/* ========================================
   RI-E KNOWLEDGE PLATFORM - ENTERPRISE DESIGN SYSTEM
   Premium Typography-First Architecture
   v3.0 Enterprise Quality (TR-001 Grade)
   ======================================== */

/* Global Reset & Typography Foundation */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family-body);
    background: linear-gradient(135deg, var(--color-neutral-50) 0%, rgba(241, 245, 250, 0.5) 100%);
    color: var(--color-primary-text);
    line-height: var(--line-height-relaxed);
    letter-spacing: -0.3px;
}

/* ========================================
   HEADER - Premium Enterprise Navigation
   ======================================== */

header {
    background: linear-gradient(180deg, var(--color-bg-primary) 0%, rgba(255, 255, 255, 0.98) 100%);
    border-bottom: 1px solid var(--color-border-light);
    position: sticky;
    top: 0;
    z-index: var(--z-index-sticky);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    backdrop-filter: blur(10px);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-2xl);
}

.logo {
    font-size: 28px;
    font-weight: var(--font-weight-black);
    background: linear-gradient(135deg, var(--color-primary-blue) 0%, var(--color-primary-teal) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    white-space: nowrap;
    letter-spacing: -1px;
    transition: transform var(--transition-normal);
}

.logo:hover {
    transform: translateY(-2px);
}

nav {
    display: flex;
    gap: var(--spacing-3xl);
    align-items: center;
    flex-wrap: wrap;
}

nav a {
    text-decoration: none;
    color: var(--color-secondary-text);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    transition: all var(--transition-normal);
    padding: var(--spacing-sm) var(--spacing-md);
    position: relative;
    letter-spacing: 0.5px;
}

nav a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--color-primary-blue), var(--color-primary-teal));
    transform: scaleX(0);
    transform-origin: right;
    transition: transform var(--transition-normal);
}

nav a:hover {
    color: var(--color-primary-blue);
}

nav a:hover::after {
    transform: scaleX(1);
    transform-origin: left;
}

.lang-selector {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1.5px solid var(--color-border-light);
    border-radius: var(--radius-md);
    background-color: var(--color-bg-primary);
    color: var(--color-primary-text);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    cursor: pointer;
    transition: all var(--transition-normal);
    letter-spacing: 0.3px;
}

.lang-selector:hover {
    border-color: var(--color-primary-blue);
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.12);
}

/* ========================================
   BREADCRUMB - Premium Navigation Trail
   ======================================== */

.breadcrumb {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-lg);
    font-size: var(--font-size-sm);
    color: var(--color-secondary-text);
    background-color: transparent;
    font-weight: var(--font-weight-medium);
    letter-spacing: 0.3px;
}

.breadcrumb a {
    color: var(--color-primary-blue);
    text-decoration: none;
    transition: all var(--transition-fast);
    font-weight: var(--font-weight-semibold);
    position: relative;
}

.breadcrumb a::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--color-primary-blue);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.breadcrumb a:hover {
    color: var(--color-primary-teal);
}

.breadcrumb a:hover::after {
    opacity: 1;
}

.breadcrumb span {
    color: var(--color-primary-text);
    font-weight: var(--font-weight-semibold);
}

/* ========================================
   MAIN CONTENT - Premium Layout System
   ======================================== */

.content-wrapper {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
}

main {
    background: linear-gradient(135deg, var(--color-bg-primary) 0%, rgba(241, 245, 250, 0.2) 100%);
    padding: var(--spacing-3xl);
    border-radius: var(--radius-xl);
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
    border: 1px solid rgba(37, 99, 235, 0.06);
}

/* Hero Section - Premium Typography */
.hero {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
    padding: var(--spacing-3xl) 0;
}

.hero h1 {
    font-size: 56px;
    font-weight: var(--font-weight-black);
    margin-bottom: var(--spacing-xl);
    background: linear-gradient(135deg, var(--color-primary-blue) 0%, var(--color-primary-teal) 50%, var(--color-primary-blue) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -2px;
    line-height: 1.2;
}

.hero p {
    font-size: 18px;
    color: var(--color-secondary-text);
    margin-bottom: var(--spacing-2xl);
    max-width: 680px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.6;
    letter-spacing: 0.2px;
    font-weight: var(--font-weight-medium);
}

/* Content Section - Premium Typography */
.content-section {
    margin-bottom: var(--spacing-3xl);
}

.content-section h1 {
    font-size: 42px;
    font-weight: var(--font-weight-black);
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-blue);
    letter-spacing: -1px;
    line-height: 1.3;
}

.content-section h2 {
    font-size: 32px;
    font-weight: var(--font-weight-bold);
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-blue);
    letter-spacing: -0.5px;
    line-height: 1.3;
}

.content-section h3 {
    font-size: 22px;
    font-weight: var(--font-weight-bold);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-neutral-800);
    letter-spacing: -0.3px;
    line-height: 1.4;
}

.content-section p {
    margin-bottom: var(--spacing-md);
    color: var(--color-primary-text);
    font-size: 16px;
    line-height: 1.6;
    letter-spacing: 0.2px;
    font-weight: var(--font-weight-normal);
}

/* ========================================
   NAVIGATION GRID - Premium Card Design
   ======================================== */

.navigation-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-2xl);
    margin-top: var(--spacing-3xl);
}

.nav-card {
    background: linear-gradient(135deg, var(--color-bg-primary) 0%, rgba(241, 245, 250, 0.4) 100%);
    border: 1.5px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl);
    text-decoration: none;
    color: inherit;
    transition: all var(--transition-normal);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
    position: relative;
    overflow: hidden;
}

.nav-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0) 0%, rgba(14, 165, 233, 0.05) 100%);
    opacity: 0;
    transition: opacity var(--transition-normal);
    pointer-events: none;
}

.nav-card:hover {
    border-color: var(--color-primary-blue);
    box-shadow: 0 12px 32px rgba(37, 99, 235, 0.16);
    transform: translateY(-8px);
}

.nav-card:hover::before {
    opacity: 1;
}

.nav-card-icon {
    font-size: 48px;
    margin-bottom: var(--spacing-lg);
    display: block;
    transition: transform var(--transition-normal);
}

.nav-card:hover .nav-card-icon {
    transform: scale(1.15) translateY(-4px);
}

.nav-card h2 {
    font-size: 20px;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-md);
    color: var(--color-primary-blue);
    letter-spacing: -0.3px;
    line-height: 1.3;
}

.nav-card p {
    font-size: 15px;
    color: var(--color-secondary-text);
    line-height: 1.6;
    letter-spacing: 0.2px;
    font-weight: var(--font-weight-normal);
}

/* ========================================
   LISTING PAGES - Premium List Design
   ======================================== */

.list-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-2xl);
    margin-top: var(--spacing-2xl);
}

.list-item {
    background: linear-gradient(135deg, var(--color-bg-primary) 0%, rgba(241, 245, 250, 0.3) 100%);
    border: 1.5px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl);
    text-decoration: none;
    color: inherit;
    transition: all var(--transition-normal);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.list-item::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(37, 99, 235, 0.3), transparent);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.list-item:hover {
    border-color: var(--color-primary-blue);
    box-shadow: 0 12px 32px rgba(37, 99, 235, 0.12);
    transform: translateY(-6px);
}

.list-item:hover::after {
    opacity: 1;
}

.list-item-title {
    font-size: 20px;
    font-weight: var(--font-weight-bold);
    color: var(--color-primary-blue);
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.3px;
    line-height: 1.3;
}

.list-item-meta {
    font-size: 13px;
    color: var(--color-secondary-text);
    margin-bottom: var(--spacing-md);
    font-weight: var(--font-weight-medium);
    letter-spacing: 0.3px;
    text-transform: uppercase;
}

.list-item-desc {
    font-size: 15px;
    color: var(--color-primary-text);
    line-height: 1.6;
    letter-spacing: 0.2px;
    font-weight: var(--font-weight-normal);
    flex-grow: 1;
}

/* ========================================
   METADATA BLOCK - Premium Document Info
   ======================================== */

.metadata {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-bg-secondary) 0%, rgba(241, 245, 250, 0.3) 100%);
    padding: var(--spacing-2xl);
    border-radius: var(--radius-lg);
    margin: var(--spacing-2xl) 0;
    font-size: var(--font-size-sm);
    border: 1px solid rgba(37, 99, 235, 0.08);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.metadata-item {
    display: flex;
    flex-direction: column;
}

.metadata-label {
    font-weight: var(--font-weight-bold);
    color: var(--color-primary-text);
    margin-bottom: var(--spacing-xs);
    font-size: 12px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.metadata-value {
    color: var(--color-secondary-text);
    font-weight: var(--font-weight-medium);
    letter-spacing: 0.2px;
}

/* ========================================
   SIDEBAR LAYOUT - Premium Sidebar Design
   ======================================== */

.sidebar-wrapper {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: var(--spacing-2xl);
    padding: var(--spacing-lg);
}

.sidebar {
    background: linear-gradient(135deg, var(--color-bg-primary) 0%, rgba(241, 245, 250, 0.3) 100%);
    padding: var(--spacing-2xl);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
    height: fit-content;
    position: sticky;
    top: 100px;
    border: 1px solid rgba(37, 99, 235, 0.08);
}

.sidebar h3 {
    font-size: 14px;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-text);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.sidebar ul {
    list-style: none;
}

.sidebar li {
    margin-bottom: var(--spacing-md);
}

.sidebar a {
    font-size: 14px;
    color: var(--color-primary-blue);
    text-decoration: none;
    transition: all var(--transition-fast);
    font-weight: var(--font-weight-medium);
    letter-spacing: 0.2px;
    display: inline-block;
    position: relative;
}

.sidebar a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--color-primary-blue), var(--color-primary-teal));
    transition: width var(--transition-fast);
}

.sidebar a:hover {
    color: var(--color-primary-teal);
}

.sidebar a:hover::after {
    width: 100%;
}

/* ========================================
   PROGRESS BAR - Premium Scroll Indicator
   ======================================== */

.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary-blue) 0%, var(--color-primary-teal) 50%, var(--color-primary-blue) 100%);
    z-index: var(--z-index-modal);
    width: 0%;
    transition: width var(--transition-fast);
    box-shadow: 0 0 12px rgba(37, 99, 235, 0.4);
}

/* ========================================
   FOOTER - Premium Footer Design
   ======================================== */

footer {
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.5) 0%, var(--color-bg-primary) 50%);
    border-top: 1px solid var(--color-border-light);
    padding: var(--spacing-3xl) var(--spacing-lg);
    margin-top: var(--spacing-4xl);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-3xl);
    font-size: var(--font-size-sm);
    color: var(--color-secondary-text);
}

.footer-section h3 {
    font-size: 14px;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-text);
    text-transform: uppercase;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.footer-section a {
    display: block;
    margin-bottom: var(--spacing-md);
    text-decoration: none;
    color: var(--color-secondary-text);
    transition: all var(--transition-fast);
    font-weight: var(--font-weight-medium);
    letter-spacing: 0.2px;
    position: relative;
    padding-left: 0;
}

.footer-section a::before {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 1px;
    background: linear-gradient(90deg, var(--color-primary-blue), var(--color-primary-teal));
    transition: width var(--transition-fast);
}

.footer-section a:hover {
    color: var(--color-primary-blue);
}

.footer-section a:hover::before {
    width: 100%;
}

/* ========================================
   RESPONSIVE DESIGN - Premium Mobile-First
   ======================================== */

@media (max-width: 1024px) {
    .sidebar-wrapper {
        grid-template-columns: 1fr;
    }

    .sidebar {
        display: none;
    }

    .footer-content {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-2xl);
    }
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: var(--spacing-md);
        padding: var(--spacing-lg);
    }

    .logo {
        font-size: 24px;
        letter-spacing: -0.5px;
    }

    nav {
        flex-direction: column;
        width: 100%;
        gap: var(--spacing-lg);
        justify-content: center;
    }

    nav a {
        text-align: center;
        font-size: 14px;
    }

    .hero {
        padding: var(--spacing-2xl) 0;
    }

    .hero h1 {
        font-size: 36px;
        letter-spacing: -1px;
    }

    .hero p {
        font-size: 16px;
        line-height: 1.6;
    }

    .navigation-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }

    .nav-card {
        padding: var(--spacing-xl);
    }

    .list-container {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }

    .list-item {
        padding: var(--spacing-xl);
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-2xl);
    }

    main {
        padding: var(--spacing-2xl);
    }

    .content-section h1 {
        font-size: 32px;
        letter-spacing: -0.5px;
    }

    .content-section h2 {
        font-size: 24px;
    }
}

@media (max-width: 480px) {
    .header-content {
        padding: var(--spacing-md);
    }

    .logo {
        font-size: 20px;
        letter-spacing: -0.3px;
    }

    nav {
        gap: var(--spacing-md);
    }

    nav a {
        font-size: 12px;
        padding: var(--spacing-xs) var(--spacing-sm);
    }

    .hero {
        padding: var(--spacing-xl) 0;
    }

    .hero h1 {
        font-size: 28px;
        letter-spacing: -0.5px;
        margin-bottom: var(--spacing-md);
    }

    .hero p {
        font-size: 14px;
        line-height: 1.5;
    }

    .navigation-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .nav-card {
        padding: var(--spacing-lg);
    }

    .nav-card-icon {
        font-size: 40px;
        margin-bottom: var(--spacing-md);
    }

    .nav-card h2 {
        font-size: 18px;
    }

    .nav-card p {
        font-size: 14px;
    }

    .list-item {
        padding: var(--spacing-lg);
    }

    .list-item-title {
        font-size: 18px;
    }

    main {
        padding: var(--spacing-lg);
        border-radius: var(--radius-lg);
    }

    .content-section h1 {
        font-size: 26px;
        letter-spacing: -0.3px;
    }

    .content-section h2 {
        font-size: 20px;
    }

    .footer-content {
        gap: var(--spacing-lg);
    }
}

/* ========================================
   SVG ICON SYSTEM - Enterprise Icons
   ======================================== */

.icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.5;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.icon-lg {
    width: 48px;
    height: 48px;
}

.nav-card .icon-lg {
    color: var(--color-primary-blue);
    margin-bottom: var(--spacing-lg);
    transition: transform var(--transition-normal);
}

.nav-card:hover .icon-lg {
    transform: scale(1.15) translateY(-4px);
}

/* ========================================
   DARK MODE TOGGLE
   ======================================== */

.theme-toggle {
    background: none;
    border: 1.5px solid var(--color-border-light);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    cursor: pointer;
    color: var(--color-secondary-text);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-normal);
}

.theme-toggle:hover {
    border-color: var(--color-primary-blue);
    color: var(--color-primary-blue);
}

.theme-toggle .icon {
    width: 18px;
    height: 18px;
}

/* ========================================
   METADATA PANEL - Knowledge Object Info
   ======================================== */

.metadata-panel {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--spacing-lg);
    background: var(--color-bg-secondary);
    padding: var(--spacing-2xl);
    border-radius: var(--radius-lg);
    margin: var(--spacing-2xl) 0;
    border: 1px solid var(--color-border-light);
}

.metadata-item {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.metadata-label {
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-bold);
    color: var(--color-secondary-text);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.metadata-value {
    font-size: var(--font-size-sm);
    color: var(--color-primary-text);
    font-weight: var(--font-weight-medium);
}

/* ========================================
   STATUS / LIFECYCLE BADGES
   ======================================== */

.badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-semibold);
    letter-spacing: 0.3px;
}

.badge-published {
    background: rgba(16, 185, 129, 0.1);
    color: var(--color-success);
}

.badge-draft {
    background: rgba(245, 158, 11, 0.1);
    color: var(--color-warning);
}

.badge-review {
    background: rgba(59, 130, 246, 0.1);
    color: var(--color-info);
}

.badge-deprecated {
    background: rgba(107, 114, 128, 0.1);
    color: var(--color-neutral-500);
}

.badge-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: currentColor;
}

/* ========================================
   ARTICLE / REPORT VIEWER
   ======================================== */

.article {
    background: var(--color-bg-primary);
    padding: var(--spacing-3xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-card);
    border: 1px solid var(--color-border-light);
}

.article h1 {
    font-size: 36px;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-blue);
    letter-spacing: -1px;
    line-height: var(--line-height-tight);
}

.article h2 {
    font-size: 26px;
    font-weight: var(--font-weight-bold);
    margin-top: var(--spacing-3xl);
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-blue);
    letter-spacing: -0.5px;
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--color-border-light);
}

.article h3 {
    font-size: 20px;
    font-weight: var(--font-weight-semibold);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-neutral-800);
}

.article p {
    margin-bottom: var(--spacing-lg);
    font-size: var(--font-size-base);
    line-height: var(--line-height-relaxed);
    color: var(--color-primary-text);
}

.article ul,
.article ol {
    margin: var(--spacing-lg) 0;
    padding-left: var(--spacing-xl);
}

.article li {
    margin-bottom: var(--spacing-sm);
    line-height: var(--line-height-relaxed);
    color: var(--color-primary-text);
}

.article code {
    background-color: var(--color-bg-tertiary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-family: var(--font-family-mono);
    font-size: var(--font-size-sm);
}

.article pre {
    background-color: var(--color-neutral-900);
    color: var(--color-neutral-200);
    padding: var(--spacing-xl);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: var(--spacing-xl) 0;
    font-family: var(--font-family-mono);
    font-size: var(--font-size-sm);
    line-height: var(--line-height-relaxed);
}

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

.article strong {
    font-weight: var(--font-weight-bold);
    color: var(--color-neutral-900);
}

.article-flow {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    padding: var(--spacing-xl);
    margin: var(--spacing-xl) 0;
    font-family: var(--font-family-mono);
    font-size: var(--font-size-sm);
    line-height: 2;
    color: var(--color-secondary-text);
    text-align: center;
}

/* ========================================
   RELATED KNOWLEDGE
   ======================================== */

.related-knowledge {
    margin-top: var(--spacing-3xl);
    padding-top: var(--spacing-2xl);
    border-top: 1px solid var(--color-border-light);
}

.related-knowledge h3 {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-text);
}

.related-list {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.related-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    text-decoration: none;
    color: var(--color-primary-text);
    border-bottom: 1px solid var(--color-border-light);
    transition: all var(--transition-fast);
}

.related-item:hover {
    background: var(--color-bg-secondary);
    color: var(--color-primary-blue);
}

.related-type {
    font-size: 11px;
    font-family: var(--font-family-mono);
    color: var(--color-secondary-text);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    min-width: 120px;
}

.related-title {
    flex: 1;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
}

.related-arrow {
    color: var(--color-tertiary-text);
    transition: transform var(--transition-fast);
}

.related-item:hover .related-arrow {
    transform: translateX(4px);
    color: var(--color-primary-blue);
}

/* ========================================
   SEARCH INTERFACE
   ======================================== */

.search-box {
    display: flex;
    gap: var(--spacing-md);
    margin: var(--spacing-2xl) 0;
}

.search-box input {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: var(--font-size-base);
    font-family: var(--font-family-body);
    border: 1.5px solid var(--color-border-light);
    border-radius: var(--radius-md);
    background: var(--color-bg-primary);
    color: var(--color-primary-text);
    transition: all var(--transition-normal);
}

.search-box input:focus {
    outline: none;
    border-color: var(--color-primary-blue);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.search-box button {
    padding: var(--spacing-md) var(--spacing-2xl);
    background-color: var(--color-primary-blue);
    color: var(--color-bg-primary);
    border: none;
    border-radius: var(--radius-md);
    font-weight: var(--font-weight-semibold);
    font-size: var(--font-size-base);
    cursor: pointer;
    transition: all var(--transition-normal);
}

.search-box button:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

/* ========================================
   ASSISTANT INTERFACE
   ======================================== */

.assistant-interface {
    background-color: var(--color-bg-primary);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl);
    margin: var(--spacing-2xl) 0;
    min-height: 300px;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.chat-input {
    display: flex;
    gap: var(--spacing-md);
}

.chat-input input {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: var(--font-size-base);
    font-family: var(--font-family-body);
    border: 1.5px solid var(--color-border-light);
    border-radius: var(--radius-md);
    background: var(--color-bg-primary);
    color: var(--color-primary-text);
    transition: all var(--transition-normal);
}

.chat-input input:focus {
    outline: none;
    border-color: var(--color-primary-blue);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.chat-input button {
    padding: var(--spacing-md) var(--spacing-2xl);
    background-color: var(--color-primary-blue);
    color: var(--color-bg-primary);
    border: none;
    border-radius: var(--radius-md);
    font-weight: var(--font-weight-semibold);
    cursor: pointer;
    transition: all var(--transition-normal);
}

.chat-input button:hover {
    opacity: 0.9;
}

/* ========================================
   404 PAGE
   ======================================== */

.error-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
    padding: var(--spacing-lg);
}

.error-container {
    text-align: center;
    background-color: var(--color-bg-primary);
    padding: var(--spacing-3xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    max-width: 600px;
    border: 1px solid var(--color-border-light);
}

.error-code {
    font-size: 96px;
    font-weight: var(--font-weight-bold);
    color: var(--color-primary-blue);
    margin-bottom: var(--spacing-md);
    line-height: 1;
}

.error-links {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-top: var(--spacing-xl);
}

/* ========================================
   BUTTONS
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-md);
    text-decoration: none;
    font-weight: var(--font-weight-semibold);
    font-size: var(--font-size-base);
    transition: all var(--transition-normal);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: var(--color-primary-blue);
    color: var(--color-bg-primary);
}

.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: var(--color-bg-secondary);
    color: var(--color-primary-blue);
    border: 1px solid var(--color-border-light);
}

.btn-secondary:hover {
    background-color: var(--color-bg-tertiary);
    transform: translateY(-1px);
}

/* ========================================
   IN-DEVELOPMENT NOTICE
   ======================================== */

.dev-notice {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-3xl);
    text-align: center;
    margin: var(--spacing-2xl) 0;
}

.dev-notice .icon-lg {
    color: var(--color-secondary-text);
    margin-bottom: var(--spacing-lg);
}

.dev-notice h3 {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-semibold);
    color: var(--color-primary-text);
    margin-bottom: var(--spacing-md);
}

.dev-notice p {
    color: var(--color-secondary-text);
    font-size: var(--font-size-sm);
    max-width: 480px;
    margin: 0 auto;
    line-height: var(--line-height-relaxed);
}

/* ========================================
   ARTICLE RESPONSIVE
   ======================================== */

@media (max-width: 768px) {
    .article {
        padding: var(--spacing-xl);
    }

    .article h1 {
        font-size: 28px;
    }

    .article h2 {
        font-size: 22px;
    }

    .metadata-panel {
        grid-template-columns: 1fr 1fr;
        padding: var(--spacing-lg);
    }

    .search-box {
        flex-direction: column;
    }

    .chat-input {
        flex-direction: column;
    }

    .error-code {
        font-size: 64px;
    }

    .error-links {
        flex-direction: column;
        align-items: center;
    }

    .related-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-xs);
    }

    .related-type {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .metadata-panel {
        grid-template-columns: 1fr;
    }
}