/* ========== 基础重置与变量 ========== */
:root {
  --color-bg: #fafaf9;
  --color-surface: #ffffff;
  --color-text: #1c1917;
  --color-text-secondary: #57534e;
  --color-text-muted: #a8a29e;
  --color-primary: #1c1917;
  --color-primary-hover: #292524;
  --color-border: #e7e5e4;
  --color-accent: #0f766e;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, sans-serif;
  --radius: 12px;
  --radius-lg: 20px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.06);
  --transition: 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
}

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

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

img {
  max-width: 100%;
  display: block;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ========== 按钮 ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 15px;
  font-weight: 500;
  padding: 10px 20px;
  border-radius: 999px;
  border: 1.5px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  transform: translateY(-1px);
}

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

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

.btn-sm {
  padding: 8px 16px;
  font-size: 14px;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 16px;
}

/* ========== 导航 ========== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 250, 249, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s;
}

.header.scrolled {
  border-bottom-color: var(--color-border);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 18px;
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  color: #fff;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 700;
}

.nav {
  display: flex;
  gap: 32px;
}

.nav a {
  font-size: 15px;
  color: var(--color-text-secondary);
  transition: color var(--transition);
}

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

/* ========== Hero ========== */
.hero {
  padding: 100px 0 120px;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  font-size: 13px;
  color: var(--color-text-muted);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 28px;
}

.hero-title {
  font-size: clamp(2.8rem, 6vw, 4.2rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
  color: var(--color-text);
}

.hero-title em {
  font-style: normal;
  color: var(--color-accent);
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--color-text-secondary);
  max-width: 520px;
  margin: 0 auto 40px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ========== 通用 Section ========== */
.section {
  padding: 100px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-header h2 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-header p {
  font-size: 1.05rem;
  color: var(--color-text-secondary);
}

/* ========== 功能卡片 ========== */
.features {
  background: var(--color-surface);
}

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

.feature-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  transition: all var(--transition);
}

.feature-card:hover {
  border-color: #d6d3d1;
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 18px;
}

.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.feature-card p {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  line-height: 1.65;
}

/* ========== 亮点列表 ========== */
.highlight-list {
  display: flex;
  flex-direction: column;
  gap: 40px;
  max-width: 720px;
  margin: 0 auto;
}

.highlight-item {
  display: flex;
  gap: 28px;
  align-items: flex-start;
}

.highlight-number {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-muted);
  min-width: 48px;
  line-height: 1.2;
}

.highlight-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.highlight-content p {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ========== 下载区域 ========== */
.download {
  background: var(--color-surface);
}

.download-card {
  max-width: 560px;
  margin: 0 auto;
  text-align: center;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
  box-shadow: var(--shadow-lg);
}

.download-version {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  margin-bottom: 28px;
}

.download-version strong {
  color: var(--color-text);
  font-weight: 600;
}

.download-buttons {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.download-note {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 24px;
  line-height: 1.6;
}

.download-links {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}

.download-links a {
  color: var(--color-accent);
  transition: opacity var(--transition);
}

.download-links a:hover {
  opacity: 0.8;
}

/* ========== 页脚 ========== */
.footer {
  padding: 48px 0;
  border-top: 1px solid var(--color-border);
}

.footer-inner {
  text-align: center;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  margin-bottom: 12px;
}

.footer-brand .logo-icon {
  width: 28px;
  height: 28px;
  font-size: 14px;
}

.footer-text {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
}

.footer-text a {
  color: var(--color-accent);
}

.footer-sub {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
  .nav {
    display: none;
  }

  .hero {
    padding: 70px 0 90px;
  }

  .hero-title {
    font-size: 2.4rem;
  }

  .section {
    padding: 70px 0;
  }

  .highlight-item {
    flex-direction: column;
    gap: 8px;
  }

  .download-card {
    padding: 36px 24px;
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .btn-lg {
    width: 100%;
  }
}