:root {
  --bg-dark: #090d16;
  --bg-card: #111827;
  --bg-card-hover: #162033;
  --border-color: #212e44;
  --border-glow: #2f81f7;
  --text-main: #f0f6fc;
  --text-muted: #8b949e;
  --accent-green: #3fb950;
  --accent-blue: #2f81f7;
  --accent-cyan: #39c5bb;
  --accent-orange: #f0883e;
  --radius-lg: 16px;
  --radius-md: 10px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background-color: var(--bg-dark);
  color: var(--text-main);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
}

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 导航条 */
nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 0;
  border-bottom: 1px solid var(--border-color);
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  text-decoration: none;
}
.brand .logo-badge {
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-green));
  width: 32px;
  height: 32px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
}
.nav-links {
  display: flex;
  gap: 20px;
  align-items: center;
}
.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
}
.nav-links a:hover { color: #fff; }
.btn-nav {
  padding: 8px 16px;
  background: #21262d;
  color: #fff !important;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  transition: all 0.2s;
}
.btn-nav:hover {
  background: var(--accent-blue);
  border-color: var(--accent-blue);
}

/* Hero 首屏 */
.hero {
  padding: 80px 0 60px;
  text-align: center;
  position: relative;
}
.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 30px;
  background: rgba(63, 185, 80, 0.12);
  border: 1px solid rgba(63, 185, 80, 0.35);
  color: var(--accent-green);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 24px;
}
.hero h1 {
  font-size: 48px;
  font-weight: 800;
  letter-spacing: -1px;
  margin-bottom: 18px;
  background: linear-gradient(135deg, #ffffff 40%, #79c0ff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero p {
  font-size: 18px;
  color: var(--text-muted);
  max-width: 720px;
  margin: 0 auto 36px;
}
.hero-btns {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}
.btn-pri {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  background: linear-gradient(135deg, #238636, #2ea043);
  color: #fff;
  border-radius: 10px;
  text-decoration: none;
  font-size: 15px;
  font-weight: 600;
  box-shadow: 0 4px 14px rgba(35, 134, 54, 0.4);
  transition: transform 0.15s, box-shadow 0.15s;
}
.btn-pri:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(35, 134, 54, 0.6); }
.btn-sec {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  background: #1c2430;
  border: 1px solid var(--border-color);
  color: #fff;
  border-radius: 10px;
  text-decoration: none;
  font-size: 15px;
  font-weight: 600;
  transition: all 0.2s;
}
.btn-sec:hover { background: #263140; border-color: var(--border-glow); }

/* 特性网格 */
.section-title {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  margin: 70px 0 16px;
}
.section-sub {
  text-align: center;
  color: var(--text-muted);
  margin-bottom: 40px;
  font-size: 15px;
}
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
}
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: transform 0.2s, border-color 0.2s;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--border-glow);
  background: var(--bg-card-hover);
}
.card-icon {
  font-size: 32px;
  margin-bottom: 16px;
}
.card h3 {
  font-size: 18px;
  margin-bottom: 10px;
  color: #fff;
}
.card p {
  color: var(--text-muted);
  font-size: 14px;
}

/* 接线图卡片 */
.pinout-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 30px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 30px;
  align-items: center;
}
@media (max-width: 768px) {
  .pinout-box { grid-template-columns: 1fr; }
  .hero h1 { font-size: 34px; }
}
.pin-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
.pin-table th, .pin-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border-color);
  text-align: left;
}
.pin-table th { color: var(--text-muted); font-weight: 600; }
.pin-table code {
  background: #090d16;
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent-cyan);
  font-family: monospace;
}

/* 固件发布专区 */
.firmware-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.fw-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}
.fw-item.recommended {
  border-color: rgba(63, 185, 80, 0.6);
  background: rgba(63, 185, 80, 0.04);
}
.fw-info h4 {
  font-size: 17px;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 10px;
}
.badge-rec {
  background: rgba(63, 185, 80, 0.2);
  color: var(--accent-green);
  border: 1px solid rgba(63, 185, 80, 0.5);
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 12px;
}
.fw-meta {
  color: var(--text-muted);
  font-size: 13px;
  margin-top: 6px;
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.fw-desc {
  font-size: 13px;
  color: #c9d1d9;
  margin-top: 8px;
  line-height: 1.5;
}
.fw-action a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  background: var(--accent-blue);
  color: #fff;
  border-radius: 8px;
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
  transition: background 0.2s;
}
.fw-action a:hover { background: #388bfd; }

/* 页脚 */
footer {
  border-top: 1px solid var(--border-color);
  margin-top: 80px;
  padding: 40px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}
footer a { color: var(--text-muted); text-decoration: none; }
footer a:hover { color: #fff; }