/* ==========================================================================
   AI租界 (AI Enclave) — 海外家庭宽带上的 Mac mini 托管与租用
   Theme: single-ink route chart on cool paper (see the "Chart identity" block at the end)
   ========================================================================== */

:root {
  /* cool chart paper and one indigo ink */
  --bg: #EEF2F7;
  --bg-2: #E3E9F2;
  --surface: #F8FAFD;
  --line: rgba(20, 31, 84, .13);
  --line-strong: rgba(20, 31, 84, .28);
  --ink: #141F54;
  --ink-2: #3B4878;
  --ink-3: #5E6A92;
  --accent: #2438A6;
  --accent-soft: #DCE3F6;
  --accent-ink: #1B2C8F;
  --led: #1F9D6B;

  /* deep-ink panels: the quote panel, the rental card, the footer */
  --rack: #101A4A;
  --rack-2: #17235C;
  --rack-3: #1F2C6B;
  --rack-line: rgba(238, 242, 251, .16);
  --rack-text: #EEF2FB;
  --rack-text-2: #AEB8DC;

  --font: "Instrument Sans", "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-display: "Newsreader", "Noto Serif SC", "Songti SC", "STSong", serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;

  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 14px;
  --r-xl: 18px;

  --wrap: 1200px;
  --gutter: clamp(16px, 4vw, 40px);

  --ease: cubic-bezier(.22, 1, .36, 1);
  --dur: 160ms;
}

*,*::before,*::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  font-feature-settings: "tnum" 1, "cv11" 1;
  -webkit-font-smoothing: antialiased;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
p { margin: 0; }
h1,h2,h3,h4 { margin: 0; font-weight: 500; letter-spacing: -0.015em; line-height: 1.15; }
.nb { white-space: nowrap; }
button { font: inherit; color: inherit; }
fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
legend { padding: 0; }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

.wrap { width: min(var(--wrap), 100% - var(--gutter) * 2); margin-inline: auto; }

.skip {
  position: absolute; left: 16px; top: -48px; z-index: 100;
  background: var(--ink); color: #fff; padding: 10px 16px; border-radius: var(--r-sm);
}
.skip:focus { top: 16px; }

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 40px; padding: 0 16px; border-radius: var(--r-md);
  font-weight: 500; font-size: 15px; white-space: nowrap;
  border: 1px solid transparent; cursor: pointer;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease), color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.btn--ink { background: var(--ink); color: #fff; }
.btn--ink:hover { background: var(--rack); }
.btn--ghost { background: transparent; color: var(--ink); border-color: var(--line-strong); }
.btn--ghost:hover { border-color: var(--ink); background: var(--surface); }
.btn--paper { background: #fff; color: var(--ink); }
.btn--paper:hover { background: var(--bg-2); }
.btn--link { background: transparent; color: var(--ink); padding-inline: 6px; }
.btn--link:hover { color: var(--accent-ink); }
.btn--soft { background: var(--surface); color: var(--ink); border-color: var(--line); box-shadow: 0 1px 2px rgba(23,28,36,.05); }
.btn--soft:hover { border-color: var(--line-strong); box-shadow: 0 4px 14px rgba(23,28,36,.08); }
.btn__icon { width: 16px; height: 16px; fill: none; stroke: var(--ink-3); stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; transition: transform var(--dur) var(--ease), stroke var(--dur) var(--ease); }
.btn--soft:hover .btn__icon { transform: translateY(2px); stroke: var(--ink); }
.btn--lg { height: 48px; padding: 0 24px; font-size: 16px; }
.btn--block { width: 100%; }

/* --------------------------------------------------------------------------
   Nav
   -------------------------------------------------------------------------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease);
}
.nav.is-scrolled { border-bottom-color: var(--line); }
.nav__row { display: flex; align-items: center; gap: 28px; height: 68px; }
.brand { display: inline-flex; flex: none; align-items: center; gap: 10px; color: var(--ink); white-space: nowrap; }
.brand__mark { flex: none; width: 30px; height: 30px; filter: drop-shadow(0 1px 1px rgba(23,28,36,.18)); }
.brand__name { font-weight: 500; font-size: 18px; letter-spacing: -0.025em; }
.brand--light { color: #fff; }

.nav__links {
  position: relative; display: flex; gap: 2px; margin-left: 4px; padding: 4px;
  border-radius: var(--r-md); background: var(--bg-2); border: 1px solid var(--line);
}
.nav__links a {
  position: relative; z-index: 1; padding: 8px 16px; border-radius: var(--r-md); font-size: 14.5px; font-weight: 500; color: var(--ink-2);
  transition: color var(--dur) var(--ease);
}
.nav__links a:hover, .nav__links a.is-active { color: var(--ink); }
.nav__indicator {
  position: absolute; top: 4px; bottom: 4px; left: 0; width: 0; border-radius: var(--r-md);
  background: var(--surface); box-shadow: 0 1px 2px rgba(23,28,36,.10), 0 0 0 1px rgba(23,28,36,.04);
  opacity: 0; transition: left .32s var(--ease), width .32s var(--ease), opacity .2s var(--ease);
}
.nav__links.has-indicator .nav__indicator { opacity: 1; }

.nav__actions { margin-left: auto; display: flex; align-items: center; gap: 10px; }

/* Announcement popup (js/account.js). Shown once per announcement version. */
.notice { width: min(440px, calc(100vw - 32px)); padding: clamp(24px, 4vw, 32px); border: 1px solid var(--line); border-radius: var(--r-lg); background: var(--surface); color: var(--ink); box-shadow: 0 24px 60px -24px rgba(20, 25, 32, .35); }
.notice::backdrop { background: rgba(20, 25, 32, .42); }
.notice__title { font-size: 22px; font-weight: 500; letter-spacing: -0.02em; line-height: 1.25; text-wrap: balance; }
.notice__text { margin-top: 10px; font-size: 15.5px; line-height: 1.7; color: var(--ink-2); }
.notice__actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 10px; margin-top: 24px; }
@media (prefers-reduced-motion: no-preference) {
  .notice[open] { animation: notice-in .22s var(--ease); }
  @keyframes notice-in { from { opacity: 0; transform: translateY(8px); } }
}

.nav__toggle {
  display: none; width: 42px; height: 42px; border-radius: var(--r-md); border: 1px solid var(--line-strong);
  background: transparent; align-items: center; justify-content: center; flex-direction: column; gap: 4px; cursor: pointer;
}
.nav__toggle span { width: 16px; height: 1.5px; background: var(--ink); transition: transform var(--dur) var(--ease); }
.nav__toggle[aria-expanded="true"] span:first-child { transform: translateY(3.25px) rotate(45deg); }
.nav__toggle[aria-expanded="true"] span:last-child { transform: translateY(-3.25px) rotate(-45deg); }

.nav__mobile { display: none; }
.nav__mobile[hidden] { display: none; }

@media (max-width: 1040px) {
  .nav__links { display: none; }
}
@media (max-width: 720px) {
  /* the language switch stays in the header at every width: a visitor who cannot read the page must not have to open a menu to find it */
  .nav__actions .btn--ghost:not([data-lang-switch]) { display: none; }
  .nav__toggle { display: inline-flex; }
  .nav__mobile:not([hidden]) {
    display: grid; gap: 2px; padding: 8px var(--gutter) 16px; border-top: 1px solid var(--line);
    background: var(--bg);
  }
  .nav__mobile a { padding: 12px 10px; border-radius: var(--r-sm); font-size: 17px; }
  .nav__mobile a:hover { background: var(--bg-2); }
}

/* --------------------------------------------------------------------------
   Hero
   -------------------------------------------------------------------------- */
.hero { padding: clamp(40px, 7vw, 96px) 0 0; overflow: clip; }
.hero__grid {
  display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: clamp(32px, 5vw, 72px); align-items: center;
}
.hero__title {
  font-size: clamp(31px, 4vw, 56px);
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1.16;
  text-wrap: balance;
  animation: rise .5s var(--ease) both;
}
.hero__lead {
  margin-top: clamp(20px, 2.4vw, 28px);
  font-size: clamp(16px, 1.4vw, 19px);
  color: var(--ink-2);
  max-width: 34em;
  animation: rise .5s var(--ease) .08s both;
}
.hero__cta { margin-top: clamp(24px, 3vw, 36px); display: flex; flex-wrap: wrap; gap: 10px; align-items: center; animation: rise .5s var(--ease) .16s both; }
@media (max-width: 420px) { .hero__cta .btn--lg { padding: 0 20px; height: 48px; font-size: 15px; } }
@keyframes rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }

.facts {
  margin-top: clamp(56px, 8vw, 112px);
  display: grid; grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line); border-bottom: 1px solid var(--line);
}
.fact { padding: 24px 24px 24px 0; display: grid; gap: 4px; border-left: 1px solid var(--line); padding-left: 24px; }
.fact:first-child { border-left: 0; padding-left: 0; }
.fact strong { font-weight: 500; font-size: 16px; }
.fact span { font-size: 14px; color: var(--ink-3); }

@media (max-width: 960px) {
  .hero__grid { grid-template-columns: 1fr; }
  .hero__visual { max-width: 640px; }
  .facts { grid-template-columns: repeat(2, 1fr); }
  .fact { padding: 20px; }
  .fact:nth-child(odd) { border-left: 0; padding-left: 0; }
  .fact:nth-child(n+3) { border-top: 1px solid var(--line); }
}
@media (max-width: 520px) {
  .telemetry { font-size: 12px; gap: 8px; padding: 8px 12px; }
  .telemetry > :nth-child(n+7) { display: none; }
  .facts { grid-template-columns: 1fr; }
  .fact { border-left: 0; padding-left: 0; border-top: 1px solid var(--line); }
  .fact:first-child { border-top: 0; }
}

/* --------------------------------------------------------------------------
   Sections
   -------------------------------------------------------------------------- */
.section { padding: clamp(72px, 10vw, 140px) 0; }
.section__head { max-width: 860px; }
.section__head h2 { font-size: clamp(30px, 3.6vw, 48px); font-weight: 500; letter-spacing: -0.03em; line-height: 1.12; text-wrap: balance; }
.section__head p { margin-top: 16px; font-size: clamp(16px, 1.3vw, 18px); color: var(--ink-2); max-width: 36em; }
.section__head a { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 3px; }
/* buttons and the contact rows inside a section head are not inline text links */
.section__head a.btn, .section__head a.channel { color: var(--ink); text-decoration: none; }
.section__head a.channel:hover .channel__text { text-decoration: underline; text-underline-offset: 4px; }

/* --------------------------------------------------------------------------
   Pricing / configurator
   -------------------------------------------------------------------------- */
.pricing { padding-top: clamp(64px, 9vw, 120px); }
.config {
  margin-top: clamp(32px, 4vw, 56px);
  display: grid; grid-template-columns: minmax(0, 1fr) 400px; gap: clamp(24px, 3vw, 48px);
  align-items: start;
}
.config__steps { display: grid; gap: clamp(32px, 4vw, 48px); }

.step__title {
  display: flex; align-items: center; gap: 12px;
  font-size: 18px; font-weight: 500; margin-bottom: 16px;
}
.step__n {
  display: inline-grid; place-items: center; width: 26px; height: 26px; border-radius: 50%;
  background: var(--ink); color: #fff; font-size: 13px; font-weight: 500;
}
.step__note { margin-top: 12px; font-size: 14px; color: var(--ink-3); min-height: 1.6em; }

/* plan cards (selectable: cards are justified here) */
.plans { display: grid; gap: 10px; }
.plan {
  position: relative; display: grid; grid-template-columns: 1fr auto; gap: 4px 20px; align-items: center;
  padding: 20px 20px; border-radius: var(--r-lg);
  background: var(--surface); border: 1px solid var(--line);
  cursor: pointer; transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.plan:hover { border-color: var(--line-strong); }
.plan input { position: absolute; inset: 0; opacity: 0; margin: 0; cursor: pointer; }
.plan:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 3px; }
.plan:has(input:checked) { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); }
.plan__head { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.plan__name { font-weight: 500; font-size: 17px; }
.plan__tag { font-size: 12px; padding: 2px 8px; border-radius: var(--r-md); background: var(--accent-soft); color: var(--accent-ink); font-weight: 500; }
.plan__desc { color: var(--ink-2); font-size: 14.5px; grid-column: 1; }
.plan__fit { color: var(--ink-3); font-size: 13.5px; grid-column: 1; }
.plan__price { grid-column: 2; grid-row: 2 / span 2; align-self: end; text-align: right; display: grid; gap: 0; }
.plan__price b { font-size: 24px; font-weight: 500; letter-spacing: -0.02em; }
.plan__price span { font-size: 13px; color: var(--ink-3); }
.plan__meta { grid-column: 2; grid-row: 2 / span 2; align-self: center; text-align: right; display: grid; gap: 2px; font-size: 13px; font-weight: 500; color: var(--ink-2); white-space: nowrap; }
.plan__meta small { font-size: 12px; font-weight: 400; color: var(--ink-3); }
.plan__check {
  grid-column: 2; grid-row: 1; justify-self: end; width: 20px; height: 20px; border-radius: 50%;
  border: 1.5px solid var(--line-strong); display: grid; place-items: center; background: var(--surface);
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.plan__check::after { content: ""; width: 8px; height: 8px; border-radius: 50%; background: #fff; transform: scale(0); transition: transform var(--dur) var(--ease); }
.plan:has(input:checked) .plan__check { background: var(--accent); border-color: var(--accent); }
.plan:has(input:checked) .plan__check::after { transform: scale(1); }

/* periods — segmented */
.periods {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 6px;
  padding: 6px; border-radius: var(--r-md); background: var(--bg-2); border: 1px solid var(--line);
}
.period {
  position: relative; display: grid; justify-items: center; gap: 2px; padding: 12px 10px; border-radius: var(--r-md);
  cursor: pointer; text-align: center; transition: background-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.period input { position: absolute; inset: 0; opacity: 0; margin: 0; cursor: pointer; }
.period:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 2px; }
.period:has(input:checked) { background: var(--surface); box-shadow: 0 2px 10px rgba(23,28,36,.10); }
.period__name { font-weight: 500; font-size: 15px; }
.period__off { font-size: 12.5px; color: var(--ink-3); }
.period:has(input:checked) .period__off { color: var(--accent-ink); }

/* addons */
.addons { display: grid; gap: 10px; }
.addon {
  display: grid; grid-template-columns: 1fr auto auto; gap: 2px 20px; align-items: center;
  padding: 16px 20px; border-radius: var(--r-lg); background: var(--surface); border: 1px solid var(--line);
  cursor: pointer; transition: border-color var(--dur) var(--ease);
}
.addon:hover { border-color: var(--line-strong); }
.addon:has(input:checked) { border-color: var(--accent); }
.addon__name { font-weight: 500; font-size: 16px; }
.addon__desc { color: var(--ink-3); font-size: 13.5px; grid-column: 1; }
.addon__price { grid-column: 2; grid-row: 1 / span 2; font-weight: 500; font-size: 15px; }
.addon__price span { color: var(--ink-3); font-weight: 400; font-size: 13px; }
.switch { grid-column: 3; grid-row: 1 / span 2; position: relative; width: 44px; height: 26px; }
.switch input { position: absolute; inset: 0; opacity: 0; margin: 0; cursor: pointer; }
.switch i {
  position: absolute; inset: 0; border-radius: 999px; background: var(--line-strong); transition: background-color var(--dur) var(--ease);
}
.switch i::after {
  content: ""; position: absolute; top: 3px; left: 3px; width: 20px; height: 20px; border-radius: 50%; background: #fff;
  box-shadow: 0 1px 3px rgba(0,0,0,.25); transition: transform var(--dur) var(--ease);
}
.switch input:checked + i { background: var(--accent); }
.switch input:checked + i::after { transform: translateX(18px); }
.switch input:focus-visible + i { outline: 2px solid var(--accent); outline-offset: 2px; }

/* included */
.included { padding-top: 28px; border-top: 1px solid var(--line); }
.included h3 { font-size: 16px; font-weight: 500; color: var(--ink-2); }
.included ul { list-style: none; margin: 16px 0 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.included li { display: grid; gap: 4px; }
.included li strong { font-weight: 500; }
.included li span { font-size: 14px; color: var(--ink-3); }
.included__byo { margin-top: 24px; padding-top: 20px; border-top: 1px dashed var(--line); font-size: 14.5px; color: var(--ink-2); }
.included__byo a { margin-left: 8px; color: var(--accent-ink); font-weight: 500; text-decoration: underline; text-underline-offset: 3px; }

/* summary */
.summary {
  position: sticky; top: 88px;
  background: var(--ink); color: var(--rack-text);
  border-radius: var(--r-xl); padding: 28px 28px 24px;
  box-shadow: 0 30px 70px rgba(23,28,36,.25);
}
.summary__top h3 { font-size: 14px; font-weight: 500; color: var(--rack-text-2); letter-spacing: 0; }
.summary__plan { margin-top: 6px; font-size: 19px; font-weight: 500; letter-spacing: -0.01em; }
.summary__total { margin-top: 24px; display: grid; gap: 4px; padding-bottom: 20px; border-bottom: 1px solid var(--rack-line); }
.summary__label { font-size: 13px; color: var(--rack-text-2); }
.summary__amount { display: flex; align-items: baseline; gap: 4px; font-weight: 500; letter-spacing: -0.03em; line-height: 1; }
.summary__amount .cur { font-size: 26px; color: var(--rack-text-2); font-weight: 500; }
.summary__amount .num { font-size: 52px; font-variant-numeric: tabular-nums; }
.summary__permo { font-size: 13.5px; color: var(--rack-text-2); }

.summary__spec { margin-top: 4px; font-size: 13.5px; color: var(--rack-text-2); }

/* three-beat timeline */
.timeline { list-style: none; margin: 20px 0 0; padding: 0; display: grid; }
.timeline__step {
  position: relative; display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 1px 16px; align-items: center;
  padding: 8px 0 8px 24px;
}
.timeline__step::before {
  content: ""; position: absolute; left: 4px; top: 50%; width: 9px; height: 9px; margin-top: -4px; border-radius: 50%;
  background: var(--rack-3); border: 2px solid var(--rack-text-2); box-sizing: border-box;
}
.timeline__step::after {
  content: ""; position: absolute; left: 8px; top: calc(50% + 7px); bottom: -9px; width: 1px; background: var(--rack-line);
}
.timeline__step:last-child::after { display: none; }
.timeline__step.is-mark::before { background: var(--accent); border-color: var(--accent); }
.timeline__when { font-size: 14px; font-weight: 500; color: var(--rack-text); }
.timeline__amt { grid-column: 2; grid-row: 1 / span 2; font-size: 18px; font-weight: 600; letter-spacing: -0.01em; font-variant-numeric: tabular-nums; white-space: nowrap; }
.timeline__sub { grid-column: 1; font-size: 12.5px; color: var(--rack-text-2); }
.timeline__step.is-mark .timeline__when { color: #fff; }

.summary__sum {
  margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--rack-line);
  display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 2px 16px; align-items: baseline;
}
.summary__sum-k { font-size: 14px; color: var(--rack-text-2); }
.summary__sum-v { font-size: 22px; font-weight: 500; letter-spacing: -0.02em; font-variant-numeric: tabular-nums; }
.summary__sum-sub { grid-column: 1 / -1; font-size: 12.5px; color: #7F8A9A; }
.summary__hint { margin-top: 12px; font-size: 13px; color: var(--rack-text-2); }
.summary__cta { margin-top: 24px; display: grid; gap: 8px; }
.summary .btn--ink { background: #fff; color: var(--ink); }
.summary .btn--ink:hover { background: var(--bg-2); }
.summary .btn--ghost { color: var(--rack-text); border-color: var(--rack-line); }
.summary .btn--ghost:hover { border-color: var(--rack-text-2); background: transparent; }
.summary__fine { margin-top: 6px; font-size: 12.5px; color: #7F8A9A; text-align: center; }

.num.is-bumping { animation: bump .36s var(--ease); }
@keyframes bump { 0% { transform: translateY(6px); opacity: .4 } 100% { transform: none; opacity: 1 } }

@media (max-width: 980px) {
  .config { grid-template-columns: 1fr; }
  .summary { position: static; }
  .included ul { grid-template-columns: 1fr; gap: 16px; }
}
@media (max-width: 560px) {
  .plan { grid-template-columns: 1fr; padding: 16px 20px; }
  .plan__price { grid-column: 1; grid-row: auto; text-align: left; margin-top: 6px; }
  .plan__meta { grid-column: 1; grid-row: auto; text-align: left; margin-top: 6px; white-space: normal; }
  .plan__check { position: absolute; right: 18px; top: 18px; grid-column: auto; grid-row: auto; }
  .periods { grid-template-columns: repeat(2, 1fr); border-radius: var(--r-lg); }
  .period { border-radius: var(--r-md); }
  .addon { grid-template-columns: 1fr auto; }
  .addon__price { grid-column: 1; grid-row: auto; }
  .switch { grid-column: 2; grid-row: 1 / span 3; }
  .summary { padding: 24px 20px; border-radius: var(--r-lg); }
  .summary__amount .num { font-size: 44px; }
}

/* --------------------------------------------------------------------------
   Architecture (dark)
   -------------------------------------------------------------------------- */
.arch { background: var(--rack); color: var(--rack-text); }
.section__head--dark p { color: var(--rack-text-2); }
.arch__grid {
  margin-top: clamp(40px, 5vw, 72px);
  display: grid; grid-template-columns: 360px minmax(0, 1fr); gap: clamp(32px, 6vw, 96px);
  align-items: start;
}

.chain { list-style: none; margin: 0; padding: 0; position: sticky; top: 100px; display: grid; }
.chain__node {
  position: relative; display: flex; align-items: center; gap: 16px;
  padding: 16px 16px; border-radius: var(--r-md);
  border: 1px solid transparent;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.chain__node + .chain__node { margin-top: 20px; }
.chain__node + .chain__node::before {
  content: ""; position: absolute; left: 35px; top: -19px; width: 2px; height: 18px;
  background: var(--rack-line);
}
.chain__node + .chain__node::after {
  content: ""; position: absolute; left: 32px; top: -5px; width: 8px; height: 8px; border-radius: 50%;
  background: var(--rack-3); border: 2px solid var(--rack-line);
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.chain__icon {
  flex: 0 0 auto; width: 40px; height: 40px; border-radius: 10px; display: grid; place-items: center;
  background: var(--rack-2); border: 1px solid var(--rack-line);
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}
.chain__icon svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.chain__text { display: grid; gap: 1px; }
.chain__text strong { font-weight: 500; font-size: 15.5px; }
.chain__text span { font-size: 13px; color: var(--rack-text-2); }
.chain__node--pair .chain__icon { border-color: var(--accent); color: #fff; }

.chain__node.is-lit { background: var(--rack-2); border-color: var(--rack-line); }
.chain__node.is-lit .chain__icon { background: var(--accent); border-color: var(--accent); color: #fff; }
.chain__node.is-lit + .chain__node::after, .chain__node.is-lit::after { background: var(--accent); border-color: var(--accent); }

.layers { display: grid; }
.layer {
  padding: 24px 0; border-top: 1px solid var(--rack-line);
  display: grid; grid-template-columns: minmax(0, 1fr); gap: 8px;
  cursor: default; outline-offset: 6px; border-radius: 6px;
  transition: opacity var(--dur) var(--ease);
}
.layer:last-child { border-bottom: 1px solid var(--rack-line); }
.layer h3 { font-size: 20px; font-weight: 500; letter-spacing: -0.01em; }
.layer p { color: var(--rack-text-2); font-size: 15.5px; max-width: 62ch; }
.layers.has-focus .layer:not(.is-lit) { opacity: .5; }
.layer.is-lit h3 { color: #fff; }

@media (max-width: 900px) {
  .arch__grid { grid-template-columns: 1fr; }
  .chain { position: static; grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .chain__node + .chain__node { margin-top: 0; }
  .chain__node + .chain__node::before, .chain__node + .chain__node::after { display: none; }
  .chain__node { background: var(--rack-2); border-color: var(--rack-line); }
}
@media (max-width: 520px) {
  .chain { grid-template-columns: 1fr; }
}

/* --------------------------------------------------------------------------
   Process
   -------------------------------------------------------------------------- */
.steps {
  list-style: none; margin: clamp(36px, 5vw, 64px) 0 0; padding: 0;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px;
}
.steps li { padding-top: 20px; border-top: 1px solid var(--line-strong); display: grid; gap: 10px; align-content: start; }
.steps__n { font-size: 13px; color: var(--ink-3); font-variant-numeric: tabular-nums; }
.steps h3 { font-size: 19px; font-weight: 500; }
.steps p { color: var(--ink-2); font-size: 15px; }
@media (max-width: 900px) { .steps { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 520px) { .steps { grid-template-columns: 1fr; gap: 20px; } }

/* --------------------------------------------------------------------------
   FAQ
   -------------------------------------------------------------------------- */
.faq { background: var(--bg-2); }
.faq__grid { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: clamp(32px, 5vw, 80px); align-items: start; }
.faq__list { display: grid; }
.faq details { border-top: 1px solid var(--line-strong); }
.faq details:last-child { border-bottom: 1px solid var(--line-strong); }
.faq summary {
  list-style: none; cursor: pointer; padding: 20px 44px 20px 0; position: relative;
  font-weight: 500; font-size: 17px; line-height: 1.4;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before, .faq summary::after {
  content: ""; position: absolute; right: 14px; top: 50%; width: 14px; height: 1.5px; background: var(--ink);
  transform: translateY(-50%); transition: transform var(--dur) var(--ease);
}
.faq summary::after { transform: translateY(-50%) rotate(90deg); }
.faq details[open] summary::after { transform: translateY(-50%) rotate(0); }
.faq details p { padding: 0 0 24px; color: var(--ink-2); max-width: 60ch; }
.faq__grid > .section__head { position: sticky; top: 104px; }
.faq .section__head .btn { margin-top: 24px; }
.faq summary { font-size: clamp(17px, 1.4vw, 19px); }
@media (max-width: 880px) {
  .faq__grid { grid-template-columns: 1fr; }
  .faq__grid > .section__head { position: static; }
}

/* --------------------------------------------------------------------------
   Contact
   -------------------------------------------------------------------------- */
.contact__grid { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: clamp(32px, 5vw, 80px); align-items: start; }
.channels { list-style: none; margin: 28px 0 0; padding: 0; border: 1px solid var(--line); border-radius: var(--r-lg); background: var(--surface); overflow: hidden; }
.channels li + li { border-top: 1px solid var(--line); }
.channel { display: grid; grid-template-columns: minmax(0, 6.5em) minmax(0, 1fr); gap: 2px 16px; align-items: baseline; padding: 16px 20px; transition: background-color var(--dur) var(--ease); }
a.channel:hover { background: var(--bg); }
.channel__label { font-size: 14px; color: var(--ink-3); }
.channel__text { font-size: 17px; font-weight: 500; color: var(--ink); overflow-wrap: anywhere; }
a.channel .channel__text { color: var(--accent-ink); }
.channel__note { grid-column: 2; font-size: 14px; color: var(--ink-3); }
.channel__label + .channel__note { font-size: 15px; color: var(--ink-2); }

.inquiry { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-xl); padding: clamp(20px, 3vw, 32px); display: grid; gap: 20px; }
.field { display: grid; gap: 8px; }
.field > span { font-size: 14px; font-weight: 500; color: var(--ink-2); }
.field small { font-size: 12.5px; color: var(--ink-3); }
.field input, .field textarea {
  font: inherit; color: var(--ink); background: var(--bg); border: 1px solid var(--line); border-radius: var(--r-md);
  padding: 12px 16px; width: 100%; resize: vertical; transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}
.field input:focus, .field textarea:focus { outline: none; border-color: var(--accent); background: var(--surface); }
.field textarea { line-height: 1.6; font-size: 14.5px; }
.inquiry__row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.inquiry__actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; }
.inquiry__account { font-size: 14px; color: var(--ink-3); max-width: 46em; }
.inquiry__mine { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 3px; }
.inquiry__status { font-size: 14px; line-height: 1.5; color: var(--accent-ink); flex: 1 1 240px; }
.inquiry__status.is-ok { color: #0B6B4B; }
.inquiry__status.is-error { color: #B42318; }
.inquiry__actions .btn:disabled { opacity: .55; cursor: default; }
.inquiry__alt { display: flex; flex-wrap: wrap; align-items: center; gap: 2px 4px; margin: -6px 0 0; font-size: 13.5px; color: var(--ink-3); }
.inquiry__alt .btn { height: 32px; font-size: 13.5px; text-decoration: underline; text-decoration-color: var(--line-strong); text-underline-offset: 4px; }
/* 蜜罐字段：对人不可见、不可聚焦，只有自动填表的脚本会碰它 */
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }
@media (max-width: 880px) { .contact__grid { grid-template-columns: 1fr; } }
@media (max-width: 560px) { .inquiry__row { grid-template-columns: 1fr; } }

/* --------------------------------------------------------------------------
   Three services: hosting / consignment rental / renting, one column each
   -------------------------------------------------------------------------- */
/* the two cards share one set of rows (subgrid), so every line of one card sits level with the same line of the other */
.services__grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); grid-template-rows: auto repeat(3, auto) auto; column-gap: clamp(16px, 2vw, 24px); margin-top: clamp(28px, 4vw, 48px); }
.service { display: grid; grid-row: span 5; grid-template-rows: subgrid; justify-items: start; padding: clamp(24px, 3.2vw, 44px); border-radius: var(--r-lg); background: var(--surface); border: 1px solid var(--line); }
.service h3 { font-size: clamp(30px, 3.6vw, 46px); font-weight: 500; letter-spacing: -0.03em; line-height: 1.08; }
.service__who { margin-top: 10px; font-size: clamp(16px, 1.3vw, 18px); color: var(--ink-2); }
.service > header { padding-bottom: clamp(20px, 2.4vw, 28px); }
.service > .btn { margin-top: clamp(24px, 2.8vw, 32px); align-self: end; }
.service__facts { width: 100%; margin: 0; display: grid; grid-row: span 3; grid-template-rows: subgrid; }
.service__facts div { display: grid; grid-template-columns: 3.5em minmax(0, 1fr); gap: 4px 20px; align-items: baseline; align-content: start; padding: 16px 0; border-top: 1px solid var(--line); }
.service__facts div:last-child { border-bottom: 1px solid var(--line); }
.service__facts dt { font-size: 14px; color: var(--ink-3); }
.service__facts dd { margin: 0; font-size: 15.5px; color: var(--ink-2); }
/* the rental card sits on the dark "rack" surface, so the two ways in read as two different things */
.service--rent { background: var(--rack); border-color: var(--rack); color: var(--rack-text); }
.service--rent .service__who, .service--rent .service__facts dt { color: var(--rack-text-2); }
.service--rent .service__facts dd { color: var(--rack-text); }
.service--rent .service__facts div { border-color: var(--rack-line); }
.service__places { display: flex; flex-wrap: wrap; gap: 8px; }
.service__places a { display: inline-flex; align-items: baseline; gap: 6px; padding: 4px 12px; border-radius: var(--r-md); border: 1px solid var(--line-strong); font-size: 14.5px; color: var(--ink); transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease); }
.service__places a small { font-family: var(--font-mono); font-size: 12px; color: var(--ink-3); font-variant-numeric: tabular-nums; }
.service__places a:hover { border-color: var(--ink); background: var(--bg); }
.service--rent .service__places a { border-color: var(--rack-line); color: var(--rack-text); }
.service--rent .service__places a small { color: var(--rack-text-2); }
.service--rent .service__places a:hover { border-color: var(--rack-text-2); background: var(--rack-2); }
@media (max-width: 900px) { .services__grid { grid-template-columns: 1fr; } .service + .service { margin-top: 16px; } }

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.footer { background: var(--rack); color: var(--rack-text-2); padding: clamp(48px, 6vw, 80px) 0 28px; }
.footer__grid { display: grid; grid-template-columns: minmax(0, 2fr) repeat(3, minmax(0, 1fr)); gap: 32px; }
.footer__brand { display: grid; gap: 16px; align-content: start; max-width: 36ch; }
.footer__brand p { font-size: 14.5px; }
.footer__legal { font-size: 12.5px; color: #6F7987; }
.footer__col { display: grid; gap: 10px; align-content: start; }
.footer__contact { display: contents; }
.footer__col h4 { color: var(--rack-text); font-size: 14px; font-weight: 500; margin-bottom: 4px; }
.footer__col a { font-size: 14.5px; transition: color var(--dur) var(--ease); }
.footer__col a:hover { color: #fff; }
.footer__bottom {
  margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--rack-line);
  display: flex; flex-wrap: wrap; gap: 12px 28px; justify-content: space-between; font-size: 13px;
}
.footer__bottom a:hover { color: #fff; }
@media (max-width: 880px) { .footer__grid { grid-template-columns: 1fr 1fr; } .footer__brand { grid-column: 1 / -1; } }
@media (max-width: 480px) { .footer__grid { grid-template-columns: 1fr; } }

/* toast */
.toast {
  position: fixed; left: 50%; bottom: 24px; transform: translate(-50%, 20px); opacity: 0;
  background: var(--ink); color: #fff; padding: 12px 20px; border-radius: var(--r-md); font-size: 14px;
  box-shadow: 0 16px 40px rgba(0,0,0,.25); z-index: 90; pointer-events: none;
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.toast.is-on { opacity: 1; transform: translate(-50%, 0); }

/* --------------------------------------------------------------------------
   Hosting configurator additions: model picker + payment schedule
   -------------------------------------------------------------------------- */
.models { margin-top: 10px; padding: 16px 16px 12px; border-radius: var(--r-lg); background: var(--bg-2); border: 1px dashed var(--line-strong); }
.models[hidden] { display: none; }
.models__title { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; font-weight: 500; font-size: 15px; margin-bottom: 10px; }
.models__title span { font-weight: 400; font-size: 13px; color: var(--ink-3); }
.models__list { display: grid; gap: 8px; }
.model {
  position: relative; display: grid; grid-template-columns: minmax(0, 1fr) auto auto; gap: 2px 16px; align-items: center;
  padding: 12px 16px; border-radius: var(--r-md); background: var(--surface); border: 1px solid var(--line);
  cursor: pointer; transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.model:hover { border-color: var(--line-strong); }
.model input { position: absolute; inset: 0; opacity: 0; margin: 0; cursor: pointer; }
.model:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 3px; }
.model:has(input:checked) { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); }
.model__name { font-weight: 500; font-size: 15px; display: flex; flex-wrap: wrap; gap: 2px 8px; align-items: baseline; }
.model__name small { font-weight: 400; font-size: 13px; color: var(--ink-2); }
.model__fit { grid-column: 1; font-size: 13px; color: var(--ink-3); }
.model__price { grid-column: 2; grid-row: 1 / span 2; text-align: right; font-weight: 500; font-size: 16px; display: grid; }
.model__price small { font-weight: 400; font-size: 12px; color: var(--ink-3); }
.model .plan__check { grid-column: 3; grid-row: 1 / span 2; position: static; }
.model:has(input:checked) .plan__check { background: var(--accent); border-color: var(--accent); }
.model:has(input:checked) .plan__check::after { transform: scale(1); }


.included { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
.included__col ul { grid-template-columns: 1fr; gap: 16px; }

@media (max-width: 980px) { .included { grid-template-columns: 1fr; } }
@media (max-width: 560px) {
  .model { grid-template-columns: minmax(0, 1fr) auto; }
  .model__price { grid-column: 1; grid-row: auto; text-align: left; margin-top: 4px; }
  .model .plan__check { grid-column: 2; grid-row: 1 / span 3; }
}

/* --------------------------------------------------------------------------
   Residential nodes: hero chips + 托管点 cards + "what we don't have"
   -------------------------------------------------------------------------- */
.hero__dcs {
  margin-top: 28px; max-width: 560px;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 4px; padding: 4px;
  border-radius: 16px; background: var(--bg-2); border: 1px solid var(--line);
  animation: rise .5s var(--ease) .24s both;
}
.chip {
  display: grid; gap: 2px; justify-items: center; text-align: center;
  padding: 10px 8px 8px; border-radius: 12px; border: 0;
  background: transparent; color: var(--ink); font-size: 15px; font-weight: 500; line-height: 1.2; cursor: pointer;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.chip small { font-size: 12px; font-weight: 400; color: var(--ink-3); font-variant-numeric: tabular-nums; white-space: nowrap; }
.chip:hover { background: var(--surface); }
.chip.is-on { background: var(--ink); color: #fff; box-shadow: 0 6px 18px rgba(23,28,36,.18); }
.chip.is-on small { color: rgba(255,255,255,.7); }
.chip:disabled { opacity: .5; cursor: not-allowed; }
.chip:disabled:hover { background: transparent; }

.dcs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; }
.dc {
  position: relative; display: grid; gap: 4px; align-content: start; padding: 20px 20px 16px; border-radius: var(--r-lg);
  background: var(--surface); border: 1px solid var(--line); cursor: pointer;
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.dc:hover { border-color: var(--line-strong); }
.dc input { position: absolute; inset: 0; opacity: 0; margin: 0; cursor: pointer; }
.dc:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 3px; }
.dc:has(input:checked) { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); }
.dc__city { font-weight: 500; font-size: 19px; letter-spacing: -0.01em; padding-right: 28px; }
.dc__meta { font-size: 13px; color: var(--ink-3); }
.dc .plan__check { position: absolute; right: 16px; top: 18px; }
.dc:has(input:checked) .plan__check { background: var(--accent); border-color: var(--accent); }
.dc:has(input:checked) .plan__check::after { transform: scale(1); }
/* 暂停接单的托管点：看得到，但选不了 */
.dc:has(input:disabled), .opt:has(input:disabled) { opacity: .5; }
.dc:has(input:disabled):hover, .opt:has(input:disabled):hover { border-color: var(--line); }
.dc input:disabled, .opt input:disabled { cursor: not-allowed; }

.layer--no h3 { color: var(--rack-text-2); }
.layer--no p { color: #8B95A5; }

@media (max-width: 980px) { .dcs { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .dcs { grid-template-columns: 1fr; } .hero__dcs { grid-template-columns: repeat(2, 1fr); } }

/* --------------------------------------------------------------------------
   Apple-store style machine configurator
   -------------------------------------------------------------------------- */
.cfg { display: grid; gap: 12px; }
.cfg__row { display: grid; grid-template-columns: 44px minmax(0, 1fr); gap: 12px; align-items: start; }
.cfg__label { font-size: 13px; color: var(--ink-3); padding-top: 12px; }
.opts { display: flex; flex-wrap: wrap; gap: 6px; }
.opt {
  position: relative; display: grid; gap: 1px; padding: 8px 12px; border-radius: 10px;
  background: var(--surface); border: 1px solid var(--line); cursor: pointer; font-size: 14px; line-height: 1.35;
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.opt:hover { border-color: var(--line-strong); }
.opt input { position: absolute; inset: 0; opacity: 0; margin: 0; cursor: pointer; }
.opt:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 2px; }
.opt:has(input:checked) { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); }
.opt__name { font-weight: 500; }
.opt__sub { font-size: 12px; color: var(--ink-3); font-variant-numeric: tabular-nums; }
.opt:has(input:checked) .opt__sub { color: var(--accent-ink); }
.cfg__total { margin-top: 16px; font-size: 13.5px; color: var(--ink-2); }
.cfg__total b { color: var(--ink); font-weight: 600; }
@media (max-width: 560px) { .cfg__row { grid-template-columns: 1fr; gap: 6px; } .cfg__label { padding-top: 0; } }

/* --------------------------------------------------------------------------
   Inquiry: button picker + generated brief
   -------------------------------------------------------------------------- */
.pick { display: grid; gap: 10px; }
.pick__row { display: grid; grid-template-columns: 52px minmax(0, 1fr); gap: 10px; align-items: start; }
.pick__label { font-size: 13px; color: var(--ink-3); padding-top: 8px; }
.opt--sm { padding: 6px 12px; border-radius: 9px; font-size: 13.5px; gap: 0; }
.opt--sm .opt__sub { font-size: 11.5px; }
.brief {
  padding: 16px 16px; border-radius: var(--r-md); background: var(--bg); border: 1px solid var(--line);
  font-size: 14.5px; line-height: 1.7; color: var(--ink-2); display: grid; gap: 1px;
}
.brief b { color: var(--ink); font-weight: 500; }
.brief__line { display: grid; grid-template-columns: 5.5em minmax(0, 1fr); gap: 8px; }
.brief__line span:first-child { color: var(--ink-3); }
@media (max-width: 560px) {
  .pick__row { grid-template-columns: 1fr; gap: 4px; }
  .pick__label { padding-top: 0; }
  .brief__line { grid-template-columns: 1fr; gap: 0; }
}

/* ==========================================================================
   Chart identity (2026-11): a single-ink line chart on cool paper.
   Indigo ink for text and strokes, serif headlines, mono for codes and coordinates.
   The one signature is the route: a thin line ending in a ring, used where something goes from here to there.
   ========================================================================== */
h1, h2, h3, h4, .brand__name { font-family: var(--font-display); font-weight: 500; letter-spacing: -0.01em; }
h3, h4 { letter-spacing: 0; }
.brand__name { font-size: 20px; font-weight: 600; }
.brand__mark { filter: none; --mark-bg: var(--ink); --mark-fg: var(--bg); }
.brand--light .brand__mark { --mark-bg: var(--rack-text); --mark-fg: var(--rack); }

/* navigation: plain links, the current one underlined by a moving rule */
.nav__links { padding: 0; gap: 4px; background: none; border: 0; border-radius: 0; }
.nav__links a { padding: 8px 12px; border-radius: var(--r-sm); font-size: 15px; font-weight: 400; }
.nav__indicator { top: auto; bottom: -1px; height: 2px; border-radius: 0; background: var(--ink); box-shadow: none; transition: left .3s var(--ease), width .3s var(--ease), opacity var(--dur) var(--ease); }
.nav__actions .btn { height: 36px; padding: 0 16px; font-size: 14.5px; }

/* hero: copy on the left, the chart on the right */
.hero { padding: clamp(32px, 5vw, 64px) 0 0; }
.hero__grid { grid-template-columns: minmax(0, 1fr) minmax(0, 480px); gap: clamp(32px, 5vw, 80px); align-items: center; }
.hero__title { font-size: clamp(34px, 4.6vw, 64px); font-weight: 500; letter-spacing: -0.02em; line-height: 1.12; animation: rise .5s var(--ease) both; }
.hero__lead { max-width: 30em; font-size: clamp(16px, 1.35vw, 19px); line-height: 1.7; animation: rise .5s var(--ease) .05s both; }
.hero__cta { gap: 12px; animation: rise .5s var(--ease) .1s both; }
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }

.chart { position: relative; margin: 0; animation: rise .5s var(--ease) .15s both; }
.chart__map { width: 100%; height: auto; overflow: visible; }
.chart__grid line { stroke: var(--ink); stroke-opacity: .09; stroke-width: 1; vector-effect: non-scaling-stroke; }
.chart__grid text, .chart__code, .chart__tag { font-family: var(--font-mono); font-size: 10.5px; fill: var(--ink-3); }
.chart__land circle { fill: var(--ink); fill-opacity: .2; }
.chart__route { fill: none; stroke: var(--ink); stroke-linecap: round; stroke-dasharray: 1; stroke-dashoffset: 1; animation: route-draw .5s var(--ease) forwards; stroke-width: 1.25; stroke-opacity: .34; animation-delay: calc(.45s + var(--i) * .16s); transition: stroke-opacity var(--dur) var(--ease), stroke-width var(--dur) var(--ease); }
@keyframes route-draw { to { stroke-dashoffset: 0; } }
.chart__mark { opacity: 0; animation: chart-in .3s var(--ease) forwards; animation-delay: calc(1.05s + var(--i) * .16s); }
.chart__origin.chart__mark { animation-delay: .2s; }
@keyframes chart-in { to { opacity: 1; } }
.chart__ring { fill: var(--bg); stroke: var(--ink); stroke-width: 1.5; }
.chart__dot { fill: var(--ink); opacity: 0; transition: opacity var(--dur) var(--ease); }
.chart__city { font-family: var(--font-display); font-size: 15px; fill: var(--ink-2); transition: fill var(--dur) var(--ease); }
.chart__node { cursor: pointer; }
.chart__node:hover .chart__route { stroke-opacity: .7; }
.chart__node.is-on .chart__route { stroke-opacity: 1; stroke-width: 2; }
.chart__node.is-on .chart__dot { opacity: 1; }
.chart__node.is-on .chart__city { fill: var(--ink); font-weight: 500; }
.chart__node.is-closed { cursor: not-allowed; }
.chart__node.is-closed .chart__route { stroke-opacity: .16; }
.chart__node.is-closed .chart__ring { stroke-dasharray: 2 2; }
.chart__origin .chart__ring { fill: var(--ink); }
.chart__origin .chart__city { fill: var(--ink); font-weight: 500; }
.chart__origin .chart__tag { font-family: var(--font); font-size: 12.5px; fill: var(--ink-2); }
.chart__note { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 4px 16px; margin-top: 8px; font-size: 13px; color: var(--ink-3); }

/* the legend sits on the open sea, top right of the chart */
.chart__legend { position: absolute; top: 8%; right: 0; width: min(46%, 208px); display: grid; gap: 4px; margin: 0; padding: 0; background: none; border: 0; border-radius: 0; animation: none; }
.leg { display: grid; grid-template-columns: 12px minmax(0, 1fr) auto; align-items: center; gap: 8px; width: 100%; padding: 8px 12px; border: 1px solid transparent; border-radius: var(--r-sm); background: color-mix(in srgb, var(--bg) 86%, transparent); color: var(--ink-2); font-size: 14.5px; line-height: 1.3; text-align: left; cursor: pointer; transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), background-color var(--dur) var(--ease); }
.leg::before { content: ""; width: 8px; height: 8px; border-radius: 50%; border: 1.5px solid currentColor; }
.leg small { font-family: var(--font-mono); font-size: 11px; color: var(--ink-3); }
.leg:hover { border-color: var(--line-strong); color: var(--ink); }
.leg.is-on { border-color: var(--ink); background: var(--surface); color: var(--ink); font-weight: 500; }
.leg.is-on::before { background: var(--ink); }
.leg:disabled { opacity: .5; cursor: not-allowed; }
.leg:active:not(:disabled), .btn:active { transform: scale(.98); }
@media (max-width: 960px) {
  .hero__grid { grid-template-columns: 1fr; }
  .chart { max-width: 520px; }
}
@media (max-width: 560px) {
  .chart__legend { position: static; width: auto; grid-template-columns: repeat(2, minmax(0, 1fr)); margin-top: 12px; }
}

/* facts strip, cards and panels pick up the paper-and-ink look */
.facts { margin-top: clamp(40px, 6vw, 80px); }
.fact { padding-block: 20px; }
.fact strong { font-family: var(--font-display); font-weight: 500; font-size: 17px; }
.section { padding: clamp(64px, 9vw, 128px) 0; }
.section__head h2 { font-size: clamp(30px, 3.8vw, 52px); font-weight: 500; letter-spacing: -0.02em; }
.service h3 { font-weight: 500; }
.service--rent, .service--rent .service__facts dd { color: var(--rack-text); }
.faq summary { font-family: var(--font-display); }
.channel__text { font-family: var(--font-mono); font-size: 15.5px; font-weight: 500; }
.footer h4 { font-family: var(--font); font-weight: 500; }

/* language switch (see js/i18n.js): one of the ghost buttons in the header, so the row of actions reads as one set */
.nav__actions [data-lang-switch] { min-width: 48px; justify-content: center; }
/* on a phone the header keeps three things side by side: language, the call to action, the menu */
@media (max-width: 720px) {
  .nav__row { gap: 12px; }
  .nav__actions { gap: 8px; }
  .nav__actions .btn { padding: 0 12px; }
  .nav__actions [data-lang-switch] { min-width: 44px; padding: 0 10px; }
  .nav__toggle { width: 40px; height: 36px; }
}
/* narrower phones: the same three controls, a little tighter; below 350px the English name gives way to the mark */
@media (max-width: 400px) {
  .nav__row { gap: 8px; }
  .brand { gap: 8px; }
  .brand__name { font-size: 17px; }
  .nav__actions { gap: 6px; }
  .nav__actions .btn { padding: 0 10px; }
}
@media (max-width: 350px) { html[data-lang="en"] .brand__name { display: none; } }

/* English labels are longer than the two-character Chinese ones (html[data-lang] is set by js/i18n.js) */
@media (min-width: 561px) {
  html[data-lang="en"] .cfg__row { grid-template-columns: 64px minmax(0, 1fr); }
  html[data-lang="en"] .pick__row { grid-template-columns: 104px minmax(0, 1fr); }
  html[data-lang="en"] .brief__line { grid-template-columns: 8em minmax(0, 1fr); }
}
/* Latin place names are wider than the Chinese ones: keep them inside the chart on narrow screens */
html[data-lang="en"] .chart__city { font-size: 13.5px; }

/* anything marked hidden stays hidden, whatever display its class sets */
[hidden] { display: none !important; }

/* Compute column: one card per device, same paper-and-ink cards as the rest */
/* two cards to a row; the cards of a row share their five rows (subgrid), so names, specs, numbers and buttons sit level */
.devices { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 440px), 1fr)); column-gap: clamp(16px, 2vw, 24px); row-gap: 0; margin-top: clamp(28px, 4vw, 48px); }
.device { display: grid; grid-row: span 5; grid-template-rows: subgrid; row-gap: 0; justify-items: start; margin-bottom: clamp(16px, 2vw, 24px); padding: clamp(20px, 2.4vw, 32px); border-radius: var(--r-lg); background: var(--surface); border: 1px solid var(--line); transition: border-color var(--dur) var(--ease); }
.device > header { grid-row: 1; padding-bottom: 16px; }
.device > .device__specs { grid-row: 2; align-self: start; }
.device > .device__facts { grid-row: 3; align-self: start; padding: 16px 0; }
.device > .device__note { grid-row: 4; align-self: start; padding-bottom: 16px; }
.device > .btn { grid-row: 5; align-self: end; }
.device.is-on { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); }
.device h3 { font-family: var(--font-display); font-size: clamp(22px, 2.2vw, 28px); font-weight: 500; letter-spacing: -0.01em; line-height: 1.2; }
.device__sum { margin-top: 8px; font-size: 15.5px; color: var(--ink-2); }
.device__specs { width: 100%; margin: 0; padding: 0; list-style: none; font-size: 14.5px; color: var(--ink-2); }
.device__specs li { padding: 8px 0; border-top: 1px solid var(--line); }
.device__specs li:last-child { border-bottom: 1px solid var(--line); }
.device__specs:empty { display: none; }
.device__facts { width: 100%; margin: 0; display: grid; gap: 8px; }
.device__facts div { display: grid; grid-template-columns: 7em minmax(0, 1fr); gap: 16px; align-items: baseline; }
.device__facts dt { font-size: 14px; color: var(--ink-3); }
.device__facts dd { margin: 0; font-size: 15.5px; font-variant-numeric: tabular-nums; color: var(--ink); }
.device__facts dd small { display: block; font-size: 12.5px; color: var(--ink-3); }
.device__note { font-size: 14px; color: var(--ink-3); }
.device__note:empty { display: none; }
.compute__note { max-width: 72ch; margin-top: 24px; font-size: 14px; color: var(--ink-3); }
html[data-lang="en"] .device__facts div { grid-template-columns: 10em minmax(0, 1fr); }
/* a single device gets the full row: description on the left, the numbers and the action on the right */
@media (min-width: 761px) {
  .device:only-child { grid-column: 1 / -1; grid-row: auto; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); grid-template-rows: auto auto 1fr auto; grid-template-areas: "head facts" "specs facts" "specs note" "specs cta"; column-gap: clamp(24px, 5vw, 80px); }
  .device:only-child > header { grid-area: head; }
  .device:only-child > .device__specs { grid-area: specs; align-self: start; }
  .device:only-child > .device__facts { grid-area: facts; align-self: start; padding: 8px 0 16px; }
  .device:only-child > .device__note { grid-area: note; }
  .device:only-child > .btn { grid-area: cta; align-self: end; }
}

/* Compute column: pick a region first. The chips wrap, they never scroll sideways. */
.regions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: clamp(24px, 3vw, 32px); }
.regions:empty { display: none; }
.region { display: inline-flex; align-items: baseline; gap: 8px; min-height: 40px; padding: 8px 16px; border: 1px solid var(--line-strong); border-radius: var(--r-md); background: var(--surface); color: var(--ink-2); font: inherit; font-size: 15px; line-height: 1.4; cursor: pointer; transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease), color var(--dur) var(--ease); }
.region small { font-size: 13px; color: var(--ink-3); transition: color var(--dur) var(--ease); }
.region:hover { border-color: var(--ink); color: var(--ink); }
.region.is-on { border-color: var(--ink); background: var(--ink); color: #fff; font-weight: 500; }
.region.is-on small { color: rgba(255, 255, 255, .72); }
.region:active { transform: scale(.98); }
.regions + .devices { margin-top: 24px; }