/* ── Reset & base ──────────────────────────────────────────────── */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #0a0a0f;
  --text: #ffffff;
  --accent: #ffd54f;
  --accent-dim: #ffa00066;
  --danger: #ff1744;
  --danger-glow: #ff174488;
  --gold: #ffd740;
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

html {
  position: fixed;
  inset: 0;
  overflow: hidden;
}

body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

/* ── Canvas ────────────────────────────────────────────────────── */
#canvas-container {
  position: fixed;
  inset: 0;
  z-index: 0;
}

#canvas-container canvas {
  display: block;
}

/* ── Vertex labels ─────────────────────────────────────────────── */
.vertex-label {
  position: absolute;
  z-index: 10;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  pointer-events: auto;
  cursor: pointer;
  transform: translate(-50%, -50%);
  transition: transform 0.25s ease, opacity 0.3s ease;
  -webkit-tap-highlight-color: transparent;
}

.vertex-label .label-text {
  font-size: clamp(0.85rem, 3vw, 1.1rem);
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #ffffff;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.9), 0 0 8px rgba(0, 0, 0, 0.6);
  transition: color 0.3s ease, text-shadow 0.3s ease;
}

.vertex-label .label-status {
  font-size: clamp(0.55rem, 1.8vw, 0.7rem);
  height: 1em;
  opacity: 0.6;
  transition: opacity 0.3s ease;
}

/* Selected state */
.vertex-label.selected .label-text {
  color: var(--accent);
  text-shadow: 0 0 8px var(--accent-dim);
}

.vertex-label.selected .label-status::after {
  content: '🔒 LOCKED';
  color: var(--accent);
}

/* Locked-out state (2 already selected, this is the flex one) */
.vertex-label.locked-out {
  opacity: 0.5;
}

.vertex-label.locked-out .label-status::after {
  content: '⚡ FLEXIBLE';
  color: var(--gold);
}

/* Shake animation for locked-out tap */
.vertex-label.shake {
  animation: shake 0.4s ease;
}

@keyframes shake {
  0%, 100% { transform: translate(-50%, -50%) rotate(0deg); }
  20% { transform: translate(-48%, -50%) rotate(-2deg); }
  40% { transform: translate(-52%, -50%) rotate(2deg); }
  60% { transform: translate(-49%, -50%) rotate(-1deg); }
  80% { transform: translate(-51%, -50%) rotate(1deg); }
}

/* ── Instructions banner ───────────────────────────────────────── */
#instructions {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 20;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 213, 79, 0.2);
  border-radius: 1rem;
  padding: 0.7rem 1.4rem;
  text-align: center;
  font-size: clamp(0.75rem, 2.5vw, 0.9rem);
  color: rgba(224, 224, 232, 0.7);
  max-width: 90vw;
  transition: opacity 0.5s ease;
}

#instructions strong {
  color: var(--accent);
}

/* ── Overlay base ──────────────────────────────────────────────── */
.overlay {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.overlay.hidden {
  display: none;
}

/* ── Confirmation popup ────────────────────────────────────────── */
#popup-overlay {
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

#popup {
  background: #14141f;
  border: 1px solid rgba(255, 23, 68, 0.3);
  border-radius: 1.2rem;
  padding: clamp(1.5rem, 5vw, 2.5rem);
  max-width: min(90vw, 420px);
  text-align: center;
  box-shadow: 0 0 60px rgba(255, 23, 68, 0.15);
  animation: popIn 0.3s ease;
}

@keyframes popIn {
  0% { transform: scale(0.85); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

#popup h2 {
  font-size: clamp(1.3rem, 4vw, 1.8rem);
  margin-bottom: 0.8rem;
  color: var(--danger);
}

#popup p {
  font-size: clamp(0.85rem, 2.8vw, 1rem);
  color: rgba(224, 224, 232, 0.75);
  line-height: 1.5;
  margin-bottom: 1.5rem;
}

.popup-buttons {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

@media (min-width: 480px) {
  .popup-buttons {
    flex-direction: row;
    justify-content: center;
    gap: 1rem;
  }
}

.popup-buttons button {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 0.7rem;
  font-size: clamp(0.85rem, 2.5vw, 1rem);
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.2s ease;
}

.popup-buttons button:active {
  transform: scale(0.96);
}

#popup-cancel {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

#popup-cancel:hover {
  background: rgba(255, 255, 255, 0.14);
}

#popup-confirm {
  background: var(--danger);
  color: #fff;
  box-shadow: 0 0 20px var(--danger-glow);
}

#popup-confirm:hover {
  box-shadow: 0 0 30px var(--danger-glow);
}

/* ── Failure overlay ───────────────────────────────────────────── */
#failure-overlay {
  background: rgba(0, 0, 0, 0.92);
}

#failure-overlay.visible {
  animation: screenFlash 0.6s ease;
}

@keyframes screenFlash {
  0% { background: rgba(255, 23, 68, 0.8); }
  30% { background: rgba(255, 23, 68, 0.4); }
  100% { background: rgba(0, 0, 0, 0.92); }
}

#failure-content {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  width: 80%;
  max-width: 500px;
}

#failure-text {
  font-size: 1rem;
  font-weight: 800;
  color: var(--danger);
  text-shadow: 0 0 20px var(--danger-glow), 0 0 40px var(--danger-glow);
  line-height: 1.4;
}

@media (min-width: 480px) {
  #failure-text { font-size: 1.4rem; }
}

@media (min-width: 768px) {
  #failure-text {
    font-size: 2.2rem;
    text-shadow: 0 0 40px var(--danger-glow), 0 0 80px var(--danger-glow);
  }
}

#failure-reset {
  margin-top: 1.2rem;
  padding: 0.6rem 1.4rem;
  border: 2px solid var(--danger);
  border-radius: 0.7rem;
  background: transparent;
  color: var(--danger);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, transform 0.15s ease;
}

#failure-reset:hover {
  background: var(--danger);
  color: #fff;
}

#failure-reset:active {
  transform: scale(0.96);
}

/* ── Screen shake ──────────────────────────────────────────────── */
body.screen-shake {
  animation: screenShake 0.5s ease;
}

@keyframes screenShake {
  0%, 100% { transform: translate(0, 0); }
  10% { transform: translate(-4px, 2px); }
  20% { transform: translate(4px, -2px); }
  30% { transform: translate(-3px, 3px); }
  40% { transform: translate(3px, -1px); }
  50% { transform: translate(-2px, 2px); }
  60% { transform: translate(2px, -2px); }
  70% { transform: translate(-1px, 1px); }
  80% { transform: translate(1px, -1px); }
}

/* ── Utility ───────────────────────────────────────────────────── */
.hidden {
  display: none !important;
}