/* =================== TOKENS =================== */
:root {
  --bg: #0A0A0F;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-2: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.12);
  --indigo: #4F46E5;
  --indigo-2: #6366F1;
  --green: #10B981;
  --text: #F3F4F6;
  --text-2: #9CA3AF;
  --text-3: #6B7280;
  --radius: 10px;
  --radius-lg: 14px;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --container: 1180px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { background: var(--bg); }
body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;

  /* very faint dot watermark */
  background-image:
    radial-gradient(rgba(255,255,255,0.04) 1px, transparent 1px);
  background-size: 24px 24px;
  background-position: 0 0;
}

/* Chinese pages: layer in CJK-friendly fonts so glyphs render correctly */
html[lang^="zh"] body {
  font-family: 'Inter', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei',
               'Noto Sans SC', system-ui, sans-serif;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }

.mono {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-feature-settings: "ss01";
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-size: 11px;
  color: var(--text-2);
}

.muted { color: var(--text-3); }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 32px;
}
.container-narrow { max-width: 820px; }

/* =================== NAV =================== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 10, 15, 0.72);
  backdrop-filter: saturate(140%) blur(12px);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 14px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}
.brand-logo {
  width: 32px;
  height: 32px;
  object-fit: contain;
  flex: none;
}
.brand-name {
  font-weight: 600;
  font-size: 16px;
  letter-spacing: -0.01em;
}
@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; box-shadow: 0 0 0 0 rgba(16,185,129,0.45); }
  50% { transform: scale(1.15); opacity: 0.7; box-shadow: 0 0 0 6px rgba(16,185,129,0); }
}
.nav-right {
  display: flex;
  align-items: center;
  gap: 20px;
}
.nav-links {
  display: flex;
  gap: 28px;
}
.nav-links a {
  font-size: 14px;
  color: var(--text-2);
  transition: color 160ms var(--ease);
}
.nav-links a:hover { color: var(--text); }

/* Language switcher */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding-left: 16px;
  border-left: 1px solid var(--border);
  font-size: 13px;
}
.lang-switch a {
  color: var(--text-3);
  font-weight: 500;
  padding: 4px 2px;
  transition: color 160ms var(--ease);
  letter-spacing: 0.01em;
}
.lang-switch a:hover { color: var(--text); }
.lang-switch a.lang-active {
  color: var(--text);
}
.lang-switch span { color: var(--text-3); }

@media (max-width: 560px) {
  .nav-links { gap: 18px; }
  .nav-links a { font-size: 13px; }
  .nav-right { gap: 12px; }
  .lang-switch { padding-left: 12px; gap: 6px; font-size: 12px; }
}

/* =================== BUTTONS =================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 20px;
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 15px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 120ms var(--ease), background 160ms var(--ease), box-shadow 160ms var(--ease);
  white-space: nowrap;
}
.btn-primary {
  background: var(--indigo);
  color: white;
  box-shadow: 0 1px 0 rgba(255,255,255,0.08) inset, 0 8px 24px -8px rgba(79, 70, 229, 0.6);
}
.btn-primary:hover { background: #5B53EB; transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0); }
.btn-block { width: 100%; }
.btn-link {
  font-size: 14px;
  color: var(--text-2);
  padding: 12px 4px;
  transition: color 160ms var(--ease);
}
.btn-link:hover { color: var(--text); }

/* =================== HERO =================== */
.hero {
  padding: 96px 0 80px;
  position: relative;
  overflow: hidden;
  isolation: isolate;
}
.hero-bg {
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  overflow: hidden;
}
.hero-bg .orb {
  position: absolute;
  border-radius: 999px;
  filter: blur(90px);
  will-change: transform;
  mix-blend-mode: screen;
}
.hero-bg .orb-1 {
  width: 620px; height: 620px;
  background: radial-gradient(circle, rgba(79,70,229,0.55), transparent 65%);
  top: -8%; left: -6%;
  animation: drift1 22s ease-in-out infinite alternate;
}
.hero-bg .orb-2 {
  width: 520px; height: 520px;
  background: radial-gradient(circle, rgba(99,102,241,0.42), transparent 65%);
  bottom: -12%; right: -4%;
  animation: drift2 28s ease-in-out infinite alternate;
}
.hero-bg .orb-3 {
  width: 380px; height: 380px;
  background: radial-gradient(circle, rgba(16,185,129,0.18), transparent 60%);
  top: 45%; left: 55%;
  animation: drift3 34s ease-in-out infinite alternate;
}
@keyframes drift1 {
  0%   { transform: translate(0,0) scale(1); opacity: 0.65; }
  100% { transform: translate(80px, 40px) scale(1.08); opacity: 0.85; }
}
@keyframes drift2 {
  0%   { transform: translate(0,0) scale(1); opacity: 0.55; }
  100% { transform: translate(-60px,-30px) scale(1.06); opacity: 0.75; }
}
@keyframes drift3 {
  0%   { transform: translate(0,0) scale(1); opacity: 0.4; }
  100% { transform: translate(-40px, 30px) scale(1.1); opacity: 0.7; }
}
.hero-bg .scan {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg,
    transparent 0%,
    transparent 48%,
    rgba(99,102,241,0.06) 50%,
    transparent 52%,
    transparent 100%);
  background-size: 100% 220%;
  animation: scan 14s linear infinite;
  opacity: 0.8;
}
@keyframes scan {
  0%   { background-position: 0 -110%; }
  100% { background-position: 0 110%; }
}
.hero-bg .grid-lines {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.6;
}
/* Vignette over hero for legibility */
.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 70% at 50% 50%, transparent 0%, rgba(10,10,15,0.4) 80%, rgba(10,10,15,0.85) 100%);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 72px;
  align-items: center;
}
@media (max-width: 920px) {
  .hero { padding: 60px 0 48px; }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
}
.hero-text h1 {
  font-size: clamp(40px, 6vw, 68px);
  line-height: 1.04;
  letter-spacing: -0.025em;
  font-weight: 600;
  margin: 0 0 24px;
  text-wrap: balance;
}
.hero-sub {
  font-size: 18px;
  color: var(--text-2);
  max-width: 620px;
  margin: 0 0 32px;
  line-height: 1.55;
  text-wrap: pretty;
}
.hero-ctas {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 28px;
  flex-wrap: wrap;
}
.hero-meta {
  font-size: 11.5px;
  color: var(--text-2);
}

/* Activity panel */
.activity-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 18px 16px;
  width: 100%;
  max-width: 400px;
  justify-self: end;
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 12.5px;
  box-shadow:
    0 1px 0 rgba(255,255,255,0.03) inset,
    0 30px 60px -30px rgba(0,0,0,0.6);
}
@media (max-width: 920px) {
  .activity-panel { justify-self: stretch; max-width: 100%; }
}
.activity-head {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 14px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--border);
}
.activity-led {
  width: 7px; height: 7px;
  border-radius: 999px;
  background: var(--green);
  box-shadow: 0 0 8px rgba(16,185,129,0.6);
  animation: pulse 3s var(--ease) infinite;
}
.activity-title {
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--text-2);
}
.activity-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.row {
  display: grid;
  grid-template-columns: auto auto 1fr auto auto;
  gap: 8px;
  align-items: center;
  padding: 6px 4px;
  border-radius: 6px;
  transition: background 200ms var(--ease);
}
.row-no { color: var(--text-3); font-weight: 500; }
.row-name { color: var(--text); }
.row-dots {
  border-bottom: 1px dotted rgba(255,255,255,0.18);
  height: 1px;
  margin: 0 4px;
}
.row-status { color: var(--text-2); }
.row[data-state="done"] .row-status { color: var(--green); }
.row[data-state="running"] .row-status { color: var(--indigo-2); }
.row[data-state="queued"] .row-status { color: var(--text-3); }
.row-time { color: var(--text-3); font-size: 11px; min-width: 64px; text-align: right; }
.row.flash { background: rgba(16,185,129,0.14); }

/* =================== SECTIONS =================== */
.section {
  padding: 96px 0;
  position: relative;
}
.section-tight { padding: 56px 0 96px; }
@media (max-width: 720px) {
  .section { padding: 72px 0; }
  .section-tight { padding: 40px 0 72px; }
}
.section-head {
  margin-bottom: 48px;
  max-width: 720px;
}
.section-head h2 {
  font-size: clamp(28px, 3.6vw, 36px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 600;
  margin: 12px 0 0;
  text-wrap: balance;
}
.section-sub {
  margin-top: 16px;
  font-size: 17px;
  color: var(--text-2);
  line-height: 1.55;
  max-width: 640px;
}
.eyebrow {
  color: var(--text-3);
  display: inline-block;
}

/* =================== CARDS =================== */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: border-color 200ms var(--ease), background 200ms var(--ease);
}
.card:hover {
  border-color: var(--border-strong);
  background: var(--surface-2);
}
.card h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 0 0 10px;
  letter-spacing: -0.01em;
}
.card p {
  margin: 0;
  color: var(--text-2);
  font-size: 15px;
  line-height: 1.55;
}
.card-soft {
  background: transparent;
  border-color: var(--border);
}
.cards-2x2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.cat-card {
  position: relative;
  padding: 32px 32px 28px;
  overflow: hidden;
  isolation: isolate;
}
.cat-card::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background: radial-gradient(ellipse 100% 70% at 100% 0%, rgba(79,70,229,0.14), transparent 60%);
  opacity: 0;
  transition: opacity 320ms var(--ease);
}
.cat-card:hover::before { opacity: 1; }
.cat-card .cat-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px; height: 28px;
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  font-size: 11px;
  color: var(--text-2);
  margin-bottom: 16px;
  transition: color 200ms var(--ease), border-color 200ms var(--ease), background 200ms var(--ease);
}
.cat-card:hover .cat-no {
  color: white;
  border-color: var(--indigo);
  background: rgba(79,70,229,0.15);
}
.cat-card .cat-arrow {
  position: absolute;
  top: 28px;
  right: 28px;
  color: var(--text-3);
  font-size: 18px;
  transform: translate(-4px, 4px);
  opacity: 0;
  transition: opacity 240ms var(--ease), transform 240ms var(--ease), color 240ms var(--ease);
}
.cat-card:hover .cat-arrow {
  opacity: 1;
  transform: translate(0, 0);
  color: var(--indigo-2);
}
.cards-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
@media (max-width: 820px) {
  .cards-2x2 { grid-template-columns: 1fr; }
  .cards-3 { grid-template-columns: 1fr; }
}

/* =================== USPs =================== */
.usp-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.usp {
  background: var(--bg);
  padding: 36px 28px 32px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: background 240ms var(--ease);
  position: relative;
  overflow: hidden;
  isolation: isolate;
}
.usp::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background: radial-gradient(ellipse 60% 80% at 0% 100%, rgba(79,70,229,0.18), transparent 70%);
  opacity: 0;
  transition: opacity 320ms var(--ease);
}
.usp::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--indigo) 30%, var(--indigo) 70%, transparent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 380ms var(--ease);
}
.usp:hover { background: rgba(255,255,255,0.025); }
.usp:hover::before { opacity: 1; }
.usp:hover::after { transform: scaleX(1); }
.usp-no {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--text-3);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.usp-no::after {
  content: '';
  display: inline-block;
  width: 22px;
  height: 1px;
  background: linear-gradient(90deg, var(--indigo), transparent);
}
.usp:hover .usp-no { color: var(--indigo-2); }
.usp h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 0;
  letter-spacing: -0.005em;
}
.usp p {
  margin: 0;
  color: var(--text-2);
  font-size: 14.5px;
  line-height: 1.55;
}
@media (max-width: 560px) {
  .usp-grid { grid-template-columns: 1fr; }
}

/* =================== OUTCOMES =================== */
.outcomes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
@media (max-width: 920px) {
  .outcomes { grid-template-columns: 1fr; }
}
.outcome {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  transition: border-color 200ms var(--ease), transform 240ms var(--ease);
  position: relative;
  overflow: hidden;
}
.outcome::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(99,102,241,0.6), transparent);
  opacity: 0.6;
}
.outcome:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
}
.outcome-meta { color: var(--text-3); }
.outcome-problem {
  margin: 0;
  color: var(--text);
  font-size: 16px;
  line-height: 1.5;
  flex: 1;
}
.outcome-result {
  border-top: 1px solid var(--border);
  padding-top: 18px;
  position: relative;
}
.outcome-num {
  font-size: 44px;
  font-weight: 700;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  display: flex;
  align-items: baseline;
  gap: 8px;
  background: linear-gradient(180deg, #A5B4FC 0%, #6366F1 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1.05;
}
.outcome-unit {
  font-size: 13px;
  color: var(--text-2);
  font-weight: 500;
  letter-spacing: 0;
}
.outcome-tag {
  margin-top: 8px;
  color: var(--green);
  font-size: 11px;
}

/* =================== FAQ =================== */
.faq {
  display: flex;
  flex-direction: column;
  gap: 0;
  border-top: 1px solid var(--border);
}
.faq details {
  border-bottom: 1px solid var(--border);
}
.faq summary {
  list-style: none;
  cursor: pointer;
  padding: 22px 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  font-size: 17px;
  font-weight: 500;
  color: var(--text);
  transition: color 160ms var(--ease);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary:hover { color: var(--indigo-2); }
.faq .chev {
  width: 14px; height: 14px;
  border-right: 1.5px solid var(--text-3);
  border-bottom: 1.5px solid var(--text-3);
  transform: rotate(45deg);
  transition: transform 200ms var(--ease), border-color 200ms var(--ease);
  flex: none;
  margin-right: 4px;
  margin-top: -4px;
}
.faq details[open] .chev {
  transform: rotate(-135deg);
  margin-top: 4px;
  border-color: var(--indigo-2);
}
.faq p {
  margin: 0;
  padding: 0 8px 22px;
  color: var(--text-2);
  font-size: 15.5px;
  line-height: 1.6;
  max-width: 680px;
}

/* =================== CALCULATOR =================== */
.section-calc { background: var(--bg); }
.calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  align-items: stretch;
}
@media (max-width: 920px) {
  .calc-grid { grid-template-columns: 1fr; }
}
.calc-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  position: relative;
  overflow: hidden;
}
.calc-inputs {
  display: flex;
  flex-direction: column;
  gap: 22px;
}
.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.field-label {
  font-size: 10.5px;
  letter-spacing: 0.1em;
}
.input-wrap {
  display: flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  padding: 0 14px;
  min-height: 48px;
  transition: border-color 160ms var(--ease), background 160ms var(--ease);
}
.input-wrap:focus-within {
  border-color: var(--indigo);
  background: rgba(79,70,229,0.05);
  box-shadow: 0 0 0 3px rgba(79,70,229,0.15);
}
.input-wrap input,
.input-wrap textarea {
  flex: 1;
  background: transparent;
  border: 0;
  color: var(--text);
  font-size: 16px;
  font-family: inherit;
  font-variant-numeric: tabular-nums;
  outline: none;
  padding: 0;
  min-width: 0;
}
.input-wrap textarea {
  padding: 14px 0;
  line-height: 1.5;
  resize: vertical;
  min-height: 120px;
}
.input-wrap input::-webkit-outer-spin-button,
.input-wrap input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.input-wrap input[type=number] { -moz-appearance: textfield; }
.input-prefix, .input-suffix {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 13px;
  color: var(--text-2);
  letter-spacing: 0.04em;
  flex: none;
}
.input-prefix { margin-right: 10px; }
.input-suffix { margin-left: 10px; }
.field-help {
  font-size: 12.5px;
  color: var(--text-3);
}
.adv-toggle {
  align-self: flex-start;
  background: transparent;
  border: 0;
  color: var(--text-2);
  cursor: pointer;
  padding: 6px 0;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: color 160ms var(--ease);
}
.adv-toggle:hover { color: var(--text); }
.adv-plus {
  display: inline-flex;
  width: 16px; height: 16px;
  align-items: center; justify-content: center;
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  font-size: 12px;
  transition: transform 200ms var(--ease);
}
.adv-toggle[aria-expanded="true"] .adv-plus { transform: rotate(45deg); }
.adv-panel { margin-top: -6px; }

/* Result card */
.calc-result {
  display: flex;
  flex-direction: column;
  gap: 16px;
  background: linear-gradient(180deg, rgba(255,255,255,0.045), rgba(255,255,255,0.025));
}
.result-glow {
  position: absolute;
  top: -120px; right: -120px;
  width: 360px; height: 360px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.18), transparent 60%);
  pointer-events: none;
}
.result-label {
  color: var(--text-2);
  font-size: 11px;
  letter-spacing: 0.12em;
  position: relative;
}
.result-number {
  font-size: clamp(44px, 6vw, 56px);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--indigo-2);
  font-variant-numeric: tabular-nums;
  line-height: 1.05;
  position: relative;
}
.result-cap {
  margin: -4px 0 4px;
  color: var(--text-2);
  font-size: 14px;
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  letter-spacing: 0.01em;
}
.hairline {
  height: 1px;
  background: var(--border);
  margin: 6px 0;
}
.result-breakdown {
  position: relative;
}
.bd-row { display: none; }
.bd-list {
  list-style: none;
  padding: 0;
  margin: 0 0 8px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  color: var(--text);
  font-size: 15px;
}
.bd-list li {
  display: flex;
  gap: 10px;
  font-variant-numeric: tabular-nums;
}
.bd-bullet { color: var(--text-3); }
.bd-list::before {
  content: "Equivalent to:";
  display: block;
  color: var(--text-2);
  font-size: 14px;
  margin-bottom: 6px;
  font-family: 'Inter', sans-serif;
  font-weight: 500;
  letter-spacing: 0;
}
html[lang^="zh"] .bd-list::before {
  content: "相当于：";
}
.calc-result .btn { margin-top: auto; }

/* Quick-check (qualifying questions) */
.check-field { gap: 6px; }
.check-intro {
  margin: 0 0 4px;
  font-size: 13px;
  color: var(--text-3);
  line-height: 1.5;
}
.check-list {
  list-style: none;
  padding: 0;
  margin: 4px 0 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.check {
  display: block;
  position: relative;
}
.check > input[type="checkbox"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
  width: 0;
  height: 0;
  top: 0;
  left: 0;
}
.check > label {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.02);
  transition: border-color 160ms var(--ease), background 160ms var(--ease);
  user-select: none;
}
.check > label:hover {
  border-color: var(--border-strong);
  background: rgba(255, 255, 255, 0.04);
}
.check-box {
  width: 16px;
  height: 16px;
  border-radius: 4px;
  border: 1px solid var(--border-strong);
  background: transparent;
  flex: none;
  position: relative;
  transition: background 160ms var(--ease), border-color 160ms var(--ease);
}
.check > input:checked + label .check-box {
  background: var(--indigo);
  border-color: var(--indigo);
}
.check-box::after {
  content: '';
  position: absolute;
  left: 4px;
  top: 1px;
  width: 5px;
  height: 9px;
  border: solid white;
  border-width: 0 1.5px 1.5px 0;
  transform: rotate(45deg) scale(0);
  transition: transform 160ms var(--ease);
}
.check > input:checked + label .check-box::after {
  transform: rotate(45deg) scale(1);
}
.check-text {
  font-size: 14px;
  color: var(--text);
  line-height: 1.4;
}
.check > input:focus-visible + label {
  outline: 2px solid var(--indigo);
  outline-offset: 2px;
}

/* Suitability badge */
.suitability {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px 6px 10px;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: rgba(255, 255, 255, 0.02);
  font-size: 12.5px;
  margin: 4px 0 2px;
  transition: background 200ms var(--ease), border-color 200ms var(--ease);
  max-width: fit-content;
}
.suit-dot {
  width: 7px;
  height: 7px;
  border-radius: 999px;
  flex: none;
}
.suit-text {
  color: var(--text);
  font-weight: 500;
  line-height: 1.4;
}
.suitability[data-level="3"] { background: rgba(16, 185, 129, 0.08); border-color: rgba(16, 185, 129, 0.35); }
.suitability[data-level="3"] .suit-dot { background: var(--green); box-shadow: 0 0 8px rgba(16, 185, 129, 0.5); }
.suitability[data-level="2"] { background: rgba(79, 70, 229, 0.08); border-color: rgba(79, 70, 229, 0.35); }
.suitability[data-level="2"] .suit-dot { background: var(--indigo); box-shadow: 0 0 8px rgba(79, 70, 229, 0.5); }
.suitability[data-level="1"] { background: rgba(245, 158, 11, 0.08); border-color: rgba(245, 158, 11, 0.35); }
.suitability[data-level="1"] .suit-dot { background: #F59E0B; box-shadow: 0 0 8px rgba(245, 158, 11, 0.5); }
.suitability[data-level="0"] { background: rgba(255, 255, 255, 0.02); border-color: var(--border); }
.suitability[data-level="0"] .suit-dot { background: var(--text-3); }
.suitability[data-level="0"] .suit-text { color: var(--text-2); }

/* =================== CONTACT =================== */
.section-contact { padding-top: 16px; padding-bottom: 96px; }
.contact-card {
  position: relative;
  background: #07070C;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 48px;
  overflow: hidden;
  box-shadow: 0 30px 80px -40px rgba(0,0,0,0.8);
}
@media (max-width: 720px) {
  .contact-card { padding: 32px 24px; }
}
.contact-glow {
  position: absolute;
  top: -200px; right: -200px;
  width: 520px; height: 520px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.30), transparent 60%);
  pointer-events: none;
}
.contact-head {
  position: relative;
  margin-bottom: 32px;
}
.contact-head h2 {
  font-size: clamp(28px, 3.6vw, 36px);
  margin: 12px 0 12px;
  letter-spacing: -0.02em;
  font-weight: 600;
}
.contact-form {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
@media (max-width: 560px) {
  .form-row { grid-template-columns: 1fr; }
}
.form-foot {
  text-align: center;
  margin: 8px 0 0;
  color: var(--text-3);
}
.form-error {
  background: rgba(239, 68, 68, 0.08);
  border: 1px solid rgba(239, 68, 68, 0.35);
  color: #FCA5A5;
  border-radius: 8px;
  padding: 12px 14px;
  font-size: 13.5px;
  line-height: 1.5;
  margin: 4px 0;
}
.form-foot a { color: var(--text-2); text-decoration: underline; text-underline-offset: 3px; }
.form-foot a:hover { color: var(--text); }

.contact-success {
  position: relative;
  text-align: center;
  padding: 48px 0 16px;
}
.success-check {
  width: 56px; height: 56px;
  border-radius: 999px;
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.5);
  color: var(--green);
  font-size: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}
.contact-success h3 {
  font-size: 24px;
  margin: 0 0 8px;
  font-weight: 600;
}
.contact-success p { color: var(--text-2); margin: 0; }

/* =================== FOOTER =================== */
.footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  color: var(--text-3);
  font-size: 13.5px;
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
.footer a { color: var(--text-2); }
.footer a:hover { color: var(--text); }

/* =================== ANIMATIONS =================== */
/* hero stagger */
[data-anim^="hero-"] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 600ms var(--ease), transform 600ms var(--ease);
}
[data-anim="hero-h1"]    { transition-delay: 100ms; }
[data-anim="hero-sub"]   { transition-delay: 250ms; }
[data-anim="hero-cta"]   { transition-delay: 400ms; transform: translateY(12px); transition-duration: 500ms; }
[data-anim="hero-meta"]  { transition-delay: 550ms; transform: none; transition-duration: 400ms; }
[data-anim="hero-panel"] { transition-delay: 200ms; transform: none; transition-duration: 800ms; }

.is-loaded [data-anim^="hero-"] {
  opacity: 1;
  transform: translateY(0);
}

/* scroll-in (body sections) */
[data-anim=""], [data-anim]:not([data-anim^="hero-"]) {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 500ms var(--ease), transform 500ms var(--ease);
}
.in-view {
  opacity: 1 !important;
  transform: translateY(0) !important;
}

/* respect reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  [data-anim] { opacity: 1 !important; transform: none !important; }
}

/* =================== MOBILE OPTIMIZATIONS =================== */
/* Tablet-ish */
@media (max-width: 720px) {
  .container { padding: 0 24px; }
  .nav-inner { padding: 12px 24px; }
}

/* Phones */
@media (max-width: 560px) {
  /* Tighter container + section + card padding */
  .container { padding: 0 20px; }
  .nav-inner { padding: 12px 20px; }
  .section { padding: 56px 0; }
  .section-tight { padding: 32px 0 56px; }
  .section-head { margin-bottom: 32px; }
  .section-head h2 { font-size: clamp(22px, 6.5vw, 32px); }
  .section-sub { font-size: 14.5px; margin-top: 12px; }
  .card { padding: 22px; }
  .cat-card { padding: 24px 22px 22px; }
  .cat-card .cat-arrow { top: 24px; right: 22px; }
  .usp { padding: 28px 22px 24px; }
  .calc-card { padding: 24px; }
  .calc-inputs { gap: 18px; }
  .contact-card { padding: 28px 20px; }
  .contact-head { margin-bottom: 24px; }

  /* Hero tightens for narrow viewports */
  .hero { padding: 48px 0 36px; }
  .hero-grid { gap: 32px; }
  .hero-text h1 { font-size: clamp(32px, 9vw, 56px); margin-bottom: 18px; }
  .hero-sub { font-size: 15.5px; margin-bottom: 24px; line-height: 1.55; }
  .hero-meta { font-size: 10.5px; }
  .hero-ctas { gap: 12px; }

  /* Activity panel tightens internally */
  .activity-panel { padding: 14px 14px 12px; font-size: 12px; }
  .activity-head { padding-bottom: 12px; margin-bottom: 10px; }
  .activity-title { font-size: 9.5px; letter-spacing: 0.1em; }
  .row { gap: 6px; padding: 5px 4px; }
  .row-time { min-width: 56px; font-size: 10.5px; }

  /* Calculator: bigger touch targets, smaller hero number floor */
  .field-label { font-size: 10px; }
  .input-wrap { min-height: 46px; padding: 0 12px; }
  .input-wrap input, .input-wrap textarea { font-size: 16px; } /* keep ≥16px to prevent iOS zoom */
  .result-number { font-size: clamp(36px, 11vw, 52px); }
  .result-cap { font-size: 13px; }
  .suitability { font-size: 12px; padding: 6px 10px 6px 9px; }

  /* Outcomes: smaller hero number on cards */
  .outcome { padding: 22px; gap: 14px; }
  .outcome-num { font-size: 36px; }
  .outcome-unit { font-size: 12px; }
  .outcome-result { padding-top: 14px; }

  /* FAQ */
  .faq summary { padding: 18px 6px; font-size: 15.5px; }
  .faq p { padding: 0 6px 18px; font-size: 14.5px; }

  /* Larger tap targets on the language switcher */
  .lang-switch a { padding: 8px 4px; }

  /* Contact form */
  .form-row { grid-template-columns: 1fr; }
  .input-wrap textarea { min-height: 110px; }
  .form-foot { font-size: 11px; }
  .success-check { width: 48px; height: 48px; font-size: 24px; }
}

/* Very narrow phones (iPhone SE-class and below ~412px) */
@media (max-width: 460px) {
  .container { padding: 0 16px; }
  .nav-inner { padding: 10px 16px; gap: 16px; }
  /* Drop the 3 anchor links to free up nav width; brand + lang switcher remain */
  .nav-links { display: none; }
  /* Stack hero CTAs full-width */
  .hero-ctas { flex-direction: column; align-items: stretch; }
  .hero-ctas .btn-primary { width: 100%; justify-content: center; }
  .hero-ctas .btn-link { text-align: center; padding-left: 0; }
  .hero-text h1 { font-size: clamp(30px, 10vw, 44px); }
  /* Lang switcher loses its left border on very narrow widths */
  .lang-switch { padding-left: 0; border-left: 0; }
  /* Brand mark shrinks */
  .brand-logo { width: 28px; height: 28px; }
  .brand-name { font-size: 15px; }
  /* Mono labels shrink so the meta-bar fits */
  .activity-title { font-size: 9px; }
}

/* Improve form input behaviour on mobile (prevent iOS zoom-on-focus) */
@media (max-width: 720px) {
  .input-wrap input,
  .input-wrap textarea,
  input[type="number"],
  input[type="text"],
  input[type="email"],
  textarea {
    font-size: 16px !important;
  }
}

/* =================== MOBILE SCROLL PERF =================== */
/* Stop the rubber-band / pull-to-refresh bounce that can read as page "jumping" */
html, body {
  overscroll-behavior-y: none;
}

/* Cleaner tap UX on iOS / Android */
* {
  -webkit-tap-highlight-color: transparent;
}

/* The hero orbs + scan line + 90px GPU blur thrash mobile compositors and
   cause visible jitter when scroll momentum settles. Kill the perpetual
   animations on phones/tablets and bake the glow as a static gradient.   */
@media (max-width: 920px) {
  .hero-bg .orb {
    animation: none !important;
    will-change: auto;
    /* Smaller blur radius is much cheaper to repaint */
    filter: blur(60px);
    /* Solid opacity so they look intentional, not faded mid-animation */
    opacity: 0.6;
  }
  .hero-bg .scan {
    display: none;
  }
  /* Less aggressive backdrop blur on the sticky nav so iOS Safari doesn't
     repaint a heavy filter every scroll frame */
  .nav {
    -webkit-backdrop-filter: saturate(120%) blur(8px);
    backdrop-filter: saturate(120%) blur(8px);
  }
  /* Shorter, smaller scroll-in entrance so any animation that DOES kick in
     after momentum stops is barely perceptible */
  [data-anim=""], [data-anim]:not([data-anim^="hero-"]) {
    transform: translateY(12px);
    transition-duration: 400ms;
  }
}

/* Reduce-motion users get zero hero animation regardless of device */
@media (prefers-reduced-motion: reduce) {
  .hero-bg .orb,
  .hero-bg .scan {
    animation: none !important;
  }
}