/* 设计基线：颜色、排版、卡片等 */
:root {
  --pri: #6c6cf7;
  --acc: #1ad66c;
  --pch: #ff86d0;
  --sky: #8fd8ff;
  --ink: #150a3c;
  --mut: #5c5f72;
  --card: #fff;
  --line: #e8eaf2;
  --radius: 18px;
  --radius-lg: 22px;
  --shadow: 0 10px 30px rgba(17, 17, 26, 0.08);
}

/* 柔和渐变背景与基础排版 */
body {
  margin: 0;
  color: var(--ink);
  font:
    16px/1.6 system-ui,
    -apple-system,
    "PingFang SC",
    "SF Pro",
    Segoe UI,
    Roboto,
    Arial;
  position: relative;
  min-height: 100dvh; /* 让画布充满视口高度 */
  background: #fafaff; /* 背景基色，防止闪烁 */
}

/* 使用伪元素绘制柔光背景 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(
      1200px 600px at 10% -10%,
      rgba(108, 108, 247, 0.2),
      transparent 60%
    ),
    radial-gradient(
      900px 500px at 90% 0%,
      rgba(255, 134, 208, 0.18),
      transparent 55%
    ),
    radial-gradient(
      800px 400px at 50% 110%,
      rgba(26, 214, 108, 0.14),
      transparent 60%
    ),
    #fafaff;
  background-repeat: no-repeat; /* 避免出现横条带 */
}

/* 容器与栅格 */
.wrap {
  max-width: 1080px;
  padding: 40px 20px;
  margin: 0 auto;
}
.grid {
  display: grid;
  gap: 20px;
}
.grid.cols-4 {
  grid-template-columns: repeat(4, 1fr);
}
@media (max-width: 960px) {
  .grid.cols-4 {
    grid-template-columns: 1fr 1fr;
  }
}
@media (max-width: 600px) {
  .grid.cols-4 {
    grid-template-columns: 1fr;
  }
}

/* 顶部导航 */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 0;
  backdrop-filter: saturate(120%) blur(6px);
}
.brand {
  font-weight: 800;
  letter-spacing: 0.5px;
}
.lang a {
  padding: 6px 10px;
  border-radius: 999px;
  text-decoration: none;
  color: var(--ink);
}
.lang a.active {
  background: rgba(108, 108, 247, 0.12);
  color: #222;
}

/* 英雄区 */
.hero {
  padding: 72px 0 36px;
  text-align: center;
}
.kicker {
  color: var(--pri);
  font-weight: 700;
  letter-spacing: 0.6px;
  text-transform: uppercase;
  font-size: 12px;
}
h1 {
  font-size: 42px;
  line-height: 1.15;
  margin: 0.3em 0;
}
.lead {
  max-width: 680px;
  margin: 0 auto 24px;
  color: var(--mut);
}
.cta {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  border: 0;
  border-radius: 999px;
  padding: 12px 18px;
  font-weight: 700;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition:
    transform 0.2s,
    box-shadow 0.2s;
}
.btn-primary {
  background: var(--pri);
  color: #fff;
}
.btn-ghost {
  background: #fff;
  color: var(--pri);
  outline: 1px solid rgba(108, 108, 247, 0.25);
}
.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 40px rgba(17, 17, 26, 0.12);
}

/* 功能卡片 */
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease,
    opacity 0.4s ease;
  opacity: 0;
  transform: translateY(8px);
}
.card.is-in {
  opacity: 1;
  transform: none;
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 44px rgba(17, 17, 26, 0.12);
}
.card .icon {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: linear-gradient(
    135deg,
    rgba(108, 108, 247, 0.18),
    rgba(255, 134, 208, 0.18)
  );
  margin-bottom: 12px;
  font-size: 22px;
}
.card h3 {
  margin: 6px 0 8px;
  font-size: 18px;
}
.card p {
  color: var(--mut);
  margin: 0;
}

/* CTA 横幅 */
.banner {
  margin: 64px 0 24px;
  padding: 24px;
  border-radius: var(--radius-lg);
  background: linear-gradient(
    135deg,
    rgba(108, 108, 247, 0.14),
    rgba(26, 214, 108, 0.12)
  );
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

/* 页脚 */
.footer {
  color: #7a8199;
  border-top: 1px solid var(--line);
  padding: 28px 0;
  font-size: 14px;
}

/* 暗色模式 */
@media (prefers-color-scheme: dark) {
  body {
    background: #0f1020; /* 暗色基色 */
  }
  body::before {
    background: #0f1020; /* 暗色模式下不使用渐变 */
    background-repeat: no-repeat;
  }
  .card {
    background: #181a2a;
    border-color: #2a2e44;
  }
  .lead,
  .footer,
  .card p {
    color: #b9bed1;
  }
  .btn-ghost {
    background: #181a2a;
    color: var(--sky);
    outline: 1px solid #2a2e44;
  }
}