:root {
  color-scheme: light;
  --ink: #171717;
  --paper: #f5f1e8;
  --surface: #fffdf7;
  --muted: #66635d;
  --line: #d7d0c2;
  --red: #ee493b;
  --blue: #2068ed;
  --green: #168660;
  --yellow: #f1c94c;
  --night: #101114;
  --content-max: 1180px;
  --header-height: 68px;
  --shadow: 0 22px 60px rgba(31, 28, 21, 0.14);
  --display: 'Aptos Display', 'Segoe UI Variable Display', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --body: 'Aptos', 'Segoe UI Variable Text', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 16px);
}
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body);
  font-size: 16px;
  line-height: 1.55;
  text-rendering: optimizeLegibility;
}
a {
  color: inherit;
}
img {
  display: block;
  max-width: 100%;
  height: auto;
}
.content-wrap {
  width: min(100%, var(--content-max));
  margin-inline: auto;
  padding-inline: clamp(20px, 4vw, 34px);
}
.skip-link {
  position: absolute;
  z-index: 100;
  top: -48px;
  left: 16px;
  padding: 10px 14px;
  background: var(--ink);
  color: #fff;
  border-radius: 6px;
  font-weight: 800;
  text-decoration: none;
}
.skip-link:focus {
  top: 12px;
}
:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 4px;
}

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  border-bottom: 1px solid rgba(23, 23, 23, 0.12);
  background: rgba(245, 241, 232, 0.9);
  backdrop-filter: blur(18px);
}
.header-inner {
  min-height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
}
.site-header::after {
  position: absolute;
  right: 0;
  bottom: -1px;
  left: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--red), var(--blue), var(--green));
  content: '';
  opacity: 0.8;
}
.brand,
.header-actions,
.nav-links {
  display: flex;
  align-items: center;
}
.brand {
  gap: 10px;
  font-family: var(--display);
  font-size: 18px;
  font-weight: 950;
  text-decoration: none;
}
.brand img {
  width: 31px;
  height: 31px;
  border-radius: 8px;
  box-shadow: 0 6px 16px rgba(238, 73, 59, 0.22);
}
.brand-cn {
  margin-left: -4px;
  color: var(--muted);
  font-family: var(--body);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.04em;
}
.footer-brand .brand-cn {
  color: rgba(255, 255, 255, 0.58);
}
.nav-links {
  gap: 3px;
  margin-left: auto;
  font-size: 13px;
  font-weight: 800;
}
.nav-links a,
.header-cta {
  min-height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 11px;
  border-radius: 5px;
  text-decoration: none;
  transition:
    background-color 0.2s,
    transform 0.2s;
}
.nav-links a:hover {
  background: rgba(23, 23, 23, 0.07);
  transform: translateY(-1px);
}
.header-actions {
  gap: 10px;
}
.lang-switch {
  display: inline-flex;
  gap: 2px;
  padding: 3px;
  border: 1px solid rgba(23, 23, 23, 0.14);
  border-radius: 999px;
  background: rgba(23, 23, 23, 0.04);
}
.lang-btn {
  min-width: 38px;
  min-height: 29px;
  padding: 0 8px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--ink);
  font: 800 11px var(--body);
  cursor: pointer;
}
.lang-btn[aria-pressed='true'] {
  background: var(--ink);
  color: #fff;
}
.header-cta {
  background: var(--ink);
  color: #fff;
  font-size: 13px;
  font-weight: 900;
}
.header-cta:hover {
  background: #353535;
  transform: translateY(-1px);
}

.hero {
  position: relative;
  isolation: isolate;
  min-height: 650px;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: var(--night);
  color: #fff;
}
.hero-image {
  position: absolute;
  z-index: -3;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  opacity: 0.58;
}
.hero-shade {
  position: absolute;
  z-index: -2;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(11, 12, 14, 0.95) 0%, rgba(11, 12, 14, 0.74) 48%, rgba(11, 12, 14, 0.26) 100%),
    linear-gradient(0deg, rgba(11, 12, 14, 0.8), transparent 60%);
}
.hero::after {
  position: absolute;
  z-index: -1;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(255, 255, 255, 0.08) 1px, transparent 1px) 0 0 / 88px 88px,
    linear-gradient(0deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px) 0 0 / 88px 88px;
  content: '';
  mask-image: linear-gradient(90deg, black, transparent 82%);
  opacity: 0.38;
}
.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(260px, 0.55fr);
  gap: clamp(28px, 7vw, 96px);
  align-items: center;
  padding-block: 82px;
}
.hero-content {
  max-width: 680px;
}
.eyebrow {
  margin: 0 0 13px;
  color: var(--yellow);
  font-size: 11px;
  font-weight: 950;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.eyebrow-dark {
  color: var(--blue);
}
.hero h1 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(62px, 10vw, 118px);
  font-weight: 950;
  letter-spacing: 0;
  line-height: 0.85;
}
.hero-title-copy {
  margin: 20px 0 0;
  font-family: var(--display);
  font-size: clamp(26px, 4vw, 42px);
  font-weight: 900;
  line-height: 1.08;
  text-wrap: balance;
}
.hero-copy {
  max-width: 52ch;
  margin: 17px 0 0;
  color: rgba(255, 255, 255, 0.8);
  font-size: clamp(17px, 2vw, 20px);
  line-height: 1.55;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 27px;
}
.button {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 19px;
  border: 1px solid transparent;
  border-radius: 5px;
  font-weight: 900;
  text-decoration: none;
  transition:
    transform 0.2s,
    background-color 0.2s,
    border-color 0.2s,
    box-shadow 0.2s;
}
.button:hover {
  transform: translateY(-2px);
}
.button-light {
  background: #fff;
  color: var(--ink);
  box-shadow: 0 12px 28px rgba(255, 255, 255, 0.1);
}
.button-light:hover {
  background: #f4eee3;
}
.button-quiet {
  border-color: rgba(255, 255, 255, 0.3);
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
}
.button-quiet:hover {
  border-color: rgba(255, 255, 255, 0.62);
  background: rgba(255, 255, 255, 0.15);
}
.button-dark {
  background: var(--ink);
  color: #fff;
}
.button-dark:hover {
  background: #3a3936;
}
.button-wide {
  width: 100%;
}
.hero-proof {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
}
.hero-proof li {
  display: grid;
  gap: 2px;
  padding-left: 12px;
  border-left: 2px solid rgba(255, 255, 255, 0.26);
}
.hero-proof strong {
  font-size: 13px;
}
.hero-proof span {
  color: rgba(255, 255, 255, 0.55);
  font-size: 11px;
}
.hero-note {
  max-width: 290px;
  align-self: end;
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 15px;
  padding: 20px 0 0;
  border-top: 1px solid rgba(255, 255, 255, 0.34);
}
.hero-note-mark {
  color: var(--yellow);
  font: 800 13px var(--display);
}
.hero-note-label {
  margin: 0;
  color: rgba(255, 255, 255, 0.54);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.hero-note-title {
  margin: 9px 0 0;
  font-family: var(--display);
  font-size: 20px;
  font-weight: 900;
  line-height: 1.2;
}
.hero-note-copy {
  margin: 11px 0 0;
  color: rgba(255, 255, 255, 0.62);
  font-size: 13px;
  line-height: 1.6;
}

.signal-band {
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}
.signal-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}
.signal-item {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 13px;
  padding: 24px 22px;
  border-right: 1px solid var(--line);
}
.signal-item:first-child {
  padding-left: 0;
}
.signal-item:last-child {
  border-right: 0;
}
.signal-index,
.feature-number,
.process-no {
  color: var(--red);
  font: 900 12px var(--display);
  letter-spacing: 0.08em;
}
.signal-item strong {
  display: block;
  font-family: var(--display);
  font-size: 18px;
  line-height: 1.1;
}
.signal-item p {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.use-modes-section {
  padding-block: clamp(60px, 8vw, 98px);
  background: var(--paper);
}
.use-modes-heading {
  max-width: 700px;
}
.use-modes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin-top: 34px;
}
.use-mode-card {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 18px;
  min-height: 170px;
  padding: 22px;
  border-top: 4px solid var(--blue);
  background: var(--surface);
  box-shadow: 0 12px 28px rgba(23, 23, 23, 0.06);
}
.use-mode-touch {
  border-top-color: var(--green);
}
.use-mode-key {
  color: var(--blue);
  font: 900 34px/1 var(--display);
}
.use-mode-touch .use-mode-key {
  color: var(--green);
}
.use-mode-card h3 {
  margin: 1px 0 0;
  font-family: var(--display);
  font-size: 21px;
  font-weight: 950;
  line-height: 1.15;
}
.use-mode-card p {
  margin: 11px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}
.use-modes-note {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.ai-feature-section {
  padding-block: clamp(70px, 9vw, 112px);
  background: var(--night);
  color: #fff;
}
.ai-feature-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(360px, 1.05fr);
  gap: clamp(34px, 8vw, 110px);
  align-items: center;
}
.ai-feature-copy h2 {
  max-width: 620px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(36px, 5vw, 62px);
  font-weight: 950;
  line-height: 1.02;
  text-wrap: balance;
}
.ai-feature-lead {
  max-width: 62ch;
  margin: 17px 0 0;
  color: rgba(255, 255, 255, 0.72);
  font-size: 16px;
  line-height: 1.7;
}
.ai-feature-copy .button {
  margin-top: 25px;
}
.ai-feature-points {
  display: grid;
  gap: 16px;
  margin: 32px 0 0;
  padding: 0;
  list-style: none;
}
.ai-feature-points li {
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 12px;
  padding-top: 14px;
  border-top: 1px solid rgba(255, 255, 255, 0.17);
}
.ai-feature-points li > span {
  color: var(--yellow);
  font: 900 12px var(--display);
}
.ai-feature-points strong {
  font-family: var(--display);
  font-size: 17px;
}
.ai-feature-points p {
  margin: 4px 0 0;
  color: rgba(255, 255, 255, 0.58);
  font-size: 13px;
  line-height: 1.55;
}
.ai-demo-panel {
  padding: 15px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: #17191e;
  box-shadow: 0 24px 70px rgba(0, 0, 0, 0.28);
}
.ai-demo-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 3px 4px 14px;
  color: rgba(255, 255, 255, 0.86);
  font-size: 13px;
}
.ai-demo-bar span {
  color: var(--yellow);
  font-size: 10px;
  font-weight: 900;
  letter-spacing: 0.14em;
}
.ai-demo-stage {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 30px minmax(0, 1fr);
  gap: 11px;
  align-items: center;
  min-height: 240px;
  padding: 22px;
  background: #0e1014;
}
.ai-demo-selection,
.ai-demo-result {
  min-height: 178px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 10px;
  padding: 17px;
}
.ai-demo-selection {
  position: relative;
  border: 1px dashed var(--blue);
  background: rgba(32, 104, 237, 0.1);
  color: rgba(255, 255, 255, 0.72);
  font-size: 12px;
}
.ai-demo-selection::before,
.ai-demo-selection::after {
  position: absolute;
  width: 13px;
  height: 13px;
  border-color: var(--yellow);
  content: '';
}
.ai-demo-selection::before {
  top: -1px;
  left: -1px;
  border-top: 2px solid;
  border-left: 2px solid;
}
.ai-demo-selection::after {
  right: -1px;
  bottom: -1px;
  border-right: 2px solid;
  border-bottom: 2px solid;
}
.ai-demo-selection i {
  display: block;
  width: 76%;
  height: 7px;
  background: rgba(255, 255, 255, 0.18);
}
.ai-demo-selection i:nth-of-type(2) {
  width: 58%;
}
.ai-demo-selection i:nth-of-type(3) {
  width: 68%;
}
.ai-demo-result {
  border-left: 3px solid var(--green);
  background: rgba(22, 134, 96, 0.12);
}
.ai-demo-result > span {
  color: rgba(255, 255, 255, 0.5);
  font-size: 10px;
  font-weight: 900;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.ai-demo-result strong {
  padding: 8px 9px;
  background: rgba(255, 255, 255, 0.08);
  font-size: 12px;
}
.ai-demo-arrow {
  color: var(--yellow);
  font-size: 24px;
  text-align: center;
}
.ai-demo-foot {
  margin: 13px 4px 0;
  color: rgba(255, 255, 255, 0.48);
  font-size: 11px;
}

.math-feature-section {
  padding-block: clamp(70px, 9vw, 112px);
  background: #ece7dc;
}
.math-feature-grid-home {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(360px, 0.82fr);
  gap: clamp(34px, 8vw, 112px);
  align-items: center;
}
.math-feature-copy-home {
  max-width: 680px;
}
.math-feature-copy-home h2 {
  max-width: 620px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(36px, 5vw, 62px);
  font-weight: 950;
  line-height: 1.02;
  text-wrap: balance;
}
.math-feature-copy-home .button {
  margin-top: 25px;
}
.math-feature-points-home {
  display: grid;
  gap: 13px;
  margin-top: 32px;
}
.math-feature-points-home article {
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 12px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}
.math-feature-points-home article > span {
  color: var(--blue);
  font: 900 12px var(--display);
}
.math-feature-points-home article:nth-child(2) > span {
  color: var(--green);
}
.math-feature-points-home article:nth-child(3) > span {
  color: var(--red);
}
.math-feature-points-home strong {
  font-family: var(--display);
  font-size: 17px;
}
.math-feature-points-home p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}
.math-demo-panel {
  padding: 16px;
  border: 1px solid rgba(23, 23, 23, 0.18);
  background: var(--surface);
  box-shadow: var(--shadow);
}
.math-demo-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 2px 3px 13px;
  color: var(--ink);
  font-size: 13px;
}
.math-demo-bar span {
  color: var(--red);
  font-size: 10px;
  font-weight: 950;
  letter-spacing: 0.12em;
}
.math-demo-formula {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 15px;
  padding: 15px 17px;
  border-left: 3px solid var(--blue);
  background: #f0ece3;
}
.math-demo-formula span {
  color: var(--muted);
  font-size: 11px;
  font-weight: 850;
}
.math-demo-formula strong {
  font: 900 21px var(--display);
}
.math-demo-results {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-top: 12px;
}
.math-demo-results > div {
  display: grid;
  gap: 10px;
  padding: 13px;
  border: 1px solid var(--line);
  background: #faf8f2;
}
.math-demo-results strong {
  font-family: var(--display);
  font-size: 13px;
}
.math-axis,
.math-surface {
  display: block;
  position: relative;
  height: 150px;
  overflow: hidden;
  background: #e6edf8;
}
.math-axis::before,
.math-axis::after {
  position: absolute;
  content: '';
  background: var(--blue);
}
.math-axis::before {
  top: 50%;
  right: 8%;
  left: 8%;
  height: 2px;
}
.math-axis::after {
  top: 8%;
  bottom: 8%;
  left: 50%;
  width: 2px;
}
.math-axis {
  background-image:
    linear-gradient(rgba(32, 104, 237, 0.12) 1px, transparent 1px),
    linear-gradient(90deg, rgba(32, 104, 237, 0.12) 1px, transparent 1px);
  background-size: 24px 24px;
}
.math-axis-2d {
  clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
}
.math-axis-2d::marker {
  content: '';
}
.math-surface {
  background:
    linear-gradient(150deg, transparent 45%, rgba(22, 134, 96, 0.5) 46% 48%, transparent 49%),
    linear-gradient(30deg, transparent 47%, rgba(22, 134, 96, 0.38) 48% 50%, transparent 51%), #e3f0ea;
}
.math-surface::before,
.math-surface::after {
  position: absolute;
  inset: 25% 14%;
  border: 2px solid rgba(22, 134, 96, 0.72);
  transform: skewY(-16deg) rotate(-7deg);
  content: '';
}
.math-surface::after {
  inset: 42% 27%;
  border-color: rgba(32, 104, 237, 0.65);
  transform: skewY(16deg) rotate(7deg);
}
.math-demo-foot {
  margin: 13px 3px 0;
  color: var(--muted);
  font-size: 11px;
}

.section {
  padding-block: clamp(70px, 9vw, 112px);
}
.section-heading {
  max-width: 720px;
}
.section-heading h2,
.purchase-intro h2,
.faq-layout h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(34px, 5vw, 58px);
  font-weight: 950;
  line-height: 1.01;
  text-wrap: balance;
}
.section-lead {
  max-width: 58ch;
  margin: 15px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.65;
}
.feature-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(270px, 0.65fr);
  gap: 14px;
  margin-top: 38px;
}
.feature-primary {
  display: grid;
  grid-template-columns: 0.76fr 1.24fr;
  gap: 22px;
  min-width: 0;
  padding: 24px;
  border: 1px solid var(--line);
  border-top: 4px solid var(--red);
  background: var(--surface);
}
.feature-primary h3,
.feature-item h3,
.process-grid h3 {
  margin: 9px 0 0;
  font-family: var(--display);
  font-size: 21px;
  font-weight: 950;
  line-height: 1.15;
}
.feature-primary p {
  margin: 13px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.62;
}
.text-link {
  display: inline-flex;
  gap: 8px;
  margin-top: 24px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 900;
  text-decoration: none;
}
.text-link:hover {
  text-decoration: underline;
}
.feature-primary-media {
  min-width: 0;
  margin: 0;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  align-self: center;
  background: var(--night);
}
.feature-primary-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.feature-list {
  display: grid;
  gap: 14px;
}
.feature-item {
  padding: 19px 20px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.feature-item p {
  margin: 9px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.58;
}
.feature-red {
  border-top: 4px solid var(--red);
}
.feature-blue {
  border-top: 4px solid var(--blue);
}
.feature-green {
  border-top: 4px solid var(--green);
}
.feature-blue .feature-number {
  color: var(--blue);
}
.feature-green .feature-number {
  color: var(--green);
}
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin-top: 14px;
}
.gallery-grid figure {
  margin: 0;
  padding: 13px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.gallery-grid img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  object-position: top center;
}
.gallery-grid figcaption {
  padding: 10px 2px 1px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
}

.purchase-section {
  padding-block: clamp(70px, 9vw, 112px);
  background: #e7e1d4;
}
.purchase-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 430px);
  gap: clamp(28px, 9vw, 126px);
  align-items: center;
}
.purchase-intro {
  max-width: 600px;
}
.purchase-rule {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 28px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 900;
}
.rule-line {
  width: 42px;
  height: 2px;
  background: var(--red);
}
.price-card {
  padding: 27px;
  border: 1px solid rgba(23, 23, 23, 0.16);
  background: var(--surface);
  box-shadow: var(--shadow);
}
.price-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}
.plan-tag {
  color: var(--red);
  font-size: 11px;
  font-weight: 950;
  letter-spacing: 0.15em;
}
.price-note {
  color: var(--muted);
  font-size: 12px;
}
.price-card h3 {
  margin: 24px 0 0;
  font-family: var(--display);
  font-size: 30px;
  font-weight: 950;
  line-height: 1.05;
}
.price-copy {
  margin: 11px 0 0;
  color: var(--muted);
  font-size: 14px;
}
.check-list {
  display: grid;
  gap: 10px;
  margin: 24px 0;
  padding: 19px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  list-style: none;
}
.check-list li {
  position: relative;
  padding-left: 21px;
  font-size: 14px;
  font-weight: 750;
}
.check-list li::before {
  position: absolute;
  left: 0;
  color: var(--green);
  content: '✓';
  font-weight: 950;
}
.price-footnote {
  margin: 13px 0 0;
  color: var(--muted);
  font-size: 11px;
  line-height: 1.5;
}

.process-section {
  background: var(--surface);
}
.compact-heading {
  max-width: 560px;
}
.process-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 38px;
}
.process-grid article {
  min-height: 210px;
  padding: 20px;
  border-top: 3px solid var(--ink);
  background: var(--paper);
}
.process-grid h3 {
  font-size: 19px;
}
.process-grid p {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.62;
}
.process-no {
  color: var(--blue);
}
.privacy-strip {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 24px;
  align-items: center;
  margin-top: 14px;
  padding: 16px 20px;
  border: 1px solid var(--line);
  background: #f0ece3;
}
.privacy-strip div {
  display: flex;
  align-items: center;
  gap: 9px;
  white-space: nowrap;
}
.privacy-mark {
  color: var(--green);
  font-size: 24px;
  line-height: 1;
}
.privacy-strip p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}
.privacy-strip a {
  color: var(--blue);
  font-size: 13px;
  font-weight: 900;
  text-decoration: none;
  white-space: nowrap;
}
.privacy-strip a:hover {
  text-decoration: underline;
}

.faq-section {
  padding-block: clamp(70px, 9vw, 112px);
  background: var(--night);
  color: #fff;
}
.faq-layout {
  display: grid;
  grid-template-columns: minmax(240px, 0.72fr) minmax(0, 1fr);
  gap: clamp(30px, 9vw, 130px);
}
.faq-section .eyebrow {
  color: var(--yellow);
}
.faq-section h2 {
  color: #fff;
}
.faq-list {
  border-top: 1px solid rgba(255, 255, 255, 0.22);
}
.faq-list details {
  border-bottom: 1px solid rgba(255, 255, 255, 0.18);
}
.faq-list summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 64px;
  cursor: pointer;
  font-family: var(--display);
  font-size: 17px;
  font-weight: 850;
  list-style: none;
}
.faq-list summary::-webkit-details-marker {
  display: none;
}
.faq-list summary::after {
  color: var(--yellow);
  content: '+';
  font-size: 22px;
  font-weight: 400;
}
.faq-list details[open] summary::after {
  content: '−';
}
.faq-list p {
  max-width: 65ch;
  margin: -2px 34px 20px 0;
  color: rgba(255, 255, 255, 0.66);
  font-size: 14px;
  line-height: 1.7;
}

.site-footer {
  padding-block: 35px;
  background: #0b0c0e;
  color: rgba(255, 255, 255, 0.72);
}
.footer-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 14px 30px;
  align-items: center;
}
.footer-brand {
  color: #fff;
  font-family: var(--display);
  font-weight: 950;
  text-decoration: none;
}
.footer-inner p {
  margin: 6px 0 0;
  color: rgba(255, 255, 255, 0.48);
  font-size: 12px;
}
.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 16px;
  font-size: 12px;
  font-weight: 800;
}
.footer-links a {
  text-decoration: none;
}
.footer-links a:hover {
  color: #fff;
}
.footer-small {
  grid-column: 1 / -1;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.13);
}

@media (max-width: 900px) {
  .nav-links a:nth-child(3) {
    display: none;
  }
  .hero-grid,
  .purchase-grid,
  .ai-feature-grid,
  .math-feature-grid-home {
    grid-template-columns: 1fr;
  }
  .hero {
    min-height: auto;
  }
  .hero-grid {
    padding-block: 72px;
  }
  .hero-note {
    max-width: 430px;
    margin-top: 18px;
  }
  .feature-layout {
    grid-template-columns: 1fr;
  }
  .feature-primary {
    grid-template-columns: 0.8fr 1.2fr;
  }
  .faq-layout {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}
@media (max-width: 640px) {
  :root {
    --header-height: 60px;
  }
  .header-inner {
    gap: 10px;
  }
  .nav-links {
    display: none;
  }
  .header-actions {
    margin-left: auto;
  }
  .header-cta {
    padding-inline: 10px;
    font-size: 12px;
  }
  .hero-grid {
    padding-block: 58px;
  }
  .hero-title-copy {
    font-size: 29px;
  }
  .hero-copy {
    font-size: 16px;
  }
  .hero-proof {
    gap: 12px;
  }
  .hero-proof li {
    flex: 1 1 28%;
    min-width: 82px;
  }
  .signal-grid,
  .process-grid,
  .gallery-grid,
  .use-modes-grid {
    grid-template-columns: 1fr;
  }
  .signal-item,
  .signal-item:first-child {
    padding: 18px 0;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
  .signal-item:last-child {
    border-bottom: 0;
  }
  .use-mode-card {
    min-height: 0;
    padding: 19px;
  }
  .ai-demo-stage {
    grid-template-columns: 1fr;
  }
  .ai-demo-arrow {
    transform: rotate(90deg);
  }
  .math-demo-results {
    grid-template-columns: 1fr;
  }
  .math-demo-formula {
    align-items: flex-start;
    flex-direction: column;
    gap: 7px;
  }
  .section,
  .purchase-section,
  .faq-section {
    padding-block: 62px;
  }
  .feature-primary {
    grid-template-columns: 1fr;
    padding: 19px;
  }
  .feature-primary-media {
    grid-row: 1;
  }
  .gallery-grid {
    gap: 12px;
  }
  .purchase-grid {
    gap: 28px;
  }
  .price-card {
    padding: 22px;
  }
  .privacy-strip {
    grid-template-columns: 1fr;
    gap: 10px;
  }
  .privacy-strip a {
    white-space: normal;
  }
  .footer-inner {
    grid-template-columns: 1fr;
  }
  .footer-links {
    justify-content: flex-start;
  }
  .footer-small {
    grid-column: auto;
  }
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}

/* Help page */
.help-page {
  background: var(--paper);
}
.help-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background: var(--night);
  color: #fff;
}
.help-hero-image {
  position: absolute;
  z-index: -3;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 54%;
  opacity: 0.28;
}
.help-hero-shade {
  position: absolute;
  z-index: -2;
  inset: 0;
  background: linear-gradient(90deg, rgba(11, 12, 14, 0.97), rgba(11, 12, 14, 0.7) 60%, rgba(11, 12, 14, 0.28));
}
.help-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(250px, 0.42fr);
  gap: 70px;
  align-items: center;
  padding-block: 76px;
}
.help-hero h1 {
  display: grid;
  gap: 9px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(42px, 7vw, 76px);
  font-weight: 950;
  line-height: 0.95;
}
.help-hero h1 span:last-child {
  color: var(--yellow);
  font-size: 0.58em;
}
.help-lead {
  max-width: 62ch;
  margin: 20px 0 0;
  color: rgba(255, 255, 255, 0.74);
  font-size: 17px;
  line-height: 1.65;
}
.help-toc {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 28px;
}
.help-toc a {
  padding: 7px 11px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 5px;
  color: rgba(255, 255, 255, 0.76);
  font-size: 12px;
  font-weight: 850;
  text-decoration: none;
}
.help-toc a:hover {
  border-color: rgba(255, 255, 255, 0.58);
  color: #fff;
}
.help-cheat {
  padding: 20px;
  border-top: 3px solid var(--yellow);
  background: rgba(15, 16, 18, 0.76);
}
.help-cheat-label {
  margin: 0 0 14px;
  color: rgba(255, 255, 255, 0.5);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.help-cheat-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 5px;
  min-height: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  font-size: 12px;
}
.help-cheat-row:last-child {
  border-bottom: 0;
}
.help-cheat-row small {
  width: 100%;
  margin: -2px 0 7px;
  color: rgba(255, 255, 255, 0.58);
  font-size: 11px;
}
.help-cheat-row kbd {
  background: #fff;
  color: var(--ink);
}
kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 1.55em;
  padding: 0.1em 0.42em;
  border: 1px solid rgba(23, 23, 23, 0.17);
  border-radius: 4px;
  background: #fff;
  color: var(--ink);
  font-family: var(--body);
  font-size: 0.85em;
  font-weight: 850;
  line-height: 1.15;
  box-shadow: 0 1px 0 rgba(23, 23, 23, 0.1);
}
.help-section {
  padding-block: clamp(64px, 8vw, 100px);
}
.help-section-alt {
  border-block: 1px solid var(--line);
  background: #ece7dc;
}
.help-heading {
  max-width: 760px;
}
.help-heading h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(32px, 5vw, 55px);
  font-weight: 950;
  line-height: 1.03;
  text-wrap: balance;
}
.help-heading .section-lead {
  margin-top: 13px;
}
.help-step-grid,
.help-mode-grid,
.help-tools-grid,
.math-feature-grid,
.math-detail-grid,
.ai-flow,
.ai-mode-grid,
.settings-grid {
  display: grid;
  gap: 13px;
  margin-top: 34px;
}
.help-step-grid {
  grid-template-columns: repeat(3, 1fr);
}
.help-step-grid article {
  min-height: 220px;
  padding: 20px;
  border-top: 3px solid var(--red);
  background: var(--surface);
}
.help-step-grid article:nth-child(2) {
  border-color: var(--blue);
}
.help-step-grid article:nth-child(3) {
  border-color: var(--green);
}
.help-step-grid article > span {
  color: var(--red);
  font: 900 12px var(--display);
}
.help-step-grid article:nth-child(2) > span {
  color: var(--blue);
}
.help-step-grid article:nth-child(3) > span {
  color: var(--green);
}
.help-step-grid h3,
.help-mode-card h3,
.help-tools-grid h3,
.math-feature h3,
.math-detail-grid h3,
.ai-mode-grid h3,
.settings-grid h3 {
  margin: 12px 0 0;
  font-family: var(--display);
  font-size: 20px;
  font-weight: 950;
  line-height: 1.15;
}
.help-step-grid p,
.help-mode-card p,
.help-tools-grid p,
.math-feature p,
.math-detail-grid p,
.ai-flow p,
.ai-mode-grid p,
.settings-grid p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}
.help-mode-grid {
  grid-template-columns: repeat(2, 1fr);
}
.help-mode-card {
  padding: 23px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.mode-screen {
  border-top: 4px solid var(--blue);
}
.mode-board {
  border-top: 4px solid var(--green);
}
.mode-label {
  color: var(--blue);
  font-size: 11px;
  font-weight: 950;
  letter-spacing: 0.16em;
}
.mode-board .mode-label {
  color: var(--green);
}
.help-mode-card ul {
  display: grid;
  gap: 8px;
  margin: 18px 0 0;
  padding: 16px 0 0 19px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}
.help-note,
.help-tip {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  margin-top: 14px;
  padding: 15px 18px;
  border-left: 3px solid var(--yellow);
  background: rgba(241, 201, 76, 0.12);
  color: var(--muted);
  font-size: 13px;
  line-height: 1.65;
}
.help-note strong,
.help-tip strong {
  color: var(--ink);
  white-space: nowrap;
}
.help-tools-grid {
  grid-template-columns: repeat(4, 1fr);
}
.help-tools-grid article {
  min-height: 170px;
  padding: 17px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.help-tools-grid article:first-child {
  grid-column: span 2;
  border-top: 4px solid var(--red);
}
.help-tools-grid article:first-child kbd {
  background: var(--red);
  color: #fff;
}
.help-tools-grid article kbd {
  min-width: 27px;
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}
.help-table-wrap {
  margin-top: 34px;
  overflow-x: auto;
  border: 1px solid var(--line);
  background: var(--surface);
}
.help-table-wrap table {
  width: 100%;
  border-collapse: collapse;
  min-width: 680px;
}
.help-table-wrap th,
.help-table-wrap td {
  padding: 13px 16px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  font-size: 13px;
  vertical-align: top;
}
.help-table-wrap th {
  background: var(--ink);
  color: #fff;
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.help-table-wrap tr:last-child td {
  border-bottom: 0;
}
.help-table-wrap td:nth-child(2) {
  white-space: nowrap;
  font-weight: 800;
}
.help-table-wrap td:nth-child(3) {
  color: var(--muted);
}
.math-feature-grid {
  grid-template-columns: repeat(2, 1fr);
}
.math-feature {
  min-height: 200px;
  padding: 23px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.math-feature:first-child {
  border-top: 4px solid var(--blue);
}
.math-feature:last-child {
  border-top: 4px solid var(--red);
}
.math-feature-key {
  color: var(--blue);
  font: 950 38px var(--display);
}
.math-feature:last-child .math-feature-key {
  color: var(--red);
}
.math-detail-grid {
  grid-template-columns: repeat(3, 1fr);
}
.math-detail-grid article {
  padding: 19px;
  border-top: 2px solid var(--ink);
  background: #f0ece3;
}
.ai-flow {
  grid-template-columns: repeat(3, 1fr);
}
.ai-flow-step {
  padding: 19px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.ai-flow-step > span {
  color: var(--red);
  font: 900 12px var(--display);
}
.ai-flow-step strong {
  display: block;
  margin-top: 11px;
  font-family: var(--display);
  font-size: 18px;
}
.ai-mode-grid {
  grid-template-columns: repeat(3, 1fr);
}
.ai-mode-grid article {
  padding: 18px;
  border-top: 3px solid var(--blue);
  background: var(--surface);
}
.ai-mode-grid article:nth-child(2) {
  border-color: var(--green);
}
.ai-mode-grid article:nth-child(3) {
  border-color: var(--red);
}
.ai-config {
  margin-top: 14px;
  padding: 18px;
  border: 1px solid var(--line);
  background: var(--paper);
}
.ai-config strong {
  font-family: var(--display);
  font-size: 17px;
}
.ai-config p {
  max-width: 80ch;
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}
.ai-setup-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-top: 17px;
}
.ai-setup-grid article {
  min-height: 145px;
  padding: 15px;
  border-top: 3px solid var(--blue);
  background: var(--surface);
}
.ai-setup-grid article:nth-child(2) {
  border-color: var(--green);
}
.ai-setup-grid article:nth-child(3) {
  border-color: var(--red);
}
.ai-setup-grid article:nth-child(4) {
  border-color: var(--yellow);
}
.ai-setup-grid article > span {
  color: var(--muted);
  font: 900 11px var(--display);
}
.ai-setup-grid h3 {
  margin: 9px 0 0;
  font-family: var(--display);
  font-size: 16px;
  line-height: 1.15;
}
.ai-setup-grid p {
  margin: 7px 0 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}
.settings-grid {
  grid-template-columns: repeat(2, 1fr);
}
.settings-grid article {
  padding: 20px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.settings-grid article:nth-child(1) {
  border-top: 3px solid var(--red);
}
.settings-grid article:nth-child(2) {
  border-top: 3px solid var(--blue);
}
.settings-grid article:nth-child(3) {
  border-top: 3px solid var(--green);
}
.settings-grid article:nth-child(4) {
  border-top: 3px solid var(--yellow);
}
.help-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin-top: 34px;
  padding: 22px;
  background: var(--ink);
  color: #fff;
}
.help-cta p {
  max-width: 50ch;
  margin: 0;
  font-family: var(--display);
  font-size: 19px;
  font-weight: 850;
  line-height: 1.35;
}
.help-cta > div {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}
.help-cta .button-quiet {
  min-width: 130px;
}

@media (max-width: 900px) {
  .help-hero-grid {
    grid-template-columns: 1fr;
    gap: 35px;
  }
  .help-cheat {
    max-width: 460px;
  }
  .help-tools-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .help-tools-grid article:first-child {
    grid-column: span 2;
  }
  .ai-setup-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 640px) {
  .help-hero-grid {
    padding-block: 55px;
  }
  .help-hero h1 {
    font-size: 43px;
  }
  .help-lead {
    font-size: 16px;
  }
  .help-step-grid,
  .help-mode-grid,
  .math-feature-grid,
  .math-detail-grid,
  .ai-flow,
  .ai-mode-grid,
  .settings-grid,
  .ai-setup-grid {
    grid-template-columns: 1fr;
  }
  .help-tools-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .help-tools-grid article:first-child {
    grid-column: span 2;
  }
  .help-note,
  .help-tip,
  .help-cta {
    display: grid;
  }
  .help-note strong {
    white-space: normal;
  }
  .help-cta > div {
    display: grid;
  }
  .help-cta .button {
    width: 100%;
  }
}

.policy-main {
  padding-block: clamp(64px, 9vw, 110px);
}
.policy-main h1 {
  max-width: 760px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(38px, 6vw, 68px);
  font-weight: 950;
  line-height: 1;
}
.policy-lead {
  max-width: 70ch;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.7;
}
.policy-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin-top: 42px;
}
.policy-grid article {
  padding: 22px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--blue);
  background: var(--surface);
}
.policy-grid article:nth-child(2n) {
  border-top-color: var(--green);
}
.policy-grid article:nth-child(3n) {
  border-top-color: var(--red);
}
.policy-grid h2 {
  margin: 0;
  font-family: var(--display);
  font-size: 20px;
  line-height: 1.15;
}
.policy-grid p {
  margin: 11px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
}
.policy-updated {
  margin: 25px 0 0;
  color: var(--muted);
  font-size: 12px;
}
@media (max-width: 640px) {
  .policy-grid {
    grid-template-columns: 1fr;
  }
  .policy-main {
    padding-block: 58px;
  }
}