:root {
  --harbor: #041428;
  --steel: #0a1c33;
  --orange: #ff6a2a;
  --orange-2: #ffb089;
  --foam: #d8e7f2;
  --mute: #7f93a6;
  --ban: #c81e1e;
  --ok: #3cb38a;
  --line: rgba(255, 106, 42, 0.28);
  --display: "Black Han Sans", "Noto Sans SC", sans-serif;
  --sans: "Noto Sans SC", "PingFang SC", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
section[id] { scroll-margin-top: 72px; }
body {
  margin: 0;
  color: var(--foam);
  background: var(--harbor);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.app-link { color: var(--orange-2); text-decoration: underline; text-underline-offset: 3px; }
button { font-family: inherit; cursor: pointer; }
code { font-family: var(--mono); background: rgba(255, 106, 42, 0.14); padding: 0.05em 0.35em; }

.spray {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 40;
  opacity: 0.13;
  background-image: url("images/texture.webp");
  background-size: 480px auto;
  mix-blend-mode: overlay;
}
.skip { position: absolute; left: -999px; }
.skip:focus { left: 12px; top: 12px; z-index: 80; background: var(--orange); color: var(--harbor); padding: 8px 12px; }

.bridge {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 24px 10px 36px;
  background: rgba(4, 20, 40, 0.94);
  border-bottom: 2px solid var(--orange);
}
.boat-mark { display: flex; align-items: center; gap: 10px; font-family: var(--display); font-size: 22px; letter-spacing: 0.04em; }
.boat-mark small { display: block; font-family: var(--mono); font-size: 10px; letter-spacing: 0.14em; color: var(--mute); font-weight: 400; }
.rung-icon {
  width: 22px;
  height: 28px;
  background:
    repeating-linear-gradient(180deg, var(--orange) 0 4px, transparent 4px 8px);
  border-left: 2px solid var(--orange-2);
  border-right: 2px solid var(--orange-2);
}
.nav-toggle { display: none; background: var(--orange); color: var(--harbor); border: 0; padding: 10px 14px; font-size: 16px; }
.bridge-links { display: flex; gap: 16px; align-items: center; font-size: 14px; }
.bridge-links a { color: var(--mute); }
.bridge-links a.is-active, .bridge-links a:hover { color: var(--orange); }
.bridge-links .live { background: var(--orange); color: var(--harbor); padding: 8px 12px; }

.ladder-rail {
  position: fixed;
  right: 18px;
  top: 80px;
  bottom: 24px;
  width: 28px;
  z-index: 30;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  border-left: 3px solid #c45a28;
  border-right: 3px solid #c45a28;
  pointer-events: none;
}
.ladder-rail b { height: 10px; background: var(--orange); }
.ladder-rail b.gone { background: var(--ban); opacity: 0.35; }

.hull { position: relative; min-height: 100vh; display: grid; align-items: end; }
.hull img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.hull::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(4, 20, 40, 0.92) 0%, rgba(4, 20, 40, 0.55) 48%, rgba(4, 20, 40, 0.2) 100%),
    linear-gradient(180deg, transparent 40%, rgba(4, 20, 40, 0.9) 100%);
}
.hull-copy { position: relative; z-index: 1; padding: 12vh 10vw 8vh 6vw; max-width: 760px; }
.kicker { font-family: var(--mono); letter-spacing: 0.16em; font-size: 12px; color: var(--orange); margin: 0 0 10px; }
h1, h2, h3 { font-family: var(--display); font-weight: 400; letter-spacing: 0.02em; margin: 0 0 12px; line-height: 1.05; }
h1 { font-size: clamp(44px, 7vw, 88px); }
h2 { font-size: clamp(28px, 4vw, 44px); }
h3 { font-size: 22px; }
.lead { font-size: 17px; }
.flags { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 20px 0; }
.flags li { font-family: var(--mono); font-size: 12px; background: rgba(255, 106, 42, 0.12); border: 1px solid var(--line); padding: 4px 10px; }
.hull-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.btn { display: inline-flex; align-items: center; padding: 12px 16px; font-size: 15px; border: 2px solid currentColor; }
.fill { background: var(--orange); color: var(--harbor); border-color: var(--orange); }
.ghost { background: transparent; color: var(--foam); }

.hold { width: min(1040px, calc(100% - 72px)); margin: 0 auto; padding: 72px 0; }
.deck { background: var(--steel); }
.invert { background: var(--harbor); }
.deck-lead { color: var(--mute); max-width: 44em; }

.rung-stack { display: flex; flex-direction: column; gap: 0; margin-top: 28px; border-left: 6px solid var(--orange); }
.rung { padding: 20px 22px; border-bottom: 10px solid var(--harbor); background: #10263f; }
.rung span { font-family: var(--mono); font-size: 11px; letter-spacing: 0.14em; color: var(--orange); }
.warn-rung { border-left: 8px solid var(--ban); }
.rung ul { margin: 8px 0 0; padding-left: 1.1em; }

.step-rung { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; align-items: center; margin: 48px 0; }
.step-rung.reverse figure { order: 2; }
.step-id { font-family: var(--mono); color: var(--orange); letter-spacing: 0.12em; font-size: 12px; display: block; margin-bottom: 8px; }
figure { margin: 0; }
figure img { width: 100%; height: 280px; object-fit: cover; border-top: 8px solid var(--orange); }
figcaption { margin-top: 8px; font-size: 13px; color: var(--mute); }

.gauge, .ladder-check { margin-top: 16px; padding: 14px; background: #07182c; border: 2px solid var(--orange); }
.gauge-label { margin: 0 0 10px; font-family: var(--mono); font-size: 12px; color: var(--mute); }
.gauge-row { display: grid; grid-template-columns: 40px 1fr 72px; gap: 10px; align-items: center; }
.gauge-row input { width: 100%; accent-color: var(--orange); }
.gauge-row strong { font-family: var(--mono); color: var(--orange); font-size: 18px; }
.wave-state { margin: 10px 0 0; font-family: var(--mono); font-size: 14px; }
.wave-state.ok { color: var(--ok); }
.wave-state.warn { color: var(--ban); }
.ladder-check label { display: flex; gap: 10px; align-items: center; font-size: 15px; }
.ladder-check input { width: 20px; height: 20px; accent-color: var(--ban); }

.module-rungs { list-style: none; margin: 28px 0 0; padding: 0; display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; }
.module-rungs li { background: #10263f; padding: 18px; border-top: 10px solid var(--orange); }
.module-rungs li:nth-child(even) { border-top-color: var(--ban); }
.module-rungs p { margin: 0; color: var(--mute); font-size: 14px; }

.value-rungs { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 24px; }
.value-rungs article { padding: 18px; background: #10263f; box-shadow: inset 8px 0 0 var(--orange); }
.value-rungs p { margin: 0; color: var(--mute); }

.ban-list { max-width: 46em; font-size: 17px; }
.ban-list li { margin: 0.55em 0; }

.io { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; margin-top: 20px; }
.io ul { margin: 0; padding-left: 1.1em; }

footer { background: #020b16; border-top: 2px solid var(--orange); color: var(--mute); }
.foot { display: flex; justify-content: space-between; gap: 12px; font-size: 13px; padding-top: 24px; padding-bottom: 24px; }

@media (max-width: 860px) {
  .ladder-rail { display: none; }
  .nav-toggle { display: block; }
  .bridge-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    padding: 12px 16px 18px;
    background: var(--harbor);
  }
  .bridge-links.open { display: flex; }
  .hold { width: min(1040px, calc(100% - 28px)); padding: 48px 0; }
  .step-rung, .step-rung.reverse, .module-rungs, .value-rungs, .io, .foot { grid-template-columns: 1fr; display: grid; }
  .step-rung.reverse figure { order: 0; }
  h1 { font-size: 40px; }
  figure img { height: 200px; }
  .gauge-row { grid-template-columns: 1fr; }
  .btn { min-height: 44px; }
  .hull::after { background: linear-gradient(180deg, rgba(4,20,40,0.35) 0%, rgba(4,20,40,0.92) 100%); }
}