/**
 * cosmic-ergonomic.css — VUC网站人体工学优化补丁
 * 依赖: style.css 的 CSS 变量体系 | 原则: 不改颜色,只优化间距/字号/行高/交互
 * 用法: 在 style.css 之后引入此文件
 */

/* ====== 1. 全局排版基础 (Critical) ====== */
:root {
  --font-xs: 0.8125rem; --font-sm: 0.875rem; --font-base: 1rem;
  --font-md: 1.125rem; --font-lg: 1.25rem; --font-xl: 1.5rem;
  --font-2xl: 2rem; --font-3xl: 2.5rem; --font-4xl: 3rem;
  --lh-none: 1; --lh-tight: 1.3; --lh-snug: 1.5;
  --lh-normal: 1.65; --lh-relaxed: 1.8; --lh-loose: 2;
  --space-1: 4px; --space-2: 8px; --space-3: 12px;
  --space-4: 16px; --space-5: 20px; --space-6: 24px;
  --space-8: 32px; --space-10: 40px; --space-12: 48px;
  --space-16: 64px; --space-20: 80px; --space-24: 96px;
  --radius-xs: 4px; --radius-sm: 8px; --radius-md: 12px;
  --radius-lg: 16px; --radius-xl: 24px; --radius-2xl: 32px;
  --radius-full: 9999px;
  --text-primary: #ffffff;
  --text-secondary: rgba(255,255,255,0.80);
  --text-muted: rgba(255,255,255,0.55);
  --text-dim: rgba(255,255,255,0.35);
  --text-inverse: #020810;
  --tap-target-min: 44px;
  --focus-ring: 0 0 0 3px rgba(99,179,237,0.5);
  --focus-ring-strong: 0 0 0 3px rgba(99,179,237,0.8);
}

body {
  font-size: var(--font-base);
  line-height: var(--lh-normal);
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

p, li, td, th, label, input, select, textarea { line-height: var(--lh-normal); }
a { line-height: inherit; }

/* ====== 2. 标题层级清晰化 ====== */
h1, .h1, h2, .h2, h3, .h3, h4, .h4, h5, .h5, h6, .h6 {
  line-height: var(--lh-tight); letter-spacing: 0.02em;
  font-weight: 700; color: var(--text-primary);
}
h1, .h1 { font-size: var(--font-2xl); font-weight: 800; margin-bottom: var(--space-4); letter-spacing: 0.01em; }
h2, .h2 { font-size: var(--font-xl); font-weight: 700; margin-bottom: var(--space-3); }
h3, .h3 { font-size: var(--font-lg); font-weight: 600; margin-bottom: var(--space-2); }
h4, .h4 { font-size: var(--font-md); font-weight: 600; margin-bottom: var(--space-2); }
h5, .h5 { font-size: var(--font-base); font-weight: 600; margin-bottom: var(--space-1); }
h6, .h6 { font-size: var(--font-sm); font-weight: 600; margin-bottom: var(--space-1); }

.hero-title, .section-title, .page-title {
  font-size: var(--font-2xl); font-weight: 800;
  line-height: var(--lh-tight); letter-spacing: 0.01em; margin-bottom: var(--space-4);
}
.subtitle, .sub-title {
  font-size: var(--font-lg); line-height: var(--lh-snug);
  color: var(--text-secondary); margin-bottom: var(--space-4);
}

.page-header, .hero, .hero-banner, .banner {
  padding-top: var(--space-16); padding-bottom: var(--space-16);
}
.page-header h1, .hero h1, .hero-banner h1 {
  font-size: var(--font-3xl); font-weight: 800; margin-bottom: var(--space-4);
}
.page-header p, .hero p, .hero-banner p {
  font-size: var(--font-lg); line-height: var(--lh-relaxed); color: var(--text-secondary);
}

/* ====== 3. 卡片组件呼吸感增强 ====== */
.card, .service-card, .product-card, .shop-item,
.feature-card, .pricing-card, .testimonial-card,
.info-card, .stat-card, .team-card, .blog-card,
.news-card, .portfolio-card, .gallery-item, .pr-item,
.vuc-card, .item-card, .preview-card, .overview-card {
  padding: var(--space-5) var(--space-6);
  margin-bottom: var(--space-4);
  border-radius: var(--radius-lg);
  transition: transform 0.3s cubic-bezier(0.25,0.46,0.45,0.94),
    box-shadow 0.3s ease, border-color 0.3s ease, background-color 0.3s ease;
  will-change: transform;
}

.card:hover, .service-card:hover, .product-card:hover,
.shop-item:hover, .feature-card:hover, .pricing-card:hover,
.testimonial-card:hover, .info-card:hover, .stat-card:hover,
.team-card:hover, .blog-card:hover, .news-card:hover,
.portfolio-card:hover, .vuc-card:hover, .item-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.4), 0 0 20px rgba(99,179,237,0.1);
}

.card-body, .card-content, .card-inner { padding: var(--space-4); }
.card-title, .card-heading { margin-bottom: var(--space-2); line-height: var(--lh-snug); }
.card-text, .card-description {
  line-height: var(--lh-normal); color: var(--text-secondary); margin-bottom: var(--space-3);
}
.card-grid, .card-list, .services-grid,
.products-grid, .pricing-grid, .features-grid { gap: var(--space-6); }

.card-img, .card-image, .card-thumb {
  border-radius: var(--radius-md); overflow: hidden; margin-bottom: var(--space-4);
}
.card-img img, .card-image img { width: 100%; height: auto; display: block; }

.card-footer, .card-actions {
  padding-top: var(--space-3); margin-top: var(--space-3);
  border-top: 1px solid rgba(255,255,255,0.08);
  display: flex; align-items: center; gap: var(--space-3);
}

.card-badge, .card-tag {
  position: absolute; top: var(--space-3); right: var(--space-3);
  padding: 4px 10px; font-size: var(--font-xs); font-weight: 600;
  border-radius: var(--radius-full);
}

/* ====== 4. 按钮可点击区域增大 ====== */
button, input[type="submit"], input[type="button"],
.btn, .button, .btn-primary, .btn-secondary,
.btn-ghost, .btn-outline, .nav-btn, .action-btn,
.cta-btn, .buy-btn, .add-cart-btn, .submit-btn,
.vuc-btn, .btn-action, .btn-main, .btn-cta {
  min-height: var(--tap-target-min); min-width: var(--tap-target-min);
  padding: 12px 28px; font-size: var(--font-base); font-weight: 600;
  line-height: 1.4; letter-spacing: 0.02em; border-radius: var(--radius-md);
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease,
    background-color 0.2s ease, border-color 0.2s ease, opacity 0.2s ease;
  will-change: transform; user-select: none;
  display: inline-flex; align-items: center; justify-content: center;
  gap: var(--space-2); text-decoration: none;
}

button:hover, input[type="submit"]:hover, input[type="button"]:hover,
.btn:hover, .button:hover {
  transform: translateY(-2px); box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}
button:active, input[type="submit"]:active, input[type="button"]:active,
.btn:active, .button:active {
  transform: translateY(0) scale(0.98);
}
button:focus-visible, input[type="submit"]:focus-visible,
input[type="button"]:focus-visible, .btn:focus-visible {
  outline: none; box-shadow: var(--focus-ring-strong), 0 4px 12px rgba(0,0,0,0.3);
}

.btn-sm, .btn-icon, .btn-small { min-height: 36px; min-width: 36px; padding: 6px 16px; font-size: var(--font-sm); }
.btn-lg, .btn-large { min-height: 52px; padding: 14px 36px; font-size: var(--font-md); }
.btn .icon, .button .icon, button .icon { font-size: 1.1em; }
.btn-block, .button-block { width: 100%; }

/* ====== 5. 表单元素优化 ====== */
input[type="text"], input[type="email"], input[type="password"],
input[type="number"], input[type="search"], input[type="tel"],
input[type="url"], input[type="date"], input[type="time"],
input[type="datetime-local"], textarea, select,
.form-control, .form-input, .input-field, .text-input {
  min-height: var(--tap-target-min); padding: 12px 16px;
  font-size: var(--font-base); line-height: var(--lh-normal);
  border-radius: var(--radius-md);
  transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
  width: 100%;
}
textarea { min-height: 120px; resize: vertical; }

input:focus, textarea:focus, select:focus,
.form-control:focus, .form-input:focus {
  outline: none; border-color: var(--steel-blue, #6ca0dc);
  box-shadow: 0 0 0 3px rgba(99,179,237,0.25), 0 0 12px rgba(99,179,237,0.2);
}

label, .form-label, .field-label {
  font-size: var(--font-sm); font-weight: 600; line-height: var(--lh-normal);
  margin-bottom: var(--space-2); display: block; color: var(--text-secondary);
}
.form-group, .form-field, .field-group, .form-row, .form-line {
  margin-bottom: var(--space-4); gap: var(--space-4);
}
input.error, input.is-error, textarea.error {
  border-color: #fc8181; box-shadow: 0 0 0 3px rgba(252,129,129,0.2);
}

input[type="checkbox"], input[type="radio"] {
  width: 18px; height: 18px; min-height: auto;
  accent-color: var(--steel-blue, #6ca0dc); cursor: pointer;
}

.form-hint, .help-text, .field-hint {
  font-size: var(--font-xs); color: var(--text-muted); margin-top: var(--space-1);
}

.search-box, .input-with-icon { position: relative; }
.search-box input, .input-with-icon input { padding-left: 40px; }
.search-box .icon, .input-with-icon .icon {
  position: absolute; left: 12px; top: 50%; transform: translateY(-50%);
  color: var(--text-muted); pointer-events: none;
}

select {
  appearance: none; -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23ffffff' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 12px center; padding-right: 36px;
}

/* ====== 6. 列表/表格行高优化 ====== */
li, .list-item, .nav-item, .menu-item, .dropdown-item {
  line-height: var(--lh-normal); padding: var(--space-2) 0;
}
li:hover, .list-item:hover, .nav-item:hover,
.menu-item:hover, .dropdown-item:hover {
  background-color: rgba(255,255,255,0.04); border-radius: var(--radius-sm);
  padding-left: var(--space-3); padding-right: var(--space-3);
  margin-left: calc(-1 * var(--space-3)); margin-right: calc(-1 * var(--space-3));
  transition: background-color 0.2s ease, padding 0.2s ease, margin 0.2s ease;
}

.feature-list, .check-list { list-style: none; padding-left: 0; }
.feature-list li, .check-list li {
  padding: var(--space-2) 0 var(--space-2) 28px; position: relative;
}
.feature-list li::before, .check-list li::before {
  content: "✓"; position: absolute; left: 0;
  color: var(--steel-blue, #6ca0dc); font-weight: 700;
}

table { border-collapse: separate; border-spacing: 0; width: 100%; font-size: var(--font-base); }
thead tr { background-color: rgba(255,255,255,0.05); }
tbody tr { transition: background-color 0.2s ease; }
tbody tr:hover { background-color: rgba(255,255,255,0.04); }
th, td { padding: var(--space-3) var(--space-4); line-height: var(--lh-normal); text-align: left; }
th { font-weight: 600; font-size: var(--font-sm); letter-spacing: 0.03em; text-transform: uppercase; color: var(--text-secondary); }
.table-wrapper, .table-container { border-radius: var(--radius-lg); overflow: hidden; }
.table-responsive { overflow-x: auto; -webkit-overflow-scrolling: touch; margin-bottom: var(--space-4); }
table .price, table .amount, table .number { text-align: right; font-variant-numeric: tabular-nums; }

/* ====== 7. 页面 Section 间距 ====== */
section, .section, .page-section, .content-section,
.hero-section, .features-section, .pricing-section,
.testimonials-section, .contact-section, .about-section,
.services-section, .products-section, .faq-section,
.news-section, .blog-section, .team-section {
  padding-top: var(--space-12); padding-bottom: var(--space-12);
}
.section-content, .section-body, .section-inner {
  padding-top: var(--space-8); padding-bottom: var(--space-8);
}

.section-header, .section-head { text-align: center; margin-bottom: var(--space-8); }
.section-header h2, .section-head h2 { font-size: var(--font-2xl); font-weight: 800; margin-bottom: var(--space-3); }
.section-header p, .section-head p {
  font-size: var(--font-lg); color: var(--text-secondary); max-width: 600px; margin: 0 auto;
}

section:nth-child(even), .section:nth-child(even) { background-color: rgba(255,255,255,0.01); }

.container, .page-container, .content-container,
.main-container, .site-container, .wrapper {
  max-width: 1200px; margin-left: auto; margin-right: auto;
  padding-left: var(--space-6); padding-right: var(--space-6);
}
.content-width, .article-content, .prose { max-width: 720px; margin-left: auto; margin-right: auto; }

p { margin-bottom: var(--space-4); line-height: var(--lh-relaxed); }
p:last-child { margin-bottom: 0; }
ul, ol { padding-left: var(--space-6); margin-bottom: var(--space-4); }
ul ul, ol ol, ul ol, ol ul { margin-bottom: 0; }
li { margin-bottom: var(--space-1); }

/* Header */
header, .header, .site-header, .navbar {
  padding: var(--space-4) 0; min-height: 64px; display: flex; align-items: center;
}
.header-inner, .navbar-inner {
  display: flex; align-items: center; justify-content: space-between; width: 100%;
}

/* Footer */
footer, .footer, .site-footer {
  padding-top: var(--space-16); padding-bottom: var(--space-8);
  font-size: var(--font-sm); color: var(--text-muted);
}
footer a, .footer a { color: var(--text-secondary); transition: color 0.2s ease; }
footer a:hover, .footer a:hover { color: var(--text-primary); }
.footer-links, .footer-nav { list-style: none; padding-left: 0; }
.footer-links li, .footer-nav li { padding: var(--space-1) 0; }

/* ====== 8. 动画性能优化 ====== */
.hover-lift, .card, .btn, .nav-item, .menu-item,
.dropdown-item, .pricing-card, .feature-card, .product-card,
.animate-on-scroll, .animated, .fade-in, .slide-up, .scale-in {
  will-change: transform;
}
.fixed-shadow, .card, .service-card, .modal, .dropdown, .tooltip {
  box-shadow: 0 4px 16px rgba(0,0,0,0.3), 0 1px 4px rgba(0,0,0,0.2);
}
.animated, .animate, .transitioning { transition-duration: 0.3s !important; }
.fast-transition { transition-duration: 0.15s !important; }
.slow-animation {
  transition-duration: 0.5s !important;
  transition-timing-function: cubic-bezier(0.25,0.46,0.45,0.94) !important;
}

.glow-on-hover { transition: opacity 0.3s ease, transform 0.3s ease; }
.glow-on-hover::after {
  content: ""; position: absolute; inset: 0; border-radius: inherit;
  box-shadow: 0 0 20px rgba(99,179,237,0.3); opacity: 0;
  transition: opacity 0.3s ease; pointer-events: none;
}
.glow-on-hover:hover::after { opacity: 1; }

.gpu-accelerated { transform: translateZ(0); backface-visibility: hidden; perspective: 1000px; }

/* ====== 9. 滚动条美化 ====== */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: rgba(255,255,255,0.03); border-radius: var(--radius-full); }
::-webkit-scrollbar-thumb {
  background: rgba(255,255,255,0.15); border-radius: var(--radius-full);
  border: 2px solid transparent; background-clip: padding-box; transition: background 0.2s ease;
}
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.25); background-clip: padding-box; }
::-webkit-scrollbar-thumb:active { background: rgba(255,255,255,0.35); background-clip: padding-box; }
::-webkit-scrollbar-corner { background: transparent; }
* { scrollbar-width: thin; scrollbar-color: rgba(255,255,255,0.2) rgba(255,255,255,0.03); }

/* ====== 10. 响应式断点微调 ====== */

/* 平板 ≤1024px */
@media screen and (max-width: 1024px) {
  :root {
    --font-3xl: 2.25rem; --font-2xl: 1.875rem;
    --font-xl: 1.375rem; --font-lg: 1.125rem; --font-md: 1rem;
  }
  section, .section { padding-top: var(--space-10); padding-bottom: var(--space-10); }
  .container, .page-container { padding-left: var(--space-5); padding-right: var(--space-5); }
  .page-header, .hero, .hero-banner { padding-top: var(--space-12); padding-bottom: var(--space-12); }
}

/* 小平板/大手机 ≤768px */
@media screen and (max-width: 768px) {
  :root {
    --font-3xl: 2rem; --font-2xl: 1.625rem; --font-xl: 1.25rem;
    --font-lg: 1.0625rem; --font-md: 1rem; --font-base: 0.9375rem;
    --lh-normal: 1.6; --lh-relaxed: 1.75;
  }
  body { font-size: var(--font-base); }
  h1, .h1 { margin-bottom: var(--space-3); }
  h2, .h2 { margin-bottom: var(--space-2); }
  section, .section { padding-top: var(--space-8); padding-bottom: var(--space-8); }
  .container, .page-container { max-width: 100%; padding-left: var(--space-4); padding-right: var(--space-4); }
  button, .btn { padding: 10px 20px; font-size: var(--font-sm); }
  input[type="text"], input[type="email"], input[type="password"],
  textarea, select { font-size: 16px; /* 防止iOS缩放 */ }
  .card, .service-card, .product-card, .shop-item { padding: var(--space-4); margin-bottom: var(--space-3); }
  table { font-size: var(--font-sm); }
  th, td { padding: var(--space-2) var(--space-3); }
  .card:hover, .service-card:hover { transform: none; }
  .page-header, .hero, .hero-banner { padding-top: var(--space-10); padding-bottom: var(--space-10); }
}

/* 手机 ≤480px */
@media screen and (max-width: 480px) {
  :root {
    --font-3xl: 1.75rem; --font-2xl: 1.5rem; --font-xl: 1.125rem;
    --font-lg: 1rem; --font-md: 0.9375rem; --font-base: 0.875rem;
    --lh-normal: 1.55; --lh-relaxed: 1.7;
  }
  body { font-size: var(--font-base); }
  section, .section { padding-top: var(--space-6); padding-bottom: var(--space-6); }
  .container, .page-container { padding-left: var(--space-3); padding-right: var(--space-3); }
  button, .btn { width: 100%; justify-content: center; padding: 14px 20px; }
  .btn-sm { width: auto; }
  .hide-mobile, .hidden-mobile { display: none !important; }
  .page-header, .hero, .hero-banner { padding-top: var(--space-8); padding-bottom: var(--space-8); }
}

@media (prefers-color-scheme: dark) { :root { color-scheme: dark; } }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important; animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important; scroll-behavior: auto !important;
  }
  .hover-lift, .card, .btn { transform: none !important; will-change: auto !important; }
}

/* ====== 11. 辅助功能增强 ====== */
.skip-link {
  position: absolute; top: -100%; left: var(--space-4); z-index: 9999;
  padding: var(--space-3) var(--space-4); background: var(--steel-blue, #6ca0dc);
  color: var(--text-inverse); font-weight: 700; border-radius: var(--radius-md);
  text-decoration: none; transition: top 0.2s ease;
}
.skip-link:focus { top: var(--space-4); outline: none; box-shadow: var(--focus-ring-strong); }
:focus:not(:focus-visible) { outline: none; }
:focus-visible { outline: none; box-shadow: var(--focus-ring); }
::selection { background-color: rgba(99,179,237,0.3); color: var(--text-primary); }

@media (prefers-contrast: high) {
  :root {
    --text-secondary: rgba(255,255,255,0.9);
    --text-muted: rgba(255,255,255,0.7);
    --text-dim: rgba(255,255,255,0.5);
  }
}

/* ====== 12. 内容阅读区优化 ====== */
.article-body, .article-text, .post-content,
.entry-content, .page-content { font-size: var(--font-base); line-height: var(--lh-relaxed); }
.article-body p, .post-content p { margin-bottom: var(--space-4); }

blockquote, .quote, .blockquote {
  padding: var(--space-4) var(--space-6); margin: var(--space-6) 0;
  border-left: 4px solid var(--steel-blue, #6ca0dc);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background-color: rgba(255,255,255,0.03);
  font-size: var(--font-lg); line-height: var(--lh-snug);
  font-style: italic; color: var(--text-secondary);
}
blockquote p:last-child { margin-bottom: 0; }

pre, .code-block, .code-wrapper {
  padding: var(--space-4); margin: var(--space-4) 0; border-radius: var(--radius-md);
  font-size: var(--font-sm); line-height: var(--lh-relaxed); overflow-x: auto;
}
code { font-size: 0.9em; line-height: var(--lh-normal); }

hr, .divider, .separator {
  border: none; height: 1px;
  background: linear-gradient(to right, transparent, rgba(255,255,255,0.15) 20%, rgba(255,255,255,0.15) 80%, transparent);
  margin: var(--space-8) 0;
}

img { max-width: 100%; height: auto; border-radius: var(--radius-md); }
figcaption, .image-caption, .img-caption {
  font-size: var(--font-xs); color: var(--text-muted);
  text-align: center; margin-top: var(--space-2); font-style: italic;
}

.badge, .tag, .label-chip {
  display: inline-flex; align-items: center; padding: 4px 10px;
  font-size: var(--font-xs); font-weight: 600; border-radius: var(--radius-full);
  letter-spacing: 0.03em; line-height: 1.4; min-height: 24px;
}

.breadcrumb, .breadcrumbs { font-size: var(--font-sm); color: var(--text-muted); line-height: var(--lh-normal); gap: var(--space-2); }
.breadcrumb a, .breadcrumbs a { color: var(--text-secondary); transition: color 0.2s ease; }
.breadcrumb a:hover { color: var(--text-primary); }

/* ====== 13. 导航与菜单 ====== */
nav, .navbar, .nav-menu, .main-nav, .site-nav { font-size: var(--font-sm); }
nav a, .nav-link, .menu-link {
  line-height: var(--lh-normal); padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm); transition: background-color 0.2s ease, color 0.2s ease;
}
.mobile-nav-toggle, .nav-toggle, .hamburger, .menu-toggle {
  min-width: var(--tap-target-min); min-height: var(--tap-target-min); padding: var(--space-2);
}
.dropdown-menu, .nav-dropdown, .submenu {
  padding: var(--space-2); border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(0,0,0,0.4);
}
.dropdown-item, .submenu-item {
  padding: var(--space-2) var(--space-3); border-radius: var(--radius-sm);
  line-height: var(--lh-normal); min-height: 40px; display: flex; align-items: center;
}
.dropdown-item:hover { transform: none; padding-left: var(--space-4); }

/* ====== 14. 常见组件 ====== */
.modal, .dialog, .popup {
  padding: var(--space-6); border-radius: var(--radius-xl);
  box-shadow: 0 24px 64px rgba(0,0,0,0.5), 0 0 40px rgba(99,179,237,0.1);
}
.modal-header { padding-bottom: var(--space-4); margin-bottom: var(--space-4); border-bottom: 1px solid rgba(255,255,255,0.1); }
.modal-body { line-height: var(--lh-normal); }
.modal-footer { padding-top: var(--space-4); margin-top: var(--space-4); border-top: 1px solid rgba(255,255,255,0.1); gap: var(--space-3); }

.toast, .notification, .alert { padding: var(--space-4); border-radius: var(--radius-md); line-height: var(--lh-normal); font-size: var(--font-sm); }
.tooltip { padding: var(--space-2) var(--space-3); font-size: var(--font-xs); border-radius: var(--radius-sm); line-height: var(--lh-normal); }

.pagination { gap: var(--space-1); }
.page-link, .pagination a, .pagination span {
  min-width: var(--tap-target-min); min-height: var(--tap-target-min);
  display: inline-flex; align-items: center; justify-content: center;
  padding: var(--space-2) var(--space-3); font-size: var(--font-sm);
  border-radius: var(--radius-sm); line-height: 1.4;
}

.progress-bar, .progress { height: 8px; border-radius: var(--radius-full); line-height: 1; }

.tab-list, .tabs, .nav-tabs { gap: var(--space-1); }
.tab-button, .tab-link, .nav-tab {
  padding: var(--space-3) var(--space-4); font-size: var(--font-sm); font-weight: 600;
  border-radius: var(--radius-md) var(--radius-md) 0 0; line-height: var(--lh-normal);
  min-height: var(--tap-target-min); transition: background-color 0.2s ease, color 0.2s ease;
}

.accordion-item, .faq-item { margin-bottom: var(--space-2); border-radius: var(--radius-md); }
.accordion-header, .faq-question {
  padding: var(--space-4); font-size: var(--font-md); font-weight: 600;
  min-height: var(--tap-target-min); cursor: pointer; transition: background-color 0.2s ease;
}
.accordion-body, .faq-answer {
  padding: var(--space-4) var(--space-5); line-height: var(--lh-normal); color: var(--text-secondary);
}

.price, .price-tag { font-size: var(--font-2xl); font-weight: 800; font-variant-numeric: tabular-nums; }
.price .currency { font-size: var(--font-md); vertical-align: super; }
.price .period { font-size: var(--font-sm); font-weight: 400; color: var(--text-muted); }

.stat-number, .counter { font-size: var(--font-3xl); font-weight: 800; font-variant-numeric: tabular-nums; line-height: var(--lh-none); }
.stat-label, .counter-label { font-size: var(--font-sm); color: var(--text-muted); margin-top: var(--space-1); }

/* ====== 15. 实用工具类 ====== */

/* ---- Flex 布局 ---- */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }
.flex-1 { flex: 1; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* ---- Grid 布局 ---- */
.grid { display: grid; }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

@media screen and (max-width: 768px) {
  .grid-cols-2, .grid-cols-3, .grid-cols-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media screen and (max-width: 480px) {
  .grid-cols-2, .grid-cols-3, .grid-cols-4 {
    grid-template-columns: 1fr;
  }
}

/* ---- 文本对齐 ---- */
.text-left { text-align: left; }
.text-center { text-align: center; }
.text-right { text-align: right; }

/* ---- 显示/隐藏 ---- */
.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }

/* ---- 定位 ---- */
.relative { position: relative; }
.absolute { position: absolute; }
.sticky { position: sticky; top: 0; z-index: 100; }

/* ---- 溢出 ---- */
.overflow-hidden { overflow: hidden; }
.overflow-auto { overflow: auto; }
.overflow-x-auto { overflow-x: auto; }

/* ---- 宽度 ---- */
.w-full { width: 100%; }
.max-w-none { max-width: none; }
.mx-auto { margin-left: auto; margin-right: auto; }

/* ---- 字间距 ---- */
.tracking-tight { letter-spacing: -0.01em; }
.tracking-normal { letter-spacing: 0; }
.tracking-wide { letter-spacing: 0.02em; }
.tracking-wider { letter-spacing: 0.05em; }

/* ---- 透明度 ---- */
.opacity-50 { opacity: 0.5; }
.opacity-75 { opacity: 0.75; }
.opacity-100 { opacity: 1; }

/* ---- 过渡动画 ---- */
.transition { transition: all 0.3s ease; }
.transition-fast { transition: all 0.15s ease; }
.transition-slow { transition: all 0.5s ease; }
.text-xs { font-size: var(--font-xs); } .text-sm { font-size: var(--font-sm); }
.text-base { font-size: var(--font-base); } .text-md { font-size: var(--font-md); }
.text-lg { font-size: var(--font-lg); } .text-xl { font-size: var(--font-xl); }
.text-2xl { font-size: var(--font-2xl); } .text-3xl { font-size: var(--font-3xl); }

.text-primary { color: var(--text-primary); } .text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); } .text-dim { color: var(--text-dim); }

.leading-tight { line-height: var(--lh-tight); } .leading-normal { line-height: var(--lh-normal); }
.leading-relaxed { line-height: var(--lh-relaxed); } .leading-loose { line-height: var(--lh-loose); }

.font-medium { font-weight: 500; } .font-semibold { font-weight: 600; }
.font-bold { font-weight: 700; } .font-extrabold { font-weight: 800; }

.mt-1 { margin-top: var(--space-1); } .mb-1 { margin-bottom: var(--space-1); }
.mt-2 { margin-top: var(--space-2); } .mb-2 { margin-bottom: var(--space-2); }
.mt-3 { margin-top: var(--space-3); } .mb-3 { margin-bottom: var(--space-3); }
.mt-4 { margin-top: var(--space-4); } .mb-4 { margin-bottom: var(--space-4); }
.mt-6 { margin-top: var(--space-6); } .mb-6 { margin-bottom: var(--space-6); }
.mt-8 { margin-top: var(--space-8); } .mb-8 { margin-bottom: var(--space-8); }
.mt-12 { margin-top: var(--space-12); } .mb-12 { margin-bottom: var(--space-12); }
.mx-4 { margin-left: var(--space-4); margin-right: var(--space-4); }
.my-4 { margin-top: var(--space-4); margin-bottom: var(--space-4); }
.my-8 { margin-top: var(--space-8); margin-bottom: var(--space-8); }
.my-12 { margin-top: var(--space-12); margin-bottom: var(--space-12); }

.p-4 { padding: var(--space-4); }
.p-6 { padding: var(--space-6); }
.px-4 { padding-left: var(--space-4); padding-right: var(--space-4); }
.py-4 { padding-top: var(--space-4); padding-bottom: var(--space-4); }
.py-8 { padding-top: var(--space-8); padding-bottom: var(--space-8); }
.pt-4 { padding-top: var(--space-4); } .pb-4 { padding-bottom: var(--space-4); }
.pt-8 { padding-top: var(--space-8); } .pb-8 { padding-bottom: var(--space-8); }
.pt-12 { padding-top: var(--space-12); } .pb-12 { padding-bottom: var(--space-12); }

.rounded-sm { border-radius: var(--radius-sm); } .rounded-md { border-radius: var(--radius-md); }
.rounded-lg { border-radius: var(--radius-lg); } .rounded-xl { border-radius: var(--radius-xl); }
.rounded-full { border-radius: var(--radius-full); }

.truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.line-clamp-2 { display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.line-clamp-3 { display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }

/*
 * 加载说明：在 <head> 中 style.css 之后引入：
 *   <link rel="stylesheet" href="css/style.css">
 *   <link rel="stylesheet" href="css/cosmic-ergonomic.css">
 */