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

:root {
    --primary-color: #000000;
    --primary-hover: #333333;
    --secondary-color: #ffffff;
    --background: #0a0a0a;
    --card-background: #1a1a1a;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --border-color: #333333;
    --success-color: #ffffff;
    --error-color: #ffffff;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.7);
    --accent-gray: #2a2a2a;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    background-image: 
        radial-gradient(circle at 20% 50%, rgba(255, 255, 255, 0.02) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(255, 255, 255, 0.02) 0%, transparent 50%);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

header {
    text-align: left;
    margin-bottom: 4rem;
    padding: 2rem 0;
    border-bottom: 2px solid var(--border-color);
}

header h1 {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 0.75rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

header p {
    color: var(--text-secondary);
    font-size: 1.15rem;
    font-weight: 300;
}

section {
    background: var(--card-background);
    border-radius: 0;
    padding: 2.5rem;
    margin-bottom: 3rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--secondary-color);
}

h2 {
    color: var(--secondary-color);
    margin-bottom: 2rem;
    font-size: 1.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

/* Upload Section */
.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 0;
    padding: 4rem 3rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--background);
    border-color: var(--border-color);
}

.upload-area:hover {
    border-color: var(--secondary-color);
    background: var(--accent-gray);
}

.upload-area.dragover {
    border-color: var(--secondary-color);
    background: var(--accent-gray);
    border-style: solid;
}

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

.upload-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 1rem;
    color: var(--text-secondary);
    stroke-width: 2;
}

.upload-area:hover .upload-icon {
    color: var(--secondary-color);
}

.upload-content p {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.file-info {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.upload-progress {
    margin-top: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.progress-bar {
    flex: 1;
    height: 10px;
    background: var(--border-color);
    border-radius: 0;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--secondary-color);
    width: 0%;
    transition: width 0.3s ease;
}

.progress-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
    min-width: 40px;
}

.message {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 8px;
    display: none;
}

.message.success {
    display: block;
    background: var(--accent-gray);
    color: var(--secondary-color);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--secondary-color);
}

.message.error {
    display: block;
    background: var(--accent-gray);
    color: var(--secondary-color);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--text-secondary);
}

/* PDF List */
.pdf-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
}

.pdf-item {
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: 0;
    padding: 2rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    border-left: 3px solid var(--border-color);
}

.pdf-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    border-color: var(--secondary-color);
    border-left-color: var(--secondary-color);
    background: var(--accent-gray);
}

.pdf-icon {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
    letter-spacing: 0.2em;
    color: var(--text-secondary);
    text-transform: uppercase;
    border: 2px solid var(--border-color);
    padding: 0.75rem 1.5rem;
    width: fit-content;
    transition: all 0.3s ease;
}

.pdf-item:hover .pdf-icon {
    border-color: var(--secondary-color);
    color: var(--secondary-color);
}

.pdf-name {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    word-break: break-word;
    width: 100%;
}

.pdf-size {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
    font-style: italic;
}

.loading {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-size: 0.9rem;
}

.refresh-btn {
    background: var(--secondary-color);
    color: var(--primary-color);
    border: 2px solid var(--secondary-color);
    padding: 0.75rem 1.5rem;
    border-radius: 0;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.refresh-btn:hover {
    background: transparent;
    color: var(--secondary-color);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.95);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 2rem;
}

.modal-content {
    background: var(--card-background);
    border-radius: 0;
    width: 100%;
    max-width: 1200px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
}

.modal-header {
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    color: var(--text-primary);
    font-size: 1.5rem;
}

.close-btn {
    background: none;
    border: 2px solid var(--border-color);
    font-size: 2rem;
    color: var(--text-secondary);
    cursor: pointer;
    line-height: 1;
    padding: 0;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 0;
    transition: all 0.3s ease;
}

.close-btn:hover {
    background: var(--secondary-color);
    color: var(--primary-color);
    border-color: var(--secondary-color);
}

.modal-body {
    flex: 1;
    padding: 2rem;
    overflow: hidden;
    display: flex;
}

.modal-body iframe {
    width: 100%;
    height: 70vh;
    border: 1px solid var(--border-color);
    border-radius: 0;
    background: var(--background);
}

/* Reviews and Activity Container */
.reviews-activity-container {
    display: grid;
    grid-template-columns: 1fr;
    gap: 3rem;
    margin-bottom: 0;
}

@media (min-width: 1024px) {
    .reviews-activity-container {
        grid-template-columns: 1.5fr 1fr;
    }
}

/* Reviews section */
.reviews-section {
    margin-bottom: 0;
}

.review-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.form-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 1rem;
}

.review-form input[type="text"] {
    flex: 1;
    min-width: 160px;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0;
    font-size: 1rem;
    background: var(--background);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.review-form input[type="text"]::placeholder {
    color: var(--text-secondary);
    opacity: 0.6;
}

.review-form input[type="text"]:focus {
    outline: none;
    border-color: var(--secondary-color);
    border-left: 3px solid var(--secondary-color);
}

.review-form textarea {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0;
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    background: var(--background);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.review-form textarea::placeholder {
    color: var(--text-secondary);
    opacity: 0.6;
}

.review-form textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
    border-left: 3px solid var(--secondary-color);
}

.rating-input {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.rating-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-right: 0.25rem;
}

.rating-input .star {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--border-color);
    cursor: pointer;
    padding: 0;
    transition: color 0.2s;
}

.rating-input .star:hover,
.rating-input .star.active {
    color: var(--secondary-color);
}

.submit-review-btn {
    align-self: flex-start;
    background: var(--secondary-color);
    color: var(--primary-color);
    border: 2px solid var(--secondary-color);
    padding: 0.75rem 1.5rem;
    border-radius: 0;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.submit-review-btn:hover {
    background: transparent;
    color: var(--secondary-color);
}

.review-message {
    margin-bottom: 1rem;
    padding: 0.75rem;
    border-radius: 8px;
    display: none;
}

.review-message.success {
    display: block;
    background: var(--accent-gray);
    color: var(--secondary-color);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--secondary-color);
}

.review-message.error {
    display: block;
    background: var(--accent-gray);
    color: var(--secondary-color);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--text-secondary);
}

.reviews-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.review-card {
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: 0;
    padding: 1.5rem;
    border-left: 3px solid var(--border-color);
    transition: all 0.3s ease;
}

.review-card:hover {
    border-left-color: var(--secondary-color);
    background: var(--accent-gray);
}

.review-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.review-author {
    font-weight: 600;
    color: var(--text-primary);
}

.review-date {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.review-stars {
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
}

.review-stars .star-dim {
    color: var(--border-color);
    opacity: 0.3;
}

.review-text {
    color: var(--text-primary);
    margin: 0;
    white-space: pre-wrap;
    word-break: break-word;
}

/* Activity section */
.activity-section {
    margin-bottom: 0;
}

.activity-section .section-header {
    margin-bottom: 1rem;
}

.refresh-btn.secondary {
    background: transparent;
    color: var(--secondary-color);
    border-color: var(--border-color);
}

.refresh-btn.secondary:hover {
    background: var(--secondary-color);
    color: var(--primary-color);
    border-color: var(--secondary-color);
}

.activity-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.activity-item {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem 1rem;
    padding: 1rem 1.25rem;
    background: var(--background);
    border-radius: 0;
    border: 1px solid var(--border-color);
    border-left: 3px solid var(--border-color);
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.activity-item:hover {
    border-left-color: var(--secondary-color);
    background: var(--accent-gray);
}

.activity-action {
    font-weight: 600;
    color: var(--secondary-color);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 0.85rem;
}

.activity-details {
    color: var(--text-secondary);
    max-width: 100%;
    overflow: hidden;
    text-overflow: ellipsis;
}

.activity-time {
    margin-left: auto;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1.5rem 1rem;
    }

    header {
        text-align: center;
        padding: 1.5rem 0;
    }

    header h1 {
        font-size: 2rem;
    }

    section {
        padding: 1.5rem;
    }

    .upload-area {
        padding: 2.5rem 1rem;
    }

    .pdf-list {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .modal-body {
        padding: 1rem;
    }

    .modal-body iframe {
        height: 60vh;
    }

    .form-row {
        flex-direction: column;
        align-items: stretch;
    }

    .rating-input {
        justify-content: flex-start;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .reviews-activity-container {
        grid-template-columns: 1fr;
    }
}