:root {
  --color-primary: #1a5fb4;
  --color-primary-dark: #144a8c;
  --color-primary-light: #4a8fe0;
  --color-accent: #2d7a4f;
  --color-accent-2: #8a3a6b;
  --color-bg: #f5f7fb;
  --color-bg-elevated: #ffffff;
  --color-surface: rgba(255, 255, 255, 0.72);
  --color-surface-strong: rgba(255, 255, 255, 0.92);
  --color-text: #1c2430;
  --color-text-soft: #4a5568;
  --color-text-muted: #6b7688;
  --color-border: rgba(26, 95, 180, 0.14);
  --color-border-strong: rgba(26, 95, 180, 0.28);
  --gradient-hero: linear-gradient(135deg, #1a5fb4 0%, #4a8fe0 45%, #8a3a6b 100%);
  --gradient-cta: linear-gradient(135deg, #1a5fb4 0%, #2d7a4f 100%);
  --shadow-sm: 0 2px 8px rgba(26, 95, 180, 0.08);
  --shadow-md: 0 8px 28px rgba(26, 95, 180, 0.12);
  --shadow-lg: 0 18px 48px rgba(26, 95, 180, 0.18);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-pill: 999px;
  --blur-glass: saturate(180%) blur(14px);
  --transition-base: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1200px;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
}

[data-theme="dark"] {
  --color-primary: #4a8fe0;
  --color-primary-dark: #1a5fb4;
  --color-primary-light: #7fb4f0;
  --color-bg: #0d1420;
  --color-bg-elevated: #16202e;
  --color-surface: rgba(22, 32, 46, 0.72);
  --color-surface-strong: rgba(22, 32, 46, 0.92);
  --color-text: #e6edf7;
  --color-text-soft: #b4c0d3;
  --color-text-muted: #8593a8;
  --color-border: rgba(74, 143, 224, 0.22);
  --color-border-strong: rgba(74, 143, 224, 0.4);
  --gradient-hero: linear-gradient(135deg, #0f2f5c 0%, #1a5fb4 45%, #5a2547 100%);
  --gradient-cta: linear-gradient(135deg, #4a8fe0 0%, #2d7a4f 100%);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 28px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 18px 48px rgba(0, 0, 0, 0.5);
}

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

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image:
    radial-gradient(circle at 12% 8%, rgba(74, 143, 224, 0.12), transparent 42%),
    radial-gradient(circle at 88% 12%, rgba(138, 58, 107, 0.1), transparent 40%),
    radial-gradient(circle at 50% 100%, rgba(45, 122, 79, 0.08), transparent 45%);
  background-attachment: fixed;
  transition: background-color var(--transition-base), color var(--transition-base);
  overflow-x: hidden;
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-base), opacity var(--transition-base);
}

a:hover,
a:focus-visible {
  color: var(--color-primary-light);
  text-decoration: underline;
  text-underline-offset: 3px;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: 4px;
}

h1, h2, h3, h4 {
  line-height: 1.35;
  color: var(--color-text);
  margin: 0 0 0.6em;
  font-weight: 700;
  letter-spacing: 0.01em;
}

h1 { font-size: clamp(1.7rem, 4.2vw, 2.6rem); }
h2 { font-size: clamp(1.35rem, 3vw, 1.9rem); }
h3 { font-size: clamp(1.1rem, 2.2vw, 1.35rem); }

p { margin: 0 0 1em; }

ul, ol {
  padding-left: 1.4em;
  margin: 0 0 1em;
}

li { margin-bottom: 0.4em; }

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

/* ============ Header ============ */
#site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-surface);
  backdrop-filter: var(--blur-glass);
  -webkit-backdrop-filter: var(--blur-glass);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  transition: background var(--transition-base), box-shadow var(--transition-base);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.7rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  flex-shrink: 0;
}

.brand a {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  text-decoration: none;
}

.brand svg {
  border-radius: 10px;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-base);
}

.brand a:hover svg {
  transform: rotate(-6deg) scale(1.06);
}

.brand-name {
  font-size: 1.35rem;
  font-weight: 800;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  letter-spacing: 0.04em;
}

.brand-slogan {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  padding: 0.15rem 0.6rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-surface-strong);
  white-space: nowrap;
}

#main-nav {
  flex: 1 1 auto;
  min-width: 0;
}

#main-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 0.15rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

#main-nav a {
  display: inline-block;
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius-pill);
  font-size: 0.9rem;
  color: var(--color-text-soft);
  text-decoration: none;
  transition: background var(--transition-base), color var(--transition-base), transform var(--transition-base);
}

#main-nav a:hover,
#main-nav a:focus-visible {
  background: rgba(74, 143, 224, 0.14);
  color: var(--color-primary);
  text-decoration: none;
  transform: translateY(-1px);
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

#site-search {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

#search-input {
  width: 180px;
  padding: 0.45rem 0.85rem;
  font-size: 0.88rem;
  font-family: inherit;
  color: var(--color-text);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  transition: border-color var(--transition-base), box-shadow var(--transition-base), width var(--transition-base);
}

#search-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(74, 143, 224, 0.2);
  width: 220px;
}

#site-search button,
#theme-toggle,
#menu-toggle {
  font-family: inherit;
  font-size: 0.85rem;
  padding: 0.45rem 0.95rem;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform var(--transition-base), box-shadow var(--transition-base), background var(--transition-base), color var(--transition-base);
}

#site-search button {
  background: var(--gradient-cta);
  color: #fff;
  font-weight: 600;
}

#theme-toggle {
  background: var(--color-bg-elevated);
  color: var(--color-text-soft);
  border-color: var(--color-border);
}

#menu-toggle {
  display: none;
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
}

#site-search button:hover,
#theme-toggle:hover,
#menu-toggle:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* ============ Breadcrumb ============ */
.breadcrumb {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.9rem 1.25rem 0;
}

.breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin: 0;
  padding: 0;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.breadcrumb li + li::before {
  content: "/";
  margin-right: 0.35rem;
  color: var(--color-border-strong);
}

.breadcrumb a {
  color: var(--color-text-soft);
  text-decoration: none;
}

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

/* ============ Main layout ============ */
#main-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.25rem 1.25rem 3rem;
}

#main-content > section {
  margin-bottom: 2.5rem;
  padding: 1.75rem;
  background: var(--color-surface);
  backdrop-filter: var(--blur-glass);
  -webkit-backdrop-filter: var(--blur-glass);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base), border-color var(--transition-base);
}

#main-content > section:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-border-strong);
}

#main-content > section > h2 {
  position: relative;
  padding-bottom: 0.55rem;
}

#main-content > section > h2::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 56px;
  height: 4px;
  border-radius: var(--radius-pill);
  background: var(--gradient-hero);
}

/* ============ Hero ============ */
.hero {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 1.75rem;
  align-items: stretch;
  padding: 0 !important;
  background: transparent !important;
  border: none !important;
  box-shadow: none !important;
  backdrop-filter: none !important;
  -webkit-backdrop-filter: none !important;
}

.hero-carousel {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-height: 280px;
  box-shadow: var(--shadow-lg);
  background: var(--gradient-hero);
}

.hero-carousel .slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  animation: heroFade 18s infinite;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-carousel .slide svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.slide-1 { animation-delay: 0s; }
.slide-2 { animation-delay: 6s; }
.slide-3 { animation-delay: 12s; }

@keyframes heroFade {
  0% { opacity: 0; transform: scale(1.04); }
  4% { opacity: 1; transform: scale(1); }
  29% { opacity: 1; transform: scale(1); }
  33% { opacity: 0; transform: scale(1.04); }
  100% { opacity: 0; transform: scale(1.04); }
}

.hero-text {
  padding: 1.75rem;
  background: var(--color-surface-strong);
  backdrop-filter: var(--blur-glass);
  -webkit-backdrop-filter: var(--blur-glass);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.hero-text h1 {
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.hero-lead {
  color: var(--color-text-soft);
  font-size: 0.98rem;
  text-align: justify;
}

.hero-stats {
  display: inline-block;
  font-size: 0.92rem;
  color: var(--color-text-soft);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-pill);
  background: rgba(74, 143, 224, 0.1);
  border: 1px dashed var(--color-border-strong);
  margin-bottom: 1rem;
}

.hero-stats span[data-count] {
  font-weight: 800;
  color: var(--color-primary);
  font-size: 1.05em;
}

.cta,
.cta-secondary {
  display: inline-block;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-pill);
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none;
  transition: transform var(--transition-base), box-shadow var(--transition-base), background var(--transition-base);
  margin: 0.25rem 0.5rem 0.25rem 0;
}

.cta {
  background: var(--gradient-cta);
  color: #fff;
  box-shadow: var(--shadow-md);
}

.cta-secondary {
  background: var(--color-bg-elevated);
  color: var(--color-primary);
  border: 1px solid var(--color-border-strong);
}

.cta:hover,
.cta-secondary:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  text-decoration: none;
}

.cta:hover { color: #fff; }
.cta-secondary:hover { color: var(--color-primary-dark); }

/* ============ News list ============ */
#news ul {
  list-style: none;
  padding: 0;
  display: grid;
  gap: 0.65rem;
}

#news li {
  padding: 0.75rem 1rem;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  font-size: 0.94rem;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

#news li:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-sm);
}

#news strong {
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

/* ============ Articles ============ */
#articles article {
  padding: 1.25rem 1.4rem;
  margin-bottom: 1rem;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

#articles article:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-border-strong);
}

#articles article h3 {
  color: var(--color-primary);
  margin-bottom: 0.35rem;
}

#articles article time {
  display: inline-block;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  padding: 0.1rem 0.6rem;
  border-radius: var(--radius-pill);
  background: rgba(74, 143, 224, 0.1);
  margin-bottom: 0.5rem;
}

#articles article a {
  display: inline-block;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.3rem 0.9rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-border-strong);
  transition: background var(--transition-base), color var(--transition-base), transform var(--transition-base);
}

#articles article a:hover {
  background: var(--gradient-cta);
  color: #fff;
  text-decoration: none;
  transform: translateX(3px);
}

/* ============ FAQ ============ */
#faq details {
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: 0.7rem;
  padding: 0.15rem 1rem;
  transition: box-shadow var(--transition-base), border-color var(--transition-base);
}

#faq details[open] {
  box-shadow: var(--shadow-sm);
  border-color: var(--color-border-strong);
}

#faq summary {
  cursor: pointer;
  font-weight: 600;
  padding: 0.85rem 0;
  color: var(--color-text);
  list-style: none;
  position: relative;
  padding-right: 2rem;
  transition: color var(--transition-base);
}

#faq summary::-webkit-details-marker { display: none; }

#faq summary::after {
  content: "+";
  position: absolute;
  right: 0.25rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.35rem;
  font-weight: 400;
  color: var(--color-primary);
  transition: transform var(--transition-base);
}

#faq details[open] summary::after {
  content: "−";
  transform: translateY(-50%) rotate(180deg);
}

#faq summary:hover { color: var(--color-primary); }

#faq details p {
  margin: 0 0 0.9rem;
  color: var(--color-text-soft);
  font-size: 0.94rem;
  animation: fadeSlide 0.35s ease both;
}

@keyframes fadeSlide {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ============ HowTo ============ */
#howto ol {
  counter-reset: howto;
  list-style: none;
  padding: 0;
  display: grid;
  gap: 0.6rem;
}

#howto ol li {
  counter-increment: howto;
  position: relative;
  padding: 0.7rem 1rem 0.7rem 3rem;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 0.94rem;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

#howto ol li::before {
  content: counter(howto);
  position: absolute;
  left: 0.85rem;
  top: 50%;
  transform: translateY(-50%);
  width: 1.6rem;
  height: 1.6rem;
  display: grid;
  place-items: center;
  font-size: 0.82rem;
  font-weight: 700;
  color: #fff;
  background: var(--gradient-hero);
  border-radius: 50%;
}

#howto ol li:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-sm);
}

/* ============ Contact ============ */
#contact address {
  font-style: normal;
  display: grid;
  gap: 0.5rem;
  padding: 1.1rem 1.25rem;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

#contact address p { margin: 0; font-size: 0.94rem; }

/* ============ Sitemap / Links ============ */
#sitemap ul,
#links ul {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

#sitemap li,
#links li {
  margin: 0;
}

#sitemap a,
#links a {
  display: inline-block;
  padding: 0.4rem 1rem;
  font-size: 0.88rem;
  border-radius: var(--radius-pill);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  color: var(--color-text-soft);
  text-decoration: none;
  transition: background var(--transition-base), color var(--transition-base), transform var(--transition-base), box-shadow var(--transition-base);
}

#sitemap a:hover,
#links a:hover {
  background: var(--gradient-cta);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
  text-decoration: none;
}

/* ============ Footer ============ */
footer {
  background: var(--color-surface);
  backdrop-filter: var(--blur-glass);
  -webkit-backdrop-filter: var(--blur-glass);
  border-top: 1px solid var(--color-border);
  padding: 2.25rem 1.25rem 1.5rem;
  margin-top: 1rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.75rem;
}

.footer-inner h2 {
  font-size: 1.05rem;
  margin-bottom: 0.6rem;
  color: var(--color-primary);
}

.footer-inner p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  margin: 0 0 0.5rem;
}

.footer-inner a {
  color: var(--color-text-soft);
}

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

/* ============ Back to top ============ */
#back-to-top {
  position: fixed;
  right: 1.25rem;
  bottom: 1.25rem;
  z-index: 90;
  padding: 0.65rem 1.1rem;
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  color: #fff;
  background: var(--gradient-cta);
  border: none;
  border-radius: var(--radius-pill);
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0.85;
  transition: transform var(--transition-base), box-shadow var(--transition-base), opacity var(--transition-base);
}

#back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  opacity: 1;
}

/* ============ Scroll reveal ============ */
@media (prefers-reduced-motion: no-preference) {
  #main-content > section {
    animation: revealUp 0.7s cubic-bezier(0.22, 0.61, 0.36, 1) both;
    animation-timeline: view();
    animation-range: entry 0% entry 40%;
  }

  @keyframes revealUp {
    from { opacity: 0; transform: translateY(28px); }
    to { opacity: 1; transform: translateY(0); }
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============ Responsive ============ */
@media (max-width: 1024px) {
  .hero {
    grid-template-columns: 1fr;
  }

  .hero-carousel {
    min-height: 240px;
  }

  #search-input {
    width: 140px;
  }

  #search-input:focus {
    width: 170px;
  }
}

@media (max-width: 820px) {
  .header-inner {
    gap: 0.75rem;
  }

  #menu-toggle {
    display: inline-block;
  }

  #main-nav {
    order: 3;
    flex-basis: 100%;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
  }

  #main-nav.is-open {
    max-height: 600px;
  }

  #main-nav ul {
    flex-direction: column;
    padding: 0.5rem 0;
    gap: 0.15rem;
  }

  #main-nav a {
    display: block;
    padding: 0.6rem 0.9rem;
    border-radius: var(--radius-sm);
  }

  .header-tools {
    margin-left: auto;
  }

  #site-search {
    display: none;
  }

  .brand-slogan {
    display: none;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 15px;
  }

  #main-content {
    padding: 0.9rem 0.85rem 2.5rem;
  }

  #main-content > section {
    padding: 1.15rem;
    margin-bottom: 1.75rem;
    border-radius: var(--radius-md);
  }

  .breadcrumb {
    padding: 0.7rem 0.85rem 0;
  }

  .hero-carousel {
    min-height: 190px;
  }

  .hero-text {
    padding: 1.15rem;
  }

  .hero-stats {
    display: block;
    font-size: 0.85rem;
    line-height: 1.9;
  }

  .cta,
  .cta-secondary {
    display: block;
    text-align: center;
    margin: 0.5rem 0;
  }

  #articles article {
    padding: 1rem;
  }

  #faq summary {
    font-size: 0.95rem;
  }

  #howto ol li {
    padding-left: 2.7rem;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }

  #back-to-top {
    right: 0.85rem;
    bottom: 0.85rem;
    padding: 0.55rem 0.9rem;
    font-size: 0.78rem;
  }
}

@media (max-width: 380px) {
  .brand-name {
    font-size: 1.15rem;
  }

  .brand svg {
    width: 34px;
    height: 34px;
  }
}

/* ============ Print ============ */
@media print {
  #site-header,
  #back-to-top,
  .header-tools,
  .hero-carousel {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
  }

  #main-content > section {
    box-shadow: none;
    border: 1px solid #ccc;
    break-inside: avoid;
  }
}