/* ============================================================
   HUD — persistent chrome above the field
   ============================================================ */

.hud {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 100;
}
.hud > * { pointer-events: auto; }

/* ---------- Top rail: beacon (L) + nav (R) ---------- */
.top-rail {
  position: fixed;
  top: 0; inset-inline: 0;
  height: var(--nav-h);
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 101;
  pointer-events: none;
}
.top-rail > * { pointer-events: auto; }

/* Beacon */
.beacon {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px 10px 12px;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-edge);
  border-radius: 14px;
  color: var(--foam);
  font-family: 'JetBrains Mono', monospace;
  font-size: var(--t-12);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform var(--dur-ui) var(--ease-out), border-color var(--dur-ui) var(--ease-out);
}
.beacon:hover { border-color: var(--glass-edge-2); }
.beacon:active { transform: scale(0.97); transition-duration: 160ms; }
.beacon-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--biolume);
  box-shadow: 0 0 12px var(--biolume), 0 0 24px color-mix(in oklab, var(--biolume) 40%, transparent);
  animation: beacon-pulse 2.4s var(--ease-in-out) infinite;
}
@keyframes beacon-pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(0.85); }
}
.beacon-num { color: var(--biolume); }
.beacon-name { color: var(--foam); }
.beacon-sep { color: var(--mist-dim); }

/* Nav */
.nav {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-edge);
  border-radius: 14px;
}
.nav a, .nav button {
  appearance: none;
  border: none;
  background: transparent;
  color: var(--mist);
  font: inherit;
  font-family: 'JetBrains Mono', monospace;
  font-size: var(--t-12);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 8px 12px;
  border-radius: 9px;
  cursor: pointer;
  text-decoration: none;
  transition: color var(--dur-ui) var(--ease-out), background var(--dur-ui) var(--ease-out);
}
.nav a:hover, .nav button:hover { color: var(--foam); background: var(--glass-bg-2); }
.nav a:active, .nav button:active { transform: scale(0.97); transition-duration: 160ms; }
.nav .lang {
  color: var(--biolume);
  border-inline-start: 1px solid var(--glass-edge);
  border-radius: 0 9px 9px 0;
  margin-inline-start: 4px;
  padding-inline-start: 14px;
}
html[dir="rtl"] .nav .lang {
  border-radius: 9px 0 0 9px;
}

/* ---------- Depth meter (right in EN, left in FA via logical) ---------- */
.depth-meter {
  position: fixed;
  top: 50%;
  inset-inline-end: 20px;
  transform: translateY(-50%);
  width: 74px;
  height: min(64vh, 520px);
  padding: 16px 10px;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-edge);
  border-radius: 20px;
  z-index: 101;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}
.depth-meter .depth-head {
  font-family: 'JetBrains Mono', monospace;
  font-size: 9px;
  letter-spacing: 0.24em;
  color: var(--mist-dim);
  text-transform: uppercase;
}
.depth-meter .depth-value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 18px;
  font-weight: 500;
  color: var(--foam);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}
.depth-meter .depth-unit {
  font-family: 'JetBrains Mono', monospace;
  font-size: 9px;
  color: var(--mist-dim);
  letter-spacing: 0.2em;
  margin-top: -6px;
}
.depth-rail {
  position: relative;
  flex: 1;
  width: 2px;
  background: linear-gradient(to bottom, transparent, var(--glass-edge) 10%, var(--glass-edge) 90%, transparent);
  border-radius: 2px;
}
.depth-fill {
  position: absolute;
  top: 0; left: -1px;
  width: 4px;
  height: calc(var(--scroll-depth) * 100%);
  background: linear-gradient(
    to bottom,
    var(--biolume),
    var(--biolume-deep) 60%,
    var(--biolume-dim)
  );
  border-radius: 2px;
  box-shadow: 0 0 10px color-mix(in oklab, var(--biolume) 60%, transparent);
  transition: none;
}
.depth-cursor {
  position: absolute;
  left: -6px;
  top: calc(var(--scroll-depth) * 100%);
  width: 14px;
  height: 14px;
  transform: translateY(-50%);
}
.depth-cursor::before {
  content: '';
  position: absolute;
  inset: 3px;
  border-radius: 50%;
  background: var(--foam);
  box-shadow: 0 0 8px var(--biolume);
}
.depth-cursor::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 1px solid var(--biolume);
  animation: cursor-ping 2s var(--ease-out) infinite;
}
@keyframes cursor-ping {
  0% { transform: scale(1); opacity: 1; }
  100% { transform: scale(2.2); opacity: 0; }
}
.depth-ticks {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.depth-tick {
  position: absolute;
  left: -10px;
  width: 8px;
  height: 1px;
  background: var(--mist-dim);
}
.depth-tick.crossed { background: var(--biolume); box-shadow: 0 0 6px var(--biolume); }
.depth-tick-label {
  position: absolute;
  inset-inline-end: 12px;
  transform: translateY(-50%);
  font-family: 'JetBrains Mono', monospace;
  font-size: 9px;
  color: var(--mist-dim);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  white-space: nowrap;
  opacity: 0;
  transition: opacity var(--dur-ui) var(--ease-out);
}
.depth-tick:hover .depth-tick-label,
.depth-tick.crossed .depth-tick-label { opacity: 0.7; }

/* Signal strength */
.signal-strength {
  display: inline-flex;
  align-items: flex-end;
  gap: 2px;
  height: 14px;
  margin-top: 2px;
}
.signal-strength .bar {
  width: 3px;
  background: var(--mist-dim);
  border-radius: 1px;
  transition: background var(--dur-ui) var(--ease-out), height var(--dur-scene) var(--ease-out);
}
.signal-strength .bar:nth-child(1) { height: 4px; }
.signal-strength .bar:nth-child(2) { height: 7px; }
.signal-strength .bar:nth-child(3) { height: 10px; }
.signal-strength .bar:nth-child(4) { height: 13px; }
.signal-strength .bar.on { background: var(--biolume); box-shadow: 0 0 4px var(--biolume); }
.signal-strength .bar.full { background: var(--signal); box-shadow: 0 0 6px var(--signal); }

.signal-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 8px;
  letter-spacing: 0.24em;
  color: var(--mist-dim);
  text-transform: uppercase;
}

/* ---------- Custom sonar cursor ---------- */
@media (hover: hover) and (pointer: fine) {
  html.cursor-on, html.cursor-on * { cursor: none !important; }
  .cursor {
    position: fixed;
    top: 0; left: 0;
    width: 20px; height: 20px;
    pointer-events: none;
    z-index: 9999;
    transform: translate(-50%, -50%);
    mix-blend-mode: normal;
    will-change: transform;
  }
  .cursor-dot {
    position: absolute;
    inset: 6px;
    background: var(--biolume);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--biolume);
  }
  .cursor-ring {
    position: absolute;
    inset: 0;
    border: 1px solid var(--biolume);
    border-radius: 50%;
    opacity: 0.6;
    transition: transform var(--dur-ui) var(--ease-out), inset var(--dur-ui) var(--ease-out), border-color var(--dur-ui) var(--ease-out), opacity var(--dur-ui) var(--ease-out);
  }
  .cursor.lock .cursor-ring {
    inset: -12px;
    border-color: var(--signal);
    opacity: 1;
    /* brackets */
    background:
      linear-gradient(var(--signal), var(--signal)) top left / 8px 1px no-repeat,
      linear-gradient(var(--signal), var(--signal)) top left / 1px 8px no-repeat,
      linear-gradient(var(--signal), var(--signal)) top right / 8px 1px no-repeat,
      linear-gradient(var(--signal), var(--signal)) top right / 1px 8px no-repeat,
      linear-gradient(var(--signal), var(--signal)) bottom left / 8px 1px no-repeat,
      linear-gradient(var(--signal), var(--signal)) bottom left / 1px 8px no-repeat,
      linear-gradient(var(--signal), var(--signal)) bottom right / 8px 1px no-repeat,
      linear-gradient(var(--signal), var(--signal)) bottom right / 1px 8px no-repeat;
    border: none;
    border-radius: 4px;
  }
  .cursor.lock .cursor-dot { background: var(--signal); box-shadow: 0 0 6px var(--signal); }
  .cursor-label {
    position: absolute;
    top: 24px; left: 24px;
    padding: 3px 8px;
    background: var(--signal);
    color: var(--abyss);
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    border-radius: 4px;
    opacity: 0;
    transform: translate(-4px, -4px);
    transition: opacity var(--dur-ui) var(--ease-out), transform var(--dur-ui) var(--ease-out);
    white-space: nowrap;
  }
  .cursor.lock .cursor-label { opacity: 1; transform: translate(0, 0); }
  .cursor-ping {
    position: absolute;
    top: 50%; left: 50%;
    width: 20px; height: 20px;
    border: 1.5px solid var(--biolume);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
    animation: cursor-click-ping 900ms var(--ease-out) forwards;
  }
  @keyframes cursor-click-ping {
    0% { width: 20px; height: 20px; opacity: 0.8; }
    100% { width: 120px; height: 120px; opacity: 0; }
  }
}
@media (pointer: coarse), (hover: none) {
  .cursor { display: none !important; }
}

/* ---------- Act index overlay ---------- */
.act-index {
  position: fixed;
  inset: 0;
  background: rgb(4 7 14 / 0.86);
  backdrop-filter: blur(24px);
  z-index: 300;
  display: grid;
  place-items: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-scene) var(--ease-drawer);
}
.act-index.open {
  opacity: 1;
  pointer-events: auto;
}
.act-index-inner {
  width: min(680px, 88vw);
  transform: translateY(24px);
  transition: transform var(--dur-scene) var(--ease-drawer);
}
.act-index.open .act-index-inner { transform: translateY(0); }
.act-index h2 {
  font-size: var(--t-14);
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: 0.24em;
  color: var(--mist);
  text-transform: uppercase;
  margin: 0 0 20px;
  font-weight: 400;
}
.act-list {
  list-style: none;
  padding: 0; margin: 0;
  border-top: 1px solid var(--glass-edge);
}
.act-list li { border-bottom: 1px solid var(--glass-edge); }
.act-list button {
  width: 100%;
  appearance: none;
  border: none;
  background: transparent;
  padding: 22px 4px;
  display: flex;
  align-items: baseline;
  gap: 24px;
  color: var(--foam);
  text-align: start;
  cursor: pointer;
  font-family: inherit;
  transition: padding var(--dur-ui) var(--ease-out), color var(--dur-ui) var(--ease-out);
}
.act-list button:hover { padding-inline-start: 16px; color: var(--biolume); }
.act-list .num {
  font-family: 'JetBrains Mono', monospace;
  font-size: var(--t-14);
  color: var(--mist-dim);
  min-width: 40px;
}
.act-list .name {
  font-family: 'Space Grotesk', sans-serif;
  font-size: var(--t-28);
  font-weight: 500;
  letter-spacing: -0.01em;
}
html[lang="fa"] .act-list .name { font-family: 'Vazirmatn', sans-serif; letter-spacing: 0; }
.act-list .depth {
  margin-inline-start: auto;
  font-family: 'JetBrains Mono', monospace;
  font-size: var(--t-12);
  color: var(--mist);
  letter-spacing: 0.14em;
}
.act-index-hint {
  margin-top: 20px;
  font-family: 'JetBrains Mono', monospace;
  font-size: var(--t-12);
  color: var(--mist-dim);
  letter-spacing: 0.14em;
  text-transform: uppercase;
}
.act-index-hint kbd {
  padding: 2px 6px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-edge);
  border-radius: 4px;
  font-family: inherit;
  color: var(--foam);
}

/* Mobile: hide depth meter, keep beacon + nav */
@media (max-width: 720px) {
  .depth-meter { display: none; }
  .top-rail { padding-inline: 16px; height: 56px; }
  .beacon { padding: 8px 10px; font-size: 10px; }
  .beacon-name { display: none; }
  .nav a, .nav button { padding: 6px 8px; font-size: 10px; }
}