:root {
  --ink: #0b1220;
  --muted: #5b6577;
  --line: rgba(15, 23, 42, 0.08);
  --soft: #f4f6f9;
  --btn: #1d4ed8;
  --shell: 1400px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}
html { scroll-behavior: smooth; }
body {
  font-family: "Instrument Sans", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
}
.shell { max-width: var(--shell); margin: 0 auto; padding: 0 24px; }

.hero {
  position: relative;
  padding: clamp(48px, 8vw, 88px) 0 0;
  text-align: center;
  overflow: visible;
}
.hero::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 8%;
  width: min(560px, 80vw);
  height: 220px;
  transform: translateX(-50%);
  background:
    radial-gradient(ellipse at 50% 40%, rgba(37, 99, 235, 0.16), transparent 68%),
    radial-gradient(ellipse at 70% 60%, rgba(14, 165, 233, 0.10), transparent 60%);
  pointer-events: none;
  z-index: 0;
  filter: blur(2px);
  animation: aura 6s ease-in-out infinite alternate;
}
.hero-copy {
  position: relative;
  z-index: 1;
  max-width: 42rem;
  margin: 0 auto;
  padding: 0 8px;
  animation: rise 0.8s var(--ease) both;
}
.hero h1 {
  margin: 0;
  font-size: clamp(2.15rem, 5vw, 3.55rem);
  line-height: 1.12;
  letter-spacing: -0.048em;
  font-weight: 700;
  color: var(--ink);
}
.hero h1 .brand-grad,
.hero h1 .grad,
.dl-hero h1 .brand-grad,
.dl-hero h1 .grad {
  display: inline-block;
  background: linear-gradient(105deg, #0f172a 0%, #1d4ed8 28%, #0ea5e9 52%, #2563eb 72%, #0f172a 100%);
  background-size: 220% 100%;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  animation: sheen 5.5s ease-in-out infinite;
}
.hero .lead {
  margin: 18px auto 0;
  max-width: 36rem;
  color: var(--muted);
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  line-height: 1.7;
}
.hero .lead .mark {
  color: #1e40af;
  font-weight: 550;
  background: linear-gradient(180deg, transparent 62%, rgba(37, 99, 235, 0.14) 62%);
  border-radius: 2px;
  padding: 0 1px;
}
a.cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 48px;
  padding: 0 30px;
  border-radius: 980px;
  background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 55%, #0ea5e9 140%);
  background-size: 140% 140%;
  color: #fff;
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
  box-shadow: 0 10px 28px -12px rgba(37, 99, 235, 0.55);
  transition: background-position .35s var(--ease), transform .2s var(--ease), box-shadow .2s;
}
a.cta:hover {
  color: #fff;
  background-position: 100% 50%;
  transform: translateY(-1px);
}
a.cta.ghost {
  background: #fff;
  color: var(--ink);
  border: 1px solid var(--line);
  box-shadow: none;
}
a.cta.ghost:hover { color: var(--ink); }
.hero .cta { margin-top: 28px; animation: rise 0.85s var(--ease) 0.08s both; }
.hero-visual {
  margin: clamp(40px, 6vw, 64px) auto 0;
  max-width: 960px;
  padding: 0 16px;
  animation: float-in 1s var(--ease) 0.12s both;
}
.hero-visual img { width: 100%; height: auto; display: block; background: transparent; }
.hero-visual-floating {
  max-width: 820px;
  margin-bottom: -120px;
  position: relative;
  z-index: 2;
}
.hero-visual-floating img {
  filter: drop-shadow(0 32px 64px rgba(29, 78, 216, 0.22));
  animation: hero-float 4.8s ease-in-out infinite;
  border-radius: 12px;
}

.features { margin-top: clamp(48px, 8vw, 96px); border-top: 1px solid var(--line); }
.chapter {
  padding: clamp(56px, 9vw, 104px) 0;
  border-bottom: 1px solid var(--line);
}
.chapter:nth-child(even) { background: linear-gradient(180deg, var(--soft) 0%, #fff 100%); }
.chapter-grid {
  display: grid;
  gap: clamp(28px, 4vw, 56px);
  align-items: start;
}
@media (min-width: 900px) {
  .chapter-grid { grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr); gap: 64px; }
  .chapter.reverse .chapter-grid { grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr); }
  .chapter.reverse .media { order: 2; }
  .chapter.reverse .copy { order: 1; }
  .media { position: sticky; top: 88px; }
}
.media {
  position: relative;
  aspect-ratio: 4 / 3;
  border-radius: 20px;
  overflow: hidden;
  background: radial-gradient(ellipse at 50% 45%, #1a2744 0%, #0b1220 68%, #070b14 100%);
  box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.08);
}
.media-floating {
  overflow: visible;
  background: none;
  box-shadow: none;
}
.media-floating img {
  filter: drop-shadow(0 24px 48px rgba(29, 78, 216, 0.2));
  animation: hero-float 4.8s ease-in-out infinite;
  border-radius: 12px;
}
.media img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  padding: 12px;
}
.chapter .copy { max-width: 38rem; }
@media (min-width: 900px) {
  .chapter:not(.reverse) .copy { padding-right: 4px; max-width: none; }
  .chapter.reverse .copy { padding-left: 4px; max-width: none; }
}
.no {
  display: inline-block;
  font-size: 12px;
  font-weight: 650;
  letter-spacing: 0.16em;
  color: #94a3b8;
  margin-bottom: 14px;
}
.chapter h2 {
  margin: 0;
  font-size: clamp(1.45rem, 2.4vw, 1.9rem);
  line-height: 1.25;
  letter-spacing: -0.035em;
  font-weight: 700;
  color: var(--ink);
}
.chapter .body {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 1.02rem;
  line-height: 1.8;
}
.points { margin: 20px 0 0; padding: 0; list-style: none; display: grid; gap: 12px; }
.points li {
  position: relative;
  padding-left: 18px;
  font-size: 0.95rem;
  line-height: 1.7;
  color: #3f4b5f;
}
.points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.65em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #94a3b8;
  transition: background 0.45s var(--ease), box-shadow 0.45s var(--ease), transform 0.45s var(--ease);
}

/* Feature text reveal (A) + point-by-point light-up (C) */
.chapter .copy .no,
.chapter .copy h2,
.chapter .copy .body,
.chapter .copy .points li {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity 0.55s var(--ease),
    transform 0.55s var(--ease),
    color 0.45s var(--ease);
}
.chapter .copy .no { transition-delay: 0s; }
.chapter .copy h2 { transition-delay: 0.08s; }
.chapter .copy .body { transition-delay: 0.16s; }
.chapter .copy .points li:nth-child(1) { transition-delay: 0.28s; }
.chapter .copy .points li:nth-child(2) { transition-delay: 0.4s; }
.chapter .copy .points li:nth-child(3) { transition-delay: 0.52s; }
.chapter .copy .points li:nth-child(4) { transition-delay: 0.64s; }

.chapter.is-in .copy .no,
.chapter.is-in .copy h2,
.chapter.is-in .copy .body,
.chapter.is-in .copy .points li {
  opacity: 1;
  transform: translateY(0);
}
.chapter.is-in .copy .points li {
  color: #1e293b;
}
.chapter.is-in .copy .points li::before {
  background: var(--btn);
  box-shadow: 0 0 0 4px rgba(29, 78, 216, 0.14);
  transform: scale(1.15);
}

.foot-cta {
  text-align: center;
  padding: clamp(72px, 12vw, 120px) 24px;
  background: radial-gradient(700px 280px at 50% 0%, #e8eef8 0%, transparent 70%);
}
.foot-cta h2 {
  margin: 0;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  letter-spacing: -0.04em;
  font-weight: 700;
  color: var(--ink);
}
.foot-cta p { margin: 12px auto 28px; max-width: 28rem; color: var(--muted); font-size: 1.02rem; line-height: 1.65; }

/* Download */
.dl-hero {
  min-height: calc(100svh - 72px);
  display: flex;
  align-items: center;
  padding: clamp(40px, 6vh, 88px) 0 clamp(48px, 7vh, 96px);
  text-align: center;
  background:
    radial-gradient(900px 320px at 50% 0%, rgba(59, 130, 246, 0.1) 0%, transparent 70%),
    linear-gradient(180deg, #eef4ff 0%, #f7f9fc 48%, #fff 100%);
  box-sizing: border-box;
}
.dl-hero .shell {
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.dl-hero h1 {
  margin: 0 auto;
  max-width: 16em;
  font-size: clamp(1.85rem, 4.2vw, 2.9rem);
  letter-spacing: -0.04em;
  line-height: 1.28;
  color: var(--ink);
  animation: float-in 0.9s var(--ease) both;
}
.dl-hero h1 .brand-grad {
  animation: sheen 5.5s ease-in-out infinite, dl-title-pop 0.85s var(--ease) 0.08s both;
}
.dl-hero h1 .grad {
  animation: sheen 5.5s ease-in-out 0.35s infinite, dl-title-pop 0.85s var(--ease) 0.18s both;
}
.dl-hero .lead {
  margin: clamp(18px, 3.2vh, 28px) auto 0;
  max-width: 42rem;
  color: var(--muted);
  font-size: clamp(1.02rem, 1.7vw, 1.14rem);
  line-height: 1.8;
  animation: rise 0.9s var(--ease) 0.16s both;
}
@keyframes dl-title-pop {
  from { opacity: 0; transform: translateY(14px) scale(0.98); filter: blur(4px); }
  to { opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
}
.dl-grid {
  display: grid;
  gap: 20px;
  margin: clamp(40px, 8vh, 80px) 0 0;
  text-align: left;
}
@media (min-width: 900px) {
  .dl-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 28px; }
}
.dl-card {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: clamp(32px, 4vh, 44px) 24px clamp(28px, 3.5vh, 36px);
  border: 1px solid rgba(148, 163, 184, 0.28);
  border-radius: 18px;
  background: #fff;
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.05);
  transition: border-color 0.25s var(--ease), box-shadow 0.25s var(--ease), transform 0.25s var(--ease);
}
@media (max-width: 899px) {
  .dl-hero {
    min-height: 0;
    align-items: flex-start;
  }
}
.dl-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 34px rgba(15, 23, 42, 0.08);
}
.dl-card.is-current {
  border-color: #3b82f6;
  box-shadow: 0 14px 36px rgba(37, 99, 235, 0.14);
}
.dl-badge {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 5px 12px;
  border-radius: 999px;
  background: #3b82f6;
  color: #fff;
  font-size: 12px;
  font-weight: 650;
  letter-spacing: 0.02em;
  white-space: nowrap;
  box-shadow: 0 6px 14px rgba(37, 99, 235, 0.28);
}
.dl-badge[hidden] { display: none; }
.dl-icon {
  width: 64px;
  height: 64px;
  margin-bottom: 18px;
  position: relative;
}
.dl-icon img {
  display: block;
  width: 64px;
  height: 64px;
}
.dl-icon .dl-icon-active { display: none; }
.dl-card.is-current .dl-icon .dl-icon-idle { display: none; }
.dl-card.is-current .dl-icon .dl-icon-active { display: block; }
.dl-card.is-current[data-platform="win"] .dl-icon img {
  filter: brightness(0) saturate(100%) invert(42%) sepia(98%) saturate(2476%) hue-rotate(210deg) brightness(101%) contrast(101%);
}
.dl-card h2 {
  margin: 0;
  font-size: 1.2rem;
  letter-spacing: -0.02em;
  color: var(--ink);
}
.dl-req {
  margin: 12px 0 0;
  min-height: 3.2em;
  color: #64748b;
  font-size: 0.9rem;
  line-height: 1.65;
}
.dl-btn {
  margin-top: 24px;
  width: 100%;
  max-width: 220px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  border: 1px solid #dbe3ef;
  border-radius: 10px;
  text-decoration: none;
  color: #64748b;
  background: #fff;
  font-size: 15px;
  font-weight: 650;
  transition: background 0.25s var(--ease), border-color 0.25s var(--ease), color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}
.dl-card.is-current .dl-btn {
  color: #fff;
  background: #3b82f6;
  border-color: #3b82f6;
  box-shadow: 0 10px 22px rgba(37, 99, 235, 0.28);
}
.dl-card:not(.is-current) .dl-btn:hover {
  border-color: #93c5fd;
  color: #1d4ed8;
}

.dl-scenes {
  padding: 56px 24px 24px;
  border-top: 1px solid var(--line);
}
.dl-scenes-head {
  text-align: center;
  max-width: 38rem;
  margin: 0 auto 28px;
}
.dl-scenes-head h2 {
  margin: 0;
  font-size: clamp(1.45rem, 2.6vw, 1.9rem);
  letter-spacing: -0.03em;
  color: var(--ink);
}
.dl-scenes-head p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.75;
}
.dl-scene-grid {
  display: grid;
  gap: 16px;
}
@media (min-width: 800px) {
  .dl-scene-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
}
.dl-scene {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 24px 22px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: linear-gradient(180deg, #fff 0%, #f8fafc 100%);
  transition: border-color 0.25s var(--ease), box-shadow 0.25s var(--ease), transform 0.25s var(--ease);
}
.dl-scene:hover {
  border-color: #93c5fd;
  box-shadow: 0 14px 32px rgba(29, 78, 216, 0.08);
  transform: translateY(-2px);
}
.dl-scene-tag {
  margin: 0;
  display: inline-flex;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(29, 78, 216, 0.08);
  color: var(--btn);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.dl-scene h3 {
  margin: 14px 0 0;
  font-size: 1.12rem;
  letter-spacing: -0.02em;
  color: var(--ink);
  line-height: 1.4;
}
.dl-scene p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.96rem;
  line-height: 1.75;
}
.dl-scene-link {
  margin-top: auto;
  padding-top: 18px;
  color: var(--btn);
  font-size: 0.95rem;
  font-weight: 650;
  text-decoration: none;
}
.dl-scene-link:hover { text-decoration: underline; }
.dl-scenes-note {
  margin: 24px auto 0;
  max-width: 40rem;
  text-align: center;
  color: #64748b;
  font-size: 0.92rem;
  line-height: 1.75;
}
.dl-scenes-note a {
  color: var(--btn);
  text-decoration: none;
  font-weight: 600;
}
.dl-scenes-note a:hover { text-decoration: underline; }

.os-row { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin: 32px 0 0; }
.os-chip {
  appearance: none; border: 1px solid var(--line); background: #fff; color: var(--ink);
  display: inline-flex; align-items: center; height: 42px; padding: 0 16px;
  border-radius: 999px; font-size: 14px; font-weight: 600; cursor: pointer;
  font-family: inherit;
}
.os-chip:hover { border-color: #93c5fd; color: var(--btn); }
.os-chip[aria-selected="true"] {
  background: var(--ink); color: #fff; border-color: var(--ink);
}
.stage { margin: 36px 0 8px; overflow: hidden; border-top: 1px solid var(--line); }
.track { display: flex; width: 500%; transition: transform .55s var(--ease); }
.track.track-2 { width: 200%; }
.track.track-2 .plat { width: 50%; flex: 0 0 50%; }
.plat {
  width: 20%;
  flex: 0 0 20%;
  display: grid;
  gap: 28px;
  align-items: start;
  padding: 40px 2px 8px;
}
@media (min-width: 860px) {
  .plat { grid-template-columns: 1.05fr 0.95fr; gap: 48px; }
}
.shot {
  border-radius: 18px;
  overflow: hidden;
  background: var(--soft);
  aspect-ratio: 16 / 10;
}
.shot img { width: 100%; height: 100%; object-fit: cover; display: block; }
.plat h2 { margin: 0 0 10px; font-size: 1.45rem; letter-spacing: -0.03em; text-align: center; color: var(--ink); }
.plat p { margin: 0; color: var(--muted); line-height: 1.75; }
.actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin: 16px 0 8px; }
.actions .cta { height: 46px; padding: 0 22px; font-size: 14px; }
.sys { margin: 0 0 6px; font-size: 13px; color: #8b95a5; text-align: center; }
.sys + .body { margin-top: 12px; }
.plat .body { margin: 0 0 12px; font-size: 0.98rem; }
.facts { margin: 16px 0 0; padding: 0; list-style: none; display: grid; gap: 12px; }
.facts li { color: #3f4b5f; font-size: 0.92rem; line-height: 1.6; }
.facts strong { display: block; color: var(--ink); font-size: 0.95rem; margin-bottom: 2px; }
.plat[aria-hidden="true"] { pointer-events: none; }
.faq { padding: 56px 0 88px; border-top: 1px solid var(--line); }
.faq-head { text-align: center; margin: 0 auto 28px; max-width: 36rem; }
.faq-head h2 { margin: 0; font-size: clamp(1.45rem, 2.6vw, 1.85rem); letter-spacing: -0.03em; color: var(--ink); }
.faq-head p { margin: 12px 0 0; color: var(--muted); line-height: 1.7; }
.faq-list { max-width: 40rem; margin: 0 auto; }
.faq-list details { border-bottom: 1px solid var(--line); padding: 16px 0; }
.faq-list summary {
  cursor: pointer;
  font-weight: 650;
  font-size: 1rem;
  list-style: none;
  color: var(--ink);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after {
  content: "+";
  flex-shrink: 0;
  font-size: 1.25rem;
  font-weight: 500;
  line-height: 1;
  color: #94a3b8;
}
.faq-list details[open] summary::after { content: "–"; }
.faq-list details p { margin: 10px 0 0; color: var(--muted); line-height: 1.75; font-size: 0.95rem; }

.pay-methods {
  text-align: center;
  padding: 48px 24px 40px;
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg, #f8fafc 0%, #fff 72%);
}
.pay-methods h2 {
  margin: 0 0 28px;
  font-size: clamp(1.45rem, 2.6vw, 1.85rem);
  letter-spacing: -0.03em;
  font-weight: 700;
  color: var(--ink);
}
.pay-logos {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 20px 28px;
}
.pay-logos li {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
}
.pay-logos img {
  display: block;
  height: 36px;
  width: auto;
  max-width: 140px;
  object-fit: contain;
}
@media (min-width: 900px) {
  .pay-logos { gap: 22px 36px; }
  .pay-logos img { height: 40px; }
}

.price-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 18px;
  margin: 18px 0 0;
  font-size: 0.92rem;
}
.price-links a {
  color: var(--btn);
  text-decoration: none;
  font-weight: 600;
}
.price-links a:hover { text-decoration: underline; }

.price-hero {
  padding: clamp(48px, 8vw, 80px) 0 28px;
  text-align: center;
}
.price-hero h1 {
  margin: 0 auto;
}
.price-hero .lead {
  margin-left: auto;
  margin-right: auto;
}

.price-intro {
  padding: 8px 24px 48px;
}
.price-intro > h2 {
  margin: 0 0 20px;
  text-align: center;
  font-size: clamp(1.35rem, 2.4vw, 1.7rem);
  letter-spacing: -0.03em;
  color: var(--ink);
}
.price-intro-grid {
  display: grid;
  gap: 16px;
}
@media (min-width: 800px) {
  .price-intro-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px; }
}
.price-intro-grid article {
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
}
.price-intro-grid h3 {
  margin: 0;
  font-size: 1.02rem;
  color: var(--ink);
}
.price-intro-grid p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* About */
.about-hero .lead { max-width: 40rem; }
.about-block {
  padding: clamp(48px, 7vw, 80px) 24px;
}
.about-block-soft {
  background: linear-gradient(180deg, #f8fafc 0%, #fff 100%);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding-left: 0;
  padding-right: 0;
}
.about-block-head {
  text-align: center;
  max-width: 40rem;
  margin: 0 auto 28px;
}
.about-block-head h2 {
  margin: 0;
  font-size: clamp(1.45rem, 2.6vw, 1.9rem);
  letter-spacing: -0.03em;
  color: var(--ink);
}
.about-block-head p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.75;
}
.about-prose {
  max-width: 46rem;
  margin: 0 auto;
}
.about-prose p {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 1.02rem;
  line-height: 1.85;
}
.about-timeline {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  max-width: 46rem;
  display: grid;
  gap: 18px;
}
.about-timeline li {
  position: relative;
  padding: 22px 22px 22px 24px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
}
.about-time {
  display: inline-flex;
  margin: 0 0 8px;
  padding: 3px 10px;
  border-radius: 999px;
  background: rgba(29, 78, 216, 0.08);
  color: var(--btn);
  font-size: 12px;
  font-weight: 700;
}
.about-timeline h3,
.about-version h3,
.about-problem-grid h3,
.about-service-grid h3 {
  margin: 0;
  font-size: 1.08rem;
  letter-spacing: -0.02em;
  color: var(--ink);
}
.about-timeline p,
.about-version p,
.about-problem-grid p,
.about-service-grid p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.96rem;
  line-height: 1.75;
}
.about-version-grid,
.about-problem-grid,
.about-service-grid {
  display: grid;
  gap: 16px;
}
@media (min-width: 800px) {
  .about-version-grid,
  .about-problem-grid,
  .about-service-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }
}
.about-version,
.about-problem-grid article,
.about-service-grid article {
  padding: 22px 20px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
}
.about-version-tag {
  margin: 0 0 10px;
  display: inline-flex;
  padding: 3px 10px;
  border-radius: 999px;
  background: #eff6ff;
  color: var(--btn);
  font-size: 12px;
  font-weight: 700;
}

.compare {
  padding: 24px 24px 56px;
  border-top: 1px solid var(--line);
}
.compare-head {
  text-align: center;
  max-width: 36rem;
  margin: 0 auto 24px;
}
.compare-head h2 {
  margin: 0;
  font-size: clamp(1.45rem, 2.6vw, 1.85rem);
  letter-spacing: -0.03em;
  color: var(--ink);
}
.compare-head p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.7;
}
.compare-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
}
.compare-table {
  width: 100%;
  min-width: 640px;
  border-collapse: collapse;
  font-size: 0.94rem;
}
.compare-table th,
.compare-table td {
  padding: 14px 16px;
  text-align: center;
  border-bottom: 1px solid var(--line);
  color: #3f4b5f;
  transition: background 0.25s var(--ease);
}
.compare-table thead th {
  background: #f8fafc;
  font-weight: 650;
  color: var(--ink);
}
.compare-table tbody th {
  text-align: left;
  font-weight: 600;
  color: var(--ink);
  background: #fff;
}
.compare-table tbody tr:last-child th,
.compare-table tbody tr:last-child td {
  border-bottom: none;
}
.compare-table tbody tr:hover th,
.compare-table tbody tr:hover td {
  background: #f8fbff;
}
.compare-table .col-hot {
  background: rgba(29, 78, 216, 0.04);
}
.compare-table thead .col-hot {
  background: rgba(29, 78, 216, 0.08);
  color: var(--btn);
}
.compare-table tbody tr:hover .col-hot {
  background: rgba(29, 78, 216, 0.1);
}
.hot-tag {
  display: inline-block;
  margin-left: 6px;
  padding: 2px 7px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: #fff;
  background: var(--btn);
  vertical-align: middle;
}
.mark-yes {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 700;
  line-height: 1;
  color: #fff;
  background: linear-gradient(145deg, #3b82f6 0%, #1d4ed8 100%);
  box-shadow: 0 6px 14px rgba(29, 78, 216, 0.28);
  transform: scale(0.92);
  opacity: 0.92;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), opacity 0.25s var(--ease);
}
.compare-table tbody tr:hover .mark-yes,
.compare.is-in .mark-yes {
  transform: scale(1);
  opacity: 1;
}
.compare.is-in .mark-yes {
  animation: mark-pop 0.45s var(--ease) both;
}
.compare.is-in tr:nth-child(4) .mark-yes { animation-delay: 0.04s; }
.compare.is-in tr:nth-child(5) .mark-yes { animation-delay: 0.1s; }
.compare.is-in tr:nth-child(6) .mark-yes { animation-delay: 0.16s; }
.compare.is-in tr:nth-child(7) .mark-yes { animation-delay: 0.22s; }
.compare.is-in tr:nth-child(8) .mark-yes { animation-delay: 0.28s; }
.mark-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 999px;
  font-size: 0.95rem;
  color: #94a3b8;
  background: #f1f5f9;
}
@keyframes mark-pop {
  from { opacity: 0; transform: scale(0.6); }
  to { opacity: 1; transform: scale(1); }
}
@media (prefers-reduced-motion: reduce) {
  .compare.is-in .mark-yes { animation: none; }
  .mark-yes { transform: none; opacity: 1; }
}

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

@keyframes rise {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes float-in {
  from { opacity: 0; transform: translateY(28px) scale(0.985); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}
@keyframes sheen {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}
@keyframes aura {
  from { opacity: 0.75; transform: translateX(-50%) scale(1); }
  to { opacity: 1; transform: translateX(-50%) scale(1.06); }
}
@keyframes hero-float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-14px); }
}
/* 404 */
.not-found {
  min-height: calc(100vh - 180px);
  display: flex;
  flex-direction: column;
}
.not-found-hero {
  position: relative;
  padding: clamp(72px, 12vw, 120px) 24px 40px;
  text-align: center;
  overflow: hidden;
}
.not-found-hero::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 12%;
  width: min(520px, 78vw);
  height: 200px;
  transform: translateX(-50%);
  background:
    radial-gradient(ellipse at 50% 40%, rgba(37, 99, 235, 0.14), transparent 68%),
    radial-gradient(ellipse at 70% 60%, rgba(14, 165, 233, 0.08), transparent 60%);
  pointer-events: none;
  z-index: 0;
  filter: blur(2px);
}
.not-found-code {
  position: relative;
  z-index: 1;
  margin: 0;
  font-size: clamp(4.5rem, 14vw, 7.5rem);
  line-height: 0.9;
  letter-spacing: -0.06em;
  font-weight: 700;
  background: linear-gradient(105deg, #0f172a 0%, #1d4ed8 35%, #0ea5e9 55%, #2563eb 75%, #0f172a 100%);
  background-size: 220% 100%;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  animation: sheen 5.5s ease-in-out infinite;
}
.not-found-hero h1 {
  position: relative;
  z-index: 1;
  margin: 18px 0 0;
  font-size: clamp(1.75rem, 3.5vw, 2.35rem);
  letter-spacing: -0.035em;
  color: var(--ink);
  font-weight: 700;
}
.not-found-hero .lead {
  position: relative;
  z-index: 1;
  margin: 14px auto 0;
  max-width: 28rem;
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.7;
}
.not-found-actions {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 28px;
}
.not-found-links {
  padding: 24px 24px clamp(64px, 8vw, 96px);
  max-width: 720px;
}
.not-found-links h2 {
  margin: 0 0 16px;
  text-align: center;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: #94a3b8;
}
.not-found-links ul {
  list-style: none;
  margin: 0;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 16px;
  overflow: hidden;
  background: #fff;
}
.not-found-links li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px 16px;
  padding: 14px 18px;
  border-top: 1px solid var(--line);
}
.not-found-links li:first-child {
  border-top: 0;
}
.not-found-links a {
  font-weight: 600;
  color: #1d4ed8;
  text-decoration: none;
}
.not-found-links a:hover {
  color: #1e40af;
}
.not-found-links span {
  color: var(--muted);
  font-size: 0.9rem;
}

/* Legal pages */
.legal-updated {
  margin: 18px auto 0;
  color: #94a3b8;
  font-size: 0.875rem;
}
.legal-doc .about-prose {
  max-width: 46rem;
}
.legal-doc h2 {
  margin: 32px 0 12px;
  font-size: 1.2rem;
  letter-spacing: -0.02em;
  color: var(--ink);
  font-weight: 650;
}
.legal-doc h2:first-child {
  margin-top: 0;
}
.legal-doc ul {
  margin: 0 0 16px;
  padding-left: 1.2rem;
  color: var(--muted);
  font-size: 1.02rem;
  line-height: 1.85;
}
.legal-doc li {
  margin-bottom: 8px;
}
.legal-doc a {
  color: #2563eb;
  text-decoration: none;
}
.legal-doc a:hover {
  color: #1d4ed8;
}
.legal-doc strong {
  color: #334155;
  font-weight: 600;
}

@media (prefers-reduced-motion: reduce) {
  .hero::before, .hero-copy, .hero .cta, .hero-visual, .hero h1 .brand-grad, .hero h1 .grad, .hero-visual-floating img,
  .dl-hero h1, .dl-hero h1 .brand-grad, .dl-hero h1 .grad, .dl-hero .lead,
  .not-found-code { animation: none; }
  .track { transition: none; }
  .chapter .copy .no,
  .chapter .copy h2,
  .chapter .copy .body,
  .chapter .copy .points li {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .media-floating img { animation: none; }
}