/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #776e65;
    font-size: 18px;
    margin: 0;
    padding: 0;
    min-height: 100vh;
    overflow-x: hidden;
}

.container {
    max-width: 500px;
    margin: 0 auto;
    padding: 20px;
    position: relative;
}

/* 头部样式 */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.title {
    font-size: 48px;
    font-weight: bold;
    color: #ffffff;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    margin: 0;
}

.score-container {
    display: flex;
    gap: 10px;
}

.score-box {
    background: rgba(255, 255, 255, 0.9);
    padding: 10px 15px;
    border-radius: 8px;
    text-align: center;
    min-width: 80px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.score-label {
    font-size: 12px;
    color: #776e65;
    text-transform: uppercase;
    font-weight: bold;
}

.score {
    font-size: 20px;
    font-weight: bold;
    color: #ffffff;
    background: linear-gradient(45deg, #ff6b6b, #ee5a24);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 游戏介绍区域 */
.game-intro {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px;
    border-radius: 12px;
    margin-bottom: 20px;
    text-align: center;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.game-explanation {
    margin-bottom: 15px;
    font-size: 16px;
    line-height: 1.5;
}

.restart-button {
    background: linear-gradient(45deg, #4ecdc4, #44a08d);
    color: white;
    padding: 12px 24px;
    border-radius: 25px;
    cursor: pointer;
    font-weight: bold;
    transition: all 0.3s ease;
    display: inline-block;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.restart-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0,0,0,0.3);
}

/* 游戏容器 */
.game-container {
    position: relative;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 12px;
    padding: 15px;
    margin-bottom: 20px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

/* 网格样式 */
.grid-container {
    position: relative;
    z-index: 1;
}

.grid-row {
    display: flex;
    margin-bottom: 8px;
}

.grid-row:last-child {
    margin-bottom: 0;
}

.grid-cell {
    width: calc(25% - 6px);
    height: 80px;
    background: rgba(238, 228, 218, 0.35);
    border-radius: 8px;
    margin-right: 8px;
    position: relative;
}

.grid-cell:last-child {
    margin-right: 0;
}

/* 数字方块容器 */
.tile-container {
    position: absolute;
    top: 15px;
    left: 15px;
    right: 15px;
    bottom: 15px;
    z-index: 2;
}

/* 数字方块样式 */
.tile {
    position: absolute;
    width: calc(25% - 6px);
    height: 80px;
    border-radius: 8px;
    font-weight: bold;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 32px;
    transition: all 0.15s ease-in-out;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

/* 不同数字的颜色 */
.tile-2 { background: #eee4da; color: #776e65; }
.tile-4 { background: #ede0c8; color: #776e65; }
.tile-8 { background: #f2b179; color: #f9f6f2; }
.tile-16 { background: #f59563; color: #f9f6f2; }
.tile-32 { background: #f67c5f; color: #f9f6f2; }
.tile-64 { background: #f65e3b; color: #f9f6f2; }
.tile-128 { background: #edcf72; color: #f9f6f2; font-size: 28px; }
.tile-256 { background: #edcc61; color: #f9f6f2; font-size: 28px; }
.tile-512 { background: #edc850; color: #f9f6f2; font-size: 28px; }
.tile-1024 { background: #edc53f; color: #f9f6f2; font-size: 24px; }
.tile-2048 { background: #edc22e; color: #f9f6f2; font-size: 24px; box-shadow: 0 0 20px rgba(237, 194, 46, 0.5); }
.tile-super { background: #3c3a32; color: #f9f6f2; font-size: 20px; }

/* 动画效果 */
.tile-new {
    animation: appear 0.2s ease-in-out;
}

.tile-merged {
    animation: pop 0.2s ease-in-out;
}

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

@keyframes pop {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.2);
    }
    100% {
        transform: scale(1);
    }
}

/* 游戏消息 */
.game-message {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.95);
    z-index: 100;
    text-align: center;
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border-radius: 12px;
}

.game-message.game-won {
    background: rgba(237, 194, 46, 0.9);
    color: #f9f6f2;
}

.game-message.game-over {
    background: rgba(238, 228, 218, 0.9);
    color: #776e65;
}

.game-message p {
    font-size: 36px;
    font-weight: bold;
    margin-bottom: 20px;
}

.lower {
    display: flex;
    gap: 15px;
}

.keep-playing-button,
.retry-button {
    background: #8f7a66;
    color: #f9f6f2;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
}

.keep-playing-button:hover,
.retry-button:hover {
    background: #9f8a76;
    transform: translateY(-2px);
}

/* 游戏统计 */
.game-stats {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px;
    border-radius: 12px;
    margin-bottom: 20px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.game-stats h3 {
    text-align: center;
    margin-bottom: 15px;
    color: #776e65;
    font-size: 20px;
}

.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 12px;
    background: rgba(238, 228, 218, 0.3);
    border-radius: 6px;
}

.stat-label {
    font-size: 14px;
    color: #776e65;
}

.stat-value {
    font-weight: bold;
    color: #f67c5f;
    font-size: 16px;
}

/* 操作提示 */
.controls-hint {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px;
    border-radius: 12px;
    text-align: center;
    font-size: 14px;
    line-height: 1.6;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.controls-hint p {
    margin-bottom: 5px;
}

.controls-hint p:last-child {
    margin-bottom: 0;
}

/* 模态框样式 */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px);
}

.modal-content {
    background-color: #fefefe;
    margin: 5% auto;
    border-radius: 15px;
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    animation: modalSlideIn 0.3s ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    padding: 20px;
    border-bottom: 1px solid #eee;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 15px 15px 0 0;
}

.modal-header h2 {
    margin: 0;
    font-size: 24px;
}

.close {
    color: white;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    transition: color 0.3s ease;
}

.close:hover {
    color: #ddd;
}

.modal-body {
    padding: 20px;
}

.final-score {
    text-align: center;
    margin-bottom: 25px;
    padding: 20px;
    background: linear-gradient(135deg, #ff9a9e 0%, #fecfef 100%);
    border-radius: 10px;
    color: white;
}

.final-score h3 {
    margin: 0;
    font-size: 28px;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.2);
}

.achievement-section h4 {
    text-align: center;
    margin-bottom: 20px;
    color: #776e65;
    font-size: 20px;
}

.achievement-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 15px;
    margin-bottom: 25px;
}

.achievement-item {
    display: flex;
    align-items: center;
    padding: 15px;
    background: linear-gradient(135deg, #a8edea 0%, #fed6e3 100%);
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

.achievement-item:hover {
    transform: translateY(-2px);
}

.achievement-icon {
    font-size: 32px;
    margin-right: 15px;
}

.achievement-info {
    flex: 1;
}

.achievement-title {
    font-size: 14px;
    color: #666;
    margin-bottom: 5px;
}

.achievement-value {
    font-size: 20px;
    font-weight: bold;
    color: #333;
}

.modal-actions {
    display: flex;
    gap: 15px;
    justify-content: center;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 25px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background: linear-gradient(45deg, #4ecdc4, #44a08d);
    color: white;
}

.btn-secondary {
    background: linear-gradient(45deg, #ff9a9e, #fecfef);
    color: white;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0,0,0,0.2);
}

/* 手机端优化 */
@media (max-width: 480px) {
    .container {
        padding: 15px;
    }
    
    .title {
        font-size: 36px;
    }
    
    .header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .score-container {
        justify-content: center;
    }
    
    .grid-cell,
    .tile {
        height: 70px;
        font-size: 28px;
    }
    
    .tile-128,
    .tile-256,
    .tile-512 {
        font-size: 24px;
    }
    
    .tile-1024,
    .tile-2048 {
        font-size: 20px;
    }
    
    .tile-super {
        font-size: 16px;
    }
    
    .game-message p {
        font-size: 28px;
    }
    
    .modal-content {
        margin: 10% auto;
        width: 95%;
    }
    
    .achievement-grid {
        grid-template-columns: 1fr;
    }
    
    .modal-actions {
        flex-direction: column;
    }
}

/* 超小屏幕优化 */
@media (max-width: 360px) {
    .grid-cell,
    .tile {
        height: 60px;
        font-size: 24px;
    }
    
    .tile-128,
    .tile-256,
    .tile-512 {
        font-size: 20px;
    }
    
    .tile-1024,
    .tile-2048 {
        font-size: 18px;
    }
    
    .tile-super {
        font-size: 14px;
    }
}

/* 电脑端优化 */
@media (min-width: 768px) {
    .container {
        padding: 30px;
    }
    
    .grid-cell,
    .tile {
        height: 90px;
        font-size: 36px;
    }
    
    .achievement-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .modal-actions {
        flex-direction: row;
    }
}

/* 触摸优化 */
@media (hover: none) and (pointer: coarse) {
    .restart-button,
    .keep-playing-button,
    .retry-button,
    .btn {
        min-height: 44px;
        min-width: 44px;
    }
}