:root {
  --bg: #ffffff;
  --text: #171717;
  --muted: #666;
  --line: #ececec;
  --btn: #111;
  --btn-hover: #2a2a2a;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

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

.container {
  width: min(960px, 92vw);
  margin: 0 auto;
}

.site-header {
  border-bottom: 1px solid var(--line);
}

.header-inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-size: 1.2rem;
  font-weight: 700;
}

.top-nav,
.footer-nav {
  display: flex;
  gap: 1.2rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.top-nav a:hover,
.footer-nav a:hover,
.top-nav a.active {
  color: var(--text);
}

.hero {
  min-height: calc(100vh - 140px);
  display: grid;
  place-items: center;
}

.hero-inner {
  text-align: center;
  padding: 4rem 0;
}

.hero h1 {
  margin: 0;
  font-size: clamp(2.5rem, 8vw, 5rem);
  letter-spacing: 0.02em;
}

.tagline {
  margin: 1rem 0 2rem;
  color: var(--muted);
  font-size: 1.05rem;
}

.cta-group {
  display: flex;
  gap: 0.8rem;
  justify-content: center;
  flex-wrap: wrap;
}

.store-btn {
  background: var(--btn);
  color: #fff;
  border-radius: 999px;
  padding: 0.65rem 1.1rem;
  font-size: 0.95rem;
  transition: background 0.2s ease;
}

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

.doc-page {
  padding: 3rem 0 4rem;
}

.doc-page h1 {
  margin: 0;
  font-size: clamp(1.8rem, 5vw, 2.6rem);
}

.doc-page section {
  margin-top: 1.5rem;
}

.doc-page h2 {
  margin-bottom: 0.5rem;
  font-size: 1.1rem;
}

.doc-page p {
  margin: 0;
  color: #303030;
}

.muted {
  color: var(--muted);
  margin-top: 0.4rem;
}

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

.footer-inner {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  color: var(--muted);
  font-size: 0.9rem;
}