/* Air Tactics site — same instrument-panel palette as the app. No external fonts or scripts. */
:root {
  --bg: #04121b;
  --panel: #0a2130;
  --panel-2: #0e2a3c;
  --line: rgba(99, 222, 240, 0.16);
  --aqua: #63def0;
  --coral: #fa6e6b;
  --amber: #f5b544;
  --text: #e8f4f8;
  --muted: #9bb4c0;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 17px/1.65 var(--sans);
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 64px 64px;
  background-position: center top;
  background-attachment: fixed;
}
body::before { /* fade the grid toward the edges */
  content: ""; position: fixed; inset: 0; pointer-events: none; z-index: -1;
  background: radial-gradient(ellipse at 50% 20%, transparent 0%, var(--bg) 75%);
}
a { color: var(--aqua); text-underline-offset: 3px; }
a:hover { color: #fff; }
img { max-width: 100%; height: auto; display: block; }

/* Bilingual: every string exists twice; <html lang> picks one. */
html[lang="en"] .zh, html[lang="zh-Hans"] .en { display: none !important; }

.wrap { width: min(1080px, 100% - 32px); margin-inline: auto; }

/* Top bar */
.bar { position: sticky; top: 0; z-index: 10; backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  background: rgba(4, 18, 27, 0.78); border-bottom: 1px solid var(--line); }
.bar .wrap { display: flex; align-items: center; gap: 16px; height: 60px; }
.brand { white-space: nowrap; flex: none; display: flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none;
  font-weight: 800; letter-spacing: 0.08em; font-size: 15px; }
.brand img { width: 30px; height: 30px; border-radius: 7px; }
.bar nav { margin-left: auto; display: flex; gap: 18px; align-items: center; }
.bar nav a { color: var(--muted); text-decoration: none; font: 600 13px/1 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; }
.bar nav a:hover, .bar nav a[aria-current="page"] { color: var(--aqua); }
.lang { white-space: nowrap; flex: none; font: 600 13px/1 var(--mono); color: var(--text); background: transparent; border: 1px solid var(--line);
  border-radius: 8px; padding: 8px 10px; cursor: pointer; min-height: 36px; }
.lang:hover { border-color: var(--aqua); }

/* Hero */
.hero { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: center; padding: 72px 0 56px; }
.eyebrow { font: 600 13px/1 var(--mono); letter-spacing: 0.16em; color: var(--aqua); text-transform: uppercase; }
h1 { font-size: clamp(44px, 7vw, 76px); line-height: 1; margin: 16px 0 20px; letter-spacing: 0.02em; font-weight: 900; }
.lede { font-size: 20px; color: var(--muted); max-width: 34em; margin: 0 0 28px; }
.lede strong { color: var(--text); font-weight: 600; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.btn { display: inline-flex; align-items: center; gap: 10px; min-height: 48px; padding: 0 22px; border-radius: 12px;
  font-weight: 700; text-decoration: none; }
.btn.primary { background: var(--aqua); color: #04121b; }
.btn.primary:hover { background: #8beaf6; color: #04121b; }
.btn.ghost { border: 1px solid var(--line); color: var(--text); }
.btn.ghost:hover { border-color: var(--aqua); }
.note { font: 13px/1.5 var(--mono); color: var(--muted); margin-top: 14px; }
.hero-art { position: relative; border-radius: 28px; overflow: hidden; border: 1px solid var(--line);
  aspect-ratio: 2 / 3; box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5); }
.hero-art img { width: 100%; height: 100%; object-fit: cover; object-position: center 70%; }
.hero-art .tag { position: absolute; left: 16px; bottom: 16px; font: 600 12px/1 var(--mono); letter-spacing: 0.12em;
  background: rgba(4, 18, 27, 0.72); border: 1px solid var(--line); padding: 8px 10px; border-radius: 8px; color: var(--aqua); }

/* Sections */
section { padding: 56px 0; }
h2 { font-size: clamp(28px, 4vw, 38px); margin: 0 0 12px; line-height: 1.15; }
.sub { color: var(--muted); margin: 0 0 32px; max-width: 40em; }

/* Round loop: four numbered steps like the in-game training */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; counter-reset: step; }
.step { background: var(--panel); border: 1px solid var(--line); border-radius: 16px; padding: 20px; }
.step .k { font: 700 12px/1 var(--mono); letter-spacing: 0.14em; color: var(--amber); }
.step h3 { margin: 10px 0 6px; font-size: 19px; }
.step p { margin: 0; color: var(--muted); font-size: 15px; }
.step .cost { display: inline-block; margin-top: 12px; font: 600 12px/1 var(--mono); color: var(--aqua);
  border: 1px solid var(--line); border-radius: 6px; padding: 6px 8px; }

/* Screens */
.shots { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.shot figure { margin: 0; }
.shot img { border-radius: 22px; border: 1px solid var(--line); background: var(--panel); aspect-ratio: 1206 / 2622; width: 100%; }
.shot figcaption { margin-top: 12px; font-size: 15px; color: var(--muted); }
.shot figcaption b { color: var(--text); display: block; font-size: 16px; }

/* Feature list: plain rows, not cards */
.features { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0 48px; border-top: 1px solid var(--line); }
.feature { padding: 22px 0; border-bottom: 1px solid var(--line); display: grid; grid-template-columns: 28px 1fr; gap: 14px; }
.feature .dot { width: 10px; height: 10px; border-radius: 50%; background: var(--aqua); margin-top: 9px; box-shadow: 0 0 12px var(--aqua); }
.feature.warn .dot { background: var(--coral); box-shadow: 0 0 12px var(--coral); }
.feature h3 { margin: 0 0 4px; font-size: 17px; }
.feature p { margin: 0; color: var(--muted); font-size: 15px; }

/* Long-form pages (privacy, support) */
.doc { max-width: 760px; padding: 56px 0 72px; }
.doc h1 { font-size: clamp(36px, 6vw, 52px); }
.doc h2 { font-size: 22px; margin: 40px 0 10px; }
.doc p, .doc li { color: #c9dbe2; }
.doc ul { padding-left: 1.2em; }
.doc li { margin: 6px 0; }
.doc .meta { font: 13px/1.5 var(--mono); color: var(--muted); }
.summary { background: var(--panel); border: 1px solid var(--line); border-left: 3px solid var(--aqua); border-radius: 12px;
  padding: 18px 20px; margin: 24px 0; }
.summary p { margin: 0; color: var(--text); }
table { width: 100%; border-collapse: collapse; font-size: 15px; margin: 12px 0; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font: 600 12px/1.4 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); }
details { border-bottom: 1px solid var(--line); padding: 16px 0; }
details summary { cursor: pointer; font-weight: 600; list-style: none; display: flex; justify-content: space-between; gap: 16px; }
details summary::-webkit-details-marker { display: none; }
details summary::after { content: "+"; font-family: var(--mono); color: var(--aqua); }
details[open] summary::after { content: "–"; }
details p { margin: 10px 0 0; }
.contact { display: flex; flex-wrap: wrap; gap: 16px; align-items: center; background: var(--panel-2);
  border: 1px solid var(--line); border-radius: 16px; padding: 22px; margin: 28px 0; }
.contact .mail { font: 600 18px/1.3 var(--mono); word-break: break-all; }

footer { border-top: 1px solid var(--line); padding: 28px 0 40px; color: var(--muted); font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 12px 24px; align-items: center; }
footer nav { display: flex; gap: 18px; margin-left: auto; }
footer a { color: var(--muted); }

@media (max-width: 860px) {
  .hero { grid-template-columns: 1fr; gap: 32px; padding: 40px 0 32px; }
  .hero-art { max-width: 420px; aspect-ratio: 4 / 5; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .shots { grid-template-columns: repeat(2, 1fr); }
  .features { grid-template-columns: 1fr; }
}
@media (max-width: 520px) {
  body { font-size: 16px; }
  .bar nav a.hide-sm { display: none; }
  .bar nav a { white-space: nowrap; }
  .bar nav { gap: 12px; }
  .lede { font-size: 18px; }
  .steps { grid-template-columns: 1fr; }
  .shots { gap: 12px; }
  footer nav { margin-left: 0; }
}
@media (max-width: 400px) {
  html[lang="en"] .brand-name { display: none; }
}
@media (prefers-reduced-motion: no-preference) {
  .btn, .lang, .bar nav a { transition: background-color 0.15s, border-color 0.15s, color 0.15s; }
}