*, *::before, *::after { box-sizing: border-box; }
:root {
  --primary: #4361ee;
  --primary-light: #4895ef;
  --primary-dark: #3551d1;
  --secondary: #3a0ca3;
  --accent: #f72585;
  --success: #4cc9f0;
  --warning: #f8961e;
  --danger: #f94144;
  --light: #f8f9fa;
  --dark: #212529;
  --board-bg: #f3d5b5;
  --board-lines: #7f5539;
  --black-piece: #0a0a0a;
  --white-piece: #f0f0f0;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow-sm: 0 2px 4px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 8px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 16px rgba(0,0,0,0.16);
  --font-main: 'Segoe UI', 'Microsoft YaHei', sans-serif;
  --transition-fast: all 0.2s ease;
  --transition-normal: all 0.3s ease;
}

body { 
  margin: 0; 
  font-family: var(--font-main); 
  background-color: #f0f2f5; 
  color: var(--dark); 
  line-height: 1.6;
  min-height: 100vh;
}

.app-container { 
  max-width: 1200px; 
  margin: 0 auto; 
  padding: 10px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden; /* 防止水平溢出 */
}

header { 
  text-align: center; 
  padding: 15px; 
  margin-bottom: 20px; 
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white; 
  border-radius: var(--radius-md); 
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

header::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255,255,255,0.1) 10%, transparent 60%);
  z-index: 0;
  animation: rotateGradient 20s linear infinite;
}

@keyframes rotateGradient {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

header h1 { 
  margin: 0; 
  font-size: 28px; 
  position: relative;
  z-index: 1;
  text-shadow: 1px 1px 2px rgba(0,0,0,0.3);
  font-weight: 700;
  letter-spacing: 1px;
}

/* Fixed fullscreen button */
#fullScreenButton {
  position: fixed;
  top: 15px;
  right: 15px;
  z-index: 1000;
  background: var(--primary);
  color: white;
  border: none;
  padding: 6px 10px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: var(--transition-normal);
  font-family: var(--font-main);
  font-weight: 600;
  font-size: 13px;
  display: flex;
  align-items: center;
  gap: 4px;
}

#fullScreenButton::before {
  content: "⛶";
  font-size: 15px;
}

#fullScreenButton:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* Main content layout */
.main-content { 
  display: flex; 
  flex-direction: row; 
  gap: 20px;
  flex: 1;
}

.left-panel { 
  flex: 3; 
  display: flex; 
  flex-direction: column; 
  align-items: center;
}

.right-panel { 
  flex: 2; 
  display: flex; 
  flex-direction: column; 
  gap: 15px;
}

.panel-card {
  background: white;
  border-radius: var(--radius-md);
  padding: 15px;
  box-shadow: var(--shadow-md);
  transition: var(--transition-fast);
  border: 1px solid rgba(0,0,0,0.05);
}

.panel-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

/* Common section styles */
.scoreboard, .timer { 
  display: flex; 
  justify-content: center; 
  align-items: center; 
  gap: 10px; 
  font-size: 15px;
}

.scoreboard { 
  flex-wrap: wrap; 
  padding: 10px;
}

.score-box { 
  display: flex; 
  align-items: center; 
  gap: 8px; 
  background: var(--light); 
  padding: 8px 14px; 
  border-radius: 20px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-fast);
  border: 1px solid rgba(0,0,0,0.05);
}

.score-box:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.score-label {
  color: var(--dark);
  font-weight: 600;
}

.player-score, .computer-score { 
  font-weight: bold; 
  font-size: 18px;
  min-width: 28px;
  text-align: center;
  text-shadow: 0 1px 1px rgba(0,0,0,0.1);
}

.player-score {
  color: var(--primary);
  background: rgba(67, 97, 238, 0.1);
  padding: 2px 6px;
  border-radius: 10px;
}

.computer-score {
  color: var(--secondary);
  background: rgba(58, 12, 163, 0.1);
  padding: 2px 6px;
  border-radius: 10px;
}

.controls-container { 
  display: flex; 
  flex-direction: column; 
  gap: 8px;
}

.controls, .extra-controls { 
  display: flex; 
  flex-wrap: wrap; 
  justify-content: center; 
  gap: 4px;
}

/* Buttons and selects */
button, select { 
  background: var(--primary); 
  color: white; 
  border: none; 
  padding: 7px 12px; 
  border-radius: 20px; 
  font-size: 14px; 
  cursor: pointer; 
  transition: var(--transition-normal); 
  box-shadow: var(--shadow-sm);
  font-family: var(--font-main);
  font-weight: 600;
  outline: none;
  min-width: 80px;
  text-align: center;
  letter-spacing: 0.5px;
}

button:hover { 
  background: var(--primary-dark); 
  transform: translateY(-2px); 
  box-shadow: var(--shadow-md);
}

button:active { 
  transform: translateY(-1px);
}

select { 
  background-color: white; 
  color: var(--dark); 
  border: 1px solid #ddd;
  padding-right: 30px;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23333' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 10px center;
  background-size: 14px;
}

select:hover {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.1);
  transform: translateY(-2px);
}

#resetScore { 
  background-color: var(--danger);
}

#resetScore:hover { 
  background-color: #e41b23;
}

#undo { 
  background-color: var(--warning);
}

#undo:hover { 
  background-color: #e67e22;
}

#saveGame, #loadGame, #replayGame {
  background-color: var(--success);
}

#saveGame:hover, #loadGame:hover, #replayGame:hover {
  background-color: #3db4ed;
}

#toggleSound {
  background-color: var(--secondary);
}

#toggleSound:hover {
  background-color: #2c0a7a;
}

/* Status container */
#statusContainer { 
  display: flex; 
  justify-content: center; 
  align-items: center; 
  gap: 8px; 
  background: var(--light); 
  padding: 12px; 
  border-radius: var(--radius-md); 
  font-size: 15px;
  margin: 8px 0;
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
  min-height: 50px;
  border-left: 4px solid var(--primary);
}

#statusText {
  font-weight: 600;
  color: var(--dark);
}

#spinner { 
  animation: spin 1s linear infinite;
  font-size: 18px;
}

@keyframes spin { 
  0% { transform: rotate(0deg); } 
  100% { transform: rotate(360deg); }
}

/* Board container */
.board-container { 
  display: flex; 
  justify-content: center; 
  align-items: center; 
  margin: 10px auto;
  position: relative;
  padding: 0;
  width: 100%;
  max-width: 500px;
  max-height: 80vh; /* 限制最大高度，避免超出屏幕 */
  aspect-ratio: 1/1;
  touch-action: manipulation; /* 防止浏览器默认的缩放和滚动行为 */
}

canvas { 
  width: 100%;
  height: 100%;
  border-radius: var(--radius-lg); 
  box-shadow: var(--shadow-lg);
  background-color: var(--board-bg);
  transition: var(--transition-normal);
  border: 1px solid #e0c9a6;
  image-rendering: crisp-edges;
  image-rendering: -webkit-optimize-contrast;
  image-rendering: pixelated; /* For Firefox */
  -ms-interpolation-mode: nearest-neighbor; /* For IE */
  touch-action: none; /* 防止Canvas上的触摸手势被浏览器解释 */
}

canvas:hover {
  transform: scale(1.01);
  box-shadow: 0 12px 24px rgba(0,0,0,0.2);
}

.timer {
  background: linear-gradient(to right, rgba(67, 97, 238, 0.05), rgba(76, 201, 240, 0.1));
  padding: 8px 15px;
  border-radius: 20px;
  margin-top: 10px;
  font-weight: 600;
  display: inline-flex;
  box-shadow: var(--shadow-sm);
  color: var(--dark);
  border: 1px solid rgba(67, 97, 238, 0.1);
}

/* Log and stats containers */
.log-stats { 
  display: flex; 
  flex-wrap: wrap; 
  gap: 15px;
}

.log-container, .stats { 
  flex: 1; 
  min-width: 240px; 
  background: white; 
  border-radius: var(--radius-md); 
  box-shadow: var(--shadow-md); 
  padding: 15px; 
  height: 200px; 
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--primary-light) transparent;
  border: 1px solid rgba(0,0,0,0.05);
  transition: var(--transition-fast);
}

.log-container:hover, .stats:hover {
  box-shadow: var(--shadow-lg);
}

.log-container::-webkit-scrollbar, .stats::-webkit-scrollbar {
  width: 5px;
}

.log-container::-webkit-scrollbar-thumb, .stats::-webkit-scrollbar-thumb {
  background-color: var(--primary-light);
  border-radius: 3px;
}

.log-container h2, .stats h2 { 
  font-size: 18px; 
  color: var(--primary); 
  margin: 0 0 12px 0; 
  padding-bottom: 8px; 
  border-bottom: 2px solid rgba(67, 97, 238, 0.2);
  font-weight: 700;
  position: sticky;
  top: 0;
  background: white;
  z-index: 1;
}

.log-entry { 
  font-size: 13px; 
  margin: 5px 0; 
  padding: 6px 8px; 
  border-radius: var(--radius-sm);
  transition: var(--transition-fast);
  border-left: 3px solid transparent;
  line-height: 1.4;
}

.log-entry:hover {
  background-color: rgba(67, 97, 238, 0.05);
  border-left-color: var(--primary);
}

.stats p { 
  display: flex; 
  justify-content: space-between; 
  margin: 10px 0; 
  font-size: 14px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  background-color: var(--light);
  transition: var(--transition-fast);
  border-left: 3px solid transparent;
}

.stats p:hover {
  background-color: rgba(67, 97, 238, 0.05);
  border-left-color: var(--primary);
  transform: translateX(2px);
}

.stats span {
  font-weight: 600;
  color: var(--primary);
  background: rgba(67, 97, 238, 0.1);
  padding: 1px 6px;
  border-radius: 10px;
}

/* Responsive design */
/* 针对不同屏幕尺寸的优化 */
@media (max-width: 768px) {
  .app-container { 
    padding: 5px;
  }
  
  header {
    padding: 10px;
    margin-bottom: 10px;
  }
  
  header h1 {
    font-size: 18px;
  }
  
  .main-content { 
    flex-direction: column;
    gap: 10px;
  }
  
  .panel-card {
    padding: 10px;
    margin-bottom: 5px;
  }
  
  .scoreboard { 
    flex-wrap: wrap;
    padding: 5px;
  }
  
  .controls, .extra-controls { 
    flex-wrap: wrap;
    gap: 5px;
  }
  
  button, select { 
    flex-grow: 1; 
    font-size: 12px; 
    padding: 8px 10px; /* 增加点击区域 */
    min-width: 70px;
  }
  
  .log-container, .stats { 
    min-width: 100%; 
    height: 120px;
    padding: 10px;
    margin-top: 5px;
  }
  
  .log-container h2, .stats h2 {
    font-size: 16px;
    margin: 0 0 8px 0;
  }
  
  .timer {
    font-size: 12px;
    padding: 5px 8px;
    margin-top: 5px;
  }
  
  #fullScreenButton {
    top: 5px;
    right: 5px;
    padding: 5px 8px;
    font-size: 11px;
  }
  
  .board-container {
    max-width: calc(100vw - 20px); /* 确保不超出屏幕 */
    max-height: 60vh; /* 在竖屏设备上限制高度 */
    margin: 5px auto;
  }
  
  /* 确保棋盘在手机上显示得足够大 */
  canvas {
    border-radius: var(--radius-sm); /* 减小圆角使视觉上更大 */
    box-shadow: var(--shadow-md); /* 减小阴影 */
  }
  
  /* 增强移动设备的可点击区域 */
  .score-box {
    padding: 6px 10px; /* 减小填充 */
    font-size: 12px;
  }
  
  .score-label {
    font-size: 12px;
  }
  
  .player-score, .computer-score {
    font-size: 14px;
    min-width: 20px;
  }
}

/* 特别小的屏幕优化 */
@media (max-width: 360px) {
  header h1 {
    font-size: 16px;
  }
  
  button, select {
    font-size: 11px;
    padding: 6px 8px;
    min-width: 60px;
  }
  
  .board-container {
    max-height: 50vh;
  }
  
  .log-container, .stats {
    height: 100px;
  }
}

@media (min-width: 769px) and (max-width: 1100px) {
  .board-container {
    max-width: 450px;
    max-height: 70vh;
  }
  
  .app-container {
    padding: 12px;
  }
  
  .main-content {
    gap: 15px;
  }
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideUp {
  from { transform: translateY(20px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

.board-container {
  animation: slideUp 0.6s ease-out forwards;
}

.scoreboard, .controls-container {
  animation: slideUp 0.7s ease-out forwards;
}

.log-stats {
  animation: slideUp 0.8s ease-out forwards;
}

header {
  animation: fadeIn 0.9s ease-out forwards;
}

/* Piece animations */
@keyframes piecePop {
  0% { transform: scale(0.5); opacity: 0.5; }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); opacity: 1; }
}

/* Win line effect */
@keyframes winLineFlash {
  0% { opacity: 0.3; }
  50% { opacity: 1; }
  100% { opacity: 0.3; }
}

/* New styling elements */
.tooltip {
  position: absolute;
  background: rgba(0, 0, 0, 0.8);
  color: white;
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 12px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.3s;
  z-index: 1000;
}

button:focus, select:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.3);
}

/* Button icon styles */
.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-right: 4px;
  font-size: 14px;
}