/* DingdongBot — clean white / sharp blue, minimal tech */
:root {
  --bg: #ffffff;
  --bg-soft: #f7f9fc;
  --bg-card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --line-strong: #cbd5e1;
  --accent: #2563eb;
  --accent-deep: #1d4ed8;
  --accent-soft: #eff6ff;
  --shadow: 0 1px 0 rgba(15, 23, 42, 0.04), 0 8px 24px rgba(15, 23, 42, 0.04);
  --radius: 14px;
  --max: 1080px;
  --font: "Inter", "SF Pro Display", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}
a { color: inherit; text-decoration: none; }
.wrap { width: min(100% - 2.5rem, var(--max)); margin-inline: auto; }

/* Nav */
.nav {
  position: sticky; top: 0; z-index: 40;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.brand {
  font-weight: 700; letter-spacing: -0.03em; font-size: 1.05rem;
  display: flex; align-items: center; gap: .5rem;
}
.brand-mark {
  width: 20px; height: 20px; border-radius: 5px;
  background: linear-gradient(135deg, #3b82f6, #1d4ed8);
}
.brand span { color: var(--muted); font-weight: 500; font-size: .9rem; }
.nav nav { display: flex; align-items: center; gap: 1.35rem; }
.nav nav a { color: var(--muted); font-size: .9rem; transition: color .15s; }
.nav nav a:hover { color: var(--accent-deep); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--accent);
  color: #fff !important;
  border-radius: 9px; padding: .7rem 1.25rem;
  font-weight: 600; font-size: .9rem;
  border: 1px solid var(--accent-deep);
  box-shadow: 0 1px 2px rgba(29, 78, 216, 0.2);
  transition: background .15s, transform .15s;
}
.btn:hover { background: var(--accent-deep); }
.btn-sm { padding: .4rem .9rem; font-size: .82rem; border-radius: 8px; }
.btn-ghost {
  background: #fff;
  color: var(--accent-deep) !important;
  border: 1px solid var(--line-strong);
  box-shadow: none;
}
.btn-ghost:hover { background: var(--accent-soft); border-color: #93c5fd; }
.btn-block { width: 100%; margin-top: 1.25rem; }

/* Hero */
.hero {
  padding: 4.5rem 0 2.5rem;
  text-align: center;
  position: relative;
  background:
    linear-gradient(180deg, #f8fbff 0%, #ffffff 55%);
  border-bottom: 1px solid var(--line);
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(37, 99, 235, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(37, 99, 235, 0.045) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(180deg, #000 0%, transparent 85%);
  pointer-events: none;
}
.hero > * { position: relative; z-index: 1; }
.eyebrow {
  display: inline-flex; align-items: center; gap: .4rem;
  color: var(--accent-deep);
  font-size: .76rem; font-weight: 650; letter-spacing: .1em; text-transform: uppercase;
  margin-bottom: 1.15rem;
  padding: .3rem .75rem;
  border: 1px solid #bfdbfe;
  border-radius: 999px;
  background: #fff;
}
.eyebrow::before {
  content: ""; width: 6px; height: 6px; border-radius: 50%;
  background: var(--accent);
  animation: node-pulse 2.4s ease-in-out infinite;
}
@keyframes node-pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: .55; transform: scale(0.85); }
}
.hero h1 {
  font-size: clamp(2.1rem, 5vw, 3.35rem);
  line-height: 1.12; letter-spacing: -0.04em; font-weight: 760;
  margin-bottom: 1rem;
  color: var(--text);
}
.lead {
  max-width: 34rem; margin: 0 auto 1.75rem;
  color: var(--muted); font-size: 1.05rem;
}
.hero-actions { display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap; }

/* Hero carousel — restrained tech motion */
.hero-stage {
  margin: 2.75rem auto 0;
  max-width: 820px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
  box-shadow: var(--shadow);
  overflow: hidden;
  text-align: left;
  position: relative;
}
.hero-stage::after {
  content: "";
  position: absolute; left: 0; right: 0; top: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(37,99,235,.55), transparent);
  animation: scan-x 4.5s linear infinite;
  pointer-events: none;
  opacity: .7;
}
@keyframes scan-x {
  0% { transform: translateX(-40%); opacity: 0; }
  15% { opacity: .7; }
  50% { opacity: .5; }
  85% { opacity: .7; }
  100% { transform: translateX(40%); opacity: 0; }
}
.carousel {
  position: relative;
  min-height: 168px;
}
.carousel-slide {
  position: absolute; inset: 0;
  padding: 1.5rem 1.6rem 1.35rem;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity .55s ease, transform .55s ease;
  pointer-events: none;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.15rem;
  align-items: start;
}
.carousel-slide.is-active {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
  position: relative;
}
.slide-mark {
  width: 44px; height: 44px; border-radius: 11px;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-soft);
  border: 1px solid #bfdbfe;
  color: var(--accent-deep);
  font-weight: 750; font-size: .85rem;
  letter-spacing: -0.02em;
}
.slide-body h3 {
  font-size: 1.05rem; letter-spacing: -0.02em; margin-bottom: .35rem; font-weight: 700;
}
.slide-body p { color: var(--muted); font-size: .92rem; max-width: 46rem; }
.carousel-bar {
  display: flex; align-items: center; gap: .75rem;
  padding: 0 1.35rem 1.1rem;
}
.carousel-progress {
  flex: 1; height: 2px; background: var(--line);
  border-radius: 999px; overflow: hidden;
}
.carousel-progress > span {
  display: block; height: 100%; width: 0%;
  background: var(--accent);
  border-radius: inherit;
  transition: width .05s linear;
}
.carousel-dots { display: flex; gap: .4rem; }
.carousel-dots button {
  width: 7px; height: 7px; border-radius: 50%;
  border: 0; padding: 0; cursor: pointer;
  background: #cbd5e1;
  transition: background .2s, transform .2s;
}
.carousel-dots button.is-active {
  background: var(--accent);
  transform: scale(1.15);
}

.hero-stats {
  display: flex; justify-content: center; gap: 2.25rem; flex-wrap: wrap;
  margin-top: 2.25rem; padding-top: 1.75rem;
  border-top: 1px solid var(--line);
  max-width: 820px; margin-inline: auto;
}
.hero-stats div { text-align: center; }
.hero-stats strong {
  display: block; font-size: 1.25rem; font-weight: 750; letter-spacing: -0.02em;
}
.hero-stats span { font-size: .78rem; color: var(--muted); }

/* Features */
.features {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: .9rem;
  padding: 2.75rem 0 1.5rem;
}
.feat {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.35rem 1.3rem;
  transition: border-color .15s;
}
.feat:hover { border-color: #93c5fd; }
.feat-icon {
  width: 32px; height: 32px; border-radius: 8px; margin-bottom: .9rem;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-soft);
  border: 1px solid #bfdbfe;
  color: var(--accent-deep); font-size: .8rem; font-weight: 700;
}
.feat h3 { font-size: 1rem; margin-bottom: .35rem; letter-spacing: -0.02em; }
.feat p { color: var(--muted); font-size: .9rem; }

/* Models */
.models, .pricing, .cta { padding: 2.5rem 0 3.25rem; }
.models h2, .pricing h2, .cta h2 {
  text-align: center;
  font-size: clamp(1.45rem, 3vw, 1.8rem);
  letter-spacing: -0.03em; margin-bottom: .55rem; font-weight: 750;
}
.section-desc {
  text-align: center; color: var(--muted); max-width: 36rem;
  margin: 0 auto 2rem; font-size: .94rem;
}
.section-desc strong { color: var(--accent-deep); font-weight: 650; }
.legal-note {
  text-align: center; color: #94a3b8; font-size: .78rem;
  margin: 1.15rem auto 0; max-width: 40rem;
}

.model-grid {
  list-style: none; display: grid;
  grid-template-columns: repeat(3, 1fr); gap: .85rem;
}
.model-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1.15rem 1.15rem 1rem;
  display: flex; flex-direction: column; gap: .75rem;
  transition: border-color .15s, box-shadow .15s;
}
.model-card:hover {
  border-color: #93c5fd;
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.06);
}
.model-top {
  display: flex; align-items: center; gap: .75rem;
}
.model-logo {
  width: 40px; height: 40px; border-radius: 10px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
  overflow: hidden;
}
.model-logo img {
  width: 24px; height: 24px; display: block;
  object-fit: contain;
}
.model-logo.is-mono img { filter: none; color: #0f172a; }
.model-name {
  font-weight: 700; font-size: .98rem; letter-spacing: -0.02em;
  line-height: 1.25;
}
.model-sub {
  font-size: .78rem; color: var(--muted); margin-top: .1rem;
}
.model-foot {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: .65rem; border-top: 1px solid var(--line);
  margin-top: auto;
}
.model-tag {
  font-size: .72rem; color: var(--accent-deep); font-weight: 600;
  background: var(--accent-soft);
  border: 1px solid #bfdbfe;
  border-radius: 999px;
  padding: .15rem .55rem;
}
.model-link {
  font-size: .8rem; font-weight: 600; color: var(--muted);
  display: inline-flex; align-items: center; gap: .25rem;
}
.model-link:hover { color: var(--accent-deep); }
.model-link::after { content: "↗"; font-size: .75rem; }

/* Pricing — keep structure/content */
.price-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: .9rem;
  align-items: stretch;
}
.card {
  position: relative;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.6rem 1.4rem;
  display: flex; flex-direction: column;
}
.card-featured {
  border-color: #93c5fd;
  background: linear-gradient(180deg, #f8fbff, #ffffff);
  box-shadow: 0 0 0 1px rgba(37, 99, 235, 0.08), 0 12px 32px rgba(37, 99, 235, 0.08);
  transform: translateY(-3px);
}
.badge {
  position: absolute; top: .95rem; right: .95rem;
  background: var(--accent);
  color: #fff;
  font-size: .7rem; font-weight: 700; letter-spacing: .04em;
  padding: .22rem .55rem; border-radius: 999px;
}
.card h3 { font-size: .98rem; margin-bottom: .45rem; color: var(--muted); font-weight: 650; }
.card-featured h3 { color: var(--accent-deep); }
.price {
  font-size: 2.35rem; font-weight: 760; letter-spacing: -0.04em;
  margin-bottom: 1rem; line-height: 1;
}
.price span:first-child { font-size: 1.1rem; margin-right: .08rem; font-weight: 650; }
.price span:last-child { font-size: .88rem; color: var(--muted); font-weight: 500; margin-left: .15rem; }
.card ul { list-style: none; flex: 1; }
.card li {
  color: var(--muted); font-size: .88rem; padding: .48rem 0;
  border-top: 1px solid var(--line);
}
.card li:first-child { border-top: 0; }
.card li strong { color: var(--text); font-weight: 650; }
.credit {
  margin-top: .75rem;
  padding: .7rem .85rem;
  border-radius: 10px;
  background: var(--accent-soft);
  border: 1px solid #bfdbfe;
  color: var(--accent-deep);
  font-size: .86rem; font-weight: 650;
  text-align: center;
}

/* CTA */
.cta {
  text-align: center;
  margin: .5rem auto 1.5rem;
  padding: 2.75rem 2rem !important;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: var(--bg-soft);
}
.cta p { color: var(--muted); max-width: 30rem; margin: 0 auto 1.25rem; }
.muted { margin-top: 1rem; font-size: .86rem; color: var(--muted); }

.footer {
  border-top: 1px solid var(--line);
  padding: 1.5rem 0 2rem;
  color: var(--muted); font-size: .86rem;
}
.footer-inner {
  display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
}
.footer a { color: var(--muted); }
.footer a:hover { color: var(--accent-deep); }

@media (prefers-reduced-motion: reduce) {
  .carousel-slide { transition: none; }
  .hero-stage::after, .eyebrow::before { animation: none; }
}
@media (max-width: 860px) {
  .features, .price-grid, .model-grid { grid-template-columns: 1fr; }
  .nav nav a:not(.btn) { display: none; }
  .hero { padding-top: 3.25rem; }
  .card-featured { transform: none; }
  .hero-stats { gap: 1.25rem; }
  .cta { margin-inline: 1.25rem; padding: 2rem 1.15rem !important; }
  .carousel-slide { grid-template-columns: 1fr; }
}