/* Signal Bastion - responsive dark theme, accessibility-first */
:root {
  --bg: #0a0e16;
  --bg-2: #111827;
  --panel: #131a2a;
  --panel-2: #1a2236;
  --line: #283248;
  --text: #e6ecf5;
  --text-dim: #9aa7bd;
  --accent: #58e0c8;
  --accent-2: #5b8cff;
  --warn: #ff7e6b;
  --good: #79f29c;
  --bad: #ff5c7c;
  --gold: #f3c969;
  --shadow: 0 6px 18px rgba(0,0,0,0.45);
  --radius: 10px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f4f6fb; --bg-2: #e7ecf4; --panel: #ffffff; --panel-2: #f0f3f9;
    --line: #d6dde8; --text: #1c2230; --text-dim: #5a6679;
    --shadow: 0 4px 12px rgba(20,30,60,0.10);
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.35;
  display: grid;
  grid-template-rows: auto 1fr auto;
  min-height: 100dvh;
  overscroll-behavior: none;
}

.topbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 12px;
  background: var(--bg-2);
  border-bottom: 1px solid var(--line);
  gap: 8px;
}
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; }
.brand-mark {
  width: 18px; height: 18px; border-radius: 4px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: 0 0 0 2px rgba(88,224,200,0.25);
}
.brand-name { letter-spacing: 0.5px; }
.hud { display: flex; gap: 12px; flex-wrap: wrap; }
.hud-item { font-variant-numeric: tabular-nums; color: var(--text-dim); }
.hud-item span { color: var(--text); margin-left: 2px; }
.topbar-actions { display: flex; gap: 6px; }

/* Layout */
.stage {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 280px;
  min-height: 0;
}
#canvas {
  width: 100%;
  height: 100%;
  display: block;
  background:
    radial-gradient(ellipse at 20% 10%, rgba(91,140,255,0.06), transparent 60%),
    radial-gradient(ellipse at 80% 90%, rgba(88,224,200,0.06), transparent 60%),
    var(--bg);
  outline: none;
  touch-action: none;
}
.sidebar {
  background: var(--bg-2);
  border-left: 1px solid var(--line);
  padding: 10px;
  overflow-y: auto;
  display: flex; flex-direction: column; gap: 10px;
  min-height: 0;
}
.panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
}
.panel h2 { margin: 0 0 8px; font-size: 13px; text-transform: uppercase; letter-spacing: 1px; color: var(--text-dim); }

/* Tower picker */
.tower-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 6px; }
.tower-card {
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px;
  cursor: pointer;
  display: flex; flex-direction: column; gap: 4px;
  position: relative;
  text-align: left;
  color: var(--text);
  font: inherit;
}
.tower-card:hover { border-color: var(--accent); }
.tower-card.selected { outline: 2px solid var(--accent); }
.tower-card .name { font-weight: 700; display: flex; align-items: center; gap: 6px; }
.tower-card .glyph {
  width: 18px; height: 18px; border-radius: 4px;
  display: inline-block;
}
.tower-card .meta { color: var(--text-dim); font-size: 12px; }
.tower-card .cost { color: var(--gold); font-weight: 700; }
.tower-card.disabled { opacity: 0.45; cursor: not-allowed; }

.tower-detail .name { font-weight: 700; font-size: 15px; display:flex; align-items:center; gap:6px; }
.tower-detail .row { display:flex; justify-content:space-between; gap:8px; margin: 2px 0; }
.tower-detail .row .label { color: var(--text-dim); }
.tower-detail .stat-delta.up { color: var(--good); }
.tower-detail .stat-delta.down { color: var(--bad); }
.tower-detail .actions { display: flex; flex-direction: column; gap: 6px; margin-top: 8px; }
.tower-detail .upgrade-row { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.tower-detail .specializations { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.tower-detail .spec-btn, .tower-detail .upgrade-btn {
  font: inherit;
  padding: 6px 8px;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
  text-align: left;
}
.tower-detail .spec-btn:hover, .tower-detail .upgrade-btn:hover { border-color: var(--accent); }
.tower-detail .spec-btn.picked, .tower-detail .upgrade-btn.picked { border-color: var(--accent); background: rgba(88,224,200,0.08); }
.tower-detail .sell-btn {
  background: rgba(255,92,124,0.12);
  border-color: rgba(255,92,124,0.4);
  color: var(--bad);
  padding: 6px 8px;
  border-radius: 6px;
  border-width: 1px;
  border-style: solid;
  cursor: pointer;
}

/* Footer */
.footer {
  display: flex; gap: 8px; align-items: center;
  padding: 8px 12px;
  background: var(--bg-2);
  border-top: 1px solid var(--line);
}
.wave-info { margin-left: auto; color: var(--text-dim); }

.btn {
  font: inherit;
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px 12px;
  cursor: pointer;
  transition: transform 60ms ease, background 120ms ease;
}
.btn:hover { background: var(--panel); }
.btn:active { transform: translateY(1px); }
.btn[disabled] { opacity: 0.4; cursor: not-allowed; }
.btn.primary { background: linear-gradient(180deg, var(--accent), #3fbca6); color: #06231d; border-color: transparent; font-weight: 700; }
.btn.ghost { background: transparent; }
.btn.danger { background: rgba(255,92,124,0.15); border-color: rgba(255,92,124,0.4); color: var(--bad); }
.btn[aria-pressed="true"] { outline: 2px solid var(--accent); }

/* Tooltip */
.tooltip {
  position: fixed;
  z-index: 1000;
  pointer-events: none;
  max-width: 280px;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px 10px;
  box-shadow: var(--shadow);
  font-size: 12px;
}
.tooltip h3 { margin: 0 0 4px; font-size: 13px; }
.tooltip .row { display:flex; justify-content:space-between; gap: 8px; }
.tooltip .row .label { color: var(--text-dim); }
.tooltip .delta-up { color: var(--good); }
.tooltip .delta-down { color: var(--bad); }
.tooltip .swatch {
  display: inline-block; width: 10px; height: 10px; border-radius: 2px;
  margin-right: 4px; vertical-align: middle;
  border: 1px solid rgba(255,255,255,0.2);
}

/* Modal */
.modal {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.6);
  display: flex; align-items: center; justify-content: center;
  z-index: 2000;
}
.modal.hidden { display: none; }
.modal-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 18px;
  max-width: 480px;
  width: min(92vw, 480px);
  box-shadow: var(--shadow);
}
.modal-card h2 { margin: 0 0 8px; }
.modal-actions { display: flex; gap: 8px; margin-top: 12px; justify-content: flex-end; flex-wrap: wrap; }
.modal .map-list { display: grid; gap: 6px; margin: 8px 0; }
.modal .map-card {
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px;
  cursor: pointer;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4px;
}
.modal .map-card:hover { border-color: var(--accent); }
.modal .map-card.locked { opacity: 0.5; cursor: not-allowed; }
.modal .map-card .best { color: var(--gold); font-variant-numeric: tabular-nums; }

/* Visually hidden helper */
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); border: 0;
}

/* High-contrast mode */
@media (prefers-contrast: more) {
  :root { --line: #ffffff; }
}

/* Reduced motion: kill ambient animation, keep gameplay visibility cues */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* Mobile / narrow */
@media (max-width: 720px) {
  .stage { grid-template-columns: 1fr; grid-template-rows: 1fr 220px; }
  .sidebar { border-left: none; border-top: 1px solid var(--line); }
  .hud { font-size: 12px; gap: 8px; }
  .tower-grid { grid-template-columns: repeat(3, 1fr); }
  .topbar { padding: 6px 8px; }
}
@media (max-width: 420px) {
  .hud-item:nth-child(4) { display: none; } /* hide score on tiny screens */
  .tower-grid { grid-template-columns: repeat(2, 1fr); }
}