/* Tokens */

:root {
  --color-ground: #0b0d10;
  --color-ground-raised: #0e1013;
  --color-line: #1e2127;
  --color-line-strong: #2a2f36;
  --color-line-pill: #262a31;
  --color-muted-strong: #4a505a;
  --color-ink: #f3f5f7;
  --color-ink-soft: #c4cad3;
  --color-ink-sub: #b4bcc8;
  --color-ink-muted: #9aa3b2;
  --color-ink-faint: #6b7483;
  --color-accent: #d0dfb0;
  --color-accent-ink: #182010;
  --color-accent-glow: #d0dfb029;
  --color-accent-wash: #d0dfb024;

  --font-sans: "Inter", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;

  --tracking-display: -0.045em;
  --tracking-title: -0.04em;
  --tracking-heading: -0.02em;
  --tracking-label: 0.08em;
  --tracking-eyebrow: 0.1em;

  --gutter: 80px;
  --content: 1280px;
}

:root:lang(zh-Hant) {
  --font-sans: "Noto Sans TC", "Inter", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", "Noto Sans TC", ui-monospace, monospace;
  --tracking-display: 0;
  --tracking-title: 0;
  --tracking-heading: 0;
}

/* Base */

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

html {
  background: var(--color-ground);
  color-scheme: dark;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-ink);
  background: var(--color-ground);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-synthesis: none;
}

h1,
h2,
h3,
p,
ol,
ul,
figure {
  margin: 0;
  padding: 0;
}

ol,
ul {
  list-style: none;
}

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

a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 4px;
  border-radius: 4px;
}

.latin {
  font-family: "Inter", system-ui, sans-serif;
}

.container {
  width: 100%;
  max-width: calc(var(--content) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  border-top: 1px solid var(--color-line);
}

.eyebrow {
  font-family: var(--font-mono);
  font-weight: 400;
  font-size: 13px;
  line-height: 16px;
  letter-spacing: var(--tracking-eyebrow);
  color: var(--color-accent);
}

.accent {
  color: var(--color-accent);
}

/* Brand */

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-mark {
  flex-shrink: 0;
  fill: var(--color-accent);
}

.brand-name {
  font-family: "Inter", system-ui, sans-serif;
  font-weight: 700;
  font-size: 18px;
  line-height: 22px;
  letter-spacing: -0.01em;
}

/* Header */

.site-header {
  border-bottom: 1px solid var(--color-line);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 24px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 36px;
  font-size: 14px;
  line-height: 18px;
  color: var(--color-ink-muted);
}

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

.lang-switch {
  padding: 7px 14px;
  border: 1px solid var(--color-line-strong);
  border-radius: 99px;
  font-family: "Inter", "Noto Sans TC", system-ui, sans-serif;
  color: var(--color-ink);
}

.lang-switch:hover {
  border-color: var(--color-muted-strong);
}

/* Hero */

.hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 28px;
  padding: 96px var(--gutter) 64px;
  text-align: center;
}

.badge {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 14px;
  border: 1px solid var(--color-line-pill);
  border-radius: 99px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 16px;
  letter-spacing: var(--tracking-label);
  color: var(--color-ink-muted);
}

.dot {
  flex-shrink: 0;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-accent);
}

.hero-title {
  display: flex;
  flex-direction: column;
  font-weight: 700;
  font-size: 88px;
  line-height: 90px;
  letter-spacing: var(--tracking-display);
}

.hero-sub {
  max-width: 560px;
  font-weight: 300;
  font-size: 19px;
  line-height: 30px;
  color: var(--color-ink-sub);
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 15px 26px;
  border-radius: 99px;
  background: var(--color-accent);
  color: var(--color-accent-ink);
  font-weight: 600;
  font-size: 15px;
  line-height: 18px;
  transition: filter 120ms ease;
}

.button:hover {
  filter: brightness(1.06);
}

/* Laptop stage */

.stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 8px var(--gutter) 140px;
}

.lid {
  display: flex;
  width: 100%;
  max-width: 1120px;
  padding: 14px;
  background: #1a1c20;
  border: 1px solid #34383f;
  border-radius: 24px 24px 6px 6px;
  box-shadow:
    #000000f2 0 50px 120px -30px,
    #d0dfb038 0 0 160px -20px;
}

.screen {
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 664px;
  overflow: hidden;
  border-radius: 10px;
  background: #212121;
  text-align: left;
}

.base {
  display: flex;
  justify-content: center;
  flex-shrink: 0;
  width: calc(100% + 2 * min(90px, var(--gutter)));
  max-width: 1300px;
  height: 20px;
  border-radius: 2px 2px 20px 20px;
  background-image: linear-gradient(in oklab 180deg, oklab(36.3% -0.002 -0.013) 0%, oklab(23.5% -0.0008 -0.008) 60%, oklab(18.7% 0.0001 -0.006) 100%);
}

.base::before {
  content: "";
  width: 180px;
  height: 7px;
  border-radius: 0 0 8px 8px;
  background: #15171a;
}

/* ChatGPT window inside the stage */

.titlebar {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  height: 38px;
  padding-inline: 14px;
  background: #181818;
  border-bottom: 1px solid #2a2a2a;
}

.titlebar-lights,
.titlebar-spacer {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
  width: 200px;
}

.titlebar-lights span {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.titlebar-lights span:nth-child(1) {
  background: #ff5f57;
}

.titlebar-lights span:nth-child(2) {
  background: #febc2e;
}

.titlebar-lights span:nth-child(3) {
  background: #28c840;
}

.titlebar-title {
  flex: 1 1 0;
  text-align: center;
  font-family: "Inter", system-ui, sans-serif;
  font-weight: 600;
  font-size: 13px;
  line-height: 16px;
  color: #ececec;
}

.app {
  display: flex;
  flex: 1 1 0;
  min-height: 0;
}

.chat-sidebar {
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  gap: 4px;
  width: 190px;
  padding: 14px 10px;
  background: #171717;
  font-size: 13px;
  line-height: 16px;
  color: #b4b4b4;
}

.chat-sidebar li {
  padding: 8px 10px;
  border-radius: 8px;
}

.chat-sidebar .is-new {
  display: flex;
  gap: 8px;
  color: #ececec;
}

.chat-sidebar .is-active {
  background: #2a2a2a;
  color: #ececec;
}

.chat-sidebar .group {
  padding: 14px 10px 6px;
  font-weight: 600;
  font-size: 11px;
  line-height: 14px;
  color: #8e8e8e;
}

.chat-main {
  display: flex;
  flex-direction: column;
  flex: 1 1 0;
  min-width: 0;
  gap: 20px;
  padding: 28px 28px 18px;
  background: #212121;
  font-size: 13px;
  color: #ececec;
}

.bubble {
  align-self: flex-end;
  width: 300px;
  max-width: 100%;
  padding: 12px 16px;
  border-radius: 18px;
  background: #303030;
  line-height: 20px;
}

.reply {
  display: flex;
  flex-direction: column;
  gap: 12px;
  line-height: 21px;
}

.attachment {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 250px;
  padding: 10px 12px;
  border-radius: 12px;
  background: #262626;
  border: 1px solid #3a3a3a;
}

.attachment-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--color-accent-wash);
}

.attachment-text {
  display: flex;
  flex-direction: column;
}

.attachment-text strong {
  font-family: "Inter", system-ui, sans-serif;
  font-weight: 600;
  font-size: 12px;
  line-height: 16px;
}

.attachment-text span {
  font-size: 11px;
  line-height: 14px;
  color: #8e8e8e;
}

.composer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding: 12px 16px;
  border-radius: 24px;
  background: #303030;
  line-height: 16px;
  color: #8e8e8e;
}

.composer::after {
  content: "";
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: #ececec;
}

/* Ghoster thread editor inside the stage */

.editor {
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  width: 420px;
  background: #111418;
  border-left: 1px solid var(--color-line-strong);
}

.editor-head,
.editor-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
}

.editor-head {
  border-bottom: 1px solid var(--color-line);
}

.editor-foot {
  padding-block: 12px;
  margin-top: auto;
  border-top: 1px solid var(--color-line);
  font-size: 12px;
  line-height: 16px;
  color: var(--color-ink-muted);
}

.editor-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  line-height: 16px;
  color: var(--color-ink-faint);
}

.editor-title strong {
  font-family: "Inter", system-ui, sans-serif;
  font-weight: 600;
  color: var(--color-ink);
}

.chip {
  padding: 4px 10px;
  border-radius: 99px;
  background: #1c2026;
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 14px;
  color: var(--color-ink-muted);
}

.posts {
  display: flex;
  flex-direction: column;
  padding: 20px 24px 0;
}

.post {
  display: flex;
  gap: 14px;
}

.post-rail {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-shrink: 0;
  width: 22px;
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 12px;
  line-height: 24px;
  color: var(--color-ink-faint);
}

.post-rail::after {
  content: "";
  flex: 1 1 0;
  width: 1px;
  background: var(--color-line-strong);
}

.post:last-child .post-rail::after {
  background: transparent;
}

.post-body {
  display: flex;
  flex-direction: column;
  flex: 1 1 0;
  gap: 10px;
  padding-bottom: 22px;
}

.post-body p {
  font-size: 14px;
  line-height: 22px;
  color: var(--color-ink);
}

.post-meta {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 16px;
  color: var(--color-ink-faint);
}

.pill-button {
  padding: 7px 14px;
  border-radius: 99px;
  background: var(--color-accent);
  font-weight: 600;
  color: var(--color-accent-ink);
}

/* Today: the five-step flow */

.today .container {
  display: flex;
  flex-direction: column;
  gap: 48px;
  padding-block: 112px;
}

.steps {
  display: flex;
  gap: 32px;
}

.step {
  display: flex;
  flex-direction: column;
  flex: 1 1 0;
  gap: 12px;
  padding-top: 20px;
  border-top: 1px solid var(--color-line-strong);
}

.step-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 13px;
  line-height: 16px;
  letter-spacing: var(--tracking-label);
  color: var(--color-ink-faint);
}

.step-head::after {
  content: "\2192";
  font-family: "Inter", system-ui, sans-serif;
  font-size: 16px;
  letter-spacing: 0;
  color: var(--color-muted-strong);
}

.step h3 {
  font-weight: 700;
  font-size: 28px;
  line-height: 32px;
  letter-spacing: var(--tracking-heading);
}

.step p {
  line-height: 25px;
  color: var(--color-ink-muted);
}

.step:last-child {
  border-top-color: var(--color-accent);
}

.step:last-child .step-head,
.step:last-child h3 {
  color: var(--color-accent);
}

.step:last-child .step-head::after {
  content: none;
}

/* Roadmap */

.roadmap {
  background: var(--color-ground-raised);
}

.roadmap .container {
  display: flex;
  flex-direction: column;
  gap: 72px;
  padding-block: 120px;
}

.roadmap-intro {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 40px;
}

.roadmap-heading {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.roadmap-heading h2 {
  max-width: 800px;
  font-weight: 700;
  font-size: 64px;
  line-height: 66px;
  letter-spacing: var(--tracking-title);
}

:lang(zh-Hant) .roadmap-heading h2 {
  max-width: 880px;
  font-size: 56px;
}

.roadmap-note {
  flex-shrink: 0;
  width: 300px;
  text-align: right;
  font-size: 15px;
  line-height: 24px;
  color: var(--color-ink-faint);
}

.timeline {
  position: relative;
  display: flex;
  gap: 48px;
}

.timeline::before {
  content: "";
  position: absolute;
  top: 9px;
  inset-inline: 0;
  height: 1px;
  background-image: linear-gradient(in oklab 90deg, oklab(88% -0.034 0.055) 0%, oklab(88% -0.034 0.055) 30%, oklab(30.3% -0.003 -0.014) 36%, oklab(30.3% -0.003 -0.014) 100%);
}

.stage-item {
  position: relative;
  display: flex;
  flex-direction: column;
  flex: 1 1 0;
  gap: 22px;
}

.stage-dot {
  flex-shrink: 0;
  width: 19px;
  height: 19px;
  border-radius: 50%;
  background: var(--color-ground-raised);
  border: 2px solid var(--color-muted-strong);
}

.stage-tag {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-top: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 16px;
  letter-spacing: var(--tracking-label);
  color: var(--color-ink-muted);
}

.version {
  padding: 2px 9px;
  border-radius: 99px;
  border: 1px solid var(--color-muted-strong);
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-weight: 600;
  letter-spacing: 0;
  color: var(--color-ink);
}

.stage-item h3 {
  font-weight: 700;
  font-size: 28px;
  line-height: 32px;
  letter-spacing: var(--tracking-heading);
}

.stage-item ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
  line-height: 24px;
  color: var(--color-ink-muted);
}

.stage-item.is-now .stage-dot {
  background: var(--color-accent);
  border: 0;
  box-shadow: var(--color-accent-glow) 0 0 0 6px;
}

.stage-item.is-now .stage-tag {
  color: var(--color-accent);
}

.stage-item.is-now .version {
  padding: 3px 10px;
  border: 0;
  background: var(--color-accent);
  color: var(--color-accent-ink);
}

.stage-item.is-now ul {
  color: var(--color-ink-soft);
}

.stage-item.is-later .stage-dot,
.stage-item.is-later .version {
  border-style: dashed;
}

/* Trust strip */

.trust {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px 56px;
  padding: 36px var(--gutter);
  line-height: 20px;
  color: var(--color-ink-soft);
}

.trust li {
  display: flex;
  align-items: center;
  gap: 10px;
}

.trust li::before {
  content: "";
  flex-shrink: 0;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
}

/* Footer */

.site-footer .container {
  display: flex;
  flex-direction: column;
  gap: 72px;
  padding-block: 120px 56px;
}

.closing {
  display: flex;
  flex-direction: column;
  font-weight: 700;
  font-size: 64px;
  line-height: 68px;
  letter-spacing: var(--tracking-title);
}

.footer-meta {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 40px;
  padding-top: 28px;
  border-top: 1px solid var(--color-line);
}

.footer-brand .brand-name {
  font-weight: 600;
  font-size: 15px;
  line-height: 18px;
  letter-spacing: 0;
}

.footer-brand small {
  padding-left: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 16px;
  color: var(--color-ink-faint);
}

.disclaimer {
  max-width: 520px;
  text-align: right;
  font-size: 13px;
  line-height: 20px;
  color: var(--color-ink-faint);
}

/* Responsive */

@media (max-width: 1180px) {
  :root {
    --gutter: 48px;
  }

  .hero-title {
    font-size: 72px;
    line-height: 76px;
  }

  .chat-sidebar {
    display: none;
  }

  .steps {
    flex-wrap: wrap;
    row-gap: 48px;
  }

  .step {
    flex: 1 1 calc((100% - 64px) / 3);
  }
}

@media (max-width: 860px) {
  :root {
    --gutter: 24px;
  }

  .nav {
    gap: 20px;
  }

  .nav a:not(.lang-switch) {
    display: none;
  }

  .hero {
    padding-block: 64px 48px;
  }

  .hero-title {
    font-size: 48px;
    line-height: 52px;
  }

  .hero-sub {
    font-size: 17px;
    line-height: 27px;
  }

  .stage {
    padding-bottom: 96px;
  }

  .screen {
    height: auto;
  }

  .app {
    flex: none;
  }

  .chat-main,
  .titlebar-spacer {
    display: none;
  }

  .titlebar-lights {
    width: auto;
  }

  .titlebar-title {
    padding-right: 52px;
  }

  .editor {
    width: 100%;
    border-left: 0;
  }

  .today .container {
    padding-block: 80px;
  }

  .step {
    flex-basis: calc((100% - 32px) / 2);
  }

  .roadmap .container {
    gap: 56px;
    padding-block: 88px;
  }

  .roadmap-intro {
    flex-direction: column;
    align-items: flex-start;
    gap: 20px;
  }

  .roadmap-heading h2,
  :lang(zh-Hant) .roadmap-heading h2 {
    font-size: 44px;
    line-height: 48px;
  }

  .roadmap-note {
    width: auto;
    text-align: left;
  }

  .timeline {
    flex-direction: column;
    gap: 48px;
  }

  .timeline::before {
    top: 0;
    bottom: 0;
    left: 9px;
    right: auto;
    width: 1px;
    height: auto;
    background-image: linear-gradient(in oklab 180deg, oklab(88% -0.034 0.055) 0%, oklab(88% -0.034 0.055) 30%, oklab(30.3% -0.003 -0.014) 36%, oklab(30.3% -0.003 -0.014) 100%);
  }

  .stage-item {
    padding-left: 40px;
  }

  .stage-dot {
    position: absolute;
    top: 0;
    left: 0;
  }

  .stage-tag {
    padding-top: 0;
  }

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

  .site-footer .container {
    gap: 56px;
    padding-top: 88px;
  }

  .closing {
    font-size: 44px;
    line-height: 50px;
  }

  .footer-meta {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  .disclaimer {
    text-align: left;
  }
}

@media (max-width: 520px) {
  .hero-title {
    font-size: 40px;
    line-height: 44px;
  }

  .step {
    flex-basis: 100%;
  }

  .closing {
    font-size: 36px;
    line-height: 42px;
  }
}