/* ==========================================================================
   SPRAWL — MODERN LUXURY GLASSMORPHIC DESIGN SYSTEM
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@400;500;600;700;800&family=Plus+Jakarta+Sans:wght@400;500;600;700&family=JetBrains+Mono:wght@500;600&display=swap');

:root {
  --font-display: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Default Dark Mode (Deep Midnight Neo-Glass) */
  --bg-base: #0a0d14;
  --bg-gradient: radial-gradient(circle at 50% 0%, #161b2e 0%, #0a0d14 70%);
  --panel-bg: rgba(18, 22, 36, 0.72);
  --panel-bg-solid: #121624;
  --panel-sub: rgba(26, 32, 53, 0.6);
  --panel-border: rgba(255, 255, 255, 0.08);
  --panel-border-hover: rgba(255, 255, 255, 0.16);
  --panel-border-glow: rgba(99, 102, 241, 0.25);

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --x-color: #38bdf8;
  --x-gradient: linear-gradient(135deg, #38bdf8, #6366f1);
  --x-glow: rgba(56, 189, 248, 0.35);
  --x-bg: rgba(56, 189, 248, 0.12);

  --o-color: #fb7185;
  --o-gradient: linear-gradient(135deg, #fb7185, #f97316);
  --o-glow: rgba(251, 113, 133, 0.35);
  --o-bg: rgba(251, 113, 133, 0.12);

  --accent-green: #34d399;
  --accent-green-glow: rgba(52, 211, 153, 0.35);
  --accent-green-bg: rgba(52, 211, 153, 0.12);

  --accent-amber: #fbbf24;
  --accent-amber-bg: rgba(251, 191, 36, 0.12);

  --accent-blue: #60a5fa;
  --accent-teal: #2dd4bf;

  --cell-bg: rgba(28, 36, 62, 0.75);
  --cell-border: rgba(255, 255, 255, 0.14);
  --cell-hover-border: rgba(56, 189, 248, 0.8);
  --cell-hover-bg: rgba(38, 50, 86, 0.95);
  --cell-shadow: 0 6px 16px rgba(0, 0, 0, 0.45), inset 0 1px 1px rgba(255, 255, 255, 0.14);

  --slot-border: rgba(52, 211, 153, 0.45);
  --slot-bg: rgba(52, 211, 153, 0.04);
  --slot-hover-bg: rgba(52, 211, 153, 0.16);
  --slot-hover-border: #34d399;

  --btn-bg: rgba(26, 32, 53, 0.7);
  --btn-border: rgba(255, 255, 255, 0.1);
  --btn-text: #e2e8f0;
  --btn-hover-bg: rgba(40, 49, 78, 0.85);
  --btn-hover-border: rgba(255, 255, 255, 0.22);
  --btn-active-bg: #4f46e5;
  --btn-active-text: #ffffff;

  --shadow-lg: 0 20px 40px -15px rgba(0, 0, 0, 0.6), 0 0 1px 1px rgba(255, 255, 255, 0.05);
  --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.45);
  --shadow-glow: 0 0 30px -5px var(--panel-border-glow);

  --grid-line: rgba(255, 255, 255, 0.03);
}

/* Light Theme */
:root[data-theme="light"] {
  --bg-base: #f8fafc;
  --bg-gradient: radial-gradient(circle at 50% 0%, #e2e8f0 0%, #f8fafc 75%);
  --panel-bg: rgba(255, 255, 255, 0.88);
  --panel-bg-solid: #ffffff;
  --panel-sub: rgba(241, 245, 249, 0.85);
  --panel-border: rgba(0, 0, 0, 0.1);
  --panel-border-hover: rgba(0, 0, 0, 0.2);
  --panel-border-glow: rgba(79, 70, 229, 0.18);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;

  --x-color: #0284c7;
  --x-gradient: linear-gradient(135deg, #0284c7, #4f46e5);
  --x-glow: rgba(2, 132, 199, 0.25);
  --x-bg: rgba(2, 132, 199, 0.08);

  --o-color: #e11d48;
  --o-gradient: linear-gradient(135deg, #e11d48, #ea580c);
  --o-glow: rgba(225, 29, 72, 0.25);
  --o-bg: rgba(225, 29, 72, 0.08);

  --accent-green: #059669;
  --accent-green-glow: rgba(5, 150, 105, 0.25);
  --accent-green-bg: rgba(5, 150, 105, 0.08);

  --accent-amber: #d97706;
  --accent-amber-bg: rgba(217, 119, 6, 0.08);

  --accent-blue: #2563eb;
  --accent-teal: #0d9488;

  --cell-bg: #edf2f7;
  --cell-border: rgba(0, 0, 0, 0.14);
  --cell-hover-border: #0284c7;
  --cell-hover-bg: #e0f2fe;
  --cell-shadow: 0 4px 10px rgba(0, 0, 0, 0.08), inset 0 1px 1px rgba(255, 255, 255, 0.9);

  --slot-border: rgba(5, 150, 105, 0.45);
  --slot-bg: rgba(5, 150, 105, 0.04);
  --slot-hover-bg: rgba(5, 150, 105, 0.12);
  --slot-hover-border: #059669;

  --btn-bg: #ffffff;
  --btn-border: rgba(0, 0, 0, 0.12);
  --btn-text: #1e293b;
  --btn-hover-bg: #f1f5f9;
  --btn-hover-border: rgba(0, 0, 0, 0.22);
  --btn-active-bg: #0f172a;
  --btn-active-text: #ffffff;

  --shadow-lg: 0 20px 35px -10px rgba(0, 0, 0, 0.1), 0 0 1px 1px rgba(0, 0, 0, 0.04);
  --shadow-card: 0 6px 18px -3px rgba(0, 0, 0, 0.07);
  --shadow-glow: 0 0 25px -3px rgba(99, 102, 241, 0.15);

  --grid-line: rgba(0, 0, 0, 0.025);
}

/* ==========================================================================
   GLOBAL RESET & BASE STYLES
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

html, body {
  position: relative;
  min-height: 100vh;
  min-height: 100dvh;
  font-family: var(--font-body);
  color: var(--text-primary);
  background-color: var(--bg-base);
  background-image:
    radial-gradient(circle at 15% 15%, color-mix(in srgb, var(--x-color) 12%, transparent), transparent 35%),
    radial-gradient(circle at 85% 20%, color-mix(in srgb, var(--o-color) 12%, transparent), transparent 40%),
    radial-gradient(circle at 50% 85%, color-mix(in srgb, var(--accent-green) 8%, transparent), transparent 45%),
    var(--bg-gradient);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  line-height: 1.5;
  overflow-x: hidden;
}

@media (min-width: 769px) and (min-height: 500px) {
  html, body {
    background-attachment: fixed;
  }
}

button, .sq, .ctl {
  -webkit-tap-highlight-color: transparent;
}

.sq {
  -webkit-touch-callout: none;
}

/* Background Subtle Tech Grid */
body::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--grid-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--grid-line) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
  z-index: 0;
}

/* Confetti Canvas */
#confettiCanvas {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 9999;
}

/* Main Layout Wrapper */
.app-container {
  position: relative;
  z-index: 1;
  max-width: 1080px;
  margin: 0 auto;
  padding: 24px 20px 60px;
  padding-left: max(20px, env(safe-area-inset-left));
  padding-right: max(20px, env(safe-area-inset-right));
  padding-bottom: max(60px, env(safe-area-inset-bottom));
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ==========================================================================
   NAVBAR & HEADER
   ========================================================================== */

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 22px;
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  border-radius: 20px;
  box-shadow: var(--shadow-card);
}

.brand-section {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-icon {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--x-color), var(--o-color));
  padding: 2px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 14px var(--x-glow);
}

.brand-icon-inner {
  width: 100%;
  height: 100%;
  background: var(--panel-bg-solid);
  border-radius: 10px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 3px;
  padding: 6px;
}

.brand-icon-inner span {
  border-radius: 3px;
  background: var(--panel-border);
}
.brand-icon-inner span:nth-child(1) { background: var(--x-color); }
.brand-icon-inner span:nth-child(4) { background: var(--o-color); }

.brand-title-group h1 {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.1;
  background: linear-gradient(120deg, var(--text-primary) 30%, var(--x-color) 70%, var(--accent-green));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.brand-badge {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.icon-btn {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--btn-bg);
  border: 1px solid var(--btn-border);
  color: var(--btn-text);
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  font-size: 17px;
}

.icon-btn:hover {
  background: var(--btn-hover-bg);
  border-color: var(--btn-hover-border);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.icon-btn:active {
  transform: translateY(0) scale(0.95);
}

.btn-label-icon {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 16px;
  border-radius: 12px;
  background: var(--btn-bg);
  border: 1px solid var(--btn-border);
  color: var(--btn-text);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-label-icon:hover {
  background: var(--btn-hover-bg);
  border-color: var(--btn-hover-border);
  transform: translateY(-2px);
}

.rating-badge {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--panel-sub);
  color: var(--text-primary);
  border: 1px solid var(--panel-border);
  white-space: nowrap;
}

/* ==========================================================================
   SCOREBOARD & TURN HUD
   ========================================================================== */

.hud-section {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 16px;
}

.player-card {
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  border-radius: 20px;
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: var(--shadow-card);
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  position: relative;
  overflow: hidden;
}

.player-card::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  width: 4px;
  background: transparent;
  transition: all 0.3s ease;
}

.player-card.x-card::before {
  left: 0;
  background: var(--x-color);
  opacity: 0.3;
}

.player-card.o-card::before {
  right: 0;
  background: var(--o-color);
  opacity: 0.3;
}

.player-card.active-turn {
  border-color: var(--panel-border-hover);
  box-shadow: 0 8px 30px -8px var(--shadow-glow);
  transform: translateY(-2px);
}

.player-card.x-card.active-turn {
  border-color: color-mix(in srgb, var(--x-color) 40%, var(--panel-border));
  box-shadow: 0 10px 30px -8px var(--x-glow);
}
.player-card.x-card.active-turn::before {
  opacity: 1;
  box-shadow: 0 0 12px var(--x-color);
}

.player-card.o-card.active-turn {
  border-color: color-mix(in srgb, var(--o-color) 40%, var(--panel-border));
  box-shadow: 0 10px 30px -8px var(--o-glow);
}
.player-card.o-card.active-turn::before {
  opacity: 1;
  box-shadow: 0 0 12px var(--o-color);
}

.player-avatar-wrapper {
  position: relative;
}

.player-avatar {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 800;
  transition: all 0.3s ease;
}

.x-card .player-avatar {
  background: var(--x-bg);
  color: var(--x-color);
  border: 1px solid color-mix(in srgb, var(--x-color) 30%, transparent);
}

.o-card .player-avatar {
  background: var(--o-bg);
  color: var(--o-color);
  border: 1px solid color-mix(in srgb, var(--o-color) 30%, transparent);
}

.player-turn-pulse {
  position: absolute;
  inset: -4px;
  border-radius: 18px;
  border: 2px solid transparent;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.player-card.active-turn .player-turn-pulse {
  opacity: 1;
  animation: pulseHalo 2s infinite ease-in-out;
}

.x-card.active-turn .player-turn-pulse {
  border-color: var(--x-color);
}

.o-card.active-turn .player-turn-pulse {
  border-color: var(--o-color);
}

@keyframes pulseHalo {
  0% { transform: scale(1); opacity: 0.8; }
  50% { transform: scale(1.1); opacity: 0.2; }
  100% { transform: scale(1); opacity: 0.8; }
}

.player-info {
  flex: 1;
  min-width: 0;
}

.player-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.player-name {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  color: var(--text-primary);
}

.player-role-badge {
  font-size: 11px;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--panel-sub);
  color: var(--text-secondary);
  border: 1px solid var(--panel-border);
}

.player-score-row {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin-top: 2px;
}

.player-score {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
}

.score-caption {
  font-size: 12px;
  color: var(--text-muted);
}

.hud-center-pill {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  text-align: center;
  padding: 10px 18px;
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  border-radius: 999px;
  box-shadow: var(--shadow-card);
}

.versus-tag {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.match-round-count {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  font-family: var(--font-mono);
}

/* ==========================================================================
   TURN STATUS BANNER & PHASE GUIDE
   ========================================================================== */

.turn-banner {
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  border-radius: 18px;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  box-shadow: var(--shadow-card);
}

.turn-status-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.status-dot-indicator {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--x-color);
  box-shadow: 0 0 10px var(--x-glow);
  transition: all 0.3s ease;
}

.status-title-group {
  display: flex;
  flex-direction: column;
}

.who-text {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.2;
}

.hint-text {
  font-size: 13px;
  color: var(--text-secondary);
}

.phase-stepper {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px;
  background: var(--panel-sub);
  border: 1px solid var(--panel-border);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}

.step-chip {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.step-chip.active {
  color: var(--text-primary);
}

.step-num {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--panel-border);
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 10px;
  font-family: var(--font-mono);
  font-weight: 700;
}

.step-chip.active .step-num {
  background: var(--x-color);
  color: #ffffff;
}

.step-divider {
  color: var(--text-muted);
  font-size: 11px;
}

/* ==========================================================================
   GAMEPLAY ARENA & BOARD
   ========================================================================== */

.arena-card {
  background: var(--panel-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--panel-border);
  border-radius: 24px;
  padding: 24px;
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

.arena-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 15%;
  right: 15%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--x-color), var(--o-color), transparent);
  opacity: 0.8;
}

.board-viewport {
  position: relative;
  min-height: 380px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 30px 10px;
  background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.02) 0%, transparent 70%);
  border-radius: 18px;
  overflow: auto;
}

.board {
  display: grid;
  justify-content: center;
  align-content: center;
  gap: 10px;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Square Styling */
.sq {
  position: relative;
  border: 0;
  padding: 0;
  margin: 0;
  background: none;
  font: inherit;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.15s cubic-bezier(0.16, 1, 0.3, 1),
              box-shadow 0.2s ease,
              border-color 0.2s ease,
              background-color 0.2s ease;
  user-select: none;
  -webkit-user-select: none;
}

/* Open Squares (clickable in place phase) */
.sq.open {
  background: var(--cell-bg);
  border: 1px solid var(--cell-border);
  box-shadow: var(--cell-shadow);
  cursor: pointer;
}

.sq.open::after {
  content: "";
  position: absolute;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--text-muted);
  opacity: 0.25;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.sq.open:hover::after {
  opacity: 0.9;
  background: var(--x-color);
  transform: scale(2);
  box-shadow: 0 0 10px var(--x-glow);
}

.sq.open:hover {
  border-color: var(--cell-hover-border);
  background: var(--cell-hover-bg);
  transform: translateY(-3px) scale(1.03);
  box-shadow: 0 10px 20px -5px rgba(0, 0, 0, 0.4), 0 0 15px var(--x-glow);
}

.sq.open:active {
  transform: translateY(0) scale(0.96);
}

/* Taken Squares (contain marks) */
.sq.taken {
  background: var(--cell-bg);
  border: 1px solid var(--cell-border);
  box-shadow: var(--cell-shadow);
  cursor: default;
}

/* SVG Mark Styling */
.mark-svg {
  width: 65%;
  height: 65%;
  display: block;
  filter: drop-shadow(0 2px 6px rgba(0,0,0,0.4));
  animation: markSpring 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes markSpring {
  0% { transform: scale(0.2) rotate(-20deg); opacity: 0; }
  100% { transform: scale(1) rotate(0); opacity: 1; }
}

.mark-svg.mark-x {
  color: var(--x-color);
  filter: drop-shadow(0 0 8px var(--x-glow));
}

.mark-svg.mark-x line {
  stroke-dasharray: 85;
  stroke-dashoffset: 85;
  animation: drawLine 0.24s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.mark-svg.mark-x line:nth-child(2) {
  animation-delay: 0.08s;
}

@keyframes drawLine {
  to { stroke-dashoffset: 0; }
}

.mark-svg.mark-o {
  color: var(--o-color);
  filter: drop-shadow(0 0 8px var(--o-glow));
}

.mark-svg.mark-o circle {
  stroke-dasharray: 210;
  stroke-dashoffset: 210;
  animation: drawCircle 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes drawCircle {
  to { stroke-dashoffset: 0; }
}

/* Growth Slot (+ squares edge-to-edge) */
.sq.slot {
  background: var(--slot-bg);
  border: 2px dashed var(--slot-border);
  color: var(--accent-green);
  cursor: pointer;
  animation: slotPulse 2.5s infinite ease-in-out;
}

@keyframes slotPulse {
  0%, 100% { border-color: var(--slot-border); transform: scale(1); }
  50% { border-color: var(--accent-green); transform: scale(1.02); }
}

.sq.slot:hover {
  background: var(--slot-hover-bg);
  border-color: var(--slot-hover-border);
  border-style: solid;
  transform: translateY(-3px) scale(1.06);
  box-shadow: 0 8px 20px -4px var(--accent-green-glow);
}

.sq.slot:active {
  transform: translateY(0) scale(0.96);
}

.slot-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--accent-green-bg);
  color: var(--accent-green);
  font-size: 16px;
  font-weight: 700;
  transition: transform 0.2s ease;
}

.sq.slot:hover .slot-icon {
  transform: rotate(90deg) scale(1.15);
  background: var(--accent-green);
  color: #0f172a;
}

/* Void cell */
.sq.void {
  visibility: hidden;
  pointer-events: none;
}

/* Freshly placed / grown square pop */
.sq.fresh {
  animation: freshTile 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes freshTile {
  0% { transform: scale(0.4); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

/* Last Placed Mark Highlight */
.sq.last-placed {
  position: relative;
  border: 2.5px solid currentColor !important;
  box-shadow: 0 0 0 3px color-mix(in srgb, currentColor 35%, transparent), 0 0 22px color-mix(in srgb, currentColor 65%, transparent) !important;
  z-index: 6;
}

.sq.last-placed::before {
  content: "";
  position: absolute;
  top: 6px;
  left: 6px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: currentColor;
  box-shadow: 0 0 8px currentColor;
  animation: lastMoveDotPulse 1.5s infinite ease-in-out;
  pointer-events: none;
  z-index: 7;
}

@keyframes lastMoveDotPulse {
  0%, 100% { transform: scale(1); opacity: 0.9; }
  50% { transform: scale(1.4); opacity: 0.45; }
}

.sq.last-placed::after {
  content: "";
  position: absolute;
  inset: -6px;
  border-radius: 18px;
  border: 2px solid currentColor;
  animation: lastMoveBeacon 1.8s infinite ease-out;
  pointer-events: none;
}

@keyframes lastMoveBeacon {
  0% { transform: scale(0.96); opacity: 0.9; }
  60% { transform: scale(1.16); opacity: 0.1; }
  100% { transform: scale(1.22); opacity: 0; }
}

/* Last Grown Empty Square Highlight — Simple, Subtle & Clean */
.sq.last-grown {
  border: 2px solid var(--panel-border-hover) !important;
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.08) !important;
  background: color-mix(in srgb, var(--text-primary) 5%, transparent) !important;
  position: relative;
  z-index: 5;
}

/* Last Move Badge in Status Banner */
.last-move-badge {
  font-size: 11px;
  font-family: var(--font-mono);
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--panel-sub);
  border: 1px solid var(--panel-border-hover);
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 5px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
  animation: badgeSlideIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.last-move-badge[hidden] {
  display: none !important;
}

.last-move-badge b {
  color: var(--text-primary);
}

@keyframes badgeSlideIn {
  from { opacity: 0; transform: translateX(-6px); }
  to { opacity: 1; transform: translateX(0); }
}

/* Winning line highlights */
.sq.win {
  border-color: currentColor !important;
  border-width: 2px !important;
  box-shadow: 0 0 25px currentColor, inset 0 0 15px currentColor !important;
  animation: winGlow 1.2s infinite alternate ease-in-out;
  z-index: 10;
}

@keyframes winGlow {
  0% { transform: scale(1); filter: brightness(1); }
  100% { transform: scale(1.08); filter: brightness(1.35); }
}

/* Tactical Threat Indicator Pip */
.pip {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  top: 6px;
  right: 6px;
  box-shadow: 0 0 0 2px var(--panel-bg-solid), 0 0 8px currentColor;
  animation: pipPulse 1.5s infinite ease-in-out;
}

@keyframes pipPulse {
  0%, 100% { transform: scale(1); opacity: 0.9; }
  50% { transform: scale(1.3); opacity: 0.4; }
}

/* Hint highlighting from analysis */
.sq.hintsq {
  outline: 2.5px solid var(--accent-green) !important;
  outline-offset: -2px;
  box-shadow: 0 0 15px var(--accent-green-glow);
}

.sq.hintgrow {
  outline: 2.5px dashed var(--accent-green) !important;
  outline-offset: -2px;
  box-shadow: 0 0 15px var(--accent-green-glow);
}

.sq:focus-visible {
  outline: 2.5px solid var(--x-color);
  outline-offset: 2px;
}

/* ==========================================================================
   PRIMARY CONTROLS & TOOLBARS
   ========================================================================== */

.controls-wrapper {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid var(--panel-border);
}

.primary-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.primary-toolbar[hidden] {
  display: none;
}

/* Segmented Control Switcher */
.segmented-grp {
  display: inline-flex;
  padding: 4px;
  background: var(--panel-sub);
  border: 1px solid var(--panel-border);
  border-radius: 999px;
  gap: 2px;
}

.segmented-grp button.ctl.seg {
  border: 0;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  padding: 7px 16px;
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.segmented-grp button.ctl.seg:hover {
  color: var(--text-primary);
}

.segmented-grp button.ctl.seg[aria-pressed="true"] {
  background: var(--btn-active-bg);
  color: var(--btn-active-text);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

/* Action Buttons Group */
.action-buttons-grp {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

button.ctl {
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  padding: 8px 16px;
  border-radius: 999px;
  background: var(--btn-bg);
  border: 1px solid var(--btn-border);
  color: var(--btn-text);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

button.ctl:hover {
  background: var(--btn-hover-bg);
  border-color: var(--btn-hover-border);
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
}

button.ctl:active {
  transform: translateY(0);
}

button.ctl:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none !important;
  box-shadow: none !important;
}

button.ctl.primary-btn {
  background: linear-gradient(135deg, #4f46e5, #6366f1);
  color: #ffffff;
  border: none;
  box-shadow: 0 4px 14px rgba(79, 70, 229, 0.35);
}

button.ctl.primary-btn:hover {
  background: linear-gradient(135deg, #4338ca, #4f46e5);
  box-shadow: 0 6px 18px rgba(79, 70, 229, 0.5);
}

button.ctl[aria-pressed="true"]:not(.seg) {
  background: var(--panel-border-glow);
  border-color: var(--x-color);
  color: var(--x-color);
}

/* Secondary settings sub-rows (Bot settings, Online settings) */
.sub-settings-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  padding: 12px 16px;
  background: var(--panel-sub);
  border: 1px solid var(--panel-border);
  border-radius: 16px;
}

.sub-settings-bar[hidden] {
  display: none;
}

.sub-label {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

/* Online status message */
.online-status {
  width: 100%;
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: 4px;
}

.online-status b {
  color: var(--text-primary);
  font-family: var(--font-mono);
  background: var(--panel-bg);
  padding: 3px 8px;
  border-radius: 6px;
  border: 1px solid var(--panel-border);
}

/* ==========================================================================
   ENGINE ANALYSIS PANEL
   ========================================================================== */

#panel {
  margin-top: 18px;
  padding: 20px;
  background: var(--panel-sub);
  border: 1px solid var(--panel-border);
  border-radius: 20px;
  box-shadow: var(--shadow-card);
  transition: all 0.3s ease;
}

#panel[hidden] {
  display: none;
}

.evalrow {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.evalnum {
  font-family: var(--font-display);
  font-size: 32px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

.evalmeta {
  font-size: 13px;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* Modern Chess-style Eval Bar */
.barwrap {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 12px 0 16px;
}

.barlabel {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 14px;
}

#barLabelMine { color: var(--x-color); }
#barLabelTheirs { color: var(--o-color); }

.bar {
  flex: 1;
  height: 10px;
  background: var(--o-color);
  border-radius: 999px;
  overflow: hidden;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.3);
}

.barfill {
  height: 100%;
  background: linear-gradient(90deg, var(--x-color), #6366f1);
  width: 50%;
  transition: width 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.bestline-card {
  padding: 10px 14px;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  margin-bottom: 10px;
}

.line {
  margin: 0;
  font-size: 14px;
  color: var(--text-secondary);
}

.line b {
  color: var(--text-primary);
  font-weight: 700;
  font-family: var(--font-mono);
}

.pv {
  font-size: 12px;
  font-family: var(--font-mono);
  color: var(--text-muted);
  margin-top: 4px;
}

/* Engine Alternatives List */
.alts {
  list-style: none;
  margin: 12px 0 0;
  padding: 8px 12px;
  font-size: 13px;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
}

.alts:empty {
  display: none;
}

.alts li {
  padding: 8px 4px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
}

.alts li:not(:last-child) {
  border-bottom: 1px solid var(--panel-border);
}

.alts li b {
  color: var(--x-color);
  font-weight: 700;
}

.alts .altscore {
  margin-left: auto;
  font-weight: 700;
  color: var(--text-primary);
}

/* Move Log */
.log {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  max-height: 140px;
  overflow-y: auto;
}

.log li {
  padding: 6px 4px;
  border-top: 1px solid var(--panel-border);
}

.bad { color: #ef4444; font-weight: 700; }
.mid { color: var(--accent-amber); font-weight: 700; }
.ok { color: var(--accent-green); font-weight: 700; }

/* ==========================================================================
   HOW TO PLAY MODAL & RULES ACCORDION
   ========================================================================== */

.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.modal-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-dialog {
  width: 100%;
  max-width: 580px;
  max-height: 90vh;
  background: var(--panel-bg-solid);
  border: 1px solid var(--panel-border);
  border-radius: 24px;
  padding: 28px;
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  gap: 20px;
  overflow-y: auto;
  transform: translateY(20px) scale(0.96);
  transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-backdrop.open .modal-dialog {
  transform: translateY(0) scale(1);
}

.modal-dialog.victory-dialog {
  max-width: 420px;
  text-align: center;
  align-items: center;
  padding: 36px 28px;
  background: radial-gradient(circle at 50% 10%, rgba(99, 102, 241, 0.2), transparent 70%), var(--panel-bg-solid);
}

.victory-trophy {
  font-size: 56px;
  line-height: 1;
  margin-bottom: 4px;
  animation: trophyFloat 2s infinite ease-in-out;
}

@keyframes trophyFloat {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-8px) rotate(4deg); }
}

.victory-dialog h2 {
  font-family: var(--font-display);
  font-size: 30px;
  font-weight: 800;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--text-primary), var(--accent-amber));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.victory-subtitle {
  font-size: 15px;
  color: var(--text-secondary);
  margin-top: -4px;
}

.victory-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  margin-top: 10px;
}

.victory-actions button {
  flex: 1;
  justify-content: center;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-header h2 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.rules-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}

.rule-card {
  padding: 16px;
  background: var(--panel-sub);
  border: 1px solid var(--panel-border);
  border-radius: 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.rule-number {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--x-bg);
  color: var(--x-color);
  font-family: var(--font-display);
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
}

.rule-card h3 {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-primary);
}

.rule-card p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.5;
}

.rule-note {
  padding: 14px 18px;
  background: var(--accent-green-bg);
  border-left: 4px solid var(--accent-green);
  border-radius: 12px;
  font-size: 13px;
  color: var(--text-primary);
}

/* ==========================================================================
   GAME HISTORY MODAL
   ========================================================================== */

.history-list {
  list-style: none;
  margin: 0;
  padding: 0;
  max-height: 46vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.history-list:empty::before {
  content: 'No recorded games yet — bot and online wins/losses will show up here.';
  display: block;
  padding: 18px 4px;
  font-size: 13px;
  color: var(--text-secondary);
  text-align: center;
}

.history-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border-radius: 12px;
  background: var(--panel-sub);
  border: 1px solid var(--panel-border);
  font-size: 13px;
}

.history-item.reviewable {
  cursor: pointer;
  transition: border-color 0.15s ease;
}

.history-item.reviewable:hover {
  border-color: var(--panel-border-hover);
}

.history-item .history-result {
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 11px;
}

.history-item.win .history-result {
  color: var(--accent-green);
  background: var(--accent-green-bg);
}

.history-item.loss .history-result {
  color: #ef4444;
  background: rgba(239, 68, 68, 0.14);
}

.history-item .history-opp {
  color: var(--text-primary);
  font-weight: 600;
}

.history-item .history-date {
  color: var(--text-secondary);
  font-size: 12px;
}

.history-item .history-delta {
  margin-left: auto;
  font-family: var(--font-mono);
  font-weight: 700;
}

#clearHistoryBtn.danger {
  color: #ef4444;
  border-color: #ef4444;
  background: rgba(239, 68, 68, 0.14);
}

/* ==========================================================================
   GAME REVIEW BAR
   ========================================================================== */

.review-bar {
  flex-direction: column;
  align-items: stretch;
}

.quality-badge {
  font-size: 11px;
  font-family: var(--font-mono);
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid currentColor;
  background: currentColor;
  display: inline-flex;
  align-items: center;
  animation: badgeSlideIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.quality-badge[hidden] { display: none !important; }

.quality-badge span { color: var(--panel-bg-solid); }

.quality-badge.tag-blunder { color: #ef4444; }
.quality-badge.tag-mistake { color: var(--accent-amber); }
.quality-badge.tag-inaccuracy { color: var(--accent-amber); }
.quality-badge.tag-best { color: var(--accent-green); }
.quality-badge.tag-excellent { color: var(--accent-green); }
.quality-badge.tag-great { color: var(--accent-blue); }
.quality-badge.tag-brilliant { color: var(--accent-teal); }

.review-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 10px;
}

.review-accuracy {
  display: flex;
  gap: 14px;
}

.review-accuracy-item {
  display: flex;
  align-items: baseline;
  gap: 6px;
  font-family: var(--font-mono);
}

.review-accuracy-label {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-secondary);
}

.review-accuracy-value {
  font-size: 18px;
  font-weight: 800;
  color: var(--text-primary);
}

#reviewAccX .review-accuracy-value { color: var(--x-color); }
#reviewAccO .review-accuracy-value { color: var(--o-color); }

.review-tag-counts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 10px;
}

.review-tag-counts li {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-secondary);
  white-space: nowrap;
}

.review-tag-counts li .n { font-weight: 700; }
.review-tag-counts li.tc-blunder .n { color: #ef4444; }
.review-tag-counts li.tc-mistake .n { color: var(--accent-amber); }
.review-tag-counts li.tc-inaccuracy .n { color: var(--accent-amber); }
.review-tag-counts li.tc-miss .n { color: #ef4444; }
.review-tag-counts li.tc-good .n { color: var(--text-secondary); }
.review-tag-counts li.tc-excellent .n { color: var(--accent-green); }
.review-tag-counts li.tc-best .n { color: var(--accent-green); }
.review-tag-counts li.tc-great .n { color: var(--accent-blue); }
.review-tag-counts li.tc-brilliant .n { color: var(--accent-teal); }

.review-graph-wrap {
  margin-bottom: 10px;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--panel-border);
  background: var(--panel-bg-solid);
}

.review-graph {
  display: block;
  width: 100%;
  height: 56px;
  cursor: pointer;
}

.review-graph .rg-fill-x { fill: var(--x-color); opacity: 0.28; }
.review-graph .rg-fill-o { fill: var(--o-color); opacity: 0.28; }
.review-graph .rg-line { fill: none; stroke: var(--text-secondary); stroke-width: 0.6; vector-effect: non-scaling-stroke; }
.review-graph .rg-mid { stroke: var(--panel-border); stroke-width: 0.4; vector-effect: non-scaling-stroke; }
.review-graph .rg-cursor { stroke: var(--text-primary); stroke-width: 0.6; vector-effect: non-scaling-stroke; opacity: 0.7; }
.review-graph .rg-hit { fill: transparent; }

.review-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.review-controls .icon-btn {
  width: 36px;
  height: 36px;
  font-size: 15px;
}

.review-step-label {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--text-primary);
  min-width: 64px;
  text-align: center;
}

#reviewExit {
  margin-left: 8px;
}

.review-move-list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  max-height: 120px;
  overflow-y: auto;
}

.review-move-item {
  font-family: var(--font-mono);
  font-size: 12px;
  padding: 4px 9px;
  border-radius: 8px;
  background: var(--panel-bg-solid);
  border: 1px solid var(--panel-border);
  color: var(--text-secondary);
  cursor: pointer;
}

.review-move-item:hover {
  border-color: var(--panel-border-hover);
}

.review-move-item.current {
  border-color: var(--x-color);
  color: var(--text-primary);
  background: var(--x-bg);
}

.review-move-item.tag-blunder { color: #ef4444; }
.review-move-item.tag-mistake { color: var(--accent-amber); }
.review-move-item.tag-inaccuracy { color: var(--accent-amber); }
.review-move-item.tag-best { color: var(--accent-green); }
.review-move-item.tag-excellent { color: var(--accent-green); }
.review-move-item.tag-great { color: var(--accent-blue); }
.review-move-item.tag-brilliant { color: var(--accent-teal); }

/* ==========================================================================
   TOAST NOTIFICATION
   ========================================================================== */

.toast-container {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 10001;
  pointer-events: none;
}

.toast {
  padding: 10px 20px;
  background: var(--panel-bg-solid);
  border: 1px solid var(--panel-border);
  border-radius: 999px;
  box-shadow: var(--shadow-lg);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
  opacity: 0;
  transform: translateY(10px);
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   FAQ / ABOUT SECTION
   ========================================================================== */

.faq-section {
  margin-top: 8px;
}

.faq-title {
  text-align: center;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-muted);
  margin: 0 0 14px;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */

footer {
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
  padding-top: 10px;
}

/* ==========================================================================
   RESPONSIVE LAYOUT BREAKPOINTS
   ========================================================================== */

@media (max-width: 768px) {
  .app-container {
    padding: 16px 14px 40px;
    gap: 14px;
  }

  .hud-section {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .hud-center-pill {
    order: -1;
    align-self: center;
  }

  .turn-banner {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .phase-stepper {
    width: 100%;
    justify-content: center;
  }

  .arena-card {
    padding: 16px;
    border-radius: 20px;
  }

  .primary-toolbar {
    flex-direction: column;
    align-items: stretch;
  }

  .segmented-grp {
    width: 100%;
    justify-content: center;
  }

  .action-buttons-grp {
    justify-content: center;
    width: 100%;
  }

  .rules-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .app-header {
    flex-wrap: wrap;
    padding: 12px 16px;
    gap: 10px;
  }

  .brand-badge {
    display: none;
  }

  .rating-badge {
    display: none;
  }

  .brand-title-group h1 {
    font-size: 20px;
  }

  .nav-actions {
    margin-left: auto;
    gap: 8px;
  }

  .btn-label-icon span:first-child {
    display: none;
  }

  .btn-label-icon {
    padding: 8px 12px;
  }

  .player-card {
    padding: 12px 14px;
    gap: 12px;
  }

  .player-avatar {
    width: 38px;
    height: 38px;
    font-size: 19px;
  }

  .player-name {
    font-size: 14px;
  }

  .board-viewport {
    padding: 16px 6px;
    min-height: 300px;
  }

  .sub-settings-bar .segmented-grp {
    flex-wrap: wrap;
    justify-content: center;
    border-radius: 16px;
  }

  .sub-settings-bar .segmented-grp button.ctl.seg {
    flex: 1 1 auto;
  }
}

/* Lighter backdrop-filter on mobile: blur is recomputed every scroll frame
   against whatever's now behind the element, which is a heavy per-frame
   cost on phone GPUs and was making scrolling feel laggy. */
@media (max-width: 768px) {
  .app-header,
  .player-card,
  .hud-center-pill,
  .turn-banner,
  .arena-card,
  .modal-backdrop {
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
  }
}