:root {
    --primary: #667eea;
    --primary-dark: #5a67d8;
    --white: #ffffff;
    --gray-100: #f3f4f6;
    --gray-300: #d1d5db;
    --gray-800: #1f2937;
    --danger: #f56565;
    --success: #48bb78;
}

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

body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 500px;
    margin: 0 auto;
    background: white;
    border-radius: 15px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    overflow: hidden;
}

.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 30px 20px;
}

.title {
    font-size: 2rem;
    font-weight: bold;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.main-content {
    padding: 30px;
}

.password-display {
    margin-bottom: 30px;
}

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

.password-field {
    flex: 1;
    padding: 15px;
    border: 2px solid var(--gray-300);
    border-radius: 8px;
    font-family: monospace;
    font-size: 16px;
    background: var(--gray-100);
}

.copy-btn {
    padding: 15px 20px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
}

.copy-btn:hover {
    background: var(--primary-dark);
}

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

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: bold;
}

.slider {
    width: 100%;
    height: 8px;
    background: var(--gray-300);
    border-radius: 5px;
    outline: none;
}

.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
}

.checkbox-label input {
    width: 18px;
    height: 18px;
}

.generate-btn {
    width: 100%;
    padding: 15px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 18px;
    font-weight: bold;
    cursor: pointer;
    text-transform: uppercase;
}

.generate-btn:hover {
    background: var(--primary-dark);
}

.error-message {
    color: var(--danger);
    margin-top: 15px;
    padding: 10px;
    background: #fee;
    border-radius: 5px;
    display: none;
}

.error-message.show {
    display: block;
}

.copied {
    background: var(--success) !important;
}

@media (max-width: 600px) {
    .password-output {
        flex-direction: column;
    }
}