/* =============================================
   biying7811.com.cn — Site Kit 共享样式
   文件路径：/assets/site.css
   版本：V3.1
   ============================================= */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--c-navy);
  background-color: var(--c-ivory);
  background-image:
    linear-gradient(rgba(11, 31, 58, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(11, 31, 58, 0.03) 1px, transparent 1px);
  background-size: 32px 32px;
  -webkit-font-smoothing: antialiased;
}

:where(a) {
  color: var(--c-blue);
  text-decoration: none;
  transition: color var(--transition);
}

:where(a):hover {
  text-decoration: underline;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-head);
  line-height: 1.2;
  letter-spacing: 0.5px;
  color: var(--c-navy);
}

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

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

ul, ol {
  list-style: none;
}

:focus-visible {
  outline: 2px solid var(--c-orange);
  outline-offset: 2px;
}

/* ---------- CSS Variables ---------- */
:root {
  --c-navy: #0B1F3A;
  --c-blue: #1E6FD9;
  --c-orange: #FF6B2C;
  --c-gold: #F2B705;
  --c-ivory: #F5F7FA;
  --c-slate: #1A2634;
  --c-line: #D9DEE5;
  --c-green: #2E8B57;
  --font-head: "Oswald", "Arial Narrow", "Bahnschrift", "DIN Condensed", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
  --rail-w: 280px;
  --transition: 200ms ease-out;
  --container-max: 1280px;
}

@media (min-width: 901px) {
  body {
    padding-left: var(--rail-w);
  }
}

#main-content {
  scroll-margin-top: 24px;
}

section[id] {
  scroll-margin-top: 84px;
}

/* ---------- Skip Link ---------- */
.skip-link {
  position: absolute;
  top: -120px;
  left: 16px;
  z-index: 2000;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 20px;
  background: var(--c-orange);
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(11, 31, 58, 0.3);
}

.skip-link:hover {
  color: #fff;
  text-decoration: none;
}

.skip-link:focus {
  top: 16px;
}

/* ---------- Container / Section ---------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: 32px;
}

.section {
  padding-block: 72px;
}

.section-sm {
  padding-block: 40px;
}

.content {
  max-width: 820px;
}

.prose p {
  margin-bottom: 16px;
}

.prose a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose a:hover {
  color: var(--c-orange);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 10px 22px;
  border: 2px solid transparent;
  background: transparent;
  font-family: var(--font-head);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  cursor: pointer;
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 10px 100%, 0 calc(100% - 10px));
  transition: background var(--transition), border-color var(--transition), color var(--transition), transform var(--transition);
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-2px);
}

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

.btn-primary:hover {
  background: #e65a1e;
  border-color: #e65a1e;
  color: #fff;
}

.btn-ghost {
  border-color: rgba(255, 255, 255, 0.45);
  color: #fff;
}

.btn-ghost:hover {
  border-color: var(--c-orange);
  color: var(--c-orange);
}

.btn-sm {
  min-height: 40px;
  padding: 6px 16px;
  font-size: 13px;
}

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 1000;
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  background-color: var(--c-navy);
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 24px 24px;
  border-right: 1px solid rgba(255, 255, 255, 0.08);
  overflow-y: auto;
  overflow-x: hidden;
}

.site-header::before {
  content: "";
  flex: 0 0 4px;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--c-orange) 0%, var(--c-orange) 55%, var(--c-gold) 55%, var(--c-gold) 100%);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 24px 24px 8px;
  color: #fff;
}

.brand:hover {
  color: #fff;
  text-decoration: none;
}

.brand-mark {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 34px;
  padding: 0 8px;
  background: var(--c-orange);
  color: #fff;
  font-family: var(--font-head);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 1px;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%);
}

.brand-name {
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0.5px;
  line-height: 1.2;
}

.brand-version {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  padding: 2px 6px;
  background: var(--c-gold);
  color: var(--c-navy);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.5px;
  line-height: 1.4;
}

.brand-tagline {
  padding: 0 24px 16px;
  font-size: 13px;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.6);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  letter-spacing: 0.3px;
}

/* ---------- Nav Toggle ---------- */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 14px;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: #fff;
  font-family: var(--font-head);
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  cursor: pointer;
}

.nav-toggle:hover {
  border-color: var(--c-orange);
}

.nav-toggle-box {
  display: inline-flex;
  flex-direction: column;
  gap: 4px;
  width: 18px;
}

.nav-toggle-line {
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ---------- Nav ---------- */
.site-nav {
  margin-top: 20px;
}

.nav-list {
  display: flex;
  flex-direction: column;
}

.nav-link {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 24px;
  color: rgba(255, 255, 255, 0.78);
  font-family: var(--font-head);
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  border-left: 3px solid transparent;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.nav-link:hover {
  background: rgba(255, 255, 255, 0.06);
  color: #fff;
  text-decoration: none;
  border-left-color: var(--c-orange);
}

.nav-link[aria-current="page"] {
  background: linear-gradient(90deg, rgba(255, 107, 44, 0.14), transparent 70%);
  border-left-color: var(--c-orange);
  color: #fff;
}

.nav-index {
  font-family: var(--font-head);
  font-size: 12px;
  font-weight: 600;
  color: var(--c-gold);
  letter-spacing: 1px;
}

.header-actions {
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 24px;
}

/* ---------- Footer ---------- */
.site-footer {
  background: var(--c-slate);
  color: rgba(255, 255, 255, 0.8);
  margin-top: 80px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 48px;
  padding-block: 64px 48px;
}

.footer-logo-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.footer-logo {
  font-family: var(--font-head);
  font-size: 22px;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.5px;
}

.footer-version {
  display: inline-flex;
  align-items: center;
  padding: 2px 6px;
  background: var(--c-gold);
  color: var(--c-navy);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.footer-desc {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.6);
  margin-bottom: 16px;
}

.footer-trust {
  font-size: 13px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.55);
  max-width: 420px;
}

.footer-heading {
  font-family: var(--font-head);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--c-gold);
  padding-bottom: 8px;
  margin-bottom: 16px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.footer-list li {
  margin-bottom: 6px;
}

.footer-list a {
  display: inline-block;
  padding: 4px 0;
  color: rgba(255, 255, 255, 0.75);
  font-size: 15px;
  transition: color var(--transition), padding-left var(--transition);
}

.footer-list a:hover {
  color: var(--c-orange);
  padding-left: 4px;
  text-decoration: none;
}

.footer-note {
  margin-top: 16px;
  padding-left: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.55);
  border-left: 2px solid var(--c-gold);
}

.footer-contact-list li {
  padding: 4px 0;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.7);
}

.footer-service-note {
  margin-top: 8px;
  padding-top: 8px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  font-size: 13px;
  color: rgba(255, 255, 255, 0.55);
}

.footer-contact-btn {
  margin-top: 16px;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-block: 20px;
}

.footer-bottom-row {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 6px 24px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.55);
}

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  padding: 20px 0;
  font-size: 14px;
}

.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin: 0 8px;
  color: var(--c-line);
}

.breadcrumb-link {
  color: var(--c-blue);
}

.breadcrumb-current {
  color: var(--c-navy);
  font-weight: 600;
}

/* ---------- Section Heading ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
  color: var(--c-orange);
  font-family: var(--font-head);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";
  width: 24px;
  height: 2px;
  background: var(--c-orange);
}

.section-title {
  font-family: var(--font-head);
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--c-navy);
  margin-bottom: 8px;
}

.section-lead {
  font-size: 17px;
  line-height: 1.7;
  color: #3a4a5e;
  max-width: 640px;
}

/* ---------- Grid ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 24px;
}

.grid-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

/* ---------- Card ---------- */
.card {
  background: #fff;
  border: 1px solid var(--c-line);
  border-top: 3px solid var(--c-navy);
  padding: 24px;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  border-top-color: var(--c-orange);
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(11, 31, 58, 0.08);
}

/* ---------- Figure ---------- */
.figure {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--c-navy) 0%, var(--c-blue) 100%);
  aspect-ratio: 16 / 9;
}

.figure::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, transparent 35%, rgba(255, 107, 44, 0.18) 50%, transparent 65%);
  pointer-events: none;
}

/* ---------- Data / Score ---------- */
.score-card {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  padding: 16px 24px;
  background: var(--c-navy);
  color: #fff;
  font-family: var(--font-head);
  border-left: 4px solid var(--c-orange);
}

.score-number {
  font-size: 32px;
  font-weight: 700;
  color: var(--c-gold);
  font-variant-numeric: tabular-nums;
}

/* ---------- Utility ---------- */
.clip-diagonal {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
}

.hr-diagonal {
  height: 6px;
  border: 0;
  margin: 48px 0;
  background: linear-gradient(100deg, var(--c-orange) 0%, var(--c-orange) 25%, var(--c-gold) 25%, var(--c-gold) 50%, var(--c-navy) 50%, var(--c-navy) 100%);
}

/* ---------- Scroll Reveal ---------- */
.js-enabled [data-reveal] {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 600ms ease-out, transform 600ms ease-out;
}

.js-enabled [data-reveal].is-revealed {
  opacity: 1;
  transform: none;
}

/* ---------- Responsive ---------- */
@media (max-width: 1100px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 900px) {
  body {
    padding-left: 0;
  }

  .site-header {
    position: sticky;
    top: 0;
    bottom: auto;
    width: 100%;
    min-height: 64px;
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    overflow: visible;
    border-right: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .site-header::before {
    flex: 0 0 3px;
    width: 100%;
    height: 3px;
  }

  .brand {
    flex: 1 1 auto;
    padding: 8px 0;
  }

  .brand-mark {
    min-width: 40px;
    height: 30px;
    font-size: 13px;
  }

  .brand-name {
    font-size: 17px;
  }

  .brand-version {
    font-size: 10px;
  }

  .brand-tagline {
    display: none;
  }

  .header-actions {
    display: none;
  }

  .nav-toggle {
    display: inline-flex;
    flex: 0 0 auto;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    width: 100%;
    margin: 0;
    padding: 8px 0 24px;
    background: var(--c-navy);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.25);
    max-height: calc(100vh - 64px);
    overflow-y: auto;
    visibility: hidden;
    opacity: 0;
    transform: translateY(-8px);
    transition: opacity var(--transition), transform var(--transition), visibility var(--transition);
  }

  .site-nav[data-open] {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
  }

  .nav-link {
    padding: 14px 24px;
    font-size: 17px;
  }
}

@media (max-width: 600px) {
  .container {
    padding-inline: 20px;
  }

  .section {
    padding-block: 48px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-block: 48px 32px;
  }

  .footer-bottom-row {
    flex-direction: column;
  }
}

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

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

  .js-enabled [data-reveal] {
    opacity: 1;
    transform: none;
  }
}