:root {
  color-scheme: dark;

  /* 背景：更纯净的深色，不再带紫灰色调 */
  --bg-base: #05070a;
  --bg-panel: #0f141d;
  --bg-hover: #171e29;

  /* 边框：带一点点蓝色的深灰 */
  --border: #222b3a;
  --border-hover: #313e54;

  /* 文字：高亮度白 + 现代蓝灰 */
  --text-main: #ffffff;
  --text-soft: #8a99ad;
  --text-muted: #4e5d72;

  /* 核心品牌色：电光蓝 */
  --primary: #0070f3;
  --primary-hover: #0081ff;
  --primary-invert: #ffffff;

  /* 辅助 / 强调色：极光青 */
  --accent: #00dfd8;

  /* 状态色 */
  --success: #00e676;
  --warning: #f5a623;
  --danger: #ff4d4d;

  --radius-lg: 10px;
  --radius-md: 8px;
  --radius-sm: 4px;

  --content-width: 1040px;
  --font-sans: "Inter", -apple-system, system-ui, sans-serif;
}

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

body {
  background-color: var(--bg-base);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s;
}

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

button,
input,
select {
  font: inherit;
}

.page-shell {
  width: min(calc(100% - 48px), var(--content-width));
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-header {
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 600;
  font-size: 1.125rem;
}

.brand-logo {
  width: 24px;
  height: 24px;
  background: var(--text-main);
  color: var(--bg-base);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 800;
}

.site-nav {
  display: flex;
  gap: 24px;
  align-items: center;
  font-size: 0.875rem;
  color: var(--text-soft);
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 36px;
  padding: 0 16px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.btn-primary {
  background: var(--primary);
  color: var(--primary-invert);
  box-shadow: 0 4px 14px 0 rgba(0, 112, 243, 0.3);
}

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

.btn-outline {
  background: transparent;
  border-color: var(--border);
  color: var(--text-main);
}

.btn-outline:hover {
  background: var(--bg-hover);
  border-color: var(--border-hover);
}

.panel {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.panel-header {
  padding: 24px;
  border-bottom: 1px solid var(--border);
}

.panel-header h2,
.panel-header h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.panel-header p {
  color: var(--text-soft);
  font-size: 0.875rem;
  line-height: 1.5;
}

.panel-body {
  padding: 24px;
}

.desc-list {
  display: flex;
  flex-direction: column;
}

.desc-row {
  display: flex;
  justify-content: space-between;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.desc-row:last-child {
  border-bottom: none;
}

.desc-term {
  color: var(--text-main);
  font-size: 0.875rem;
  font-weight: 500;
}

.desc-detail {
  color: var(--text-soft);
  font-size: 0.875rem;
  text-align: right;
}

.hero {
  padding: 120px 0 80px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 24px;
}

.hero p.lead {
  color: var(--text-soft);
  font-size: 1.125rem;
  max-width: 720px;
  margin: 0 auto 40px;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
}

.hero-actions .btn {
  height: 44px;
  padding: 0 24px;
  font-size: 1rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
  margin: 80px 0;
}

.feature-card {
  padding: 32px;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  text-align: left;
}

.feature-card h3 {
  font-size: 1.125rem;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-soft);
  font-size: 0.9375rem;
}

.text-gradient {
  background: linear-gradient(135deg, #ffffff 0%, var(--primary) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.site-footer {
  margin-top: auto;
  padding: 40px 0;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-soft);
  font-size: 0.875rem;
}

.footer-links {
  display: flex;
  gap: 24px;
}

@media (max-width: 768px) {
  .site-nav {
    display: none;
  }

  .grid-3 {
    grid-template-columns: 1fr;
  }

  .site-footer {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }
}