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

:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #6b7280;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --bg-color: #f9fafb;
    --card-bg: #ffffff;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 20px;
    color: var(--text-primary);
}

#stage {
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    padding: 40px;
    max-width: 500px;
    width: 100%;
    min-height: 400px;
    position: relative;
}

.step {
    display: none;
    animation: fadeIn 0.3s ease-in;
}

.step.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

h1, h2 {
    color: var(--text-primary);
    margin-bottom: 16px;
    text-align: center;
}

h1 {
    font-size: 28px;
    font-weight: 700;
}

h2 {
    font-size: 24px;
    font-weight: 600;
}

.subtitle {
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: 32px;
    font-size: 14px;
    line-height: 1.5;
}

.button-group {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-top: 32px;
}

.btn {
    padding: 14px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    width: 100%;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

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

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

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

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

.btn-secondary:hover {
    background: #4b5563;
}

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

.btn-success:hover {
    background: #059669;
}

.icon {
    font-size: 20px;
}

.back {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    display: inline-block;
    margin-bottom: 20px;
    transition: color 0.2s;
}

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

.file-input-wrapper {
    margin: 32px 0;
    text-align: center;
}

.file-info {
    margin-top: 16px;
    padding: 12px;
    background: var(--bg-color);
    border-radius: 8px;
    font-size: 14px;
    color: var(--text-secondary);
    min-height: 20px;
}

.file-info.has-file {
    color: var(--text-primary);
    border: 2px solid var(--success-color);
}

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

.password-input {
    width: 100%;
    padding: 14px 50px 14px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.2s;
}

.password-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.toggle-password {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    font-size: 20px;
    opacity: 0.6;
    transition: opacity 0.2s;
}

.toggle-password:hover {
    opacity: 1;
}

.password-strength {
    margin-bottom: 20px;
    font-size: 14px;
    min-height: 24px;
}

.password-strength.weak {
    color: var(--danger-color);
}

.password-strength.medium {
    color: #f59e0b;
}

.password-strength.strong {
    color: var(--success-color);
}

.progress-container {
    margin: 32px 0;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--bg-color);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 12px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--success-color));
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    text-align: center;
    color: var(--text-secondary);
    font-size: 14px;
}

.success-icon {
    width: 80px;
    height: 80px;
    margin: 32px auto;
    background: var(--success-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
    color: white;
    animation: scaleIn 0.5s ease;
}

@keyframes scaleIn {
    from {
        transform: scale(0);
    }
    to {
        transform: scale(1);
    }
}

footer {
    margin-top: 24px;
    text-align: center;
    color: white;
    font-size: 14px;
    opacity: 0.9;
}

.encrypt-view,
.decrypt-view {
    display: none;
}

body.encrypt .encrypt-view {
    display: block;
}

body.decrypt .decrypt-view {
    display: block;
}

.error-message {
    background: #fee2e2;
    color: var(--danger-color);
    padding: 12px;
    border-radius: 8px;
    margin: 16px 0;
    font-size: 14px;
    text-align: center;
}

@media (max-width: 640px) {
    #stage {
        padding: 24px;
    }
    
    h1 {
        font-size: 24px;
    }
    
    h2 {
        font-size: 20px;
    }
}
/* Site Header */
.site-header {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    padding: 20px 0;
    margin-bottom: 30px;
    border-radius: 16px;
    max-width: 1200px;
    width: 100%;
    margin-left: auto;
    margin-right: auto;
}

.site-header .container {
    text-align: center;
}

.logo {
    font-size: 32px;
    font-weight: 700;
    color: white;
    margin: 0;
}

.tagline {
    color: rgba(255, 255, 255, 0.9);
    margin: 8px 0 0 0;
    font-size: 16px;
}

/* Information Sections */
.info-section {
    background: white;
    width: 100%;
    padding: 60px 20px;
    margin-top: 40px;
}

.info-section.alt-bg {
    background: var(--bg-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 40px;
    color: var(--text-primary);
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
    margin-top: 40px;
}

.feature-card {
    background: white;
    padding: 32px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-align: center;
    transition: transform 0.2s;
}

.info-section.alt-bg .feature-card {
    background: white;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 14px;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* Steps List */
.steps-list {
    max-width: 800px;
    margin: 0 auto;
}

.step-item {
    display: flex;
    gap: 24px;
    margin-bottom: 32px;
    align-items: flex-start;
}

.step-number {
    width: 48px;
    height: 48px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 700;
    flex-shrink: 0;
}

.step-content h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.step-content p {
    font-size: 15px;
    line-height: 1.6;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.step-content strong {
    color: var(--danger-color);
}

/* Use Cases */
.use-cases {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.use-case {
    background: white;
    padding: 24px;
    border-radius: 12px;
    border-left: 4px solid var(--primary-color);
}

.info-section.alt-bg .use-case {
    background: white;
}

.use-case h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.use-case p {
    font-size: 14px;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* Technical Details */
.tech-details {
    display: grid;
    gap: 32px;
    max-width: 900px;
    margin: 0 auto;
}

.tech-item {
    background: white;
    padding: 24px;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.tech-item h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.tech-item p {
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.tech-item ul {
    list-style: none;
    padding: 0;
}

.tech-item li {
    font-size: 14px;
    line-height: 1.8;
    color: var(--text-secondary);
    padding-left: 24px;
    position: relative;
    margin-bottom: 8px;
}

.tech-item li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: 700;
}

/* Best Practices */
.best-practices {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.practice-card {
    background: white;
    padding: 24px;
    border-radius: 12px;
    border-top: 4px solid var(--primary-color);
}

.practice-card.important {
    border-top-color: var(--danger-color);
    background: #fef2f2;
}

.practice-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.practice-card ul {
    list-style: none;
    padding: 0;
}

.practice-card li {
    font-size: 14px;
    line-height: 1.7;
    color: var(--text-secondary);
    padding-left: 20px;
    position: relative;
    margin-bottom: 12px;
}

.practice-card li:before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 700;
    font-size: 20px;
}

.practice-card.important li:before {
    color: var(--danger-color);
}

/* FAQ */
.faq-list {
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background: white;
    padding: 24px;
    border-radius: 12px;
    margin-bottom: 16px;
    box-shadow: var(--shadow);
}

.faq-item h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.faq-item p {
    font-size: 14px;
    line-height: 1.7;
    color: var(--text-secondary);
    margin: 0;
}

.faq-item strong {
    color: var(--text-primary);
}

/* Site Footer */
.site-footer {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    padding: 30px 20px;
    margin-top: 40px;
    border-radius: 16px;
    max-width: 1200px;
    width: 100%;
    margin-left: auto;
    margin-right: auto;
    text-align: center;
}

.privacy-notice {
    font-size: 16px;
    color: white;
    margin-bottom: 12px;
    font-weight: 500;
}

.copyright {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.8);
    margin: 0;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .features-grid,
    .use-cases,
    .best-practices {
        grid-template-columns: 1fr;
    }
    
    .section-title {
        font-size: 24px;
    }
    
    .step-item {
        flex-direction: column;
    }
    
    .info-section {
        padding: 40px 20px;
    }
}
.breadcrumb {
    list-style: none;
    display: flex;
    gap: 8px;
    padding: 12px 20px;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 8px;
    margin: 0 auto 20px;
    max-width: 1200px;
    font-size: 14px;
}

.breadcrumb li {
    color: rgba(255, 255, 255, 0.8);
}

.breadcrumb a {
    color: white;
    text-decoration: none;
}

.breadcrumb a:hover {
    text-decoration: underline;
}