:root {
    --bg-primary: #0A1A10;
    --bg-code: #0D1F14;
    --bg-hover: #132B1B;
    --text-primary: #C8D9CC;
    --text-heading: #E2EDE5;
    --accent-primary: #2D5F3F;
    --accent-secondary: #3A9D5E;
    --accent-gold: #B8A044;
    --accent-syntax: #7EC89A;
    --text-muted: #5A8A6A;
    --border-color: #1A3324;
    --font-display: 'JetBrains Mono', monospace;
    --font-body: 'Source Serif 4', Georgia, serif;
    --font-code: 'Fira Code', monospace;
    --font-margin: 'JetBrains Mono', monospace;
}

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

html {
    font-size: 16px;
    scroll-snap-type: y proximity;
    scroll-behavior: smooth;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-body);
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
}

/* Background watermark SVG */
.bg-watermark-svg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

/* Preamble - Title Page */
.preamble {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    scroll-snap-align: start;
    position: relative;
    z-index: 1;
}

.preamble-title {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(1.8rem, 3vw, 2.8rem);
    color: var(--text-heading);
    letter-spacing: 0.02em;
    margin-bottom: 1.5rem;
}

.preamble-sig {
    font-family: var(--font-display);
    font-weight: 300;
    font-size: 0.9rem;
    color: var(--text-muted);
    letter-spacing: 0.02em;
}

/* Lambda Dividers */
.lambda-divider {
    text-align: center;
    font-size: 48px;
    color: var(--accent-primary);
    padding: 3rem 0;
    user-select: none;
    position: relative;
    z-index: 1;
}

/* Proof Blocks - Content Sections */
.proof-block {
    max-width: 680px;
    margin: 0 auto;
    padding: 0 2rem 120px;
    scroll-snap-align: start;
    position: relative;
    z-index: 1;
}

/* Margin Annotations */
.margin-annotation {
    display: none;
}

@media (min-width: 1200px) {
    .margin-annotation {
        display: block;
        position: absolute;
        left: -220px;
        top: 0;
        width: 180px;
    }

    .margin-note {
        font-family: var(--font-margin);
        font-weight: 300;
        font-size: 0.75rem;
        color: var(--text-muted);
        opacity: 0.7;
        line-height: 1.5;
        position: sticky;
        top: 2rem;
        display: block;
    }
}

/* Section Headings */
.section-heading {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(1.8rem, 3vw, 2.8rem);
    color: var(--text-heading);
    letter-spacing: 0.02em;
    margin-bottom: 1.5rem;
}

/* Body Text */
.body-text {
    font-family: var(--font-body);
    font-weight: 400;
    font-size: clamp(1rem, 1.1vw + 0.4rem, 1.15rem);
    line-height: 1.75;
    color: var(--text-primary);
    margin-bottom: 1.5em;
}

/* Inline Code */
.inline-code {
    font-family: var(--font-code);
    font-size: 0.88em;
    color: var(--accent-syntax);
    background: var(--bg-code);
    padding: 0.15em 0.4em;
    border-radius: 2px;
}

/* Code Blocks */
.code-block {
    background-color: var(--bg-code);
    padding: 1.5rem;
    padding-left: 24px;
    border-left: 2px solid var(--accent-primary);
    margin: 2rem 0;
    overflow-x: auto;
    transition: filter 0.2s ease;
}

.code-block:hover {
    filter: brightness(1.1);
}

.code-block:hover .kw,
.code-block:hover .fn,
.code-block:hover .type,
.code-block:hover .op,
.code-block:hover .comment,
.code-block:hover .str,
.code-block:hover .num {
    transition: color 0.2s ease;
}

.code-block:hover .kw {
    color: #8ed8aa;
}

.code-block:hover .fn {
    color: #8ed8aa;
}

.code-block:hover .type {
    color: #4aad6e;
}

.code-block:hover .op {
    color: #f2fdf5;
}

.code-block:hover .comment {
    color: #6a9a7a;
}

.code-block:hover .str,
.code-block:hover .num {
    color: #c8b054;
}

.code-block pre {
    margin: 0;
    font-family: var(--font-code);
    font-size: 0.9em;
    line-height: 1.75;
}

.code-block code {
    font-family: inherit;
    color: var(--text-primary);
}

/* Line Numbers */
.ln {
    color: var(--border-color);
    opacity: 0.5;
    user-select: none;
    display: inline-block;
    width: 2.5ch;
    text-align: right;
    margin-right: 1.5ch;
}

/* Syntax Highlighting */
.kw {
    color: var(--accent-syntax);
    font-weight: 700;
}

.type {
    color: var(--accent-secondary);
}

.fn {
    color: var(--accent-syntax);
}

.op {
    color: var(--text-heading);
}

.str {
    color: var(--accent-gold);
}

.num {
    color: var(--accent-gold);
}

.comment {
    color: var(--text-muted);
    font-style: italic;
}

/* Commutative Diagram */
.commutative-diagram {
    max-width: 400px;
    margin: 0 auto;
    padding: 2rem 2rem 4rem;
    opacity: 0.35;
    position: relative;
    z-index: 1;
}

.category-diagram {
    width: 100%;
    height: auto;
}

/* Colophon Footer */
.colophon {
    max-width: 680px;
    margin: 0 auto;
    padding: 4rem 2rem 8rem;
    position: relative;
    z-index: 1;
}

.colophon-text {
    font-family: var(--font-display);
    font-weight: 300;
    font-size: 0.75rem;
    color: var(--text-muted);
    letter-spacing: 0.02em;
    margin-bottom: 0.75rem;
}

.colophon-comment {
    color: var(--text-muted);
    font-style: italic;
}

.colophon-meta {
    font-family: var(--font-display);
    font-weight: 300;
    font-size: 0.75rem;
    color: var(--border-color);
    letter-spacing: 0.02em;
    margin-bottom: 0.5rem;
}

.colophon-links {
    font-family: var(--font-display);
    font-weight: 300;
    font-size: 0.75rem;
    letter-spacing: 0.02em;
}

.colophon-link {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

.colophon-link:hover {
    color: var(--accent-secondary);
}

.colophon-sep {
    color: var(--border-color);
    margin: 0 0.4em;
}

/* Fade Reveal Animation */
.fade-reveal {
    opacity: 0;
    transition: opacity 0.6s ease-out;
}

.fade-reveal.visible {
    opacity: 1;
}

/* Responsive */
@media (max-width: 768px) {
    .proof-block {
        padding: 0 1.5rem 80px;
    }

    .preamble-title {
        font-size: 1.8rem;
    }

    .code-block {
        padding: 1rem;
        font-size: 0.85em;
    }

    .commutative-diagram {
        max-width: 280px;
    }
}

@media (max-width: 480px) {
    .body-text {
        font-size: 0.95rem;
    }

    .lambda-divider {
        font-size: 36px;
    }

    .colophon {
        padding: 3rem 1.5rem 6rem;
    }
}