/* 全站基础：重置、变量、排版、按钮、导航、页脚、栅格 */
:root {
  --color-bg: #ffffff;
  --color-bg-soft: #f9fafb;
  --color-text: #1f2937;
  --color-text-light: #6b7280;
  --color-primary: #10b981;
  --color-primary-hover: #059669;
  --color-accent: #0ea5e9;
  --color-border: #e5e7eb;
  --color-hero-end: #f0fdf4;
  --color-badge: #ecfdf5;
  --color-footer: #1f2937;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.1);
  --container: 1180px;
  --header-h: 64px;
}

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Noto Sans SC", "Source Han Sans SC", system-ui, -apple-system, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s, background 0.2s, border-color 0.2s, transform 0.2s;
}

a:hover {
  color: var(--color-primary-hover);
}

:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* 跳过导航 */
.skip-link {
  position: absolute;
  left: 12px;
  top: -48px;
  z-index: 200;
  background: var(--color-primary);
  color: #fff;
  padding: 8px 14px;
  border-radius: 8px;
  font-weight: 600;
}

.skip-link:focus {
  top: 12px;
  color: #fff;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  font-family: inherit;
  line-height: 1.2;
}

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

.btn-primary:hover {
  background: var(--color-primary-hover);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(16, 185, 129, 0.3);
}

.btn-secondary {
  background: #fff;
  color: var(--color-text);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* 页头 */
.site-header {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 700;
  color: var(--color-text);
  flex-shrink: 0;
}

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

.logo img {
  width: 32px;
  height: 32px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.site-nav a {
  color: var(--color-text);
  font-size: 14px;
  font-weight: 500;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--color-primary);
}

.nav-cta {
  background: var(--color-primary);
  color: #fff;
  padding: 9px 20px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
}

.nav-cta:hover {
  background: var(--color-primary-hover);
  color: #fff;
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  padding: 8px 10px;
  color: var(--color-text);
}

.nav-toggle-bars,
.nav-toggle-bars::before,
.nav-toggle-bars::after {
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  position: relative;
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
}

.nav-toggle-bars::before { top: -6px; }
.nav-toggle-bars::after { top: 6px; }

/* 页脚 */
.site-footer {
  background: var(--color-footer);
  color: rgba(255, 255, 255, 0.6);
  padding: 56px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 36px;
}

.footer-brand .logo {
  color: #fff;
  margin-bottom: 14px;
}

.footer-brand .logo:hover {
  color: #fff;
}

.brand-desc {
  font-size: 13px;
  line-height: 1.7;
}

.brand-features {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-top: 14px;
  font-size: 12px;
  list-style: none;
}

.brand-stats {
  display: flex;
  gap: 18px;
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  flex-wrap: wrap;
  font-size: 12px;
}

.brand-stats strong {
  color: var(--color-primary);
  font-size: 15px;
  font-weight: 700;
}

.footer-col h2 {
  color: #fff;
  font-size: 14px;
  margin-bottom: 14px;
  font-weight: 600;
}

.footer-col a {
  display: block;
  color: rgba(255, 255, 255, 0.6);
  padding: 5px 0;
  font-size: 13px;
}

.footer-col a:hover {
  color: var(--color-primary);
}

.footer-meta {
  margin-top: 16px;
  font-size: 13px;
  line-height: 1.8;
}

.footer-meta a {
  color: rgba(255, 255, 255, 0.75);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 20px;
  text-align: center;
  font-size: 12px;
}

.footer-bottom p {
  margin: 4px 0;
}

.footer-bottom a {
  color: rgba(255, 255, 255, 0.6);
}

/* 栅格与区块 */
.section {
  padding: 80px 0;
}

.section-soft {
  background: var(--color-bg-soft);
}

.eyebrow {
  display: block;
  color: var(--color-primary);
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 12px;
}

.section-title {
  font-size: 36px;
  font-weight: 800;
  margin-bottom: 16px;
  line-height: 1.2;
}

.section-sub {
  font-size: 16px;
  color: var(--color-text-light);
  max-width: 680px;
  line-height: 1.7;
}

.section-head {
  text-align: center;
  margin-bottom: 56px;
}

.section-head .section-sub {
  margin: 0 auto;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

/* 面包屑 */
.breadcrumb {
  padding: 16px 0 0;
  font-size: 13px;
  color: var(--color-text-light);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
}

.breadcrumb li:not(:last-child)::after {
  content: "/";
  margin-left: 8px;
  color: var(--color-border);
}

.breadcrumb a {
  color: var(--color-text-light);
}

.breadcrumb [aria-current="page"] {
  color: var(--color-text);
}

/* 返回顶部 */
.back-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 44px;
  height: 44px;
  border: none;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-size: 20px;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
  z-index: 80;
}

.back-top.is-visible {
  opacity: 1;
  pointer-events: auto;
}

.back-top:hover {
  background: var(--color-primary-hover);
  transform: translateY(-2px);
}

/* 表单提示 */
.form-error {
  color: #b45309;
  font-size: 13px;
  margin-top: 6px;
}

.form-success {
  background: var(--color-badge);
  color: var(--color-primary-hover);
  padding: 12px 14px;
  border-radius: 8px;
  margin-bottom: 16px;
  font-size: 14px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

@media (max-width: 1023px) {
  .nav-toggle { display: inline-flex; align-items: center; }
  .site-nav {
    display: none;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px 0 20px;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow);
  }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: 12px 24px; }
  .header-inner .nav-cta { display: none; }
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .section-title { font-size: 28px; }
  .section { padding: 60px 0; }
}

@media (max-width: 767px) {
  .grid-3 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .section-title { font-size: 26px; }
}