/* Elementary Bitcoin - Classic Mathematics Textbook Style */

:root {
    --text-color: #1a1a1a;
    --bg-color: #fefefe;
    --accent-color: #8b4513;
    --secondary-color: #2f4f4f;
    --light-border: #ddd;
    --theorem-bg: #f8f5f0;
    --definition-bg: #f0f5f8;
    --example-bg: #f5f8f0;
    --exercise-bg: #fff8f0;
    --proof-border: #666;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, Georgia, serif;
    font-size: 18px;
    line-height: 1.7;
    color: var(--text-color);
    background: var(--bg-color);
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

/* Headers */
h1, h2, h3, h4 {
    font-weight: normal;
    color: var(--secondary-color);
    margin-top: 2rem;
}

h1 {
    font-size: 2.5rem;
    text-align: center;
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: 1rem;
    margin-bottom: 0.5rem;
}

h2 {
    font-size: 1.8rem;
    border-bottom: 1px solid var(--light-border);
    padding-bottom: 0.5rem;
}

h3 {
    font-size: 1.4rem;
    font-style: italic;
}

/* Book header */
.book-header {
    text-align: center;
    margin-bottom: 3rem;
}

.book-header .subtitle {
    font-size: 1.3rem;
    font-style: italic;
    color: var(--secondary-color);
    margin: 0.5rem 0;
}

.book-header .author {
    font-size: 1rem;
    color: #666;
}

/* Chapter header */
.chapter-header {
    text-align: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--light-border);
}

.chapter-number {
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--accent-color);
    display: block;
    margin-bottom: 0.5rem;
}

.chapter-title {
    font-size: 2rem;
    margin: 0;
}

.chapter-epigraph {
    font-style: italic;
    color: #666;
    margin-top: 1rem;
    padding: 0 2rem;
}

/* Table of Contents */
.table-of-contents h2 {
    text-align: center;
    font-size: 1.5rem;
}

.part h3 {
    font-size: 1.1rem;
    color: var(--accent-color);
    margin-top: 2rem;
    margin-bottom: 0.5rem;
}

.chapters {
    list-style: none;
    padding-left: 0;
}

.chapters li {
    margin: 0.8rem 0;
    padding-left: 2rem;
    position: relative;
}

.chapters li::before {
    content: counter(list-item) ".";
    position: absolute;
    left: 0;
    color: var(--secondary-color);
}

.chapters a {
    color: var(--text-color);
    text-decoration: none;
    border-bottom: 1px dotted var(--accent-color);
}

.chapters a:hover {
    color: var(--accent-color);
}

.chapter-desc {
    display: block;
    font-size: 0.85rem;
    color: #666;
    font-style: italic;
    margin-top: 0.2rem;
}

/* Mathematical blocks */
.definition, .theorem, .lemma, .corollary, .proposition {
    margin: 1.5rem 0;
    padding: 1rem 1.5rem;
    border-left: 4px solid var(--accent-color);
}

.definition {
    background: var(--definition-bg);
    border-left-color: #4a90d9;
}

.theorem, .lemma, .corollary, .proposition {
    background: var(--theorem-bg);
}

.definition-title, .theorem-title {
    font-weight: bold;
    font-variant: small-caps;
    margin-bottom: 0.5rem;
}

.definition-title::after, .theorem-title::after {
    content: ".";
}

/* Examples */
.example {
    margin: 1.5rem 0;
    padding: 1rem 1.5rem;
    background: var(--example-bg);
    border-left: 4px solid #5a8f5a;
}

.example-title {
    font-weight: bold;
    font-variant: small-caps;
    color: #3a6f3a;
}

/* Proofs */
.proof {
    margin: 1rem 0;
    padding-left: 1rem;
    border-left: 2px solid var(--proof-border);
}

.proof-title {
    font-style: italic;
    font-weight: normal;
}

.proof-title::before {
    content: "Proof. ";
    font-style: italic;
}

.qed {
    float: right;
    font-size: 1rem;
}

.qed::after {
    content: "◻";
}

/* Exercises */
.exercises {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid var(--light-border);
}

.exercises h3 {
    font-size: 1.2rem;
    font-style: normal;
    font-variant: small-caps;
}

.exercise {
    margin: 1rem 0;
    padding: 0.8rem 1rem;
    background: var(--exercise-bg);
    border-left: 3px solid #d4a574;
}

.exercise-number {
    font-weight: bold;
    color: var(--accent-color);
}

/* Code and mathematical notation */
code {
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9em;
    background: #f4f4f4;
    padding: 0.1em 0.3em;
    border-radius: 2px;
}

pre {
    background: #2d2d2d;
    color: #f8f8f2;
    padding: 1rem;
    border-radius: 4px;
    overflow-x: auto;
    font-size: 0.9rem;
    line-height: 1.4;
}

/* Mathematical expressions - inline */
.math {
    font-family: 'Times New Roman', Times, serif;
    font-style: italic;
}

/* SVG diagrams */
.diagram {
    display: block;
    margin: 2rem auto;
    max-width: 100%;
}

.diagram-caption {
    text-align: center;
    font-size: 0.9rem;
    color: #666;
    font-style: italic;
    margin-top: 0.5rem;
}

figure {
    margin: 2rem 0;
    text-align: center;
}

figcaption {
    font-size: 0.9rem;
    color: #666;
    font-style: italic;
    margin-top: 0.5rem;
}

/* Remarks and notes */
.remark {
    margin: 1rem 0;
    padding: 0.8rem 1rem;
    background: #fafafa;
    border: 1px dashed #ccc;
    font-size: 0.95rem;
}

.remark-title {
    font-style: italic;
    color: #666;
}

/* Navigation */
.chapter-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 3rem;
    padding-top: 1rem;
    border-top: 1px solid var(--light-border);
}

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

.chapter-nav a:hover {
    text-decoration: underline;
}

/* Blockquotes */
blockquote {
    margin: 1.5rem 2rem;
    padding-left: 1rem;
    border-left: 3px solid var(--light-border);
    color: #555;
    font-style: italic;
}

/* Lists */
ul, ol {
    margin: 1rem 0;
    padding-left: 2rem;
}

li {
    margin: 0.3rem 0;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
}

th, td {
    border: 1px solid var(--light-border);
    padding: 0.5rem;
    text-align: left;
}

th {
    background: #f5f5f5;
    font-weight: normal;
    font-variant: small-caps;
}

/* Footer */
footer {
    margin-top: 3rem;
    padding-top: 1rem;
    border-top: 1px solid var(--light-border);
    text-align: center;
}

.preface-note {
    font-size: 0.95rem;
    color: #666;
    max-width: 600px;
    margin: 0 auto;
}

/* Responsive */
@media (max-width: 600px) {
    body {
        padding: 1rem;
        font-size: 16px;
    }

    h1 {
        font-size: 1.8rem;
    }

    .definition, .theorem, .example, .proof {
        padding: 0.8rem;
        margin: 1rem -0.5rem;
    }
}