:root {
  --bg: #f5f7fb;
  --text: #111827;
  --muted: #617083;
  --line: #dce3ec;
  --card: #ffffff;
  --green: #16a37d;
  --green-dark: #0f7b61;
  --blue: #2563eb;
  --shadow: 0 18px 50px rgba(17, 24, 39, 0.1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  background: var(--bg);
  font-family: "Inter", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.65;
}

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

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

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 68px;
  padding: 0 6vw;
  background: rgba(245, 247, 251, 0.9);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
}

.brand span {
  display: grid;
  width: 36px;
  height: 36px;
  place-items: center;
  color: #fff;
  background: var(--text);
  border-radius: 8px;
  font-size: 14px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 24px;
  color: var(--muted);
  font-size: 15px;
}

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

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 360px;
  gap: 36px;
  align-items: center;
  min-height: calc(100vh - 68px);
  padding: 70px 6vw 52px;
}

.hero-copy {
  max-width: 760px;
}

.tag {
  margin: 0 0 14px;
  color: var(--green-dark);
  font-size: 14px;
  font-weight: 800;
}

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

h1 {
  margin-bottom: 20px;
  font-size: clamp(38px, 7vw, 76px);
  line-height: 1.05;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 16px;
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.15;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 8px;
  font-size: 20px;
}

.lead {
  max-width: 680px;
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 18px;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 22px;
}

.btn,
.copy-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 12px 20px;
  border: 1px solid transparent;
  border-radius: 8px;
  font-weight: 800;
  cursor: pointer;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.btn:hover,
.copy-btn:hover {
  transform: translateY(-2px);
}

.btn.primary,
.copy-btn {
  color: #fff;
  background: var(--green);
  box-shadow: 0 12px 26px rgba(22, 163, 125, 0.22);
}

.btn.light {
  color: var(--text);
  background: #fff;
  border-color: var(--line);
}

.quick-points {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.quick-points span {
  padding: 8px 12px;
  color: #1e3a31;
  background: #e8f7f2;
  border: 1px solid #c8ece1;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 700;
}

.contact-card {
  padding: 22px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.contact-card img {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.contact-card p {
  margin: 16px 0 14px;
  color: var(--muted);
  text-align: center;
}

.copy-btn {
  width: 100%;
  font-family: inherit;
  font-size: 15px;
}

.section {
  padding: 74px 6vw;
}

.section-title {
  max-width: 720px;
  margin-bottom: 28px;
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.cards article,
.plan-list div,
.notice {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 10px 28px rgba(17, 24, 39, 0.06);
}

.cards article {
  min-height: 190px;
  padding: 24px;
}

.cards span {
  display: inline-block;
  margin-bottom: 24px;
  color: var(--blue);
  font-size: 28px;
  font-weight: 900;
}

.cards p,
.plan-list p,
.notice p {
  color: var(--muted);
}

.tutorial {
  padding-top: 32px;
}

.video-box {
  overflow: hidden;
  max-width: 920px;
  background: #000;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.video-box video {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
}

.compact {
  display: grid;
  grid-template-columns: 0.72fr 1.28fr;
  gap: 28px;
  align-items: start;
  background: #fff;
}

.plan-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.plan-list div {
  padding: 24px;
}

.plan-list strong {
  display: block;
  margin-bottom: 10px;
  font-size: 22px;
}

.plan-list p {
  margin-bottom: 0;
}

.notice {
  margin: 58px 6vw;
  padding: 18px 20px;
}

.notice p {
  margin: 0;
  font-size: 14px;
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 24px 6vw;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

@media (max-width: 900px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
    padding-top: 14px;
    padding-bottom: 14px;
  }

  .nav {
    width: 100%;
    justify-content: space-between;
    gap: 10px;
  }

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

  .hero {
    min-height: auto;
    padding-top: 52px;
  }

  .contact-card {
    max-width: 420px;
    margin: 0 auto;
  }

  .cards,
  .plan-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .topbar,
  .hero,
  .section,
  .compact,
  .footer {
    padding-left: 18px;
    padding-right: 18px;
  }

  .nav {
    font-size: 14px;
  }

  h1 {
    font-size: 38px;
  }

  .lead {
    font-size: 16px;
  }

  .actions,
  .btn {
    width: 100%;
  }

  .notice {
    margin-left: 18px;
    margin-right: 18px;
  }

  .footer {
    flex-direction: column;
  }
}