0.84rem;
  letter-spacing: 0.04em;
}

.hero-foot-items {
  display: flex;
  flex-wrap: wrap;
  gap: 26px;
}

.hero-foot-items span {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text-soft);
  font-size: 0.88rem;
}

.hero-foot-items i {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px rgba(240, 133, 25, 0.16);
}

/* ---------- Metrics ---------- */

.metrics {
  padding: 54px 0;
  border-block: 1px solid var(--line);
  background: linear-gradient(180deg, var(--bg-soft), rgba(255, 255, 255, 0));
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
}

.metric {
  text-align: center;
}

.metric strong {
  display: block;
  font-size: clamp(2rem, 3.4vw, 2.75rem);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 1.1;
  background: linear-gradient(140deg, var(--accent-2), var(--accent-deep));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.metric strong span {
  font-size: 0.45em;
  margin-left: 3px;
  color: var(--accent);
  -webkit-text-fill-color: currentColor;
}

.metric p {
  margin-top: 6px;
  color: var(--text-muted);
  font-size: 0.88rem;
}

/* ---------- Sections ---------- */

.section {
  position: relative;
  padding: 116px 0;
  /* 不用 content-visibility:auto —— 实测它会让文档高度在滚动过程中
     从 6981px 收缩到 5349px，产生 127~167px 的滚动位置跳动，
     反而比省下的渲染开销更影响手感。
     页面总高只有 ~5300px，不值得引入这种不稳定性。 */
}

.section-heading {
  max-width: 660px;
  margin-bottom: 56px;
}

.section-heading--center {
  margin-inline: auto;
  text-align: center;
}

.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--accent-deep);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.section-kicker::before {
  content: "";
  width: 22px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  opacity: 0.6;
}

.section-heading h2,
.how-copy h2 {
  margin-top: 14px;
  font-size: clamp(1.9rem, 3.6vw, 2.8rem);
  line-height: 1.25;
  letter-spacing: -0.03em;
  font-weight: 700;
  color: var(--ink);
}

.section-heading p,
.how-copy > p {
  margin-top: 16px;
  color: var(--text-soft);
  font-size: 1.02rem;
}

.section-heading--center p {
  max-width: 580px;
  margin-inline: auto;
}

/* ---------- Features ---------- */

.features {
  background:
    radial-gradient(760px 440px at 86% 6%, rgba(240, 133, 25, 0.08), transparent 62%);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  position: relative;
  padding: 32px 30px 34px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--white);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: transform 0.3s var(--ease), border-color 0.3s ease, box-shadow 0.3s ease;
}

.feature-card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(340px 180px at 18% 0%, rgba(255, 178, 89, 0.16), transparent 70%);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: rgba(240, 133, 25, 0.34);
  box-shadow: var(--shadow-lg);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-icon {
  position: relative;
  display: grid;
  place-items: center;
  width: 50px;
  height: 50px;
  border-radius: 14px;
  background: var(--accent-soft);
  border: 1px solid rgba(240, 133, 25, 0.22);
  color: var(--accent-deep);
}

.feature-icon svg {
  width: 23px;
  height: 23px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.feature-card h3 {
  position: relative;
  margin-top: 22px;
  font-size: 1.16rem;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.feature-card p {
  position: relative;
  margin-top: 10px;
  color: var(--text-soft);
  font-size: 0.94rem;
}

.feature-index {
  position: absolute;
  top: 30px;
  right: 28px;
  color: rgba(51, 44, 43, 0.14);
  font-size: 0.86rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

/* ---------- Download ---------- */

.download-section {
  overflow: hidden;
  background:
    linear-gradient(180deg, rgba(253, 248, 241, 0) 0%, var(--bg-soft) 100%);
}

.download-orb {
  position: absolute;
  top: -220px;
  left: 50%;
  width: 900px;
  height: 620px;
  transform: translateX(-50%);
  border-radius: 50%;
  /* 静态渐变代替 blur(40px) */
  background: radial-gradient(circle, rgba(255, 178, 89, 0.26) 0%, rgba(255, 178, 89, 0.08) 45%, rgba(255, 255, 255, 0) 68%);
  pointer-events: none;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
  align-items: stretch;
}

.download-card {
  display: flex;
  flex-direction: column;
  padding: 32px 30px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--white);
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s var(--ease), border-color 0.3s ease, box-shadow 0.3s ease;
}

.download-card:hover {
  transform: translateY(-6px);
  border-color: rgba(240, 133, 25, 0.34);
  box-shadow: var(--shadow-lg);
}

.download-card--featured {
  border-color: rgba(240, 133, 25, 0.38);
  box-shadow: 0 14px 34px rgba(240, 133, 25, 0.16);
}

.download-card--soon {
  background: linear-gradient(170deg, #fffdfa, var(--bg-soft));
}

.download-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.platform-icon {
  display: grid;
  place-items: center;
  width: 54px;
  height: 54px;
  border-radius: 15px;
}

.platform-icon svg {
  width: 26px;
  height: 26px;
  fill: currentColor;
  stroke: none;
}

.platform-icon--windows {
  background: var(--accent-soft);
  border: 1px solid rgba(240, 133, 25, 0.24);
  color: var(--accent-deep);
}

.platform-icon--android {
  background: rgba(255, 178, 89, 0.18);
  border: 1px solid rgba(240, 133, 25, 0.22);
  color: var(--accent);
}

.platform-icon--ios {
  background: rgba(51, 44, 43, 0.04);
  border: 1px solid var(--line);
  color: var(--text-soft);
}

.download-badge {
  padding: 5px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  border: 1px solid rgba(240, 133, 25, 0.26);
  color: var(--accent-deep);
  font-size: 0.76rem;
  font-weight: 600;
}

.download-badge--muted {
  background: rgba(255, 178, 89, 0.2);
  border-color: rgba(240, 133, 25, 0.24);
  color: var(--accent-deep);
}

.download-badge--soon {
  background: rgba(51, 44, 43, 0.05);
  border-color: var(--line-strong);
  color: var(--text-soft);
}

.platform-label {
  margin-top: 22px;
  color: var(--accent-deep);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.download-card h3 {
  margin-top: 7px;
  font-size: 1.42rem;
  letter-spacing: -0.025em;
  color: var(--ink);
}

.platform-desc {
  margin-top: 12px;
  color: var(--text-soft);
  font-size: 0.93rem;
}

.platform-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
  margin-bottom: 26px;
}

.platform-meta li {
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--bg-soft);
  color: var(--text-muted);
  font-size: 0.76rem;
}

.soon-note {
  margin-top: 12px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
}

.download-note {
  margin-top: 34px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.download-note a {
  color: var(--accent-deep);
  border-bottom: 1px solid rgba(240, 133, 25, 0.4);
}

.download-note a:hover {
  color: var(--accent);
}

/* ---------- How it works ---------- */

.how-section {
  border-top: 1px solid var(--line);
}

.how-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 70px;
  align-items: center;
}

.how-copy .text-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 26px;
  color: var(--accent-deep);
  font-weight: 600;
  font-size: 0.94rem;
}

.text-link svg {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition: transform 0.25s var(--ease);
}

.text-link:hover svg {
  transform: translateX(4px);
}

.steps {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.steps li {
  display: flex;
  gap: 22px;
  padding: 26px 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--white);
  box-shadow: var(--shadow-sm);
  transition: transform 0.28s var(--ease), border-color 0.28s ease, box-shadow 0.28s ease;
}

.steps li:hover {
  transform: translateX(6px);
  border-color: rgba(240, 133, 25, 0.3);
  box-shadow: var(--shadow-md);
}

.step-number {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: var(--accent-soft);
  border: 1px solid rgba(240, 133, 25, 0.22);
  color: var(--accent-deep);
  font-size: 0.84rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.steps h3 {
  font-size: 1.08rem;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.steps p {
  margin-top: 7px;
  color: var(--text-soft);
  font-size: 0.93rem;
}

/* ---------- FAQ ---------- */

.faq-section {
  border-top: 1px solid var(--line);
  background: var(--bg-soft);
}

.faq-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.72fr) minmax(0, 1.28fr);
  gap: 70px;
  align-items: start;
}

.faq-intro h2 {
  margin-top: 14px;
  font-size: clamp(1.8rem, 3.2vw, 2.5rem);
  letter-spacing: -0.03em;
  line-height: 1.25;
  color: var(--ink);
}

.faq-intro p {
  margin-top: 16px;
  color: var(--text-soft);
  font-size: 0.98rem;
}

.faq-intro .button {
  margin-top: 26px;
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--white);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: border-color 0.28s ease, box-shadow 0.28s ease;
}

.faq-item[open] {
  border-color: rgba(240, 133, 25, 0.34);
  box-shadow: var(--shadow-md);
}

.faq-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 21px 24px;
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
  color: var(--ink);
  list-style: none;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary span {
  position: relative;
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1px solid var(--line-strong);
  transition: transform 0.3s var(--ease), border-color 0.3s ease, background 0.3s ease;
}

.faq-item summary span::before,
.faq-item summary span::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 9px;
  height: 1.5px;
  background: var(--text-soft);
  transform: translate(-50%, -50%);
  transition: opacity 0.25s ease;
}

.faq-item summary span::after {
  transform: translate(-50%, -50%) rotate(90deg);
}

.faq-item[open] summary span {
  transform: rotate(180deg);
  border-color: rgba(240, 133, 25, 0.5);
  background: var(--accent-soft);
}

.faq-item[open] summary span::after {
  opacity: 0;
}

.faq-answer {
  padding: 0 24px 22px;
  color: var(--text-soft);
  font-size: 0.94rem;
  animation: fade-in 0.32s var(--ease);
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- Contact ---------- */

.contact-section {
  border-top: 1px solid var(--line);
}

.contact-card {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: 56px;
  padding: 64px 58px;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(240, 133, 25, 0.28);
  background: linear-gradient(140deg, #fffdf9 0%, #fdf3e6 55%, #fff 100%);
  box-shadow: 0 20px 46px rgba(51, 44, 43, 0.1);
  overflow: hidden;
}

.contact-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(51, 44, 43, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(51, 44, 43, 0.05) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(circle at 22% 42%, #000 0%, transparent 68%);
  -webkit-mask-image: radial-gradient(circle at 22% 42%, #000 0%, transparent 68%);
  pointer-events: none;
}

.contact-orb {
  position: absolute;
  border-radius: 50%;
  /* 静态渐变代替 blur(70px)：两张 380px 的模糊层每帧重算是明显的滚动开销 */
  pointer-events: none;
}

.contact-orb--one {
  top: -140px;
  right: -60px;
  width: 380px;
  height: 380px;
  background: radial-gradient(circle, rgba(255, 178, 89, 0.38) 0%, rgba(255, 178, 89, 0.12) 48%, rgba(255, 255, 255, 0) 72%);
}

.contact-orb--two {
  bottom: -170px;
  left: 26%;
  width: 340px;
  height: 340px;
  background: radial-gradient(circle, rgba(240, 133, 25, 0.16) 0%, rgba(240, 133, 25, 0.04) 48%, rgba(255, 255, 255, 0) 72%);
}

.contact-content,
.contact-channels {
  position: relative;
  z-index: 1;
}

.section-kicker--light {
  color: var(--accent-deep);
}

.contact-content h2 {
  margin-top: 14px;
  font-size: clamp(1.9rem, 3.6vw, 2.75rem);
  line-height: 1.24;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.contact-content p {
  max-width: 480px;
  margin-top: 16px;
  color: var(--text-soft);
  font-size: 1rem;
}

.contact-content .button {
  margin-top: 30px;
}

.contact-channels {
  display: flex;
  flex-direction: column;
  gap: 12px;
  justify-content: center;
}

.contact-channel {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 18px 20px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.82);
  box-shadow: var(--shadow-sm);
  transition: transform 0.28s var(--ease), border-color 0.28s ease, background 0.28s ease;
}

.contact-channel:hover {
  transform: translateX(5px);
  border-color: rgba(240, 133, 25, 0.34);
  background: #fff;
}

.contact-channel > span {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  flex-shrink: 0;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent-deep);
  font-size: 0.78rem;
  font-weight: 700;
}

.contact-channel div {
  flex: 1;
}

.contact-channel strong {
  display: block;
  font-size: 0.98rem;
  color: var(--ink);
}

.contact-channel p {
  color: var(--text-muted);
  font-size: 0.84rem;
}

.contact-channel svg {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: var(--text-muted);
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg-soft);
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
  gap: 60px;
  padding: 62px 0 44px;
}

.footer-brand p {
  margin-top: 16px;
  max-width: 280px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.footer-links h3 {
  margin-bottom: 16px;
  color: var(--ink);
  font-size: 0.9rem;
  letter-spacing: 0.04em;
}

.footer-links a {
  display: block;
  margin-bottom: 9px;
  color: var(--text-muted);
  font-size: 0.88rem;
  transition: color 0.22s ease, transform 0.22s ease;
}

.footer-links a:hover {
  color: var(--accent-deep);
  transform: translateX(3px);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 22px 0 28px;
  border-top: 1px solid var(--line);
  color: var(--text-muted);
  font-size: 0.82rem;
}

/* ---------- Telegram FAB ---------- */

.telegram-fab {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 90;
  display: grid;
  place-items: center;
  width: 54px;
  height: 54px;
  border-radius: 50%;
  background: linear-gradient(140deg, #35a9e8, #1f7fc4);
  color: #fff;
  box-shadow: 0 14px 32px rgba(31, 127, 196, 0.4);
  transition: transform 0.26s var(--ease), box-shadow 0.26s ease;
}

.telegram-fab svg {
  width: 25px;
  height: 25px;
  fill: currentColor;
}

.telegram-fab:hover,
.telegram-fab:focus-visible {
  transform: translateY(-4px) scale(1.04);
  box-shadow: 0 18px 40px rgba(31, 127, 196, 0.52);
}

/* ---------- Reveal animation ---------- */

[data-reveal] {
  opacity: 0;
  transform: translateY(22px);
  /* 只动 opacity / transform —— 两者都在合成层上完成，不触发 layout/paint。
   * will-change 由 script.js 在动画开始前临时挂上、结束后撤掉，
   * 避免一次性给几十个元素建图层。 */
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}

/* ---------- Responsive ---------- */

@media (max-width: 1080px) {
  .hero-grid {
    gap: 44px;
  }

  .floating-card--latency {
    right: -4px;
  }

  .floating-card--security {
    left: -6px;
  }

  .contact-card {
    padding: 52px 44px;
    gap: 44px;
  }
}

@media (max-width: 960px) {
  :root {
    --header-height: 70px;
  }

  .nav-links {
    position: fixed;
    inset: var(--header-height) 0 auto;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px 24px 26px;
    background: rgba(255, 255, 255, 0.99);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 20px 40px rgba(51, 44, 43, 0.08);
    transform: translateY(-140%);
    transition: transform 0.36s var(--ease);
  }

  .nav-links.is-open {
    transform: translateY(0);
  }

  .nav-links a {
    padding: 14px 2px;
    border-bottom: 1px solid var(--line);
    font-size: 0.96rem;
    color: var(--ink);
  }

  .nav-links a:last-child {
    border-bottom: 0;
  }

  .nav-links a::after {
    display: none;
  }

  .nav-actions .button--ghost {
    display: none;
  }

  .menu-toggle {
    display: block;
  }

  .hero {
    padding-top: calc(var(--header-height) + 56px);
  }

  .hero-grid {
    grid-template-columns: 1fr;
    gap: 54px;
  }

  .hero-copy {
    text-align: center;
  }

  .hero-lead {
    margin-inline: auto;
  }

  .hero-actions,
  .platform-pills {
    justify-content: center;
  }

  .hero-foot {
    flex-direction: column;
    text-align: center;
  }

  .hero-foot-items {
    justify-content: center;
  }

  .feature-grid,
  .download-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .download-card--soon {
    grid-column: 1 / -1;
  }

  .how-grid,
  .faq-grid {
    grid-template-columns: 1fr;
    gap: 44px;
  }

  .faq-intro {
    max-width: 560px;
  }

  .contact-card {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .footer-main {
    grid-template-columns: 1fr;
    gap: 42px;
  }
}

/* 中等屏：两侧留白从 48px 收到 40px，避免内容过度贴边 */
@media (max-width: 1280px) {
  .container {
    width: min(100% - 80px, var(--container));
  }
}

@media (max-width: 680px) {
  .container {
    width: min(100% - 32px, var(--container));
  }

  .section {
    padding: 84px 0;
  }

  .nav-actions .button--primary {
    display: none;
  }

  .hero h1 {
    font-size: clamp(2.2rem, 10vw, 3rem);
  }

  .hero-lead {
    font-size: 0.98rem;
  }

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

  .hero-actions .button {
    width: 100%;
  }

  .floating-card {
    display: none;
  }

  .device-content {
    padding: 24px 18px 20px;
  }

  .mock-stats {
    padding: 14px 10px;
    gap: 6px;
  }

  .mock-stats strong {
    font-size: 0.9rem;
  }

  .mock-chart {
    padding: 14px 12px 8px;
  }

  .hero-foot-items {
    gap: 14px 22px;
  }

  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 30px 16px;
  }

  .feature-grid,
  .download-grid {
    grid-template-columns: 1fr;
  }

  .download-card--soon {
    grid-column: auto;
  }

  .download-card {
    padding: 28px 24px;
  }

  .steps li {
    padding: 22px 20px;
    gap: 16px;
  }

  .faq-item summary {
    padding: 18px 20px;
    font-size: 0.96rem;
  }

  .faq-answer {
    padding: 0 20px 20px;
  }

  .contact-card {
    padding: 42px 24px;
    border-radius: var(--radius-md);
  }

  .footer-links {
    grid-template-columns: repeat(2, 1fr);
    gap: 28px 20px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .telegram-fab {
    right: 16px;
    bottom: 16px;
    width: 50px;
    height: 50px;
  }
}