/* ==========================================================================
   BiWrite mainpage
   "manuscript & marginalia": warm paper, iron-gall ink, vermilion seal.
   ========================================================================== */

:root {
  color-scheme: light;
  --paper: #f7f2e8;
  --paper-2: #f0e9db;
  --paper-3: #e9e0cf;
  --paper-rgb: 247, 242, 232;
  --ink: #23252c;
  --ink-soft: #3c3f48;
  --muted: #6d685f;
  --faint: #6d685f;
  --rule: #d9d0be;
  --rule-strong: #c3b8a2;
  --accent: #2b4a8b;
  --accent-ink: #203a70;
  --accent-wash: rgba(43, 74, 139, 0.08);
  --accent-soft: rgba(43, 74, 139, 0.34);
  --seal: #b8432f;
  --seal-ink: #96311f;
  --seal-wash: rgba(184, 67, 47, 0.09);
  --navy: #1e2a4a;
  --navy-deep: #161f35;
  --cream: #f3ecde;
  --cream-dim: rgba(243, 236, 222, 0.68);
  --serif: "Iowan Old Style", "Charter", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
  --serif-zh: "Iowan Old Style", "Charter", "Songti SC", STSong, "Source Han Serif SC", "Noto Serif CJK SC", "Songti TC", "SimSun", Georgia, serif;
  --sans: "Avenir Next", Avenir, "Helvetica Neue", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --sans-zh: "Avenir Next", Avenir, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", "Helvetica Neue", sans-serif;
  --mono: "SF Mono", "JetBrains Mono", "Cascadia Mono", Menlo, Consolas, "PingFang SC", monospace;
  --max: 1220px;
  --gutter: clamp(20px, 5vw, 48px);
  --section-y: clamp(64px, 7.5vw, 104px);
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 92px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17.5px;
  line-height: 1.65;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

html[data-lang="zh"] body {
  font-family: var(--serif-zh);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: 0.01em;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 100;
  pointer-events: none;
  opacity: 0.045;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.82' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.7'/%3E%3C/svg%3E");
}

::selection {
  background: var(--seal);
  color: var(--cream);
}

img {
  max-width: 100%;
}

h1,
h2,
h3,
h4 {
  font-weight: 500;
  text-wrap: balance;
}

p {
  text-wrap: pretty;
}

a {
  color: inherit;
}

button {
  font: inherit;
}

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

:where(.btn-primary, .dl-btn, .plate-button):focus-visible {
  outline-color: var(--seal);
}

.method :focus-visible,
.site-footer :focus-visible {
  outline-color: var(--cream);
}

/* Language switching ------------------------------------------------------- */
html[data-lang="en"] .lang-zh,
html[data-lang="zh"] .lang-en {
  display: none !important;
}

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

.sprite {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 300;
  transform: translateY(-180%);
  background: var(--ink);
  color: var(--cream);
  padding: 10px 16px;
  font-family: var(--sans);
  font-size: 12px;
  text-decoration: none;
  transition: transform 0.2s var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
}

.kicker {
  margin: 0;
  font-family: var(--mono);
  font-size: 10.5px;
  font-weight: 500;
  line-height: 1.55;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

html[data-lang="zh"] .kicker {
  letter-spacing: 0.12em;
  font-size: 11px;
}

.inline-link {
  color: var(--accent-ink);
  text-decoration: none;
  border-bottom: 1px solid rgba(43, 74, 139, 0.35);
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease);
}

.inline-link:hover {
  color: var(--seal-ink);
  border-color: var(--seal);
}

code {
  font-family: var(--mono);
  font-size: 0.82em;
  letter-spacing: -0.01em;
  color: var(--accent-ink);
  background: rgba(35, 37, 44, 0.055);
  padding: 0.1em 0.32em;
  border-radius: 2px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border: 1px solid transparent;
  border-radius: 2px;
  padding: 14px 20px;
  font-family: var(--sans);
  font-size: 11.5px;
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0.085em;
  text-transform: uppercase;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: background 0.22s var(--ease), border-color 0.22s var(--ease), color 0.22s var(--ease),
    transform 0.22s var(--ease), box-shadow 0.22s var(--ease);
}

html[data-lang="zh"] .btn {
  font-family: var(--sans-zh);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  text-transform: none;
}

.btn-icon {
  width: 15px;
  height: 15px;
  flex: none;
}

.btn-primary {
  background: var(--seal);
  border-color: var(--seal);
  color: var(--cream);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.15), 0 1px 0 rgba(35, 37, 44, 0.06);
}

.btn-primary:hover {
  background: var(--seal-ink);
  border-color: var(--seal-ink);
  transform: translateY(-1px);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.12), 0 8px 20px -14px rgba(150, 49, 31, 0.8);
}

.btn-ghost {
  background: transparent;
  border-color: var(--rule-strong);
  color: var(--ink);
}

.btn-ghost:hover {
  border-color: var(--ink);
  background: rgba(255, 255, 255, 0.28);
  transform: translateY(-1px);
}

.btn-large {
  padding: 17px 24px;
  font-size: 12px;
}

html[data-lang="zh"] .btn-large {
  font-size: 13px;
}

.btn-small {
  padding: 9px 13px;
  font-size: 10px;
  letter-spacing: 0.1em;
}

html[data-lang="zh"] .btn-small {
  font-size: 11.5px;
}

/* Header ------------------------------------------------------------------ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(var(--paper-rgb), 0.86);
  border-bottom: 1px solid transparent;
  transition: background 0.25s var(--ease), border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
  -webkit-backdrop-filter: blur(11px) saturate(1.08);
  backdrop-filter: blur(11px) saturate(1.08);
}

.site-header.is-scrolled {
  background: rgba(var(--paper-rgb), 0.94);
  border-color: var(--rule);
  box-shadow: 0 10px 30px -30px rgba(35, 37, 44, 0.55);
}

.nav {
  display: flex;
  align-items: center;
  gap: 30px;
  height: 70px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  flex: none;
}

.brand-mark {
  width: 27px;
  height: 27px;
  display: block;
  flex: none;
}

.brand-name {
  font-family: var(--serif);
  font-size: 21px;
  font-weight: 500;
  letter-spacing: 0.005em;
  line-height: 1;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  margin-left: 8px;
}

.nav-links a {
  padding: 5px 0;
  font-family: var(--sans);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

html[data-lang="zh"] .nav-links a {
  font-family: var(--sans-zh);
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: none;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-left: auto;
}

.lang-switch {
  display: inline-flex;
  padding: 2px;
  border: 1px solid var(--rule-strong);
  background: rgba(255, 255, 255, 0.22);
}

.lang-switch button {
  padding: 6px 7px;
  border: 0;
  background: transparent;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 9.5px;
  line-height: 1;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: background 0.18s var(--ease), color 0.18s var(--ease);
}

.lang-switch button[aria-pressed="true"] {
  background: var(--ink);
  color: var(--cream);
}

.lang-switch button:hover:not([aria-pressed="true"]) {
  color: var(--ink);
}

.nav-github {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  color: var(--muted);
  transition: color 0.2s var(--ease);
}

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

.nav-github svg {
  width: 18px;
  height: 18px;
}

/* Hero -------------------------------------------------------------------- */
.hero {
  padding-top: clamp(30px, 4vw, 52px);
  padding-bottom: clamp(64px, 8vw, 108px);
}

.hero-meta {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 24px;
  padding-top: 13px;
  border-top: 1px solid var(--rule-strong);
}

.hero-meta .kicker {
  color: var(--seal-ink);
}

.hero-meta-right {
  margin: 0;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.05em;
  color: var(--muted);
  text-align: right;
  white-space: nowrap;
}

.hero-title-block {
  margin-top: clamp(38px, 5.5vw, 68px);
}

.hero-title {
  margin: 0;
  font-size: clamp(3.35rem, 8.6vw, 7.5rem);
  font-weight: 500;
  line-height: 0.94;
  letter-spacing: -0.038em;
  max-width: 14ch;
}

.hero-title .accent {
  color: var(--accent);
  font-style: italic;
  letter-spacing: -0.045em;
}

.hero-title-zh {
  font-family: var(--serif-zh);
  font-size: clamp(2.9rem, 7vw, 5.9rem);
  line-height: 1.12;
  letter-spacing: 0.015em;
  max-width: 12ch;
}

html[data-lang="zh"] .hero-title {
  letter-spacing: 0.02em;
}

.hero-title-zh .accent {
  color: var(--seal);
  font-style: normal;
  letter-spacing: 0.015em;
}

.hero-gloss {
  display: flex;
  align-items: center;
  gap: 11px;
  margin: clamp(18px, 2.2vw, 26px) 0 0;
  font-size: 16px;
  line-height: 1.5;
  color: var(--muted);
}

.hero-gloss em {
  font-style: italic;
}

html[data-lang="en"] .hero-gloss[lang="zh-CN"] {
  font-family: var(--serif-zh);
  letter-spacing: 0.05em;
}

.gloss-rule {
  display: inline-block;
  width: 30px;
  height: 1px;
  background: var(--seal);
  flex: none;
}

.hero-bottom {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  gap: clamp(36px, 5vw, 72px);
  align-items: start;
  margin-top: clamp(36px, 5vw, 54px);
}

.hero-dek {
  margin: 0;
  max-width: 55ch;
  font-size: clamp(17px, 1.45vw, 19.5px);
  line-height: 1.68;
  color: var(--ink-soft);
}

html[data-lang="zh"] .hero-dek {
  font-size: 16.5px;
  line-height: 1.95;
  max-width: 44em;
}

.hero-cta {
  padding-top: 2px;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 11px;
}

.cta-note {
  margin: 13px 0 0;
  font-family: var(--sans);
  font-size: 10.5px;
  letter-spacing: 0.035em;
  color: var(--faint);
}

html[data-lang="zh"] .cta-note {
  font-family: var(--sans-zh);
  font-size: 11.5px;
  letter-spacing: 0.02em;
}

/* Plates & screenshots ---------------------------------------------------- */
.hero-figure {
  margin: clamp(46px, 6vw, 72px) 0 0;
}

.plate {
  position: relative;
  display: block;
  width: 100%;
  padding: 10px;
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.7), 0 30px 60px -42px rgba(35, 37, 44, 0.6),
    0 3px 10px -6px rgba(35, 37, 44, 0.16);
}

.plate::after {
  content: "";
  position: absolute;
  inset: 4px;
  border: 1px solid var(--rule);
  pointer-events: none;
}

.plate img {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--rule);
  background: var(--paper-2);
}

.plate-button {
  padding: 10px;
  color: inherit;
  font: inherit;
  text-align: left;
  border-radius: 0;
  cursor: zoom-in;
  transition: border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.plate-button:hover {
  border-color: var(--rule-strong);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.7), 0 34px 64px -42px rgba(35, 37, 44, 0.68),
    0 3px 10px -6px rgba(35, 37, 44, 0.16);
}

.plate-expand {
  position: absolute;
  z-index: 2;
  top: 22px;
  right: 22px;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  background: rgba(var(--paper-rgb), 0.92);
  border: 1px solid var(--rule-strong);
  color: var(--ink-soft);
  opacity: 0;
  transform: translateY(-3px);
  transition: opacity 0.22s var(--ease), transform 0.22s var(--ease), color 0.22s var(--ease);
  pointer-events: none;
}

.plate-expand svg {
  width: 13px;
  height: 13px;
}

.plate-button:hover .plate-expand,
.plate-button:focus-visible .plate-expand {
  opacity: 1;
  transform: translateY(0);
  color: var(--seal);
}

figcaption {
  display: block;
  margin-top: 16px;
  max-width: 100%;
  font-size: 13px;
  font-style: italic;
  line-height: 1.6;
  color: var(--muted);
}

html[data-lang="zh"] figcaption {
  font-style: normal;
  font-size: 12.5px;
  line-height: 1.8;
}

.fig-no {
  display: inline-block;
  margin-right: 9px;
  font-family: var(--sans);
  font-size: 9.5px;
  font-style: normal;
  font-weight: 600;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--seal-ink);
  white-space: nowrap;
}

.cap-button {
  display: inline;
  margin-left: 4px;
  padding: 0;
  border: 0;
  border-bottom: 1px dotted var(--rule-strong);
  background: none;
  color: var(--accent-ink);
  font: inherit;
  font-style: normal;
  cursor: pointer;
}

.cap-button:hover {
  color: var(--seal-ink);
  border-color: var(--seal);
}

/* Premise ----------------------------------------------------------------- */
.premise {
  padding-block: clamp(52px, 6.5vw, 82px);
  background: var(--paper-2);
  border-block: 1px solid var(--rule);
}

.premise-grid {
  display: grid;
  grid-template-columns: 112px minmax(0, 1fr);
  gap: clamp(16px, 3vw, 40px);
}

.premise .kicker {
  padding-top: 10px;
  color: var(--seal-ink);
}

.premise-body {
  max-width: 900px;
}

.premise-quote {
  margin: 0;
  font-size: clamp(24px, 3.15vw, 39px);
  line-height: 1.3;
  letter-spacing: -0.018em;
  color: var(--ink);
}

.premise-quote em {
  color: var(--accent-ink);
}

html[data-lang="zh"] .premise-quote {
  font-size: clamp(21px, 2.7vw, 31px);
  line-height: 1.62;
  letter-spacing: 0.02em;
}

html[data-lang="zh"] .premise-quote em {
  font-style: normal;
  color: var(--seal-ink);
}

.premise-attrib {
  margin: 18px 0 0;
  font-size: 14.5px;
  font-style: italic;
  color: var(--muted);
}

html[data-lang="zh"] .premise-attrib {
  font-style: normal;
  font-size: 13.5px;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  margin: clamp(38px, 4.6vw, 56px) 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule-strong);
}

.steps li {
  padding: 20px 30px 0 0;
}

.steps li + li {
  padding-left: 30px;
  border-left: 1px solid var(--rule);
}

.step-no {
  display: block;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--seal-ink);
}

.steps .step-title {
  margin: 9px 0 7px;
  font-size: 20px;
  font-weight: 500;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

html[data-lang="zh"] .steps .step-title {
  font-size: 18px;
  line-height: 1.5;
  letter-spacing: 0.03em;
}

.steps p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.68;
  color: var(--muted);
}

html[data-lang="zh"] .steps p {
  font-size: 13px;
  line-height: 1.85;
}

/* Sections ---------------------------------------------------------------- */
.section {
  padding-block: var(--section-y);
}

.section-alt {
  background: linear-gradient(180deg, var(--paper-2), #f3ede1);
  border-block: 1px solid var(--rule);
}

.section-head {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: clamp(16px, 3vw, 40px);
  padding-top: 17px;
  border-top: 1px solid var(--rule-strong);
  margin-bottom: clamp(38px, 4.6vw, 58px);
}

.section-no {
  margin: 0;
  padding-top: 3px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--seal-ink);
}

.section-no::after {
  content: "";
  display: block;
  width: 28px;
  height: 1px;
  margin-top: 11px;
  background: var(--seal);
  opacity: 0.45;
}

.section-heading h2 {
  margin: 12px 0 0;
  max-width: 19ch;
  font-size: clamp(2.15rem, 4.4vw, 3.75rem);
  font-weight: 500;
  line-height: 1.03;
  letter-spacing: -0.028em;
}

html[data-lang="zh"] .section-heading h2 {
  max-width: 22em;
  font-size: clamp(1.95rem, 3.9vw, 3.2rem);
  line-height: 1.22;
  letter-spacing: 0.025em;
}

.feature-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.93fr) minmax(0, 1.07fr);
  gap: clamp(38px, 5vw, 72px);
  align-items: start;
}

.feature-grid-flip {
  grid-template-columns: minmax(0, 1.07fr) minmax(0, 0.93fr);
}

.feature-grid-flip .feature-copy {
  order: 2;
}

.feature-grid-flip .feature-visual {
  order: 1;
}

.lead {
  margin: 0 0 26px;
  font-size: clamp(16.5px, 1.35vw, 18.5px);
  line-height: 1.68;
  color: var(--ink-soft);
}

html[data-lang="zh"] .lead {
  font-size: 16px;
  line-height: 1.95;
}

.points {
  margin: 0;
  padding: 0;
  list-style: none;
}

.points li {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 12px;
  padding: 18px 0;
  border-top: 1px solid var(--rule);
}

.points li:last-child {
  padding-bottom: 0;
}

.point-mark {
  padding-top: 2px;
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: -0.02em;
  color: var(--seal);
  white-space: nowrap;
}

.points p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.68;
  color: var(--muted);
}

html[data-lang="zh"] .points p {
  font-size: 14px;
  line-height: 1.9;
}

.points strong {
  font-weight: 600;
  color: var(--ink);
}

.points code {
  font-size: 0.78em;
}

/* Spread demo ------------------------------------------------------------- */
.demo-figure {
  margin: 0;
}

.spread {
  border: 1px solid var(--rule-strong);
  background: var(--paper);
  box-shadow: 0 24px 46px -38px rgba(35, 37, 44, 0.55), 0 2px 5px -3px rgba(35, 37, 44, 0.12);
}

.spread-top {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 9px 13px;
  border-bottom: 1px solid var(--rule);
  background: var(--paper-2);
  font-family: var(--mono);
  font-size: 9.5px;
  letter-spacing: 0.045em;
  color: var(--muted);
}

.spread-file {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--ink);
  font-weight: 600;
}

.tab-dot {
  width: 5px;
  height: 5px;
  background: var(--seal);
  flex: none;
}

.spread-dir {
  padding: 2px 6px;
  border: 1px solid var(--rule-strong);
  font-size: 9px;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
  white-space: nowrap;
}

.spread-dir span {
  color: var(--seal);
  padding-inline: 2px;
}

.spread-status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: auto;
  white-space: nowrap;
}

.live-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 2px rgba(43, 74, 139, 0.12);
  flex: none;
}

.spread-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
}

.pane {
  min-width: 0;
  padding: 11px 12px 13px;
}

.pane-zh {
  position: relative;
  border-left: 1px solid var(--rule);
}

.pane-zh::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, transparent, rgba(184, 67, 47, 0.42) 12%, rgba(184, 67, 47, 0.42) 88%, transparent);
  pointer-events: none;
}

.pane-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 6px;
  padding-bottom: 6px;
  border-bottom: 1px dotted var(--rule);
  font-family: var(--mono);
  font-size: 8.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--faint);
}

.pane-file {
  font-size: 8px;
  letter-spacing: 0.04em;
  text-transform: none;
  color: var(--faint);
}

.para {
  position: relative;
  display: grid;
  grid-template-columns: 19px minmax(0, 1fr);
  gap: 5px;
  margin: 0 -5px;
  padding: 7px 5px 7px 3px;
  transition: background 0.18s var(--ease), box-shadow 0.18s var(--ease);
}

.para p {
  margin: 0;
  font-size: 12.2px;
  line-height: 1.55;
  color: var(--ink-soft);
}

.pane-zh .para p {
  font-family: var(--serif-zh);
  font-size: 11.8px;
  line-height: 1.78;
  letter-spacing: 0.01em;
}

.para code {
  font-size: 9.5px;
  padding: 0 2px;
  background: rgba(35, 37, 44, 0.045);
  overflow-wrap: anywhere;
}

.para-no {
  padding-top: 2px;
  font-family: var(--mono);
  font-size: 8px;
  line-height: 1.6;
  color: var(--faint);
  text-align: right;
}

.para.is-edited {
  background: var(--seal-wash);
  box-shadow: inset 2px 0 0 var(--seal);
}

.para.is-paired {
  background: var(--accent-wash);
  box-shadow: inset 2px 0 0 var(--accent-soft);
}

.para.is-edited .para-no {
  color: var(--seal-ink);
}

.spread-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 15px;
  padding: 8px 13px;
  border-top: 1px solid var(--rule);
  background: var(--paper-2);
  font-family: var(--mono);
  font-size: 8.8px;
  letter-spacing: 0.03em;
  color: var(--muted);
}

html[data-lang="zh"] .spread-foot {
  font-size: 9.2px;
}

.spread-foot strong {
  font-weight: 600;
  color: var(--seal-ink);
}

.spread-cost {
  margin-left: auto;
  color: var(--faint);
}

/* Placeholder card -------------------------------------------------------- */
.placeholder-card {
  margin-top: 14px;
  padding: 14px 16px 13px;
  border: 1px solid var(--rule);
  background: var(--paper-2);
}

.ph-kicker {
  margin: 0 0 8px;
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--seal-ink);
}

.ph-row {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  padding: 7px 0;
  border-top: 1px dotted var(--rule-strong);
}

.ph-label {
  padding-top: 2px;
  font-family: var(--mono);
  font-size: 8.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--faint);
}

.ph-row p {
  margin: 0;
  font-family: var(--mono);
  font-size: 10.3px;
  line-height: 1.7;
  color: var(--ink-soft);
  overflow-wrap: anywhere;
}

.ph-row mark {
  padding: 0 2px;
  background: rgba(184, 67, 47, 0.12);
  color: var(--seal-ink);
  font-weight: 600;
}

.ph-row code {
  padding: 0;
  background: none;
  font-size: 0.98em;
  color: var(--accent-ink);
}

.ph-note {
  margin: 8px 0 0;
  font-family: var(--sans);
  font-size: 10.5px;
  line-height: 1.55;
  color: var(--muted);
}

html[data-lang="zh"] .ph-note {
  font-family: var(--sans-zh);
  font-size: 11px;
  line-height: 1.7;
}

/* Screenshot figures ------------------------------------------------------- */
.shot {
  margin: 0;
}

.shot .plate {
  padding: 7px;
}

.shot figcaption {
  margin-top: 14px;
}

/* Assistant --------------------------------------------------------------- */
.assistant-note {
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr);
  gap: 12px;
  margin: 28px 0 20px;
  padding: 16px 18px;
  border: 1px solid var(--rule-strong);
  background: rgba(255, 255, 255, 0.26);
}

.note-mark {
  color: var(--seal);
}

.note-mark svg {
  width: 13px;
  height: 13px;
  margin-top: 4px;
}

.assistant-note p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.67;
  color: var(--ink-soft);
}

html[data-lang="zh"] .assistant-note p {
  font-size: 13px;
  line-height: 1.9;
}

.assistant-note strong {
  font-weight: 600;
  color: var(--ink);
}

.assistant-aside {
  margin: 0;
  padding-left: 14px;
  border-left: 2px solid var(--rule);
  font-size: 13px;
  font-style: italic;
  line-height: 1.65;
  color: var(--muted);
}

html[data-lang="zh"] .assistant-aside {
  font-style: normal;
  font-size: 12.5px;
  line-height: 1.85;
}

.action-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: clamp(42px, 5vw, 64px);
  border-top: 1px solid var(--rule-strong);
  border-left: 1px solid var(--rule);
}

.action-card {
  padding: 24px 24px 26px;
  border-right: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  transition: background 0.22s var(--ease);
}

.action-card:hover {
  background: rgba(255, 255, 255, 0.3);
}

.action-icon {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  margin-bottom: 17px;
  border: 1px solid var(--rule-strong);
  color: var(--seal);
  transition: background 0.22s var(--ease), color 0.22s var(--ease), border-color 0.22s var(--ease);
}

.action-card:hover .action-icon {
  background: var(--seal);
  border-color: var(--seal);
  color: var(--cream);
}

.action-icon svg {
  width: 17px;
  height: 17px;
}

.action-card h3 {
  margin: 0 0 7px;
  font-size: 20px;
  font-weight: 500;
  letter-spacing: -0.01em;
}

html[data-lang="zh"] .action-card h3 {
  font-size: 18px;
  letter-spacing: 0.03em;
}

.action-card p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.62;
  color: var(--muted);
}

html[data-lang="zh"] .action-card p {
  font-size: 13px;
  line-height: 1.85;
}

/* Method band ------------------------------------------------------------- */
.method {
  position: relative;
  overflow: hidden;
  padding-block: clamp(64px, 8vw, 108px);
  background:
    radial-gradient(ellipse 70% 90% at 88% 0%, rgba(147, 172, 234, 0.13), transparent 58%),
    radial-gradient(ellipse 50% 70% at 0% 100%, rgba(184, 67, 47, 0.1), transparent 60%),
    var(--navy);
  color: var(--cream);
}

.method::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(rgba(243, 236, 222, 0.045) 1px, transparent 1px);
  background-size: 100% 52px;
  mask-image: linear-gradient(to right, transparent, black 20%, black 80%, transparent);
  -webkit-mask-image: linear-gradient(to right, transparent, black 20%, black 80%, transparent);
}

.method-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
  gap: clamp(42px, 6vw, 92px);
  align-items: start;
}

.kicker-light {
  color: rgba(243, 236, 222, 0.56);
}

.method h2 {
  margin: 15px 0 20px;
  max-width: 15ch;
  font-size: clamp(2.3rem, 4.5vw, 3.9rem);
  font-weight: 500;
  line-height: 1.04;
  letter-spacing: -0.025em;
  color: var(--cream);
}

html[data-lang="zh"] .method h2 {
  max-width: 16em;
  font-size: clamp(2rem, 3.9vw, 3.1rem);
  line-height: 1.25;
  letter-spacing: 0.03em;
}

.method-lead {
  margin: 0 0 24px;
  max-width: 52ch;
  font-size: 15.5px;
  line-height: 1.72;
  color: rgba(243, 236, 222, 0.72);
}

html[data-lang="zh"] .method-lead {
  font-size: 14.5px;
  line-height: 1.95;
}

.method-lead a {
  color: var(--cream);
  text-decoration: underline;
  text-decoration-color: rgba(224, 122, 98, 0.6);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.method-lead a:hover {
  text-decoration-color: var(--cream);
}

.method-lead code {
  color: var(--cream);
  background: rgba(243, 236, 222, 0.1);
}

.method-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 4px;
  border-bottom: 1px solid rgba(243, 236, 222, 0.35);
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--cream);
  text-decoration: none;
  transition: border-color 0.2s var(--ease), gap 0.2s var(--ease);
}

html[data-lang="zh"] .method-link {
  font-family: var(--sans-zh);
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: none;
}

.method-link:hover {
  border-color: var(--cream);
  gap: 12px;
}

.method-link svg {
  width: 13px;
  height: 13px;
}

.method-list {
  border-top: 1px solid rgba(243, 236, 222, 0.24);
}

.method-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 14px;
  padding: 14px 0 15px;
  border-bottom: 1px solid rgba(243, 236, 222, 0.16);
}

.method-no {
  padding-top: 3px;
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.1em;
  color: #e58a74;
}

.method-item h3 {
  margin: 0;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0;
  color: var(--cream);
}

html[data-lang="zh"] .method-item h3 {
  font-size: 15.5px;
}

.method-item p {
  margin: 2px 0 0;
  font-size: 12.5px;
  line-height: 1.55;
  color: rgba(243, 236, 222, 0.58);
}

html[data-lang="zh"] .method-item p {
  font-size: 12.5px;
  line-height: 1.75;
}

.seal-stamp {
  position: absolute;
  right: clamp(20px, 5vw, 64px);
  bottom: clamp(16px, 3vw, 40px);
  z-index: 0;
  display: grid;
  place-items: center;
  width: clamp(94px, 12vw, 142px);
  height: clamp(94px, 12vw, 142px);
  border: 2px solid rgba(224, 122, 98, 0.22);
  color: rgba(224, 122, 98, 0.2);
  font-family: var(--serif-zh);
  font-size: clamp(40px, 5.4vw, 64px);
  line-height: 1;
  transform: rotate(-8deg);
  pointer-events: none;
}

.seal-stamp::before {
  content: "";
  position: absolute;
  inset: 6px;
  border: 1px solid rgba(224, 122, 98, 0.16);
}

/* More grid --------------------------------------------------------------- */
.more-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--rule-strong);
  border-left: 1px solid var(--rule);
}

.more-card {
  display: flex;
  flex-direction: column;
  min-height: 264px;
  padding: 25px 23px 22px;
  border-right: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  transition: background 0.22s var(--ease);
}

.more-card:hover {
  background: rgba(255, 255, 255, 0.32);
}

.more-icon {
  width: 20px;
  height: 20px;
  margin-bottom: 19px;
  color: var(--seal);
}

.more-icon svg {
  width: 20px;
  height: 20px;
}

.more-card h3 {
  margin: 0 0 8px;
  font-size: 19px;
  font-weight: 500;
  letter-spacing: -0.008em;
}

html[data-lang="zh"] .more-card h3 {
  font-size: 17.5px;
  letter-spacing: 0.03em;
}

.more-card p {
  margin: 0 0 14px;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--muted);
}

html[data-lang="zh"] .more-card p {
  font-size: 13px;
  line-height: 1.85;
}

.more-card code {
  font-size: 0.84em;
}

.more-tag {
  margin-top: auto;
  padding-top: 10px;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 8.5px;
  letter-spacing: 0.06em;
  color: var(--faint);
}

html[data-lang="zh"] .more-tag {
  font-size: 9px;
}

.footnote {
  display: grid;
  grid-template-columns: 20px minmax(0, 1fr);
  gap: 8px;
  margin: 22px 0 0;
  font-size: 12px;
  line-height: 1.65;
  color: var(--muted);
}

html[data-lang="zh"] .footnote {
  font-size: 12px;
  line-height: 1.85;
}

.fn-mark {
  color: var(--seal);
}

/* Download ---------------------------------------------------------------- */
.download {
  padding-block: clamp(60px, 8vw, 104px);
  background: var(--paper-2);
  border-top: 1px solid var(--rule-strong);
}

.download-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: clamp(40px, 6vw, 90px);
  align-items: start;
}

.download h2 {
  margin: 14px 0 18px;
  font-size: clamp(2.6rem, 5vw, 4.35rem);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.032em;
}

html[data-lang="zh"] .download h2 {
  font-size: clamp(2.2rem, 4.2vw, 3.5rem);
  line-height: 1.2;
  letter-spacing: 0.03em;
}

.download-lead {
  margin: 0;
  max-width: 45ch;
  font-size: 16.5px;
  line-height: 1.7;
  color: var(--ink-soft);
}

html[data-lang="zh"] .download-lead {
  font-size: 15.5px;
  line-height: 1.9;
}

.version-line {
  margin: 28px 0 0;
  font-family: var(--mono);
  font-size: 9.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--faint);
}

html[data-lang="zh"] .version-line {
  font-size: 10px;
  letter-spacing: 0.05em;
}

.version-line::before {
  content: "";
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-right: 8px;
  background: var(--seal);
  vertical-align: 1px;
}

.download-actions {
  display: flex;
  flex-direction: column;
  gap: 11px;
}

.dl-btn {
  position: relative;
  display: grid;
  grid-template-columns: 24px minmax(0, 1fr) 18px;
  align-items: center;
  gap: 16px;
  padding: 18px 20px;
  border: 1px solid var(--rule-strong);
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  transition: border-color 0.22s var(--ease), background 0.22s var(--ease), transform 0.22s var(--ease),
    box-shadow 0.22s var(--ease);
}

.dl-btn:hover {
  border-color: var(--seal);
  background: #faf6ee;
  transform: translateY(-1px);
  box-shadow: 0 16px 30px -26px rgba(35, 37, 44, 0.6);
}

.platform {
  width: 21px;
  height: 23px;
  color: var(--navy);
  justify-self: center;
}

.dl-text {
  display: block;
  min-width: 0;
}

.dl-text strong {
  display: block;
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 500;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

html[data-lang="zh"] .dl-text strong {
  font-size: 17px;
  letter-spacing: 0.02em;
}

.dl-text small {
  display: block;
  margin-top: 3px;
  font-family: var(--mono);
  font-size: 9px;
  line-height: 1.4;
  letter-spacing: 0.03em;
  color: var(--muted);
}

html[data-lang="zh"] .dl-text small {
  font-size: 9.5px;
}

.dl-arrow {
  width: 17px;
  height: 17px;
  color: var(--seal);
  transition: transform 0.22s var(--ease);
}

.dl-btn:hover .dl-arrow {
  transform: translateX(3px);
}

.all-releases {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  align-self: flex-start;
  margin-top: 5px;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--rule-strong);
  font-family: var(--sans);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

html[data-lang="zh"] .all-releases {
  font-family: var(--sans-zh);
  font-size: 11.5px;
  font-weight: 400;
}

.all-releases:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.all-releases svg {
  width: 11px;
  height: 11px;
}

.notes-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(28px, 4vw, 48px);
  margin-top: clamp(48px, 6vw, 68px);
  padding-top: 26px;
  border-top: 1px solid var(--rule-strong);
}

.note-col h3 {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 9.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--seal-ink);
}

html[data-lang="zh"] .note-col h3 {
  font-size: 10px;
  letter-spacing: 0.08em;
}

.note-col ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.note-col li {
  position: relative;
  margin-bottom: 7px;
  padding-left: 14px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

html[data-lang="zh"] .note-col li {
  font-size: 12.5px;
  line-height: 1.8;
}

.note-col li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 4px;
  height: 4px;
  background: var(--seal);
  opacity: 0.65;
}

.note-col p {
  margin: 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

html[data-lang="zh"] .note-col p {
  font-size: 12.5px;
  line-height: 1.85;
}

.note-col em {
  font-style: italic;
  color: var(--ink-soft);
}

html[data-lang="zh"] .note-col em {
  font-style: normal;
  border-bottom: 1px dotted var(--rule-strong);
}

.faq {
  display: grid;
  border-bottom: 1px solid var(--rule);
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(32px, 5vw, 64px);
  margin-top: clamp(38px, 5vw, 54px);
}

.faq details {
  border-top: 1px solid var(--rule);
}

.faq summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  padding: 15px 0;
  font-family: var(--serif);
  font-size: 16px;
  font-weight: 500;
  line-height: 1.35;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
}

html[data-lang="zh"] .faq summary {
  font-family: var(--serif-zh);
  font-size: 15px;
  line-height: 1.6;
}

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

.faq summary svg {
  width: 13px;
  height: 13px;
  flex: none;
  color: var(--seal);
  transition: transform 0.24s var(--ease);
}

.faq details[open] summary svg {
  transform: rotate(45deg);
}

.faq details p {
  margin: 0;
  padding: 0 0 16px;
  max-width: 56ch;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--muted);
}

html[data-lang="zh"] .faq details p {
  font-size: 13px;
  line-height: 1.85;
}

/* Footer ------------------------------------------------------------------ */
.site-footer {
  padding: clamp(48px, 6vw, 76px) 0 30px;
  background: var(--navy-deep);
  color: var(--cream);
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1.35fr);
  gap: clamp(36px, 6vw, 80px);
  padding-bottom: 38px;
  border-bottom: 1px solid rgba(243, 236, 222, 0.16);
}

.footer-brand .brand {
  color: var(--cream);
}

.footer-brand .brand-mark {
  width: 30px;
  height: 30px;
}

.footer-brand p {
  margin: 16px 0 0;
  max-width: 30ch;
  font-size: 13.5px;
  line-height: 1.65;
  color: rgba(243, 236, 222, 0.6);
}

html[data-lang="zh"] .footer-brand p {
  font-size: 13px;
  line-height: 1.85;
}

.footer-brand .footer-version {
  margin-top: 12px;
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.1em;
  color: rgba(243, 236, 222, 0.55);
}

.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 28px;
}

.footer-col h3 {
  margin: 0 0 14px;
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 500;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: rgba(243, 236, 222, 0.55);
}

html[data-lang="zh"] .footer-col h3 {
  font-size: 9.5px;
  letter-spacing: 0.08em;
}

.footer-col a {
  display: block;
  width: fit-content;
  margin-bottom: 4px;
  padding-block: 3px;
  font-size: 13px;
  line-height: 1.5;
  color: rgba(243, 236, 222, 0.78);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

html[data-lang="zh"] .footer-col a {
  font-size: 12.5px;
}

.footer-col a:hover {
  color: var(--cream);
  border-color: rgba(243, 236, 222, 0.35);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding-top: 22px;
  font-family: var(--sans);
  font-size: 10.5px;
  line-height: 1.65;
  color: rgba(243, 236, 222, 0.55);
}

.footer-bottom p {
  margin: 0;
  max-width: 65ch;
}

html[data-lang="zh"] .footer-bottom {
  font-family: var(--sans-zh);
  font-size: 11px;
}

.footer-mark {
  font-family: var(--serif);
  font-style: italic;
  color: rgba(243, 236, 222, 0.65) !important;
  white-space: nowrap;
}

html[data-lang="zh"] .footer-mark {
  font-family: var(--serif-zh);
  font-style: normal;
}

/* Lightbox ---------------------------------------------------------------- */
.lightbox {
  width: min(1500px, 94vw);
  max-width: none;
  max-height: 94vh;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--cream);
  overflow: visible;
}

.lightbox::backdrop {
  background: rgba(18, 21, 29, 0.88);
  -webkit-backdrop-filter: blur(7px);
  backdrop-filter: blur(7px);
}

.lightbox[open] {
  animation: lightbox-in 0.26s var(--ease);
}

.lightbox[open]::backdrop {
  animation: backdrop-in 0.26s var(--ease);
}

@keyframes lightbox-in {
  from {
    opacity: 0;
    transform: translateY(8px) scale(0.995);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes backdrop-in {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.lightbox-body {
  padding: 10px;
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  box-shadow: 0 40px 100px -40px rgba(0, 0, 0, 0.75);
}

.lightbox img {
  display: block;
  width: auto;
  max-width: 100%;
  max-height: calc(94vh - 86px);
  margin-inline: auto;
  border: 1px solid var(--rule);
  background: var(--paper-2);
}

.lightbox p {
  margin: 11px 8px 4px;
  font-family: var(--serif);
  font-size: 12.5px;
  font-style: italic;
  line-height: 1.55;
  color: var(--muted);
}

html[data-lang="zh"] .lightbox p {
  font-family: var(--serif-zh);
  font-style: normal;
  font-size: 12px;
  line-height: 1.75;
}

.lightbox-close {
  position: absolute;
  z-index: 3;
  top: 20px;
  right: 20px;
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  padding: 0;
  border: 1px solid var(--rule-strong);
  background: rgba(247, 242, 232, 0.94);
  color: var(--ink);
  cursor: pointer;
  transition: background 0.2s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.lightbox-close:hover {
  background: var(--seal);
  border-color: var(--seal);
  color: var(--cream);
}

.lightbox-close svg {
  width: 14px;
  height: 14px;
}

body.dialog-open {
  overflow: hidden;
}

/* Reveal ------------------------------------------------------------------ */
.js .reveal {
  opacity: 0;
  transform: translateY(13px);
  transition: opacity 0.72s var(--ease), transform 0.72s var(--ease);
}

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

/* Responsive -------------------------------------------------------------- */
@media (max-width: 1080px) {
  .nav-links {
    gap: 20px;
  }

  .hero-title {
    font-size: clamp(3.2rem, 8.8vw, 6.6rem);
  }
}

@media (max-width: 1000px) {
  .feature-grid,
  .feature-grid-flip {
    grid-template-columns: minmax(0, 1fr);
    gap: clamp(34px, 5vw, 48px);
  }

  .feature-grid-flip .feature-copy {
    order: 1;
  }

  .feature-grid-flip .feature-visual {
    order: 2;
  }

  .shot .plate {
    max-width: 100%;
  }

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

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

  .method-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 42px;
  }

  .method h2 {
    max-width: 18ch;
  }

  .seal-stamp {
    opacity: 0.65;
  }
}

@media (max-width: 900px) {
  .nav-links {
    display: none;
  }

  .nav {
    gap: 18px;
  }

  .hero-bottom {
    grid-template-columns: minmax(0, 1fr);
    gap: 30px;
  }

  .hero-cta {
    padding-top: 0;
  }

  .premise-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 18px;
  }

  .premise .kicker {
    padding-top: 0;
  }

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

  .steps li {
    padding: 18px 0 18px 0;
  }

  .steps li + li {
    padding-left: 0;
    border-left: 0;
    border-top: 1px solid var(--rule);
  }

  .download-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 36px;
  }

  .notes-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
  }

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

  .footer-main {
    grid-template-columns: minmax(0, 1fr);
    gap: 36px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 8px;
  }
}

@media (max-width: 760px) {
  :root {
    --section-y: clamp(52px, 9vw, 76px);
  }

  html {
    scroll-padding-top: 80px;
  }

  .nav {
    height: 62px;
  }

  .brand-mark {
    width: 24px;
    height: 24px;
  }

  .brand-name {
    font-size: 19px;
  }

  .hero-meta {
    flex-direction: column;
    gap: 6px;
    align-items: flex-start;
  }

  .hero-meta-right {
    text-align: left;
    white-space: normal;
  }

  .hero-title {
    font-size: clamp(3rem, 14vw, 5.4rem);
    line-height: 0.98;
  }

  .hero-title-zh {
    font-size: clamp(2.7rem, 11.5vw, 4.3rem);
  }

  .section-head {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
  }

  .section-no {
    display: flex;
    align-items: center;
    gap: 12px;
    padding-top: 0;
  }

  .section-no::after {
    margin-top: 0;
  }

  .section-heading h2 {
    margin-top: 9px;
    max-width: none;
  }

  .plate {
    padding: 6px;
  }

  .plate::after {
    inset: 2px;
  }

  .plate-button {
    padding: 6px;
  }

  .plate-expand {
    display: none;
  }

  .shot .plate {
    padding: 5px;
  }

  .spread-body {
    grid-template-columns: minmax(0, 1fr);
  }

  .pane-zh {
    border-left: 0;
    border-top: 1px solid var(--rule);
  }

  .pane-zh::before {
    left: 0;
    right: 0;
    top: -1px;
    bottom: auto;
    width: auto;
    height: 2px;
    background: linear-gradient(to right, transparent, rgba(184, 67, 47, 0.4) 12%, rgba(184, 67, 47, 0.4) 88%, transparent);
  }

  .pane-zh .pane-head {
    margin-top: 5px;
  }

  .action-grid {
    border-left: 0;
  }

  .action-card {
    border-left: 1px solid var(--rule);
  }

  .more-grid {
    grid-template-columns: minmax(0, 1fr);
    border-left: 0;
  }

  .more-card {
    border-left: 1px solid var(--rule);
    min-height: 0;
  }

  .footer-cols {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .seal-stamp {
    display: none;
  }
}

@media (max-width: 620px) {
  .nav-actions {
    gap: 8px;
  }

  .nav-github {
    display: none;
  }

  .lang-switch button {
    padding: 6px;
  }

  .cta-row {
    flex-direction: column;
    align-items: stretch;
  }

  .cta-row .btn {
    width: 100%;
  }

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

  .cta-note {
    max-width: 34ch;
  }

  .dl-btn {
    grid-template-columns: 22px minmax(0, 1fr) 16px;
    gap: 13px;
    padding: 16px;
  }

  .faq {
    margin-top: 30px;
  }
}

@media (max-width: 460px) {
  .nav {
    gap: 12px;
  }

  .brand {
    gap: 8px;
  }

  .btn-small {
    padding: 8px 10px;
    font-size: 9.5px;
  }

  .hero-title {
    font-size: clamp(2.8rem, 15.5vw, 4.5rem);
  }

  .hero-title-zh {
    font-size: clamp(2.4rem, 12.5vw, 3.6rem);
  }

  .hero-gloss {
    font-size: 14.5px;
  }

  .hero-gloss[lang="en"] {
    font-size: 14px;
  }

  .hero-dek {
    font-size: 16px;
  }

  .premise-quote {
    font-size: 24px;
  }

  .download-lead {
    font-size: 15px;
  }

  .footer-cols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px 18px;
  }

  .footer-brand p {
    max-width: 26ch;
  }

  .lightbox {
    width: 96vw;
  }

  .lightbox-close {
    top: 14px;
    right: 14px;
  }
}

@media (hover: none) {
  .plate-expand {
    display: none;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .js .reveal {
    opacity: 1;
    transform: none;
  }
}

/* Utilities --------------------------------------------------------------- */
.sr-only {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 380px) {
  .spread-top {
    flex-wrap: wrap;
    row-gap: 5px;
  }

  .spread-dir {
    margin-left: auto;
  }

  .spread-status {
    width: 100%;
    margin-left: 0;
  }
}

/* Lightbox caption row (appended) */
.lightbox-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 5px 18px;
  margin: 11px 8px 4px;
}

.lightbox p {
  margin: 0;
}

.lightbox-original {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 2px 3px;
  border-bottom: 1px solid var(--rule-strong);
  font-family: var(--sans);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-ink);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

html[data-lang="zh"] .lightbox-original {
  font-family: var(--sans-zh);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.02em;
  text-transform: none;
}

.lightbox-original:hover {
  color: var(--seal-ink);
  border-color: var(--seal);
}

.lightbox-original svg {
  width: 11px;
  height: 11px;
}

.lightbox-close:focus-visible {
  outline-color: var(--seal);
}

main:focus {
  outline: none;
}

/* Keep the emphasised closing line of the Chinese premise intact. */
html[data-lang="zh"] .premise-quote em {
  white-space: nowrap;
}

html[data-lang="zh"] .footer-brand p {
  max-width: 26em;
}

.nowrap {
  white-space: nowrap;
}