/* ================================================
   GUIDE ARTICLE - Editorial Craft Design
   ================================================ */

/* CSS Variables - Shared Design System */
:root {
    /* Colors */
    --color-bg: #0f0f23;
    --color-bg-elevated: #16162d;
    --color-surface: #1e1e3a;
    --color-cream: #faf8f5;
    --color-cream-muted: #e8e6e1;
    --color-accent: #e8ff47;
    --color-accent-hover: #d4eb3a;
    --color-text: #faf8f5;
    --color-text-muted: #a0a0b8;
    --color-border: rgba(255, 255, 255, 0.08);

    /* Typography */
    --font-display: 'Sora', sans-serif;
    --font-body: 'DM Sans', sans-serif;

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2.5rem;
    --space-xl: 4rem;
    --space-2xl: 6rem;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 32px;
}

/* Reset */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Noise Texture Overlay */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
    opacity: 0.03;
    pointer-events: none;
    z-index: 1000;
}

/* ================================================
   NAVIGATION
   ================================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: var(--space-sm) 0;
    transition: var(--transition-base);
}

.navbar::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--color-bg);
    opacity: 0;
    transition: var(--transition-base);
    border-bottom: 1px solid transparent;
}

.navbar.scrolled::before {
    opacity: 0.95;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom-color: var(--color-border);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    z-index: 1;
}

.nav-logo {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text);
    text-decoration: none;
    letter-spacing: -0.02em;
    transition: var(--transition-fast);
}

.nav-logo:hover {
    color: var(--color-accent);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--space-xs);
    align-items: center;
}

.nav-item {
    position: relative;
}

.nav-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-family: var(--font-body);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-muted);
    text-decoration: none;
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
    cursor: pointer;
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-text);
    background: var(--color-surface);
}

/* Dropdown */
.dropdown-toggle::after {
    content: '';
    width: 0;
    height: 0;
    border-left: 4px solid transparent;
    border-right: 4px solid transparent;
    border-top: 5px solid currentColor;
    opacity: 0.6;
    transition: var(--transition-fast);
}

.nav-dropdown:hover .dropdown-toggle::after {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%) translateY(8px);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    min-width: 200px;
    padding: var(--space-xs);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-base);
    list-style: none;
}

.nav-dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.dropdown-menu li a {
    display: block;
    padding: 12px 16px;
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.dropdown-menu li a:hover,
.dropdown-menu li a.active {
    color: var(--color-text);
    background: rgba(255, 255, 255, 0.05);
}

/* ================================================
   LAYOUT
   ================================================ */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    padding-top: 70px;
}

/* ================================================
   PAGE HEADER
   ================================================ */
.page-header {
    text-align: center;
    padding: var(--space-lg) 0 var(--space-md);
}

.page-header .title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--color-text);
    margin: 0 0 var(--space-xs);
}

.page-header .last-updated {
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

/* ================================================
   MAIN CONTENT
   ================================================ */
.main {
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-lg) var(--space-xl);
    margin-bottom: var(--space-lg);
    position: relative;
    overflow: hidden;
}

/* Subtle glow effect */
.main::before {
    content: '';
    position: absolute;
    top: -100px;
    right: -100px;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(232, 255, 71, 0.08) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

/* ================================================
   ARTICLE CONTENT
   ================================================ */
.article-content {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.article-content .intro {
    font-size: 1.1rem;
    color: var(--color-text);
    margin-bottom: var(--space-md);
    line-height: 1.7;
}

.article-content p {
    font-size: 1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--space-md);
    line-height: 1.7;
}

.article-content h2 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text);
    margin-top: var(--space-xl);
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-xs);
    border-bottom: 2px solid var(--color-accent);
    letter-spacing: -0.01em;
}

.article-content h3 {
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--color-text);
    margin-top: var(--space-lg);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.01em;
}

.article-content h4 {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-text);
    margin-top: var(--space-md);
    margin-bottom: var(--space-xs);
}

.article-content ul,
.article-content ol {
    margin-bottom: var(--space-md);
    padding-left: var(--space-md);
}

.article-content li {
    font-size: 1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--space-xs);
    line-height: 1.6;
}

.article-content li::marker {
    color: var(--color-accent);
}

.article-content a {
    color: var(--color-accent);
    text-decoration: none;
    transition: var(--transition-fast);
}

.article-content a:hover {
    color: var(--color-accent-hover);
    text-decoration: underline;
}

/* ================================================
   FOOTER
   ================================================ */
.footer {
    padding: var(--space-lg) 0;
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.footer-copyright {
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

.footer-nav {
    display: flex;
    gap: var(--space-md);
}

.footer-nav a {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    text-decoration: none;
    transition: var(--transition-fast);
}

.footer-nav a:hover {
    color: var(--color-text);
}

.footer-nav a.active {
    color: var(--color-accent);
}

/* ================================================
   RESPONSIVE DESIGN
   ================================================ */
@media (max-width: 768px) {
    :root {
        --space-lg: 1.5rem;
        --space-xl: 2.5rem;
    }

    .container {
        padding: 0 var(--space-sm);
        padding-top: 80px;
    }

    .nav-container {
        padding: 0 var(--space-sm);
    }

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

    .article-content h2 {
        font-size: 1.3rem;
    }

    .article-content h3 {
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    .nav-menu {
        gap: 0;
    }

    .nav-link {
        padding: 8px 12px;
        font-size: 0.85rem;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .page-header .title {
        font-size: 1.75rem;
    }

    .article-content p,
    .article-content li {
        font-size: 0.95rem;
    }
}

/* ================================================
   ANIMATIONS
   ================================================ */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.page-header {
    animation: fadeInUp 0.6s ease-out;
}

.main {
    animation: fadeInUp 0.6s ease-out 0.1s both;
}

.article-content {
    animation: fadeInUp 0.5s ease-out 0.2s both;
}

/* ================================================
   GUIDE ELEMENTS: formula, worked example, tables, sources
   ================================================ */
.article-content strong {
    color: var(--color-text);
    font-weight: 600;
}

.article-content .formula,
.article-content .example {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-left: 3px solid var(--color-accent);
    border-radius: var(--radius-md);
    padding: var(--space-sm) var(--space-md);
    margin-bottom: var(--space-md);
}

.article-content .formula p,
.article-content .example p,
.article-content .example ul {
    margin-bottom: var(--space-xs);
}

.article-content .formula p:last-child,
.article-content .example p:last-child,
.article-content .example ul:last-child {
    margin-bottom: 0;
}

.article-content .formula code {
    font-family: var(--font-body);
    font-size: 1rem;
    color: var(--color-text);
    font-weight: 600;
}

.article-content .label {
    display: block;
    font-family: var(--font-display);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--color-accent);
    margin-bottom: 4px;
}

.table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    margin-bottom: var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
}

.article-content table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.92rem;
    line-height: 1.5;
}

.article-content th,
.article-content td {
    text-align: left;
    vertical-align: top;
    padding: 10px 14px;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-muted);
}

.article-content thead th {
    font-family: var(--font-display);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text);
    background: var(--color-surface);
}

.article-content tbody th {
    color: var(--color-text);
    font-weight: 600;
}

.article-content tbody tr:last-child th,
.article-content tbody tr:last-child td {
    border-bottom: none;
}

.article-content td.num {
    white-space: nowrap;
}

.table-wide {
    min-width: 640px;
}

.article-content .meta-line {
    font-size: 0.9rem;
}

.article-content .sources li {
    font-size: 0.92rem;
}

.article-content .disclosure {
    font-size: 0.95rem;
}

@media (max-width: 480px) {
    .article-content th,
    .article-content td {
        padding: 8px 10px;
    }

    .article-content .formula,
    .article-content .example {
        padding: var(--space-sm);
    }
}

/* Wide tables turn into stacked cards on phones */
@media (max-width: 600px) {
    .table-wrap-stack {
        overflow-x: visible;
    }

    .table-stack.table-wide {
        min-width: 0;
    }

    .table-stack thead {
        display: none;
    }

    .table-stack,
    .table-stack tbody,
    .table-stack tr,
    .table-stack th,
    .table-stack td {
        display: block;
        width: 100%;
    }

    .table-stack tr {
        padding: 12px 14px;
        border-bottom: 1px solid var(--color-border);
    }

    .table-stack tbody tr:last-child {
        border-bottom: none;
    }

    .table-stack th,
    .table-stack td {
        padding: 2px 0;
        border-bottom: none;
    }

    .table-stack tbody th:empty {
        display: none;
    }

    .table-stack tbody th {
        font-family: var(--font-display);
        margin-bottom: 4px;
    }

    .table-stack td::before {
        content: attr(data-label);
        display: block;
        font-size: 0.72rem;
        font-weight: 600;
        text-transform: uppercase;
        letter-spacing: 0.06em;
        color: var(--color-accent);
        margin-top: 6px;
    }

    .table-stack td.num {
        white-space: normal;
    }
}