/* ============================================================
   REALITY CHECK · 实事求是 — companion ledger
   Palette: steel void, amber (warning/truth), red severity
   ============================================================ */
:root {
  --void: #07080c; --panel: #11131c; --ink: #eef1f7; --ink-dim: #9aa3b8;
  --ink-faint: #5a6178; --amber: #f5a623; --amber-deep: #b9760a;
  --red: #e8233a; --green: #34d399; --cyan: #3fe3ff;
  --line: rgba(255,255,255,0.08); --line-2: rgba(255,255,255,0.14);
  --maxw: 1140px; --ease: cubic-bezier(0.22,1,0.36,1);
  --serif: "Noto Serif SC", serif; --sans: "Space Grotesk", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background:
    radial-gradient(1100px 700px at 82% -10%, rgba(245,166,35,0.14), transparent 60%),
    radial-gradient(900px 700px at 0% 110%, rgba(232,35,58,0.08), transparent 60%),
    var(--void);
  color: var(--ink); font-family: var(--sans); font-weight: 300; line-height: 1.6;
  -webkit-font-smoothing: antialiased; overflow-x: hidden; min-height: 100vh;
}
::selection { background: var(--amber); color: #1a1300; }
a { color: inherit; text-decoration: none; }
.grain { position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background: repeating-linear-gradient(to bottom, transparent 0 3px, rgba(0,0,0,0.18) 3px 4px);
  mix-blend-mode: overlay; opacity: 0.4; }

/* Nav */
.nav { position: fixed; inset: 0 0 auto 0; z-index: 50; display: flex; align-items: center;
  justify-content: space-between; padding: 18px clamp(20px,5vw,52px);
  backdrop-filter: blur(10px); background: linear-gradient(to bottom, rgba(7,8,12,0.85), rgba(7,8,12,0));
  border-bottom: 1px solid transparent; transition: border-color .4s, background .4s; }
.nav.scrolled { border-bottom-color: var(--line); background: rgba(7,8,12,0.92); }
.brand { display: flex; align-items: center; gap: 12px; letter-spacing: 0.14em; }
.brand-mark { font-family: var(--serif); font-weight: 900; font-size: 21px; width: 38px; height: 38px;
  display: grid; place-items: center; color: #1a1300; background: linear-gradient(135deg, var(--amber), var(--amber-deep));
  border-radius: 9px; box-shadow: 0 0 22px rgba(245,166,35,0.5); }
.brand-mark.small { width: 30px; height: 30px; font-size: 16px; }
.brand-text { font-weight: 700; font-size: 14.5px; }
.brand-text i { color: var(--ink-faint); font-style: normal; font-weight: 400; margin-left: 6px; }
.nav-links { display: flex; gap: clamp(14px,2.4vw,30px); }
.nav-links a { font-size: 12.5px; letter-spacing: 0.08em; color: var(--ink-dim); text-transform: uppercase;
  position: relative; padding: 4px 0; transition: color .25s; }
.nav-links a::after { content: ""; position: absolute; left: 0; bottom: -2px; height: 1px; width: 0;
  background: var(--amber); transition: width .3s var(--ease); }
.nav-links a:hover { color: var(--ink); } .nav-links a:hover::after { width: 100%; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 8px; margin: -8px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--ink); border-radius: 2px; transition: transform .3s var(--ease), opacity .2s; }
.nav.open .nav-toggle span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav.open .nav-toggle span:nth-child(2) { opacity: 0; }
.nav.open .nav-toggle span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
@media (max-width: 680px) {
  .nav-toggle { display: flex; }
  .nav-links { position: absolute; top: 100%; left: 0; right: 0; flex-direction: column; gap: 0;
    background: rgba(7,8,12,0.97); backdrop-filter: blur(12px); border-bottom: 1px solid var(--line);
    padding: 8px clamp(20px,5vw,52px) 18px; opacity: 0; visibility: hidden; transform: translateY(-8px);
    transition: opacity .25s, transform .25s var(--ease), visibility .25s; }
  .nav.open .nav-links { opacity: 1; visibility: visible; transform: none; }
  .nav-links a { padding: 13px 0; font-size: 15px; border-bottom: 1px solid var(--line); }
  .nav-links a:last-child { border-bottom: 0; }
}

/* Hero */
.hero { max-width: var(--maxw); margin: 0 auto; padding: 150px clamp(20px,5vw,52px) 70px; }
.kicker { font-family: var(--mono); font-size: 12px; letter-spacing: 0.22em; color: var(--amber);
  text-transform: uppercase; margin-bottom: 26px; display: flex; align-items: center; gap: 10px; }
.kicker .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--amber);
  box-shadow: 0 0 14px var(--amber); animation: pulse 2s infinite; }
@keyframes pulse { 50% { opacity: .35; transform: scale(.7); } }
.hero h1 { font-weight: 600; font-size: clamp(40px,8vw,86px); line-height: 1.02; letter-spacing: -0.02em; margin-bottom: 28px; }
.grad { background: linear-gradient(100deg, var(--amber), #ffe08a 75%); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-sub { max-width: 680px; font-size: clamp(15px,1.9vw,19px); color: var(--ink-dim); margin-bottom: 36px; }
.hero-sub strong { color: var(--amber); font-weight: 500; }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 60px; }
.btn { font-weight: 500; font-size: 15px; padding: 14px 24px; border-radius: 10px; border: 1px solid transparent;
  transition: transform .25s var(--ease), box-shadow .25s, background .25s; }
.btn.primary { background: linear-gradient(120deg, var(--amber), var(--amber-deep)); color: #1a1300;
  box-shadow: 0 10px 40px -12px rgba(245,166,35,0.7); }
.btn.primary:hover { transform: translateY(-3px); }
.btn.ghost { border-color: var(--line-2); color: var(--ink); }
.btn.ghost:hover { background: rgba(255,255,255,0.05); transform: translateY(-3px); }
.hero-stats { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; max-width: 780px;
  border-top: 1px solid var(--line); padding-top: 26px; }
.hero-stats b { font-family: var(--mono); font-weight: 600; font-size: clamp(26px,4vw,42px); color: var(--amber); display: block; }
.hero-stats span { font-size: 12.5px; color: var(--ink-faint); }
@media (max-width: 620px) { .hero-stats { grid-template-columns: 1fr; gap: 14px; } }

/* Sections */
.section { max-width: var(--maxw); margin: 0 auto; padding: clamp(70px,11vw,130px) clamp(20px,5vw,52px); }
.section.alt { max-width: none; background: linear-gradient(to bottom, transparent, rgba(17,19,28,0.6), transparent); }
.section.alt > * { max-width: var(--maxw); margin-left: auto; margin-right: auto; }
.section-head { max-width: 760px; margin-bottom: 50px; }
.eyebrow { font-family: var(--mono); font-size: 12px; letter-spacing: 0.2em; color: var(--amber); text-transform: uppercase; margin-bottom: 16px; }
.section-head h2 { font-weight: 600; font-size: clamp(28px,4.6vw,48px); line-height: 1.08; letter-spacing: -0.02em; margin-bottom: 18px; }
.lede { font-size: clamp(15px,1.9vw,18px); color: var(--ink-dim); }
.lede em { color: var(--amber); font-style: italic; }
.loading { font-family: var(--mono); color: var(--ink-faint); padding: 30px 0; }

/* Space cards */
.cards { display: grid; grid-template-columns: repeat(2,1fr); gap: 18px; }
@media (max-width: 800px) { .cards { grid-template-columns: 1fr; } }
.scard { border: 1px solid var(--line); border-radius: 15px; padding: 24px 24px 22px;
  background: linear-gradient(180deg, var(--panel), rgba(11,13,20,0.4)); }
.scard-top { display: flex; align-items: center; gap: 12px; margin-bottom: 8px; }
.scard-cn { font-family: var(--serif); font-weight: 900; font-size: 26px; color: var(--amber); }
.scard h3 { font-size: 18.5px; font-weight: 600; }
.badge { display: inline-block; font-family: var(--mono); font-size: 10.5px; letter-spacing: 0.04em;
  padding: 4px 10px; border-radius: 6px; margin-bottom: 16px; border: 1px solid var(--line-2); color: var(--ink-dim); }
.badge.b-real, .badge.b-station { border-color: rgba(52,211,153,0.45); color: var(--green); }
.badge.b-lab, .badge.b-demo, .badge.b-flight { border-color: rgba(63,227,255,0.4); color: var(--cyan); }
.badge.b-dev, .badge.b-plan, .badge.b-early, .badge.b-ground { border-color: rgba(245,166,35,0.45); color: var(--amber); }
.badge.b-spec { border-color: rgba(232,35,58,0.45); color: #ff8a96; }
.scard ul { list-style: none; display: flex; flex-direction: column; gap: 11px; margin-bottom: 16px; }
.scard li { font-size: 13.5px; color: var(--ink-dim); padding-left: 18px; position: relative; }
.scard li::before { content: "→"; position: absolute; left: 0; color: var(--amber); }
.bottom { font-size: 13.5px; color: var(--ink); border-left: 2px solid var(--amber); padding-left: 12px; }
.bottom b { color: var(--amber); font-weight: 600; }

/* Fronts */
.fronts { display: grid; grid-template-columns: repeat(2,1fr); gap: 14px; }
@media (max-width: 800px) { .fronts { grid-template-columns: 1fr; } }
.front { border: 1px solid var(--line); border-radius: 12px; padding: 18px 20px; background: var(--panel); }
.front-top { display: flex; align-items: baseline; gap: 10px; margin-bottom: 8px; flex-wrap: wrap; }
.front-top h4 { font-size: 16px; font-weight: 600; }
.front-cat { font-family: var(--mono); font-size: 10.5px; color: var(--ink-faint); }
.tier { font-family: var(--mono); font-size: 9.5px; letter-spacing: 0.08em; text-transform: uppercase; padding: 2px 7px; border-radius: 4px; margin-left: auto; }
.t-critical { background: rgba(232,35,58,0.18); color: #ff8a96; } .t-high { background: rgba(245,166,35,0.16); color: var(--amber); } .t-standard { background: rgba(63,227,255,0.14); color: var(--cyan); }
.front .wall { font-size: 13px; color: var(--ink-dim); }
.front .wall b { color: var(--ink); font-weight: 600; }

/* Constraints */
.constraints { display: flex; flex-direction: column; gap: 14px; }
.constraint { border: 1px solid var(--line); border-radius: 13px; padding: 22px 24px; background: var(--panel);
  display: grid; grid-template-columns: 200px 1fr; gap: 20px; }
@media (max-width: 700px) { .constraint { grid-template-columns: 1fr; gap: 10px; } }
.c-left h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.sev { font-family: var(--mono); font-size: 10.5px; letter-spacing: 0.06em; text-transform: uppercase; padding: 3px 9px; border-radius: 5px; display: inline-block; }
.sev-hard { background: rgba(232,35,58,0.18); color: #ff8a96; border: 1px solid rgba(232,35,58,0.4); }
.sev-structural { background: rgba(245,166,35,0.16); color: var(--amber); border: 1px solid rgba(245,166,35,0.4); }
.sev-operational, .sev-erosive { background: rgba(63,227,255,0.13); color: var(--cyan); border: 1px solid rgba(63,227,255,0.35); }
.c-right .wall { font-size: 14px; color: var(--ink); margin-bottom: 8px; }
.c-right .why { font-size: 13px; color: var(--ink-dim); }

/* Footer */
.footer { border-top: 1px solid var(--line); padding: 46px clamp(20px,5vw,52px); max-width: var(--maxw); margin: 0 auto; }
.footer-main { display: flex; gap: 16px; align-items: flex-start; margin-bottom: 20px; }
.footer-main p { font-size: 14px; } .muted { color: var(--ink-faint); } .muted a { color: var(--amber); }
.muted.small, .footer .small { font-size: 12px; } .footer-main .muted { max-width: 640px; margin-top: 4px; }