:root {
  --ground: #f6f7fb;
  --surface: #ffffff;
  --surface-2: #eef0f7;
  --ink: #0f1320;
  --ink-soft: #4a4f63;
  --ink-faint: #8a8fa3;
  --line: #e1e4ef;
  --accent: #2c4bff;
  --accent-ink: #1c33c4;
  --ok: #1fb77e;
  --warn: #e4952b;
  --maxw: 780px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ground: #0b0e18;
    --surface: #131726;
    --surface-2: #1b2032;
    --ink: #eef0f7;
    --ink-soft: #a9aec2;
    --ink-faint: #6a7089;
    --line: #262c40;
    --accent: #5c77ff;
    --accent-ink: #8298ff;
    --ok: #35c98f;
    --warn: #f0a94a;
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

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

body {
  margin: 0;
  font-family: var(--font);
  background: var(--ground);
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
  line-height: 1.7;
}

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

a:hover {
  text-decoration: underline;
}

header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: saturate(180%) blur(14px);
  background: color-mix(in srgb, var(--ground) 82%, transparent);
  border-bottom: 1px solid var(--line);
}

.nav {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  font-weight: 800;
  letter-spacing: -0.02em;
  font-size: 18px;
  color: var(--ink);
}

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

.mark {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: linear-gradient(145deg, var(--accent), var(--accent-ink));
  display: grid;
  place-items: center;
  color: #fff;
  font-weight: 800;
  font-size: 17px;
}

.back {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-soft);
}

.back:hover {
  color: var(--ink);
  text-decoration: none;
}

main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 56px 24px 40px;
}

.app-badge {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 12px 16px;
  margin-bottom: 24px;
}

.app-icon {
  width: 44px;
  height: 44px;
  border-radius: 11px;
  background: linear-gradient(150deg, #2cb5ff, #2c4bff);
  display: grid;
  place-items: center;
  font-size: 22px;
}

.app-badge b {
  display: block;
  font-size: 15px;
  color: var(--ink);
  font-weight: 700;
}

.app-badge span {
  font-size: 13px;
  color: var(--ink-faint);
}

.eyebrow {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 14px;
}

h1 {
  font-size: clamp(28px, 5vw, 42px);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin: 0 0 12px;
  text-wrap: balance;
}

.updated {
  color: var(--ink-faint);
  font-size: 14px;
  margin: 0 0 20px;
}

.intro {
  color: var(--ink-soft);
  font-size: 17px;
  margin: 0 0 8px;
}

h2 {
  font-size: 21px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 40px 0 12px;
}

h2 .num {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  margin-right: 8px;
}

h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  margin: 18px 0 6px;
}

p {
  color: var(--ink-soft);
  margin: 0 0 14px;
}

ul {
  color: var(--ink-soft);
  margin: 0 0 14px;
  padding-left: 22px;
}

li {
  margin-bottom: 8px;
}

strong {
  color: var(--ink);
  font-weight: 700;
}

.callout {
  background: color-mix(in srgb, var(--ok) 10%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--ok) 40%, var(--line));
  border-radius: 14px;
  padding: 18px 20px;
  margin: 22px 0;
}

.callout p {
  margin: 0;
  font-size: 15px;
  color: var(--ink);
}

.callout b {
  color: var(--ok);
}

.summary {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 8px 22px;
  margin: 20px 0;
}

.summary ul {
  list-style: none;
  padding: 0;
  margin: 14px 0;
}

.summary li {
  position: relative;
  padding-left: 30px;
}

.summary li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--ok);
  font-weight: 800;
}

.safety {
  background: color-mix(in srgb, var(--warn) 12%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--warn) 45%, var(--line));
  border-radius: 14px;
  padding: 18px 22px;
  margin: 18px 0;
}

.safety h3 {
  margin-top: 0;
}

.safety h3::before {
  content: "⚠ ";
  color: var(--warn);
}

.safety p:last-child {
  margin-bottom: 0;
}

.contact-box {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 22px;
  margin-top: 8px;
}

.contact-box div {
  margin-bottom: 6px;
  font-size: 15px;
  color: var(--ink);
}

.contact-box b {
  color: var(--ink-faint);
  font-weight: 700;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  display: inline-block;
  width: 84px;
  vertical-align: top;
}

footer {
  border-top: 1px solid var(--line);
  margin-top: 32px;
  padding: 32px 24px;
  color: var(--ink-faint);
  font-size: 14px;
}

.foot {
  max-width: var(--maxw);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
}

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

.foot .links {
  display: flex;
  gap: 20px;
}

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

@media (max-width: 520px) {
  .back {
    display: none;
  }

  .contact-box b {
    display: block;
    width: auto;
    margin-bottom: 2px;
  }
}