:root {
  --bg: #f5f7fb;
  --panel: #ffffff;
  --panel-soft: #f7f8fc;
  --panel-muted: #eef2f8;
  --line: #e7ebf2;
  --line-strong: #d8dee8;
  --text: #0b1225;
  --text-soft: #596275;
  --text-faint: #8a93a7;
  --primary: #0d1425;
  --primary-soft: #4f70ff;
  --accent: #7a7dff;
  --sky: #dff0ff;
  --violet: #e2dbff;
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
  --radius-xl: 32px;
  --radius-lg: 24px;
  --radius-md: 18px;
  --shell: min(1380px, calc(100% - 48px));
  --embed-top-offset: 0px;
  --site-header-height: 74px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  font-family:
    "Avenir Next", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  background: #fff;
}

body.is-embedded {
  padding-top: calc(var(--embed-top-offset) + var(--site-header-height));
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input {
  font: inherit;
}

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

main {
  overflow: clip;
}

[id] {
  scroll-margin-top: 88px;
}

body.is-embedded [id] {
  scroll-margin-top: calc(
    var(--embed-top-offset) + var(--site-header-height) + 14px
  );
}

.shell {
  width: var(--shell);
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(15, 23, 42, 0.06);
  backdrop-filter: blur(14px);
}

body.is-embedded .site-header {
  position: fixed;
  top: var(--embed-top-offset);
  left: 0;
  right: 0;
  background: var(--panel);
  border-bottom-color: transparent;
  backdrop-filter: none;
}

body.is-embedded .site-header .header-shell {
  visibility: hidden;
  pointer-events: none;
}

.header-shell {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 74px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.brand-mark {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  overflow: hidden;
  background: #fff;
  box-shadow: 0 6px 18px rgba(15, 23, 42, 0.06);
}

.brand-mark img {
  width: 100%;
  height: 100%;
}

.brand-name {
  font-size: 27px;
  font-weight: 800;
  letter-spacing: -0.04em;
}

.header-menu {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  width: 100%;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 auto;
}

.main-nav a {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 14px 16px;
  font-size: 15px;
  font-weight: 700;
  color: #1c2537;
}

.main-nav a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -1px;
  width: 28px;
  height: 4px;
  border-radius: 999px 999px 0 0;
  background: var(--primary);
  transform: translateX(-50%) scaleX(0);
  transform-origin: center;
  transition: transform 0.2s ease;
}

.main-nav a.is-active::after,
.main-nav a:hover::after {
  transform: translateX(-50%) scaleX(1);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.header-divider {
  width: 1px;
  height: 20px;
  background: var(--line-strong);
}

.lang-dropdown {
  position: relative;
  display: inline-flex;
  align-items: center;
}

.lang-switch,
.header-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 40px;
  padding: 0 14px;
  border-radius: 999px;
  color: #364153;
  font-size: 14px;
  font-weight: 700;
  border: 1px solid transparent;
  background: transparent;
  transition:
    background 0.2s ease,
    color 0.2s ease,
    transform 0.2s ease;
}

.lang-switch {
  min-width: auto;
  padding: 0;
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  cursor: pointer;
  gap: 6px;
}

.lang-switch[aria-expanded="true"] {
  color: var(--primary);
}

.lang-switch:hover {
  color: var(--primary);
}

.lang-switch .action-icon {
  color: #697386;
}

.lang-caret {
  font-size: 10px;
  color: #98a2b3;
  line-height: 1;
}

.lang-current {
  min-width: 22px;
  text-align: center;
  font-size: 14px;
  letter-spacing: 0.02em;
}

.lang-menu {
  position: absolute;
  top: calc(100% + 10px);
  left: 0;
  z-index: 2;
  display: none;
  min-width: 138px;
  padding: 8px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
}

.lang-dropdown.is-open .lang-menu {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.lang-option {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 10px 12px;
  border: 0;
  border-radius: 12px;
  background: transparent;
  color: #1c2537;
  font-size: 14px;
  font-weight: 700;
  text-align: left;
  cursor: pointer;
  transition:
    background 0.2s ease,
    color 0.2s ease,
    transform 0.2s ease;
}

.lang-option:hover {
  background: rgba(15, 23, 42, 0.05);
  transform: translateY(-1px);
}

.lang-option.is-active {
  color: var(--primary-soft);
  background: rgba(79, 112, 255, 0.12);
}

.lang-flag {
  display: inline-block;
  width: 20px;
  height: 14px;
  flex: 0 0 auto;
  border-radius: 3px;
  background-repeat: no-repeat;
  background-position: center;
  background-size: cover;
  box-shadow:
    0 0 0 1px rgba(15, 23, 42, 0.08),
    0 2px 5px rgba(15, 23, 42, 0.12);
}

.lang-flag.is-cn {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 28 20'%3E%3Crect width='28' height='20' rx='3' fill='%23de2910'/%3E%3Cpath fill='%23ffde00' d='M7 3.1l.86 2.63h2.77L8.39 7.33l.86 2.63L7 8.35 4.75 9.96l.86-2.63-2.24-1.6h2.77z'/%3E%3C/svg%3E");
}

.lang-flag.is-en {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 28 20'%3E%3Crect width='28' height='20' rx='3' fill='%23012169'/%3E%3Cpath fill='%23fff' d='M0 0h4.2L28 15.8V20h-4.2L0 4.2zM23.8 0H28v4.2L4.2 20H0v-4.2z'/%3E%3Cpath fill='%23c8102e' d='M0 0h2.1L28 17.3V20h-2.1L0 2.7zM25.9 0H28v2.7L2.1 20H0v-2.7z'/%3E%3Cpath fill='%23fff' d='M11 0h6v20h-6zM0 7h28v6H0z'/%3E%3Cpath fill='%23c8102e' d='M12.2 0h3.6v20h-3.6zM0 8.2h28v3.6H0z'/%3E%3C/svg%3E");
}

.trial-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 46px;
  padding: 0 18px;
  border-radius: 14px;
  background: var(--primary);
  color: #fff;
  font-size: 15px;
  font-weight: 800;
  transition:
    transform 0.25s ease,
    box-shadow 0.25s ease;
}

.action-icon,
.trial-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.action-icon svg,
.trial-icon svg {
  width: 16px;
  height: 16px;
}

.lang-switch:hover,
.header-link:hover {
  background: rgba(15, 23, 42, 0.05);
  transform: translateY(-1px);
}

.lang-switch:hover {
  background: transparent;
  transform: none;
}

.trial-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 30px rgba(15, 23, 42, 0.18);
}

.mobile-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fff;
  cursor: pointer;
}

.mobile-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  border-radius: 999px;
  background: var(--primary);
}

.section-block {
  padding: 68px 0;
}

.hero-section {
  position: relative;
  overflow: hidden;
  padding: 32px 0 72px;
  background:
    radial-gradient(
      circle at 16% 20%,
      rgba(206, 236, 255, 0.95),
      transparent 28%
    ),
    radial-gradient(
      circle at 84% 18%,
      rgba(214, 225, 255, 0.88),
      transparent 24%
    ),
    radial-gradient(
      circle at 60% 82%,
      rgba(213, 205, 255, 0.76),
      transparent 30%
    ),
    linear-gradient(180deg, #f6fbff 0%, #eaf1ff 60%, #f6f9ff 100%);
}

.hero-backdrop {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(
      circle at 55% 55%,
      rgba(86, 129, 255, 0.12),
      transparent 28%
    ),
    radial-gradient(
      circle at 46% 35%,
      rgba(129, 160, 255, 0.16),
      transparent 18%
    );
  pointer-events: none;
}

.hero-shell {
  position: relative;
  text-align: center;
  padding: 78px 0 70px;
}

.hero-shell > * {
  position: relative;
  z-index: 1;
}

.hero-orb {
  position: absolute;
  border-radius: 999px;
  pointer-events: none;
  opacity: 0.8;
  animation: floaty 8s ease-in-out infinite;
}

.orb-a {
  top: 118px;
  left: 27%;
  width: 180px;
  height: 180px;
  background: radial-gradient(
    circle,
    rgba(122, 165, 255, 0.26),
    rgba(122, 165, 255, 0.05)
  );
}

.orb-b {
  top: 28px;
  right: 10%;
  width: 360px;
  height: 360px;
  border: 1px solid rgba(206, 221, 255, 0.8);
  background: rgba(255, 255, 255, 0.08);
  animation-delay: -2s;
}

.orb-c {
  top: 96px;
  right: 15%;
  width: 116px;
  height: 116px;
  border: 1px solid rgba(216, 228, 255, 0.9);
  background: rgba(255, 255, 255, 0.16);
  animation-delay: -4s;
}

.hero-kicker,
.section-label {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  padding: 0 14px;
  border: 1px solid #e5e9f3;
  border-radius: 999px;
  color: #6c7af5;
  background: rgba(255, 255, 255, 0.92);
  font-size: 13px;
  font-weight: 700;
}

.hero-title,
.section-heading h2,
.playground-copy h2,
.contact-card h2 {
  margin: 22px 0 0;
  font-size: clamp(34px, 4.8vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.05em;
  font-weight: 800;
}

.section-heading h2,
.playground-copy h2,
.contact-card h2 {
  font-size: clamp(28px, 3.2vw, 44px);
}

.steps-section .section-heading h2 span {
  color: #7e7cff;
}

.section-heading p,
.playground-copy p,
.contact-card p {
  margin: 18px auto 0;
  max-width: 820px;
  color: var(--text-soft);
  font-size: 16px;
  line-height: 1.8;
}

.hero-kicker,
.hero-title,
.hero-actions,
.model-item.is-entering {
  animation: riseIn 0.8s ease both;
}

.hero-kicker {
  animation-delay: 0.05s;
}

.hero-title {
  animation-delay: 0.12s;
}

.hero-actions {
  animation-delay: 0.3s;
}

.model-item.is-entering {
  animation-duration: 0.42s;
  animation-delay: var(--card-enter-delay, 0ms);
}

.hero-actions,
.contact-actions {
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  margin-top: 28px;
}

.hero-primary,
.hero-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 62px;
  padding: 0 34px;
  border-radius: 14px;
  font-size: 17px;
  font-weight: 800;
  transition:
    transform 0.25s ease,
    box-shadow 0.25s ease,
    background 0.25s ease;
}

.hero-primary {
  gap: 16px;
  color: #fff;
  background: var(--primary);
}

.hero-arrow {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.18);
}

.hero-secondary {
  color: var(--primary);
  background: rgba(255, 255, 255, 0.58);
  border: 1px solid rgba(15, 23, 42, 0.16);
}

.hero-primary:hover,
.hero-secondary:hover {
  transform: translateY(-2px);
}

.hero-primary:hover {
  box-shadow: 0 18px 34px rgba(15, 23, 42, 0.18);
}

.hero-secondary:hover {
  background: rgba(255, 255, 255, 0.86);
}

[data-aos] {
  transition:
    opacity 0.56s ease,
    transform 0.56s ease;
  transition-delay: var(--reveal-delay, 0ms);
}

.reveal-ready[data-aos="fade-up"] {
  opacity: 0;
  transform: translate3d(0, 22px, 0);
}

.reveal-ready[data-aos="fade-left"] {
  opacity: 0;
  transform: translate3d(26px, 0, 0);
}

.reveal-ready[data-aos="fade-right"] {
  opacity: 0;
  transform: translate3d(-26px, 0, 0);
}

.reveal-ready[data-aos="zoom-in-up"] {
  opacity: 0;
  transform: translate3d(0, 24px, 0) scale(0.97);
}

.reveal-ready.is-visible {
  opacity: 1;
  transform: none;
}

.search-box {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 72px;
  padding: 0 22px 0 64px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
  box-shadow: 0 2px 10px rgba(15, 23, 42, 0.03);
}

.model-intro {
  margin-bottom: 24px;
}

.search-icon {
  position: absolute;
  left: 22px;
  width: 24px;
  height: 24px;
  border: 3px solid #9aa3b2;
  border-radius: 999px;
}

.search-icon::after {
  content: "";
  position: absolute;
  right: -8px;
  bottom: -5px;
  width: 10px;
  height: 3px;
  border-radius: 999px;
  background: #9aa3b2;
  transform: rotate(45deg);
}

.search-box input {
  width: 100%;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--text);
  font-size: 16px;
}

.filter-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 26px;
}

.filter-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 999px;
  background: #f1f2f6;
  color: #222d40;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition:
    transform 0.2s ease,
    background 0.2s ease,
    color 0.2s ease,
    box-shadow 0.2s ease;
}

.filter-chip:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 18px rgba(15, 23, 42, 0.06);
}

.filter-chip.is-active {
  background: var(--primary);
  color: #fff;
}

.chip-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 18px;
  border-radius: 999px;
  background: rgba(15, 20, 37, 0.08);
}

.chip-icon svg {
  width: 14px;
  height: 14px;
}

.filter-chip.is-active .chip-icon {
  background: rgba(255, 255, 255, 0.16);
}

.model-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 28px;
}

.model-item {
  display: flex;
  align-items: stretch;
  gap: 16px;
  min-height: 168px;
  padding: 22px 22px 20px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #fff;
  transition:
    transform 0.2s ease,
    box-shadow 0.2s ease,
    border-color 0.2s ease;
}

.model-item:hover {
  transform: translateY(-2px);
  border-color: #d7e0f1;
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.06);
}

.model-main {
  width: 100%;
  min-width: 0;
}

.model-head {
  display: flex;
  align-items: center;
  gap: 16px;
}

.model-logo {
  width: 56px;
  height: 56px;
  border-radius: 12px;
  overflow: hidden;
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4px;
  background: #fff;
  border: 1px solid #f0f2f7;
}

.model-logo img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.model-logo.is-icon {
  padding: 0;
  border: 0;
  background: linear-gradient(135deg, #eff4ff, #e6ecff);
  color: #4f70ff;
}

.model-logo.is-badge {
  padding: 0;
  border: 0;
  background: linear-gradient(135deg, #eff4ff, #e6ecff);
  color: #4f70ff;
}

.model-logo.is-icon svg {
  width: 26px;
  height: 26px;
}

.model-logo-text {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 10px;
  min-height: 24px;
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.model-logo.tone-violet {
  background: linear-gradient(135deg, #ede5ff, #e3d8ff);
  color: #7658ff;
}

.model-logo.tone-sky {
  background: linear-gradient(135deg, #e5f5ff, #d9efff);
  color: #2176d9;
}

.model-logo.tone-emerald {
  background: linear-gradient(135deg, #e2fbf3, #d5f5ea);
  color: #0f9c74;
}

.model-logo.tone-amber {
  background: linear-gradient(135deg, #fff0d8, #ffe5b9);
  color: #c27c0d;
}

.model-logo.tone-dark {
  background: linear-gradient(135deg, #1f2940, #111827);
  color: #ffffff;
}

.model-title {
  font-size: 18px;
  font-weight: 800;
  line-height: 1.3;
}

.model-provider {
  margin-top: 6px;
  color: var(--text-faint);
  font-size: 13px;
  font-weight: 700;
  line-height: 1.4;
}

.model-type {
  margin-top: 20px;
  color: #9aa3b2;
  font-size: 13px;
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.tag-row span {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 0 10px;
  border-radius: 8px;
  background: #edf2ff;
  color: #3d4e74;
  font-size: 12px;
  font-weight: 700;
}

.model-actions {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin-top: 34px;
  flex-wrap: wrap;
}

.model-action-button {
  min-width: 112px;
  min-height: 54px;
  padding: 0 22px;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: #ffffff;
  color: #202a3d;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  transition:
    transform 0.22s ease,
    box-shadow 0.22s ease,
    background 0.22s ease,
    color 0.22s ease;
}

.model-action-button:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 18px rgba(15, 23, 42, 0.07);
}

.model-action-button.is-primary {
  background: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
}

.section-heading {
  text-align: center;
}

.pricing-grid,
.step-grid,
.resource-grid {
  display: grid;
  gap: 18px;
  margin-top: 32px;
}

.pricing-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.step-grid {
  --step-gap: 36px;
  --step-connector-width: 24px;
  --step-connector-height: 12px;
  gap: var(--step-gap);
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.resource-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.info-card,
.step-card,
.resource-card,
.contact-card,
.playground-card {
  border-radius: var(--radius-xl);
  background: #fff;
  border: 1px solid var(--line);
}

.info-card {
  padding: 28px;
}

.info-icon,
.resource-icon {
  width: 36px;
  height: 36px;
  border-radius: 12px;
  background: #dbe7ff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.info-icon.purple {
  background: #e7ddff;
}

.info-icon.cyan {
  background: #daf4ff;
}

.info-icon span,
.resource-icon span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.info-icon svg,
.resource-icon svg {
  width: 18px;
  height: 18px;
  color: #4f70ff;
}

.info-card h3,
.step-card h3,
.resource-card h3 {
  margin: 18px 0 0;
  font-size: 21px;
  line-height: 1.35;
}

.info-card p,
.step-card p,
.resource-card p {
  margin: 14px 0 0;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 1.8;
}

.step-card {
  position: relative;
  overflow: visible;
  min-height: 280px;
  padding: 34px 30px 28px;
}

.step-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  margin-top: 6px;
  border-radius: 14px;
  background: #eef2ff;
}

.step-icon svg {
  width: 22px;
  height: 22px;
  color: #6f78ff;
}

.step-card:not(:last-child)::after {
  content: "";
  position: absolute;
  left: calc(100% + ((var(--step-gap) - var(--step-connector-width)) / 2));
  top: 50%;
  width: var(--step-connector-width);
  height: var(--step-connector-height);
  background: #111827;
  clip-path: polygon(
    0 42%,
    62% 42%,
    62% 10%,
    100% 50%,
    62% 90%,
    62% 58%,
    0 58%
  );
  filter: drop-shadow(0 2px 6px rgba(15, 23, 42, 0.08));
  transform: translateY(-50%);
  opacity: 0.9;
  pointer-events: none;
}

.step-tag {
  position: absolute;
  top: 0;
  left: 0;
  transform: translate(14px, -10px);
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 14px;
  border-radius: 8px;
  background: #d6ddff;
  color: #6f78ff;
  font-size: 13px;
  font-weight: 700;
}

.step-card a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 18px;
  margin-top: 28px;
  border-radius: 10px;
  background: var(--primary);
  color: #fff;
  font-size: 16px;
  font-weight: 700;
}

.playground-card {
  position: relative;
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 28px;
  padding: 40px;
  background: linear-gradient(180deg, #f4f6fa, #eef1f7);
  overflow: hidden;
}

.playground-card::before {
  content: "";
  position: absolute;
  top: -72px;
  right: -64px;
  width: 220px;
  height: 220px;
  border-radius: 999px;
  background: radial-gradient(
    circle,
    rgba(122, 125, 255, 0.2),
    rgba(122, 125, 255, 0)
  );
  pointer-events: none;
}

.playground-tabs {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 24px;
}

.playground-tabs span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 12px;
  border: 1px solid var(--line-strong);
  background: #fff;
  color: #283244;
  font-size: 15px;
  font-weight: 700;
}

.playground-tabs .is-active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.playground-demo {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 20px;
  align-items: stretch;
}

.chat-panel,
.control-box {
  border-radius: 22px;
  background: #fff;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.chat-panel {
  padding: 24px;
  min-height: 430px;
}

.chat-title {
  font-size: 30px;
  font-weight: 800;
  line-height: 1.1;
}

.chat-panel p {
  margin: 10px 0 0;
  color: var(--text-soft);
  font-size: 16px;
  line-height: 1.8;
}

.chat-bubble {
  max-width: 92%;
  padding: 16px 18px;
  margin-top: 18px;
  border-radius: 14px;
  font-size: 15px;
  line-height: 1.8;
  animation: riseIn 0.55s ease both;
}

.chat-bubble.user {
  margin-left: 32px;
  background: #f4f6fb;
  animation-delay: 0.12s;
}

.chat-bubble.ai {
  background: #eef4ff;
  animation-delay: 0.24s;
}

.control-box {
  padding: 18px;
  min-height: 430px;
}

.control-label {
  display: block;
  color: var(--text-soft);
  font-size: 14px;
  font-weight: 700;
}

.select-button,
.select-search {
  display: flex;
  align-items: center;
  min-height: 54px;
  padding: 0 16px;
  margin-top: 12px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  color: #6b7486;
  font-size: 16px;
  cursor: default;
}

.select-list {
  display: grid;
  gap: 10px;
  margin-top: 14px;
  max-height: 270px;
  overflow: auto;
  padding-right: 4px;
}

.select-item {
  padding-right: 10px;
  font-size: 15px;
  font-weight: 700;
  color: #273146;
  animation: riseIn 0.45s ease both;
  cursor: default;
}

.select-item:nth-child(2) {
  animation-delay: 0.04s;
}

.select-item:nth-child(3) {
  animation-delay: 0.08s;
}

.select-item:nth-child(4) {
  animation-delay: 0.12s;
}

.select-item:nth-child(5) {
  animation-delay: 0.16s;
}

.select-item:nth-child(6) {
  animation-delay: 0.2s;
}

.resource-card {
  padding: 32px;
  background: linear-gradient(180deg, #f4f6fa, #f1f3f8);
}

.resource-icon.gear {
  background: #dde7ff;
}

.resource-icon.chart {
  background: #e7ddff;
}

.resource-card pre {
  margin: 24px 0 0;
  padding: 22px;
  border-radius: 18px;
  background: #2d313a;
  color: #c7d58d;
  overflow: auto;
  font-size: 14px;
  line-height: 1.8;
}

.growth-chart {
  width: 100%;
  height: auto;
  margin-top: 22px;
}

.chart-area {
  opacity: 0;
  animation: riseIn 0.8s ease 0.14s forwards;
}

.chart-line {
  stroke-dasharray: 760;
  stroke-dashoffset: 760;
  animation: drawLine 1.6s ease 0.16s forwards;
}

.growth-chart circle {
  fill: #fff;
  stroke: #4f70ff;
  stroke-width: 4;
}

.chart-dot {
  opacity: 0;
  transform-origin: center;
  animation: pulseDot 0.7s ease forwards;
}

.chart-dot:nth-of-type(1) {
  animation-delay: 0.45s;
}

.chart-dot:nth-of-type(2) {
  animation-delay: 0.58s;
}

.chart-dot:nth-of-type(3) {
  animation-delay: 0.71s;
}

.chart-dot:nth-of-type(4) {
  animation-delay: 0.84s;
}

.chart-dot:nth-of-type(5) {
  animation-delay: 0.97s;
}

.faq-list {
  position: relative;
  display: grid;
  grid-template-columns: minmax(280px, 0.82fr) minmax(0, 1.18fr);
  gap: clamp(28px, 4vw, 84px);
  align-items: center;
  margin-top: 32px;
  padding: clamp(28px, 4vw, 54px);
  border: 1px solid rgba(222, 228, 241, 0.94);
  border-radius: 40px;
  background:
    radial-gradient(
      circle at 12% 18%,
      rgba(93, 123, 255, 0.12),
      transparent 34%
    ),
    radial-gradient(
      circle at 84% 82%,
      rgba(140, 156, 255, 0.1),
      transparent 28%
    ),
    linear-gradient(180deg, #f8faff 0%, #f3f6fd 100%);
  box-shadow: 0 26px 68px rgba(15, 23, 42, 0.08);
  overflow: hidden;
}

.faq-list::before {
  content: "";
  position: absolute;
  left: -36px;
  top: 38px;
  width: 280px;
  height: 280px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.78);
  filter: blur(14px);
}

.faq-copy,
.faq-items {
  position: relative;
  z-index: 1;
}

.faq-copy {
  max-width: 450px;
}

.faq-eyebrow {
  box-shadow: 0 12px 30px rgba(79, 112, 255, 0.12);
}

.faq-copy h2 {
  margin: 22px 0 0;
  font-size: clamp(28px, 3.2vw, 46px);
  line-height: 0.96;
  letter-spacing: -0.06em;
  font-weight: 900;
}

.faq-copy h2 span {
  background: linear-gradient(90deg, #4b73ff 0%, #8a7dff 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.faq-copy p {
  margin: 24px 0 0;
  max-width: 420px;
  color: #4d5870;
  font-size: 14px;
  line-height: 1.9;
}

.faq-items {
  display: grid;
  gap: 18px;
  counter-reset: faq-item;
}

.faq-item {
  counter-increment: faq-item;
  border: 1px solid rgba(225, 230, 241, 0.96);
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 10px 26px rgba(15, 23, 42, 0.04);
  overflow: hidden;
  transition:
    transform 0.22s ease,
    border-color 0.22s ease,
    box-shadow 0.22s ease,
    background 0.22s ease;
}

.faq-item:hover {
  transform: translateY(-2px);
  border-color: rgba(79, 112, 255, 0.24);
  box-shadow: 0 18px 36px rgba(79, 112, 255, 0.12);
}

.faq-item[open] {
  border-color: rgba(79, 112, 255, 0.24);
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 20px 42px rgba(79, 112, 255, 0.14);
}

.faq-item summary {
  position: relative;
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 28px 76px 28px 28px;
  cursor: pointer;
  list-style: none;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.45;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::marker {
  content: "";
}

.faq-item summary::before {
  content: counter(faq-item) ".";
  flex: 0 0 auto;
  color: #0f172a;
  font-variant-numeric: tabular-nums;
}

.faq-item summary::after {
  content: "";
  position: absolute;
  top: 50%;
  right: 30px;
  width: 14px;
  height: 14px;
  border-right: 2.5px solid #7b8499;
  border-bottom: 2.5px solid #7b8499;
  transform: translateY(-65%) rotate(45deg);
  transition:
    transform 0.22s ease,
    border-color 0.22s ease;
}

.faq-item[open] summary::after {
  transform: translateY(-35%) rotate(225deg);
  border-color: #4f70ff;
}

.faq-answer {
  margin: 0;
  padding: 0 28px 24px 66px;
  color: #5d677b;
  font-size: 14px;
  line-height: 1.85;
}

.faq-item[open] .faq-answer {
  padding-top: 18px;
  border-top: 1px solid rgba(229, 234, 244, 0.94);
}

.faq-answer code {
  display: inline-flex;
  align-items: center;
  min-height: 26px;
  padding: 0 8px;
  border-radius: 999px;
  background: #eef3ff;
  color: #3552d3;
  font-size: 0.92em;
}

.contact-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  padding: 36px 40px;
  background: linear-gradient(180deg, #f4f6fb, #eef2ff);
}

.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 28;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border: 0;
  border-radius: 999px;
  background: #4f70ff;
  color: #fff;
  box-shadow: 0 16px 30px rgba(79, 112, 255, 0.3);
  font-size: 28px;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition:
    opacity 0.2s ease,
    transform 0.2s ease,
    box-shadow 0.2s ease,
    background 0.2s ease;
}

.back-to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.back-to-top svg {
  width: 22px;
  height: 22px;
}

.back-to-top:hover {
  background: #3e60f6;
  box-shadow: 0 20px 36px rgba(79, 112, 255, 0.36);
}

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

@keyframes floaty {
  0%,
  100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-10px);
  }
}

@keyframes drawLine {
  to {
    stroke-dashoffset: 0;
  }
}

@keyframes pulseDot {
  0% {
    opacity: 0;
    transform: scale(0.6);
  }
  70% {
    opacity: 1;
    transform: scale(1.12);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

.contact-card h2 {
  max-width: 760px;
}

.contact-card p {
  margin-left: 0;
  max-width: 680px;
}

.site-footer {
  margin-top: 72px;
  border-top: 1px solid #e6ecf5;
  background: #f3f6fb;
}

.site-footer__main {
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(
      circle at 12% 18%,
      rgba(122, 125, 255, 0.1),
      transparent 22%
    ),
    radial-gradient(
      circle at 82% 10%,
      rgba(79, 112, 255, 0.08),
      transparent 20%
    ),
    #f3f6fb;
}

.site-footer__main-shell {
  display: grid;
  grid-template-columns: minmax(280px, 1.35fr) repeat(3, minmax(140px, 0.82fr));
  gap: 36px 44px;
  padding: 56px 0 44px;
}

.site-footer__brand {
  display: flex;
  flex-direction: column;
  gap: 18px;
  min-width: 0;
}

.site-footer__logo {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  width: fit-content;
}

.site-footer__logo-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 16px;
  border: 1px solid rgba(216, 222, 232, 0.96);
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 14px 32px rgba(15, 23, 42, 0.08);
}

.site-footer__logo-mark img {
  width: 32px;
  height: 32px;
  object-fit: contain;
}

.site-footer__logo-name {
  font-size: 30px;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: #0f172a;
}

.site-footer__description {
  max-width: 340px;
  margin: 0;
  color: #667085;
  font-size: 14px;
  line-height: 1.8;
}

.site-footer__column {
  min-width: 0;
}

.site-footer__heading {
  margin: 4px 0 16px;
  color: #111827;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.site-footer__nav {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.site-footer__nav a {
  color: #475467;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.5;
  transition:
    color 0.2s ease,
    transform 0.2s ease;
}

.site-footer__nav a:hover {
  color: #111827;
  transform: translateX(2px);
}

.site-footer__bar {
  background: #020617;
  color: #f8fafc;
}

.site-footer__bar-shell {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 64px;
}

.site-footer__legal {
  color: rgba(248, 250, 252, 0.84);
  font-size: 13px;
  line-height: 1.6;
}

.site-footer__legal-zh,
.site-footer__legal-en {
  display: none;
}

html[lang^="zh"] .site-footer__legal-zh {
  display: inline;
}

html[lang="en"] .site-footer__legal-en {
  display: inline;
}

.site-footer__bar-links {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  flex-wrap: wrap;
}

.site-footer__bar-links-zh,
.site-footer__bar-links-en {
  display: none;
  align-items: center;
  justify-content: flex-end;
  gap: 28px;
  flex-wrap: wrap;
}

html[lang^="zh"] .site-footer__bar-links-zh {
  display: flex;
}

html[lang="en"] .site-footer__bar-links-en {
  display: flex;
}

.site-footer__bar-links a,
.site-footer__link {
  color: rgba(248, 250, 252, 0.92);
  font-size: 13px;
  line-height: 1.6;
  text-decoration: none;
  transition: color 0.2s ease;
}

.site-footer__bar-links a:hover,
.site-footer__link:hover {
  color: #ffffff;
}

.is-hidden {
  display: none;
}

@media (max-width: 1280px) {
  .step-grid {
    --step-gap: 26px;
    --step-connector-width: 20px;
    --step-connector-height: 10px;
  }

  .orb-b,
  .orb-c {
    display: none;
  }

  .pricing-grid,
  .resource-grid,
  .playground-card,
  .playground-demo {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .playground-copy {
    grid-column: 1 / -1;
  }
}

@media (max-width: 980px) {
  .mobile-toggle {
    display: inline-block;
  }

  .header-menu {
    position: absolute;
    left: 24px;
    right: 24px;
    top: calc(100% + 12px);
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 18px;
    border: 1px solid var(--line);
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow);
  }

  .header-menu.is-open {
    display: flex;
  }

  .main-nav,
  .header-actions {
    flex-direction: column;
    align-items: stretch;
    width: 100%;
  }

  .header-divider {
    display: none;
  }

  .lang-dropdown {
    width: 100%;
  }

  .main-nav a,
  .lang-switch,
  .header-link,
  .trial-button {
    justify-content: center;
    text-align: center;
  }

  .lang-switch {
    width: 100%;
  }

  .lang-menu {
    position: static;
    min-width: 0;
    width: 100%;
    margin-top: 8px;
    box-shadow: none;
  }

  .lang-option {
    justify-content: center;
    text-align: center;
  }

  .brand-name {
    font-size: 26px;
  }

  .orb-a {
    left: 10%;
  }

  .model-grid,
  .pricing-grid,
  .step-grid,
  .resource-grid,
  .playground-card,
  .playground-demo,
  .faq-list {
    grid-template-columns: 1fr;
  }

  .faq-list {
    gap: 30px;
    align-items: stretch;
  }

  .faq-copy {
    max-width: none;
  }

  .step-card::before,
  .step-card::after {
    display: none;
  }

  .contact-card {
    flex-direction: column;
    align-items: flex-start;
  }

  .site-footer__main-shell {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px 28px;
  }

  .site-footer__brand {
    grid-column: 1 / -1;
  }

  .site-footer__bar-shell {
    min-height: 60px;
    gap: 16px;
  }
}

@media (max-width: 720px) {
  :root {
    --shell: min(100% - 24px, 1380px);
  }

  .hero-shell {
    padding: 48px 0 56px;
  }

  .hero-title,
  .section-heading h2,
  .playground-copy h2,
  .contact-card h2 {
    font-size: 32px;
  }

  .orb-a {
    width: 140px;
    height: 140px;
    top: 132px;
  }

  .hero-primary,
  .hero-secondary {
    width: 100%;
  }

  .site-footer {
    margin-top: 56px;
  }

  .site-footer__main-shell {
    grid-template-columns: 1fr;
    gap: 28px;
    padding: 42px 0 32px;
  }

  .site-footer__logo-name {
    font-size: 26px;
  }

  .site-footer__heading {
    margin-bottom: 12px;
    font-size: 16px;
  }

  .site-footer__description,
  .site-footer__nav a {
    font-size: 13px;
  }

  .site-footer__bar-shell {
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    padding: 14px 0;
  }

  .site-footer__bar-links {
    justify-content: flex-start;
    gap: 18px;
  }

  .model-item,
  .playground-card,
  .resource-card,
  .contact-card,
  .faq-list {
    padding: 22px;
  }

  .model-grid {
    gap: 12px;
  }

  .faq-list {
    gap: 24px;
    border-radius: 28px;
  }

  .faq-copy h2 {
    font-size: 24px;
    line-height: 1.02;
  }

  .faq-copy p {
    margin-top: 18px;
    font-size: 12px;
    line-height: 1.8;
  }

  .faq-item {
    border-radius: 20px;
  }

  .faq-item summary {
    gap: 14px;
    padding: 20px 58px 20px 20px;
    font-size: 16px;
  }

  .faq-item summary::after {
    right: 22px;
    width: 12px;
    height: 12px;
  }

  .faq-answer {
    padding: 0 20px 18px 52px;
    font-size: 13px;
  }

  .faq-item[open] .faq-answer {
    padding-top: 14px;
  }

  .model-item {
    flex-direction: column;
  }

  .model-action-button {
    width: 100%;
  }
}