:root {
  color-scheme: light;
  --bg: #f6f7f8;
  --surface: #ffffff;
  --paper: #e9eef0;
  --ink: #16191a;
  --muted: #536066;
  --line: #d5dde0;
  --signal: #41616e;
  --signal-pale: #e7eef0;
  --dark: #161b1d;
  --dark-line: #414c50;
  --dark-muted: #b8c1c3;
  --focus: #1f6b85;
  --max: 1160px;
  --gutter: clamp(20px, 5vw, 72px);
  --radius: 16px;
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

* {
  box-sizing: border-box;
}

html {
  background: var(--bg);
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  overflow-x: hidden;
  background: var(--bg);
  color: var(--ink);
  font-family: "Zen Maru Gothic", "Hiragino Maru Gothic ProN", "Yu Gothic UI", "Segoe UI", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
}

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

a {
  color: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  color: inherit;
  font: inherit;
}

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 4px;
}

h1,
h2,
h3,
p {
  margin-block-start: 0;
}

h1,
h2,
h3 {
  margin-block-end: 0;
  font-weight: 700;
  letter-spacing: -0.032em;
  text-wrap: balance;
}

p {
  max-width: 68ch;
  text-wrap: pretty;
}

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

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

.skip-link {
  position: fixed;
  z-index: 30;
  inset-block-start: 12px;
  inset-inline-start: 12px;
  padding: 8px 14px;
  border-radius: 999px;
  background: var(--ink);
  color: #ffffff;
  text-decoration: none;
  transform: translateY(-160%);
  transition: transform 160ms var(--ease-out);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  z-index: 20;
  inset-block-start: 0;
  border-block-end: 1px solid rgb(22 25 26 / 12%);
  background: rgb(246 247 248 / 94%);
  backdrop-filter: blur(16px);
}

.header-inner,
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-block-size: 74px;
  gap: 20px;
}

.brand,
.site-nav,
.header-actions,
.footer-links {
  display: flex;
  align-items: center;
}

.brand {
  flex: 0 0 auto;
  gap: 10px;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
}

.brand img {
  width: 40px;
  height: 40px;
  border-radius: 12px;
}

.site-nav {
  gap: clamp(14px, 2vw, 30px);
  margin-inline: auto;
  color: var(--muted);
  font-size: 14px;
}

.site-nav a,
.header-github,
.footer-links a {
  text-decoration: none;
}

.site-nav a,
.header-github,
.footer-links a,
.text-link {
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
}

.site-nav a:hover,
.header-github:hover,
.footer-links a:hover,
.text-link:hover {
  color: var(--signal);
  text-decoration: underline;
}

.header-actions {
  flex: 0 0 auto;
  gap: 16px;
  white-space: nowrap;
}

.language-toggle {
  min-block-size: 44px;
  min-inline-size: 84px;
  padding: 7px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  cursor: pointer;
  transition: border-color 160ms var(--ease-out), transform 160ms var(--ease-out);
}

.language-toggle:hover {
  border-color: var(--signal);
  transform: translateY(-1px);
}

.language-toggle:active {
  transform: scale(0.98);
}

.header-github {
  font-size: 14px;
  font-weight: 700;
}

.hero {
  min-block-size: calc(100vh - 74px);
  padding-block: clamp(72px, 9vw, 136px) clamp(72px, 10vw, 144px);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(360px, 1.1fr);
  align-items: center;
  gap: clamp(40px, 7vw, 104px);
}

.hero-copy {
  position: relative;
  z-index: 2;
  animation: hero-copy-in 640ms var(--ease-out) both;
}

.hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin-block-end: 24px;
  color: var(--signal);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  line-height: 1.4;
  text-transform: uppercase;
}

.hero-kicker span + span {
  padding-inline-start: 12px;
  border-inline-start: 1px solid var(--line);
}

h1 {
  max-width: 14ch;
  margin-block-end: 28px;
  font-size: clamp(52px, 7vw, 88px);
  line-height: 1.02;
  white-space: pre-line;
}

.hero-lead {
  max-width: 46ch;
  margin-block-end: 32px;
  color: var(--muted);
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-block-size: 52px;
  padding: 10px 22px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  font-weight: 700;
  line-height: 1.3;
  text-align: center;
  text-decoration: none;
  transition: transform 160ms var(--ease-out), background-color 160ms var(--ease-out), color 160ms var(--ease-out), border-color 160ms var(--ease-out);
}

.button:hover {
  transform: translateY(-2px);
}

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

.button-primary {
  background: var(--ink);
  color: #ffffff;
}

.button-primary:hover {
  border-color: var(--signal);
  background: var(--signal);
}

.button-secondary {
  background: transparent;
}

.button-secondary:hover {
  border-color: var(--signal);
  background: var(--surface);
  color: var(--signal);
}

.hero-facts {
  display: flex;
  max-width: 520px;
  padding: 18px 0 0;
  margin: 40px 0 0;
  border-block-start: 1px solid var(--line);
  list-style: none;
}

.hero-facts li {
  display: flex;
  flex: 1 1 0;
  flex-direction: column;
  gap: 2px;
  min-inline-size: 0;
  padding-inline: 16px;
}

.hero-facts li:first-child {
  padding-inline-start: 0;
}

.hero-facts li + li {
  border-inline-start: 1px solid var(--line);
}

.hero-facts strong {
  color: var(--signal);
  font-size: 18px;
  line-height: 1.3;
}

.hero-facts span {
  color: var(--muted);
  font-size: 13px;
}

.hero-visual {
  position: relative;
  display: grid;
  place-items: center;
  min-block-size: 650px;
  margin: 0;
  isolation: isolate;
  animation: hero-visual-in 760ms var(--ease-out) 80ms both;
}

.hero-visual-meta {
  position: absolute;
  z-index: 2;
  inset-block-start: 4%;
  inset-inline: 8% 8%;
  display: flex;
  justify-content: space-between;
  color: var(--signal);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  line-height: 1.4;
}

.hero-signal {
  position: absolute;
  z-index: -1;
  inset-block-start: 50%;
  inset-inline-start: 50%;
  width: min(720px, 132%);
  height: auto;
  overflow: visible;
  transform: translate(-50%, -50%);
}

.hero-signal path {
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.signal-line {
  stroke: var(--signal);
  stroke-width: 2.2;
  stroke-dasharray: 1300;
  stroke-dashoffset: 1300;
  animation: signal-draw 1200ms var(--ease-out) 220ms forwards;
}

.signal-baseline {
  stroke: var(--line);
  stroke-width: 1;
}

.signal-node {
  fill: var(--bg);
  stroke: var(--signal);
  stroke-width: 2;
}

.hero-visual-note {
  position: absolute;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-inline-size: 126px;
  gap: 20px;
  padding: 8px 10px;
  border-block: 1px solid var(--line);
  color: var(--signal);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.12em;
  line-height: 1.4;
}

.hero-visual-note-top {
  inset-block-start: 25%;
  inset-inline-start: 0;
}

.hero-visual-note-bottom {
  inset-block-end: 20%;
  inset-inline-end: 0;
}

.phone {
  position: relative;
  overflow: hidden;
  border: 6px solid var(--ink);
  border-radius: 32px;
  background: var(--surface);
  box-shadow: 0 18px 36px rgb(22 25 26 / 18%);
}

.phone img {
  width: 100%;
  height: auto;
}

.phone-hero {
  z-index: 1;
  width: min(52%, 330px);
  transform: rotate(2.5deg);
}

.section {
  padding-block: clamp(88px, 11vw, 156px);
  scroll-margin-block-start: 74px;
}

.section-intro {
  display: grid;
  grid-template-columns: minmax(260px, 0.9fr) minmax(260px, 0.8fr);
  align-items: end;
  gap: clamp(28px, 8vw, 120px);
  margin-block-end: 56px;
}

.section-intro h2 {
  max-width: 12ch;
  font-size: clamp(38px, 5vw, 68px);
  line-height: 1.06;
}

.section-intro p {
  margin-block-end: 4px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.75;
}

.feature-list {
  border-block-start: 1px solid var(--line);
}

.feature-row {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr) minmax(150px, 0.35fr);
  align-items: center;
  gap: clamp(20px, 3vw, 40px);
  padding-block: 28px;
  border-block-end: 1px solid var(--line);
  transition: background-color 180ms var(--ease-out), padding-inline 180ms var(--ease-out);
}

.feature-row:hover {
  padding-inline: 16px;
  background: rgb(231 238 240 / 56%);
}

.feature-mark {
  display: grid;
  place-items: center;
  inline-size: 72px;
  block-size: 72px;
  border-radius: 14px;
  background: var(--signal-pale);
}

.feature-mark img {
  width: 72px;
  height: auto;
}

.feature-row h3 {
  margin-block-end: 8px;
  font-size: clamp(21px, 2.2vw, 30px);
  line-height: 1.25;
}

.feature-row p {
  margin-block-end: 0;
  color: var(--muted);
}

.feature-side {
  justify-self: end;
  color: var(--signal);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  line-height: 1.5;
  text-align: end;
}

.section-dark {
  background: var(--dark);
  color: #ffffff;
}

.workflow-head {
  max-width: 760px;
  margin-block-end: 68px;
}

.workflow-marker,
.privacy-label {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-block-end: 20px;
  color: var(--dark-muted);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.5;
  text-transform: uppercase;
}

.workflow-dot,
.privacy-label-dot {
  inline-size: 8px;
  block-size: 8px;
  border-radius: 50%;
  background: var(--signal);
}

.workflow-head h2 {
  max-width: 10ch;
  margin-block-end: 20px;
  font-size: clamp(44px, 6vw, 78px);
  line-height: 1.02;
}

.workflow-head > p:last-child {
  margin-block-end: 0;
  color: var(--dark-muted);
  font-size: 19px;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  padding: 0;
  margin: 0;
  list-style: none;
}

.step {
  min-block-size: 250px;
  padding: 24px clamp(18px, 4vw, 48px) 24px 0;
  border-block-start: 1px solid var(--dark-line);
}

.step + .step {
  padding-inline-start: clamp(18px, 4vw, 48px);
  border-inline-start: 1px solid var(--dark-line);
}

.step-number {
  display: block;
  margin-block-end: 42px;
  color: var(--signal);
  font-size: 30px;
  font-variant-numeric: tabular-nums;
  line-height: 1;
}

.step h3 {
  margin-block-end: 12px;
  font-size: clamp(21px, 2.3vw, 30px);
  line-height: 1.2;
}

.step p {
  margin-block-end: 0;
  color: var(--dark-muted);
}

.screens-section {
  background: var(--surface);
}

.screen-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  align-items: start;
  gap: clamp(12px, 2vw, 24px);
}

.screen-card {
  grid-column: span 2;
  min-width: 0;
  margin: 0;
}

.screen-card-featured {
  grid-column: span 6;
}

.screen-frame {
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg);
  transition: border-color 180ms var(--ease-out), background-color 180ms var(--ease-out);
}

.screen-card-featured .screen-frame {
  border-color: var(--signal);
  background: var(--signal-pale);
}

.screen-card:hover .screen-frame {
  border-color: var(--signal);
}

.phone-screen {
  border-width: 4px;
  border-radius: 22px;
  box-shadow: none;
}

.screen-card figcaption {
  display: grid;
  gap: 2px;
  padding-block-start: 16px;
}

.screen-card figcaption strong {
  font-size: 16px;
  line-height: 1.4;
}

.screen-card figcaption span {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.section-paper {
  background: var(--paper);
}

.privacy-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.8fr) minmax(360px, 1.2fr);
  align-items: center;
  gap: clamp(48px, 9vw, 140px);
}

.privacy-label {
  color: var(--signal);
}

.privacy-copy h2 {
  max-width: 10ch;
  margin-block-end: 22px;
  font-size: clamp(40px, 5vw, 68px);
  line-height: 1.04;
}

.privacy-copy > p:not(.privacy-label) {
  margin-block-end: 28px;
  color: var(--muted);
  font-size: 18px;
}

.text-link {
  color: var(--signal);
  font-weight: 700;
}

.privacy-detail {
  min-width: 0;
}

.privacy-detail > img {
  width: min(100%, 520px);
  margin-inline: auto;
  margin-block-end: 20px;
}

.privacy-list {
  padding: 0;
  margin: 0;
  list-style: none;
}

.privacy-list li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 20px;
  padding-block: 14px;
  border-block-start: 1px solid rgb(65 76 80 / 26%);
  font-size: clamp(17px, 2vw, 22px);
}

.privacy-list li > span:last-child {
  flex: 0 0 auto;
  color: var(--signal);
}

.faq-layout {
  display: grid;
  grid-template-columns: minmax(240px, 0.7fr) minmax(0, 1fr);
  align-items: start;
  gap: clamp(48px, 10vw, 160px);
}

.faq-layout .section-intro {
  display: block;
  margin-block-end: 0;
}

.faq-layout .section-intro h2 {
  max-width: 10ch;
  margin-block-end: 20px;
}

.faq-list {
  border-block-start: 1px solid var(--line);
}

details {
  border-block-end: 1px solid var(--line);
}

summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-block-size: 76px;
  gap: 20px;
  padding-block: 16px;
  cursor: pointer;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.45;
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

summary::after {
  flex: 0 0 auto;
  content: "+";
  color: var(--signal);
  font-size: 26px;
  font-weight: 400;
  line-height: 1;
}

details[open] summary::after {
  content: "−";
}

details p {
  max-inline-size: 64ch;
  padding-block-end: 24px;
  margin-block: 0;
  color: var(--muted);
}

.final-cta {
  padding-block: clamp(88px, 11vw, 136px);
  background: var(--signal-pale);
  text-align: center;
}

.final-cta-inner {
  display: grid;
  justify-items: center;
}

.cta-mark {
  width: min(180px, 42vw);
  margin-block-end: 28px;
}

.cta-mark path {
  fill: none;
  stroke: var(--signal);
  stroke-linecap: round;
  stroke-width: 1.5;
}

.cta-mark circle {
  fill: var(--signal-pale);
  stroke: var(--signal);
  stroke-width: 1.5;
}

.final-cta h2 {
  max-width: 12ch;
  margin-inline: auto;
  margin-block-end: 18px;
  font-size: clamp(42px, 6vw, 78px);
  line-height: 1.04;
}

.final-cta p {
  margin-block-end: 30px;
  color: var(--muted);
  font-size: 18px;
}

.site-footer {
  background: var(--surface);
  color: var(--muted);
  font-size: 13px;
}

.footer-inner {
  min-block-size: 96px;
}

.footer-inner > div:first-child {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
}

.footer-inner strong {
  color: var(--ink);
}

.footer-meta {
  color: var(--muted);
}

.footer-links {
  gap: 20px;
}

@keyframes hero-copy-in {
  from {
    opacity: 0;
    transform: translateY(16px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes hero-visual-in {
  from {
    opacity: 0;
    transform: translateY(14px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes signal-draw {
  to {
    stroke-dashoffset: 0;
  }
}

@media (max-width: 980px) {
  .site-nav {
    display: none;
  }

  .hero-grid {
    grid-template-columns: 1fr;
  }

  .hero-copy {
    max-width: 720px;
  }

  .hero-visual {
    min-block-size: 560px;
  }

  .phone-hero {
    width: min(46%, 320px);
  }

  .section-intro,
  .privacy-layout,
  .faq-layout {
    grid-template-columns: 1fr;
  }

  .section-intro {
    gap: 20px;
  }

  .section-intro h2,
  .privacy-copy h2,
  .faq-layout .section-intro h2 {
    max-width: 18ch;
  }

  .feature-row {
    grid-template-columns: 84px minmax(0, 1fr);
  }

  .feature-side {
    grid-column: 2;
    justify-self: start;
    text-align: start;
  }

  .steps {
    grid-template-columns: 1fr;
  }

  .step,
  .step + .step {
    min-block-size: auto;
    padding: 28px 0;
    border-inline-start: 0;
  }

  .step-number {
    margin-block-end: 22px;
  }

  .screen-grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .screen-card-featured {
    grid-column: span 6;
  }

  .screen-card:not(.screen-card-featured) {
    grid-column: span 2;
  }

  .privacy-detail > img {
    margin-inline: 0 auto;
  }
}

@media (max-width: 640px) {
  :root {
    --gutter: 20px;
  }

  .header-inner {
    min-block-size: 68px;
  }

  .header-actions {
    gap: 10px;
  }

  .header-github {
    display: none;
  }

  .hero {
    min-block-size: auto;
    padding-block-start: 64px;
  }

  h1 {
    max-width: 12ch;
    font-size: clamp(44px, 13vw, 68px);
  }

  .hero-lead {
    font-size: 18px;
  }

  .hero-actions,
  .hero-actions .button {
    inline-size: 100%;
  }

  .hero-facts {
    gap: 0;
  }

  .hero-facts li {
    padding-inline: 10px;
  }

  .hero-facts li:first-child {
    padding-inline-start: 0;
  }

  .hero-facts strong {
    font-size: 16px;
  }

  .hero-facts span {
    font-size: 12px;
  }

  .hero-visual {
    min-block-size: 470px;
  }

  .hero-visual-meta {
    inset-inline: 0;
    font-size: 10px;
  }

  .hero-signal {
    width: 155%;
  }

  .hero-visual-note {
    display: none;
  }

  .phone-hero {
    width: min(63%, 290px);
  }

  .section {
    padding-block: 88px;
    scroll-margin-block-start: 68px;
  }

  .section-intro {
    margin-block-end: 40px;
  }

  .section-intro h2,
  .privacy-copy h2,
  .faq-layout .section-intro h2 {
    font-size: clamp(36px, 11vw, 54px);
  }

  .section-intro p,
  .privacy-copy > p:not(.privacy-label),
  .workflow-head > p:last-child,
  .final-cta p {
    font-size: 17px;
  }

  .feature-row {
    grid-template-columns: 68px minmax(0, 1fr);
    gap: 16px;
    padding-block: 24px;
  }

  .feature-row:hover {
    padding-inline: 0;
    background: transparent;
  }

  .feature-mark,
  .feature-mark img {
    inline-size: 64px;
    block-size: 64px;
  }

  .feature-row h3 {
    font-size: 22px;
  }

  .feature-side {
    grid-column: 2;
    margin-block-start: -4px;
  }

  .workflow-head {
    margin-block-end: 48px;
  }

  .workflow-head h2 {
    font-size: clamp(42px, 12vw, 62px);
  }

  .screen-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }

  .screen-card-featured,
  .screen-card:not(.screen-card-featured) {
    grid-column: span 2;
  }

  .screen-card:not(.screen-card-featured) {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: start;
    gap: 12px;
  }

  .screen-card:not(.screen-card-featured) figcaption {
    padding-block-start: 8px;
  }

  .screen-card:not(.screen-card-featured) .screen-frame {
    padding: 8px;
  }

  .privacy-layout {
    gap: 40px;
  }

  .privacy-list li {
    font-size: 17px;
  }

  .faq-layout {
    gap: 40px;
  }

  summary {
    min-block-size: 72px;
    font-size: 17px;
  }

  details p {
    font-size: 16px;
  }

  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    gap: 12px;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}

@media print {
  .site-header {
    position: static;
    background: transparent;
  }

  .hero,
  .section {
    min-block-size: auto;
    padding-block: 40px;
  }

  .hero-visual-note,
  .hero-signal,
  .language-toggle {
    display: none;
  }
}