/* pdf-encrypt — "one motif": the vermilion seal runs the whole system.
   Ground: bone. Ink: 墨 black. Accent: 印泥 vermilion. */

:root {
  --bg: #ecebe7;
  --surface: #e1dfd9;
  --ink: #1d1c1a;
  --muted: #55524b;
  --seal: #c3161f;
  --seal-text: #a8101a;
  --on-seal: #ffffff;
  --prompt: #ff6b66;
  --night: #1d1c1a;
  --on-night: #ecebe7;
  --on-night-muted: #bdb7ab;
  --code-bg: #1d1c1a;
  --code-ink: #ecebe7;
  --field-line: #8f8a80;

  --f-install: #ecebe7;
  --f-builder: #e1dfd9;
  --f-features: #d6d3cb;
  --f-reference: #c9c4b9;
  --f-faq: #3b3834;
  --tile-light: #ecebe7;
  --tile-dark: #1d1c1a;
  --sheet-front: #c9c4b9;
  --sheet-back: #6f6a61;

  --font: "General Sans", "PingFang TC", "Noto Sans TC", "Microsoft JhengHei", system-ui, sans-serif;
  --mono: ui-monospace, "SF Mono", "Cascadia Code", Menlo, Consolas, monospace; /* taste-skill-ignore: used only by <code>/<pre> */

  --step-small: clamp(0.8125rem, 0.79rem + 0.1vw, 0.875rem);
  --step-body: clamp(1.0625rem, 1rem + 0.25vw, 1.1875rem);
  --step-lead: clamp(1.375rem, 1rem + 1.3vw, 2.25rem);
  --step-head: clamp(2.5rem, 1.4rem + 4.4vw, 6rem);
  --step-display: clamp(3.5rem, 0.6rem + 8.4vw, 9.5rem);

  --margin: clamp(16px, 2.6vw, 32px);
  --section: clamp(96px, 12vw, 200px);
  --ease-out: cubic-bezier(0.2, 0.7, 0.2, 1);
  --t-hover: 160ms;
  --t-ui: 240ms;
  --t-enter: 640ms;

  color-scheme: light;
}

:root[data-theme="dark"] {
  --bg: #161513;
  --surface: #1e1c1a;
  --ink: #ecebe7;
  --muted: #b3ada2;
  --seal-text: #ff6b66;
  --night: #0c0b0a;
  --code-bg: #0c0b0a;
  --field-line: #6f6a61;
  --f-install: #262420;
  --f-builder: #1f1d1a;
  --f-features: #2a2723;
  --f-reference: #2d2a26;
  --f-faq: #3b3834;
  --tile-light: #3b3834;
  --tile-dark: #0e0d0c;
  --sheet-front: #3b3834;
  --sheet-back: #2a2723;
  color-scheme: dark;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 76px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: var(--step-body);
  line-height: 1.55;
  overflow-x: hidden;
}

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

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

ul[role="list"],
ol {
  list-style: none;
  padding: 0;
}

h1,
h2 {
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 0.98;
  text-wrap: balance;
}

h2 {
  font-size: var(--step-head);
}

code,
pre {
  font-family: var(--mono);
}

p code,
li code,
label code,
span code,
dd code {
  font-size: var(--step-small);
  overflow-wrap: anywhere;
}

a {
  color: var(--seal-text);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
  transition: color var(--t-hover) ease;
}

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

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

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

.skip-link {
  position: absolute;
  left: var(--margin);
  top: -100px;
  z-index: 50;
  padding: 12px 18px;
  background: var(--seal);
  color: var(--on-seal);
}

.skip-link:focus {
  top: 12px;
}

.visually-hidden,
.svg-defs {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* ---------- Buttons ---------- */

.button {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 12px 22px;
  border: 0;
  border-radius: 0;
  background: var(--seal);
  color: var(--on-seal);
  font: 500 var(--step-body) / 1.2 var(--font);
  text-decoration: none;
  cursor: pointer;
  transition: transform var(--t-hover) var(--ease-out), background-color var(--t-hover) ease;
}

.button::before {
  content: "";
  width: 0.5em;
  height: 0.5em;
  background: currentColor;
}

.button:hover {
  color: var(--on-seal);
  transform: translateY(-2px);
}

.button:active {
  transform: translateY(0) scale(0.98);
}

.button-small {
  min-height: 40px;
  padding: 8px 16px;
  font-size: var(--step-small);
}

.button-on-seal {
  background: var(--night);
  color: var(--on-night);
}

.button-on-seal:hover {
  color: var(--on-night);
}

.copy-button,
.text-action,
.theme-toggle {
  border: 0;
  border-radius: 0;
  font: 500 var(--step-small) / 1.2 var(--font);
  cursor: pointer;
  transition: transform var(--t-hover) var(--ease-out), background-color var(--t-hover) ease, color var(--t-hover) ease;
}

.copy-button {
  min-height: 44px;
  padding: 10px 16px;
  background: var(--ink);
  color: var(--bg);
}

.copy-button:hover {
  background: var(--seal);
  color: var(--on-seal);
}

.copy-button:active,
.text-action:active,
.theme-toggle:active {
  transform: scale(0.97);
}

.text-action {
  padding: 8px 0;
  background: none;
  color: var(--seal-text);
  font-size: var(--step-body);
  text-decoration: underline;
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

.text-action:hover {
  color: var(--ink);
}

.code-block {
  margin: 0;
  padding: 16px 20px;
  overflow-x: auto;
  background: var(--code-bg);
  color: var(--code-ink);
  font-size: var(--step-small);
  line-height: 1.6;
}

/* ---------- Hero field: night ground, the giant seal, the folder stack ---------- */

.hero-field {
  position: relative;
  overflow: hidden;
  background: var(--night);
  color: var(--on-night);
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  gap: clamp(16px, 2.4vw, 40px);
  min-height: 60px;
  padding: 8px var(--margin);
  background: var(--night);
  color: var(--on-night);
}

.wordmark {
  display: inline-flex;
  flex: none;
  align-items: center;
  gap: 10px;
  color: var(--on-night);
  font-weight: 700;
  font-size: var(--step-body);
  letter-spacing: -0.01em;
  text-decoration: none;
}

.wordmark:hover {
  color: var(--on-night);
}

.seal-mark {
  width: 26px;
  height: 26px;
  color: var(--seal);
}

.site-nav {
  flex: 1 1 auto;
  min-width: 0;
}

.nav-list {
  display: flex;
  justify-content: center;
  gap: clamp(14px, 2vw, 28px);
}

.nav-list a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  color: var(--on-night-muted);
  font-size: var(--step-small);
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--t-hover) ease;
}

.nav-list a::before {
  content: "";
  width: 0.5em;
  height: 0.5em;
  background: var(--seal);
  opacity: 0;
  transform: scale(0.96);
  transition: opacity var(--t-ui) ease, transform var(--t-ui) var(--ease-out);
}

.nav-list a:hover,
.nav-list a[aria-current="location"] {
  color: var(--on-night);
}

.nav-list a[aria-current="location"]::before {
  opacity: 1;
  transform: scale(1);
}

.topbar-actions {
  display: flex;
  flex: none;
  align-items: center;
  gap: 8px;
}

.topbar-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding-inline: 8px;
  color: var(--on-night);
  font-size: var(--step-small);
}

.topbar-link:hover {
  color: var(--seal);
}

.nav-toggle {
  display: none;
  min-height: 44px;
  padding: 8px 14px;
  border: 0;
  border-radius: 0;
  background: var(--seal);
  color: var(--on-seal);
  font: 500 var(--step-small) / 1.2 var(--font);
  cursor: pointer;
  transition: transform var(--t-hover) var(--ease-out);
}

.nav-toggle:active {
  transform: scale(0.97);
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  color: var(--on-night);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

.theme-toggle .theme-off {
  fill: var(--on-night-muted);
  opacity: 0.45;
}

.theme-toggle .theme-on {
  fill: currentColor;
  transition: transform var(--t-ui) var(--ease-out);
  transform-origin: 10px 10px;
}

.theme-toggle[aria-pressed="true"] .theme-on {
  transform: translateX(8px);
}

.theme-toggle:hover {
  color: var(--seal);
}

.hero {
  position: relative;
  min-height: clamp(380px, 52svh, 620px);
  padding: clamp(40px, 9svh, 110px) var(--margin) 48px;
}

.hero-seal {
  position: absolute;
  z-index: 0;
  top: clamp(-60px, -4svh, 0px);
  right: -9vw;
  width: min(50vw, 92svh);
  height: auto;
  color: var(--seal);
  animation: seal-breathe 14s ease-in-out infinite alternate;
  transform-origin: 60% 40%;
}

@keyframes seal-breathe {
  from { transform: rotate(-2.5deg) translateY(0); }
  to { transform: rotate(1.5deg) translateY(14px); }
}

.hero-copy {
  position: relative;
  z-index: 1;
  max-width: 52vw;
}

.hero h1 {
  font-size: var(--step-display);
  line-height: 0.9;
  letter-spacing: -0.035em;
  white-space: nowrap;
}

.hero-statement {
  max-width: 21em;
  margin-top: clamp(20px, 3vh, 36px);
  font-size: var(--step-lead);
  line-height: 1.35;
  color: var(--on-night);
}

.hero-action {
  margin-top: clamp(20px, 3vh, 32px);
}

.folder-front {
  position: relative;
  z-index: 2;
  width: 86%;
  margin: 96px auto 0;
  background: var(--f-install);
  color: var(--ink);
}

/* Two sheets behind the open folder: the stack it was pulled from. */
.folder-front::before,
.folder-front::after {
  content: "";
  position: absolute;
  bottom: 100%;
  height: 14px;
}

.folder-front::before {
  left: 2%;
  right: 2%;
  background: var(--sheet-front);
}

.folder-front::after {
  left: 4%;
  right: 4%;
  bottom: calc(100% + 14px);
  background: var(--sheet-back);
}

.folder-tab {
  position: absolute;
  z-index: 1;
  right: 6%;
  bottom: 100%;
  display: inline-flex;
  align-items: center;
  height: 44px;
  padding: 0 32px;
  background: var(--f-install);
  color: var(--ink);
  font-size: var(--step-body);
  font-weight: 700;
  white-space: nowrap;
  clip-path: polygon(14px 0, calc(100% - 14px) 0, 100% 100%, 0 100%);
}

.install-inner {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: clamp(32px, 5vw, 80px);
  padding: clamp(32px, 5vw, 72px) clamp(20px, 4vw, 64px) clamp(48px, 7vw, 96px);
}

.install-head h2 {
  width: fit-content;
  font-size: var(--step-head);
}

.install-head p {
  max-width: 34em;
  margin: 20px 0 28px;
}

.tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 16px;
}

.tab-list [role="tab"] {
  min-height: 44px;
  padding: 10px 16px;
  border: 0;
  border-radius: 0;
  background: var(--surface);
  color: var(--ink);
  font: 500 var(--step-small) / 1.2 var(--font);
  cursor: pointer;
  transition: background-color var(--t-hover) ease, color var(--t-hover) ease, transform var(--t-hover) var(--ease-out);
}

.tab-list [role="tab"]:hover {
  transform: translateY(-2px);
}

.tab-list [role="tab"][aria-selected="true"] {
  background: var(--ink);
  color: var(--bg);
}

.tab-panel > p {
  margin-top: 16px;
  max-width: 60ch;
}

.snippet {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
}

.snippet .code-block {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.snippet .copy-button {
  justify-self: start;
}

.download-list {
  display: grid;
  gap: 12px;
  padding: 0;
  list-style: none;
}

.download-list li {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.download-list li::before,
.row-name::before,
.messages li::before {
  content: "";
  flex: none;
  width: 0.6em;
  height: 0.6em;
  background: var(--seal);
}

/* ---------- Stages as one bar ---------- */

.stages {
  padding: var(--section) var(--margin) clamp(64px, 8vw, 120px);
}

.stages h2 {
  margin-bottom: 64px;
}

.stage-bar {
  display: flex;
  gap: 6px;
  min-height: 200px;
  margin: 0;
}

.stage {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 16px;
  min-width: 0;
  padding: 20px;
}

.stage-install { flex: 0 0 14%; background: var(--night); color: var(--on-night); }
.stage-compose { flex: 1 1 auto; background: var(--seal); color: var(--on-seal); }
.stage-run { flex: 0 0 14%; background: var(--f-reference); color: var(--ink); }
:root[data-theme="dark"] .stage-run { background: var(--tile-light); color: var(--ink); }
:root[data-theme="dark"] .stage-install { background: var(--tile-dark); }

.stage-time {
  font-size: var(--step-lead);
  font-weight: 700;
  line-height: 1.1;
}

.stage-text {
  max-width: 22ch;
}

.stages-note {
  max-width: 60ch;
  margin-top: 28px;
  color: var(--muted);
}

/* ---------- Showcase: the scenario index on the seal ---------- */

.showcase {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  align-items: end;
  gap: clamp(32px, 4vw, 64px);
  min-height: min(100svh, 1000px);
  padding: clamp(64px, 8vw, 120px) var(--margin) var(--section);
}

.showcase-heading {
  margin-bottom: 8px;
  color: var(--muted);
  font-size: var(--step-lead);
  font-weight: 500;
  letter-spacing: -0.01em;
  line-height: 1.15;
}

.scenario-list {
  display: grid;
}

.scenario {
  display: flex;
  align-items: center;
  gap: 0.4em;
  width: 100%;
  padding: 4px 0;
  border: 0;
  background: none;
  color: var(--muted);
  font: 500 var(--step-lead) / 1.15 var(--font);
  letter-spacing: -0.01em;
  text-align: left;
  cursor: pointer;
  transition: color var(--t-ui) ease, transform var(--t-ui) var(--ease-out);
}

.scenario::before {
  content: "";
  flex: none;
  width: 0.42em;
  height: 0.42em;
  background: var(--seal);
  opacity: 0;
  transform: scale(0.96);
  transition: opacity var(--t-ui) ease, transform var(--t-ui) var(--ease-out);
}

.scenario[aria-pressed="true"],
.scenario.is-preview {
  color: var(--ink);
}

.scenario[aria-pressed="true"]::before {
  opacity: 1;
  transform: scale(1);
}

.scenario:hover {
  transform: translateX(6px);
}

.showcase-stage {
  position: relative;
  display: grid;
  justify-items: center;
  align-content: end;
  gap: 20px;
  padding-top: clamp(40px, 6vw, 80px);
}

.stage-art {
  display: grid;
  place-items: center;
  width: 100%;
}

.stage-seal,
.terminals {
  grid-area: 1 / 1;
}

.stage-seal {
  width: min(100%, 60svh, 580px);
  height: auto;
  color: var(--seal);
}

.terminals {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  width: min(88%, 540px);
  transform: translate(clamp(16px, 6%, 56px), clamp(16px, 7%, 56px));
}

.terminal {
  grid-area: 1 / 1;
  margin: 0;
  background: var(--night);
  color: var(--on-night);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--t-ui) ease, visibility 0s linear var(--t-ui);
}

.terminal.is-on {
  opacity: 1;
  visibility: visible;
  transition: opacity var(--t-ui) ease, visibility 0s;
}

.terminal pre {
  margin: 0;
  padding: clamp(18px, 2.4vw, 28px);
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  font-size: var(--step-small);
  line-height: 1.65;
}

.t-prompt {
  color: var(--prompt);
}

.scenario-fact {
  justify-self: stretch;
  max-width: 40em;
  font-size: var(--step-body);
}

.text-action {
  justify-self: start;
}

/* ---------- Builder ---------- */

.builder-section {
  padding: var(--section) var(--margin);
  background: var(--f-builder);
}

.builder-head {
  max-width: 920px;
  margin-bottom: clamp(40px, 5vw, 72px);
}

.builder-head p {
  max-width: 44em;
  margin-top: 24px;
}

.builder {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: clamp(32px, 4vw, 64px);
  align-items: start;
}

.builder-form fieldset {
  min-width: 0;
  margin: 0 0 36px;
  padding: 0;
  border: 0;
}

.builder-form legend {
  margin-bottom: 12px;
  padding: 0;
  font-size: var(--step-body);
  font-weight: 700;
}

.segmented,
.checks,
.permission-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.segmented label,
.checks label,
.permission-grid label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 8px 14px;
  background: var(--bg);
  cursor: pointer;
  transition: background-color var(--t-hover) ease, color var(--t-hover) ease;
}

.segmented label:has(input:checked) {
  background: var(--ink);
  color: var(--bg);
}

.segmented label:hover,
.checks label:hover,
.permission-grid label:hover {
  background: var(--surface);
}

.segmented label:has(input:checked):hover {
  background: var(--ink);
}

:root[data-theme="dark"] .segmented label:hover,
:root[data-theme="dark"] .checks label:hover,
:root[data-theme="dark"] .permission-grid label:hover {
  background: var(--f-reference);
}

input[type="radio"],
input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin: 0;
  accent-color: var(--seal);
}

.checks,
.permission-grid,
.password-row,
.field,
.hint,
.metadata-grid {
  margin-top: 12px;
}

.field {
  display: grid;
  gap: 6px;
}

.field label {
  font-weight: 500;
}

input[type="text"],
input[type="password"],
input[type="url"],
select {
  width: 100%;
  min-height: 46px;
  padding: 10px 12px;
  border: 1px solid var(--field-line);
  border-radius: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 1rem / 1.3 var(--font);
}

input:disabled {
  opacity: 0.55;
}

.password-row {
  display: grid;
  grid-template-columns: minmax(150px, auto) minmax(0, 1fr);
  align-items: center;
  gap: 12px;
}

.password-row label,
.metadata-row label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  cursor: pointer;
}

.hint {
  max-width: 60ch;
  color: var(--muted);
  font-size: var(--step-small);
}

.metadata-grid {
  display: grid;
  gap: 8px;
}

.metadata-row {
  display: grid;
  grid-template-columns: 170px minmax(0, 1fr);
  align-items: center;
  gap: 12px;
}

.output-sticky {
  position: sticky;
  top: 24px;
  display: grid;
  gap: 16px;
}

.output-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.output-head h3 {
  font-size: var(--step-body);
  font-weight: 700;
}

.output-code {
  min-height: 160px;
  white-space: pre;
}

.messages {
  display: grid;
  gap: 10px;
  padding: 0;
  list-style: none;
}

.messages li {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.messages li strong {
  flex: none;
  font-weight: 700;
}

.messages .is-error {
  color: var(--seal-text);
}

.messages .is-note::before {
  background: var(--muted);
}

.messages .is-warning::before {
  background: var(--ink);
}

/* ---------- Features: specimens on colour tiles ---------- */

.features {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 9fr);
  gap: clamp(32px, 4vw, 64px);
  padding: var(--section) var(--margin);
  background: var(--f-features);
}

.features-head p {
  max-width: 30ch;
  margin-top: 24px;
}

.features-head h2 {
  font-size: var(--step-lead);
  line-height: 1.1;
}

.specimens {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 40px 10px;
}

.specimen-wide {
  grid-column: span 2;
}

.specimen-tile {
  display: grid;
  place-items: center;
  aspect-ratio: 4 / 5;
  margin-bottom: 16px;
  overflow: hidden;
}

.specimen-wide .specimen-tile {
  aspect-ratio: 8 / 5;
}

.specimen-tile img {
  width: 100%;
  height: 70%;
  object-fit: contain;
  transition: transform 600ms var(--ease-out);
}

.specimen:hover .specimen-tile img {
  transform: scale(1.05) rotate(-2deg);
}

.tile-seal { background: var(--seal); }
.tile-ink { background: var(--tile-dark); }
.tile-stone { background: var(--tile-light); }

.specimen h3 {
  font-size: var(--step-body);
  font-weight: 700;
}

.specimen p {
  margin-top: 4px;
  color: var(--muted);
  font-size: var(--step-small);
}

/* ---------- Reference: two-ended rows ---------- */

.reference {
  display: grid;
  grid-template-columns: 18% minmax(0, 560px) minmax(0, 1fr);
  gap: clamp(32px, 4vw, 64px);
  align-items: center;
  padding: var(--section) var(--margin);
  background: var(--f-reference);
}

:root[data-theme="dark"] .reference {
  --ink: #1d1c1a;
  --muted: #55524b;
  --seal-text: #a8101a;
  background: #ecebe7;
  color: var(--ink);
}

.reference-list {
  grid-column: 2;
}

.reference h2 {
  margin-bottom: 32px;
  font-size: var(--step-lead);
  font-weight: 500;
}

.ref-group {
  margin: 40px 0 6px;
  color: var(--muted);
  font-size: var(--step-body);
  font-weight: 500;
}

.reference h2 + .ref-group {
  margin-top: 0;
}

.rows {
  display: grid;
}

.row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  min-height: 38px;
  padding-block: 6px;
}

.row-name {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.row-value {
  flex: none;
  color: var(--muted);
  font-size: var(--step-small);
  font-variant-numeric: tabular-nums;
}

.reference-figure {
  grid-column: 3;
}

.reference-figure img {
  width: 100%;
  height: auto;
}

/* ---------- FAQ: tabbed index cards ---------- */

.faq {
  padding: var(--section) var(--margin);
  background: var(--f-faq);
  color: var(--on-night);
}

.faq h2 {
  max-width: 66%;
  margin: 0 auto clamp(72px, 7vw, 104px);
}

.cards {
  max-width: 66%;
  margin-inline: auto;
}

.card {
  --tab-step: 150px;
  --tab-width: 200px;
  position: relative;
  margin-top: 40px;
  background: var(--card-bg, var(--bg));
  color: var(--card-ink, var(--ink));
}

.card:nth-child(3n + 2) { --card-bg: var(--surface); }
.card:nth-child(3n) { --card-bg: var(--f-features); }
.card:nth-child(1) { --i: 0; }
.card:nth-child(2) { --i: 1; }
.card:nth-child(3) { --i: 2; }
.card:nth-child(4) { --i: 3; }
.card:nth-child(5) { --i: 4; }

.card h3 {
  font-size: inherit;
}

.card-toggle {
  display: block;
  width: 100%;
  min-height: 72px;
  padding: 22px 28px;
  border: 0;
  background: none;
  color: inherit;
  font: 500 var(--step-body) / 1.35 var(--font);
  text-align: left;
  cursor: pointer;
}

.card-tab {
  position: absolute;
  bottom: 100%;
  left: calc(var(--i) * min(var(--tab-step), (100% - var(--tab-width)) / 4));
  display: inline-flex;
  align-items: center;
  width: var(--tab-width);
  height: 40px;
  padding: 0 24px;
  background: var(--card-bg, var(--bg));
  font-size: var(--step-small);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 100%, 0 100%);
  transition: transform var(--t-hover) var(--ease-out);
}

.card-toggle:hover .card-tab {
  transform: translateY(-4px);
}

.card-q {
  display: block;
}

.card-body {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 320ms var(--ease-out);
}

.card-body > div {
  overflow: hidden;
}

.card-body p {
  max-width: 50ch;
  padding: 0 28px 28px;
}

.card.is-open .card-body {
  grid-template-rows: 1fr;
}

/* ---------- Footer: the seal built large ---------- */

.site-footer {
  padding: clamp(64px, 8vw, 120px) var(--margin) 32px;
  background: var(--seal);
  color: var(--on-seal);
}

.site-footer a {
  color: var(--on-seal);
}

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

.footer-mark {
  display: flex;
  align-items: flex-end;
  gap: clamp(20px, 3vw, 48px);
  min-height: min(34svh, 340px);
}

.block-seal {
  flex: none;
  width: min(34svh, 36vw, 320px);
  height: auto;
  fill: var(--night);
}

.footer-name {
  font-size: var(--step-display);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 0.8;
  white-space: nowrap;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 32px;
  margin-top: 56px;
}

.footer-links h2 {
  margin-bottom: 10px;
  font-size: var(--step-body);
  font-weight: 700;
  letter-spacing: 0;
}

.footer-links ul {
  display: grid;
  gap: 6px;
  font-size: var(--step-small);
}

.footer-last {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-top: 56px;
}

.footer-last p {
  max-width: 70ch;
  font-size: var(--step-small);
}

/* ---------- Toast ---------- */

.toast {
  position: fixed;
  left: 50%;
  bottom: max(20px, env(safe-area-inset-bottom));
  z-index: 60;
  padding: 12px 18px;
  background: var(--night);
  color: var(--on-night);
  font-size: var(--step-small);
  opacity: 0;
  transform: translate(-50%, 12px);
  pointer-events: none;
  transition: opacity var(--t-ui) ease, transform var(--t-ui) var(--ease-out);
}

.toast.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* ---------- Entrances ---------- */

.js .reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--t-enter) var(--ease-out), transform var(--t-enter) var(--ease-out);
  transition-delay: var(--delay, 0ms);
}

.js .reveal.is-in,
.reveal-all .reveal {
  opacity: 1;
  transform: none;
}

/* ---------- Narrow screens ---------- */

@media (max-width: 880px) {
  html {
    scroll-padding-top: 112px;
  }

  .topbar {
    flex-wrap: wrap;
    row-gap: 0;
    padding-bottom: 0;
  }

  .topbar-actions {
    margin-left: auto;
  }

  .site-nav {
    order: 3;
    flex-basis: 100%;
    margin-inline: calc(-1 * var(--margin));
    overflow-x: auto;
    scrollbar-width: none;
    scroll-snap-type: x proximity;
  }

  .site-nav::-webkit-scrollbar {
    display: none;
  }

  .nav-list {
    justify-content: flex-start;
    width: max-content;
    padding-inline: var(--margin);
  }

  .nav-list a {
    scroll-snap-align: start;
  }
}

/* Phone: the nav folds behind a 目錄 button so the sticky bar stays one row. */
@media (max-width: 720px) {
  html {
    scroll-padding-top: 76px;
  }

  .topbar {
    padding-bottom: 8px;
  }

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

  .topbar-link {
    display: none;
  }

  .site-nav {
    display: none;
    margin-inline: 0;
    overflow: visible;
  }

  .topbar.is-open .site-nav {
    display: block;
    padding-block: 8px 16px;
  }

  .nav-list {
    flex-direction: column;
    gap: 0;
    width: auto;
    padding-inline: 0;
  }

  .nav-list a {
    min-height: 52px;
    color: var(--on-night);
    font-size: var(--step-lead);
  }
}

@media (max-width: 960px) {
  .install-inner,
  .builder,
  .features {
    grid-template-columns: minmax(0, 1fr);
  }

  .output-sticky {
    position: static;
  }

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

  .reference-list,
  .reference-figure {
    grid-column: 1;
  }

  .reference-figure {
    max-width: 560px;
  }

  .faq h2,
  .cards {
    max-width: none;
  }
}

@media (max-width: 720px) {
  .hero {
    min-height: 0;
    padding-top: calc(62vw + 8px);
  }

  .hero-seal {
    top: -6vw;
    right: -12vw;
    width: 74vw;
  }

  .hero-copy {
    max-width: none;
  }

  .folder-front {
    width: 100%;
    margin-top: 80px;
  }

  .folder-front::before { left: 3%; right: 3%; }
  .folder-front::after { left: 6%; right: 6%; }

  .folder-tab {
    right: 4%;
    height: 40px;
    padding: 0 24px;
  }

  .install-head .button {
    width: 100%;
    justify-content: center;
  }

  .stage-bar {
    flex-direction: column;
    min-height: 0;
  }

  .stage {
    flex: none;
    min-height: 120px;
  }

  .stage-compose {
    min-height: 260px;
  }

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

  .showcase-stage {
    order: -1;
    padding-top: 0;
  }

  .stage-seal {
    width: 86vw;
  }

  .terminals {
    width: 90%;
    transform: translate(4%, 10%);
  }

  .scenario-list {
    display: flex;
    gap: 24px;
    overflow-x: auto;
    padding-bottom: 8px;
    scroll-snap-type: x mandatory;
  }

  .scenario {
    flex: none;
    width: auto;
    white-space: nowrap;
    scroll-snap-align: start;
  }

  .scenario:hover {
    transform: none;
  }

  .password-row,
  .metadata-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

  .specimens {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px 8px;
  }


  .card {
    --tab-step: 48px;
    --tab-width: 120px;
  }

  .card-tab {
    padding: 0 16px;
  }

  .card-toggle {
    padding: 20px;
  }

  .card-body p {
    padding: 0 20px 20px;
  }

  .footer-mark {
    flex-direction: column;
    align-items: flex-start;
    min-height: 0;
  }

  .block-seal {
    width: 40vw;
  }


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

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

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0ms !important;
  }

  .js .reveal {
    transform: none;
  }
}