/* === BLACK AND WHITE BOLD THEME === */

body {
    background-color: #ffffff;
    color: #000000;
    font-family: 'Georgia', 'Times New Roman', serif;
    margin: 0;
    padding: 0;
    line-height: 1.8;
}

/* Header */
header {
    max-width: 1200px;
    margin: 0 auto;
    padding: 60px 20px 30px;
    border-bottom: 4px solid #000000;
}

header h1 {
    font-size: 3em;
    margin: 0;
    color: #000000;
    font-weight: bold;
    letter-spacing: -1px;
}

header p {
    color: #000000;
    font-style: italic;
    margin: 5px 0 25px;
    font-size: 1.1em;
}

nav a {
    margin-right: 30px;
    color: #000000;
    text-decoration: none;
    font-size: 1.1em;
    font-weight: bold;
    border-bottom: 2px solid transparent;
}

nav a:hover {
    border-bottom: 2px solid #000000;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 60px 20px;
    display: grid;
    grid-template-columns: 1fr 280px;
    gap: 60px;
}

@media (max-width: 900px) {
    .container {
        grid-template-columns: 1fr;
    }
}

/* Content */
.content {
    min-width: 0;
}

/* Sidebar */
.sidebar {
    position: sticky;
    top: 40px;
    align-self: start;
}

.sidebar-widget {
    border: 2px solid #000000;
    padding: 20px;
    margin-bottom: 30px;
}

.sidebar-widget h3 {
    color: #000000;
    margin-top: 0;
    border-bottom: 2px solid #000000;
    padding-bottom: 10px;
    font-weight: bold;
}

.sidebar-widget ul {
    list-style: none;
    padding: 0;
}

.sidebar-widget li {
    margin-bottom: 10px;
    border-bottom: 1px solid #000000;
    padding-bottom: 5px;
}

.sidebar-widget li:last-child {
    border-bottom: none;
}

/* Post Grid */
.post-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

/* Post Card */
.post-card {
    border: 3px solid #000000;
    padding: 25px;
    transition: background-color 0.2s ease;
}

.post-card:hover {
    background-color: #000000;
}

.post-card:hover h2 a,
.post-card:hover .post-date,
.post-card:hover .post-excerpt,
.post-card:hover .read-more {
    color: #ffffff;
}

.post-card h2 {
    margin-top: 0;
    font-size: 1.4em;
    border-bottom: none;
}

.post-card h2 a {
    color: #000000;
    text-decoration: none;
    font-weight: bold;
}

.post-date {
    color: #000000;
    font-size: 0.85em;
    margin: 5px 0 15px;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.post-excerpt {
    color: #000000;
    font-size: 0.95em;
    margin-bottom: 15px;
}

.read-more {
    color: #000000;
    font-size: 0.9em;
    text-decoration: none;
    font-weight: bold;
    text-transform: uppercase;
}

/* Single Post */
.single-post {
    max-width: 100%;
}

.single-post h1 {
    font-size: 2.5em;
    color: #000000;
    font-weight: bold;
    letter-spacing: -0.5px;
}

.single-post hr {
    border: none;
    border-top: 4px solid #000000;
    margin: 20px 0 30px;
}

/* Code */
code {
    background-color: #f0f0f0;
    padding: 2px 6px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    color: #000000;
    border: 1px solid #000000;
}

pre {
    background-color: #f0f0f0;
    padding: 15px;
    overflow-x: auto;
    border: 2px solid #000000;
}

/* Blockquotes (Theorems, Proofs) */
blockquote {
    border-left: 6px solid #000000;
    margin: 1.5em 0;
    padding: 10px 20px;
    background-color: #f0f0f0;
    font-style: italic;
}

/* Links */
a {
    color: #000000;
    text-decoration: none;
    border-bottom: 2px solid #000000;
    font-weight: bold;
}

a:hover {
    background-color: #000000;
    color: #ffffff;
}

/* Headings */
h1, h2, h3, h4 {
    color: #000000;
    font-weight: bold;
}

h2 {
    border-bottom: 3px solid #000000;
    padding-bottom: 10px;
    margin-top: 2.5em;
    font-size: 1.8em;
}

h3 {
    font-size: 1.4em;
    margin-top: 2em;
}

/* KaTeX (Math) */
.katex {
    font-size: 1.1em;
    color: #000000;
}

.katex-display {
    background-color: #f0f0f0;
    padding: 15px;
    overflow-x: auto;
    border: 2px solid #000000;
    margin: 1.5em 0;
}

/* Footer */
footer {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
    border-top: 4px solid #000000;
    text-align: center;
    color: #000000;
    font-size: 0.85em;
    font-weight: bold;
}

/* Selection */
::selection {
    background-color: #000000;
    color: #ffffff;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5em 0;
    font-size: 0.95em;
}

th, td {
    border: 2px solid #000000;
    padding: 10px 15px;
    text-align: left;
}

th {
    background-color: #000000;
    color: #ffffff;
    font-weight: bold;
}

tr:nth-child(even) {
    background-color: #f5f5f5;
}

tr:hover {
    background-color: #e0e0e0;
}