/* ============================================
   Style Variant: Light (AWS Blogs-inspired)
   Enterprise editorial, information-first, polished
   ============================================ */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;700&display=swap');

:root {
    --page-bg: #FFFFFF;
    --utility-nav-bg: #161D26;
    --utility-nav-alt: #232B37;
    --heading-text: #161D26;
    --body-text: #333333;
    --muted-text: #5F6B7A;
    --border-subtle: #D5DBDB;
    --divider: #EAEDED;
    --link-primary: #006CE0;
    --link-hover: #004B97;
    --focus-ring: #006CE0;
    --cta-fill: #0EA5A4;
    --cta-hover: #0B7D7C;
    --cta-text: #FFFFFF;
    --surface-card: #FAFAFA;
    --font-display: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    --font-mono: 'JetBrains Mono', Consolas, monospace;
    --font-size-base: 15px;
    --line-height-base: 1.65;
    --max-content-width: 1100px;
    --sidebar-width: 250px;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
}

/* ============================================
   Reset & Base
   ============================================ */
*, *::before, *::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-body);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--body-text);
    background-color: var(--page-bg);
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
    font-family: var(--font-display);
    color: var(--heading-text);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    line-height: 1.25;
    font-weight: 700;
}

h1 {
    font-size: clamp(1.75rem, 4vw, 2.25rem);
    margin-top: 0;
}

h2 {
    font-size: 1.35rem;
    font-weight: 600;
    border-bottom: 1px solid var(--divider);
    padding-bottom: var(--spacing-sm);
}

h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--heading-text);
}

h4 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--muted-text);
}

h1:focus {
    outline: 2px solid var(--focus-ring);
    outline-offset: 4px;
}

p {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    max-width: 72ch;
}

ul, ol {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-lg);
    max-width: 72ch;
}

li {
    margin-bottom: var(--spacing-sm);
}

a {
    color: var(--link-primary);
    text-decoration: none;
    transition: color 0.2s;
}

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

a:focus {
    outline: 2px solid var(--focus-ring);
    outline-offset: 2px;
}

strong {
    font-weight: 600;
}

/* ============================================
   Layout (sidebar + content)
   ============================================ */
.layout {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: var(--sidebar-width);
    min-width: var(--sidebar-width);
    background-color: var(--utility-nav-bg);
    padding: var(--spacing-lg) 0;
    position: sticky;
    top: 0;
    height: 100vh;
    overflow-y: auto;
}

.content {
    flex: 1;
    padding: var(--spacing-xl) var(--spacing-xl);
    overflow-y: auto;
    height: 100vh;
    max-width: var(--max-content-width);
}

/* ============================================
   Navigation Tree
   ============================================ */
.sidebar-brand {
    padding: 1rem 1.2rem 1.5rem;
    font-size: 1.2rem;
    letter-spacing: 0.15em;
    color: #FFFFFF;
}

.nav-tree {
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-tree ul {
    list-style: none;
    margin: 0;
    padding: 0;
    padding-left: var(--spacing-md);
}

.nav-group {
    margin-bottom: 2px;
}

.nav-group-label {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    font-weight: 600;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: #8899AA;
    user-select: none;
}

.nav-link {
    display: block;
    padding: 0.6rem var(--spacing-md);
    color: #C8D2DC;
    text-decoration: none;
    border-left: 3px solid transparent;
    transition: background-color 0.2s, border-color 0.2s, color 0.2s;
    font-size: 0.875rem;
}

.nav-link:hover {
    background-color: var(--utility-nav-alt);
    color: #FFFFFF;
}

.nav-link:focus {
    outline: 2px solid var(--cta-fill);
    outline-offset: -2px;
}

.nav-link.active {
    background-color: var(--utility-nav-alt);
    border-left-color: var(--cta-fill);
    font-weight: 600;
    color: #FFFFFF;
}

/* ============================================
   Content Area & Typography
   ============================================ */
.page {
    max-width: 850px;
}

.page > h1 {
    color: var(--heading-text);
    margin-bottom: var(--spacing-lg);
}

/* ============================================
   Code Blocks & Tables
   ============================================ */
code {
    font-family: var(--font-mono);
    font-size: 0.85em;
    background-color: var(--surface-card);
    color: var(--heading-text);
    padding: 0.2em 0.4em;
    border-radius: 3px;
    border: 1px solid var(--border-subtle);
}

pre {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.6;
    background-color: var(--surface-card);
    border: 1px solid var(--border-subtle);
    border-radius: 4px;
    padding: var(--spacing-md);
    overflow-x: auto;
    max-width: 100%;
    margin-bottom: var(--spacing-lg);
    color: var(--body-text);
}

pre code {
    background: none;
    border: none;
    padding: 0;
    font-size: inherit;
    color: inherit;
}

table {
    width: 100%;
    max-width: 100%;
    border-collapse: collapse;
    margin-bottom: var(--spacing-lg);
    font-size: 0.875rem;
}

th, td {
    padding: 0.6rem var(--spacing-md);
    border: 1px solid var(--border-subtle);
    text-align: left;
    vertical-align: top;
}

th {
    background-color: var(--divider);
    font-weight: 600;
    color: var(--heading-text);
    font-size: 0.8rem;
}

td {
    color: var(--body-text);
}

tr:nth-child(even) {
    background-color: var(--surface-card);
}

/* ============================================
   7. Diagrams (pre-formatted ASCII art)
   ============================================ */
pre.ascii-art {
    font-family: Consolas, "Courier New", monospace;
    font-size: 0.8rem;
    line-height: 1.3;
    white-space: pre;
    overflow-x: auto;
    color: var(--muted-text);
}

/* ============================================
   Utility
   ============================================ */
.page[hidden] {
    display: none;
}

/* ============================================
   Reduced Motion
   ============================================ */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        transition-duration: 0s !important;
        animation-duration: 0s !important;
    }
    html {
        scroll-behavior: auto;
    }
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 900px) {
    .sidebar {
        width: 200px;
        min-width: 200px;
    }
}

@media (max-width: 768px) {
    .layout {
        flex-direction: column;
    }
    .sidebar {
        width: 100%;
        min-width: 100%;
        height: auto;
        position: static;
        border-bottom: 1px solid var(--border-subtle);
        padding: var(--spacing-md) 0;
    }
    .content {
        height: auto;
        padding: var(--spacing-lg);
    }
    .nav-tree ul {
        display: flex;
        flex-wrap: wrap;
        padding-left: 0;
    }
    .nav-link {
        border-left: none;
        border-bottom: 3px solid transparent;
    }
    .nav-link.active {
        border-left-color: transparent;
        border-bottom-color: var(--cta-fill);
    }
}