/* ===================================
   Connect 4 - Modern Minimal Design
   =================================== */

:root {
  /* Color Palette - Subtle & Elegant */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a25;
  
  /* Accent Colors */
  --accent: #6366f1;
  --accent-light: #818cf8;
  --accent-dark: #4f46e5;
  --accent-glow: rgba(99, 102, 241, 0.3);

  --surface: rgba(255, 255, 255, 0.03);
  --surface-hover: rgba(255, 255, 255, 0.06);
  --surface-active: rgba(255, 255, 255, 0.09);

  --border: rgba(255, 255, 255, 0.08);
  --border-light: rgba(255, 255, 255, 0.12);

  --text: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  /* Game Pieces - Vibrant but refined */
  --player1: #f43f5e;
  --player1-light: #fb7185;
  --player1-glow: rgba(244, 63, 94, 0.4);
  --player1-dark: #be123c;

  --player2: #facc15;
  --player2-light: #fde047;
  --player2-glow: rgba(250, 204, 21, 0.4);
  --player2-dark: #ca8a04;

  /* Board - Deep blue refined */
  /* Board - Deep blue refined - Lighter gradient for better visibility */
  --board-bg: linear-gradient(180deg, #1e3a5f 0%, #1e3a5f 100%); /* Flat or subtle gradient */
  --board-border: rgba(255, 255, 255, 0.2);
  --cell-bg: #0f172a;
  --cell-inner: #1e293b;

  /* Status Colors */
  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
  --info: #3b82f6;

  /* Typography */
  --font-main: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 50%;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Board dimensions for calculations */
  --cell-size: 56px;
  --cell-gap: 6px;
  --board-padding: 16px;
}

/* ===================================
   Reset & Base
   =================================== */

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-main);
  background: var(--bg-primary);
  min-height: 100vh;
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

/* Subtle background pattern */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background: 
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse 60% 40% at 100% 100%, rgba(244, 63, 94, 0.05) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}

/* ===================================
   App Container
   =================================== */

.app-container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
  z-index: 1;
}

/* ===================================
   Header
   =================================== */

.header {
  padding: var(--space-md) var(--space-xl);
  background: rgba(10, 10, 15, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  justify-content: center;
}

.logo-icon {
  font-size: 1.75rem;
}

.logo h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
}

.version-badge {
  background: var(--accent);
  color: white;
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ===================================
   Main Content
   =================================== */

.main-content {
  flex: 1;
  display: grid;
  grid-template-columns: 320px 1fr 320px; /* 3 Columns Layout */
  gap: var(--space-xl);
  padding: var(--space-xl);
  max-width: 1400px; /* Increased max-width for 3 columns */
  margin: 0 auto;
  width: 100%;
  align-items: start;
}

@media (max-width: 1200px) {
  .main-content {
      grid-template-columns: 1fr;
      max-width: 800px;
  }
  
  .left-panel, .right-panel {
      width: 100%;
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: var(--space-md);
  }
}

/* ===================================
   Game Section
   =================================== */

.game-section {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
}

/* Turn Indicator */
.turn-indicator {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  background: var(--surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition-normal);
}

.turn-indicator.player1 {
  border-color: rgba(244, 63, 94, 0.3);
}

.turn-indicator.player2 {
  border-color: rgba(250, 204, 21, 0.3);
}

.player-piece {
  width: 20px;
  height: 20px;
  border-radius: var(--radius-full);
  transition: all var(--transition-normal);
}

.turn-indicator.player1 .player-piece {
  background: var(--player1);
  box-shadow: 0 0 12px var(--player1-glow);
}

.turn-indicator.player2 .player-piece {
  background: var(--player2);
  box-shadow: 0 0 12px var(--player2-glow);
}

/* Board Container */
.board-container {
  position: relative;
}

.board-glow {
  position: absolute;
  inset: -40px;
  background: radial-gradient(
    ellipse at center,
    var(--accent-glow) 0%,
    transparent 70%
  );
  opacity: 0.3;
  filter: blur(40px);
  pointer-events: none;
  z-index: -1;
}

/* Board */
.board {
  display: grid;
  grid-template-columns: repeat(7, var(--cell-size));
  grid-template-rows: repeat(6, var(--cell-size));
  gap: var(--cell-gap);
  padding: var(--board-padding);
  background: var(--board-bg);
  border-radius: var(--radius-xl);
  box-shadow: 
    0 20px 50px rgba(0, 0, 0, 0.5),
    inset 0 1px 0 rgba(255, 255, 255, 0.05);
  position: relative;
  border: 1px solid var(--board-border);
}

/* Cells */
.cell {
  width: var(--cell-size);
  height: var(--cell-size);
  border-radius: var(--radius-full);
  background: var(--cell-bg);
  position: relative;
  transition: all var(--transition-fast);
  box-shadow:
    inset 0 3px 6px rgba(0, 0, 0, 0.4),
    inset 0 -1px 2px rgba(255, 255, 255, 0.03);
}

.cell::before {
  content: "";
  position: absolute;
  inset: 3px;
  border-radius: var(--radius-full);
  transition: all var(--transition-normal);
  transform: scale(0);
}

.cell.player1::before {
  background: radial-gradient(
    circle at 35% 35%,
    var(--player1-light) 0%,
    var(--player1) 50%,
    var(--player1-dark) 100%
  );
  box-shadow:
    inset 0 -4px 12px rgba(0, 0, 0, 0.3),
    inset 0 4px 8px rgba(255, 255, 255, 0.2),
    0 4px 16px var(--player1-glow);
  transform: scale(1);
}

.cell.player2::before {
  background: radial-gradient(
    circle at 35% 35%,
    var(--player2-light) 0%,
    var(--player2) 50%,
    var(--player2-dark) 100%
  );
  box-shadow:
    inset 0 -4px 12px rgba(0, 0, 0, 0.3),
    inset 0 4px 8px rgba(255, 255, 255, 0.3),
    0 4px 16px var(--player2-glow);
  transform: scale(1);
}

.cell.dropping::before {
  animation: drop 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes drop {
  0% {
    transform: scale(1) translateY(-280px);
    opacity: 0.9;
  }
  100% {
    transform: scale(1) translateY(0);
  }
}

.cell.winning::before {
  animation: pulse 0.5s ease-in-out infinite alternate;
}

@keyframes pulse {
  from {
    filter: brightness(1);
    transform: scale(1);
  }
  to {
    filter: brightness(1.2);
    transform: scale(1.03);
  }
}

/* Column Click Areas - FIXED */
.column-areas {
  position: absolute;
  top: var(--board-padding);
  left: var(--board-padding);
  right: var(--board-padding);
  bottom: var(--board-padding);
  display: grid;
  grid-template-columns: repeat(7, var(--cell-size));
  gap: var(--cell-gap);
  pointer-events: auto;
}

.column-area {
  cursor: pointer;
  transition: background var(--transition-fast);
  border-radius: var(--radius-md);
  position: relative;
}

.column-area:hover {
  background: rgba(255, 255, 255, 0.04);
}

/* Column Hover Preview - FIXED */
.column-hover {
  display: none;
  position: absolute;
  top: -48px;
  width: var(--cell-size);
  pointer-events: none;
  z-index: 10;
}

.column-hover.visible {
  display: block;
}

.hover-piece {
  width: calc(var(--cell-size) - 8px);
  height: calc(var(--cell-size) - 8px);
  margin: 0 auto;
  border-radius: var(--radius-full);
  opacity: 0.8;
  transition: all var(--transition-fast);
}

.hover-piece.player1 {
  background: radial-gradient(
    circle at 35% 35%,
    var(--player1-light) 0%,
    var(--player1) 100%
  );
  box-shadow: 0 0 20px var(--player1-glow);
}

.hover-piece.player2 {
  background: radial-gradient(
    circle at 35% 35%,
    var(--player2-light) 0%,
    var(--player2) 100%
  );
  box-shadow: 0 0 20px var(--player2-glow);
}

/* Game Status Overlay */
.game-status {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
}

.status-content {
  text-align: center;
  padding: var(--space-2xl);
  background: rgba(10, 10, 15, 0.95);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border);
  transform: scale(0.95);
  opacity: 0;
  transition: all var(--transition-normal);
  pointer-events: none;
}

.status-content.visible {
  transform: scale(1);
  opacity: 1;
  pointer-events: auto;
}

.status-content.hidden {
  display: none;
}

.winner-icon {
  font-size: 3.5rem;
  margin-bottom: var(--space-md);
  animation: float 2s ease-in-out infinite;
}

@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-8px);
  }
}

.status-content h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--space-lg);
  color: var(--text);
}

/* ===================================
   Controls Panel
   =================================== */

/* ===================================
   Panels (Left & Right)
   =================================== */

.left-panel,
.right-panel {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  width: 100%;
}

.panel-section {
  background: var(--surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  border: 1px solid var(--border);
}

.panel-section h3 {
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--text);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* Control Groups */
.control-group {
  margin-bottom: var(--space-lg);
}

.control-group:last-child {
  margin-bottom: 0;
}

.control-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 500;
  margin-bottom: var(--space-sm);
  color: var(--text-secondary);
}

.control-hint {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
  line-height: 1.4;
}

/* Text Input */
.text-input {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font-main);
  font-size: 0.875rem;
  outline: none;
  transition: all var(--transition-fast);
}

.text-input::placeholder {
  color: var(--text-muted);
}

.text-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

/* Slider */
.slider-container {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

input[type="range"] {
  flex: 1;
  height: 4px;
  border-radius: 2px;
  background: var(--border);
  outline: none;
  -webkit-appearance: none;
  appearance: none;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: var(--radius-full);
  background: var(--accent);
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  transition: all var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
  background: var(--accent-light);
}

.slider-value {
  min-width: 28px;
  text-align: center;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent-light);
}

/* Toggle Switch */
.toggle-switch {
  position: relative;
  display: inline-block;
  width: 44px;
  height: 24px;
  cursor: pointer;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-slider {
  position: absolute;
  inset: 0;
  background: var(--border);
  border-radius: 24px;
  transition: all var(--transition-fast);
}

.toggle-slider::before {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  left: 3px;
  bottom: 3px;
  background: white;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.toggle-switch input:checked + .toggle-slider {
  background: var(--accent);
}

.toggle-switch input:checked + .toggle-slider::before {
  transform: translateX(20px);
}

/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-sm);
}

.stat-item {
  background: var(--bg-secondary);
  border-radius: var(--radius-sm);
  padding: var(--space-sm);
  text-align: center;
}

.stat-label {
  display: block;
  font-size: 0.65rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 2px;
}

.stat-value {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent-light);
}

/* Column Scores */
.column-scores-section {
  width: 100%;
  max-width: calc(7 * var(--cell-size) + 6 * var(--cell-gap) + 2 * var(--board-padding)); /* Match board width */
  margin-top: var(--space-md);
  padding: var(--space-md) !important;
  background: transparent !important;
  border: none !important;
}

.column-scores-section h3 {
  justify-content: center;
  opacity: 0.7;
}

.column-scores {
  display: grid;
  grid-template-columns: repeat(7, 1fr); /* Align exactly with board columns */
  gap: var(--cell-gap);
  padding: 0 var(--board-padding); /* Match board padding */
}

.score-bar {
  display: flex; /* Changed from flex:1 to fit grid */
  width: 100%;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: var(--space-xs);
  background: var(--bg-secondary);
  border-radius: var(--radius-sm);
  font-size: 0.7rem;
  font-weight: 600;
  min-height: 36px;
  justify-content: flex-end;
  transition: all var(--transition-fast);
  color: var(--text-muted);
}

.score-bar.positive {
  background: linear-gradient(
    180deg,
    rgba(34, 197, 94, 0.2) 0%,
    var(--bg-secondary) 100%
  );
  color: var(--success);
}

.score-bar.negative {
  background: linear-gradient(
    180deg,
    rgba(239, 68, 68, 0.2) 0%,
    var(--bg-secondary) 100%
  );
  color: var(--danger);
}

.score-bar.best {
  background: linear-gradient(
    180deg,
    rgba(250, 204, 21, 0.25) 0%,
    var(--bg-secondary) 100%
  );
  color: var(--player2);
  box-shadow: 0 0 8px rgba(250, 204, 21, 0.2);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-main);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  width: 100%;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: white;
  box-shadow: 0 2px 8px var(--accent-glow);
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-light);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--surface);
  color: var(--text-secondary);
  border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--surface-hover);
  color: var(--text);
}

.btn-danger {
  background: var(--danger);
  color: white;
}

.btn-danger:hover:not(:disabled) {
  background: #dc2626;
  transform: translateY(-1px);
}

.actions {
  display: flex;
  gap: var(--space-sm);
}

.actions .btn {
  flex: 1;
}

/* ===================================
   Footer
   =================================== */

.footer {
  text-align: center;
  padding: var(--space-md);
  color: var(--text-muted);
  font-size: 0.7rem;
  border-top: 1px solid var(--border);
  background: rgba(10, 10, 15, 0.5);
}

/* ===================================
   Thinking Indicator
   =================================== */

.thinking-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(8px);
  border-radius: var(--radius-xl);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
}

.thinking-overlay.visible {
  opacity: 1;
  pointer-events: auto;
}

.thinking-spinner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-md);
}

.spinner {
  width: 40px;
  height: 40px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: var(--radius-full);
  animation: spin 0.7s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.thinking-text {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
}

/* ===================================
   Leaderboard
   =================================== */

.leaderboard-section {
  margin-top: 0;
}

.leaderboard-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
}

.leaderboard-header h3 {
  margin-bottom: 0;
}

.leaderboard-clear-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 0.65rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.leaderboard-clear-btn:hover {
  background: var(--danger);
  color: white;
  border-color: var(--danger);
}

.leaderboard-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  max-height: 180px;
  overflow-y: auto;
}

.leaderboard-empty {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.75rem;
  padding: var(--space-lg);
  font-style: italic;
}

.leaderboard-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm);
  background: var(--bg-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  animation: slideIn 0.25s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(-8px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.leaderboard-item:hover {
  background: var(--surface-hover);
}

.leaderboard-rank {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 0.7rem;
  background: var(--border);
  color: var(--text-muted);
  flex-shrink: 0;
}

.leaderboard-rank.gold {
  background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
  color: #1a1a2e;
  box-shadow: 0 2px 8px rgba(251, 191, 36, 0.3);
}

.leaderboard-rank.silver {
  background: linear-gradient(135deg, #d1d5db 0%, #9ca3af 100%);
  color: #1a1a2e;
}

.leaderboard-rank.bronze {
  background: linear-gradient(135deg, #d97706 0%, #b45309 100%);
  color: #fff;
}

.leaderboard-info {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.leaderboard-depth {
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.leaderboard-date {
  font-size: 0.65rem;
  color: var(--text-muted);
}

.leaderboard-badge {
  padding: 3px 6px;
  border-radius: 4px;
  font-size: 0.55rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  flex-shrink: 0;
}

.leaderboard-badge.legendary {
  background: linear-gradient(135deg, #f43f5e 0%, #fbbf24 50%, #22c55e 100%);
  color: #1a1a2e;
  animation: shimmer 2s ease-in-out infinite;
}

.leaderboard-badge.master {
  background: var(--accent);
  color: white;
}

.leaderboard-badge.expert {
  background: var(--success);
  color: #1a1a2e;
}

.leaderboard-badge.intermediate {
  background: var(--info);
  color: #1a1a2e;
}

.leaderboard-badge.beginner {
  background: var(--border);
  color: var(--text);
}

@keyframes shimmer {
  0%, 100% {
    filter: brightness(1);
  }
  50% {
    filter: brightness(1.15);
  }
}

.leaderboard-list::-webkit-scrollbar {
  width: 3px;
}

.leaderboard-list::-webkit-scrollbar-track {
  background: transparent;
}

.leaderboard-list::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

.leaderboard-list::-webkit-scrollbar-thumb:hover {
  background: var(--border-light);
}

/* ===================================
   Responsive Design
   =================================== */

@media (max-width: 1000px) {
  .main-content {
    flex-direction: column;
    align-items: center;
  }

  .controls-panel {
    width: 100%;
    max-width: 450px;
  }
}

@media (max-width: 550px) {
  :root {
    --cell-size: 42px;
    --cell-gap: 4px;
    --board-padding: 12px;
  }

  .header {
    padding: var(--space-sm) var(--space-md);
  }

  .main-content {
    padding: var(--space-md);
  }

  .logo h1 {
    font-size: 1.25rem;
  }

  .logo-icon {
    font-size: 1.5rem;
  }

  .panel-section {
    padding: var(--space-md);
  }

  .column-hover {
    top: -40px;
  }
}