* {
    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;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: #333;
    padding: 20px;
}

.container {
    background: white;
    padding: 40px 30px;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    text-align: center;
    max-width: 400px;
    width: 100%;
}

h1 {
    color: #4a90e2;
    margin-bottom: 20px;
    font-size: 2em;
}

#userInput {
    width: 120px;
    padding: 15px;
    font-size: 1.5em;
    border: 3px solid #ddd;
    border-radius: 10px;
    text-align: center;
    margin-right: 10px;
    transition: border-color 0.3s;
}

#userInput:focus {
    outline: none;
    border-color: #4a90e2;
}

#guessButton {
    padding: 15px 30px;
    font-size: 1.2em;
    background: #50c878;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: background 0.3s, transform 0.1s;
}

#guessButton:hover {
    background: #45b26f;
}

#guessButton:active {
    transform: scale(0.98);
}

#feedback {
    margin-top: 20px;
    font-size: 1.3em;
    min-height: 40px;
    font-weight: bold;
}

.success { color: #50c878; }
.error { color: #e74c3c; }

@media (max-width: 480px) {
    .container { padding: 30px 20px; }
    h1 { font-size: 1.5em; }
}