/* Mermaid Workbench landing — editorial paper studio
   Warm ivory + ink. Serif display. One black CTA. No neon, no grid. */

:root {
  --paper: #f3efe6;
  --paper-2: #ebe6db;
  --ink: #1c1915;
  --ink-soft: #3f3a34;
  --mute: #6f6860;
  --line: #d8d0c3;
  --line-strong: #c4bbad;
  --card: #faf7f1;
  --shadow: 0 24px 60px rgba(28, 25, 21, 0.08);
  --radius: 2px;
  --font-serif: "Fraunces", "Noto Serif SC", "Songti SC", serif;
  --font-sans: "IBM Plex Sans", "Noto Sans SC", "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", "Consolas", monospace;
  --max: 1180px;
  --header-h: 72px;
}

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

html[data-locale="zh"] body {
  line-height: 1.7;
}

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

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

.container {
  width: min(100% - 3rem, var(--max));
  margin-inline: auto;
}

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

/* ——— Header ——— */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--line);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  width: min(100% - 3rem, var(--max));
  margin-inline: auto;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.55rem;
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: 1.12rem;
  letter-spacing: -0.02em;
}

.brand__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--ink);
  transform: translateY(-1px);
}

.nav {
  display: flex;
  align-items: center;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.6rem;
}

.nav-links a {
  font-size: 0.92rem;
  color: var(--mute);
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--ink);
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.82rem;
  letter-spacing: 0.04em;
}

.lang-switch__btn {
  appearance: none;
  border: 0;
  padding: 0;
  background: none;
  font-family: inherit;
  font-size: inherit;
  color: var(--mute);
  cursor: pointer;
}

.lang-switch__btn.is-active {
  color: var(--ink);
  font-weight: 600;
}

.lang-switch__btn:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 3px;
}

.lang-switch__rule {
  color: var(--line-strong);
}

.nav__cta {
  display: inline-flex;
  align-items: center;
  padding: 0.48rem 0.95rem;
  background: var(--ink);
  color: var(--paper) !important;
  font-size: 0.88rem;
  font-weight: 500;
  border-radius: var(--radius);
}

.nav__cta:hover {
  background: var(--ink-soft);
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--line-strong);
  color: var(--ink);
  width: 40px;
  height: 40px;
  cursor: pointer;
}

/* ——— Buttons ——— */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.95rem 1.55rem;
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-weight: 500;
  font-size: 1.02rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}

.btn:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 3px;
}

.btn--ink {
  background: var(--ink);
  color: var(--paper);
}

.btn--ink:hover {
  background: var(--ink-soft);
}

/* ——— Hero ——— */
.hero {
  padding: 5.5rem 0 4rem;
  text-align: center;
}

.hero__kicker {
  margin: 0 0 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mute);
}

.hero h1 {
  margin: 0 auto 1.25rem;
  max-width: 16ch;
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: clamp(2.4rem, 6vw, 4.35rem);
  line-height: 1.12;
  letter-spacing: -0.03em;
}

html[data-locale="zh"] .hero h1 {
  max-width: 12em;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.hero__sub {
  margin: 0 auto 2rem;
  max-width: 38rem;
  color: var(--mute);
  font-size: 1.12rem;
}

.hero__actions {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.85rem;
}

.hero__micro {
  margin: 0;
  font-size: 0.88rem;
  color: var(--mute);
}

.hero__stage {
  width: min(100% - 3rem, 1080px);
  margin: 3.25rem auto 0;
}

.demo-frame {
  position: relative;
  background: var(--card);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.demo-frame video {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  object-position: center top;
  background: #e8e2d6;
}

.demo-caption {
  margin: 0.85rem 0 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--mute);
  text-align: center;
}

/* ——— Capability blocks ——— */
.capabilities {
  padding: 2rem 0 5rem;
}

.cap-kicker {
  margin: 0 0 3.5rem;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mute);
}

.cap {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.15fr);
  gap: 3.5rem;
  align-items: center;
  padding: 3.5rem 0;
  border-top: 1px solid var(--line);
}

.cap--flip {
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.9fr);
}

.cap--flip .cap__copy {
  order: 2;
}

.cap__num {
  margin: 0 0 0.65rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: var(--mute);
}

.cap h2 {
  margin: 0 0 0.9rem;
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: clamp(1.85rem, 3vw, 2.55rem);
  letter-spacing: -0.03em;
  line-height: 1.18;
}

.cap p {
  margin: 0;
  color: var(--mute);
  max-width: 36em;
}

.cap__badge {
  display: inline-block;
  margin-top: 1rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
  border: 1px solid var(--line-strong);
  padding: 0.25rem 0.5rem;
}

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 1px solid var(--line);
  background: var(--card);
  min-height: 280px;
}

.split__pane {
  padding: 1rem 1rem 0.85rem;
  min-width: 0;
}

.split__pane + .split__pane {
  border-left: 1px solid var(--line);
}

.split__label {
  margin: 0 0 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mute);
}

.split svg {
  width: 100%;
  height: auto;
}

.split__code {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.55;
  color: var(--ink-soft);
  margin: 0;
  white-space: pre-wrap;
}

.split__code .kw {
  color: var(--ink);
  font-weight: 600;
}

/* ——— Gallery ——— */
.gallery {
  padding: 4.5rem 0 5.5rem;
  border-top: 1px solid var(--line);
  background: var(--paper-2);
}

.gallery__head {
  max-width: 34rem;
  margin-bottom: 2.5rem;
}

.gallery__head .kicker {
  margin: 0 0 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mute);
}

.gallery__head h2 {
  margin: 0 0 0.75rem;
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: clamp(1.9rem, 3.2vw, 2.7rem);
  letter-spacing: -0.03em;
}

.gallery__head p {
  margin: 0;
  color: var(--mute);
}

.gallery-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.15rem;
}

.g-card {
  background: var(--card);
  border: 1px solid var(--line);
  padding: 1.1rem 1.1rem 1rem;
}

.g-card svg {
  width: 100%;
  height: auto;
}

.g-card h3 {
  margin: 1rem 0 0.2rem;
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 500;
}

.g-card p {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--mute);
}

/* ——— Footer ——— */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 1.6rem 0 2.4rem;
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: space-between;
  align-items: center;
  color: var(--mute);
  font-size: 0.88rem;
}

.site-footer__links {
  display: flex;
  gap: 1.25rem;
}

.site-footer a:hover {
  color: var(--ink);
}

/* Reveal */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

@media (max-width: 960px) {
  .cap,
  .cap--flip {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .cap--flip .cap__copy {
    order: 0;
  }

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

@media (max-width: 720px) {
  .nav-toggle {
    display: grid;
    place-items: center;
  }

  .nav-links {
    display: none;
  }

  .nav.is-open .nav-links {
    display: flex;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 0.75rem 1.5rem 1.1rem;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
  }

  .nav.is-open .nav-links a,
  .nav.is-open .lang-switch {
    padding: 0.7rem 0;
  }

  .hero {
    padding-top: 3.2rem;
  }

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

  .split__pane + .split__pane {
    border-left: 0;
    border-top: 1px solid var(--line);
  }
}