/* ==========================================================================
   Helen LLC — shared stylesheet
   Direction: human-approachable palette + commercial sans (Noto Sans SC)
   Layer 1 direction tokens · Layer 2 derived oklch · Layer 3 craft rules
   ========================================================================== */

:root {
  /* --- direction palette (verbatim) --- */
  --bg:      oklch(98% 0.004 240);
  --surface: oklch(100% 0 0);
  --fg:      oklch(20% 0.02 240);
  --muted:   oklch(50% 0.018 240);
  --border:  oklch(90% 0.006 240);
  --accent:  oklch(56% 0.12 170);

  --font-display: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB",
                  "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  --font-body:    "Noto Sans SC", "PingFang SC", "Hiragino Sans GB",
                  "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;

  /* --- derived (oklch only, contrast-checked) --- */
  --accent-ink:      oklch(46% 0.11 170);   /* white text 6.5:1 */
  --accent-ink-hov:  oklch(52% 0.11 170);   /* white text 5.2:1 */
  --accent-tint:     oklch(96% 0.04 170);   /* panel wash, fg text 16:1 */
  --hover-neutral:   oklch(95% 0.008 240);
  --border-strong:   oklch(62% 0.012 240);  /* 3.6:1 on surface */
  --danger:          oklch(50% 0.15 25);
  --danger-tint:     oklch(96% 0.04 25);
  --success-ink:     oklch(45% 0.11 155);
  --success-tint:    oklch(96% 0.04 155);
  --inverse-fg:      oklch(94% 0.01 240);
  --inverse-muted:   oklch(72% 0.015 240);

  /* --- space / shape --- */
  --s1: 4px;  --s2: 8px;  --s3: 12px; --s4: 16px; --s5: 24px;
  --s6: 32px; --s7: 48px; --s8: 64px; --s9: 96px;
  --wrap: 1120px;
  --gut: clamp(20px, 4vw, 40px);
  --r-card: 16px;
  --r-field: 12px;
  --r-pill: 999px;
  --shadow-sm: 0 1px 2px oklch(20% 0.02 240 / .06), 0 6px 18px oklch(20% 0.02 240 / .05);
  --shadow-md: 0 2px 4px oklch(20% 0.02 240 / .07), 0 18px 40px oklch(20% 0.02 240 / .10);
}

/* ==========================================================================
   Base
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  letter-spacing: 0;
  -webkit-font-smoothing: antialiased;
}

html[data-lang="en"] body { line-height: 1.6; }

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

a { color: inherit; }

button, input, select, textarea { font: inherit; color: inherit; }

::selection { background: var(--accent-tint); color: var(--fg); }

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

.skip-link {
  position: absolute;
  left: var(--s4);
  top: -60px;
  z-index: 60;
  background: var(--surface);
  color: var(--fg);
  border: 1px solid var(--border-strong);
  border-radius: var(--r-pill);
  padding: 10px 18px;
  font-size: 14px;
  transition: top .18s ease;
}
.skip-link:focus { top: var(--s3); }

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ==========================================================================
   Typography
   ========================================================================== */

h1, h2, h3, h4, .display {
  font-family: var(--font-display);
  font-weight: 700;
  margin: 0;
  letter-spacing: 0;
  line-height: 1.25;
}

html[data-lang="en"] h1,
html[data-lang="en"] h2,
html[data-lang="en"] h3 { letter-spacing: -0.015em; line-height: 1.18; }

h1 { font-size: clamp(2.25rem, 1.5rem + 3.2vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 1.35rem + 0.7vw, 2rem); }
h3 { font-size: 1.25rem; }

html[data-lang="en"] h1 { letter-spacing: -0.025em; line-height: 1.08; }

p { margin: 0 0 var(--s4); }
p:last-child { margin-bottom: 0; }

.lede {
  font-size: clamp(1.0625rem, 1rem + 0.3vw, 1.125rem);
  color: var(--fg);
  max-width: 62ch;
}

.muted-text { color: var(--muted); }

.small { font-size: 0.875rem; line-height: 1.6; letter-spacing: 0.01em; }

.caption {
  font-size: 0.75rem;
  line-height: 1.5;
  letter-spacing: 0.01em;
  color: var(--muted);
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 var(--s4);
  font-size: 0.75rem;
  font-weight: 650;
  text-transform: uppercase;
  letter-spacing: 0.08em;            /* ALL CAPS floor 0.06em */
  color: var(--muted);
}

html[data-lang="zh"] .eyebrow { letter-spacing: 0.06em; }

.eyebrow .dot {
  flex: none;
  width: 9px; height: 9px;
  border-radius: 50%;
  background: var(--accent);
}

/* editorial section rule: hairline -> eyebrow -> serif heading */
.sec-head {
  border-top: 1px solid var(--border);
  padding-top: var(--s4);
  margin-bottom: var(--s6);
}
.sec-head h2 { max-width: 26ch; }
.sec-head .sec-note { margin-top: var(--s3); color: var(--muted); max-width: 58ch; }

.num {
  font-variant-numeric: tabular-nums;
}

/* ==========================================================================
   Layout
   ========================================================================== */

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gut);
}

.section { padding-block: clamp(56px, 9vw, 104px); }
.section--tight { padding-block: clamp(40px, 6vw, 72px); }

.grid { display: grid; gap: var(--s5); }
@media (min-width: 860px) {
  .grid--split { grid-template-columns: 7fr 5fr; gap: var(--s7); align-items: start; }
}

/* ==========================================================================
   Header
   ========================================================================== */

.site-head {
  position: sticky;
  top: 0;
  z-index: 40;
  background: color-mix(in oklab, var(--surface) 88%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.head-inner {
  display: flex;
  align-items: center;
  gap: var(--s4);
  min-height: 64px;
}

.brand {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  margin-right: auto;
  line-height: 1.2;
}
.brand-name {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.brand-sub {
  font-size: 0.6875rem;
  letter-spacing: 0.05em;
  color: var(--muted);
  text-transform: uppercase;
}
@media (max-width: 520px) { .brand-sub { display: none; } }

.nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 3vw, 28px);
}
.nav a {
  font-size: 0.9375rem;
  font-weight: 550;
  letter-spacing: 0.02em;
  color: var(--muted);
  text-decoration: none;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: color .16s ease, border-color .16s ease;
}
.nav a:hover { color: var(--fg); border-bottom-color: var(--border-strong); }
.nav a[aria-current="page"] {
  color: var(--fg);
  border-bottom-color: var(--fg);
}

.lang-toggle {
  flex: none;
  min-width: 46px;
  min-height: 40px;
  padding: 0 12px;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--r-pill);
  font-size: 0.8125rem;
  font-weight: 650;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: background .16s ease, border-color .16s ease;
}
.lang-toggle:hover { background: var(--hover-neutral); border-color: var(--fg); }

/* ==========================================================================
   Buttons & links
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 46px;
  padding: 0 24px;
  border-radius: var(--r-pill);
  border: 1px solid transparent;
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background .16s ease, border-color .16s ease, transform .1s ease,
              box-shadow .16s ease;
}
.btn:active { transform: translateY(1px); }

.btn--primary {
  background: var(--accent-ink);
  color: var(--surface);
  box-shadow: var(--shadow-sm);
}
.btn--primary:hover { background: var(--accent-ink-hov); }

.btn--ghost {
  background: transparent;
  color: var(--fg);
  border-color: var(--border-strong);
}
.btn--ghost:hover {
  background: var(--hover-neutral);
  border-color: var(--fg);
}

.btn--quiet {
  background: var(--surface);
  color: var(--fg);
  border-color: var(--border);
}
.btn--quiet:hover { background: var(--hover-neutral); border-color: var(--border-strong); }

.btn--block { width: 100%; }

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: 600;
  font-size: 0.9375rem;
  letter-spacing: 0.02em;
  color: var(--fg);
  text-decoration: none;
  border-bottom: 1px solid var(--border-strong);
  padding-bottom: 2px;
  transition: border-color .16s ease;
}
.text-link:hover { border-bottom-color: var(--fg); }
.text-link svg { transition: transform .16s ease; }
.text-link:hover svg { transform: translateX(3px); }

/* ==========================================================================
   Photos & caption chip
   ========================================================================== */

.photo { margin: 0; position: relative; }

.photo img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  max-height: 520px;
  object-fit: cover;
  object-position: center;
  background: var(--hover-neutral);
  border-radius: var(--r-card);
}

.photo--card img {
  aspect-ratio: 3 / 2;
  max-height: none;
  border-radius: var(--r-card) var(--r-card) 0 0;
}

.photo figcaption {
  position: absolute;
  left: 16px;
  bottom: 16px;
  max-width: calc(100% - 32px);
  padding: 9px 14px;
  background: var(--surface);
  color: var(--fg);
  border-radius: 10px;
  box-shadow: var(--shadow-md);
  font-size: 0.75rem;
  line-height: 1.45;
  letter-spacing: 0.01em;
}
.photo figcaption .credit { color: var(--muted); }

/* ==========================================================================
   Masthead / hero
   ========================================================================== */

.masthead { padding-top: clamp(40px, 7vw, 80px); padding-bottom: clamp(32px, 5vw, 56px); }
.masthead h1 { max-width: 15ch; margin-bottom: var(--s5); }
html[data-lang="en"] .masthead h1 { max-width: 17ch; }
.masthead .lede { margin-bottom: var(--s5); }

.hero-photo { padding-bottom: clamp(8px, 2vw, 20px); }

/* ==========================================================================
   Team section
   ========================================================================== */

.stat-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: var(--s5);
  display: grid;
  gap: var(--s5);
}

.stat {
  border-top: 1px solid var(--border);
  padding-top: var(--s4);
}
.stat:first-child { border-top: 0; padding-top: 0; }

.path-stat {
  display: block;
  padding-bottom: var(--s3);
  border-bottom: 1px solid var(--border);
}
.path-stat .stat-label { margin-top: 2px; }

.stat-num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 1.8rem + 2.6vw, 3.25rem);
  font-weight: 600;
  line-height: 1.05;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}
.stat-num .stat-unit {
  font-size: 0.4em;
  font-weight: 600;
  letter-spacing: 0;
  margin-left: 4px;
  color: var(--muted);
}
html[data-lang="zh"] .stat-num { letter-spacing: 0; line-height: 1.2; }

.stat-label {
  display: block;
  margin-top: 6px;
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.5;
}

.steps {
  list-style: none;
  margin: var(--s5) 0 0;
  padding: 0;
  counter-reset: step;
}
.steps li {
  counter-increment: step;
  display: flex;
  gap: var(--s4);
  padding: var(--s4) 0;
  border-top: 1px solid var(--border);
}
.steps li::before {
  content: counter(step, decimal-leading-zero);
  flex: none;
  font-size: 0.75rem;
  font-weight: 650;
  letter-spacing: 0.06em;
  color: var(--muted);
  padding-top: 5px;
  font-variant-numeric: tabular-nums;
}
.steps li span { line-height: 1.6; }

/* ==========================================================================
   Service path cards
   ========================================================================== */

.paths {
  display: grid;
  gap: var(--s5);
}
@media (min-width: 800px) { .paths { grid-template-columns: 1fr 1fr; gap: var(--s6); } }

.path-card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  overflow: hidden;
  text-decoration: none;
  color: inherit;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}
.path-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}
.path-card:focus-visible { outline-offset: 4px; }

.path-card .photo img { transition: transform .35s ease; }
.path-card:hover .photo img { transform: scale(1.025); }

.path-body {
  display: flex;
  flex-direction: column;
  gap: var(--s3);
  padding: var(--s5);
  flex: 1;
}
.path-tag {
  font-size: 0.6875rem;
  font-weight: 650;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}
.path-title { font-size: 1.375rem; }
.path-sub { font-size: 0.9375rem; color: var(--muted); margin-top: -4px; }
.path-copy { font-size: 0.9375rem; line-height: 1.7; color: var(--fg); }
.path-cta {
  margin-top: auto;
  padding-top: var(--s3);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.9375rem;
  letter-spacing: 0.02em;
  border-bottom: 1px solid var(--border-strong);
  align-self: flex-start;
  padding-bottom: 2px;
}
.path-card:hover .path-cta { border-bottom-color: var(--fg); }
.path-card:hover .path-cta svg { transform: translateX(3px); }
.path-cta svg { transition: transform .16s ease; }

/* ==========================================================================
   Service areas
   ========================================================================== */

.area-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: var(--s5);
  display: grid;
  gap: var(--s5);
}
.area-group + .area-group { border-top: 1px solid var(--border); padding-top: var(--s5); }

.area-name {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
  margin-bottom: var(--s4);
}
.area-name strong {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 600;
}
.area-name .county {
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  color: var(--muted);
  text-transform: uppercase;
}

.chips { display: flex; flex-wrap: wrap; gap: 10px; list-style: none; margin: 0; padding: 0; }
.chip {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 8px 16px;
  background: var(--bg);
  border: 1px solid var(--border-strong);
  border-radius: var(--r-pill);
  font-size: 0.9375rem;
  line-height: 1.4;
}
.chip .alt { font-size: 0.8125rem; color: var(--muted); }

/* ==========================================================================
   Panels / notes
   ========================================================================== */

.note {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: var(--s5);
  font-size: 0.9375rem;
  line-height: 1.7;
}
.note h3 { margin-bottom: var(--s3); font-size: 1.0625rem; }

.note--warn { background: var(--accent-tint); border-color: transparent; }
.note--warn h3 { color: var(--fg); }

.honest-note {
  border-top: 1px solid var(--border);
  padding-top: var(--s4);
  margin-top: var(--s5);
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.65;
  max-width: 62ch;
}

.pay-grid {
  display: grid;
  gap: var(--s5);
}
@media (min-width: 800px) {
  .pay-grid { grid-template-columns: 1fr 1fr; gap: var(--s6); align-items: stretch; }
}

.pay-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: var(--s5);
}
.pay-card h3 { font-size: 1.375rem; margin-bottom: var(--s2); }
.pay-lead { margin: 0 0 var(--s4); color: var(--muted); font-size: 0.9375rem; }
.pay-list { list-style: none; margin: 0; padding: 0; display: grid; gap: var(--s3); }
.pay-list li {
  padding-top: var(--s3);
  border-top: 1px solid var(--border);
  font-size: 0.9375rem;
  line-height: 1.6;
}

/* ==========================================================================
   Forms
   ========================================================================== */

.form-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: clamp(20px, 4vw, 36px);
}

.field-grid {
  display: grid;
  gap: var(--s4);
  grid-template-columns: 1fr;
}
@media (min-width: 700px) {
  .field-grid { grid-template-columns: 1fr 1fr; }
  .field--full { grid-column: 1 / -1; }
}

.field label,
.field .field-label {
  display: block;
  margin-bottom: 6px;
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.req { color: var(--danger); margin-left: 2px; }

.field input[type="text"],
.field input[type="tel"],
.field select,
.field textarea {
  width: 100%;
  min-height: 48px;
  padding: 12px 14px;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--r-field);
  font-size: 1rem;
  line-height: 1.5;
  transition: border-color .16s ease, box-shadow .16s ease;
}
.field textarea { min-height: 110px; resize: vertical; }

.field select {
  appearance: none;
  -webkit-appearance: none;
  padding-right: 42px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8' fill='none'%3E%3Cpath d='M1 1.75 6 6.25 11 1.75' stroke='%235a656d' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 16px center;
}

.field input:hover, .field select:hover, .field textarea:hover { border-color: var(--fg); }
.field input:focus, .field select:focus, .field textarea:focus {
  outline: none;
  border-color: var(--accent-ink);
  box-shadow: 0 0 0 3px var(--accent-tint);
}
.field input:focus-visible, .field select:focus-visible, .field textarea:focus-visible {
  outline: 2px solid var(--accent-ink);
  outline-offset: 1px;
}

.field [aria-invalid="true"] {
  border-color: var(--danger);
  background: var(--danger-tint);
}
.field [aria-invalid="true"]:focus { box-shadow: 0 0 0 3px var(--danger-tint); }

.field-error {
  display: none;
  margin: 6px 0 0;
  font-size: 0.8125rem;
  line-height: 1.5;
  color: var(--danger);
}
.field-error.is-visible { display: block; }

.field-hint { margin: 6px 0 0; font-size: 0.8125rem; color: var(--muted); line-height: 1.5; }

.consent {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.9375rem;
  line-height: 1.6;
}
.consent input[type="checkbox"] {
  flex: none;
  width: 20px;
  height: 20px;
  margin: 3px 0 0;
  accent-color: var(--accent-ink);
  cursor: pointer;
}

.form-foot {
  margin-top: var(--s5);
  padding-top: var(--s5);
  border-top: 1px solid var(--border);
  display: grid;
  gap: var(--s3);
}

/* success recap */
.success-panel {
  background: var(--success-tint);
  border-radius: var(--r-card);
  padding: clamp(20px, 4vw, 32px);
}
.success-panel h3 { font-size: 1.25rem; margin-bottom: var(--s3); }
.success-head {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--success-ink);
}
.success-recap {
  margin: var(--s4) 0;
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 6px var(--s4);
  font-size: 0.9375rem;
  background: var(--surface);
  border-radius: 10px;
  padding: var(--s4);
}
.success-recap dt { color: var(--muted); font-size: 0.875rem; }
.success-recap dd { margin: 0; word-break: break-word; }
.success-note { font-size: 0.875rem; color: var(--muted); line-height: 1.65; margin-bottom: var(--s4); }

/* ==========================================================================
   Solar calculator
   ========================================================================== */

.calc-layout { display: grid; gap: var(--s5); }
@media (min-width: 900px) {
  .calc-layout { grid-template-columns: 1fr 1fr; gap: var(--s6); align-items: start; }
}

.calc-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: clamp(20px, 4vw, 32px);
}

.calc-fields { display: grid; gap: var(--s4); }

.money-input { position: relative; }
.money-input .prefix {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  font-size: 1rem;
  pointer-events: none;
}
.money-input input { padding-left: 30px; font-variant-numeric: tabular-nums; }

.assump {
  margin-top: var(--s5);
  border-top: 1px solid var(--border);
  padding-top: var(--s4);
}
.assump h3 {
  font-size: 0.8125rem;
  font-family: var(--font-body);
  font-weight: 650;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: var(--s3);
}
.assump table { width: 100%; border-collapse: collapse; font-size: 0.9375rem; }
.assump th, .assump td {
  text-align: left;
  padding: 9px 0;
  border-bottom: 1px solid var(--border);
}
.assump tr:last-child th, .assump tr:last-child td { border-bottom: 0; }
.assump th { font-weight: 600; letter-spacing: 0.02em; }
.assump td { text-align: right; color: var(--fg); font-variant-numeric: tabular-nums; }
.assump .assump-note { margin-top: var(--s3); font-size: 0.8125rem; color: var(--muted); line-height: 1.6; }

.calc-result {
  background: var(--accent-tint);
  border-radius: var(--r-card);
  padding: clamp(20px, 4vw, 32px);
  min-height: 240px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.result-empty { color: var(--muted); font-size: 0.9375rem; max-width: 34ch; }

.res-assume {
  font-size: 0.8125rem;
  font-weight: 650;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: var(--s4);
}
html[data-lang="zh"] .res-assume { letter-spacing: 0.04em; }

.res-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--s3);
  padding: var(--s4) 0;
  border-top: 1px solid oklch(46% 0.11 170 / .18);
}
.res-row:first-of-type { border-top: 0; padding-top: 0; }
.res-label { font-size: 0.9375rem; color: var(--fg); }
.res-value {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 1.3rem + 1.8vw, 2.25rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
}

.calc-disclaimer {
  margin-top: var(--s5);
  border-top: 1px solid var(--border);
  padding-top: var(--s4);
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--fg);
  max-width: 68ch;
}
.calc-disclaimer strong { font-weight: 650; }

/* ==========================================================================
   WeChat dialog
   ========================================================================== */

.wechat-dlg {
  width: min(420px, calc(100% - 32px));
  padding: var(--s5);
  background: var(--surface);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  box-shadow: var(--shadow-md);
}
.wechat-dlg::backdrop { background: color-mix(in oklab, var(--fg) 45%, transparent); }
.wechat-dlg h2 { font-size: 1.25rem; margin-bottom: var(--s2); }
.wechat-dlg .dlg-copy { font-size: 0.9375rem; color: var(--muted); margin-bottom: var(--s4); }

.wechat-id {
  display: block;
  background: var(--bg);
  border: 1px solid var(--border-strong);
  border-radius: 10px;
  padding: 14px 16px;
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  word-break: break-all;
  margin-bottom: var(--s4);
  user-select: all;
}

.dlg-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.dlg-actions .btn { flex: 1 1 auto; }

/* ==========================================================================
   Sticky mobile action bar
   ========================================================================== */

.sticky-bar {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: 45;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px calc(8px + env(safe-area-inset-bottom));
  background: color-mix(in oklab, var(--surface) 94%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-top: 1px solid var(--border);
  box-shadow: 0 -6px 24px oklch(20% 0.02 240 / .07);
}

.sticky-action {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  flex: 1 1 0;
  min-height: 52px;
  padding: 6px 4px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 12px;
  color: var(--fg);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background .16s ease, border-color .16s ease;
}
.sticky-action:hover { background: var(--hover-neutral); border-color: var(--border); }
.sticky-action svg { width: 20px; height: 20px; }

.sticky-action--primary {
  flex: 1.35 1 0;
  background: var(--accent-ink);
  color: var(--surface);
  border-radius: var(--r-pill);
}
.sticky-action--primary:hover { background: var(--accent-ink-hov); border-color: transparent; }

@media (min-width: 769px) {
  .sticky-bar { display: none; }
}
@media (max-width: 768px) {
  body { padding-bottom: calc(76px + env(safe-area-inset-bottom)); }
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-foot {
  background: var(--fg);
  color: var(--inverse-fg);
  padding-block: var(--s7) var(--s5);
  margin-top: clamp(32px, 6vw, 64px);
}

.foot-grid {
  display: grid;
  gap: var(--s6);
  grid-template-columns: 1fr;
}
@media (min-width: 760px) {
  .foot-grid { grid-template-columns: 1.4fr 1fr 1fr; gap: var(--s7); }
}

.foot-brand .brand-name { color: var(--inverse-fg); font-size: 1.25rem; }
.foot-brand p { color: var(--inverse-muted); font-size: 0.9375rem; margin-top: var(--s3); max-width: 34ch; }

.foot-col h3 {
  font-family: var(--font-body);
  font-size: 0.75rem;
  font-weight: 650;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--inverse-muted);
  margin-bottom: var(--s3);
}

.foot-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; font-size: 0.9375rem; }
.foot-list a, .foot-link {
  color: var(--inverse-fg);
  text-decoration: none;
  border-bottom: 1px solid oklch(72% 0.015 240 / .5);
  padding-bottom: 1px;
  transition: border-color .16s ease;
}
.foot-list a:hover, .foot-link:hover { border-bottom-color: var(--inverse-fg); }
.foot-list button.foot-link {
  background: none;
  border: 0;
  border-bottom: 1px solid oklch(72% 0.015 240 / .5);
  padding: 0 0 1px;
  cursor: pointer;
  font-size: inherit;
}
.foot-plain { color: var(--inverse-muted); }

.foot-bottom {
  margin-top: var(--s6);
  padding-top: var(--s4);
  border-top: 1px solid oklch(94% 0.01 240 / .16);
  display: flex;
  flex-wrap: wrap;
  gap: var(--s3) var(--s5);
  align-items: baseline;
  justify-content: space-between;
  font-size: 0.75rem;
  line-height: 1.6;
  color: var(--inverse-muted);
}
.foot-bottom a { color: var(--inverse-muted); }
.foot-credits { max-width: 70ch; }
.foot-eho { display: inline-flex; align-items: center; gap: 8px; letter-spacing: 0.02em; }
.foot-eho svg { width: 16px; height: 16px; flex: none; }

/* ==========================================================================
   Utilities
   ========================================================================== */

[hidden] { display: none !important; }

/* bilingual string wrapper: one DOM tree, CSS picks the visible language */
.i18n { display: contents; }
h1.i18n, h2.i18n, h3.i18n, h4.i18n, p.i18n { display: block; }
html[data-lang="zh"] .i18n > [lang="en"],
html[data-lang="en"] .i18n > [lang="zh"] { display: none; }
.i18n > p { margin-bottom: var(--s4); }
.i18n > p:last-child { margin-bottom: 0; }

/* button that reads as a plain text link */
.link-btn {
  background: none;
  border: 0;
  border-bottom: 1px solid var(--border-strong);
  padding: 0 0 2px;
  font: inherit;
  font-weight: 600;
  font-size: 0.9375rem;
  letter-spacing: 0.02em;
  color: var(--fg);
  cursor: pointer;
  transition: border-color .16s ease;
}
.link-btn:hover { border-bottom-color: var(--fg); }

dialog:not([open]) { display: none; }

.stack-sm > * + * { margin-top: var(--s3); }
.stack > * + * { margin-top: var(--s5); }
.section-cta { margin-top: var(--s6); }

[data-od-id] { scroll-margin-top: 96px; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}