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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.game-container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

.header {
    background: linear-gradient(135deg, #ff6b6b, #ee5a24);
    color: white;
    padding: 30px 20px;
    text-align: center;
}

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.header p {
    font-size: 1.1em;
    opacity: 0.9;
}

.game-board {
    padding: 30px;
}

.equations-container {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 25px;
    margin-bottom: 25px;
    border: 2px solid #e9ecef;
}

.equation {
    font-size: 2em;
    text-align: center;
    margin: 15px 0;
    padding: 15px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.emoji-values {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    margin-bottom: 25px;
}

.emoji-input {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
    border: 2px solid #dee2e6;
}

.emoji-display {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.emoji-input input {
    width: 100px;
    padding: 10px;
    border: 2px solid #ced4da;
    border-radius: 5px;
    font-size: 1.1em;
    text-align: center;
    transition: border-color 0.3s;
}

.emoji-input input:focus {
    outline: none;
    border-color: #667eea;
}

.controls {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 25px;
    flex-wrap: wrap;
}

button {
    padding: 12px 25px;
    border: none;
    border-radius: 8px;
    font-size: 1.1em;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 600;
}

#checkButton {
    background: #51cf66;
    color: white;
}

#checkButton:hover {
    background: #40c057;
    transform: translateY(-2px);
}

#hintButton {
    background: #ffd43b;
    color: white;
}

#hintButton:hover {
    background: #fcc419;
    transform: translateY(-2px);
}

#newGameButton {
    background: #748ffc;
    color: white;
}

#newGameButton:hover {
    background: #5c7cfa;
    transform: translateY(-2px);
}

.feedback {
    text-align: center;
    padding: 20px;
    border-radius: 10px;
    background: #e7f5ff;
    border: 2px solid #a5d8ff;
}

#message {
    font-size: 1.2em;
    margin-bottom: 15px;
    color: #1864ab;
}

.hint-container {
    background: #fff3bf;
    border: 2px solid #ffd43b;
    border-radius: 8px;
    padding: 15px;
    margin-top: 15px;
}

#hintText {
    color: #e67700;
    font-style: italic;
}

.correct {
    border-color: #51cf66 !important;
    background: #d3f9d8 !important;
}

.incorrect {
    border-color: #ff6b6b !important;
    background: #ffe3e3 !important;
}

/* Responsive design */
@media (max-width: 600px) {
    .game-container {
        margin: 10px;
    }
    
    .header h1 {
        font-size: 2em;
    }
    
    .equation {
        font-size: 1.5em;
    }
    
    .controls {
        flex-direction: column;
        align-items: center;
    }
    
    button {
        width: 100%;
        max-width: 250px;
    }
}