:root {
  --bg-main: #080c14;
  --bg-card: #0f172a;
  --bg-panel: #111827;
  --border-dim: #1e293b;
  --border-glow: #38bdf8;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --cyan: #38bdf8;
  --cyan-glow: rgba(56, 189, 248, 0.25);
  
  /* Board Colors */
  --board-light: #cbd5e1;
  --board-dark: #334155;
  --board-highlight: rgba(56, 189, 248, 0.4);
  --board-lastmove: rgba(245, 158, 11, 0.35);

  /* Move Grades */
  --grade-brilliant: #38bdf8;
  --grade-best: #10b981;
  --grade-good: #64748b;
  --grade-inaccuracy: #f59e0b;
  --grade-mistake: #f97316;
  --grade-blunder: #ef4444;
  --grade-book: #0ea5e9;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-main);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* Header & Duel Scoreboard */
header {
  width: 100%;
  max-width: 1100px;
  padding: 1.25rem 1rem;
  border-bottom: 1px solid var(--border-dim);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-title {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.logo-tag {
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  background: var(--bg-panel);
  border: 1px solid var(--border-dim);
  color: var(--cyan);
  border-radius: 4px;
}

.score-banner {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  background: var(--bg-card);
  padding: 0.5rem 1.25rem;
  border: 1px solid var(--border-dim);
  border-radius: 8px;
}

.score-col {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.score-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  color: var(--text-dim);
  letter-spacing: 0.05em;
}

.score-val {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--cyan);
}

.score-divider {
  color: var(--border-dim);
  font-size: 1.2rem;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

button {
  background: var(--bg-card);
  border: 1px solid var(--border-dim);
  color: var(--text-main);
  padding: 0.5rem 0.9rem;
  border-radius: 6px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

button:hover {
  border-color: var(--cyan);
  background: #1e293b;
}

button.primary {
  background: var(--cyan);
  color: #080c14;
  font-weight: 600;
  border-color: var(--cyan);
}

button.primary:hover {
  background: #7dd3fc;
}

/* Arena Layout */
main {
  width: 100%;
  max-width: 1100px;
  padding: 1.5rem 1rem;
  display: grid;
  grid-template-columns: auto 340px;
  gap: 1.5rem;
  flex: 1;
}

@media (max-width: 880px) {
  main {
    grid-template-columns: 1fr;
    justify-items: center;
  }
}

/* Chessboard Area */
.board-container {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  width: min(520px, 90vw);
}

.player-strip {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--bg-card);
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  border: 1px solid var(--border-dim);
}

.player-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  font-weight: 600;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #475569;
}

.status-dot.online {
  background: var(--cyan);
  box-shadow: 0 0 8px var(--cyan);
}

.clock {
  font-family: "JetBrains Mono", monospace;
  font-size: 1.15rem;
  font-weight: 700;
  padding: 0.2rem 0.6rem;
  background: var(--bg-main);
  border: 1px solid var(--border-dim);
  border-radius: 4px;
  min-width: 72px;
  text-align: center;
}

.clock.active {
  border-color: var(--cyan);
  color: var(--cyan);
  box-shadow: 0 0 10px var(--cyan-glow);
}

#chessboard {
  width: 100%;
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  border: 2px solid var(--border-dim);
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
  user-select: none;
}

.square {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
}

.square.light { background-color: var(--board-light); }
.square.dark { background-color: var(--board-dark); }

.square.last-move {
  background-color: var(--board-lastmove) !important;
}

.square.selected {
  outline: 3px solid var(--cyan);
  outline-offset: -3px;
  z-index: 2;
}

.square.check {
  background-color: rgba(239, 68, 68, 0.45) !important;
}

.move-dot {
  width: 28%;
  height: 28%;
  background: rgba(15, 23, 42, 0.35);
  border-radius: 50%;
  pointer-events: none;
}

.piece-svg {
  width: 85%;
  height: 85%;
  pointer-events: none;
}

/* Sidebar & Tabs */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.panel {
  background: var(--bg-card);
  border: 1px solid var(--border-dim);
  border-radius: 8px;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.panel-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-dim);
  border-bottom: 1px solid var(--border-dim);
  padding-bottom: 0.5rem;
}

/* Move List */
.move-history {
  height: 200px;
  overflow-y: auto;
  font-family: "JetBrains Mono", monospace;
  font-size: 0.85rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.move-row {
  display: grid;
  grid-template-columns: 36px 1fr 1fr;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
}

.move-row:nth-child(even) {
  background: rgba(255,255,255,0.02);
}

.move-num {
  color: var(--text-dim);
}

.move-cell {
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.move-cell:hover {
  color: var(--cyan);
}

.move-cell.active {
  background: #1e293b;
  border-radius: 3px;
  padding: 0 4px;
}

/* Review Badges (No Childish Emojis) */
.badge {
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.1rem 0.35rem;
  border-radius: 3px;
  letter-spacing: 0.02em;
}

.badge-brilliant { background: #0284c7; color: #fff; }
.badge-best { background: #059669; color: #fff; }
.badge-good { background: #475569; color: #fff; }
.badge-inaccuracy { background: #d97706; color: #fff; }
.badge-mistake { background: #ea580c; color: #fff; }
.badge-blunder { background: #dc2626; color: #fff; }
.badge-book { background: #0284c7; color: #fff; }

/* Review Summary Panel */
.review-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  text-align: center;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border-dim);
}

.accuracy-score {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--cyan);
  font-family: "JetBrains Mono", monospace;
}

.accuracy-label {
  font-size: 0.75rem;
  color: var(--text-dim);
}

/* Modal */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(4px);
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 100;
}

.modal-overlay.active {
  display: flex;
}

.modal-card {
  background: var(--bg-card);
  border: 1px solid var(--border-dim);
  border-radius: 8px;
  padding: 1.5rem;
  width: min(380px, 90vw);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.modal-title {
  font-size: 1.1rem;
  font-weight: 700;
}

input[type="password"], input[type="text"] {
  background: var(--bg-main);
  border: 1px solid var(--border-dim);
  color: var(--text-main);
  padding: 0.6rem 0.8rem;
  border-radius: 6px;
  font-size: 0.9rem;
  outline: none;
}

input[type="password"]:focus, input[type="text"]:focus {
  border-color: var(--cyan);
}