/* CSS Reset and Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    /* Color Palette - Neutral Tones */
    --color-warm-white: #fefcfb;
    --color-off-white: #f8f6f4;
    --color-light-gray: #e8e6e4;
    --color-medium-gray: #a8a6a4;
    --color-deep-charcoal: #2c2a29;
    --color-charcoal: #3d3b3a;
    --color-muted-accent: #8b7355;
    --color-muted-accent-light: #a08671;
    --color-success: #6b8e23;
    --color-warning: #cd853f;
    --color-error: #8b4513;
    
    /* Typography */
    --font-serif: 'Playfair Display', Georgia, serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(44, 42, 41, 0.05);
    --shadow-md: 0 4px 6px rgba(44, 42, 41, 0.07), 0 2px 4px rgba(44, 42, 41, 0.06);
    --shadow-lg: 0 10px 15px rgba(44, 42, 41, 0.1), 0 4px 6px rgba(44, 42, 41, 0.05);
    --shadow-xl: 0 20px 25px rgba(44, 42, 41, 0.1), 0 10px 10px rgba(44, 42, 41, 0.04);
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 200ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Performance Optimizations */
html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-deep-charcoal);
    background-color: var(--color-warm-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-md);
}

/* Header */
.header {
    background-color: var(--color-warm-white);
    border-bottom: 1px solid var(--color-light-gray);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--space-md);
    padding-bottom: var(--space-md);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    text-decoration: none;
    color: var(--color-deep-charcoal);
}

.logo-icon {
    font-size: 2rem;
    line-height: 1;
}

.logo-text {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.025em;
}

.nav {
    display: flex;
    gap: var(--space-lg);
}

.nav-link {
    font-weight: 500;
    color: var(--color-charcoal);
    text-decoration: none;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--color-muted-accent);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-muted-accent);
    transition: width var(--transition-fast);
}

.nav-link:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    padding: var(--space-3xl) 0;
    background: linear-gradient(135deg, var(--color-warm-white) 0%, var(--color-off-white) 100%);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.hero-title {
    font-family: var(--font-serif);
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.025em;
    margin-bottom: var(--space-md);
    color: var(--color-deep-charcoal);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-charcoal);
    margin-bottom: var(--space-2xl);
    line-height: 1.5;
    font-weight: 400;
}

/* Upload Area */
.upload-area {
    background-color: var(--color-warm-white);
    border: 2px dashed var(--color-light-gray);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
    margin-bottom: var(--space-xl);
    transition: all var(--transition-normal);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.upload-area:hover {
    border-color: var(--color-muted-accent);
    background-color: var(--color-off-white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.upload-area.drag-over {
    border-color: var(--color-muted-accent);
    background-color: var(--color-off-white);
    transform: scale(1.02);
}

.upload-content {
    pointer-events: none;
}

.upload-icon {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    color: var(--color-medium-gray);
}

.upload-title {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-deep-charcoal);
}

.upload-subtitle {
    color: var(--color-charcoal);
    font-size: 1rem;
}

.upload-link {
    color: var(--color-muted-accent);
    font-weight: 500;
    text-decoration: underline;
    cursor: pointer;
}

.file-input {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: pointer;
}

/* Supported Formats */
.supported-formats {
    text-align: center;
}

.formats-label {
    color: var(--color-charcoal);
    margin-bottom: var(--space-sm);
    font-weight: 500;
}

.format-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    justify-content: center;
}

.format-tag {
    background-color: var(--color-off-white);
    color: var(--color-charcoal);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    border: 1px solid var(--color-light-gray);
}

/* Progress Section */
.progress-section {
    padding: var(--space-xl) 0;
    background-color: var(--color-off-white);
}

.progress-card {
    background-color: var(--color-warm-white);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    box-shadow: var(--shadow-md);
    max-width: 500px;
    margin: 0 auto;
    text-align: center;
}

.progress-title {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--space-lg);
    color: var(--color-deep-charcoal);
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--color-light-gray);
    border-radius: var(--radius-sm);
    overflow: hidden;
    margin-bottom: var(--space-md);
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--color-muted-accent), var(--color-muted-accent-light));
    width: 0%;
    transition: width var(--transition-normal);
    border-radius: var(--radius-sm);
}

.progress-text {
    color: var(--color-charcoal);
    font-size: 0.875rem;
}

/* File Explorer */
.file-explorer {
    padding: var(--space-xl) 0;
}

.explorer-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-xl);
    flex-wrap: wrap;
    gap: var(--space-md);
}

.explorer-title {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 600;
    color: var(--color-deep-charcoal);
}

.explorer-actions {
    display: flex;
    gap: var(--space-sm);
}

/* Buttons */
.btn {
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-md);
    border: none;
    font-weight: 500;
    font-size: 0.875rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
}

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

.btn-primary:hover {
    background-color: var(--color-muted-accent-light);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: var(--color-off-white);
    color: var(--color-charcoal);
    border: 1px solid var(--color-light-gray);
}

.btn-secondary:hover {
    background-color: var(--color-light-gray);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

/* File Tree */
.file-tree {
    background-color: var(--color-warm-white);
    border: 1px solid var(--color-light-gray);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.file-item {
    display: flex;
    align-items: center;
    padding: var(--space-sm) var(--space-md);
    border-bottom: 1px solid var(--color-light-gray);
    transition: background-color var(--transition-fast);
    cursor: pointer;
}

.file-item:hover {
    background-color: var(--color-off-white);
}

.file-item:last-child {
    border-bottom: none;
}

.file-icon {
    margin-right: var(--space-sm);
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

.file-name {
    flex: 1;
    font-weight: 500;
    color: var(--color-deep-charcoal);
}

.file-size {
    color: var(--color-medium-gray);
    font-size: 0.875rem;
    margin-left: var(--space-md);
}

.file-actions {
    display: flex;
    gap: var(--space-xs);
    margin-left: var(--space-md);
}

.file-action {
    padding: var(--space-xs);
    background: none;
    border: none;
    color: var(--color-muted-accent);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
}

.file-action:hover {
    background-color: var(--color-light-gray);
    color: var(--color-deep-charcoal);
}

.file-action svg {
    flex-shrink: 0;
}

/* Features Section */
.features {
    padding: var(--space-3xl) 0;
    background-color: var(--color-off-white);
}

.section-title {
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: var(--space-2xl);
    color: var(--color-deep-charcoal);
    letter-spacing: -0.025em;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-xl);
}

.feature-card {
    background-color: var(--color-warm-white);
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--space-lg);
    display: block;
}

.feature-title {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-deep-charcoal);
}

.feature-description {
    color: var(--color-charcoal);
    line-height: 1.6;
}

/* Supported Formats Section */
.supported {
    padding: var(--space-3xl) 0;
}

.formats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-xl);
}

.format-group {
    background-color: var(--color-warm-white);
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-light-gray);
}

.format-group-title {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--space-lg);
    color: var(--color-deep-charcoal);
}

.format-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.format-item {
    background-color: var(--color-off-white);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-weight: 500;
    color: var(--color-charcoal);
    border: 1px solid var(--color-light-gray);
}

/* Footer */
.footer {
    background-color: var(--color-deep-charcoal);
    color: var(--color-off-white);
    padding: var(--space-2xl) 0 var(--space-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
}

.footer-brand .logo {
    margin-bottom: var(--space-md);
}

.footer-brand .logo-text {
    color: var(--color-off-white);
}

.footer-description {
    color: var(--color-medium-gray);
    line-height: 1.6;
}

.footer-info h4 {
    font-family: var(--font-serif);
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-off-white);
}

.footer-info p {
    color: var(--color-medium-gray);
    line-height: 1.6;
}

.footer-bottom {
    border-top: 1px solid var(--color-charcoal);
    padding-top: var(--space-lg);
    text-align: center;
    color: var(--color-medium-gray);
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .nav {
        gap: var(--space-md);
    }
    
    .nav-link {
        font-size: 0.875rem;
    }
    
    .upload-area {
        padding: var(--space-lg);
    }
    
    .explorer-header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .explorer-actions {
        justify-content: center;
    }
    
    .format-tags {
        justify-content: flex-start;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: var(--space-2xl) 0;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .container {
        padding: 0 var(--space-sm);
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .formats-grid {
        grid-template-columns: 1fr;
    }
    
    .review-card {
        width: 280px;
        min-height: 240px;
        padding: var(--space-lg);
    }
    
    .reviews-track {
        gap: var(--space-md);
    }
}

/* Loading States */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--color-light-gray);
    border-top: 2px solid var(--color-muted-accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Performance Optimizations */
.will-change-transform {
    will-change: transform;
}

.will-change-opacity {
    will-change: opacity;
}

/* Folder styles */
.folder-item {
    font-weight: 600;
}

.folder-item .file-icon {
    color: var(--color-muted-accent);
}

.file-tree .nested {
    padding-left: var(--space-lg);
    border-left: 2px solid var(--color-light-gray);
    margin-left: var(--space-md);
}

.file-tree .nested .file-item {
    padding-left: var(--space-sm);
}

/* FAQ Section */
.faq {
    padding: var(--space-3xl) 0;
    background-color: var(--color-warm-white);
}

.faq-grid {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border: 1px solid var(--color-light-gray);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-md);
    overflow: hidden;
    background-color: var(--color-warm-white);
    box-shadow: var(--shadow-sm);
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    padding: var(--space-lg);
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-deep-charcoal);
    transition: background-color var(--transition-fast);
}

.faq-question:hover {
    background-color: var(--color-off-white);
}

.faq-question[aria-expanded="true"] {
    background-color: var(--color-off-white);
}

.faq-icon {
    font-size: 1.5rem;
    font-weight: 300;
    color: var(--color-muted-accent);
    transition: transform var(--transition-fast);
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 var(--space-lg) var(--space-lg);
    display: none;
    color: var(--color-charcoal);
    line-height: 1.6;
}

.faq-question[aria-expanded="true"] + .faq-answer {
    display: block;
    animation: fadeIn var(--transition-normal) ease-in;
}

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

/* Reviews Section */
.reviews {
    padding: var(--space-3xl) 0;
    background-color: var(--color-off-white);
    overflow: hidden;
}

.reviews-carousel {
    overflow: hidden;
    margin-bottom: var(--space-2xl);
    width: 100%;
    position: relative;
}

.reviews-track {
    display: flex;
    gap: var(--space-xl);
    width: max-content;
    animation: scroll-reviews 60s linear infinite;
}

@keyframes scroll-reviews {
    0% {
        transform: translateX(0);
    }
    100% {
        transform: translateX(-50%);
    }
}

.review-card {
    background-color: var(--color-warm-white);
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-light-gray);
    transition: all var(--transition-normal);
    flex-shrink: 0;
    width: 350px;
    min-height: 280px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

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

/* Pause animation on hover */
.reviews-track:hover {
    animation-play-state: paused;
}

.review-rating {
    font-size: 1.25rem;
    color: #ffd700;
    margin-bottom: var(--space-md);
}

.review-text {
    color: var(--color-charcoal);
    line-height: 1.6;
    margin-bottom: var(--space-lg);
    font-style: italic;
}

.review-author strong {
    display: block;
    font-weight: 600;
    color: var(--color-deep-charcoal);
    margin-bottom: var(--space-xs);
}

.review-author span {
    color: var(--color-medium-gray);
    font-size: 0.875rem;
}

.review-summary {
    background-color: var(--color-warm-white);
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-light-gray);
}

.rating-overview {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: var(--space-xl);
    align-items: center;
}

.overall-rating {
    text-align: center;
}

.rating-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--color-deep-charcoal);
    display: block;
}

.rating-stars {
    font-size: 1.5rem;
    color: #ffd700;
    margin: var(--space-sm) 0;
}

.rating-text {
    color: var(--color-medium-gray);
    font-size: 0.875rem;
}

.rating-breakdown {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.rating-bar {
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: var(--space-sm);
    align-items: center;
}

.rating-bar .stars {
    font-size: 0.875rem;
    color: var(--color-medium-gray);
    width: 40px;
}

.bar {
    height: 8px;
    background-color: var(--color-light-gray);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.bar .fill {
    height: 100%;
    background-color: #ffd700;
    transition: width var(--transition-normal);
}

.rating-bar .count {
    font-size: 0.875rem;
    color: var(--color-medium-gray);
    width: 80px;
    text-align: right;
}

/* Error states */
.error-message {
    background-color: #fef2f2;
    border: 1px solid #fecaca;
    color: var(--color-error);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    margin: var(--space-md) 0;
    font-weight: 500;
}

.success-message {
    background-color: #f0f9ff;
    border: 1px solid #bae6fd;
    color: var(--color-success);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    margin: var(--space-md) 0;
    font-weight: 500;
}

/* Responsive adjustments for new sections */
@media (max-width: 768px) {
    .rating-overview {
        grid-template-columns: 1fr;
        gap: var(--space-lg);
        text-align: center;
    }
    
    .nav {
        flex-wrap: wrap;
        justify-content: center;
        gap: var(--space-sm);
    }
    
    .nav-link {
        font-size: 0.875rem;
    }
    
    .review-card {
        width: 300px;
        min-height: 260px;
    }
    
    .reviews-track {
        gap: var(--space-lg);
    }
}