:root {
  --bg: #ffffff;
  --surface: #ffffff;
  --surface-soft: #fafafa;
  --ink: #111111;
  --ink-soft: #5f6368;
  --line: #e5e7eb;
  --line-strong: #d7dbe0;
  --shadow: 0 8px 30px rgba(15, 23, 42, 0.06);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: "Archivo", "Segoe UI", sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
}

.topbar {
  position: sticky;
  top: 0.7rem;
  z-index: 20;
  width: min(1160px, calc(100% - 1.5rem));
  margin-inline: auto;
  padding: 0.72rem 0.84rem;
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.62rem;
  color: var(--ink);
  text-decoration: none;
}

.brand-mark {
  width: 2.25rem;
  aspect-ratio: 1;
  border-radius: 0.62rem;
  display: grid;
  place-items: center;
  font-family: "Space Mono", monospace;
  font-weight: 700;
  color: #ffffff;
  background: #111111;
}

.brand-text {
  font-weight: 800;
  letter-spacing: 0.01em;
}

.topnav {
  display: inline-flex;
  gap: 1.1rem;
  flex-wrap: wrap;
  row-gap: 0.4rem;
}

.topnav a {
  color: #4b5563;
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 700;
}

.topnav a:hover {
  color: #111111;
}

.header-actions {
  display: inline-flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.52rem;
  flex-wrap: wrap;
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 0.2rem;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 0.2rem;
  background: #ffffff;
}

.lang-option {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.3rem;
  border-radius: 999px;
  padding: 0.3rem 0.58rem;
  text-decoration: none;
  color: #6b7280;
  font-size: 0.74rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  transition: background 0.2s ease, color 0.2s ease;
}

.lang-option:hover {
  color: #111111;
  background: #f5f6f7;
}

.lang-option.is-active {
  color: #ffffff;
  background: #111111;
}

main,
.footer {
  width: min(1160px, calc(100% - 1.5rem));
  margin-inline: auto;
}

.btn {
  border: 1px solid transparent;
  border-radius: 999px;
  text-decoration: none;
  font-size: 0.86rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s ease, background 0.2s ease, color 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: #111111;
  color: #ffffff;
  padding: 0.8rem 1.28rem;
}

.btn-primary:hover {
  background: #000000;
}

.btn-outline {
  border-color: var(--line-strong);
  background: #ffffff;
  color: #111111;
  padding: 0.74rem 1.16rem;
}

.btn-outline:hover {
  border-color: #111111;
}

.btn-block {
  width: 100%;
}

.hero {
  margin-top: 1.2rem;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 0.85rem;
}

.hero-copy,
.store-panel {
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.hero-copy {
  padding: clamp(1rem, 2.7vw, 1.8rem);
}

.kicker {
  margin: 0;
  font-family: "Space Mono", monospace;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.7rem;
  color: #6b7280;
}

.hero-copy h1 {
  margin: 0.62rem 0 0.72rem;
  max-width: 16ch;
  font-size: clamp(2rem, 5vw, 3.2rem);
  line-height: 1.04;
  font-weight: 900;
}

.hero-text {
  margin: 0;
  color: var(--ink-soft);
  max-width: 62ch;
}

.hero-actions {
  margin-top: 1.14rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.62rem;
}

.hero-stats {
  margin: 1.28rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.62rem;
}

.hero-stats li {
  border: 1px solid var(--line);
  border-radius: 0.74rem;
  background: var(--surface-soft);
  padding: 0.64rem 0.68rem;
}

.hero-stats strong {
  display: block;
  font-size: 1.14rem;
  font-weight: 900;
}

.hero-stats span {
  color: #6b7280;
  font-size: 0.84rem;
}

.store-panel {
  padding: clamp(1rem, 2.7vw, 1.35rem);
}

.store-head {
  display: grid;
  grid-template-columns: 3.1rem 1fr;
  gap: 0.7rem;
  align-items: center;
}

.store-icon {
  width: 3.1rem;
  aspect-ratio: 1;
  border-radius: 0.76rem;
  display: grid;
  place-items: center;
  font-family: "Space Mono", monospace;
  font-weight: 700;
  color: #ffffff;
  background: #111111;
}

.store-head h2 {
  margin: 0;
  font-size: 1.24rem;
}

.store-head p {
  margin: 0.24rem 0 0;
  color: #6b7280;
  font-size: 0.9rem;
}

.meta-list {
  margin: 0.9rem 0 0;
  display: grid;
  gap: 0.54rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.meta-list div {
  border: 1px solid var(--line);
  border-radius: 0.66rem;
  background: var(--surface-soft);
  padding: 0.48rem 0.54rem;
}

.meta-list dt {
  margin: 0;
  color: #6b7280;
  font-size: 0.75rem;
  font-weight: 700;
}

.meta-list dd {
  margin: 0.2rem 0 0;
  font-size: 0.88rem;
  font-weight: 800;
}

.store-note {
  margin: 0.66rem 0 0;
  color: #6b7280;
  font-size: 0.8rem;
}

.store-note a {
  color: #111111;
  font-weight: 700;
}

.store-actions {
  margin-top: 0.62rem;
  display: grid;
  gap: 0.52rem;
}

.store-quick-links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.5rem;
}

.btn-mini {
  padding: 0.58rem 0.78rem;
  font-size: 0.78rem;
}

.section {
  margin-top: clamp(2rem, 5.8vw, 4.1rem);
}

.section-title h2 {
  margin: 0.46rem 0 0;
  font-size: clamp(1.42rem, 3.5vw, 2.4rem);
  line-height: 1.08;
}

.preview-layout {
  margin-top: 0.95rem;
  display: grid;
  grid-template-columns: 1fr 22rem;
  gap: 0.8rem;
}

.preview-stage {
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
  padding: 0.82rem;
  box-shadow: var(--shadow);
}

.browser-shell {
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  overflow: hidden;
  background: var(--surface-soft);
}

.browser-bar {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.54rem 0.66rem;
  border-bottom: 1px solid var(--line);
  background: #f7f7f8;
}

.browser-bar span {
  width: 0.56rem;
  aspect-ratio: 1;
  border-radius: 50%;
  background: #d2d6dc;
}

.browser-url {
  margin-left: auto;
  font-family: "Space Mono", monospace;
  font-size: 0.68rem;
  color: #6b7280;
}

.browser-canvas {
  min-height: 17rem;
  display: grid;
  grid-template-columns: 11rem 1fr;
  gap: 0.62rem;
  padding: 0.68rem;
}

.mock-sidebar,
.mock-main {
  border: 1px solid var(--line);
  border-radius: 0.66rem;
  background: #ffffff;
  padding: 0.52rem;
}

.mock-search {
  height: 1.8rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: #f5f6f7;
}

.mock-item {
  margin-top: 0.46rem;
  height: 2rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: #f8f8f9;
}

.mock-row {
  margin-top: 0.44rem;
  height: 0.9rem;
  border-radius: 999px;
  background: #eceff2;
}

.mock-row-title {
  margin-top: 0;
  height: 1.28rem;
  background: #e4e8ed;
}

.mock-row.short {
  width: 58%;
}

.mock-matrix {
  margin-top: 0.62rem;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.34rem;
}

.mock-matrix div {
  height: 4.2rem;
  border: 1px solid var(--line);
  border-radius: 0.52rem;
  background: #f7f8f9;
}

.preview-copy {
  margin-top: 0.76rem;
}

.chip {
  margin: 0;
  display: inline-flex;
  border-radius: 999px;
  padding: 0.22rem 0.54rem;
  background: #f2f3f5;
  color: #40464f;
  font-family: "Space Mono", monospace;
  font-size: 0.7rem;
}

.preview-copy h3 {
  margin: 0.6rem 0 0.42rem;
  font-size: clamp(1.18rem, 2.5vw, 1.8rem);
  line-height: 1.14;
}

.preview-copy p {
  margin: 0;
  color: var(--ink-soft);
}

.preview-copy ul {
  margin: 0.7rem 0 0;
  padding-left: 1.04rem;
  color: #3f444b;
}

.preview-nav {
  display: grid;
  gap: 0.56rem;
}

.preview-tab {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 0.82rem;
  background: var(--surface);
  text-align: left;
  cursor: pointer;
  padding: 0.68rem;
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0.56rem;
  align-items: center;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.preview-tab span {
  width: 2rem;
  aspect-ratio: 1;
  border-radius: 0.48rem;
  display: grid;
  place-items: center;
  background: #f3f4f6;
  color: #444b55;
  font-size: 0.76rem;
  font-weight: 800;
}

.preview-tab strong {
  display: block;
  font-size: 0.9rem;
  color: #111111;
}

.preview-tab small {
  color: #6b7280;
}

.preview-tab:hover {
  border-color: #a5abb3;
  transform: translateY(-1px);
}

.preview-tab.is-active {
  border-color: #111111;
}

.feature-rack {
  margin-top: 0.92rem;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.68rem;
}

.feature-rack article {
  border: 1px solid var(--line);
  border-radius: 0.84rem;
  background: var(--surface);
  padding: 0.86rem;
}

.feature-rack h3 {
  margin: 0;
  font-size: 0.99rem;
}

.feature-rack p {
  margin: 0.42rem 0 0;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.timeline {
  margin-top: 0.92rem;
  display: grid;
  gap: 0.66rem;
}

.timeline article {
  position: relative;
  border: 1px solid var(--line);
  border-radius: 0.86rem;
  background: var(--surface);
  padding: 0.9rem 0.84rem 0.9rem 1.3rem;
}

.timeline article::before {
  content: "";
  position: absolute;
  top: 0.95rem;
  left: 0.52rem;
  width: 0.38rem;
  aspect-ratio: 1;
  border-radius: 50%;
  background: #111111;
}

.version {
  margin: 0;
  display: inline-flex;
  border-radius: 999px;
  padding: 0.2rem 0.52rem;
  background: #f3f4f6;
  color: #40464f;
  font-family: "Space Mono", monospace;
  font-size: 0.72rem;
}

.timeline h3 {
  margin: 0.52rem 0 0.2rem;
  font-size: 1.02rem;
}

.timeline p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.faq-grid {
  margin-top: 0.92rem;
  display: grid;
  gap: 0.58rem;
}

.faq-grid details {
  border: 1px solid var(--line);
  border-radius: 0.82rem;
  background: var(--surface);
  padding: 0.72rem 0.8rem;
}

.faq-grid summary {
  cursor: pointer;
  color: #111111;
  font-weight: 700;
}

.faq-grid p {
  margin: 0.5rem 0 0;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.faq-grid code {
  background: #f3f4f6;
  border-radius: 0.26rem;
  padding: 0.1rem 0.28rem;
  font-family: "Space Mono", monospace;
  font-size: 0.76rem;
}

.download-panel {
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
  padding: clamp(1rem, 2.8vw, 1.45rem);
  display: grid;
  grid-template-columns: 1.04fr 0.96fr;
  gap: 0.95rem;
  align-items: center;
  box-shadow: var(--shadow);
}

.download-panel h2 {
  margin: 0.42rem 0 0.42rem;
  font-size: clamp(1.38rem, 3.5vw, 1.95rem);
}

.download-panel p {
  margin: 0;
  color: var(--ink-soft);
}

.download-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.54rem;
}

.download-actions .btn-primary {
  grid-column: 1 / -1;
}

.guide-grid {
  margin-top: 0.92rem;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.68rem;
}

.guide-card {
  border: 1px solid var(--line);
  border-radius: 0.84rem;
  background: var(--surface);
  padding: 0.9rem;
}

.guide-card h3 {
  margin: 0;
  font-size: 0.98rem;
}

.guide-steps {
  margin: 0.62rem 0 0;
  padding-left: 1.08rem;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.guide-steps li {
  margin-top: 0.32rem;
}

.guide-steps a {
  color: #111111;
  font-weight: 700;
}

.guide-steps code {
  background: #f3f4f6;
  border-radius: 0.26rem;
  padding: 0.1rem 0.28rem;
  font-family: "Space Mono", monospace;
  font-size: 0.76rem;
}

.guide-note {
  margin: 0.7rem 0 0;
  color: #6b7280;
  font-size: 0.84rem;
}

.guide-note a {
  color: #111111;
  font-weight: 700;
}

.footer {
  margin-top: 2.6rem;
  margin-bottom: 1.5rem;
  border-top: 1px solid var(--line);
  padding-top: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.7rem;
}

.footer p {
  margin: 0;
  color: #6b7280;
}

.footer a {
  color: #111111;
  font-weight: 700;
}

.footer-links {
  display: inline-flex;
  align-items: center;
  gap: 0.8rem;
}

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.56s ease, transform 0.56s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.preview-stage[data-mode="prompt"] .mock-search,
.preview-stage[data-mode="prompt"] .mock-item,
.preview-stage[data-mode="formula"] .mock-search,
.preview-stage[data-mode="formula"] .mock-item,
.preview-stage[data-mode="mermaid"] .mock-search,
.preview-stage[data-mode="mermaid"] .mock-item {
  background: #f4f5f7;
  border-color: #e1e4e8;
}

.preview-stage[data-mode="prompt"] .mock-row-title,
.preview-stage[data-mode="formula"] .mock-row-title,
.preview-stage[data-mode="mermaid"] .mock-row-title {
  background: #e3e6eb;
}

.preview-stage[data-mode="mermaid"] .mock-matrix div {
  background: #f3f4f6;
}

@media (max-width: 1080px) {
  .preview-layout {
    grid-template-columns: 1fr;
  }

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

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

@media (max-width: 860px) {
  .topbar {
    flex-wrap: wrap;
    justify-content: center;
  }

  .topnav {
    order: 3;
    width: 100%;
    justify-content: center;
  }

  .header-actions {
    justify-content: center;
    width: 100%;
  }

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

  .download-panel {
    grid-template-columns: 1fr;
  }

  .download-actions {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 660px) {
  .hero-stats {
    grid-template-columns: 1fr;
  }

  .store-quick-links {
    grid-template-columns: 1fr;
  }

  .preview-nav {
    grid-template-columns: 1fr;
  }

  .feature-rack {
    grid-template-columns: 1fr;
  }

  .browser-canvas {
    grid-template-columns: 1fr;
  }

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

  .footer-links {
    flex-wrap: wrap;
  }
}