:root {
  --brand: #6C5CE7;
  --brand-dark: #5A4BD1;
  --brand-light: #A29BFE;
  --accent: #E17055;
  --accent-2: #00B894;
  --accent-3: #FDCB6E;
  --bg: #F7F8FC;
  --bg-alt: #FFFFFF;
  --bg-elevated: rgba(255, 255, 255, 0.72);
  --text: #1A1A2E;
  --text-soft: #4A4A68;
  --text-muted: #7A7A96;
  --border: rgba(108, 92, 231, 0.14);
  --shadow-sm: 0 2px 8px rgba(26, 26, 46, 0.06);
  --shadow-md: 0 8px 24px rgba(26, 26, 46, 0.08);
  --shadow-lg: 0 16px 48px rgba(26, 26, 46, 0.12);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-xl: 32px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --max-width: 1180px;
  --transition: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0F0F1A;
    --bg-alt: #181828;
    --bg-elevated: rgba(24, 24, 40, 0.72);
    --text: #EDEDF5;
    --text-soft: #B8B8D0;
    --text-muted: #8888A8;
    --border: rgba(162, 155, 254, 0.16);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);
  }
}

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

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

body {
  margin: 0;
  padding: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

a:hover {
  color: var(--brand-light);
}

h1, h2, h3, h4, h5, h6 {
  margin: 1.4em 0 0.6em;
  line-height: 1.35;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
}

h1 { font-size: clamp(1.6rem, 4vw, 2.4rem); }
h2 { font-size: clamp(1.35rem, 3vw, 1.85rem); }
h3 { font-size: clamp(1.1rem, 2.2vw, 1.35rem); }

p {
  margin: 0 0 1em;
  color: var(--text-soft);
}

ul, ol {
  padding-left: 1.4em;
  color: var(--text-soft);
}

li {
  margin-bottom: 0.4em;
}

time {
  font-size: 0.85rem;
  color: var(--text-muted);
}

strong {
  color: var(--text);
  font-weight: 600;
}

/* ===== Skip Link ===== */
.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  z-index: 9999;
  padding: 10px 20px;
  background: var(--brand);
  color: #fff;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-weight: 600;
  transition: top var(--transition);
}

.skip-link:focus {
  top: 0;
  color: #fff;
}

.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 ===== */
header[role="banner"] {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-elevated);
  backdrop-filter: blur(18px) saturate(180%);
  -webkit-backdrop-filter: blur(18px) saturate(180%);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition), box-shadow var(--transition);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.02em;
  white-space: nowrap;
}

.logo:hover {
  color: var(--brand);
}

.logo svg {
  width: 40px;
  height: 40px;
  flex-shrink: 0;
  transition: transform var(--transition);
}

.logo:hover svg {
  transform: rotate(-8deg) scale(1.06);
}

.nav-menu {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: wrap;
  flex: 1;
}

.nav-menu li {
  margin: 0;
}

.nav-menu a {
  display: block;
  padding: 8px 14px;
  border-radius: var(--radius-md);
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-soft);
  transition: background var(--transition), color var(--transition), transform var(--transition);
}

.nav-menu a:hover {
  background: rgba(108, 92, 231, 0.1);
  color: var(--brand);
  transform: translateY(-2px);
}

/* ===== Search ===== */
.search-form {
  display: flex;
  align-items: center;
  gap: 0;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.search-form:focus-within {
  border-color: var(--brand);
  box-shadow: 0 0 0 4px rgba(108, 92, 231, 0.14);
}

.search-form input[type="search"] {
  border: none;
  outline: none;
  background: transparent;
  padding: 9px 16px;
  font-size: 0.9rem;
  font-family: var(--font);
  color: var(--text);
  width: 190px;
  transition: width var(--transition);
}

.search-form input[type="search"]::placeholder {
  color: var(--text-muted);
}

.search-form input[type="search"]:focus {
  width: 240px;
}

.search-form button {
  border: none;
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #fff;
  padding: 9px 18px;
  font-size: 0.9rem;
  font-family: var(--font);
  font-weight: 600;
  cursor: pointer;
  transition: opacity var(--transition), transform var(--transition);
}

.search-form button:hover {
  opacity: 0.9;
}

.search-form button:active {
  transform: scale(0.97);
}

.menu-toggle {
  display: none;
  border: 1px solid var(--border);
  background: var(--bg-alt);
  color: var(--text);
  font-size: 1.3rem;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition), transform var(--transition);
}

.menu-toggle:hover {
  background: rgba(108, 92, 231, 0.1);
  transform: scale(1.05);
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 14px 20px 0;
}

.breadcrumb ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.breadcrumb li {
  margin: 0;
  display: flex;
  align-items: center;
}

.breadcrumb li + li::before {
  content: "/";
  margin: 0 8px;
  color: var(--text-muted);
  opacity: 0.6;
}

.breadcrumb a {
  color: var(--text-muted);
}

.breadcrumb a:hover {
  color: var(--brand);
}

.breadcrumb [aria-current="page"] {
  color: var(--text);
  font-weight: 600;
}

/* ===== Main ===== */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px 60px;
}

main > section {
  margin-bottom: 48px;
  animation: fadeUp 0.7s ease both;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===== Banner ===== */
.banner {
  position: relative;
  margin: 20px 0 40px;
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  background: var(--brand);
}

.banner-slide {
  display: none;
  position: relative;
}

.banner-slide.active {
  display: block;
  animation: bannerFade 0.6s ease both;
}

@keyframes bannerFade {
  from {
    opacity: 0;
    transform: scale(1.02);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.banner-slide svg {
  width: 100%;
  height: auto;
  display: block;
}

.banner-dots {
  position: absolute;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 2;
}

.banner-dots button {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.6);
  background: rgba(255, 255, 255, 0.25);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), border-color var(--transition);
}

.banner-dots button:hover {
  background: rgba(255, 255, 255, 0.45);
  transform: scale(1.12);
}

.banner-dots button[aria-selected="true"] {
  background: #fff;
  color: var(--brand);
  border-color: #fff;
}

/* ===== Hero Intro ===== */
.hero-intro {
  background: linear-gradient(135deg, rgba(108, 92, 231, 0.08), rgba(162, 155, 254, 0.04));
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.hero-intro h1 {
  margin-top: 0;
  background: linear-gradient(135deg, var(--brand), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: var(--brand);
}

/* ===== Section Cards ===== */
main > section:not(.banner):not(.hero-intro) {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
}

main > section:not(.banner):not(.hero-intro):hover {
  box-shadow: var(--shadow-md);
}

main > section > h2 {
  margin-top: 0;
  position: relative;
  padding-bottom: 12px;
}

main > section > h2::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 56px;
  height: 4px;
  border-radius: 4px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
}

/* ===== Articles ===== */
#news article,
#articles article {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px 22px;
  margin-bottom: 16px;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

#news article:hover,
#articles article:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(108, 92, 231, 0.35);
}

#news article h3,
#articles article h3 {
  margin-top: 0;
  font-size: 1.1rem;
}

#news article h3 a,
#articles article h3 a {
  color: var(--text);
}

#news article h3 a:hover,
#articles article h3 a:hover {
  color: var(--brand);
}

#articles article a[href^="#article"] {
  display: inline-block;
  margin-top: 6px;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 6px 16px;
  border-radius: var(--radius-lg);
  background: rgba(108, 92, 231, 0.1);
  color: var(--brand);
  transition: background var(--transition), transform var(--transition), color var(--transition);
}

#articles article a[href^="#article"]:hover {
  background: var(--brand);
  color: #fff;
  transform: translateX(4px);
}

/* ===== FAQ ===== */
#faq details {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: box-shadow var(--transition), border-color var(--transition);
}

#faq details[open] {
  border-color: rgba(108, 92, 231, 0.4);
  box-shadow: var(--shadow-sm);
}

#faq summary {
  cursor: pointer;
  padding: 16px 20px;
  font-weight: 600;
  font-size: 1rem;
  color: var(--text);
  list-style: none;
  position: relative;
  padding-right: 48px;
  transition: background var(--transition), color var(--transition);
}

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

#faq summary::after {
  content: "+";
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.4rem;
  font-weight: 400;
  color: var(--brand);
  transition: transform var(--transition);
  line-height: 1;
}

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

#faq summary:hover {
  background: rgba(108, 92, 231, 0.06);
  color: var(--brand);
}

#faq details p {
  padding: 0 20px 18px;
  margin: 0;
  font-size: 0.94rem;
  animation: fadeUp 0.4s ease both;
}

/* ===== HowTo ===== */
#howto ol {
  counter-reset: howto;
  list-style: none;
  padding-left: 0;
}

#howto ol li {
  counter-increment: howto;
  position: relative;
  padding: 14px 18px 14px 56px;
  margin-bottom: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: transform var(--transition), box-shadow var(--transition);
}

#howto ol li::before {
  content: counter(howto);
  position: absolute;
  left: 16px;
  top: 14px;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #fff;
  font-size: 0.85rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

#howto ol li:hover {
  transform: translateX(6px);
  box-shadow: var(--shadow-sm);
}

/* ===== Sitemap & Links ===== */
#sitemap ul,
#links ul {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

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

#sitemap a,
#links a {
  display: inline-block;
  padding: 7px 16px;
  border-radius: var(--radius-lg);
  background: rgba(108, 92, 231, 0.08);
  border: 1px solid var(--border);
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-soft);
  transition: background var(--transition), color var(--transition), transform var(--transition), border-color var(--transition);
}

#sitemap a:hover,
#links a:hover {
  background: var(--brand);
  color: #fff;
  border-color: var(--brand);
  transform: translateY(-3px);
}

/* ===== Contact ===== */
#contact p {
  margin-bottom: 0.5em;
}

/* ===== Footer ===== */
footer[role="contentinfo"] {
  background: linear-gradient(180deg, var(--bg-alt), var(--bg));
  border-top: 1px solid var(--border);
  padding: 48px 20px 32px;
  margin-top: 20px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  text-align: center;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.footer-brand svg {
  width: 40px;
  height: 40px;
  transition: transform var(--transition);
}

.footer-brand svg:hover {
  transform: rotate(10deg) scale(1.1);
}

.footer-brand p {
  margin: 0;
  font-weight: 600;
  color: var(--text);
  font-size: 0.95rem;
}

footer nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 20px;
}

footer nav li {
  margin: 0;
}

footer nav a {
  font-size: 0.9rem;
  color: var(--text-muted);
  position: relative;
  padding-bottom: 2px;
}

footer nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--brand);
  border-radius: 2px;
  transition: width var(--transition);
}

footer nav a:hover {
  color: var(--brand);
}

footer nav a:hover::after {
  width: 100%;
}

.copyright {
  margin: 0;
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ===== Back to Top ===== */
#back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 900;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #fff;
  font-size: 1.3rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity var(--transition), visibility var(--transition), transform var(--transition), box-shadow var(--transition);
}

#back-to-top:hover {
  transform: translateY(-4px) scale(1.06);
  box-shadow: var(--shadow-lg);
}

#back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .nav-inner {
    gap: 12px;
  }

  .nav-menu {
    order: 3;
    flex-basis: 100%;
    justify-content: center;
    padding-top: 8px;
    border-top: 1px solid var(--border);
    margin-top: 4px;
  }

  .search-form {
    margin-left: auto;
  }

  .search-form input[type="search"] {
    width: 150px;
  }

  .search-form input[type="search"]:focus {
    width: 180px;
  }
}

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

  .nav-inner {
    padding: 10px 14px;
  }

  .logo span {
    font-size: 1.05rem;
  }

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

  .nav-menu {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    padding: 8px 0 0;
  }

  .nav-menu.open {
    display: flex;
  }

  .nav-menu a {
    padding: 10px 14px;
    text-align: center;
  }

  .menu-toggle {
    display: block;
    margin-left: auto;
  }

  .search-form {
    order: 4;
    flex-basis: 100%;
    margin-left: 0;
  }

  .search-form input[type="search"] {
    width: 100%;
    flex: 1;
  }

  .search-form input[type="search"]:focus {
    width: 100%;
  }

  .breadcrumb {
    padding: 10px 14px 0;
  }

  main {
    padding: 0 14px 40px;
  }

  main > section:not(.banner):not(.hero-intro) {
    padding: 22px 18px;
    border-radius: var(--radius-md);
  }

  .hero-intro {
    padding: 24px 18px;
  }

  .banner {
    border-radius: var(--radius-lg);
    margin: 14px 0 28px;
  }

  .banner-dots {
    bottom: 10px;
    gap: 7px;
  }

  .banner-dots button {
    width: 28px;
    height: 28px;
    font-size: 0.72rem;
  }

  #news article,
  #articles article {
    padding: 16px 16px;
  }

  #faq summary {
    padding: 14px 16px;
    padding-right: 44px;
    font-size: 0.94rem;
  }

  #faq summary::after {
    right: 16px;
  }

  #faq details p {
    padding: 0 16px 14px;
  }

  #howto ol li {
    padding: 12px 14px 12px 48px;
  }

  #howto ol li::before {
    left: 12px;
    top: 12px;
    width: 24px;
    height: 24px;
    font-size: 0.78rem;
  }

  footer[role="contentinfo"] {
    padding: 36px 14px 24px;
  }

  #back-to-top {
    right: 14px;
    bottom: 14px;
    width: 42px;
    height: 42px;
    font-size: 1.1rem;
  }
}

/* ===== Reduced Motion ===== */
@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;
  }
}

/* ===== Print ===== */
@media print {
  header[role="banner"],
  footer[role="contentinfo"],
  #back-to-top,
  .banner-dots,
  .search-form,
  .menu-toggle {
    display: none !important;
  }

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

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