:root {
  --brand: #1a1a2e;
  --brand-2: #16213e;
  --accent: #e94560;
  --accent-2: #f5a623;
  --accent-glow: rgba(233, 69, 96, 0.35);
  --text: #222;
  --muted: #666;
  --bg: #fff;
  --bg-soft: #f7f8fc;
  --card: #f7f8fc;
  --glass: rgba(255, 255, 255, 0.72);
  --glass-border: rgba(255, 255, 255, 0.55);
  --border: #e4e6ef;
  --shadow-sm: 0 4px 14px rgba(26, 26, 46, 0.07);
  --shadow-md: 0 12px 32px rgba(26, 26, 46, 0.1);
  --shadow-lg: 0 20px 48px rgba(26, 26, 46, 0.16);
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 22px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

[data-theme="dark"] {
  --brand: #0d0d17;
  --brand-2: #12122a;
  --accent: #ff5c78;
  --accent-2: #ffc04d;
  --accent-glow: rgba(255, 92, 120, 0.35);
  --text: #eaeaf2;
  --muted: #a0a0b8;
  --bg: #0b0b14;
  --bg-soft: #10101f;
  --card: #15152a;
  --glass: rgba(21, 21, 42, 0.68);
  --glass-border: rgba(255, 255, 255, 0.09);
  --border: #26264a;
  --shadow-sm: 0 4px 14px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 12px 32px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 20px 48px rgba(0, 0, 0, 0.6);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background 0.35s var(--ease), color 0.35s var(--ease);
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.25s var(--ease);
}

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
}

::selection {
  background: var(--accent);
  color: #fff;
}

::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-soft);
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, var(--accent), var(--accent-2));
  border-radius: 999px;
  border: 2px solid var(--bg-soft);
}

.container {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== Header ===== */
header.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: linear-gradient(135deg, rgba(26, 26, 46, 0.92), rgba(22, 33, 62, 0.92));
  backdrop-filter: blur(18px) saturate(180%);
  -webkit-backdrop-filter: blur(18px) saturate(180%);
  color: #fff;
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.22);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

[data-theme="dark"] header.site-header {
  background: linear-gradient(135deg, rgba(13, 13, 23, 0.94), rgba(18, 18, 42, 0.94));
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 20px;
  max-width: 1180px;
  margin: 0 auto;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 20px;
  letter-spacing: 0.5px;
  color: #fff;
  flex: 0 0 auto;
}

.logo .mark {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  box-shadow: 0 6px 18px var(--accent-glow);
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease);
}

.logo:hover .mark {
  transform: rotate(-8deg) scale(1.06);
  box-shadow: 0 10px 26px var(--accent-glow);
}

.logo .mark svg {
  width: 22px;
  height: 22px;
}

nav.main-nav ul {
  display: flex;
  gap: 22px;
  list-style: none;
  font-size: 15px;
}

nav.main-nav a {
  opacity: 0.9;
  padding: 6px 2px;
  border-bottom: 2px solid transparent;
  transition: opacity 0.25s var(--ease), border-color 0.25s var(--ease), color 0.25s var(--ease);
}

nav.main-nav a:hover {
  opacity: 1;
  border-bottom-color: var(--accent);
  color: var(--accent-2);
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.search-box {
  display: flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.14);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-radius: 999px;
  padding: 4px 6px 4px 14px;
  transition: border-color 0.3s var(--ease), background 0.3s var(--ease);
}

.search-box:focus-within {
  border-color: var(--accent);
  background: rgba(255, 255, 255, 0.18);
}

.search-box input {
  border: 0;
  background: transparent;
  color: #fff;
  outline: none;
  font-size: 14px;
  width: 130px;
}

.search-box input::placeholder {
  color: rgba(255, 255, 255, 0.6);
}

.search-box button {
  border: 0;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  border-radius: 999px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 600;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.search-box button:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 16px var(--accent-glow);
}

.icon-btn {
  border: 0;
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  border-radius: 10px;
  width: 38px;
  height: 38px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.25s var(--ease), transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.icon-btn:hover {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  transform: translateY(-2px);
  box-shadow: 0 8px 20px var(--accent-glow);
}

.mobile-toggle {
  display: none;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
  font-size: 13px;
  color: var(--muted);
}

.breadcrumb .container {
  padding: 10px 20px;
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  align-items: center;
}

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

/* ===== Hero ===== */
.hero {
  position: relative;
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 45%, #2a1a3e 100%);
  color: #fff;
  overflow: hidden;
}

[data-theme="dark"] .hero {
  background: linear-gradient(135deg, #0d0d17 0%, #12122a 45%, #1c0f2e 100%);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 80% 18%, rgba(233, 69, 96, 0.32), transparent 55%),
    radial-gradient(circle at 8% 82%, rgba(245, 166, 35, 0.2), transparent 52%),
    radial-gradient(circle at 50% 120%, rgba(120, 60, 200, 0.22), transparent 60%);
  pointer-events: none;
  animation: heroGlow 14s ease-in-out infinite alternate;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 56px 56px;
  pointer-events: none;
  mask-image: radial-gradient(circle at 50% 40%, #000 20%, transparent 78%);
  -webkit-mask-image: radial-gradient(circle at 50% 40%, #000 20%, transparent 78%);
}

@keyframes heroGlow {
  0% {
    opacity: 0.85;
    transform: scale(1);
  }
  100% {
    opacity: 1;
    transform: scale(1.08);
  }
}

.hero-inner {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 40px;
  align-items: center;
  padding: 64px 20px;
  max-width: 1180px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 40px;
  line-height: 1.3;
  margin-bottom: 18px;
  letter-spacing: 1px;
  animation: fadeUp 0.9s var(--ease) both;
}

.hero h1 .hl {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero p.lead {
  font-size: 17px;
  opacity: 0.92;
  margin-bottom: 26px;
  max-width: 560px;
  animation: fadeUp 0.9s 0.12s var(--ease) both;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  animation: fadeUp 0.9s 0.22s var(--ease) both;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 26px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  border: 0;
  transition: transform 0.28s var(--ease), box-shadow 0.28s var(--ease), background 0.28s var(--ease);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  box-shadow: 0 8px 24px var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 34px var(--accent-glow);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.28);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.2);
  transform: translateY(-3px);
}

.hero-stats {
  display: flex;
  gap: 28px;
  margin-top: 34px;
  flex-wrap: wrap;
  animation: fadeUp 0.9s 0.32s var(--ease) both;
}

.hero-stats .stat strong {
  display: block;
  font-size: 26px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-stats .stat span {
  font-size: 13px;
  opacity: 0.75;
}

.hero-visual {
  position: relative;
  animation: fadeUp 0.9s 0.2s var(--ease) both;
}

.hero-visual .frame {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: var(--glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  transition: transform 0.5s var(--ease), box-shadow 0.5s var(--ease);
}

.hero-visual .frame:hover {
  transform: translateY(-6px) scale(1.015);
  box-shadow: 0 32px 72px rgba(0, 0, 0, 0.55);
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(26px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* ===== Sections ===== */
section {
  padding: 64px 0;
}

section.alt {
  background: var(--bg-soft);
}

.section-head {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 42px;
}

.section-head h2 {
  font-size: 30px;
  margin-bottom: 12px;
  position: relative;
  display: inline-block;
  line-height: 1.4;
}

.section-head h2::after {
  content: "";
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  bottom: -10px;
  width: 56px;
  height: 4px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
}

.section-head p {
  color: var(--muted);
  margin-top: 22px;
  font-size: 15px;
}

/* ===== Grid ===== */
.grid {
  display: grid;
  gap: 24px;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

/* ===== Card ===== */
.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease), border-color 0.35s var(--ease), background 0.35s var(--ease);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, rgba(233, 69, 96, 0.06), rgba(245, 166, 35, 0.06));
  opacity: 0;
  transition: opacity 0.35s var(--ease);
  pointer-events: none;
}

.card:hover::before {
  opacity: 1;
}

section.alt .card {
  background: var(--bg);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent);
}

.card h3 {
  font-size: 18px;
  margin-bottom: 10px;
}

.card h4 {
  font-size: 15px;
  margin: 14px 0 6px;
  color: var(--accent);
}

.card p {
  font-size: 14.5px;
  color: var(--muted);
}

.card p + p {
  margin-top: 10px;
}

.card .ico {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: linear-gradient(135deg, rgba(233, 69, 96, 0.14), rgba(245, 166, 35, 0.14));
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  transition: transform 0.35s var(--ease);
}

.card:hover .ico {
  transform: scale(1.08) rotate(-4deg);
}

.card .ico svg {
  width: 26px;
  height: 26px;
}

/* ===== Article list ===== */
.article-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}

.article-item {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.article-item:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.article-item .meta {
  font-size: 12.5px;
  color: var(--muted);
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

.article-item h3 {
  font-size: 17px;
  line-height: 1.5;
}

.article-item p {
  font-size: 14px;
  color: var(--muted);
  flex: 1;
}

.article-item .read {
  color: var(--accent);
  font-weight: 600;
  font-size: 14px;
  transition: letter-spacing 0.3s var(--ease), color 0.3s var(--ease);
}

.article-item:hover .read {
  letter-spacing: 1px;
  color: var(--accent-2);
}

.tag {
  display: inline-block;
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 999px;
  background: rgba(233, 69, 96, 0.12);
  color: var(--accent);
  font-weight: 600;
}

/* ===== FAQ ===== */
.faq-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  margin-bottom: 12px;
  overflow: hidden;
  background: var(--bg);
  transition: border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.faq-item:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-sm);
}

.faq-item.open {
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}

.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: 0;
  padding: 18px 22px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  color: var(--text);
  transition: color 0.25s var(--ease), background 0.25s var(--ease);
}

.faq-q:hover {
  color: var(--accent);
}

.faq-q .arrow {
  transition: transform 0.35s var(--ease);
  flex: 0 0 auto;
  color: var(--accent);
}

.faq-item.open .faq-q .arrow {
  transform: rotate(180deg);
}

.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s var(--ease), padding 0.4s var(--ease);
  padding: 0 22px;
  color: var(--muted);
  font-size: 14.5px;
}

.faq-item.open .faq-a {
  max-height: 600px;
  padding-bottom: 20px;
}

/* ===== HowTo steps ===== */
.howto-steps {
  counter-reset: step;
}

.howto-steps li {
  position: relative;
  padding: 18px 20px 18px 66px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 14px;
  margin-bottom: 14px;
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.howto-steps li:hover {
  transform: translateX(6px);
  border-color: var(--accent);
  box-shadow: var(--shadow-sm);
}

.howto-steps li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 18px;
  top: 18px;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 15px;
  box-shadow: 0 6px 16px var(--accent-glow);
}

.howto-steps li h4 {
  margin-bottom: 6px;
  font-size: 16px;
}

.howto-steps li p {
  font-size: 14px;
  color: var(--muted);
}

/* ===== Reveal animation ===== */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  will-change: opacity, transform;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ===== Contact ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 32px;
}

.contact-list {
  display: grid;
  gap: 16px;
}

.contact-list li {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg);
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.contact-list li:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-sm);
}

.contact-list .ci {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: linear-gradient(135deg, rgba(233, 69, 96, 0.14), rgba(245, 166, 35, 0.14));
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  transition: transform 0.3s var(--ease);
}

.contact-list li:hover .ci {
  transform: scale(1.08);
}

.contact-list .ci svg {
  width: 22px;
  height: 22px;
}

.contact-list strong {
  display: block;
  font-size: 15px;
}

.contact-list span {
  font-size: 14px;
  color: var(--muted);
}

/* ===== Footer ===== */
.footer-links {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}

.footer-links h4 {
  font-size: 15px;
  margin-bottom: 14px;
  color: #fff;
}

.footer-links ul {
  display: grid;
  gap: 9px;
}

.footer-links a {
  font-size: 13.5px;
  color: rgba(255, 255, 255, 0.7);
  transition: color 0.25s var(--ease), padding-left 0.25s var(--ease);
}

.footer-links a:hover {
  color: var(--accent-2);
  padding-left: 4px;
}

footer.site-footer {
  background: linear-gradient(135deg, #1a1a2e, #16213e);
  color: rgba(255, 255, 255, 0.8);
  padding: 52px 0 26px;
  font-size: 14px;
  position: relative;
  overflow: hidden;
}

[data-theme="dark"] footer.site-footer {
  background: linear-gradient(135deg, #0d0d17, #12122a);
}

footer.site-footer::before {
  content: "";
  position: absolute;
  top: -60%;
  right: -10%;
  width: 480px;
  height: 480px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(233, 69, 96, 0.14), transparent 70%);
  pointer-events: none;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  margin-top: 36px;
  padding-top: 22px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.6);
}

.footer-bottom a {
  color: rgba(255, 255, 255, 0.72);
}

.footer-bottom a:hover {
  color: var(--accent-2);
}

/* ===== Back to top ===== */
.back-top {
  position: fixed;
  right: 22px;
  bottom: 26px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  border: 0;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 10px 26px var(--accent-glow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: opacity 0.35s var(--ease), visibility 0.35s var(--ease), transform 0.35s var(--ease);
  z-index: 1200;
}

.back-top.show {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.back-top:hover {
  transform: translateY(-4px) scale(1.06);
  box-shadow: 0 16px 34px var(--accent-glow);
}

/* ===== Table ===== */
.table-wrap {
  overflow-x: auto;
  border-radius: 12px;
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  background: var(--bg);
}

th,
td {
  padding: 13px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  color: #fff;
  font-weight: 600;
}

tr:nth-child(even) td {
  background: var(--bg-soft);
}

tr:hover td {
  background: rgba(233, 69, 96, 0.06);
}

/* ===== Sitemap list links ===== */
#sitemap-links .card ul a {
  color: var(--muted);
  transition: color 0.25s var(--ease), padding-left 0.25s var(--ease);
}

#sitemap-links .card ul a:hover {
  color: var(--accent);
  padding-left: 4px;
}

/* ===== Responsive: 980px ===== */
@media (max-width: 980px) {
  .hero-inner {
    grid-template-columns: 1fr;
    padding: 44px 20px;
  }

  .hero h1 {
    font-size: 30px;
  }

  .hero p.lead {
    max-width: 100%;
  }

  .grid-3,
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

  .footer-links {
    grid-template-columns: repeat(2, 1fr);
  }

  nav.main-nav {
    position: fixed;
    top: 62px;
    left: 0;
    right: 0;
    background: linear-gradient(135deg, rgba(26, 26, 46, 0.98), rgba(22, 33, 62, 0.98));
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    flex-direction: column;
    padding: 16px 22px;
    display: none;
    box-shadow: 0 14px 30px rgba(0, 0, 0, 0.35);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    animation: navDrop 0.3s var(--ease);
  }

  [data-theme="dark"] nav.main-nav {
    background: linear-gradient(135deg, rgba(13, 13, 23, 0.98), rgba(18, 18, 42, 0.98));
  }

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

  nav.main-nav ul {
    flex-direction: column;
    gap: 14px;
  }

  .mobile-toggle {
    display: flex;
  }

  .search-box input {
    width: 96px;
  }

  @keyframes navDrop {
    from {
      opacity: 0;
      transform: translateY(-10px);
    }
    to {
      opacity: 1;
      transform: none;
    }
  }
}

/* ===== Responsive: 640px ===== */
@media (max-width: 640px) {
  .grid-3,
  .grid-4,
  .grid-2,
  .article-list {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    font-size: 25px;
  }

  .hero-stats {
    gap: 18px;
  }

  .hero-stats .stat strong {
    font-size: 22px;
  }

  .section-head h2 {
    font-size: 23px;
  }

  .footer-links {
    grid-template-columns: 1fr;
  }

  .search-box {
    display: none;
  }

  section {
    padding: 48px 0;
  }

  .card {
    padding: 22px;
  }

  .howto-steps li {
    padding: 16px 16px 16px 60px;
  }

  .howto-steps li::before {
    left: 14px;
    top: 16px;
    width: 30px;
    height: 30px;
    font-size: 14px;
  }

  .back-top {
    right: 16px;
    bottom: 18px;
    width: 42px;
    height: 42px;
  }
}

/* ===== 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;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ===== Print ===== */
@media print {
  header.site-header,
  .back-top,
  nav.main-nav,
  .header-tools {
    display: none !important;
  }

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

  .card,
  .article-item,
  .faq-item {
    box-shadow: none;
    border-color: #ccc;
  }
}