/* ── Design tokens (aligned with app.xingchengai.cn) ── */
:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --border: #e5e7eb;
  --text: #1f2937;
  --text-muted: #6b7280;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-soft: #eff6ff;
  --radius: 12px;
  --radius-lg: 20px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 20px 45px -20px rgba(37, 99, 235, 0.35), 0 8px 24px -12px rgba(0, 0, 0, 0.12);

  font-family: system-ui, -apple-system, 'Segoe UI', 'Microsoft YaHei', Roboto,
    'Helvetica Neue', Arial, sans-serif;
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  min-height: 100vh;
}

html {
  scroll-behavior: smooth;
}

h1,
h2,
h3 {
  margin: 0;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

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

.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: inherit;
  font-weight: 600;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.06s ease, background 0.15s ease, box-shadow 0.15s ease,
    border-color 0.15s ease;
  padding: 10px 18px;
  font-size: 0.95rem;
  white-space: nowrap;
}
.btn:active {
  transform: translateY(1px);
}
.btn--sm {
  padding: 7px 14px;
  font-size: 0.88rem;
}
.btn--lg {
  padding: 13px 26px;
  font-size: 1.02rem;
}
.btn--block {
  width: 100%;
}
.btn--primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 6px 16px -6px rgba(37, 99, 235, 0.6);
}
.btn--primary:hover {
  background: var(--primary-hover);
}
.btn--ghost {
  background: var(--surface);
  border-color: var(--border);
  color: var(--text);
}
.btn--ghost:hover {
  border-color: #cbd5e1;
  background: #fbfbfc;
}

/* ── Pills ── */
.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
  background: rgba(37, 99, 235, 0.1);
  color: var(--primary);
  border: 1px solid rgba(37, 99, 235, 0.16);
}
.pill--soft {
  background: var(--primary-soft);
}

/* ── Header ── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
}
.brand__logo {
  display: inline-flex;
  color: var(--primary);
}
.brand__name {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}
.nav__links {
  display: flex;
  align-items: center;
  gap: 26px;
}
.nav__links a {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 500;
  transition: color 0.15s ease;
}
.nav__links a:hover {
  color: var(--text);
}
.nav__login {
  font-weight: 600 !important;
  color: var(--text) !important;
}
.nav__links .btn {
  color: #fff;
}
.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}
.nav__toggle span {
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

/* ── Hero ── */
.hero {
  position: relative;
  overflow: hidden;
  padding: 84px 0 40px;
  background: radial-gradient(
      1100px 460px at 50% -8%,
      rgba(37, 99, 235, 0.12),
      transparent 70%
    ),
    var(--bg);
}
.hero__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}
.hero__title {
  font-size: clamp(2.1rem, 5.2vw, 3.4rem);
  font-weight: 800;
  margin: 20px 0 0;
}
.grad {
  background: linear-gradient(120deg, var(--primary), #7c3aed);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero__sub {
  max-width: 640px;
  margin: 20px 0 0;
  color: var(--text-muted);
  font-size: 1.08rem;
}
.hero__cta {
  display: flex;
  gap: 14px;
  margin-top: 30px;
  flex-wrap: wrap;
  justify-content: center;
}
.hero__note {
  margin: 14px 0 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Product mock */
.hero__mock {
  width: 100%;
  max-width: 760px;
  margin: 52px auto 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  text-align: left;
}
.mock__bar {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  background: #fafbfc;
}
.mock__bar .dot {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: #e2e5ea;
}
.mock__bar .dot:nth-child(1) {
  background: #ff5f57;
}
.mock__bar .dot:nth-child(2) {
  background: #febc2e;
}
.mock__bar .dot:nth-child(3) {
  background: #28c840;
}
.mock__url {
  margin-left: 10px;
  font-size: 0.82rem;
  color: var(--text-muted);
}
.mock__body {
  padding: 22px;
  display: grid;
  gap: 16px;
}
.mock__prompt {
  background: var(--primary-soft);
  border: 1px solid rgba(37, 99, 235, 0.16);
  border-radius: var(--radius);
  padding: 16px 18px;
  font-size: 0.98rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.mock__go {
  color: var(--primary);
  font-weight: 700;
  white-space: nowrap;
  font-size: 0.9rem;
}
.mock__result {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}
.mock__result-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}
.mock__result-head strong {
  font-size: 1.05rem;
}
.tag {
  font-size: 0.74rem;
  font-weight: 700;
  color: #16a34a;
  background: rgba(22, 163, 74, 0.1);
  padding: 3px 10px;
  border-radius: 999px;
}
.mock__days {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}
.mock__days li {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.95rem;
  color: var(--text);
}
.mock__days .d {
  flex: none;
  width: 34px;
  height: 26px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--primary);
  background: var(--primary-soft);
  border-radius: 7px;
}
.mock__days .more {
  color: var(--text-muted);
  font-size: 0.88rem;
  padding-left: 46px;
}

/* ── Trust strip ── */
.strip {
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}
.strip__inner {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  padding: 28px 24px;
}
.stat {
  text-align: center;
  display: grid;
  gap: 4px;
}
.stat b {
  font-size: 1.5rem;
  color: var(--primary);
  font-weight: 800;
}
.stat span {
  font-size: 0.88rem;
  color: var(--text-muted);
}

/* ── Sections ── */
.section {
  padding: 88px 0;
}
.section--alt {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.section__head {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 48px;
  display: grid;
  gap: 14px;
  justify-items: center;
}
.section__head h2 {
  font-size: clamp(1.7rem, 3.4vw, 2.3rem);
}
.section__head p {
  margin: 0;
  color: var(--text-muted);
  font-size: 1.04rem;
}

/* ── Grid ── */
.grid {
  display: grid;
  gap: 22px;
}
.grid--3 {
  grid-template-columns: repeat(3, 1fr);
}

/* ── Feature cards ── */
.feature {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
.section--alt .feature,
.feature {
  background: var(--surface);
}
.feature:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(37, 99, 235, 0.3);
}
.feature__icon {
  font-size: 1.6rem;
  width: 52px;
  height: 52px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--primary-soft);
  border-radius: 14px;
  margin-bottom: 16px;
}
.feature h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
}
.feature p {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.96rem;
}

/* ── Steps ── */
.steps .step {
  text-align: center;
  padding: 8px;
}
.step__num {
  width: 46px;
  height: 46px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 800;
  color: #fff;
  background: var(--primary);
  border-radius: 50%;
  margin-bottom: 16px;
  box-shadow: 0 8px 18px -8px rgba(37, 99, 235, 0.7);
}
.step h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
}
.step p {
  margin: 0 auto;
  max-width: 260px;
  color: var(--text-muted);
  font-size: 0.96rem;
}

/* ── Pricing ── */
.pricing {
  align-items: stretch;
}
.plan {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 30px 26px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
}
.plan--featured {
  border-color: var(--primary);
  box-shadow: var(--shadow-lg);
  transform: translateY(-6px);
}
.plan__badge {
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary);
  color: #fff;
  font-size: 0.76rem;
  font-weight: 700;
  padding: 5px 14px;
  border-radius: 999px;
  white-space: nowrap;
}
.plan__name {
  font-size: 1.2rem;
}
.plan__price {
  margin: 14px 0 6px;
  display: flex;
  align-items: baseline;
  gap: 4px;
}
.plan__price .amt {
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}
.plan__price .per {
  color: var(--text-muted);
  font-size: 0.95rem;
}
.plan__desc {
  margin: 0 0 18px;
  color: var(--text-muted);
  font-size: 0.94rem;
}
.plan__list {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  display: grid;
  gap: 11px;
  flex: 1;
}
.plan__list li {
  position: relative;
  padding-left: 26px;
  font-size: 0.95rem;
}
.plan__list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 7px;
  width: 16px;
  height: 16px;
  background: var(--primary-soft);
  border-radius: 50%;
}
.plan__list li::after {
  content: '';
  position: absolute;
  left: 5px;
  top: 11px;
  width: 5px;
  height: 8px;
  border: solid var(--primary);
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

/* ── CTA ── */
.cta {
  padding: 80px 0;
}
.cta__inner {
  text-align: center;
  background: linear-gradient(120deg, var(--primary), #4f46e5);
  color: #fff;
  border-radius: var(--radius-lg);
  padding: 56px 24px;
  box-shadow: var(--shadow-lg);
}
.cta__inner h2 {
  font-size: clamp(1.6rem, 3.4vw, 2.2rem);
  color: #fff;
}
.cta__inner p {
  margin: 12px 0 26px;
  color: rgba(255, 255, 255, 0.88);
  font-size: 1.05rem;
}
.cta__inner .btn--primary {
  background: #fff;
  color: var(--primary);
  box-shadow: 0 10px 24px -10px rgba(0, 0, 0, 0.4);
}
.cta__inner .btn--primary:hover {
  background: #f1f5ff;
}

/* ── Footer ── */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 44px 0 28px;
}
.footer__inner {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border);
}
.footer__brand p {
  margin: 8px 0 0;
  color: var(--text-muted);
  font-size: 0.92rem;
}
.footer__nav {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}
.footer__nav a {
  color: var(--text-muted);
  font-size: 0.95rem;
  transition: color 0.15s ease;
}
.footer__nav a:hover {
  color: var(--text);
}
.footer__bottom {
  padding-top: 20px;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ── Responsive ── */
@media (max-width: 860px) {
  .grid--3 {
    grid-template-columns: 1fr 1fr;
  }
  .plan--featured {
    transform: none;
  }
}

@media (max-width: 720px) {
  .nav__toggle {
    display: flex;
  }
  .nav__links {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 14px 24px 20px;
    box-shadow: var(--shadow);
    display: none;
  }
  .nav__links.open {
    display: flex;
  }
  .nav__links a {
    padding: 10px 4px;
    font-size: 1rem;
  }
  .nav__links .btn {
    margin-top: 6px;
  }
  .strip__inner {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
  }
  .grid--3 {
    grid-template-columns: 1fr;
  }
  .section {
    padding: 64px 0;
  }
  .hero {
    padding: 56px 0 32px;
  }
}