/* 重置样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

/* 根变量定义 - 简化配色方案 */
:root {
    --primary-color: #4285f4;
    --primary-light: #6fa8f5;
    --primary-dark: #1a73e8;
    --secondary-color: #34a853;
    --warning-color: #fbbc04;
    --error-color: #ea4335;
    --background-color: #f8f9fa;
    --card-background: #ffffff;
    --text-primary: #202124;
    --text-secondary: #5f6368;
    --border-color: #dadce0;
    --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.12);
    --shadow-medium: 0 4px 8px rgba(0, 0, 0, 0.12);
    --shadow-heavy: 0 8px 16px rgba(0, 0, 0, 0.15);
    --border-radius: 12px;
    --border-radius-small: 6px;
    --transition: all 0.2s ease;
}

/* 暗色主题变量 */
.dark-theme {
    --background-color: #202124;
    --card-background: #303134;
    --text-primary: #e8eaed;
    --text-secondary: #9aa0a6;
    --border-color: #5f6368;
    --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-medium: 0 4px 8px rgba(0, 0, 0, 0.3);
    --shadow-heavy: 0 8px 16px rgba(0, 0, 0, 0.4);
}

/* 主体样式 */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    transition: var(--transition);
    position: relative;
}

/* 主容器 */
.container {
    background: var(--card-background);
    padding: 32px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
    text-align: center;
    width: 100%;
    max-width: min(95vw, 1000px);
    margin: 0 auto;
    transition: var(--transition);
    position: relative;
}

/* 标题样式 */
h1 {
    color: var(--text-primary);
    margin-bottom: 32px;
    font-size: clamp(28px, 6vw, 36px);
    font-weight: 500;
    letter-spacing: -0.5px;
    transition: var(--transition);
}

/* 主游戏区域 - 新的布局结构 */
.game-area {
    display: flex;
    flex-direction: row;
    align-items: flex-start;
    justify-content: center;
    gap: 40px;
    margin: 0 auto;
    width: 100%;
}

/* 棋盘包装器 */
.board-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex: 0 0 auto;
}

/* 数独棋盘 */
#board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    grid-template-rows: repeat(9, 1fr);
    gap: 1px;
    border: 2px solid var(--text-primary);
    border-radius: var(--border-radius-small);
    touch-action: manipulation;
    aspect-ratio: 1/1;
    width: min(65vw, 65vh, 500px);
    background: var(--text-primary);
    box-shadow: var(--shadow-medium);
    overflow: hidden;
}

/* 右侧控制面板 */
.right-panel {
    display: flex;
    flex-direction: column;
    gap: 20px;
    flex: 0 0 auto;
    width: 240px;
    align-items: stretch;
    justify-content: flex-start;
}

/* 游戏控制区域 - 移到右侧面板 */
.game-controls {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 16px;
    background: var(--card-background);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-light);
}

.game-controls h3 {
    color: var(--text-primary);
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 6px;
    text-align: left;
}

/* 按钮基础样式 */
button, select {
    padding: 10px 14px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-small);
    cursor: pointer;
    font-size: 13px;
    font-weight: 500;
    transition: var(--transition);
    background: var(--card-background);
    color: var(--text-primary);
    width: 100%;
}

/* 主要按钮样式 */
button {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

button:hover {
    background: var(--primary-dark);
    border-color: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-light);
}

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

/* 特殊按钮样式 */
#new-game {
    background: var(--secondary-color);
    border-color: var(--secondary-color);
}

#new-game:hover {
    background: #2d8f47;
    border-color: #2d8f47;
}

#check-solution {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

#solve {
    background: var(--warning-color);
    border-color: var(--warning-color);
    color: var(--text-primary);
}

#solve:hover {
    background: #f9ab00;
    border-color: #f9ab00;
}

#hint {
    background: var(--card-background);
    color: var(--primary-color);
    border-color: var(--primary-color);
}

#hint:hover {
    background: var(--primary-color);
    color: white;
}

/* 选择框样式 */
select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3e%3c/svg%3e");
    background-position: right 12px center;
    background-repeat: no-repeat;
    background-size: 16px;
    padding-right: 40px;
}

select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(66, 133, 244, 0.2);
}

/* 单元格样式 */
.cell {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: var(--card-background);
    font-size: clamp(18px, 4vw, 24px);
    font-weight: 500;
    cursor: pointer;
    touch-action: manipulation;
    aspect-ratio: 1/1;
    transition: var(--transition);
    color: var(--text-primary);
    position: relative;
}

.cell:hover {
    background: #e8f0fe;
}

.cell.given {
    font-weight: 600;
    background: #f8f9fa;
    color: var(--text-primary);
}

.cell.selected {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 0 0 2px rgba(66, 133, 244, 0.3);
}

.cell.error {
    background: #fce8e6;
    color: var(--error-color);
    animation: shake 0.3s ease-in-out;
}

.cell.hint {
    color: var(--secondary-color);
    font-weight: 600;
}

.cell.hint-highlight {
    animation: hint-pulse 1s ease;
}

/* 动画效果 */
@keyframes hint-pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); background: #e6f4ea; }
    100% { transform: scale(1); }
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-3px); }
    75% { transform: translateX(3px); }
}

/* 3x3宫格分隔线 */
.cell:nth-child(3n):not(:nth-child(9n)) {
    border-right: 2px solid var(--text-primary);
}

.cell:nth-child(n+19):nth-child(-n+27),
.cell:nth-child(n+46):nth-child(-n+54) {
    border-bottom: 2px solid var(--text-primary);
}

/* 数字键盘 - 重新设计 */
.mobile-numpad {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    padding: 16px;
    background: var(--card-background);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-light);
}

.mobile-numpad h3 {
    grid-column: 1 / -1;
    color: var(--text-primary);
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 6px;
    text-align: left;
}

.num-button {
    width: 55px;
    height: 55px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-small);
    background: var(--card-background);
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    justify-self: center;
}

.num-button:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    transform: translateY(-1px);
    box-shadow: var(--shadow-light);
}

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

/* 删除按钮 - 重新设计 */
.num-button.delete {
    grid-column: 1 / -1;
    width: 100%;
    height: 45px;
    background: var(--card-background);
    color: var(--error-color);
    border-color: var(--error-color);
    font-size: 13px;
    font-weight: 500;
    margin-top: 6px;
}

.num-button.delete:hover {
    background: var(--error-color);
    color: white;
    border-color: var(--error-color);
}

/* 主题切换按钮 */
#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--card-background);
    border: 1px solid var(--border-color);
    cursor: pointer;
    font-size: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    box-shadow: var(--shadow-light);
    z-index: 1000;
    min-width: auto;
    padding: 0;
}

#theme-toggle:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* 计时器和消息 */
#timer, #message {
    margin-top: 20px;
    font-size: 16px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
}

#timer {
    background: var(--card-background);
    padding: 8px 16px;
    border-radius: var(--border-radius-small);
    border: 1px solid var(--border-color);
    display: inline-block;
}

#message {
    color: var(--secondary-color);
    font-weight: 600;
    padding: 12px;
    border-radius: var(--border-radius-small);
    background: #e6f4ea;
    border: 1px solid #ceead6;
    margin-top: 16px;
}

#message.error {
    color: var(--error-color);
    background: #fce8e6;
    border-color: #f6aea9;
}

/* 小屏幕优化 - 垂直布局 */
@media (max-width: 767px) {
    body {
        padding: 16px;
    }
    
    .container {
        padding: 20px;
    }
    
    h1 {
        margin-bottom: 20px;
        font-size: 24px;
    }
    
    .game-area {
        flex-direction: column;
        gap: 20px;
        align-items: center;
    }
    
    .right-panel {
        width: 100%;
        max-width: 300px;
    }
    
    #board {
        width: min(90vw, 90vh, 350px);
    }
    
    .game-controls {
        padding: 16px;
    }
    
    .mobile-numpad {
        padding: 16px;
        gap: 8px;
    }
    
    .num-button {
        width: 50px;
        height: 50px;
        font-size: 16px;
    }
    
    .num-button.delete {
        height: 45px;
    }
    
    #theme-toggle {
        top: 16px;
        right: 16px;
        width: 40px;
        height: 40px;
        font-size: 16px;
    }
}

/* 中等屏幕优化 */
@media (min-width: 768px) and (max-width: 1024px) {
    .container {
        max-width: 95vw;
        padding: 28px;
    }
    
    .game-area {
        gap: 25px;
    }
    
    .right-panel {
        width: 200px;
        gap: 16px;
    }
    
    #board {
        width: min(60vw, 60vh, 450px);
    }
    
    .game-controls {
        padding: 14px;
        gap: 8px;
    }
    
    .mobile-numpad {
        padding: 14px;
        gap: 6px;
    }
    
    .num-button {
        width: 50px;
        height: 50px;
        font-size: 15px;
    }
    
    .num-button.delete {
        height: 40px;
    }
}

/* 大屏幕优化 */
@media (min-width: 1025px) {
    .container {
        max-width: 1100px;
        padding: 40px;
    }
    
    .game-area {
        gap: 40px;
    }
    
    .right-panel {
        width: 250px;
        gap: 18px;
    }
    
    #board {
        width: 500px;
    }
    
    .game-controls {
        padding: 18px;
        gap: 12px;
    }
    
    .mobile-numpad {
        padding: 18px;
        gap: 10px;
    }
    
    .num-button {
        width: 60px;
        height: 60px;
        font-size: 18px;
    }
    
    .num-button.delete {
        height: 50px;
    }
}

/* 横屏模式优化 */
@media (orientation: landscape) and (max-height: 600px) {
    body {
        align-items: flex-start;
        padding: 10px;
    }
    
    .container {
        padding: 16px;
        margin-top: 10px;
    }
    
    h1 {
        font-size: 18px;
        margin-bottom: 12px;
    }
    
    .game-area {
        gap: 20px;
    }
    
    .right-panel {
        width: 180px;
    }
    
    #board {
        width: min(45vw, 70vh, 300px);
    }
    
    .game-controls {
        padding: 12px;
    }
    
    .mobile-numpad {
        padding: 12px;
        gap: 6px;
    }
    
    .num-button {
        width: 45px;
        height: 45px;
        font-size: 14px;
    }
    
    .num-button.delete {
        height: 40px;
        font-size: 12px;
    }
    
    #timer, #message {
        margin-top: 10px;
        font-size: 13px;
    }
}

/* 焦点样式 */
button:focus,
select:focus,
.cell:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(66, 133, 244, 0.2);
}

/* 禁用状态 */
button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none !important;
}

button:disabled:hover {
    transform: none;
    background: var(--primary-color);
}

/* 选择文本样式 */
::selection {
    background: rgba(66, 133, 244, 0.2);
    color: var(--text-primary);
}

::-moz-selection {
    background: rgba(66, 133, 244, 0.2);
    color: var(--text-primary);
}