/* 全局样式 */
html, body {
    margin: 0;
    padding: 0;
    background: #faf8ef;
    color: #776e65;
    font-family: "Clear Sans", "Helvetica Neue", Arial, sans-serif;
    font-size: 18px;
}

body {
    margin: 20px 0;
}

/* 容器 */
.container {
    width: 500px;
    margin: 0 auto;
}

/* 标题区域 */
.heading {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.title {
    font-size: 80px;
    font-weight: bold;
    margin: 0;
    display: block;
    color: #776e65;
}

/* 分数容器 */
.scores-container {
    display: flex;
    gap: 10px;
}

.score-container, .best-container {
    position: relative;
    background: #bbada0;
    padding: 15px 25px;
    font-size: 13px;
    border-radius: 3px;
    color: white;
    text-align: center;
    min-width: 50px;
}

.score-label, .best-label {
    text-transform: uppercase;
    font-size: 13px;
    margin-bottom: 5px;
}

.score, .best {
    font-size: 25px;
    font-weight: bold;
}

/* 分数增加动画 */
.score-addition {
    position: absolute;
    right: 30px;
    color: rgba(119, 110, 101, 0.9);
    font-size: 25px;
    line-height: 25px;
    font-weight: bold;
    animation: move-up 600ms ease-in;
    animation-fill-mode: both;
}

@keyframes move-up {
    0% {
        top: 25px;
        opacity: 1;
    }
    100% {
        top: -50px;
        opacity: 0;
    }
}

/* 游戏介绍和按钮 */
.above-game {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.game-intro {
    margin: 0;
    line-height: 1.65;
}

.restart-button {
    background: #8f7a66;
    border-radius: 3px;
    padding: 10px 20px;
    color: #f9f6f2;
    text-decoration: none;
    font-weight: bold;
    border: none;
    cursor: pointer;
    font-size: 18px;
    transition: background 0.3s;
}

.restart-button:hover {
    background: #9f8a76;
}

/* 游戏容器 */
.game-container {
    margin-top: 40px;
    position: relative;
    padding: 15px;
    background: #bbada0;
    border-radius: 6px;
    width: 500px;
    height: 500px;
    box-sizing: border-box;
}

/* 游戏消息 */
.game-message {
    display: none;
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background: rgba(238, 228, 218, 0.73);
    z-index: 100;
    text-align: center;
    animation: fade-in 800ms ease;
    animation-fill-mode: both;
    border-radius: 6px;
}

.game-message p {
    font-size: 60px;
    font-weight: bold;
    height: 60px;
    line-height: 60px;
    margin-top: 222px;
}

.game-message.game-won {
    background: rgba(237, 194, 46, 0.5);
    color: #f9f6f2;
    display: block;
}

.game-message.game-over {
    background: rgba(238, 228, 218, 0.73);
    display: block;
}

.game-message .lower {
    display: block;
    margin-top: 59px;
}

.retry-button, .keep-playing-button {
    background: #8f7a66;
    border-radius: 3px;
    padding: 10px 20px;
    color: #f9f6f2;
    text-decoration: none;
    font-weight: bold;
    border: none;
    cursor: pointer;
    font-size: 18px;
    margin: 0 10px;
    transition: background 0.3s;
}

.retry-button:hover, .keep-playing-button:hover {
    background: #9f8a76;
}

@keyframes fade-in {
    0% {
        opacity: 0;
    }
    100% {
        opacity: 1;
    }
}

/* 网格容器 */
.grid-container {
    position: absolute;
    z-index: 1;
}

.grid-row {
    margin-bottom: 15px;
}

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

.grid-row:after {
    content: "";
    display: block;
    clear: both;
}

.grid-cell {
    width: 106.25px;
    height: 106.25px;
    margin-right: 15px;
    float: left;
    border-radius: 3px;
    background: rgba(238, 228, 218, 0.35);
}

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

/* 方块容器 */
.tile-container {
    position: absolute;
    z-index: 2;
}

.tile, .tile .tile-inner {
    width: 106.25px;
    height: 106.25px;
    line-height: 106.25px;
}

.tile {
    position: absolute;
    transition: 100ms ease-in-out;
    transition-property: transform;
}

.tile .tile-inner {
    border-radius: 3px;
    background: #eee4da;
    text-align: center;
    font-weight: bold;
    z-index: 10;
    font-size: 55px;
}

/* 新方块出现动画 */
.tile.tile-new .tile-inner {
    animation: appear 200ms ease;
    animation-fill-mode: backwards;
}

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

/* 合并动画 */
.tile.tile-merged .tile-inner {
    z-index: 20;
    animation: pop 200ms ease;
    animation-fill-mode: backwards;
}

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

/* 方块位置类 */
.tile-position-1-1 { transform: translate(0px, 0px); }
.tile-position-1-2 { transform: translate(0px, 121px); }
.tile-position-1-3 { transform: translate(0px, 242px); }
.tile-position-1-4 { transform: translate(0px, 363px); }
.tile-position-2-1 { transform: translate(121px, 0px); }
.tile-position-2-2 { transform: translate(121px, 121px); }
.tile-position-2-3 { transform: translate(121px, 242px); }
.tile-position-2-4 { transform: translate(121px, 363px); }
.tile-position-3-1 { transform: translate(242px, 0px); }
.tile-position-3-2 { transform: translate(242px, 121px); }
.tile-position-3-3 { transform: translate(242px, 242px); }
.tile-position-3-4 { transform: translate(242px, 363px); }
.tile-position-4-1 { transform: translate(363px, 0px); }
.tile-position-4-2 { transform: translate(363px, 121px); }
.tile-position-4-3 { transform: translate(363px, 242px); }
.tile-position-4-4 { transform: translate(363px, 363px); }

/* 方块颜色 */
.tile-2 .tile-inner {
    background: #eee4da;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0), inset 0 0 0 1px rgba(255, 255, 255, 0);
    color: #776e65;
}

.tile-4 .tile-inner {
    background: #ede0c8;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0), inset 0 0 0 1px rgba(255, 255, 255, 0);
    color: #776e65;
}

.tile-8 .tile-inner {
    color: #f9f6f2;
    background: #f2b179;
}

.tile-16 .tile-inner {
    color: #f9f6f2;
    background: #f59563;
}

.tile-32 .tile-inner {
    color: #f9f6f2;
    background: #f67c5f;
}

.tile-64 .tile-inner {
    color: #f9f6f2;
    background: #f65e3b;
}

.tile-128 .tile-inner {
    color: #f9f6f2;
    background: #edcf72;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.2381), inset 0 0 0 1px rgba(255, 255, 255, 0.14286);
    font-size: 45px;
}

.tile-256 .tile-inner {
    color: #f9f6f2;
    background: #edcc61;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.31746), inset 0 0 0 1px rgba(255, 255, 255, 0.19048);
    font-size: 45px;
}

.tile-512 .tile-inner {
    color: #f9f6f2;
    background: #edc850;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.39683), inset 0 0 0 1px rgba(255, 255, 255, 0.2381);
    font-size: 45px;
}

.tile-1024 .tile-inner {
    color: #f9f6f2;
    background: #edc53f;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.47619), inset 0 0 0 1px rgba(255, 255, 255, 0.28571);
    font-size: 35px;
}

.tile-2048 .tile-inner {
    color: #f9f6f2;
    background: #edc22e;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.55556), inset 0 0 0 1px rgba(255, 255, 255, 0.33333);
    font-size: 35px;
}

.tile-super .tile-inner {
    color: #f9f6f2;
    background: #3c3a32;
    font-size: 30px;
}

/* 游戏说明 */
.game-explanation, .game-instructions {
    margin-top: 20px;
    line-height: 1.65;
}

hr {
    border: none;
    border-bottom: 1px solid #d8d4d0;
    margin-top: 20px;
    margin-bottom: 20px;
}

.important {
    text-decoration: underline;
}

/* 响应式设计 - 移动端 */
@media screen and (max-width: 520px) {
    html, body {
        font-size: 15px;
    }

    body {
        margin: 20px 0;
        padding: 0 20px;
    }

    .container {
        width: 280px;
        margin: 0 auto;
    }

    .title {
        font-size: 50px;
        margin-top: 15px;
    }

    .scores-container {
        margin-top: 10px;
    }

    .score-container, .best-container {
        min-width: 40px;
        padding: 10px;
    }

    .score-label, .best-label {
        font-size: 10px;
    }

    .score, .best {
        font-size: 20px;
    }

    .above-game {
        flex-direction: column;
        align-items: flex-start;
    }

    .game-intro {
        font-size: 14px;
        margin-bottom: 10px;
    }

    .restart-button {
        padding: 8px 15px;
        font-size: 14px;
    }

    .game-container {
        margin-top: 20px;
        padding: 10px;
        width: 280px;
        height: 280px;
    }

    .game-message p {
        font-size: 30px;
        height: 30px;
        line-height: 30px;
        margin-top: 90px;
    }

    .game-message .lower {
        margin-top: 30px;
    }

    .retry-button, .keep-playing-button {
        padding: 8px 15px;
        font-size: 14px;
    }

    .grid-row {
        margin-bottom: 10px;
    }

    .grid-cell {
        width: 57.5px;
        height: 57.5px;
        margin-right: 10px;
    }

    .tile, .tile .tile-inner {
        width: 57.5px;
        height: 57.5px;
        line-height: 57.5px;
    }

    .tile .tile-inner {
        font-size: 30px;
    }

    .tile-128 .tile-inner,
    .tile-256 .tile-inner,
    .tile-512 .tile-inner {
        font-size: 25px;
    }

    .tile-1024 .tile-inner,
    .tile-2048 .tile-inner {
        font-size: 20px;
    }

    .tile-super .tile-inner {
        font-size: 18px;
    }

    /* 移动端方块位置 */
    .tile-position-1-1 { transform: translate(0px, 0px); }
    .tile-position-1-2 { transform: translate(0px, 67px); }
    .tile-position-1-3 { transform: translate(0px, 135px); }
    .tile-position-1-4 { transform: translate(0px, 202px); }
    .tile-position-2-1 { transform: translate(67px, 0px); }
    .tile-position-2-2 { transform: translate(67px, 67px); }
    .tile-position-2-3 { transform: translate(67px, 135px); }
    .tile-position-2-4 { transform: translate(67px, 202px); }
    .tile-position-3-1 { transform: translate(135px, 0px); }
    .tile-position-3-2 { transform: translate(135px, 67px); }
    .tile-position-3-3 { transform: translate(135px, 135px); }
    .tile-position-3-4 { transform: translate(135px, 202px); }
    .tile-position-4-1 { transform: translate(202px, 0px); }
    .tile-position-4-2 { transform: translate(202px, 67px); }
    .tile-position-4-3 { transform: translate(202px, 135px); }
    .tile-position-4-4 { transform: translate(202px, 202px); }
}