/* ============================================================
   妥账 - 智能进销存管理 官网样式
   基于 设计稿 (visual design) 提取，保持视觉一致
   ============================================================ */

/* ── Design Tokens ── */
:root {
  /* Brand Color System */
  --color-primary: #1B9AA4;
  --color-primary-hover: #168A93;
  --color-primary-active: #117A82;
  --color-primary-light: #E6F5F6;
  --color-primary-lighter: #F0FAFB;
  --color-primary-bg: #F7FDFD;
  --color-primary-text: #0D4F53;
  --color-primary-50: #E6F5F6;
  --color-primary-100: #CCECED;
  --color-primary-200: #99D9DD;
  --color-primary-300: #66C7CE;
  --color-primary-400: #33B5BE;
  --color-primary-500: #1B9AA4;
  --color-primary-600: #168A93;
  --color-primary-700: #117A82;
  --color-primary-800: #0C6A71;
  --color-primary-900: #075A60;

  /* Neutral System */
  --color-bg: #F5F7FA;
  --color-bg-elevated: #FFFFFF;
  --color-bg-inset: #EBEEF3;
  --color-bg-hover: #F0F2F5;
  --color-bg-active: #E8EBF0;
  --color-border: #E2E6EC;
  --color-border-light: #F0F1F3;
  --color-border-dark: #CDD2DA;
  --color-text-primary: #1D2129;
  --color-text-regular: #4E5969;
  --color-text-secondary: #86909C;
  --color-text-placeholder: #C0C6CE;
  --color-text-inverse: #FFFFFF;
  --color-text-on-primary: #FFFFFF;

  /* State Colors */
  --state-success: #30A46C;
  --state-success-bg: #E8F8EF;
  --state-success-border: #9EE2B9;
  --state-warning: #F7BA1E;
  --state-warning-bg: #FFF8E6;
  --state-warning-border: #FDDEA0;
  --state-error: #E5484D;
  --state-error-bg: #FFECE8;
  --state-error-border: #FDADA8;
  --state-info: #1B9AA4;
  --state-info-bg: #E6F5F6;
  --state-info-border: #99D9DD;

  /* Typography System */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", "Courier New", monospace;
  --font-size-xs: 12px;
  --font-size-sm: 13px;
  --font-size-base: 14px;
  --font-size-md: 15px;
  --font-size-lg: 16px;
  --font-size-xl: 18px;
  --font-size-2xl: 20px;
  --font-size-3xl: 24px;
  --font-size-4xl: 28px;
  --font-size-5xl: 32px;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* Spacing System */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 12px;
  --spacing-lg: 16px;
  --spacing-xl: 20px;
  --spacing-2xl: 24px;
  --spacing-3xl: 32px;
  --spacing-4xl: 40px;
  --spacing-5xl: 48px;

  /* Radius System */
  --radius-sm: 2px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  --radius-full: 9999px;

  /* Surface & Depth */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.03);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.06);
  --shadow-float: 0 12px 32px rgba(0, 0, 0, 0.08);

  /* Layout */
  --sidebar-width: 220px;
  --sidebar-collapsed-width: 64px;
  --header-height: 56px;
  --content-max-width: 1400px;

  /* Component */
  --nav-height: 64px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-height) + 16px); }

body {
  min-height: 100vh;
  font-family: var(--font-family);
  background: var(--color-bg);
  color: var(--color-text-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a { color: inherit; }

.no-scrollbar::-webkit-scrollbar { display: none; }
.no-scrollbar { -ms-overflow-style: none; scrollbar-width: none; }

/* ── Layout ── */
.container {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-2xl);
}

/* ── Navigation ── */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  background: var(--color-bg-elevated);
  border-bottom: 1px solid var(--color-border);
  height: var(--nav-height);
  transition: box-shadow 0.3s;
}
.site-nav.nav-scrolled { box-shadow: var(--shadow-md); }

.nav-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-2xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  text-decoration: none;
}
.nav-brand img { width: 32px; height: 32px; border-radius: var(--radius-md); }
.nav-brand-name {
  display: flex;
  align-items: baseline;
  gap: var(--spacing-sm);
}
.nav-brand-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
}
.nav-brand-sub { font-size: var(--font-size-sm); color: var(--color-text-secondary); }

.nav-desktop-links {
  display: flex;
  align-items: center;
  gap: var(--spacing-3xl);
}

.nav-link {
  color: var(--color-text-regular);
  text-decoration: none;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  transition: color 0.2s;
  position: relative;
  padding: 4px 0;
}
.nav-link:hover { color: var(--color-primary); }
.nav-link.active { color: var(--color-primary); }
.nav-link.active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -6px;
  height: 2px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
}

/* 汉堡按钮（仅移动端显示） */
.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 40px; height: 40px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--color-text-primary);
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}
.nav-toggle:hover { background: var(--color-bg-hover); }
.nav-toggle:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }
.nav-toggle svg { width: 22px; height: 22px; }
.nav-toggle .icon-close { display: none; }
.nav-toggle[aria-expanded="true"] .icon-menu { display: none; }
.nav-toggle[aria-expanded="true"] .icon-close { display: block; }

/* 移动端下拉菜单 */
.mobile-menu {
  position: fixed;
  top: var(--nav-height);
  left: 0; right: 0;
  z-index: 49;
  background: var(--color-bg-elevated);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  padding: var(--spacing-lg) var(--spacing-2xl) var(--spacing-2xl);
  gap: var(--spacing-xs);
  opacity: 0;
  transform: translateY(-8px);
  pointer-events: none;
  visibility: hidden;
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s;
}
.mobile-menu.open {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
  visibility: visible;
}
.mobile-menu .nav-link {
  padding: var(--spacing-md) var(--spacing-sm);
  border-radius: var(--radius-md);
  font-size: var(--font-size-lg);
}
.mobile-menu .nav-link:hover { background: var(--color-bg-hover); }
.mobile-menu .nav-link.active::after { display: none; }
.mobile-menu .btn-primary { margin-top: var(--spacing-sm); }

/* ── Buttons ── */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  background: var(--color-primary);
  color: var(--color-text-on-primary);
  border: none;
  border-radius: var(--radius-lg);
  padding: 10px 24px;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  font-family: inherit;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.2s, transform 0.15s;
}
.btn-primary:hover { background: var(--color-primary-hover); transform: translateY(-1px); }
.btn-primary:active { background: var(--color-primary-active); transform: translateY(0); }
.btn-primary:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }

.btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  background: transparent;
  color: var(--color-primary);
  border: 1.5px solid var(--color-primary);
  border-radius: var(--radius-lg);
  padding: 10px 24px;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  font-family: inherit;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.2s, color 0.2s, transform 0.15s;
}
.btn-outline:hover { background: var(--color-primary); color: var(--color-text-on-primary); transform: translateY(-1px); }
.btn-outline:active { transform: translateY(0); }
.btn-outline:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }

.btn-white {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  background: var(--color-text-inverse);
  color: var(--color-primary);
  border: none;
  border-radius: var(--radius-lg);
  padding: 12px 32px;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  font-family: inherit;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.2s, transform 0.15s;
}
.btn-white:hover { background: var(--color-primary-lighter); transform: translateY(-1px); }
.btn-white:active { transform: translateY(0); }
.btn-white:focus-visible { outline: 2px solid var(--color-text-inverse); outline-offset: 2px; }

/* ── Section 通用 ── */
.section-title {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  text-align: center;
  line-height: var(--line-height-tight);
}
.section-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  text-align: center;
  margin-top: var(--spacing-lg);
  line-height: var(--line-height-normal);
}

/* ── Hero ── */
.hero {
  padding: 120px 0 80px;
  background: linear-gradient(135deg, var(--color-primary-lighter), var(--color-primary-bg));
}
.hero-content {
  display: flex;
  align-items: center;
  gap: var(--spacing-5xl);
}
.hero-text { flex: 1; max-width: 560px; }
.hero-title {
  font-size: 42px;
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  line-height: 1.2;
  letter-spacing: -0.5px;
}
.hero-subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-text-secondary);
  margin-top: var(--spacing-xl);
  line-height: var(--line-height-relaxed);
}
.hero-cta {
  display: flex;
  gap: var(--spacing-lg);
  margin-top: var(--spacing-3xl);
}
.hero-cta .btn-primary,
.hero-cta .btn-outline { padding: 14px 36px; font-size: var(--font-size-lg); }
.hero-image-container { flex: 1; max-width: 560px; }
.hero-image-container img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
}

/* ── Features ── */
.features-section { padding: 80px 0; }
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-2xl);
  margin-top: var(--spacing-5xl);
}
.security-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-2xl);
  margin-top: var(--spacing-5xl);
}

.feature-card {
  background: var(--color-bg-elevated);
  border-radius: var(--radius-xl);
  padding: var(--spacing-3xl);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.3s, transform 0.2s;
}
.feature-card:hover { box-shadow: var(--shadow-md); transform: translateY(-4px); }

.feature-icon-circle {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-full);
  background: var(--color-primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xl);
}
.feature-icon-circle svg { width: 28px; height: 28px; }

.feature-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-md);
}
.feature-desc {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: var(--line-height-normal);
}

/* ── Stats ── */
.stats-section { padding: 64px 0; background: var(--color-bg-inset); }
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-2xl);
  text-align: center;
}
.stat-number {
  font-size: 44px;
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  line-height: 1.1;
  font-variant-numeric: tabular-nums;
}
.stat-label {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  margin-top: var(--spacing-sm);
}

/* ── About ── */
.about-section { padding: 80px 0; }
.about-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--spacing-5xl);
  margin-top: var(--spacing-5xl);
  align-items: start;
}
.about-story-title {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-lg);
}
.about-story-text {
  font-size: var(--font-size-base);
  color: var(--color-text-regular);
  line-height: var(--line-height-relaxed);
}
.about-story-text + .about-story-text { margin-top: var(--spacing-lg); }
.about-value-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2xl);
}
.about-value-item {
  display: flex;
  gap: var(--spacing-lg);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  box-shadow: var(--shadow-xs);
  transition: box-shadow 0.3s, transform 0.2s;
}
.about-value-item:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.about-value-icon {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  background: var(--color-primary-light);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
}
.about-value-icon svg { width: 24px; height: 24px; }
.about-value-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-xs);
}
.about-value-desc {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: var(--line-height-normal);
}

/* ── CTA ── */
.cta-section { padding: 80px 0; background: var(--color-primary); }
.cta-title {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-on-primary);
  line-height: var(--line-height-tight);
}
.cta-subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-primary-light);
  margin-top: var(--spacing-lg);
  line-height: var(--line-height-normal);
}
.cta-actions { margin-top: var(--spacing-3xl); text-align: center; }

/* ── Footer ── */
.site-footer {
  background: var(--color-text-primary);
  padding: 56px 0 32px;
  color: var(--color-text-inverse);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-4xl);
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}
.footer-brand img { width: 32px; height: 32px; border-radius: var(--radius-md); }
.footer-brand span { font-size: var(--font-size-xl); font-weight: var(--font-weight-bold); }
.footer-desc {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  opacity: 0.8;
}
.footer-col-title {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-lg);
  color: var(--color-text-inverse);
}
.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}
.footer-link {
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: var(--font-size-base);
  opacity: 0.8;
  transition: opacity 0.2s, color 0.2s;
}
.footer-link:hover { opacity: 1; color: var(--color-primary-300); }
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  margin-top: var(--spacing-4xl);
  padding-top: var(--spacing-2xl);
  text-align: center;
}
.footer-copyright {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  opacity: 0.6;
}

/* ── 返回顶部 ── */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 48;
  width: 44px;
  height: 44px;
  border: none;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  color: var(--color-text-inverse);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-float);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.3s, transform 0.3s, visibility 0.3s, background 0.2s;
}
.back-to-top.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.back-to-top:hover { background: var(--color-primary-hover); }
.back-to-top:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }
.back-to-top svg { width: 20px; height: 20px; }

/* ── 动画 ── */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ── 响应式：≤1024px ── */
@media (max-width: 1024px) {
  .hero-content { flex-direction: column; text-align: center; }
  .hero-text { max-width: 100%; }
  .hero-cta { justify-content: center; }
  .hero-image-container { max-width: 480px; margin: 0 auto; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .security-grid { grid-template-columns: repeat(3, 1fr); }
  .nav-desktop-links { display: none; }
  .nav-toggle { display: inline-flex; }
  .about-grid { grid-template-columns: 1fr; gap: var(--spacing-4xl); }
}

/* ── 响应式：≤640px ── */
@media (max-width: 640px) {
  .container, .nav-inner { padding: 0 var(--spacing-lg); }
  .features-grid { grid-template-columns: 1fr; }
  .security-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); row-gap: var(--spacing-4xl); }
  .hero-cta { flex-direction: column; align-items: stretch; }
  .section-title { font-size: var(--font-size-3xl); }
  .cta-title { font-size: var(--font-size-3xl); }
  .footer-grid { grid-template-columns: 1fr; gap: var(--spacing-3xl); }
  .hero { padding: 96px 0 64px; }
  .hero-title { font-size: 30px; }
  .hero-subtitle { font-size: var(--font-size-lg); }
  .stat-number { font-size: 36px; }
  .back-to-top { right: 16px; bottom: 16px; }
}

/* ── 减弱动效偏好 ── */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .fade-in { opacity: 1; transform: none; transition: none; }
  .btn-primary, .btn-outline, .btn-white, .feature-card,
  .about-value-item, .back-to-top, .mobile-menu, .site-nav { transition: none; }
}