/*
 * BELL PR landing site. Light theme only, no build step and nothing loaded
 * from another origin. A quiet, spacious presentation of the local workbench;
 * brand colors are shared with the app and fonts are self-hosted.
 */

/* DM Sans (variable weight) and IBM Plex Mono, SIL Open Font License 1.1;
   the licenses are next to the files. unicode-range matches fontsource. */
@font-face {
  font-family: "DM Sans";
  font-style: normal;
  font-display: swap;
  font-weight: 100 1000;
  src: url("assets/fonts/dm-sans-latin-ext-wght-normal.woff2") format("woff2");
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7,
    U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F,
    U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F,
    U+A720-A7FF;
}
@font-face {
  font-family: "DM Sans";
  font-style: normal;
  font-display: swap;
  font-weight: 100 1000;
  src: url("assets/fonts/dm-sans-latin-wght-normal.woff2") format("woff2");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6,
    U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122,
    U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-display: swap;
  font-weight: 400;
  src: url("assets/fonts/ibm-plex-mono-latin-400-normal.woff2") format("woff2");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6,
    U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122,
    U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-display: swap;
  font-weight: 500;
  src: url("assets/fonts/ibm-plex-mono-latin-500-normal.woff2") format("woff2");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6,
    U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122,
    U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

:root {
  --bg: #ffffff;
  --surface: #ffffff;
  --sunken: #f5f5f7;
  --muted: #ededf0;
  --border: #e5e5e8;
  --border-strong: #d2d2d7;
  --text: #1d1d1f;
  --text-secondary: #515155;
  --text-muted: #68686d;
  --text-inverse: #ffffff;
  --text-inverse-muted: #d3e0d6;
  --brand-700: #175a40;
  --brand-600: #1f6d50;
  --brand-300: #8dbb9f;
  --brand-100: #e0eee4;
  --brand-50: #eef6f0;
  --warning: #765a17;
  --warning-border: #e6d7ae;
  --warning-bg: #fbf6e7;

  --font-sans: "DM Sans", system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas,
    "Liberation Mono", monospace;

  --radius-sm: 6px;
  --radius-md: 16px;
  --radius-lg: 28px;
  --shadow: 0 16px 48px -16px rgb(0 0 0 / 12%), 0 1px 4px rgb(0 0 0 / 3%);
  --focus-ring: 0 0 0 2px var(--bg), 0 0 0 4px var(--brand-600);
  --gutter: clamp(20px, 5vw, 40px);
  color-scheme: light;
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

[id] {
  scroll-margin-top: 92px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.6;
  overflow-wrap: break-word;
}

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

a {
  color: var(--brand-700);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover {
  color: var(--brand-600);
}
a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
  border-radius: var(--radius-sm);
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.15;
  letter-spacing: -0.02em;
  text-wrap: balance;
}
h1 {
  font-size: clamp(42px, 6vw, 80px);
  font-weight: 650;
  letter-spacing: -0.055em;
}
h2 {
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 650;
  letter-spacing: -0.04em;
}
h3 {
  font-size: 19px;
  font-weight: 650;
  letter-spacing: -0.01em;
}
p {
  margin: 0;
}

code,
pre {
  font-family: var(--font-mono);
  font-size: 0.9em;
}
:not(pre) > code {
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  background: var(--muted);
  color: var(--text);
}

.skip-link {
  position: absolute;
  left: 12px;
  top: -100px;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  background: var(--text);
  color: var(--text-inverse);
  z-index: 10;
}
.skip-link:focus {
  top: 12px;
  color: var(--text-inverse);
}

.wrap {
  width: 100%;
  max-width: calc(1160px + 2 * var(--gutter));
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* A persistent, quiet way back to installation. */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgb(0 0 0 / 6%);
  background: rgb(255 255 255 / 92%);
  -webkit-backdrop-filter: blur(18px);
  backdrop-filter: blur(18px);
}
.site-header .wrap {
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 72px;
  padding-top: 8px;
  padding-bottom: 8px;
}
.brand {
  display: inline-flex;
  flex-shrink: 0;
  align-items: center;
  min-height: 44px;
  border-radius: var(--radius-sm);
}
.brand img {
  width: 104px;
  height: auto;
}
.site-nav {
  margin-left: auto;
}
.site-nav ul {
  display: flex;
  align-items: center;
  gap: 24px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.site-nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 500;
  text-decoration: none;
}
.site-nav a:hover {
  color: var(--brand-700);
}
.nav-cta {
  display: inline-flex;
  flex-shrink: 0;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 9px 18px;
  border-radius: 999px;
  background: var(--brand-600);
  color: var(--text-inverse);
  font-size: 13px;
  font-weight: 550;
  text-decoration: none;
}
.nav-cta:hover {
  background: var(--brand-700);
  color: var(--text-inverse);
}

/* Sections */
main {
  display: block;
}
.section {
  padding: clamp(72px, 9vw, 120px) 0;
}
.section-tinted {
  background: var(--sunken);
}
.section-head {
  max-width: 760px;
  margin-bottom: clamp(36px, 5vw, 64px);
}
.section-head p {
  max-width: 38em;
  margin-top: 18px;
  color: var(--text-secondary);
  font-size: 19px;
  line-height: 1.6;
}
.section-head .eyebrow {
  margin-top: 0;
  font-size: 13px;
}
.centered,
.demo-section .section-head {
  margin-right: auto;
  margin-left: auto;
  text-align: center;
}
.centered p,
.demo-section .section-head p {
  margin-right: auto;
  margin-left: auto;
}
.eyebrow {
  margin-bottom: 16px;
  color: var(--brand-700);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
}

/* Product first: a short introduction and the actual workbench. */
.hero {
  padding: clamp(64px, 7vw, 100px) 0 64px;
  background: var(--bg);
}
.hero-copy {
  max-width: 960px;
  margin: 0 auto;
  text-align: center;
}
.hero h1 {
  line-height: 1.06;
}
.hero-line {
  display: block;
}
.hero h1:lang(zh-Hant-TW),
.page-head h1:lang(zh-Hant-TW) {
  line-height: 1.2;
  letter-spacing: 0;
}
.hero-accent,
.page-head h1 span {
  color: var(--brand-600);
}
.hero .lead {
  max-width: 620px;
  margin: 24px auto 0;
  color: var(--text-secondary);
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.55;
  text-wrap: balance;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 12px 28px;
  margin-top: 30px;
}
.hero-note {
  margin-top: 20px;
  color: var(--text-muted);
  font-size: 13px;
}
.text-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 48px;
  font-size: 16px;
  text-decoration: none;
}
.text-link:hover {
  text-decoration: underline;
}
.hero-product {
  max-width: 1100px;
  margin: clamp(44px, 5vw, 72px) auto 0;
}
.product-window {
  overflow: hidden;
  border: 1px solid #e1e3e1;
  border-radius: 20px;
  background: var(--surface);
  box-shadow: 0 30px 70px -24px rgb(32 48 40 / 22%), 0 2px 8px rgb(0 0 0 / 4%);
}
.window-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 38px;
  padding: 0 18px;
  background: #f6f7f6;
  color: var(--text-muted);
  font-size: 10px;
}
.window-dots {
  display: flex;
  flex: 1;
  gap: 6px;
}
.window-dots i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #d5d9d6;
}
.window-state {
  flex: 1;
  text-align: right;
}
.product-window a {
  display: block;
}
.product-window img {
  width: 100%;
  height: auto;
}
.hero-product figcaption {
  margin-top: 24px;
  color: var(--text-muted);
  font-size: 13px;
  text-align: center;
}
.install-section {
  padding-block: clamp(64px, 7vw, 96px);
  background: var(--sunken);
}
.install-section .section-head {
  margin-bottom: clamp(28px, 4vw, 44px);
}
.install-section .install-widget {
  margin-right: auto;
  margin-left: auto;
}
.install-footnote {
  max-width: 720px;
  margin: 24px auto 0;
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.7;
  text-align: center;
}
.closing-section {
  background: var(--sunken);
  text-align: center;
}
.closing-section h2 {
  font-size: clamp(36px, 5vw, 64px);
}
.closing-section .button {
  margin-top: 32px;
}

/* Promo video */
.promo-video {
  margin: 0 auto;
  max-width: 1040px;
}
.promo-video video {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  background: #0b1a14;
  box-shadow: var(--shadow);
}

/* Installation methods remain readable as sections until site.js enables tabs. */
.install-widget {
  width: 100%;
  max-width: 880px;
  min-width: 0;
}
.install-widget [hidden] {
  display: none !important;
}
.install-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0 24px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border-strong);
}
.install-tabs {
  display: flex;
  gap: 10px;
  margin-bottom: -1px;
}
.install-tab {
  min-width: 44px;
  min-height: 44px;
  padding: 10px 4px;
  border: 0;
  border-bottom: 2px solid transparent;
  background: transparent;
  color: var(--text-muted);
  font: 500 14px var(--font-mono);
  cursor: pointer;
  transition: color 150ms, border-color 150ms;
}
.install-tab:hover {
  color: var(--brand-700);
}
.install-tab[aria-selected="true"] {
  border-bottom-color: var(--brand-600);
  color: var(--brand-700);
}
.install-meta {
  display: flex;
  align-items: center;
  gap: 18px;
  margin-left: auto;
  white-space: nowrap;
}
.install-platform {
  color: var(--text-muted);
  font-size: 12px;
}
[data-install-platform] {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}
.install-guide {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 44px;
  font-size: 13px;
  font-weight: 500;
  text-decoration: none;
}
.install-guide:hover {
  text-decoration: underline;
}
.install-panel {
  padding: 20px 0;
}
.install-panel + .install-panel {
  border-top: 1px solid var(--border);
}
.install-method-title {
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 19px;
}
.install-panel > .install-platform {
  margin: 0 0 10px;
}
.install-enhanced .install-panel {
  padding: 0;
  border-top: 0;
}
.install-enhanced .install-method-title,
.install-enhanced .install-panel > .install-platform {
  display: none;
}
/* Code keeps its source whitespace. Only the code scrolls on narrow screens. */
.install-command {
  --command-bg: #172e25;
  --command-border: #355145;
  display: flex;
  align-items: center;
  gap: 18px;
  width: 100%;
  min-height: 62px;
  padding: 8px 8px 8px 20px;
  border: 1px solid var(--command-border);
  border-radius: 12px;
  background: var(--command-bg);
  color: #f2f7f4;
  box-shadow: 0 4px 12px rgb(23 46 37 / 8%);
}
.install-command code {
  flex: 1;
  min-width: 0;
  overflow-x: auto;
  padding: 10px 0;
  background: none;
  color: inherit;
  font-size: 14px;
  font-weight: 400;
  line-height: 1.65;
  white-space: pre;
  overflow-wrap: normal;
  scrollbar-width: thin;
  scrollbar-color: var(--brand-300) transparent;
}
.install-command code:focus-visible {
  outline: 2px solid var(--brand-300);
  outline-offset: -2px;
}
.install-command .copy-button {
  display: inline-flex;
  flex-shrink: 0;
  align-self: flex-start;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-width: 86px;
  min-height: 44px;
  padding: 8px 12px;
  border: 1px solid var(--command-border);
  border-radius: 6px;
  background: transparent;
  color: #d7e9dd;
  font: 500 12px var(--font-sans);
  cursor: pointer;
}
.install-command .copy-button::before {
  content: "";
  width: 10px;
  height: 12px;
  border: 1px solid currentColor;
  border-radius: 2px;
  box-shadow: -3px -3px 0 -1px var(--command-bg), -3px -3px 0 0 currentColor;
}
.install-command .copy-button:hover {
  background: #284537;
}
.install-command .copy-button:focus-visible {
  outline-color: var(--brand-300);
}
.install-command .copy-button[data-copy-state="copied"]::before {
  width: 6px;
  height: 10px;
  border-width: 0 2px 2px 0;
  border-radius: 0;
  box-shadow: none;
  transform: translateY(-1px) rotate(45deg);
}
.install-note,
.install-next {
  margin: 12px 0 0;
  color: var(--text-secondary);
  font-size: 13px;
  line-height: 1.6;
}
.install-next {
  margin-top: 4px;
  color: var(--text-muted);
}
@media (max-width: 760px) {
  .install-toolbar {
    gap: 6px;
    border-bottom: 0;
    margin-bottom: 8px;
  }
  .install-tabs {
    width: 100%;
    justify-content: space-between;
    gap: 4px;
    border-bottom: 1px solid var(--border-strong);
  }
  .install-tab {
    padding: 10px 2px;
    font-size: 13px;
  }
  .install-guide {
    font-size: 12px;
  }
  .install-command {
    gap: 8px;
    padding-left: 14px;
  }
  .install-command code {
    font-size: 13px;
  }
}
@media (max-width: 380px) {
  .install-tabs {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
  }
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 12px 24px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text);
  font-size: 16px;
  font-weight: 500;
  text-decoration: none;
  transition: background-color 160ms, box-shadow 160ms;
}
.button:hover {
  border-color: var(--brand-600);
  color: var(--brand-700);
}
.button-primary {
  border-color: transparent;
  background: var(--brand-600);
  color: var(--text-inverse);
}
.button-primary:hover {
  background: var(--brand-700);
  color: var(--text-inverse);
  box-shadow: 0 4px 14px rgb(31 109 80 / 16%);
}

/* Secondary detail is available without competing with the product story. */
.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.card {
  min-width: 0;
  padding: 32px;
  border-radius: var(--radius-lg);
  background: var(--sunken);
}
.card p {
  max-width: 36em;
  margin-top: 14px;
  color: var(--text-secondary);
  font-size: 16px;
}
.card h3 {
  font-size: 22px;
  line-height: 1.3;
}
.feature-groups {
  display: grid;
  gap: 16px;
}
.feature-group {
  border-radius: var(--radius-lg);
  background: var(--surface);
}
.feature-group summary {
  position: relative;
  padding: 28px 72px 28px 32px;
  cursor: pointer;
  list-style: none;
}
.feature-group summary::-webkit-details-marker {
  display: none;
}
.feature-group summary::after {
  content: "+";
  position: absolute;
  top: 30px;
  right: 30px;
  color: var(--brand-600);
  font-size: 28px;
  line-height: 1;
}
.feature-group[open] summary::after {
  content: "\2212";
}
.feature-group-title {
  display: block;
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.35;
}
.feature-group-description {
  display: block;
  margin-top: 8px;
  color: var(--text-secondary);
  font-size: 15px;
}
.feature-group .grid {
  padding: 0 24px 24px;
  gap: 12px;
}
.feature-group .card {
  padding: 24px;
  border-radius: 16px;
}
.feature-group .card h3 {
  font-size: 18px;
}

/* Four decisions, kept in a simple sequence. */
.steps {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 32px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}
.steps li {
  min-width: 0;
  counter-increment: step;
}
.steps li::before {
  content: counter(step, decimal-leading-zero);
  display: block;
  margin-bottom: 24px;
  color: var(--brand-600);
  font-size: 38px;
  font-weight: 400;
  letter-spacing: -0.05em;
  line-height: 1;
}
.steps h3 {
  font-size: 20px;
  line-height: 1.3;
}
.steps p {
  margin-top: 14px;
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.7;
}
.trust {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 48px 80px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.trust li {
  min-width: 0;
}
.trust h3 {
  font-size: 24px;
}
.trust p {
  margin-top: 16px;
  color: var(--text-secondary);
  font-size: 17px;
}

/* Installation guide: overview, commands, then a navigable reference. */
.page-head {
  padding: clamp(64px, 7vw, 100px) 0 64px;
  text-align: center;
}
.page-head h1 {
  font-size: clamp(40px, 5.5vw, 72px);
  line-height: 1.1;
}
.page-head .lead {
  max-width: 620px;
  margin: 24px auto 0;
  color: var(--text-secondary);
  font-size: 20px;
}
.setup-overview {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px 32px;
  margin: 36px 0 0;
  padding: 0;
  list-style: none;
}
.setup-overview a {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  font-size: 14px;
  color: var(--text-secondary);
  text-decoration: none;
}
.setup-overview a:hover {
  color: var(--brand-700);
}
.setup-overview span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--sunken);
  color: var(--brand-600);
  font-size: 11px;
  font-weight: 600;
}
.guide-layout {
  display: grid;
  grid-template-columns: 200px minmax(0, 1fr);
  align-items: start;
  gap: 80px;
}
.guide-toc {
  position: sticky;
  top: 108px;
  display: flex;
  flex-direction: column;
  padding: 12px 0;
}
.guide-toc p {
  margin-bottom: 12px;
  color: var(--text);
  font-size: 13px;
  font-weight: 600;
}
.guide-toc a {
  display: flex;
  align-items: center;
  min-height: 44px;
  color: var(--text-secondary);
  font-size: 14px;
  text-decoration: none;
}
.guide-toc a:hover {
  color: var(--brand-700);
  text-decoration: underline;
}
.prose {
  min-width: 0;
  max-width: 800px;
}
.prose h2 {
  margin-top: 64px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-size: clamp(26px, 3vw, 34px);
}
.prose h2:first-child {
  margin-top: 0;
  padding-top: 0;
  border: 0;
}
.prose h3 {
  margin-top: 32px;
}
.prose p,
.prose ul,
.prose ol,
.prose pre {
  margin-top: 18px;
}
.prose p,
.prose li {
  color: var(--text-secondary);
}
.prose li + li {
  margin-top: 12px;
}
.prose .setup-steps > li + li {
  margin-top: 32px;
}
.prose pre code {
  font-size: inherit;
}
.prose pre {
  overflow-x: auto;
  padding: 22px 24px;
  border-radius: var(--radius-md);
  background: #172b23;
  color: var(--text-inverse);
  font-size: 14px;
  line-height: 1.7;
}
.notice {
  padding: 20px 24px;
  border-radius: var(--radius-md);
  background: var(--warning-bg);
  color: var(--text);
}

/* Real app screens, with room for their explanations. */
.shots {
  display: grid;
  gap: 88px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.shot {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
  align-items: center;
  gap: 52px;
  min-width: 0;
  margin: 0;
}
.shot a {
  display: block;
  padding: 12px;
  border-radius: 24px;
  background: var(--sunken);
}
.shot img {
  width: 100%;
  height: auto;
  border: 1px solid rgb(0 0 0 / 5%);
  border-radius: 14px;
  background: var(--surface);
  box-shadow: var(--shadow);
}
.shots > li:nth-child(even) .shot {
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.6fr);
}
.shots > li:nth-child(even) .shot a {
  grid-column: 2;
  grid-row: 1;
}
.shots > li:nth-child(even) .shot figcaption {
  grid-column: 1;
  grid-row: 1;
}
.shot figcaption {
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.7;
}
.shot figcaption strong {
  display: block;
  margin-bottom: 18px;
  color: var(--text);
  font-size: clamp(24px, 2.6vw, 34px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

/* FAQ */
.faq {
  max-width: 820px;
  margin: 0 auto;
}
.faq h2 {
  margin-bottom: 28px;
}
.faq details {
  border-bottom: 1px solid var(--border);
}
.faq summary {
  position: relative;
  min-height: 64px;
  padding: 24px 40px 24px 0;
  font-size: 18px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}
.faq summary::-webkit-details-marker {
  display: none;
}
.faq summary::after {
  content: "+";
  position: absolute;
  right: 8px;
  top: 20px;
  color: var(--brand-600);
  font-size: 24px;
  font-weight: 400;
}
.faq details[open] summary::after {
  content: "\2212";
}
.faq details > p {
  padding-bottom: 18px;
  color: var(--text-secondary);
}
.faq details > p + p {
  margin-top: -6px;
}

/* Footer */
.site-footer {
  padding: 64px 0 40px;
  border-top: 1px solid var(--border);
  background: var(--sunken);
  color: var(--text-secondary);
  font-size: 15px;
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 180px), 1fr));
  gap: 28px 32px;
}
.footer-brand img {
  width: auto;
  height: 30px;
}
.footer-col h2 {
  margin-bottom: 10px;
  color: var(--text);
  font-size: 14px;
  font-weight: 650;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.footer-col ul {
  margin: 0;
  padding: 0;
  list-style: none;
}
.footer-col li + li {
  margin-top: 6px;
}
.footer-col a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--text-secondary);
}
/* A contact column whose generated links are all still empty is hidden. */
.footer-col:not(:has(a)) {
  display: none;
}
.footer-col li:empty {
  display: none;
}
.disclaimer {
  margin-top: 36px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.7;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

kbd {
  padding: 1px 6px;
  border: 1px solid var(--border-strong);
  border-bottom-width: 2px;
  border-radius: var(--radius-sm);
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 0.85em;
}

/* Language switch */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 14px;
  font-weight: 550;
  color: var(--text-muted);
}
.lang-switch a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  min-width: 44px;
  color: var(--text-secondary);
  text-decoration: none;
}
.lang-switch a:hover {
  color: var(--brand-700);
}
.lang-switch a[aria-current="true"] {
  color: var(--brand-700);
}
.lang-switch .sep {
  color: var(--border-strong);
  user-select: none;
}

/* Traditional Chinese: CJK system font fallback (no remote fonts; CSP font-src 'self') */
html[lang="zh-Hant-TW"] {
  --font-sans: "DM Sans", "PingFang TC", "Noto Sans TC", "Microsoft JhengHei",
    "Heiti TC", system-ui, -apple-system, sans-serif;
}

/* The same flow, from a narrow phone to a wide desktop. */
@media (max-width: 900px) {
  .site-header .wrap {
    gap: 16px;
  }
  .site-nav ul {
    gap: 16px;
  }
  .steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 40px;
  }
  .shot,
  .shots > li:nth-child(even) .shot {
    gap: 32px;
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
  }
  .guide-layout {
    grid-template-columns: 170px minmax(0, 1fr);
    gap: 40px;
  }
}
@media (max-width: 700px) {
  .site-header .wrap {
    gap: 12px;
    min-height: 64px;
  }
  .brand img {
    width: 92px;
  }
  .site-nav {
    display: none;
  }
  .lang-switch {
    margin-left: auto;
  }
  .lang-switch [aria-current="true"],
  .lang-switch .sep {
    display: none;
  }
  .nav-cta {
    padding: 9px 14px;
    font-size: 12px;
  }
  .hero {
    padding-top: 52px;
    padding-bottom: 48px;
  }
  .hero h1 {
    font-size: clamp(38px, 7.5vw, 52px);
    letter-spacing: -0.045em;
  }
  .hero .lead {
    max-width: 29em;
    font-size: 18px;
  }
  .hero-actions {
    gap: 8px 20px;
    margin-top: 26px;
  }
  .hero-note {
    font-size: 12px;
  }
  .product-window {
    border-radius: 12px;
  }
  .window-bar {
    min-height: 28px;
    padding: 0 12px;
    font-size: 9px;
  }
  .window-state {
    visibility: hidden;
  }
  .window-dots i {
    width: 5px;
    height: 5px;
  }
  .hero-product figcaption {
    max-width: 26em;
    margin: 20px auto 0;
    font-size: 12px;
  }
  .section-head p {
    font-size: 17px;
  }
  .grid,
  .trust {
    grid-template-columns: minmax(0, 1fr);
  }
  .card {
    padding: 28px;
  }
  .trust {
    gap: 36px;
  }
  .feature-group summary {
    padding: 24px 52px 24px 24px;
  }
  .feature-group summary::after {
    top: 27px;
    right: 22px;
  }
  .feature-group-title {
    font-size: 21px;
  }
  .feature-group .grid {
    padding: 0 16px 16px;
  }
  .shots {
    gap: 56px;
  }
  .shot,
  .shots > li:nth-child(even) .shot {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 24px;
  }
  .shot a {
    padding: 8px;
    border-radius: 18px;
  }
  .shot img {
    border-radius: 10px;
  }
  .shot figcaption strong {
    margin-bottom: 12px;
  }
  .page-head .lead {
    font-size: 18px;
  }
  .setup-overview {
    flex-direction: column;
    align-items: center;
    gap: 4px;
    margin-top: 28px;
  }
  .setup-overview li {
    min-width: 220px;
    text-align: left;
  }
  .guide-layout {
    grid-template-columns: minmax(0, 1fr);
    gap: 40px;
  }
  .guide-toc {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 16px;
    padding: 24px;
    border-radius: 20px;
    background: var(--sunken);
  }
  .guide-toc p {
    grid-column: 1 / -1;
  }
  .guide-toc a {
    font-size: 13px;
  }
  .prose pre {
    padding: 18px;
    font-size: 13px;
  }
  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .footer-brand {
    grid-column: 1 / -1;
  }
}
@media (max-width: 420px) {
  .brand img {
    width: 84px;
  }
  .site-header .wrap {
    gap: 8px;
  }
  .steps {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }
  .steps li::before {
    margin-bottom: 16px;
    font-size: 32px;
  }
  .steps p {
    margin-top: 10px;
  }
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .button,
  .install-tab {
    transition: none;
  }
}