:root {
    /* STRICT COLORS - NON-NEGOTIABLE */
    --bg-color: #FFFFFF;
    --text-color: #000000;
    --link-color: #1a0dab;
    --link-visited: #660099;
    --accent-color: #555555;
    --border-color: #dddddd;
    --code-bg: #f5f5f5;

    /* FONTS */
    --font-main: Arial, Helvetica, sans-serif;
}

/* RESET & BASE */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    line-height: 1.6;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-main);
    -webkit-font-smoothing: antialiased;
}

body {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

/* TYPOGRAPHY */
h1, h2, h3, h4, h5, h6 {
    margin-top: 1.5em;
    margin-bottom: 0.5em;
    font-weight: bold;
    color: var(--text-color);
    line-height: 1.2;
}

h1 { font-size: 2.25rem; margin-top: 0; }
h2 { font-size: 1.75rem; border-bottom: 1px solid var(--border-color); padding-bottom: 10px; }
h3 { font-size: 1.5rem; }

p {
    margin-bottom: 1.25em;
    max-width: 70ch; /* Optimal reading width */
}

a {
    color: var(--link-color);
    text-decoration: underline;
}

a:visited {
    color: var(--link-visited);
}

a:hover {
    text-decoration: none;
}

ul, ol {
    margin-bottom: 1.25em;
    padding-left: 40px;
}

li {
    margin-bottom: 0.5em;
}

/* LAYOUT STRUCTURE */
header {
    border-bottom: 4px solid var(--text-color);
    padding-bottom: 20px;
    margin-bottom: 40px;
}

.site-title {
    font-size: 1.5rem;
    font-weight: bold;
    text-transform: uppercase;
    text-decoration: none;
    color: var(--text-color);
    letter-spacing: 1px;
}

nav ul {
    list-style: none;
    padding: 0;
    margin-top: 10px;
}

nav li {
    display: inline-block;
    margin-right: 20px;
}

/* BLOG POST STRUCTURE */
.metadata-block {
    font-size: 0.9rem;
    color: var(--accent-color);
    margin-bottom: 30px;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    padding: 10px 0;
}

.metadata-block span {
    margin-right: 20px;
    display: inline-block;
}

/* TABLE OF CONTENTS */
.toc {
    background-color: var(--code-bg);
    padding: 20px;
    margin-bottom: 30px;
    border: 1px solid var(--border-color);
}

.toc h3 {
    margin-top: 0;
    font-size: 1.2rem;
}

.toc ul {
    margin-bottom: 0;
}

/* AUTHOR AUTHORITY BLOCK */
.authority-block {
    margin-top: 60px;
    padding: 30px;
    background-color: #f9f9f9;
    border-left: 5px solid var(--text-color);
    border: 1px solid var(--border-color);
}

.authority-block h3 {
    margin-top: 0;
    font-size: 1.25rem;
}

.authority-content {
    display: flex;
    gap: 20px;
    align-items: flex-start;
}

.author-image {
    width: 80px;
    height: 80px;
    background-color: #ddd;
    border-radius: 50%;
    flex-shrink: 0;
}

.authority-text p {
    margin-bottom: 10px;
    font-size: 0.95rem;
}

footer {
    margin-top: 80px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--accent-color);
    text-align: center;
}

/* UTILITIES */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* RESPONSIVE */
@media (max-width: 600px) {
    body {
        padding: 15px;
    }
    
    h1 { font-size: 1.8rem; }
    h2 { font-size: 1.5rem; }
    
    .authority-content {
        flex-direction: column;
    }
}