:root {
    --primary: #6366f1;
    --primary-light: #818cf8;
    --bg: #f8fafc;
    --text: #0f172a;
    --text-muted: #475569;
    --border: #e2e8f0;
    --card-bg: #ffffff;
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #020617;
        --text: #f1f5f9;
        --text-muted: #94a3b8;
        --border: #1e293b;
        --card-bg: #0f172a;
    }
}

* { box-sizing: border-box; }

body {
    font-family: var(--font-main);
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.8;
    margin: 0;
    -webkit-font-smoothing: antialiased;
}

/* Progress Bar */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: linear-gradient(to right, var(--primary), var(--primary-light));
    width: 0%;
    z-index: 2000;
    transition: width 0.1s ease;
}

/* Layout */
.page-wrapper {
    display: grid;
    grid-template-columns: 1fr minmax(0, 800px) 1fr;
    gap: 2rem;
}

/* Header Area */
.article-header {
    grid-column: 1 / -1;
    padding: 6rem 1.5rem 4rem;
    background: linear-gradient(135deg, var(--card-bg) 0%, var(--bg) 100%);
    border-bottom: 1px solid var(--border);
    text-align: center;
}

.header-content {
    max-width: 900px;
    margin: 0 auto;
}

.post-category {
    display: inline-block;
    background: var(--primary);
    color: white;
    padding: 0.25rem 1rem;
    border-radius: 99px;
    font-weight: 700;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 1.5rem;
}

h1 {
    font-size: 4rem;
    font-weight: 800;
    letter-spacing: -0.04em;
    line-height: 1.1;
    margin: 0 0 2rem;
}

.post-meta-top {
    display: flex;
    justify-content: center;
    gap: 2rem;
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.9375rem;
}

/* Main Content Area */
.main-content {
    grid-column: 2;
    padding: 4rem 0;
}

.article-body {
    font-size: 1.25rem;
}

.article-body h2 {
    font-size: 2.25rem;
    font-weight: 800;
    margin: 4rem 0 1.5rem;
    letter-spacing: -0.02em;
}

.article-body p {
    margin-bottom: 2rem;
}

.article-body ul, .article-body ol {
    margin-bottom: 2rem;
    padding-left: 1.5rem;
}

.article-body li {
    margin-bottom: 0.75rem;
}

/* Callout Box */
.info-callout {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-left: 6px solid var(--primary);
    padding: 2.5rem;
    border-radius: 12px;
    margin: 4rem 0;
    box-shadow: 0 10px 15px -3px rgba(0,0,0,0.05);
}

/* Sidebar Elements (Hidden on small screens) */
.sidebar-left {
    grid-column: 1;
    padding-top: 4rem;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    position: sticky;
    top: 4rem;
    height: fit-content;
}

.back-btn-new {
    text-decoration: none;
    color: var(--text);
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    border-radius: 8px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    transition: all 0.2s;
}

.back-btn-new:hover {
    transform: translateX(-4px);
    border-color: var(--primary);
}

/* Footer Section */
.article-footer {
    grid-column: 2;
    padding: 4rem 0;
    border-top: 1px solid var(--border);
    margin-top: 4rem;
}

.author-box {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--border);
}

.author-avatar {
    width: 64px;
    height: 64px;
    background: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 800;
    color: white;
}

@media (max-width: 1100px) {
    .page-wrapper {
        grid-template-columns: 1fr;
        padding: 0 1.5rem;
    }
    .main-content, .article-header, .article-footer {
        grid-column: 1;
    }
    .sidebar-left {
        display: none;
    }
    h1 { font-size: 2.5rem; }
}