*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-color: #f5f5f5;
    --text-color: #333;
    --panel-bg: #ffffff;
    --panel-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --border-color: #e0e0e0;
    --accent-color: #4CAF50;
    --key-bg: #e8e8e8;
    --key-text: #333;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #e0e0e0;
    --panel-bg: #2d2d2d;
    --panel-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    --border-color: #404040;
    --accent-color: #66BB6A;
    --key-bg: #404040;
    --key-text: #e0e0e0;
}

body{
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: 'Arial', sans-serif;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 40px;
    background-color: var(--panel-bg);
    box-shadow: var(--panel-shadow);
    border-bottom: 1px solid var(--border-color);
}

.header h1 {
    font-size: 28px;
    font-weight: bold;
}

.theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 45px;
    height: 45px;
    font-size: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

.main-container {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    gap: 40px;
    padding: 30px;
    min-height: calc(100vh - 100px);
    max-width: 1400px;
    margin: 0 auto;
}

.instructions-panel {
    background-color: var(--panel-bg);
    border-radius: 12px;
    padding: 25px;
    box-shadow: var(--panel-shadow);
    border: 1px solid var(--border-color);
    width: 280px;
    height: fit-content;
    flex-shrink: 0;
}

.instructions-panel h3 {
    margin-bottom: 20px;
    font-size: 20px;
    color: var(--accent-color);
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: 8px;
}

.instruction-item {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 12px;
}

.key {
    background-color: var(--key-bg);
    color: var(--key-text);
    padding: 8px 12px;
    border-radius: 6px;
    font-weight: bold;
    min-width: 35px;
    text-align: center;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.action {
    font-size: 14px;
}

.game-tips {
    margin-top: 25px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.game-tips h4 {
    margin-bottom: 12px;
    color: var(--accent-color);
}

.game-tips ul {
    list-style: none;
    padding-left: 0;
}

.game-tips li {
    margin-bottom: 8px;
    padding-left: 20px;
    position: relative;
    font-size: 13px;
    line-height: 1.4;
}

.game-tips li::before {
    content: "•";
    color: var(--accent-color);
    position: absolute;
    left: 0;
    font-weight: bold;
}

.game-container{
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    flex-shrink: 0;
}

.score-panel {
    background-color: var(--panel-bg);
    border-radius: 12px;
    padding: 25px;
    box-shadow: var(--panel-shadow);
    border: 1px solid var(--border-color);
    width: 280px;
    height: fit-content;
    flex-shrink: 0;
}

.score-display {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    margin-bottom: 25px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

.score-label {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-color);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.score-value {
    font-size: 36px;
    font-weight: bold;
    color: var(--accent-color);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.game-stats h4 {
    margin-bottom: 15px;
    color: var(--accent-color);
    font-size: 18px;
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: 5px;
}

.stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    padding: 8px 0;
}

.stat-label {
    font-size: 14px;
    color: var(--text-color);
}

.stat-value {
    font-size: 18px;
    font-weight: bold;
    color: var(--accent-color);
}

#tetris{
    background-color: var(--panel-bg);
    border-radius: 8px;
    box-shadow: var(--panel-shadow);
    border: 2px solid var(--border-color);
}

.game-over-screen{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: none;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
}

.game-over-content{
    text-align: center;
    color: white;
    background-color: var(--panel-bg);
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.game-over-content h3{
    font-size: 24px;
    margin-bottom: 20px;
    color: var(--text-color);
}

.play-again-btn{
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 16px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
}

.play-again-btn:hover{
    background-color: #45a049;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

@media (max-width: 1200px) {
    .main-container {
        flex-direction: column;
        align-items: center;
        gap: 20px;
        padding: 20px;
    }
    
    .instructions-panel, .score-panel {
        width: 100%;
        max-width: 400px;
    }
    
    .instructions-panel {
        order: 2;
    }
    
    .score-panel {
        order: 3;
    }
    
    #tetris {
        width: 350px;
        height: 700px;
    }
}

@media (max-width: 768px) {
    .instructions-panel, .score-panel {
        max-width: 300px;
    }
    
    .header {
        padding: 15px 20px;
    }
    
    .header h1 {
        font-size: 24px;
    }
    
    #tetris {
        width: 300px;
        height: 600px;
    }
}