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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    max-width: 500px;
    width: 100%;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 28px;
}

.controls {
    margin-bottom: 30px;
}

.control-group {
    margin-bottom: 25px;
}

.control-group label {
    display: block;
    margin-bottom: 10px;
    color: #555;
    font-weight: 500;
}

.length-control {
    display: flex;
    align-items: center;
    gap: 15px;
}

#length {
    flex: 1;
    height: 6px;
    border-radius: 3px;
    background: #e0e0e0;
    outline: none;
    -webkit-appearance: none;
}

#length::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #667eea;
    cursor: pointer;
}

#length::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #667eea;
    cursor: pointer;
    border: none;
}

#length-value {
    font-weight: 600;
    color: #667eea;
    min-width: 30px;
    text-align: right;
}

.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    cursor: pointer;
    padding: 8px;
    border-radius: 6px;
    transition: background-color 0.2s;
}

.checkbox-label:hover {
    background-color: #f5f5f5;
}

.checkbox-label input[type="checkbox"] {
    margin-right: 10px;
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.generate-btn {
    width: 100%;
    padding: 14px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    margin-top: 10px;
}

.generate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.generate-btn:active {
    transform: translateY(0);
}

.result {
    margin-top: 30px;
}

.password-display {
    display: flex;
    gap: 10px;
    margin-bottom: 10px;
}

@media (max-width: 480px) {
    .password-display {
        flex-direction: column;
    }
    
    .copy-btn {
        width: 100%;
    }
}

#password {
    flex: 1;
    padding: 14px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 16px;
    font-family: 'Courier New', monospace;
    background-color: #f9f9f9;
    color: #333;
    text-align: center;
}

#password:focus {
    outline: none;
    border-color: #667eea;
}

.copy-btn {
    padding: 14px 24px;
    background: #4caf50;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
}

.copy-btn:hover {
    background: #45a049;
}

.copy-btn:active {
    background: #3d8b40;
}

.message {
    text-align: center;
    color: #4caf50;
    font-size: 14px;
    min-height: 20px;
    margin-top: 5px;
}

.message.show {
    animation: fadeIn 0.3s;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}