:root {
  --bg: #fafaf9;
  --bg-soft: #f5f5f4;
  --surface: #ffffff;
  --surface-strong: #f0f9ff;
  --text: #0a0a0a;
  --text-muted: #525252;
  --text-soft: #737373;
  --border: #e7e5e4;
  --border-strong: #d6d3d1;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --success: #16a34a;
  --danger: #dc2626;
  --shadow-sm: 0 1px 2px rgba(10, 10, 10, 0.04);
  --shadow-md: 0 12px 32px rgba(10, 10, 10, 0.08);
  --radius-lg: 24px;
  --radius-md: 18px;
  --radius-sm: 12px;
  --container: 1180px;
  --font-display: "Bricolage Grotesque", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
  --font-body: "Plus Jakarta Sans", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
  --font-mono: "Geist Mono", "SFMono-Regular", "Menlo", monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
}

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

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

button {
  font: inherit;
}

.site-shell {
  min-height: 100vh;
}

.container {
  width: min(calc(100% - 32px), var(--container));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(18px);
  background: rgba(250, 250, 249, 0.84);
  border-bottom: 1px solid rgba(214, 211, 209, 0.7);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 16px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.brand img {
  width: 40px;
  height: 40px;
  border-radius: 12px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.nav a {
  padding: 10px 14px;
  border-radius: 999px;
  color: var(--text-muted);
  transition: 0.2s ease;
}

.nav a:hover,
.nav a.is-active {
  color: var(--text);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 88px 0 64px;
  border-bottom: 1px solid var(--border);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(37, 99, 235, 0.06), transparent 42%),
    linear-gradient(90deg, rgba(231, 229, 228, 0.75) 1px, transparent 1px),
    linear-gradient(rgba(231, 229, 228, 0.75) 1px, transparent 1px);
  background-size: auto, 64px 64px, 64px 64px;
  mask-image: radial-gradient(circle at top center, black 36%, transparent 88%);
  pointer-events: none;
}

.hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 28px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  width: fit-content;
  padding: 8px 14px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.9rem;
  box-shadow: var(--shadow-sm);
}

.eyebrow__dot {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: var(--success);
}

.hero h1,
.page-hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2.7rem, 8vw, 5rem);
  line-height: 0.95;
  letter-spacing: -0.05em;
}

.hero h1 span,
.accent-text {
  color: var(--accent);
}

.hero__slogan {
  margin: 0;
  font-size: clamp(1.1rem, 2.2vw, 1.4rem);
  color: var(--text-muted);
}

.hero__meta {
  margin: 0;
  max-width: 760px;
  font-size: 1.05rem;
  color: var(--text-muted);
}

.hero__cta,
.button-row {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 0 20px;
  border: 1px solid transparent;
  border-radius: 999px;
  cursor: pointer;
  font-weight: 600;
  transition: 0.2s ease;
}

.btn--primary {
  color: #ffffff;
  background: var(--text);
}

.btn--primary:hover {
  background: var(--accent);
  transform: translateY(-1px);
}

.btn--secondary {
  color: var(--text);
  background: var(--surface);
  border-color: var(--border-strong);
}

.btn--secondary:hover {
  border-color: var(--text);
}

.hero__trust {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.hero__trust span,
.mini-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.92rem;
}

.hero__contact,
.support-inline {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  color: var(--text-muted);
}

.contact-code {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-radius: 999px;
  background: #111827;
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 0.95rem;
}

.section {
  padding: 72px 0;
  border-bottom: 1px solid var(--border);
}

.section--soft {
  background: var(--bg-soft);
}

.section__header {
  margin-bottom: 34px;
}

.section__kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-soft);
}

.section__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.8rem);
  letter-spacing: -0.04em;
  line-height: 1.02;
}

.section__desc {
  margin: 12px 0 0;
  max-width: 760px;
  color: var(--text-muted);
}

.category-grid,
.card-grid,
.article-grid,
.review-grid {
  display: grid;
  gap: 20px;
}

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

.card-grid--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

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

.review-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card,
.category-card,
.article-card,
.review-card,
.support-card,
.content-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.category-card,
.article-card,
.review-card,
.content-card {
  overflow: hidden;
}

.category-card {
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: 28px 24px 24px;
  position: relative;
}

.category-card::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 4px;
}

.category-card--chatgpt::before,
.category-card--grok::before {
  background: #111111;
}

.category-card--gemini::before {
  background: linear-gradient(90deg, #3186ff 0%, #08b962 33%, #fabc12 66%, #f94543 100%);
}

.category-card--claude::before {
  background: #d97757;
}

.category-card:hover,
.article-card:hover,
.review-card:hover,
.content-card:hover,
.support-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  transition: 0.25s ease;
}

.category-card__brand {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-soft);
}

.category-card__name {
  margin: 4px 0 8px;
  font-family: var(--font-display);
  font-size: 1.55rem;
  letter-spacing: -0.03em;
}

.category-card__variants,
.category-card__features li,
.article-card__desc,
.content-card__body,
.support-card__desc {
  color: var(--text-muted);
}

.price-line {
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 14px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.price-line__currency,
.price-line__amount {
  font-family: var(--font-mono);
}

.price-line__amount {
  font-size: 2.3rem;
  font-weight: 700;
  letter-spacing: -0.04em;
}

.category-card__features {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.category-card__features li::before {
  content: "•";
  color: var(--accent);
  margin-right: 8px;
}

.category-card__link {
  font-weight: 600;
  color: var(--accent);
}

.info-callout {
  padding: 28px;
  border-radius: var(--radius-lg);
  background: var(--surface);
  border: 1px solid var(--border);
}

.info-callout strong {
  color: var(--text);
}

.article-card__body,
.content-card__body,
.support-card {
  padding: 28px;
}

.article-card__meta {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.tag {
  display: inline-flex;
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--surface-strong);
  color: var(--accent);
  font-size: 0.84rem;
  font-weight: 600;
}

.article-card h3,
.feature-card h3,
.support-card h3,
.content-card h2,
.content-card h3,
.faq-list h3 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  letter-spacing: -0.03em;
}

.feature-card {
  padding: 28px;
}

.feature-card p {
  margin: 0;
  color: var(--text-muted);
}

.review-card img {
  width: 100%;
  aspect-ratio: 4 / 5;
  object-fit: cover;
}

.trust-layout {
  display: grid;
  grid-template-columns: minmax(0, 2fr) minmax(320px, 1fr);
  gap: 24px;
}

.steps {
  display: grid;
  gap: 18px;
}

.step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 18px;
  align-items: start;
}

.step__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: 18px;
  background: #111827;
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
}

.step h3,
.support-card h3,
.page-hero h1 {
  margin: 0 0 10px;
}

.promise-list {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 22px;
}

.support-card {
  height: fit-content;
}

.support-card__code {
  display: inline-flex;
  width: 100%;
  justify-content: center;
  padding: 14px 18px;
  border-radius: 16px;
  background: #111827;
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 1rem;
  margin: 18px 0;
}

.site-footer {
  padding: 48px 0;
  background: #111827;
  color: rgba(255, 255, 255, 0.9);
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 24px;
}

.site-footer h4 {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: 1rem;
}

.site-footer p,
.site-footer li,
.site-footer a {
  color: rgba(255, 255, 255, 0.72);
}

.site-footer ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 10px;
}

.page-hero {
  padding: 72px 0 42px;
  border-bottom: 1px solid var(--border);
}

.page-hero p {
  max-width: 720px;
  margin: 14px 0 0;
  color: var(--text-muted);
}

.prose {
  display: grid;
  gap: 22px;
}

.prose p,
.prose li {
  color: var(--text-muted);
}

.prose ul,
.prose ol {
  margin: 0;
  padding-left: 22px;
}

.prose blockquote {
  margin: 0;
  padding: 18px 22px;
  border-left: 4px solid var(--accent);
  background: #eff6ff;
  border-radius: 0 16px 16px 0;
  color: var(--text);
}

.split-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.faq-list {
  display: grid;
  gap: 14px;
}

.faq-list details {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.faq-list summary {
  cursor: pointer;
  font-weight: 700;
  list-style: none;
}

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

.faq-list p {
  margin: 14px 0 0;
  color: var(--text-muted);
}

.pill-list {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.note {
  padding: 16px 18px;
  border-radius: 16px;
  background: #eff6ff;
  color: var(--text-muted);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

@media (max-width: 1080px) {
  .category-grid,
  .site-footer__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .card-grid--3,
  .review-grid,
  .trust-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 760px) {
  .site-header__inner,
  .nav,
  .hero__cta,
  .button-row,
  .hero__contact,
  .support-inline {
    align-items: flex-start;
  }

  .nav {
    justify-content: flex-start;
  }

  .category-grid,
  .article-grid,
  .split-list,
  .site-footer__grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 64px;
  }

  .step {
    grid-template-columns: 1fr;
  }
}