:root {
    --neutral-900: #0a0a0a;
    --neutral-800: #1f1f1f;
    --neutral-700: #3f3f3f;
    --neutral-500: #737373;
    --neutral-200: #e5e5e5;
    --neutral-100: #f5f5f5;
    --accent: #111111;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family:
        ui-sans-serif,
        system-ui,
        -apple-system,
        "Segoe UI",
        sans-serif;
    color: var(--neutral-900);
    background: #ffffff;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.reveal {
    animation: fadeUp 0.6s ease-out both;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--neutral-200);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 72rem;
    margin: 0 auto;
    padding: 0 1.5rem;
    height: 3.5rem;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.header-actions {
    display: flex;
    gap: 0.75rem;
    align-items: center;
}

.button-primary {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--accent);
    color: #ffffff;
    border: none;
    border-radius: 0.9rem;
    padding: 0.6rem 1.1rem;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s ease;
}

.button-primary:hover {
    background: #000000;
}

.button-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.button-secondary {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: transparent;
    color: var(--neutral-900);
    border: 1px solid var(--neutral-200);
    border-radius: 0.9rem;
    padding: 0.6rem 1.1rem;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.button-secondary:hover {
    border-color: var(--accent);
    background: var(--neutral-100);
}

.container {
    max-width: 72rem;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.main-content {
    padding: 2rem 0;
}

.upload-zone {
    border: 2px dashed var(--neutral-200);
    border-radius: 0;
    padding: 3rem 1.5rem;
    text-align: center;
    transition: all 0.2s ease;
    background: #fafafa;
    cursor: pointer;
    min-height: calc(100vh - 3.5rem);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.upload-zone:hover {
    border-color: var(--accent);
    background: var(--neutral-100);
}

.upload-zone.dragover {
    border-color: var(--accent);
    background: var(--neutral-100);
    transform: scale(1.01);
}

.upload-zone h3 {
    margin: 0 0 0.5rem;
    font-size: 1.1rem;
    color: var(--neutral-900);
}

.upload-zone p {
    margin: 0;
    color: var(--neutral-700);
    font-size: 0.9rem;
}

.upload-zone input[type="file"] {
    display: none;
}

.preview-container {
    margin-top: 2rem;
    display: none;
}

.preview-container.active {
    display: block;
    animation: fadeUp 0.6s ease-out;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--neutral-200);
}

.preview-header h2 {
    margin: 0;
    font-size: 1.5rem;
    color: var(--neutral-900);
}

.preview-header .file-info {
    font-size: 0.85rem;
    color: var(--neutral-500);
}

.preview-content {
    background: #ffffff;
    border: 1px solid var(--neutral-200);
    border-radius: 1.2rem;
    padding: 2rem;
    line-height: 1.8;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

/* Markdown styling */
.preview-content h1 {
    font-size: 2.2rem;
    margin: 2rem 0 1rem;
    padding-bottom: 0.3rem;
    border-bottom: 1px solid var(--neutral-200);
}

.preview-content h2 {
    font-size: 1.8rem;
    margin: 1.8rem 0 0.8rem;
    color: var(--neutral-900);
}

.preview-content h3 {
    font-size: 1.4rem;
    margin: 1.5rem 0 0.6rem;
    color: var(--neutral-800);
}

.preview-content h4,
.preview-content h5,
.preview-content h6 {
    margin: 1.2rem 0 0.5rem;
    color: var(--neutral-800);
}

.preview-content p {
    margin: 1rem 0;
    color: var(--neutral-900);
}

.preview-content ul,
.preview-content ol {
    margin: 1rem 0;
    padding-left: 2rem;
}

.preview-content li {
    margin: 0.5rem 0;
}

.preview-content blockquote {
    margin: 1.5rem 0;
    padding: 1rem;
    padding-left: 1.5rem;
    border-left: 4px solid var(--accent);
    background: var(--neutral-100);
    color: var(--neutral-800);
    font-style: italic;
}

.preview-content code {
    background: var(--neutral-100);
    color: var(--neutral-900);
    padding: 0.2rem 0.5rem;
    border-radius: 0.4rem;
    font-family: "Courier New", monospace;
    font-size: 0.9em;
}

.preview-content pre {
    background: var(--neutral-900);
    color: #e0e0e0;
    padding: 1.5rem;
    border-radius: 0.9rem;
    overflow-x: auto;
    margin: 1.5rem 0;
    font-family: "Courier New", monospace;
    font-size: 0.9rem;
    line-height: 1.5;
}

.preview-content pre code {
    background: none;
    color: inherit;
    padding: 0;
}

.preview-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
}

.preview-content th {
    background: var(--neutral-100);
    padding: 0.75rem;
    text-align: left;
    font-weight: 600;
    border: 1px solid var(--neutral-200);
}

.preview-content td {
    padding: 0.75rem;
    border: 1px solid var(--neutral-200);
}

.preview-content tr:nth-child(even) {
    background: #fafafa;
}

.preview-content hr {
    border: none;
    border-top: 2px solid var(--neutral-200);
    margin: 2rem 0;
}

.preview-content img {
    max-width: 100%;
    height: auto;
    border-radius: 0.9rem;
    margin: 1rem 0;
}

.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--neutral-500);
}

.empty-state p {
    margin: 0.5rem 0;
}

.stats {
    margin-top: 1.5rem;
    padding: 1rem;
    background: var(--neutral-100);
    border-radius: 0.9rem;
    display: flex;
    justify-content: space-around;
    font-size: 0.9rem;
    color: var(--neutral-700);
}

.stat-item {
    text-align: center;
}

.stat-value {
    font-weight: 600;
    color: var(--neutral-900);
    font-size: 1.2rem;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--neutral-500);
    margin-top: 0.25rem;
}

@media (max-width: 640px) {
    .header-inner {
        height: auto;
        padding: 0.75rem 1.5rem;
    }

    .upload-zone {
        padding: 2rem 1rem;
    }

    .preview-content {
        padding: 1.5rem;
    }

    .preview-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .header-actions {
        flex-wrap: wrap;
        width: 100%;
    }

    .button-primary,
    .button-secondary {
        flex: 1;
        min-width: 120px;
    }

    .stats {
        flex-direction: column;
        gap: 1rem;
    }
}