:root {
  --bg-dark: #070b14;
  --bg-card: rgba(14, 23, 42, 0.75);
  --panel-bg: rgba(13, 20, 36, 0.85);
  --panel-border: rgba(255, 255, 255, 0.08);
  --panel-border-glow: rgba(0, 242, 254, 0.3);
  --text: #f1f5f9;
  --muted: #94a3b8;
  --cyan: #00f2fe;
  --cyan-glow: rgba(0, 242, 254, 0.35);
  --violet: #a855f7;
  --violet-glow: rgba(168, 85, 247, 0.35);
  --emerald: #10b981;
  --emerald-glow: rgba(16, 185, 129, 0.35);
  --ruby: #f43f5e;
  --ruby-glow: rgba(244, 63, 94, 0.35);
  --gold: #fbbf24;

  /* Board Themes Default (Hoàng Gia Gỗ Tự Nhiên) */
  --sq-light: #f0d9b5;
  --sq-dark: #b58863;
  --sq-highlight: rgba(20, 184, 166, 0.65);
  --sq-lastmove: rgba(245, 158, 11, 0.45);
  --sq-check: rgba(239, 68, 68, 0.85);
  --board-border-thickness: 28px;
  --coord-border-color: #f3dfc1;
  --board-inlay-border: rgba(212, 175, 55, 0.45);
  --board-frame-gradient: linear-gradient(145deg, #2e180e 0%, #190c06 60%, #0d0603 100%);
  --board-gold-hairline: rgba(212, 175, 55, 0.5);
}

/* Board Theme: Hoàng Gia Gỗ */
body[data-board-theme="wood"] {
  --sq-light: #f0d9b5;
  --sq-dark: #b58863;
  --sq-highlight: rgba(20, 184, 166, 0.65);
  --sq-lastmove: rgba(245, 158, 11, 0.45);
  --sq-check: rgba(239, 68, 68, 0.85);
  --coord-border-color: #f3dfc1;
  --board-inlay-border: rgba(212, 175, 55, 0.45);
  --board-frame-gradient: linear-gradient(145deg, #2e180e 0%, #190c06 60%, #0d0603 100%);
  --board-gold-hairline: rgba(212, 175, 55, 0.5);
}

/* Board Theme: Tournament Xanh (Chess.com Green Championship) */
body[data-board-theme="tournament"] {
  --sq-light: #eeeed2;
  --sq-dark: #769656;
  --sq-highlight: rgba(14, 165, 233, 0.65);
  --sq-lastmove: rgba(245, 158, 11, 0.45);
  --sq-check: rgba(239, 68, 68, 0.85);
  --coord-border-color: #ecfccb;
  --board-inlay-border: rgba(163, 230, 53, 0.45);
  --board-frame-gradient: linear-gradient(145deg, #1c2e18 0%, #0e1a0b 60%, #050a04 100%);
  --board-gold-hairline: rgba(163, 230, 53, 0.45);
}

/* Board Theme: Obsidian Đêm (Sleek High-Contrast Slate) */
body[data-board-theme="obsidian"] {
  --sq-light: #cbd5e1;
  --sq-dark: #475569;
  --sq-highlight: rgba(0, 242, 254, 0.55);
  --sq-lastmove: rgba(251, 191, 36, 0.45);
  --sq-check: rgba(244, 63, 94, 0.85);
  --coord-border-color: #7dd3fc;
  --board-inlay-border: rgba(0, 242, 254, 0.45);
  --board-frame-gradient: linear-gradient(145deg, #1e293b 0%, #0f172a 60%, #050811 100%);
  --board-gold-hairline: rgba(0, 242, 254, 0.45);
}

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

body {
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-dark);
  color: var(--text);
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  line-height: 1.5;
}

/* Background animated mesh */
.background-mesh {
  position: fixed;
  inset: 0;
  background:
    radial-gradient(circle at 15% 20%, rgba(168, 85, 247, 0.12) 0%, transparent 45%),
    radial-gradient(circle at 85% 80%, rgba(0, 242, 254, 0.1) 0%, transparent 45%),
    radial-gradient(circle at 50% 50%, rgba(8, 14, 28, 0.95) 0%, #050811 100%);
  z-index: -1;
  pointer-events: none;
}

.app {
  max-width: 1400px;
  margin: 0 auto;
  padding: 12px 16px 28px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ================= HEADER ================= */
.top-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background: rgba(15, 23, 42, 0.7);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  border-radius: 16px;
  margin-bottom: 16px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.35);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}

.logo-mark {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: linear-gradient(135deg, rgba(168, 85, 247, 0.2), rgba(0, 242, 254, 0.2));
  border: 1.5px solid rgba(168, 85, 247, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 16px var(--violet-glow);
}

.brand-text h1 {
  font-size: 18px;
  font-weight: 900;
  color: #fff;
  letter-spacing: -0.01em;
  display: flex;
  align-items: center;
  gap: 8px;
}

.brand-badge {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  color: var(--muted);
  font-weight: 600;
}

.live-dot {
  width: 6px;
  height: 6px;
  background: var(--emerald);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--emerald);
  animation: pulseBeacon 1.5s infinite;
}

@keyframes pulseBeacon {
  0% { transform: scale(0.9); opacity: 0.7; }
  50% { transform: scale(1.4); opacity: 1; }
  100% { transform: scale(0.9); opacity: 0.7; }
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header-btn {
  background: rgba(22, 34, 58, 0.75);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: #fff;
  padding: 8px 14px;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.header-btn:hover {
  background: rgba(30, 48, 80, 0.95);
  border-color: var(--cyan);
  color: #fff;
}

.header-btn.icon-only {
  padding: 8px 12px;
  font-size: 14px;
}

/* ================= 3-COLUMN LAYOUT ================= */
.layout-three-cols {
  display: grid;
  grid-template-columns: 310px 1fr 310px;
  gap: 16px;
  align-items: start;
}

.col-panel {
  background: var(--panel-bg);
  backdrop-filter: blur(14px);
  border: 1px solid var(--panel-border);
  border-radius: 18px;
  overflow: hidden;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.4);
}

.panel-inner {
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* Section titles */
.sec-title {
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--cyan);
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 10px;
}

/* ================= TAB BUTTONS ================= */
.tab-row {
  display: flex;
  background: rgba(7, 11, 20, 0.6);
  padding: 4px;
  border-radius: 12px;
  gap: 4px;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.tab-btn {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--muted);
  padding: 8px 10px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s ease;
}

.tab-btn.active {
  background: rgba(0, 242, 254, 0.15);
  color: var(--cyan);
  border: 1px solid rgba(0, 242, 254, 0.3);
  box-shadow: 0 0 10px rgba(0, 242, 254, 0.2);
}

/* Input Fields */
.input-label {
  font-size: 11.5px;
  font-weight: 700;
  color: #cbd5e1;
  margin-bottom: 4px;
  display: block;
}

.custom-input {
  width: 100%;
  background: rgba(7, 11, 20, 0.9);
  border: 1.5px solid rgba(255, 255, 255, 0.12);
  border-radius: 10px;
  padding: 9px 12px;
  color: #fff;
  font-size: 13px;
  font-weight: 600;
  outline: none;
  transition: all 0.2s ease;
}

.custom-input:focus {
  border-color: var(--cyan);
  box-shadow: 0 0 12px var(--cyan-glow);
}

.custom-input.code-input {
  font-family: 'JetBrains Mono', monospace;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* Time selector buttons */
.time-selector-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

.time-btn {
  background: rgba(15, 23, 42, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: var(--muted);
  padding: 7px 4px;
  border-radius: 8px;
  font-size: 11px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: center;
}

.time-btn:hover {
  border-color: rgba(255, 255, 255, 0.2);
  color: #fff;
}

.time-btn.active {
  background: rgba(168, 85, 247, 0.18);
  color: #d8b4fe;
  border-color: rgba(168, 85, 247, 0.4);
  box-shadow: 0 0 10px var(--violet-glow);
}

/* Primary Action Buttons */
.btn-primary {
  width: 100%;
  background: linear-gradient(135deg, #00f2fe 0%, #0284c7 100%);
  color: #031120;
  border: none;
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 800;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow: 0 4px 14px var(--cyan-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 8px 22px rgba(0, 242, 254, 0.55);
}

.btn-secondary {
  width: 100%;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  color: #fff;
  padding: 8px 12px;
  border-radius: 10px;
  font-size: 12.5px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.btn-secondary:hover:not(:disabled) {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.25);
}

.btn-danger {
  background: rgba(244, 63, 94, 0.15);
  border: 1px solid rgba(244, 63, 94, 0.35);
  color: #fb7185;
}

.btn-danger:hover:not(:disabled) {
  background: rgba(244, 63, 94, 0.25);
  border-color: #f43f5e;
}

/* Room Connected Box */
.room-connected-box {
  background: rgba(8, 14, 28, 0.85);
  border: 1px solid rgba(0, 242, 254, 0.25);
  border-radius: 14px;
  padding: 14px 12px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* Big Room Code Hero Pill */
.room-code-hero-box {
  text-align: center;
  background: rgba(7, 11, 20, 0.7);
  border: 1.5px dashed rgba(0, 242, 254, 0.4);
  border-radius: 12px;
  padding: 10px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.room-code-hero-box:hover {
  background: rgba(0, 242, 254, 0.08);
  border-color: var(--cyan);
}

.code-intro {
  font-size: 11px;
  font-weight: 800;
  color: var(--muted);
  letter-spacing: 0.05em;
}

.room-code-hero-val {
  font-family: 'JetBrains Mono', monospace;
  font-size: 24px;
  font-weight: 900;
  color: var(--cyan);
  letter-spacing: 0.15em;
  margin: 3px 0;
  text-shadow: 0 0 12px var(--cyan-glow);
}

.code-hint {
  font-size: 10.5px;
  color: var(--muted);
}

/* Explicit Invite Link Block */
.invite-link-block {
  background: rgba(15, 23, 42, 0.8);
  border: 1px solid rgba(0, 242, 254, 0.25);
  border-radius: 12px;
  padding: 10px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.invite-header-label {
  font-size: 11px;
  font-weight: 800;
  color: var(--cyan);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.invite-input-row {
  display: flex;
  gap: 6px;
}

.link-input {
  font-size: 11.5px;
  font-family: 'JetBrains Mono', monospace;
  color: #94a3b8;
  background: rgba(7, 11, 20, 0.95);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  padding: 7px 10px;
  flex: 1;
  text-overflow: ellipsis;
  outline: none;
  cursor: text;
}

.link-input:focus {
  color: #fff;
  border-color: var(--cyan);
}

.btn-copy-link {
  background: linear-gradient(135deg, #00f2fe, #0284c7);
  color: #04101e;
  border: none;
  border-radius: 8px;
  padding: 0 12px;
  font-size: 12px;
  font-weight: 800;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s ease;
}

.btn-copy-link:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 14px var(--cyan-glow);
}

.btn-copy-link.copied {
  background: #10b981;
  color: #fff;
}

.host-waiting-alert {
  font-size: 11.5px;
  font-weight: 700;
  color: var(--gold);
  background: rgba(251, 191, 36, 0.1);
  border: 1px solid rgba(251, 191, 36, 0.25);
  border-radius: 8px;
  padding: 7px 10px;
  text-align: center;
  line-height: 1.45;
}

.scoreboard-box {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  background: rgba(15, 23, 42, 0.6);
  border-radius: 10px;
  padding: 8px;
  text-align: center;
}

.score-player {
  font-size: 11.5px;
  font-weight: 700;
  color: #cbd5e1;
}

.score-val {
  font-family: 'JetBrains Mono', monospace;
  font-size: 18px;
  font-weight: 900;
  color: #fff;
  padding: 0 8px;
}

/* In-game action button row */
.in-game-actions-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}

/* ================= COLUMN 2: CHESSBOARD ================= */
.col-board-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

/* Player strips (Top & Bottom) */
.player-strip {
  width: 100%;
  max-width: 580px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 14px;
  background: rgba(14, 23, 42, 0.75);
  backdrop-filter: blur(12px);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
}

.player-strip.active-turn {
  border-color: rgba(0, 242, 254, 0.5);
  box-shadow: 0 0 16px var(--cyan-glow);
}

.player-meta {
  display: flex;
  align-items: center;
  gap: 10px;
}

.player-avatar {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  border: 1.5px solid rgba(255, 255, 255, 0.1);
}

.player-avatar.white-side {
  background: #f8fafc;
  color: #0f172a;
}

.player-avatar.black-side {
  background: #0f172a;
  color: #f8fafc;
  border-color: rgba(255, 255, 255, 0.2);
}

.player-name-text {
  font-size: 13.5px;
  font-weight: 800;
  color: #fff;
}

.player-role-tag {
  font-size: 10.5px;
  font-weight: 700;
  color: var(--muted);
}

.captured-tray {
  display: flex;
  align-items: center;
  gap: 2px;
  min-height: 20px;
}

.captured-mini-svg {
  width: 20px;
  height: 20px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.captured-mini-svg .chess-piece-svg {
  width: 100%;
  height: 100%;
  filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.4));
  transform: none;
}

.captured-diff {
  font-size: 11px;
  font-weight: 800;
  color: var(--gold);
  margin-left: 4px;
}

/* Digital Chess Clock */
.digital-clock {
  font-family: 'JetBrains Mono', monospace;
  font-size: 18px;
  font-weight: 800;
  padding: 4px 10px;
  border-radius: 8px;
  background: rgba(7, 11, 20, 0.85);
  border: 1px solid rgba(255, 255, 255, 0.12);
  color: #cbd5e1;
  letter-spacing: 0.05em;
  transition: all 0.2s ease;
}

.digital-clock.running {
  color: #fff;
  border-color: var(--cyan);
  box-shadow: 0 0 10px var(--cyan-glow);
}

.digital-clock.low-time {
  color: #fb7185;
  border-color: #f43f5e;
  animation: pulseBeacon 1s infinite;
}

/* ================= CHESSBOARD BOARD FRAME ================= */
.board-wrapper {
  position: relative;
  width: 100%;
  max-width: 590px;
  aspect-ratio: 1 / 1;
  background: var(--board-frame-gradient);
  border-radius: 18px;
  border: 4px solid var(--board-gold-hairline);
  box-shadow: 
    0 24px 60px rgba(0, 0, 0, 0.9),
    0 8px 24px rgba(0, 0, 0, 0.6),
    inset 0 2px 5px rgba(255, 255, 255, 0.22),
    inset 0 -2px 6px rgba(0, 0, 0, 0.85);
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
  user-select: none;
  overflow: hidden;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Tọa độ viền trên & dưới (Files a-h) */
.board-coords-top,
.board-coords-bottom {
  height: var(--board-border-thickness);
  padding: 0 var(--board-border-thickness);
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  align-items: center;
  justify-items: center;
  box-sizing: border-box;
  flex-shrink: 0;
}

/* Khung giữa gồm Viền trái, Bàn cờ 64 ô, Viền phải */
.board-middle-container {
  flex: 1;
  display: flex;
  align-items: stretch;
  width: 100%;
  min-height: 0;
}

/* Tọa độ viền trái & phải (Ranks 1-8) */
.board-coords-left,
.board-coords-right {
  width: var(--board-border-thickness);
  display: grid;
  grid-template-rows: repeat(8, 1fr);
  align-items: center;
  justify-items: center;
  box-sizing: border-box;
  flex-shrink: 0;
}

/* Ký tự & chữ số tọa độ hiển thị trên viền ngoài ô cờ */
.border-coord {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  font-weight: 800;
  color: var(--coord-border-color);
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.95);
  pointer-events: none;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0.95;
  transition: color 0.2s ease;
}

@media (max-width: 600px) {
  :root {
    --board-border-thickness: 20px;
  }
  .border-coord {
    font-size: 10px;
  }
}

/* 64 ô cờ nằm trọn vẹn trong khung viền */
.chessboard {
  flex: 1;
  height: 100%;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  border-radius: 4px;
  overflow: hidden;
  position: relative;
  box-shadow: inset 0 0 12px rgba(0, 0, 0, 0.5), 0 0 0 2px var(--board-inlay-border);
}

.sq {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  cursor: pointer;
  user-select: none;
  overflow: hidden;
  transition: background-color 0.15s ease;
}

.sq.light {
  background-color: var(--sq-light);
}

.sq.dark {
  background-color: var(--sq-dark);
}

/* Square highlights - Ô cờ đang chọn */
.sq.selected {
  background: radial-gradient(circle at 50% 50%, rgba(251, 191, 36, 0.45) 0%, rgba(217, 119, 6, 0.65) 100%) !important;
  box-shadow: inset 0 0 0 2.5px rgba(254, 240, 138, 0.85), 0 0 16px rgba(245, 158, 11, 0.45) !important;
}

body[data-board-theme="tournament"] .sq.selected {
  background: radial-gradient(circle at 50% 50%, rgba(186, 202, 68, 0.55) 0%, rgba(132, 150, 40, 0.75) 100%) !important;
  box-shadow: inset 0 0 0 2.5px rgba(247, 236, 105, 0.85), 0 0 16px rgba(186, 202, 68, 0.45) !important;
}

body[data-board-theme="obsidian"] .sq.selected {
  background: radial-gradient(circle at 50% 50%, rgba(0, 242, 254, 0.4) 0%, rgba(2, 132, 199, 0.6) 100%) !important;
  box-shadow: inset 0 0 0 2.5px rgba(186, 230, 253, 0.85), 0 0 16px rgba(0, 242, 254, 0.5) !important;
}

/* Nâng bổng quân cờ đang chọn 3D */
.sq.selected .piece-wrapper .chess-piece-svg {
  transform: translateY(-5px) scale(1.1);
  filter: drop-shadow(0 10px 14px rgba(0, 0, 0, 0.65)) drop-shadow(0 0 8px rgba(251, 191, 36, 0.5));
}

/* Nước đi trước đó (Last Move) */
.sq.last-move {
  background: radial-gradient(circle at 50% 50%, rgba(234, 179, 8, 0.35) 0%, rgba(180, 83, 9, 0.4) 100%) !important;
  box-shadow: inset 0 0 0 1.5px rgba(251, 191, 36, 0.5) !important;
}

body[data-board-theme="tournament"] .sq.last-move {
  background: radial-gradient(circle at 50% 50%, rgba(247, 236, 105, 0.45) 0%, rgba(186, 202, 68, 0.45) 100%) !important;
  box-shadow: inset 0 0 0 1.5px rgba(247, 236, 105, 0.5) !important;
}

body[data-board-theme="obsidian"] .sq.last-move {
  background: radial-gradient(circle at 50% 50%, rgba(56, 189, 248, 0.35) 0%, rgba(3, 105, 161, 0.4) 100%) !important;
  box-shadow: inset 0 0 0 1.5px rgba(56, 189, 248, 0.5) !important;
}

/* King bị chiếu */
.sq.in-check {
  background: radial-gradient(circle, rgba(239, 68, 68, 0.95) 0%, rgba(220, 38, 38, 0.6) 65%, rgba(185, 28, 28, 0.25) 100%) !important;
  animation: checkPulse 1s infinite alternate;
}

@keyframes checkPulse {
  0% { box-shadow: inset 0 0 12px rgba(239, 68, 68, 0.7); }
  100% { box-shadow: inset 0 0 26px rgba(239, 68, 68, 1); }
}

/* ================= MOVE DESTINATION INDICATORS ================= */
/* Chấm tròn di chuyển ô trống (Thanh lịch, hiệu ứng thấu kính quang học) */
.sq .hint-dot {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 28%;
  height: 28%;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, rgba(45, 30, 20, 0.35) 0%, rgba(15, 10, 5, 0.55) 100%);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.3), 0 2px 4px rgba(0, 0, 0, 0.35);
  pointer-events: none;
  z-index: 3;
  transition: all 0.15s cubic-bezier(0.16, 1, 0.3, 1);
  animation: scaleIn 0.18s ease;
}

body[data-board-theme="tournament"] .sq .hint-dot {
  background: radial-gradient(circle at 35% 35%, rgba(20, 45, 20, 0.35) 0%, rgba(5, 20, 5, 0.55) 100%);
}

body[data-board-theme="obsidian"] .sq .hint-dot {
  background: radial-gradient(circle at 35% 35%, rgba(255, 255, 255, 0.55) 0%, rgba(203, 213, 225, 0.35) 100%);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.8), 0 0 8px rgba(0, 242, 254, 0.4);
}

/* Hover mượt mà vào ô đích hợp lệ */
.sq.valid-target:hover {
  background-color: rgba(245, 158, 11, 0.18) !important;
}

.sq.valid-target:hover .hint-dot {
  width: 38%;
  height: 38%;
  background: radial-gradient(circle at 40% 40%, rgba(251, 191, 36, 0.95) 0%, rgba(217, 119, 6, 0.95) 100%);
  box-shadow: 0 0 16px rgba(245, 158, 11, 0.9), inset 0 1px 2px #fff;
  transform: translate(-50%, -50%) scale(1.15);
}

body[data-board-theme="obsidian"] .sq.valid-target:hover .hint-dot {
  background: radial-gradient(circle at 40% 40%, #38bdf8 0%, #0284c7 100%);
  box-shadow: 0 0 16px rgba(56, 189, 248, 0.9), inset 0 1px 2px #fff;
}

/* Ô có quân đối thủ có thể ăn (Capture Target) - KHÔNG khoanh tròn quân cờ, phủ màu nền ô tinh tế */
.sq.capture-target {
  background-color: rgba(239, 68, 68, 0.2) !important;
  box-shadow: inset 0 0 0 2px rgba(239, 68, 68, 0.5) !important;
  transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.sq.capture-target:hover {
  background-color: rgba(239, 68, 68, 0.38) !important;
  box-shadow: inset 0 0 0 3px #ef4444, inset 0 0 16px rgba(239, 68, 68, 0.55) !important;
}

body[data-board-theme="obsidian"] .sq.capture-target {
  background-color: rgba(244, 63, 94, 0.22) !important;
  box-shadow: inset 0 0 0 2px rgba(244, 63, 94, 0.55) !important;
}

body[data-board-theme="obsidian"] .sq.capture-target:hover {
  background-color: rgba(244, 63, 94, 0.4) !important;
  box-shadow: inset 0 0 0 3px #f43f5e, inset 0 0 18px rgba(244, 63, 94, 0.6) !important;
}

@keyframes scaleIn {
  from { transform: scale(0.4); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

/* Huy hiệu Nhập Thành cao cấp (Castling Badge) */
.sq .hint-castle-badge {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 4px 10px;
  border-radius: 16px;
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.95) 0%, rgba(217, 119, 6, 0.95) 100%);
  border: 2px solid #fef08a;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  font-family: 'Plus Jakarta Sans', sans-serif;
  font-size: 11.5px;
  font-weight: 900;
  color: #1e1b4b;
  text-shadow: 0 1px 1px rgba(254, 240, 138, 0.6);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.5), 0 0 16px rgba(245, 158, 11, 0.85);
  pointer-events: none;
  z-index: 4;
  white-space: nowrap;
  transition: all 0.15s cubic-bezier(0.16, 1, 0.3, 1);
  animation: castleBadgePulse 1s infinite alternate;
}

.sq .hint-castle-badge .castle-text {
  letter-spacing: 0.05em;
}

.sq.valid-target:hover .hint-castle-badge {
  transform: translate(-50%, -50%) scale(1.15);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.6), 0 0 24px rgba(251, 191, 36, 1);
}

@keyframes castleBadgePulse {
  0% {
    transform: translate(-50%, -50%) scale(0.94);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4), 0 0 10px rgba(245, 158, 11, 0.6);
  }
  100% {
    transform: translate(-50%, -50%) scale(1.06);
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.5), 0 0 20px rgba(245, 158, 11, 0.95);
  }
}

/* Khung căn giữa hoàn hảo cho quân cờ (Dead Center 100%) */
.piece-wrapper {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  z-index: 2;
}

.piece-wrapper .chess-piece-svg {
  width: 82%;
  height: 82%;
  max-width: 82%;
  max-height: 82%;
  display: block;
  margin: auto;
  pointer-events: none;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.42));
  transition: transform 0.12s cubic-bezier(0.16, 1, 0.3, 1), filter 0.12s ease;
  user-select: none;
}

.sq:hover .piece-wrapper .chess-piece-svg {
  transform: translateY(-2px) scale(1.05);
  filter: drop-shadow(0 6px 10px rgba(0, 0, 0, 0.55));
}

/* Turn & Game Status Banner */
.game-status-banner {
  width: 100%;
  max-width: 580px;
  padding: 8px 14px;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 800;
  text-align: center;
  background: rgba(14, 23, 42, 0.85);
  border: 1px solid var(--panel-border);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.game-status-banner.your-turn {
  background: rgba(0, 242, 254, 0.15);
  border-color: rgba(0, 242, 254, 0.4);
  color: var(--cyan);
}

.game-status-banner.check-alert {
  background: rgba(244, 63, 94, 0.2);
  border-color: rgba(244, 63, 94, 0.5);
  color: #fb7185;
}

/* Promotion Modal */
.promotion-modal-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.promotion-modal-overlay.show {
  opacity: 1;
  pointer-events: auto;
}

.promotion-card {
  background: rgba(15, 23, 42, 0.95);
  border: 1.5px solid var(--cyan);
  border-radius: 16px;
  padding: 16px 20px;
  text-align: center;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.8), 0 0 25px var(--cyan-glow);
}

.promotion-card h4 {
  font-size: 14px;
  font-weight: 900;
  color: #fff;
  margin-bottom: 12px;
}

.promotion-options-row {
  display: flex;
  gap: 10px;
}

.promo-opt-btn {
  width: 60px;
  height: 60px;
  border-radius: 12px;
  background: rgba(22, 34, 58, 0.8);
  border: 1.5px solid rgba(255, 255, 255, 0.15);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
  transition: all 0.2s ease;
}

.promo-opt-btn:hover {
  background: rgba(0, 242, 254, 0.25);
  border-color: var(--cyan);
  transform: translateY(-3px);
  box-shadow: 0 8px 20px var(--cyan-glow);
}

/* ================= COLUMN 3: MOVES & CHAT ================= */
.move-history-box {
  background: rgba(7, 11, 20, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  height: 210px;
  overflow-y: auto;
  padding: 8px;
}

.move-history-table {
  width: 100%;
  border-collapse: collapse;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
}

.move-history-table th {
  color: var(--muted);
  font-weight: 700;
  padding: 4px 6px;
  text-align: left;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.move-history-table td {
  padding: 4px 6px;
  color: #e2e8f0;
}

.move-num {
  color: var(--muted);
  width: 28px;
}

.move-history-table tr.active-move {
  background: rgba(0, 242, 254, 0.12);
  color: var(--cyan);
}

/* Chat container */
.chat-container {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.chat-messages {
  background: rgba(7, 11, 20, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  height: 180px;
  overflow-y: auto;
  padding: 10px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.chat-bubble {
  font-size: 12.5px;
  padding: 6px 10px;
  border-radius: 10px;
  max-width: 85%;
  word-break: break-word;
  line-height: 1.4;
}

.chat-bubble.mine {
  align-self: flex-end;
  background: linear-gradient(135deg, rgba(0, 242, 254, 0.2), rgba(2, 132, 199, 0.35));
  border: 1px solid rgba(0, 242, 254, 0.35);
  color: #fff;
}

.chat-bubble.opp {
  align-self: flex-start;
  background: rgba(30, 41, 59, 0.75);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: #f1f5f9;
}

.chat-bubble .chat-sender {
  font-size: 10px;
  font-weight: 800;
  color: var(--cyan);
  margin-bottom: 2px;
}

.chat-bubble.mine .chat-sender {
  color: #a5f3fc;
}

.chat-input-row {
  display: flex;
  gap: 6px;
}

.chat-input {
  flex: 1;
  background: rgba(7, 11, 20, 0.9);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 10px;
  padding: 8px 12px;
  color: #fff;
  font-size: 12.5px;
  outline: none;
}

.chat-input:focus {
  border-color: var(--cyan);
}

.chat-send-btn {
  background: rgba(0, 242, 254, 0.2);
  border: 1px solid rgba(0, 242, 254, 0.35);
  color: var(--cyan);
  padding: 0 12px;
  border-radius: 10px;
  font-weight: 800;
  cursor: pointer;
}

/* Quick Emojis */
.emoji-quick-row {
  display: flex;
  justify-content: space-between;
  gap: 4px;
}

.emoji-btn {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 16px;
  padding: 4px 8px;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.emoji-btn:hover {
  transform: scale(1.2);
  background: rgba(255, 255, 255, 0.12);
}

/* Toast Container */
.chess-toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(30px);
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid rgba(0, 242, 254, 0.4);
  color: #fff;
  padding: 10px 22px;
  border-radius: 99px;
  font-size: 13px;
  font-weight: 700;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.6), 0 0 20px var(--cyan-glow);
  z-index: 9999;
  opacity: 0;
  pointer-events: none;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.chess-toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* Dialog Modal */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
  padding: 16px;
}

.modal-overlay.show {
  opacity: 1;
  pointer-events: auto;
}

.modal-box {
  background: rgba(15, 23, 42, 0.95);
  border: 1.5px solid var(--panel-border-glow);
  border-radius: 18px;
  padding: 24px;
  max-width: 420px;
  width: 100%;
  text-align: center;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.8), 0 0 30px var(--cyan-glow);
}

.modal-box h3 {
  font-size: 18px;
  font-weight: 900;
  color: #fff;
  margin-bottom: 8px;
}

.modal-box p {
  font-size: 13.5px;
  color: var(--muted);
  margin-bottom: 20px;
}

.modal-actions-row {
  display: flex;
  gap: 10px;
}

/* ================= RESPONSIVE ================= */
@media (max-width: 1100px) {
  .layout-three-cols {
    grid-template-columns: 280px 1fr 280px;
    gap: 12px;
  }
}

@media (max-width: 900px) {
  .layout-three-cols {
    grid-template-columns: 1fr;
  }
  .col-board-container {
    order: 1;
  }
  .col-panel.col-setup {
    order: 2;
  }
  .col-panel.col-moves-chat {
    order: 3;
  }
  .board-wrapper {
    max-width: min(92vw, 480px);
  }
}

@media (max-width: 520px) {
  .top-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }
  .header-actions {
    width: 100%;
    justify-content: space-between;
  }
  .board-wrapper {
    padding: 4px;
  }
}