:root {
  --bg: #f5f5f7;
  --text: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-tertiary: #86868b;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --border: #d2d2d7;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body { height: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display",
    "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.nav {
  position: sticky;
  top: 0;
  background: rgba(245, 245, 247, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.nav-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 22px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand { display: flex; align-items: center; gap: 9px; }

.brand-mark {
  width: 28px;
  height: 28px;
  border-radius: 7px;
  background: linear-gradient(180deg, #4aa8ff, #0066d9);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.brand-name { font-size: 16px; font-weight: 600; }

.hero {
  flex: 1;
  max-width: 720px;
  margin: 0 auto;
  padding: 96px 24px 64px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.logo { margin-bottom: 24px; }

.avatar {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: linear-gradient(180deg, #4aa8ff, #0066d9);
  color: #fff;
  font-size: 30px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
}

h1 {
  font-size: 40px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.sub { font-size: 17px; color: var(--text-secondary); line-height: 1.5; margin-bottom: 8px; }
.sub-muted { font-size: 14px; color: var(--text-tertiary); line-height: 1.6; margin-bottom: 32px; }

code {
  background: #e8e8ed;
  border-radius: 5px;
  padding: 1px 6px;
  font-size: 0.9em;
}

.btn {
  display: inline-block;
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  border-radius: 12px;
  padding: 10px 22px;
  transition: background 0.18s ease, transform 0.05s ease;
  cursor: pointer;
  border: none;
}

.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-hover); }
.btn-ghost { background: transparent; color: var(--accent); }
.btn-ghost:hover { background: rgba(0, 113, 227, 0.08); }
.btn-lg { font-size: 17px; padding: 14px 34px; margin-top: 8px; }

.foot {
  text-align: center;
  font-size: 12px;
  color: var(--text-tertiary);
  padding: 28px 0 32px;
  border-top: 1px solid rgba(0, 0, 0, 0.05);
}