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

:root {
    --primary-color: #0d6efd;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --dark-color: #212529;
    --light-color: #f8f9fa;
    --gray-color: #6c757d;
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: #f5f7fa;
    color: var(--dark-color);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 40px;
    position: relative;
}

h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--dark-color);
    margin-bottom: 10px;
}

.language-selector {
    position: absolute;
    top: 0;
    right: 0;
}

.language-selector select {
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    background-color: white;
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
}

.language-selector select:hover {
    border-color: var(--primary-color);
}

main {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 30px;
}

section {
    margin-bottom: 40px;
}

section:last-child {
    margin-bottom: 0;
}

h2 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--dark-color);
}

h3 {
    font-size: 1.1rem;
    margin-bottom: 15px;
    color: var(--gray-color);
}

.input-group {
    position: relative;
    margin-bottom: 20px;
}

input[type="password"],
input[type="text"] {
    width: 100%;
    padding: 12px 45px 12px 15px;
    font-size: 16px;
    border: 2px solid #e0e0e0;
    border-radius: var(--border-radius);
    transition: var(--transition);
}

input[type="password"]:focus,
input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.toggle-btn {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
    color: var(--gray-color);
    transition: var(--transition);
}

.toggle-btn:hover {
    color: var(--primary-color);
}

.eye-icon {
    width: 20px;
    height: 20px;
}

.toggle-btn.show .eye-icon {
    stroke: var(--primary-color);
}

.strength-meter {
    margin-bottom: 20px;
}

.strength-bar {
    width: 100%;
    height: 8px;
    background-color: #e0e0e0;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 10px;
}

.strength-fill {
    height: 100%;
    width: 0;
    transition: width 0.3s ease, background-color 0.3s ease;
}

.strength-text {
    font-weight: 600;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.criteria ul {
    list-style: none;
}

.criteria li {
    padding: 8px 0;
    display: flex;
    align-items: center;
    color: var(--gray-color);
    transition: var(--transition);
}

.criteria li.met {
    color: var(--success-color);
}

.criteria .icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    margin-right: 10px;
    font-weight: bold;
}

.generator-options {
    margin-bottom: 20px;
}

.option {
    margin-bottom: 20px;
}

.option label {
    display: inline-block;
    margin-bottom: 5px;
    font-weight: 500;
}

input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: #e0e0e0;
    outline: none;
    -webkit-appearance: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
}

#lengthValue {
    display: inline-block;
    margin-left: 10px;
    font-weight: 600;
    color: var(--primary-color);
    min-width: 30px;
}

.checkbox-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.checkbox-group label {
    display: flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.checkbox-group input[type="checkbox"] {
    margin-right: 8px;
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.generated-password {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

#generatedPassword {
    flex: 1;
    padding: 12px 15px;
    font-family: 'Courier New', monospace;
    font-size: 16px;
    letter-spacing: 1px;
}

.copy-btn,
.generate-btn {
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.copy-btn {
    background-color: var(--gray-color);
    color: white;
}

.copy-btn:hover {
    background-color: #5a6268;
}

.generate-btn {
    background-color: var(--primary-color);
    color: white;
    width: 100%;
}

.generate-btn:hover {
    background-color: #0b5ed7;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(13, 110, 253, 0.3);
}

.tips-section {
    background-color: #f8f9fa;
    padding: 20px;
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
}

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

.tips-section li {
    padding: 8px 0;
    padding-left: 25px;
    position: relative;
}

.tips-section li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
    font-size: 20px;
}

footer {
    text-align: center;
    margin-top: 40px;
    padding: 20px;
    color: var(--gray-color);
    font-size: 14px;
}

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    main {
        padding: 20px;
    }
    
    h1 {
        font-size: 1.5rem;
    }
    
    h2 {
        font-size: 1.25rem;
    }
    
    .language-selector {
        position: static;
        margin-top: 15px;
    }
    
    .checkbox-group {
        grid-template-columns: 1fr;
    }
    
    .generated-password {
        flex-direction: column;
    }
    
    .copy-btn {
        width: 100%;
    }
}