:root {
  --bg: #f6f8fc;
  --bg-soft: #eef2f9;
  --fg: #171b23;
  --fg-soft: #3d4553;
  --muted: #66707f;
  --line: rgba(23, 27, 35, 0.08);
  --brand: #1f6feb;
  --brand-2: #7a3cff;
  --brand-3: #e8590c;
  --accent: #0ea5a4;
  --card: rgba(255, 255, 255, 0.72);
  --card-solid: #ffffff;
  --glass: rgba(255, 255, 255, 0.55);
  --glass-border: rgba(255, 255, 255, 0.65);
  --shadow-sm: 0 2px 8px rgba(23, 27, 35, 0.06);
  --shadow-md: 0 10px 30px rgba(23, 27, 35, 0.08);
  --shadow-lg: 0 22px 60px rgba(23, 27, 35, 0.12);
  --radius: 16px;
  --radius-sm: 10px;
  --radius-pill: 999px;
  --grad-banner: linear-gradient(120deg, #1f6feb 0%, #7a3cff 48%, #e8590c 100%);
  --grad-brand: linear-gradient(135deg, #1f6feb, #7a3cff);
  --grad-soft: linear-gradient(180deg, rgba(31, 111, 235, 0.08), rgba(122, 60, 255, 0.04));
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

body.dark {
  --bg: #0b0f16;
  --bg-soft: #111722;
  --fg: #e8ecf3;
  --fg-soft: #c3cad6;
  --muted: #8d97a6;
  --line: rgba(232, 236, 243, 0.1);
  --brand: #5b9bff;
  --brand-2: #a077ff;
  --brand-3: #ff7a3d;
  --accent: #2dd4bf;
  --card: rgba(22, 29, 41, 0.72);
  --card-solid: #161d29;
  --glass: rgba(22, 29, 41, 0.55);
  --glass-border: rgba(232, 236, 243, 0.12);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 10px 30px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 22px 60px rgba(0, 0, 0, 0.55);
  --grad-banner: linear-gradient(120deg, #173a7a 0%, #3b1f7a 50%, #7a3410 100%);
  --grad-brand: linear-gradient(135deg, #5b9bff, #a077ff);
  --grad-soft: linear-gradient(180deg, rgba(91, 155, 255, 0.1), rgba(160, 119, 255, 0.05));
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.78;
  color: var(--fg);
  background: var(--bg);
  background-image:
    radial-gradient(900px 500px at 8% -10%, rgba(31, 111, 235, 0.12), transparent 60%),
    radial-gradient(800px 460px at 100% 0%, rgba(122, 60, 255, 0.1), transparent 55%),
    radial-gradient(700px 420px at 50% 100%, rgba(232, 89, 12, 0.06), transparent 60%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 0.35s var(--ease), color 0.35s var(--ease);
  overflow-x: hidden;
}

body.dark {
  background-image:
    radial-gradient(900px 500px at 8% -10%, rgba(91, 155, 255, 0.16), transparent 60%),
    radial-gradient(800px 460px at 100% 0%, rgba(160, 119, 255, 0.14), transparent 55%),
    radial-gradient(700px 420px at 50% 100%, rgba(255, 122, 61, 0.08), transparent 60%);
}

::selection {
  background: rgba(31, 111, 235, 0.22);
  color: var(--fg);
}

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

a:hover {
  color: var(--brand-2);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

h1, h2, h3, h4 {
  line-height: 1.35;
  letter-spacing: 0.01em;
  color: var(--fg);
}

h1 {
  font-size: clamp(1.7rem, 3.2vw, 2.4rem);
  margin: 0 0 14px;
  font-weight: 800;
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

p {
  margin: 0 0 14px;
  color: var(--fg-soft);
}

strong {
  color: var(--fg);
  font-weight: 700;
}

.container {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 22px;
}

/* ============ Header ============ */
header.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--glass);
  border-bottom: 1px solid var(--line);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  backdrop-filter: saturate(180%) blur(18px);
  transition: background 0.35s var(--ease), box-shadow 0.35s var(--ease);
}

header.site-header:hover {
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 12px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 19px;
  color: var(--fg);
  letter-spacing: 0.02em;
  flex-shrink: 0;
}

.brand:hover {
  text-decoration: none;
  color: var(--fg);
}

.brand .logo {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: var(--grad-brand);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 19px;
  font-weight: 800;
  box-shadow: 0 6px 18px rgba(31, 111, 235, 0.35);
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease);
}

.brand:hover .logo {
  transform: rotate(-6deg) scale(1.06);
  box-shadow: 0 10px 24px rgba(122, 60, 255, 0.4);
}

nav.main-nav {
  margin-left: auto;
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

nav.main-nav a {
  padding: 7px 12px;
  border-radius: var(--radius-pill);
  color: var(--fg-soft);
  font-size: 14.5px;
  font-weight: 500;
  position: relative;
  transition: color 0.25s var(--ease), background 0.25s var(--ease);
}

nav.main-nav a:hover {
  background: var(--grad-soft);
  color: var(--brand);
  text-decoration: none;
}

nav.main-nav a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 2px;
  width: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--grad-brand);
  transform: translateX(-50%);
  transition: width 0.3s var(--ease);
}

nav.main-nav a:hover::after {
  width: 55%;
}

.header-actions {
  display: flex;
  gap: 8px;
  align-items: center;
}

.btn {
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--fg);
  padding: 8px 15px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  font-size: 14px;
  font-family: inherit;
  font-weight: 500;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), background 0.25s var(--ease), color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: rgba(31, 111, 235, 0.35);
  color: var(--brand);
}

.btn:active {
  transform: translateY(0);
}

.btn.primary {
  background: var(--grad-brand);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 6px 18px rgba(31, 111, 235, 0.3);
}

.btn.primary:hover {
  color: #fff;
  box-shadow: 0 10px 26px rgba(122, 60, 255, 0.4);
}

.search-box {
  display: flex;
  gap: 6px;
}

.search-box input {
  padding: 8px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--card);
  color: var(--fg);
  font-size: 14px;
  font-family: inherit;
  width: 180px;
  outline: none;
  transition: width 0.35s var(--ease), border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.search-box input::placeholder {
  color: var(--muted);
}

.search-box input:focus {
  width: 220px;
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(31, 111, 235, 0.15);
}

.menu-toggle {
  display: none;
}

/* ============ Breadcrumb ============ */
.breadcrumb {
  font-size: 13.5px;
  color: var(--muted);
  padding: 16px 0 4px;
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

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

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

/* ============ Banner ============ */
.banner {
  position: relative;
  overflow: hidden;
  border-radius: 22px;
  margin: 20px 0 26px;
  background: var(--grad-banner);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
  isolation: isolate;
}

.banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(600px 300px at 15% 20%, rgba(255, 255, 255, 0.22), transparent 60%),
    radial-gradient(500px 280px at 85% 80%, rgba(255, 255, 255, 0.12), transparent 60%);
  pointer-events: none;
  z-index: 0;
}

.banner::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 36px 36px;
  opacity: 0.5;
  pointer-events: none;
  z-index: 0;
}

.slides {
  position: relative;
  height: 320px;
  z-index: 1;
}

.slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  visibility: hidden;
  transform: scale(1.02);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease), visibility 0.7s;
  display: flex;
  align-items: center;
  padding: 40px 44px;
  gap: 28px;
}

.slide.active {
  opacity: 1;
  visibility: visible;
  transform: scale(1);
}

.slide .slide-text {
  flex: 1;
  min-width: 0;
}

.slide h2 {
  margin: 0 0 12px;
  font-size: clamp(1.4rem, 2.6vw, 2rem);
  font-weight: 800;
  color: #fff;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.18);
  letter-spacing: 0.01em;
}

.slide p {
  margin: 0;
  color: rgba(255, 255, 255, 0.88);
  font-size: 15.5px;
  max-width: 560px;
  line-height: 1.7;
}

.slide .slide-art {
  width: 230px;
  height: 168px;
  border-radius: 16px;
  flex-shrink: 0;
  box-shadow: 0 18px 44px rgba(0, 0, 0, 0.28);
  transition: transform 0.6s var(--ease);
}

.slide.active .slide-art {
  animation: floaty 5s ease-in-out infinite;
}

@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

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

.banner-dots button {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: none;
  background: rgba(255, 255, 255, 0.45);
  cursor: pointer;
  padding: 0;
  transition: width 0.35s var(--ease), background 0.35s var(--ease), transform 0.25s var(--ease);
}

.banner-dots button:hover {
  background: rgba(255, 255, 255, 0.85);
  transform: scale(1.15);
}

.banner-dots button.active {
  width: 26px;
  border-radius: 6px;
  background: #fff;
}

/* ============ Anchor nav ============ */
.anchor-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 6px 0 8px;
}

.anchor-nav a {
  background: var(--card);
  border: 1px solid var(--line);
  padding: 7px 15px;
  border-radius: var(--radius-pill);
  font-size: 13.5px;
  color: var(--fg-soft);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  transition: transform 0.25s var(--ease), background 0.3s var(--ease), color 0.3s var(--ease), box-shadow 0.3s var(--ease), border-color 0.3s var(--ease);
}

.anchor-nav a:hover {
  background: var(--grad-brand);
  color: #fff;
  border-color: transparent;
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(31, 111, 235, 0.28);
}

/* ============ Sections ============ */
section {
  padding: 44px 0;
  border-bottom: 1px solid var(--line);
  position: relative;
}

section:last-of-type {
  border-bottom: none;
}

section h2 {
  font-size: clamp(1.4rem, 2.4vw, 1.75rem);
  margin: 0 0 10px;
  font-weight: 800;
  letter-spacing: 0.01em;
}

section h2 .accent {
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.lead {
  color: var(--muted);
  max-width: 840px;
  margin: 0 0 22px;
  font-size: 16.5px;
  line-height: 1.85;
}

h3 {
  font-size: 1.15rem;
  margin: 26px 0 10px;
  font-weight: 700;
  color: var(--fg);
  position: relative;
  padding-left: 14px;
}

h3::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.35em;
  bottom: 0.35em;
  width: 4px;
  border-radius: 3px;
  background: var(--grad-brand);
}

h4 {
  font-size: 16px;
  margin: 18px 0 8px;
  color: var(--brand);
  font-weight: 700;
}

/* ============ Grid & Cards ============ */
.grid {
  display: grid;
  gap: 20px;
}

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

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

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease), border-color 0.4s var(--ease);
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--grad-brand);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.45s var(--ease);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(31, 111, 235, 0.25);
}

.card:hover::before {
  transform: scaleX(1);
}

.card h3 {
  margin-top: 0;
  padding-left: 0;
  font-size: 17px;
}

.card h3::before {
  display: none;
}

.card p {
  margin-bottom: 0;
  font-size: 14.5px;
  color: var(--muted);
}

.card .meta {
  font-size: 13px;
  color: var(--muted);
  margin: 0 0 8px;
}

/* ============ Stats ============ */
.stat-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  text-align: center;
  margin-top: 8px;
}

.stat {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px 12px;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease);
}

.stat:hover {
  transform: translateY(-5px) scale(1.02);
  box-shadow: var(--shadow-md);
}

.stat .num {
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  font-weight: 800;
  line-height: 1.2;
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.stat .label {
  color: var(--muted);
  font-size: 13.5px;
  margin-top: 4px;
}

/* ============ Article cards ============ */
.article-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  display: flex;
  flex-direction: column;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease), border-color 0.4s var(--ease);
}

.article-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(122, 60, 255, 0.25);
}

.article-card h3 {
  font-size: 16.5px;
  margin: 0 0 6px;
  padding-left: 0;
  transition: color 0.3s var(--ease);
}

.article-card h3::before {
  display: none;
}

.article-card:hover h3 {
  color: var(--brand);
}

.article-card .meta {
  color: var(--muted);
  font-size: 12.5px;
  margin-bottom: 10px;
}

.article-card .summary {
  color: var(--muted);
  font-size: 14px;
  flex: 1;
  margin-bottom: 0;
}

.article-card .more {
  margin-top: 12px;
  font-size: 14px;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: gap 0.3s var(--ease), color 0.3s var(--ease);
}

.article-card .more::after {
  content: "→";
  transition: transform 0.3s var(--ease);
}

.article-card:hover .more::after {
  transform: translateX(4px);
}

/* ============ FAQ ============ */
.faq-item {
  border: 1px solid var(--line);
  border-radius: 12px;
  margin-bottom: 12px;
  background: var(--card);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  overflow: hidden;
  transition: box-shadow 0.35s var(--ease), border-color 0.35s var(--ease), transform 0.35s var(--ease);
}

.faq-item:hover {
  border-color: rgba(31, 111, 235, 0.3);
  box-shadow: var(--shadow-md);
}

.faq-item.open {
  border-color: rgba(31, 111, 235, 0.35);
  box-shadow: var(--shadow-md);
}

.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 16px 20px;
  font-size: 15.5px;
  font-weight: 600;
  color: var(--fg);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  font-family: inherit;
  transition: color 0.3s var(--ease), background 0.3s var(--ease);
}

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

.faq-q span {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--grad-soft);
  color: var(--brand);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 700;
  line-height: 1;
  transition: transform 0.35s var(--ease), background 0.35s var(--ease), color 0.35s var(--ease);
}

.faq-item.open .faq-q span {
  transform: rotate(45deg);
  background: var(--grad-brand);
  color: #fff;
}

.faq-a {
  display: none;
  padding: 0 20px 18px;
  color: var(--muted);
  font-size: 14.5px;
  line-height: 1.8;
  animation: fadeDown 0.4s var(--ease);
}

.faq-item.open .faq-a {
  display: block;
}

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

/* ============ Steps ============ */
ol.steps {
  padding-left: 0;
  list-style: none;
  counter-reset: step;
  margin: 0 0 8px;
}

ol.steps li {
  position: relative;
  margin-bottom: 12px;
  padding: 14px 18px 14px 58px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  counter-increment: step;
  font-size: 15px;
  color: var(--fg-soft);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease), border-color 0.35s var(--ease);
}

ol.steps li::before {
  content: counter(step);
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--grad-brand);
  color: #fff;
  font-size: 14px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(31, 111, 235, 0.3);
}

ol.steps li:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(31, 111, 235, 0.28);
}

ol.steps li strong {
  color: var(--brand);
}

/* ============ Tags ============ */
.tag {
  display: inline-block;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  padding: 4px 12px;
  font-size: 13px;
  color: var(--muted);
  margin: 0 8px 8px 0;
  transition: transform 0.25s var(--ease), background 0.3s var(--ease), color 0.3s var(--ease), border-color 0.3s var(--ease);
}

.tag:hover {
  transform: translateY(-2px);
  background: var(--grad-soft);
  color: var(--brand);
  border-color: rgba(31, 111, 235, 0.3);
}

/* ============ Author box ============ */
.author-box {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.35s var(--ease), transform 0.35s var(--ease);
}

.author-box:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.author-box .avatar {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  flex-shrink: 0;
  box-shadow: 0 6px 18px rgba(31, 111, 235, 0.3);
}

.author-box p {
  margin: 0 0 6px;
  font-size: 14.5px;
}

.author-box > div > p:last-child {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
}

/* ============ Contact grid ============ */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

/* ============ Footer ============ */
.footer {
  background: var(--card);
  border-top: 1px solid var(--line);
  padding: 44px 0 22px;
  font-size: 14px;
  color: var(--muted);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  margin-top: 8px;
}

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

.footer h4 {
  color: var(--fg);
  margin: 0 0 12px;
  font-size: 15px;
  font-weight: 700;
}

.footer p {
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.75;
  margin: 0 0 8px;
}

.footer a {
  color: var(--muted);
  display: block;
  margin-bottom: 7px;
  font-size: 13.5px;
  width: fit-content;
  transition: color 0.25s var(--ease), transform 0.25s var(--ease);
}

.footer a:hover {
  color: var(--brand);
  transform: translateX(3px);
  text-decoration: none;
}

.footer-bottom {
  border-top: 1px solid var(--line);
  margin-top: 28px;
  padding-top: 18px;
  font-size: 12.5px;
  text-align: center;
  color: var(--muted);
}

.footer-bottom p {
  margin: 0 0 6px;
  font-size: 12.5px;
}

/* ============ Back top ============ */
.back-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--grad-brand);
  color: #fff;
  border: none;
  cursor: pointer;
  font-size: 18px;
  display: none;
  z-index: 200;
  box-shadow: 0 10px 26px rgba(31, 111, 235, 0.4);
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease), opacity 0.3s var(--ease);
}

.back-top.show {
  display: block;
  animation: popIn 0.35s var(--ease);
}

.back-top:hover {
  transform: translateY(-4px) scale(1.06);
  box-shadow: 0 16px 34px rgba(122, 60, 255, 0.5);
}

@keyframes popIn {
  from { opacity: 0; transform: scale(0.6); }
  to { opacity: 1; transform: scale(1); }
}

/* ============ 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;
}

/* ============ Focus visible ============ */
a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
  border-radius: 6px;
}

/* ============ Responsive ============ */
@media (max-width: 1024px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .slide .slide-art {
    width: 190px;
    height: 140px;
  }
}

@media (max-width: 900px) {
  .grid-2,
  .stat-row,
  .contact-grid {
    grid-template-columns: 1fr 1fr;
  }
  .header-inner {
    gap: 12px;
  }
  nav.main-nav {
    order: 3;
    width: 100%;
    margin-left: 0;
    justify-content: flex-start;
  }
  .search-box input {
    width: 150px;
  }
  .search-box input:focus {
    width: 180px;
  }
  .slides {
    height: 340px;
  }
  .slide {
    padding: 32px;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 15px;
  }
  .container {
    padding: 0 16px;
  }
  .header-inner {
    flex-wrap: wrap;
    padding: 10px 0;
  }
  nav.main-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--glass);
    -webkit-backdrop-filter: saturate(180%) blur(18px);
    backdrop-filter: saturate(180%) blur(18px);
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    padding: 12px 16px;
    gap: 4px;
    box-shadow: var(--shadow-md);
  }
  nav.main-nav.open {
    display: flex;
    animation: fadeDown 0.35s var(--ease);
  }
  nav.main-nav a {
    width: 100%;
    padding: 10px 14px;
    border-radius: 10px;
  }
  nav.main-nav a::after {
    display: none;
  }
  .menu-toggle {
    display: inline-block;
  }
  .header-actions {
    margin-left: auto;
  }
  .search-box {
    display: none;
  }
  .slides {
    height: 420px;
  }
  .slide {
    flex-direction: column;
    padding: 28px 22px 44px;
    text-align: center;
    justify-content: center;
    gap: 18px;
  }
  .slide p {
    font-size: 14.5px;
  }
  .slide .slide-art {
    width: 100%;
    max-width: 260px;
    height: 130px;
  }
  .grid-3,
  .grid-2,
  .stat-row,
  .footer-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }
  .stat-row {
    grid-template-columns: 1fr 1fr;
  }
  .author-box {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
  section {
    padding: 34px 0;
  }
  h1 {
    font-size: 1.55rem;
  }
  .faq-q {
    padding: 14px 16px;
    font-size: 14.5px;
  }
  .faq-a {
    padding: 0 16px 16px;
  }
  ol.steps li {
    padding: 12px 14px 12px 52px;
  }
  .back-top {
    right: 16px;
    bottom: 16px;
    width: 42px;
    height: 42px;
  }
}

@media (max-width: 380px) {
  .stat-row {
    grid-template-columns: 1fr;
  }
  .slide h2 {
    font-size: 1.2rem;
  }
}

/* ============ 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,
  .banner,
  .back-top,
  .anchor-nav,
  .footer {
    display: none !important;
  }
  body {
    background: #fff;
    color: #000;
  }
  .card,
  .article-card,
  .faq-item {
    box-shadow: none;
    border-color: #ccc;
  }
}