/* Design tokens — 通达电商官网 */
:root {
  --color-primary-50: #f0fdfa;
  --color-primary-100: #ccfbf1;
  --color-primary-500: #0d9488;
  --color-primary-600: #0f766e;
  --color-primary-700: #115e59;
  --color-accent-500: #ea580c;
  --color-accent-600: #c2410c;
  --color-surface: #fafaf9;
  --color-surface-elevated: #ffffff;
  --color-text: #1c1917;
  --color-text-muted: #57534e;
  --color-border: #e7e5e4;
  --color-hero-glow: rgba(13, 148, 136, 0.12);

  --font-sans: "Noto Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: clamp(2rem, 4vw + 1rem, 3rem);

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-24: 6rem;

  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.25rem;

  --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.06);
  --shadow-md: 0 8px 24px rgb(0 0 0 / 0.08);
  --shadow-lg: 0 20px 50px rgb(0 0 0 / 0.12);

  --transition-fast: 150ms ease;
  --transition-normal: 280ms ease;

  --header-h: 4rem;
  --focus-ring: 2px solid var(--color-primary-500);
  --focus-offset: 2px;
}

[data-theme="dark"] {
  color-scheme: dark;
  --color-surface: #0c0a09;
  --color-surface-elevated: #1c1917;
  --color-text: #fafaf9;
  --color-text-muted: #a8a29e;
  --color-border: #292524;
  --color-hero-glow: rgba(45, 212, 191, 0.08);
  --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.4);
  --shadow-md: 0 8px 24px rgb(0 0 0 / 0.45);
  --shadow-lg: 0 20px 50px rgb(0 0 0 / 0.55);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --color-surface: #0c0a09;
    --color-surface-elevated: #1c1917;
    --color-text: #fafaf9;
    --color-text-muted: #a8a29e;
    --color-border: #292524;
    --color-hero-glow: rgba(45, 212, 191, 0.08);
    --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.4);
    --shadow-md: 0 8px 24px rgb(0 0 0 / 0.45);
    --shadow-lg: 0 20px 50px rgb(0 0 0 / 0.55);
  }
}

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-surface);
}

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

.skip-link {
  position: absolute;
  left: var(--space-4);
  top: var(--space-4);
  padding: var(--space-2) var(--space-4);
  background: var(--color-primary-700);
  color: #fff;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  z-index: 100;
  transform: translateY(-120%);
  transition: transform var(--transition-fast);
}

.skip-link:focus {
  transform: translateY(0);
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
}

.container {
  width: 100%;
  max-width: 72rem;
  margin-inline: auto;
  padding-inline: clamp(var(--space-4), 4vw, var(--space-8));
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  background: color-mix(in srgb, var(--color-surface-elevated) 92%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  height: var(--header-h);
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: inherit;
  font-weight: 700;
}

.logo:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
  border-radius: var(--radius-sm);
}

.logo-mark {
  display: grid;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--radius-md);
  background: linear-gradient(145deg, var(--color-primary-500), var(--color-primary-700));
  color: #fff;
  font-size: var(--font-size-sm);
}

.logo-text {
  font-size: var(--font-size-lg);
  letter-spacing: 0.02em;
}

.nav {
  display: flex;
  align-items: center;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-elevated);
  cursor: pointer;
}

.nav-toggle:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
}

.nav-toggle-bar {
  display: block;
  width: 1.25rem;
  height: 2px;
  margin-inline: auto;
  background: var(--color-text);
  border-radius: 1px;
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-6);
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-list a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-weight: 500;
  font-size: var(--font-size-sm);
  padding: var(--space-2) 0;
  border-bottom: 2px solid transparent;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.nav-list a:hover {
  color: var(--color-primary-600);
}

.nav-list a:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
  border-radius: var(--radius-sm);
}

.theme-toggle {
  display: inline-grid;
  place-items: center;
  width: 2.75rem;
  height: 2.75rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background: var(--color-surface-elevated);
  cursor: pointer;
  color: var(--color-text);
  font-size: var(--font-size-lg);
  line-height: 1;
}

.theme-toggle:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
}

.theme-icon--moon {
  display: none;
}

[data-theme="dark"] .theme-icon--sun {
  display: none;
}

[data-theme="dark"] .theme-icon--moon {
  display: inline;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-icon--sun {
    display: none;
  }

  :root:not([data-theme="light"]) .theme-icon--moon {
    display: inline;
  }
}

@media (max-width: 767px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav-list {
    position: absolute;
    right: var(--space-4);
    top: calc(var(--header-h) + var(--space-2));
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    min-width: 12rem;
    padding: var(--space-2);
    background: var(--color-surface-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-6px);
    transition: opacity var(--transition-normal), transform var(--transition-normal),
      visibility var(--transition-normal);
  }

  .nav-list.is-open {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
  }

  .nav-list li a {
    display: block;
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
  }

  .nav-list li a:hover {
    background: var(--color-surface);
  }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0 var(--space-6);
  font-family: inherit;
  font-weight: 600;
  font-size: var(--font-size-sm);
  text-decoration: none;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast),
    box-shadow var(--transition-fast), transform var(--transition-fast);
}

.btn:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
}

.btn--primary {
  background: var(--color-primary-600);
  color: #fff;
  box-shadow: var(--shadow-sm);
}

.btn--primary:hover {
  background: var(--color-primary-700);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn--secondary {
  background: transparent;
  color: var(--color-primary-700);
  border: 2px solid var(--color-primary-500);
}

[data-theme="dark"] .btn--secondary {
  color: var(--color-primary-100);
}

.btn--secondary:hover {
  background: var(--color-primary-50);
}

[data-theme="dark"] .btn--secondary:hover {
  background: rgb(45 212 191 / 0.12);
}

/* Hero */
.hero {
  position: relative;
  padding: var(--space-16) 0 var(--space-24);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: radial-gradient(
      ellipse 80% 60% at 70% 0%,
      var(--color-hero-glow),
      transparent 55%
    ),
    radial-gradient(ellipse 60% 50% at 10% 40%, rgb(234 88 12 / 0.06), transparent 50%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
}

.hero-eyebrow {
  margin: 0 0 var(--space-4);
  font-size: var(--font-size-sm);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-primary-600);
}

.hero-title {
  margin: 0 0 var(--space-6);
  font-size: var(--font-size-5xl);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.hero-accent {
  color: var(--color-accent-600);
}

.hero-lead {
  margin: 0 0 var(--space-8);
  max-width: 40rem;
  font-size: var(--font-size-lg);
  color: var(--color-text-muted);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

/* Sections */
.section {
  padding: var(--space-16) 0;
}

.section--alt {
  background: var(--color-surface-elevated);
  border-block: 1px solid var(--color-border);
}

.section-head {
  text-align: center;
  max-width: 40rem;
  margin: 0 auto var(--space-12);
}

.section-head--left {
  text-align: left;
  margin-left: 0;
}

.section-title {
  margin: 0 0 var(--space-4);
  font-size: var(--font-size-3xl);
  font-weight: 700;
}

.section-desc {
  margin: 0;
  color: var(--color-text-muted);
  font-size: var(--font-size-lg);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
  gap: var(--space-6);
}

.category-card {
  padding: var(--space-6);
  background: var(--color-surface-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-normal), transform var(--transition-normal);
}

.section--alt .category-card {
  background: var(--color-surface);
}

.category-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.category-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 3rem;
  height: 3rem;
  padding: 0 var(--space-3);
  margin-bottom: var(--space-4);
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-primary-100), transparent);
  color: var(--color-primary-700);
  font-weight: 700;
  font-size: var(--font-size-sm);
}

.category-title {
  margin: 0 0 var(--space-3);
  font-size: var(--font-size-xl);
}

.category-body {
  margin: 0;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.service-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: var(--space-6);
}

.service-item {
  display: flex;
  gap: var(--space-6);
  padding: var(--space-6);
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
}

.service-icon {
  flex-shrink: 0;
  font-size: 1.75rem;
  line-height: 1;
}

.service-title {
  margin: 0 0 var(--space-2);
  font-size: var(--font-size-xl);
}

.service-body {
  margin: 0;
  color: var(--color-text-muted);
}

.about-grid {
  display: grid;
  gap: var(--space-12);
  align-items: start;
}

@media (min-width: 900px) {
  .about-grid {
    grid-template-columns: 1.2fr 1fr;
  }
}

.about-panel {
  padding: var(--space-8);
  border-radius: var(--radius-xl);
  background: linear-gradient(160deg, var(--color-primary-50), var(--color-surface-elevated));
  border: 1px solid var(--color-border);
}

[data-theme="dark"] .about-panel {
  background: linear-gradient(160deg, rgb(45 212 191 / 0.08), var(--color-surface-elevated));
}

.about-panel-title {
  margin: 0 0 var(--space-4);
  font-size: var(--font-size-xl);
}

.about-panel-list {
  margin: 0;
  padding-left: var(--space-6);
  color: var(--color-text-muted);
}

.about-panel-list li {
  margin-bottom: var(--space-3);
}

.contact-section .contact-inner {
  display: grid;
  gap: var(--space-8);
}

@media (min-width: 768px) {
  .contact-section .contact-inner {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }
}

.contact-card {
  margin: 0;
  padding: var(--space-8);
  font-style: normal;
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-border);
  background: var(--color-surface-elevated);
  box-shadow: var(--shadow-sm);
}

.contact-card p {
  margin: 0 0 var(--space-4);
}

.contact-tel {
  font-weight: 600;
  color: var(--color-primary-600);
  text-decoration: none;
  margin-inline-start: var(--space-1);
}

.contact-tel:hover {
  text-decoration: underline;
}

.contact-tel:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
  border-radius: var(--radius-sm);
}

[data-theme="dark"] .contact-tel {
  color: var(--color-primary-100);
}

.site-footer {
  padding: var(--space-8) 0;
  border-top: 1px solid var(--color-border);
  background: var(--color-surface-elevated);
}

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

.footer-brand {
  margin: 0 0 var(--space-2);
  font-weight: 600;
}

.footer-meta {
  margin: 0 0 var(--space-2);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.footer-beian {
  margin: 0;
  font-size: var(--font-size-sm);
}

.footer-beian a {
  color: var(--color-text-muted);
  text-decoration: none;
}

.footer-beian a:hover {
  text-decoration: underline;
  color: var(--color-primary-600);
}

.footer-beian a:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
  border-radius: var(--radius-sm);
}

[data-theme="dark"] .footer-beian a:hover {
  color: var(--color-primary-100);
}