/* ---- 基础 ---- */

:root {
  --bg: #ffffff;
  --bg-alt: #f5f5f7;
  --nav-bg: rgba(251, 251, 253, 0.8);
  --text: #1d1d1f;
  --text-2: #6e6e73;
  --line: #d2d2d7;
  --blue: #0071e3;
  --blue-hover: #0077ed;
  --link: #06c;
  --radius: 18px;
  --wrap: 1020px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei",
    "Helvetica Neue", Helvetica, Arial, sans-serif;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 60px;
  -webkit-user-select: none;
  user-select: none;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.47;
  letter-spacing: -0.022em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.08;
  letter-spacing: -0.015em;
}

p {
  margin: 0;
}

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

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

img {
  display: block;
  max-width: 100%;
  -webkit-user-drag: none;
  -khtml-user-drag: none;
  -moz-user-drag: none;
  -o-user-drag: none;
  user-drag: none;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: 24px;
}

/* ---- 按钮与链接 ---- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 980px;
  font-size: 17px;
  font-weight: 400;
  white-space: nowrap;
  transition: background 0.2s ease, color 0.2s ease;
}

.btn--primary {
  padding: 12px 28px;
  background: var(--blue);
  color: #fff;
}

.btn--primary:hover {
  background: var(--blue-hover);
}

.link {
  color: var(--link);
  font-size: 17px;
}

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

/* ---- 顶栏 ---- */

.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}

.nav__inner {
  display: flex;
  align-items: center;
  gap: 32px;
  max-width: var(--wrap);
  height: 52px;
  margin-inline: auto;
  padding-inline: 24px;
}

.nav__brand {
  display: flex;
  align-items: center;
  margin-right: auto;
}

.nav__brand img {
  height: 22px;
  width: auto;
}

.nav__links {
  display: flex;
  gap: 28px;
  font-size: 14px;
  color: var(--text);
}

.nav__links a {
  opacity: 0.8;
  transition: opacity 0.2s ease;
}

.nav__links a:hover {
  opacity: 1;
}

.nav__cta {
  padding: 6px 16px;
  border-radius: 980px;
  background: var(--blue);
  color: #fff;
  font-size: 14px;
  transition: background 0.2s ease;
}

.nav__cta:hover {
  background: var(--blue-hover);
}

/* ---- 首屏 ---- */

.hero {
  padding: 90px 0 40px;
  text-align: center;
}

.hero__title {
  font-size: clamp(38px, 6.4vw, 72px);
  font-weight: 700;
}

.hero__lead {
  margin-top: 22px;
  font-size: clamp(19px, 2vw, 24px);
  line-height: 1.4;
  color: var(--text-2);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 10px 30px;
  margin-top: 34px;
}

.hero__meta {
  margin-top: 20px;
  color: var(--text-2);
  font-size: 14px;
}

.hero__shot {
  max-width: 1200px;
  margin: 60px auto 0;
  padding-inline: 24px;
}

.hero__shot img {
  width: 100%;
  height: auto;
  border: 1px solid rgba(0, 0, 0, 0.09);
  border-radius: 14px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05), 0 30px 60px -24px rgba(0, 0, 0, 0.22);
}

/* ---- 段落 ---- */

.section {
  padding: 96px 0;
}

.section--alt {
  background: var(--bg-alt);
}

.section__title {
  font-size: clamp(30px, 4.4vw, 52px);
  font-weight: 700;
  text-align: center;
}

.section__title--sub {
  margin-top: 104px;
}

.section__lead {
  max-width: 620px;
  margin: 18px auto 0;
  color: var(--text-2);
  font-size: clamp(17px, 1.7vw, 21px);
  line-height: 1.45;
  text-align: center;
}

/* ---- 功能瓦片 ---- */

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 60px;
}

.tile {
  padding: 34px 30px;
  border-radius: var(--radius);
  background: #fff;
}

.tile__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border-radius: 12px;
  background: linear-gradient(180deg, #e8f2ff, #f4f9ff);
  color: var(--blue);
}

.tile__icon svg {
  width: 24px;
  height: 24px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.tile h3 {
  margin-top: 22px;
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.tile p {
  margin-top: 10px;
  color: var(--text-2);
  font-size: 15px;
  line-height: 1.5;
}

/* ---- 细节 ---- */

.notes {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 36px 60px;
  max-width: 860px;
  margin: 48px auto 0;
}

.notes h3 {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.notes p {
  margin-top: 8px;
  color: var(--text-2);
  font-size: 15px;
  line-height: 1.5;
}

/* ---- 下载 ---- */

.cta {
  text-align: center;
}

.cta__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.cta__icon {
  width: 80px;
  height: 80px;
  margin-bottom: 28px;
}

.cta .btn {
  margin-top: 34px;
}

.cta__meta {
  margin-top: 20px;
  color: var(--text-2);
  font-size: 14px;
}

/* ---- 页脚 ---- */

.footer {
  padding: 40px 0 48px;
  background: var(--bg-alt);
  border-top: 1px solid var(--line);
  color: var(--text-2);
  font-size: 12px;
  line-height: 1.6;
}

.footer__links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin-bottom: 14px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.footer__legal a:hover {
  text-decoration: underline;
}

.footer__links a {
  font-size: 13px;
  color: var(--text);
}

.footer__links a:hover {
  text-decoration: underline;
}

/* ---- 入场 ---- */

.reveal {
  transition: opacity 0.6s ease, transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal--pending {
  opacity: 0;
  transform: translateY(16px);
}

/* ---- 窄屏 ---- */

@media (max-width: 960px) {
  .grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .nav__links {
    display: none;
  }
}

@media (max-width: 640px) {
  .wrap,
  .nav__inner {
    padding-inline: 20px;
  }

  .hero {
    padding: 56px 0 24px;
  }

  .section {
    padding: 64px 0;
  }

  .hero__shot {
    margin-top: 40px;
  }

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

  .section__title--sub {
    margin-top: 64px;
  }
}

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

  .reveal,
  .reveal--pending {
    opacity: 1;
    transform: none;
    transition: none;
  }
}