body {
    background: #faf8ef;
    transition: 0.3s;
}

body.dark {
    background: #121212;
    color: white;
}

body.gradient {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
}

.settings-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    font-size: 24px;
    background: none;
    border: none;
    cursor: pointer;
}

.timer {
    font-size: 28px;
    font-weight: bold;
    margin-bottom: 10px;
    background: rgba(0,0,0,0.1);
    display: inline-block;
    padding: 5px 15px;
    border-radius: 10px;
}

.grid {
    display: grid;
    grid-template-columns: repeat(4, 80px);
    gap: 10px;
    justify-content: center;
    margin-top: 20px;
    background: rgba(0,0,0,0.2);
    padding: 10px;
    border-radius: 10px;
}

.cell {
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    font-weight: bold;
    border-radius: 5px;
    background: #fff;
}

.cell[data-value="2"] { background: #eee4da; }
.cell[data-value="4"] { background: #ede0c8; }
.cell[data-value="8"] { background: #f2b179; }
.cell[data-value="16"] { background: #f59563; }
.cell[data-value="32"] { background: #f67c5f; }
.cell[data-value="64"] { background: #f65e3b; }
.cell[data-value="128"] { background: #edcf72; }
.cell[data-value="256"] { background: #edcc61; }
.cell[data-value="512"] { background: #edc850; }
.cell[data-value="1024"] { background: #edc53f; }
.cell[data-value="2048"] { background: #edc22e; }
.cell[data-value="4096"] { background: #3c3a32; color: white; }
.cell[data-value="8192"] { background: #1a1a1a; color: white; }