:root {
  --bg: #ffffff;
  --bg-soft: #f5f7fa;
  --bg-card: #ffffff;
  --fg: #1b1f24;
  --fg-soft: #5b6472;
  --line: #e2e6ec;
  --blue: #2f6fd0;
  --blue-dark: #2559ab;
  --green: #2e9e4f;
  --green-dark: #24803f;
  --radius: 14px;
  --max: 1120px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", "PingFang SC", "Hiragino Sans", "Noto Sans", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1319;
    --bg-soft: #151a22;
    --bg-card: #171d26;
    --fg: #eef2f7;
    --fg-soft: #a4afbe;
    --line: #272f3b;
    --blue: #5b93e8;
    --blue-dark: #3f79d1;
    --green: #45b96a;
    --green-dark: #2f9a52;
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3 {
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin: 0 0 12px;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.1rem);
}

h2 {
  font-size: clamp(1.5rem, 3.2vw, 2.1rem);
}

h3 {
  font-size: 1.08rem;
}

p {
  margin: 0 0 14px;
}

a {
  color: var(--blue);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.icon {
  width: 22px;
  height: 22px;
  flex: none;
}

.skip {
  position: absolute;
  left: -9999px;
}

.skip:focus {
  left: 12px;
  top: 12px;
  z-index: 20;
  background: var(--bg-card);
  padding: 8px 14px;
  border-radius: 8px;
}

/* Header */
.lang-hint {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  padding: 10px 16px;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--line);
  font-size: 0.92rem;
}

.lang-hint a {
  color: var(--blue);
  font-weight: 600;
}

.lang-hint-x {
  border: 0;
  padding: 2px 6px;
  background: none;
  color: var(--fg-soft);
  font: inherit;
  font-size: 1.15rem;
  line-height: 1;
  cursor: pointer;
}

.lang-hint-x:hover {
  color: var(--fg);
}

.site-head {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 12px max(20px, calc((100vw - var(--max)) / 2));
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
  color: var(--fg);
  white-space: nowrap;
}

.brand-icon {
  width: 30px;
  height: 30px;
}

.site-nav {
  display: flex;
  gap: 20px;
  margin-inline-start: auto;
  font-size: 0.95rem;
}

.site-nav a {
  color: var(--fg-soft);
}

.site-nav a:hover {
  color: var(--fg);
}

.langs details {
  position: relative;
}

.langs summary {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  list-style: none;
  color: var(--fg-soft);
  font-size: 0.95rem;
}

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

.langs ul {
  position: absolute;
  inset-inline-end: 0;
  top: calc(100% + 10px);
  margin: 0;
  padding: 6px;
  min-width: 168px;
  list-style: none;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: 0 12px 32px rgb(0 0 0 / 14%);
}

.langs li a {
  display: block;
  padding: 7px 12px;
  border-radius: 8px;
  color: var(--fg);
  font-size: 0.94rem;
}

.langs li a:hover {
  background: var(--bg-soft);
  text-decoration: none;
}

.langs li a[aria-current] {
  color: var(--blue);
  font-weight: 600;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 11px 22px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.98rem;
  white-space: nowrap;
}

.btn:hover {
  text-decoration: none;
}

.btn.primary {
  background: var(--blue);
  color: #fff;
}

.btn.primary:hover {
  background: var(--blue-dark);
}

.btn.ghost {
  border: 1px solid var(--line);
  color: var(--fg);
}

.btn.ghost:hover {
  background: var(--bg-soft);
}

/* Layout */
.hero,
.section,
.cta {
  padding: 64px max(20px, calc((100vw - var(--max)) / 2));
}

.hero {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 48px;
  align-items: center;
  padding-top: 56px;
  padding-bottom: 40px;
}

.eyebrow {
  color: var(--green);
  font-weight: 700;
  font-size: 0.86rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 10px;
}

.lede {
  color: var(--fg-soft);
  font-size: 1.12rem;
  max-width: 46ch;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 24px 0 14px;
}

.hero-note {
  color: var(--fg-soft);
  font-size: 0.9rem;
  margin: 0;
}

.section-lede {
  color: var(--fg-soft);
  max-width: 62ch;
  margin-bottom: 32px;
}

.section:nth-of-type(even) {
  background: var(--bg-soft);
}

/* Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
}

.card p {
  color: var(--fg-soft);
  font-size: 0.96rem;
  margin: 0;
}

.card-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 11px;
  background: color-mix(in srgb, var(--blue) 12%, transparent);
  color: var(--blue);
  margin-bottom: 14px;
}

.card.mode .card-icon {
  background: color-mix(in srgb, var(--green) 14%, transparent);
  color: var(--green);
}

/* Showcase */
.showcase {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 44px;
  align-items: center;
  padding: 30px 0;
  border-top: 1px solid var(--line);
}

.showcase.reverse .showcase-art {
  order: -1;
}

.showcase-text p {
  color: var(--fg-soft);
}

.ticks {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.ticks li {
  position: relative;
  padding-inline-start: 26px;
  color: var(--fg-soft);
  font-size: 0.97rem;
}

.ticks li::before {
  content: "";
  position: absolute;
  inset-inline-start: 0;
  top: 0.42em;
  width: 14px;
  height: 8px;
  border-inline-start: 2px solid var(--green);
  border-bottom: 2px solid var(--green);
  transform: rotate(-45deg);
}

/* Steps */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: step;
}

.step {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
}

.step p {
  color: var(--fg-soft);
  font-size: 0.96rem;
  margin: 0;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--green);
  color: #fff;
  font-weight: 700;
  margin-bottom: 12px;
}

/* Privacy */
.privacy {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

/* FAQ */
.faq {
  display: grid;
  gap: 10px;
  max-width: 860px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 18px;
}

.faq-item summary {
  cursor: pointer;
  font-weight: 600;
}

.faq-item p {
  color: var(--fg-soft);
  margin: 10px 0 0;
  font-size: 0.97rem;
}

/* CTA */
.cta {
  text-align: center;
  background: var(--bg-soft);
  border-top: 1px solid var(--line);
}

.cta p {
  color: var(--fg-soft);
  max-width: 52ch;
  margin: 0 auto 22px;
}

.qr {
  margin: 30px auto 0;
  display: grid;
  justify-items: center;
  gap: 10px;
}

.qr img {
  display: block;
  width: 160px;
  height: 160px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 8px;
}

.qr figcaption {
  color: var(--fg-soft);
  font-size: 0.88rem;
}

/* Footer */
.site-foot {
  padding: 40px max(20px, calc((100vw - var(--max)) / 2));
  border-top: 1px solid var(--line);
  font-size: 0.92rem;
}

.foot-brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
}

.foot-tagline {
  color: var(--fg-soft);
  margin: 10px 0 16px;
  max-width: 52ch;
}

.foot-links,
.foot-langs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-bottom: 14px;
}

.foot-langs a {
  color: var(--fg-soft);
}

.foot-copy {
  color: var(--fg-soft);
  margin: 0;
}

/* App UI mockups */
.mock {
  margin: 0;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px;
  box-shadow: 0 18px 44px rgb(15 25 45 / 12%);
  font-size: 0.86rem;
  display: grid;
  gap: 12px;
}

.mk-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.mk-logo {
  width: 32px;
  height: 32px;
}

.mk-tools {
  display: flex;
  gap: 12px;
  margin-inline-start: auto;
  color: var(--fg-soft);
}

.mk-field {
  border: 1px solid var(--line);
  border-radius: 9px;
  padding: 11px 13px;
  color: var(--fg-soft);
  background: var(--bg);
}

.mk-field.filled {
  color: var(--fg);
  display: block;
  margin-top: 5px;
}

.mk-checks {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
}

.mk-checks.col {
  flex-direction: column;
  gap: 9px;
}

.mk-check {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--fg-soft);
}

.mk-box {
  width: 16px;
  height: 16px;
  border: 2px solid var(--fg-soft);
  border-radius: 5px;
  flex: none;
}

.mk-check.on {
  color: var(--fg);
}

.mk-check.on .mk-box {
  background-color: var(--blue);
  border-color: var(--blue);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23fff' stroke-width='3.4' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m5 12.5 5 5 9-10'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: center;
  background-size: 100% 100%;
}

.mk-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.mk-actions.start {
  display: flex;
  flex-wrap: wrap;
}

.mk-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 16px;
  border-radius: 8px;
  color: #fff;
  font-weight: 700;
}

.mk-btn.blue {
  background: var(--blue);
}

.mk-btn.green {
  background: var(--green-dark);
}

.mk-btn.sm {
  padding: 6px 14px;
  font-size: 0.8rem;
  font-weight: 600;
}

.mk-list {
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
}

.mk-list-head {
  background: var(--bg-soft);
  padding: 10px 14px;
  font-weight: 700;
}

.mk-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 14px;
  border-top: 1px solid var(--line);
}

.mk-name {
  margin-inline-end: auto;
}

.mk-ic.folder {
  color: var(--blue);
}

.mk-ic.doc {
  color: var(--fg-soft);
}

.mk-more {
  display: inline-flex;
  color: var(--fg-soft);
}

.mk-dialog-title {
  text-align: center;
  font-weight: 700;
  font-size: 1rem;
}

.mk-legend {
  display: block;
  color: var(--fg-soft);
  font-size: 0.78rem;
}

.mk-hint {
  color: var(--fg-soft);
  font-size: 0.78rem;
  margin: 0;
}

.mock-popup,
.mock-dialog {
  max-width: 400px;
  margin-inline: auto;
}

.mock-rules {
  max-width: 470px;
  margin-inline: auto;
}

@media (max-width: 900px) {
  .hero,
  .showcase,
  .privacy {
    grid-template-columns: 1fr;
  }

  .showcase.reverse .showcase-art {
    order: 0;
  }

  .cards,
  .steps {
    grid-template-columns: repeat(2, 1fr);
  }

  .site-nav {
    display: none;
  }

  .langs {
    margin-inline-start: auto;
  }
}

@media (max-width: 620px) {
  body {
    font-size: 16px;
  }

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

  .hero,
  .section,
  .cta,
  .site-foot {
    padding-block: 44px;
  }
}

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