:root {
  --bg-primary: #0a0f1a;
  --bg-secondary: #101828;
  --bg-card: rgba(22, 32, 50, 0.72);
  --bg-glass: rgba(18, 28, 46, 0.55);
  --border-glass: rgba(120, 160, 220, 0.16);
  --border-soft: rgba(120, 160, 220, 0.1);
  --text-primary: #eaf1fb;
  --text-secondary: #9fb1cb;
  --text-muted: #6d7f99;
  --accent-1: #2f7bff;
  --accent-2: #7b5cff;
  --accent-3: #00d4c8;
  --accent-glow: rgba(47, 123, 255, 0.35);
  --gradient-hero: linear-gradient(135deg, #0b1226 0%, #14224a 38%, #2a1c5e 68%, #0d2a4a 100%);
  --gradient-accent: linear-gradient(120deg, #2f7bff 0%, #7b5cff 55%, #00d4c8 100%);
  --radius-lg: 22px;
  --radius-md: 16px;
  --radius-sm: 10px;
  --shadow-card: 0 18px 44px rgba(0, 0, 0, 0.38);
  --shadow-glow: 0 0 0 1px rgba(120, 160, 220, 0.12), 0 22px 60px rgba(10, 20, 45, 0.55);
  --font-sans: -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(0.22, 0.61, 0.36, 1);
}

@media (prefers-color-scheme: light) {
  :root {
    --bg-primary: #f4f7fc;
    --bg-secondary: #ffffff;
    --bg-card: rgba(255, 255, 255, 0.78);
    --bg-glass: rgba(255, 255, 255, 0.62);
    --border-glass: rgba(40, 80, 160, 0.14);
    --border-soft: rgba(40, 80, 160, 0.08);
    --text-primary: #16233a;
    --text-secondary: #4a5b75;
    --text-muted: #7a8aa3;
    --accent-glow: rgba(47, 123, 255, 0.22);
    --gradient-hero: linear-gradient(135deg, #e8f0ff 0%, #dfe7ff 38%, #ece4ff 68%, #e0f4f6 100%);
    --shadow-card: 0 16px 40px rgba(30, 60, 120, 0.12);
    --shadow-glow: 0 0 0 1px rgba(40, 80, 160, 0.1), 0 20px 50px rgba(30, 60, 120, 0.14);
  }
}

*,
*::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: 1.78;
  color: var(--text-primary);
  background:
    radial-gradient(1200px 600px at 12% -8%, rgba(47, 123, 255, 0.16), transparent 60%),
    radial-gradient(1000px 520px at 88% 4%, rgba(123, 92, 255, 0.14), transparent 62%),
    radial-gradient(900px 500px at 50% 100%, rgba(0, 212, 200, 0.08), transparent 65%),
    var(--bg-primary);
  background-attachment: fixed;
  min-height: 100vh;
  overflow-x: hidden;
}

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

a {
  color: var(--accent-1);
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

a:hover,
a:focus-visible {
  color: var(--accent-3);
}

::selection {
  background: rgba(47, 123, 255, 0.35);
  color: #fff;
}

/* ---------- Header / Nav ---------- */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(18px) saturate(150%);
  -webkit-backdrop-filter: blur(18px) saturate(150%);
  background: var(--bg-glass);
  border-bottom: 1px solid var(--border-glass);
  box-shadow: 0 10px 34px rgba(0, 0, 0, 0.22);
  animation: headerDrop 0.7s cubic-bezier(0.22, 0.61, 0.36, 1) both;
}

@keyframes headerDrop {
  from {
    opacity: 0;
    transform: translateY(-18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

header nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 14px 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  flex-wrap: wrap;
}

header nav > a {
  font-size: 1.22rem;
  font-weight: 800;
  letter-spacing: 0.5px;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  white-space: nowrap;
  transition: transform var(--transition), filter var(--transition);
}

header nav > a:hover {
  transform: scale(1.04);
  filter: drop-shadow(0 0 14px var(--accent-glow));
}

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

header nav ul li a {
  display: inline-block;
  padding: 7px 13px;
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  border: 1px solid transparent;
  transition: color var(--transition), background var(--transition), border-color var(--transition), transform var(--transition);
}

header nav ul li a:hover,
header nav ul li a:focus-visible {
  color: var(--text-primary);
  background: rgba(47, 123, 255, 0.14);
  border-color: var(--border-glass);
  transform: translateY(-2px);
}

/* ---------- Main / Hero ---------- */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 22px 80px;
}

main > h1 {
  position: relative;
  margin: 46px 0 20px;
  padding: 46px 40px 40px;
  font-size: clamp(1.65rem, 4vw, 2.6rem);
  line-height: 1.32;
  font-weight: 800;
  letter-spacing: 0.5px;
  border-radius: var(--radius-lg);
  background: var(--gradient-hero);
  border: 1px solid var(--border-glass);
  box-shadow: var(--shadow-glow);
  overflow: hidden;
  animation: heroIn 0.9s cubic-bezier(0.22, 0.61, 0.36, 1) both;
}

main > h1::before {
  content: "";
  position: absolute;
  inset: -40% -10% auto auto;
  width: 420px;
  height: 420px;
  background: radial-gradient(circle, rgba(123, 92, 255, 0.45), transparent 68%);
  filter: blur(10px);
  pointer-events: none;
  animation: floatGlow 9s ease-in-out infinite alternate;
}

main > h1::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 4px;
  width: 100%;
  background: var(--gradient-accent);
  opacity: 0.85;
}

@keyframes heroIn {
  from {
    opacity: 0;
    transform: translateY(26px) scale(0.985);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes floatGlow {
  from {
    transform: translate3d(0, 0, 0) scale(1);
  }
  to {
    transform: translate3d(-40px, 30px, 0) scale(1.12);
  }
}

main > h1 + p {
  margin: 0 0 46px;
  padding: 24px 28px;
  font-size: 1.02rem;
  color: var(--text-secondary);
  background: var(--bg-card);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-md);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: var(--shadow-card);
  animation: heroIn 1s 0.1s cubic-bezier(0.22, 0.61, 0.36, 1) both;
}

/* ---------- Sections ---------- */
section {
  position: relative;
  margin-bottom: 34px;
  padding: 34px 32px;
  background: var(--bg-card);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(16px) saturate(130%);
  -webkit-backdrop-filter: blur(16px) saturate(130%);
  box-shadow: var(--shadow-card);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  animation: sectionRise 0.8s cubic-bezier(0.22, 0.61, 0.36, 1) both;
  animation-timeline: view();
  animation-range: entry 0% entry 40%;
  scroll-margin-top: 96px;
}

@supports not (animation-timeline: view()) {
  section {
    animation: sectionRise 0.8s cubic-bezier(0.22, 0.61, 0.36, 1) both;
  }
}

@keyframes sectionRise {
  from {
    opacity: 0;
    transform: translateY(34px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

section:hover {
  border-color: rgba(47, 123, 255, 0.3);
  box-shadow: 0 0 0 1px rgba(47, 123, 255, 0.18), 0 26px 64px rgba(0, 0, 0, 0.42);
  transform: translateY(-3px);
}

section h2 {
  position: relative;
  margin: 0 0 22px;
  padding-left: 18px;
  font-size: clamp(1.3rem, 2.6vw, 1.72rem);
  font-weight: 800;
  letter-spacing: 0.4px;
  color: var(--text-primary);
}

section h2::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.18em;
  bottom: 0.18em;
  width: 5px;
  border-radius: 4px;
  background: var(--gradient-accent);
  box-shadow: 0 0 16px var(--accent-glow);
}

section h3 {
  margin: 30px 0 12px;
  font-size: 1.16rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.3px;
  transition: color var(--transition);
}

section h3:hover {
  color: var(--accent-3);
}

section h4 {
  margin: 20px 0 8px;
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--accent-1);
  letter-spacing: 0.2px;
}

section p {
  margin: 0 0 14px;
  color: var(--text-secondary);
  font-size: 0.98rem;
}

section h2 + p {
  color: var(--text-secondary);
}

/* ---------- Lists ---------- */
section ul {
  list-style: none;
  margin: 0 0 16px;
  padding: 0;
  display: grid;
  gap: 10px;
}

section ul li {
  position: relative;
  padding: 12px 16px 12px 42px;
  font-size: 0.95rem;
  color: var(--text-secondary);
  background: var(--bg-glass);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  transition: transform var(--transition), border-color var(--transition), background var(--transition), color var(--transition);
}

section ul li::before {
  content: "";
  position: absolute;
  left: 16px;
  top: 50%;
  width: 8px;
  height: 8px;
  margin-top: -4px;
  border-radius: 50%;
  background: var(--gradient-accent);
  box-shadow: 0 0 10px var(--accent-glow);
}

section ul li:hover {
  transform: translateX(5px);
  border-color: rgba(47, 123, 255, 0.32);
  background: rgba(47, 123, 255, 0.08);
  color: var(--text-primary);
}

section ul li strong {
  color: var(--text-primary);
  font-weight: 700;
}

section ul li a {
  color: var(--accent-1);
  font-weight: 500;
}

section ul li a:hover {
  color: var(--accent-3);
}

/* ---------- Articles ---------- */
article {
  position: relative;
  margin: 0 0 18px;
  padding: 22px 24px;
  background: var(--bg-glass);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

article::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--gradient-accent);
  opacity: 0;
  transition: opacity var(--transition);
}

article:hover {
  transform: translateY(-4px);
  border-color: rgba(123, 92, 255, 0.34);
  box-shadow: 0 18px 42px rgba(0, 0, 0, 0.34);
}

article:hover::before {
  opacity: 1;
}

article h3 {
  margin: 0 0 8px;
  font-size: 1.08rem;
  color: var(--text-primary);
}

article p {
  margin: 0 0 8px;
  font-size: 0.94rem;
  color: var(--text-secondary);
}

article p:first-of-type {
  display: inline-block;
  padding: 2px 12px;
  margin-bottom: 10px;
  font-size: 0.8rem;
  color: var(--accent-3);
  background: rgba(0, 212, 200, 0.1);
  border: 1px solid rgba(0, 212, 200, 0.22);
  border-radius: 999px;
  letter-spacing: 0.3px;
}

article a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent-1);
  transition: gap var(--transition), color var(--transition);
}

article a::after {
  content: "→";
  transition: transform var(--transition);
}

article a:hover {
  color: var(--accent-3);
  gap: 10px;
}

article a:hover::after {
  transform: translateX(3px);
}

/* ---------- Blockquote ---------- */
blockquote {
  margin: 20px 0 0;
  padding: 22px 26px;
  background: linear-gradient(135deg, rgba(47, 123, 255, 0.1), rgba(123, 92, 255, 0.08));
  border: 1px solid var(--border-glass);
  border-left: 4px solid var(--accent-2);
  border-radius: var(--radius-md);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: transform var(--transition), box-shadow var(--transition);
}

blockquote:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 36px rgba(0, 0, 0, 0.3);
}

blockquote p {
  position: relative;
  margin: 0 0 12px;
  padding-left: 22px;
  font-size: 0.96rem;
  font-style: italic;
  color: var(--text-secondary);
}

blockquote p:last-child {
  margin-bottom: 0;
}

blockquote p::before {
  content: "“";
  position: absolute;
  left: 0;
  top: -4px;
  font-size: 1.5rem;
  font-style: normal;
  font-weight: 800;
  color: var(--accent-3);
  opacity: 0.85;
}

/* ---------- FAQ ---------- */
#faq h3 {
  position: relative;
  margin: 26px 0 10px;
  padding: 14px 18px 14px 46px;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  background: var(--bg-glass);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  cursor: default;
  transition: transform var(--transition), border-color var(--transition), background var(--transition), box-shadow var(--transition);
}

#faq h3::before {
  content: "Q";
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  font-size: 0.76rem;
  font-weight: 800;
  color: #fff;
  background: var(--gradient-accent);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--accent-glow);
}

#faq h3:hover {
  transform: translateX(5px);
  border-color: rgba(47, 123, 255, 0.34);
  background: rgba(47, 123, 255, 0.08);
  box-shadow: 0 10px 26px rgba(0, 0, 0, 0.24);
}

#faq h3 + p {
  margin: 0 0 6px;
  padding: 16px 20px 16px 46px;
  font-size: 0.94rem;
  color: var(--text-secondary);
  background: rgba(0, 0, 0, 0.12);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  transition: border-color var(--transition), background var(--transition);
}

#faq h3 + p:hover {
  border-color: rgba(0, 212, 200, 0.24);
  background: rgba(0, 212, 200, 0.05);
}

/* ---------- HowTo ---------- */
#howto h4 {
  position: relative;
  margin: 22px 0 8px;
  padding: 12px 16px 12px 44px;
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--text-primary);
  background: var(--bg-glass);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  transition: transform var(--transition), border-color var(--transition), background var(--transition);
}

#howto h4::before {
  content: "✓";
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  font-size: 0.72rem;
  font-weight: 800;
  color: #fff;
  background: var(--gradient-accent);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--accent-glow);
}

#howto h4:hover {
  transform: translateX(5px);
  border-color: rgba(0, 212, 200, 0.34);
  background: rgba(0, 212, 200, 0.07);
}

#howto h4 + p {
  margin: 0 0 4px;
  padding-left: 44px;
  font-size: 0.94rem;
  color: var(--text-secondary);
}

/* ---------- Contact ---------- */
#contact ul {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

#contact ul li {
  padding: 14px 16px 14px 42px;
}

#contact h3 {
  margin-top: 32px;
}

#contact p:last-of-type {
  margin-top: 18px;
  padding: 16px 20px;
  font-size: 0.9rem;
  color: var(--text-muted);
  background: rgba(0, 0, 0, 0.14);
  border: 1px dashed var(--border-glass);
  border-radius: var(--radius-sm);
}

/* ---------- Footer ---------- */
footer {
  position: relative;
  padding: 30px 22px;
  text-align: center;
  background: var(--bg-glass);
  border-top: 1px solid var(--border-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

footer p {
  margin: 0;
  font-size: 0.88rem;
  color: var(--text-muted);
  letter-spacing: 0.4px;
  transition: color var(--transition);
}

footer p:hover {
  color: var(--text-secondary);
}

footer::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  height: 2px;
  width: 100%;
  background: var(--gradient-accent);
  opacity: 0.6;
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  header nav {
    padding: 12px 16px;
    gap: 10px;
  }

  header nav ul {
    width: 100%;
    justify-content: flex-start;
    overflow-x: auto;
    flex-wrap: nowrap;
    padding-bottom: 4px;
    scrollbar-width: none;
  }

  header nav ul::-webkit-scrollbar {
    display: none;
  }

  header nav ul li a {
    white-space: nowrap;
    font-size: 0.84rem;
    padding: 6px 11px;
  }

  main {
    padding: 0 16px 60px;
  }

  main > h1 {
    margin-top: 28px;
    padding: 32px 24px 30px;
  }

  main > h1 + p {
    padding: 20px;
    margin-bottom: 32px;
  }

  section {
    padding: 26px 20px;
    margin-bottom: 24px;
    border-radius: var(--radius-md);
  }

  #contact ul {
    grid-template-columns: 1fr;
  }

  article {
    padding: 18px 18px;
  }

  blockquote {
    padding: 18px 18px;
  }

  section:hover {
    transform: none;
  }
}

@media (max-width: 560px) {
  body {
    font-size: 15px;
    line-height: 1.72;
  }

  main > h1 {
    padding: 26px 18px 24px;
    border-radius: var(--radius-md);
  }

  main > h1 + p {
    padding: 16px;
    font-size: 0.94rem;
  }

  section {
    padding: 22px 16px;
  }

  section h2 {
    padding-left: 15px;
    font-size: 1.22rem;
  }

  section h3 {
    font-size: 1.04rem;
  }

  section ul li {
    padding: 11px 13px 11px 36px;
    font-size: 0.9rem;
  }

  section ul li::before {
    left: 13px;
  }

  #faq h3 {
    padding: 12px 14px 12px 42px;
    font-size: 0.94rem;
  }

  #faq h3 + p {
    padding: 14px 14px 14px 42px;
    font-size: 0.9rem;
  }

  #howto h4 {
    padding: 11px 13px 11px 40px;
    font-size: 0.92rem;
  }

  #howto h4 + p {
    padding-left: 40px;
    font-size: 0.9rem;
  }

  article h3 {
    font-size: 1rem;
  }

  blockquote p {
    font-size: 0.9rem;
  }
}

/* ---------- Accessibility / Motion ---------- */
@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;
  }
}

:focus-visible {
  outline: 2px solid var(--accent-3);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- Print ---------- */
@media print {
  header,
  footer {
    display: none;
  }

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

  section,
  main > h1,
  main > h1 + p,
  article,
  blockquote {
    box-shadow: none;
    border: 1px solid #ccc;
    background: #fff;
    color: #000;
    animation: none;
  }

  a {
    color: #000;
    text-decoration: underline;
  }
}