:root {
    --true-black: #1a1a1a;
    --near-black: #2a2a2a;
    --caption-gray: #5a5a6a;
    --paper-white: #ffffff;
    --abstract-blue: #3a7ca5;
    --table-stripe: #f7f7f9;
    --chart-gold: #d4a843;
    --rule-gray: #d0d0d0;
    --teal-accent: #2a9d8f;
}

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

body {
    font-family: 'Lora', serif;
    background: var(--paper-white);
    color: var(--near-black);
    line-height: 1.82;
    counter-reset: section figure table;
}

/* Running Header */
.running-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 2rem;
    background: var(--paper-white);
    border-bottom: 1px solid var(--rule-gray);
    z-index: 100;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.05em;
    color: var(--caption-gray);
}

.header-domain {
    font-weight: 500;
    color: var(--true-black);
}

/* Paper Layout */
.paper {
    max-width: 680px;
    margin: 0 auto;
    padding: 5rem 2rem 4rem;
}

/* Title Block */
.title-block {
    padding-bottom: 2rem;
    border-bottom: 2px solid var(--true-black);
    margin-bottom: 2rem;
}

.paper-title {
    font-family: 'Lora', serif;
    font-size: clamp(1.6rem, 3.5vw, 2.4rem);
    font-weight: 700;
    color: var(--true-black);
    line-height: 1.3;
    margin-bottom: 1rem;
}

.author-line {
    margin-bottom: 0.5rem;
}

.author {
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--near-black);
}

.meta-line {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    color: var(--caption-gray);
    letter-spacing: 0.03em;
    margin-bottom: 1.5rem;
}

.meta-sep {
    margin: 0 0.5rem;
    color: var(--rule-gray);
}

/* Abstract */
.abstract-block {
    border-left: 3px solid var(--abstract-blue);
    padding-left: 1.5rem;
    margin-top: 1.5rem;
}

.abstract-heading {
    font-family: 'Lora', serif;
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--abstract-blue);
    margin-bottom: 0.5rem;
}

.abstract-text {
    font-family: 'Lora', serif;
    font-size: 0.9rem;
    font-weight: 400;
    color: var(--near-black);
    line-height: 1.75;
    margin-bottom: 0.75rem;
}

.keywords {
    font-family: 'Inter', sans-serif;
    font-size: 0.75rem;
    color: var(--caption-gray);
}

.keyword-label {
    font-weight: 500;
    color: var(--near-black);
}

.keyword {
    font-style: italic;
}

/* Paper Sections */
.paper-section {
    margin-bottom: 2.5rem;
    counter-increment: section;
}

.section-heading {
    font-family: 'Lora', serif;
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--true-black);
    margin-bottom: 1rem;
    padding-top: 0.5rem;
}

.section-heading::before {
    content: counter(section) ". ";
    font-family: 'JetBrains Mono', monospace;
    font-size: 1rem;
    font-weight: 400;
    color: var(--caption-gray);
}

.body-text {
    font-family: 'Lora', serif;
    font-size: clamp(0.95rem, 1.3vw, 1.08rem);
    font-weight: 400;
    color: var(--near-black);
    line-height: 1.82;
    margin-bottom: 1rem;
    text-align: justify;
    hyphens: auto;
}

/* Footnotes */
.footnote {
    font-family: 'Inter', sans-serif;
    font-size: 0.75rem;
    color: var(--caption-gray);
    border-top: 1px solid var(--rule-gray);
    padding-top: 0.5rem;
    margin-top: 1rem;
    line-height: 1.5;
}

.fn-number {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    vertical-align: super;
    color: var(--abstract-blue);
    margin-right: 0.3rem;
}

.fn-text {
    color: var(--caption-gray);
}

/* Figures */
.figure {
    margin: 2rem 0;
    padding: 1.5rem;
    border: 1px solid var(--rule-gray);
    background: var(--table-stripe);
}

.figure-content {
    margin-bottom: 1rem;
    overflow-x: auto;
}

.dag-diagram {
    width: 100%;
    height: auto;
    max-height: 280px;
}

.node-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    fill: var(--near-black);
}

.node-label-sm {
    font-family: 'JetBrains Mono', monospace;
    font-size: 9px;
    fill: var(--caption-gray);
}

.figure-caption {
    font-family: 'Inter', sans-serif;
    font-size: 0.78rem;
    color: var(--caption-gray);
    line-height: 1.5;
}

.fig-label {
    font-weight: 600;
    color: var(--near-black);
}

/* Tables */
.data-table {
    width: 100%;
    border-collapse: collapse;
    font-family: 'Inter', sans-serif;
    font-size: 0.82rem;
}

.data-table thead {
    border-bottom: 2px solid var(--true-black);
}

.data-table th {
    font-weight: 600;
    color: var(--true-black);
    padding: 0.6rem 0.8rem;
    text-align: left;
    font-size: 0.75rem;
    letter-spacing: 0.03em;
}

.data-table td {
    padding: 0.5rem 0.8rem;
    border-bottom: 1px solid var(--rule-gray);
    color: var(--near-black);
}

.data-table tbody tr:nth-child(even) {
    background: var(--table-stripe);
}

.data-table tbody tr:hover {
    background: rgba(58, 124, 165, 0.05);
}

.hardness-cell {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
}

.hardness-bar {
    display: inline-block;
    height: 4px;
    background: linear-gradient(90deg, var(--teal-accent), var(--chart-gold));
    border-radius: 2px;
    max-width: 80px;
}

.table-figure {
    padding: 1rem;
}

/* References */
.references-section .section-heading::before {
    content: "";
}

.reference-list {
    padding-left: 1.5rem;
}

.reference-item {
    font-family: 'Inter', sans-serif;
    font-size: 0.8rem;
    color: var(--caption-gray);
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.reference-item em {
    color: var(--near-black);
}

/* Footer */
.paper-footer {
    max-width: 680px;
    margin: 0 auto;
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--rule-gray);
    display: flex;
    justify-content: space-between;
    align-items: baseline;
}

.footer-domain {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--true-black);
    letter-spacing: 0.05em;
}

.footer-note {
    font-family: 'Inter', sans-serif;
    font-size: 0.7rem;
    color: var(--caption-gray);
}

/* Scroll Reveal */
.paper-section,
.title-block {
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.paper-section.visible,
.title-block.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 768px) {
    .paper {
        padding: 4rem 1.2rem 3rem;
    }

    .running-header {
        padding: 0.4rem 1rem;
    }

    .header-info {
        display: none;
    }

    .data-table {
        font-size: 0.72rem;
    }

    .data-table th,
    .data-table td {
        padding: 0.4rem 0.5rem;
    }
}