/* ============================================
   RPiServer.com - Main Stylesheet
   Design: Technical Editorial / Dark Homelab Aesthetic
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&family=Sora:wght@300;400;500;600;700;800&family=Lora:ital,wght@0,400;0,500;1,400&display=swap');

:root {
  --bg-primary: #0a0e14;
  --bg-secondary: #0f1520;
  --bg-card: #131c2b;
  --bg-card-hover: #182233;
  --border: #1e2d42;
  --border-light: #243548;

  --text-primary: #e8edf5;
  --text-secondary: #8fa3bd;
  --text-muted: #556b85;
  --text-code: #7dd3fc;

  --accent-red: #e5383b;
  --accent-red-dim: #c0222580;
  --accent-green: #22c55e;
  --accent-blue: #3b82f6;
  --accent-amber: #f59e0b;
  --accent-purple: #a855f7;

  --rpi-red: #c51a4a;
  --rpi-red-bright: #e8204f;
  --rpi-red-glow: rgba(197, 26, 74, 0.15);

  --font-display: 'Sora', sans-serif;
  --font-body: 'Lora', Georgia, serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 14px;
  --radius-xl: 20px;

  --shadow-card: 0 4px 24px rgba(0,0,0,0.4);
  --shadow-glow: 0 0 40px rgba(197, 26, 74, 0.12);
  --shadow-glow-blue: 0 0 40px rgba(59,130,246,0.08);

  --nav-height: 68px;
  --content-max: 1200px;
  --article-max: 780px;
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* ─── SCROLLBAR ─── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--border-light); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--rpi-red); }

/* ─── TYPOGRAPHY ─── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  color: var(--text-primary);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 4vw, 3.2rem); font-weight: 800; }
h2 { font-size: clamp(1.5rem, 3vw, 2.2rem); font-weight: 700; }
h3 { font-size: clamp(1.2rem, 2.5vw, 1.6rem); font-weight: 600; }
h4 { font-size: 1.1rem; font-weight: 600; }

p { color: var(--text-secondary); font-size: 1.05rem; }

a { color: var(--rpi-red-bright); text-decoration: none; transition: color 0.2s; }
a:hover { color: #ff4d73; }

code, kbd {
  font-family: var(--font-mono);
  font-size: 0.875em;
  color: var(--text-code);
  background: rgba(59,130,246,0.1);
  border: 1px solid rgba(59,130,246,0.2);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

pre {
  font-family: var(--font-mono);
  background: #060b12;
  border: 1px solid var(--border);
  border-left: 3px solid var(--rpi-red);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  font-size: 0.875rem;
  color: #a8d8ea;
  line-height: 1.7;
  margin: 1.5rem 0;
}

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

strong { color: var(--text-primary); font-weight: 600; }
em { color: var(--accent-amber); }
img { max-width: 100%; height: auto; display: block; }

/* ─── LAYOUT ─── */
.container { max-width: var(--content-max); margin: 0 auto; padding: 0 24px; }
.container-narrow { max-width: 860px; margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-sm { padding: 48px 0; }

/* ─── NAVIGATION ─── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background: rgba(10, 14, 20, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.nav-logo-icon {
  width: 32px;
  height: 32px;
  background: var(--rpi-red);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: white;
  letter-spacing: -0.5px;
  flex-shrink: 0;
}

.nav-logo-text {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

/* .nav-logo-text span - inherits parent color, wordmark is uniform */
.nav-logo-text span {
  color: inherit;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}

.nav-links a {
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: all 0.2s;
  text-decoration: none;
}

.nav-links a:hover {
  color: var(--text-primary);
  background: var(--bg-card);
}

.nav-cta {
  background: var(--rpi-red) !important;
  color: white !important;
  padding: 7px 16px !important;
  border-radius: var(--radius-sm) !important;
}

.nav-cta:hover { background: var(--rpi-red-bright) !important; }

.nav-search {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  cursor: pointer;
  transition: border-color 0.2s;
}

.nav-search:hover { border-color: var(--border-light); }

.nav-search input {
  background: none;
  border: none;
  outline: none;
  color: var(--text-secondary);
  font-family: var(--font-display);
  font-size: 0.8rem;
  width: 140px;
}

.nav-search input::placeholder { color: var(--text-muted); }

.nav-right { display: flex; align-items: center; gap: 12px; }

.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 4px; }
.hamburger span { width: 22px; height: 2px; background: var(--text-secondary); border-radius: 2px; transition: all 0.3s; }

/* ─── HERO ─── */
.hero {
  position: relative;
  padding: 100px 0 80px;
  overflow: hidden;
}

.hero-grid-bg {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(197,26,74,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(197,26,74,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse at 50% 0%, black 30%, transparent 80%);
  -webkit-mask-image: radial-gradient(ellipse at 50% 0%, black 30%, transparent 80%);
}

.hero-glow {
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 400px;
  background: radial-gradient(ellipse, rgba(197,26,74,0.12) 0%, transparent 70%);
  pointer-events: none;
}

.hero-content { position: relative; z-index: 1; }

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--rpi-red-glow);
  border: 1px solid var(--accent-red-dim);
  color: var(--rpi-red-bright);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  padding: 5px 12px;
  border-radius: 100px;
  margin-bottom: 24px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.hero-eyebrow::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--rpi-red-bright);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.8); }
}

.hero-title { margin-bottom: 20px; }
.hero-title .highlight { color: var(--rpi-red-bright); position: relative; }

.hero-desc {
  font-size: 1.15rem;
  max-width: 620px;
  margin-bottom: 36px;
  line-height: 1.8;
}

.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 60px; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  letter-spacing: -0.01em;
}

.btn-primary {
  background: var(--rpi-red);
  color: white;
  box-shadow: 0 0 20px rgba(197,26,74,0.3);
}

.btn-primary:hover {
  background: var(--rpi-red-bright);
  color: white;
  box-shadow: 0 0 30px rgba(197,26,74,0.4);
  transform: translateY(-1px);
}

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

.btn-secondary:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border-color: var(--text-muted);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  padding: 10px 16px;
}

.btn-ghost:hover { color: var(--text-primary); background: var(--bg-card); }

.hero-stats {
  display: flex;
  gap: 40px;
  flex-wrap: wrap;
}

.hero-stat {}
.hero-stat-num {
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

.hero-stat-num span { color: var(--rpi-red-bright); }
.hero-stat-label { font-size: 0.8rem; color: var(--text-muted); font-family: var(--font-display); }

/* ─── TERMINAL WIDGET ─── */
.terminal {
  background: #060b12;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  font-family: var(--font-mono);
}

.terminal-bar {
  background: #0d141f;
  padding: 10px 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--border);
}

.terminal-dot { width: 10px; height: 10px; border-radius: 50%; }
.terminal-dot.red { background: #ff5f57; }
.terminal-dot.yellow { background: #febc2e; }
.terminal-dot.green { background: #28c840; }
.terminal-title {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-left: 8px;
  letter-spacing: 0.02em;
}

.terminal-body { padding: 20px 24px; font-size: 0.8rem; line-height: 2; color: #6b8caa; }
.terminal-body .prompt { color: var(--rpi-red-bright); }
.terminal-body .cmd { color: #a8d8ea; }
.terminal-body .comment { color: #3a5068; }
.terminal-body .output { color: #4a7c59; }
.terminal-body .success { color: var(--accent-green); }

.cursor {
  display: inline-block;
  width: 8px;
  height: 14px;
  background: var(--rpi-red-bright);
  vertical-align: middle;
  animation: blink 1s step-end infinite;
  margin-left: 2px;
}

@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0; } }

/* ─── SECTION HEADERS ─── */
.section-header { margin-bottom: 48px; }
.section-header.centered { text-align: center; }
.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--rpi-red-bright);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 12px;
}

.section-tag::before {
  content: '//';
  color: var(--text-muted);
}

.section-title { margin-bottom: 12px; }
.section-desc { color: var(--text-secondary); font-size: 1.05rem; max-width: 580px; }
.section-header.centered .section-desc { margin: 0 auto; }

/* ─── CARDS ─── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all 0.25s;
  text-decoration: none;
  display: block;
}

.card:hover {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.card-thumb {
  aspect-ratio: 16/9;
  background: var(--bg-secondary);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.card-thumb-icon {
  font-size: 3rem;
  opacity: 0.15;
}

.card-thumb-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: flex-end;
  padding: 16px;
}

.card-category-pill {
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  border-radius: 100px;
  border: 1px solid;
}

.pill-red { background: rgba(197,26,74,0.15); border-color: rgba(197,26,74,0.4); color: #ff4d73; }
.pill-blue { background: rgba(59,130,246,0.1); border-color: rgba(59,130,246,0.3); color: #60a5fa; }
.pill-green { background: rgba(34,197,94,0.1); border-color: rgba(34,197,94,0.3); color: #4ade80; }
.pill-amber { background: rgba(245,158,11,0.1); border-color: rgba(245,158,11,0.3); color: #fbbf24; }
.pill-purple { background: rgba(168,85,247,0.1); border-color: rgba(168,85,247,0.3); color: #c084fc; }

.card-body { padding: 20px 22px 22px; }
.card-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
  margin-bottom: 8px;
  letter-spacing: -0.02em;
}

.card:hover .card-title { color: white; }

.card-excerpt {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 16px;
  font-family: var(--font-display);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-display);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.card-meta-divider { color: var(--border-light); }
.card-read-time { color: var(--rpi-red-bright); }

/* ─── FEATURED CARD ─── */
.featured-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  display: grid;
  grid-template-columns: 1fr 1fr;
  overflow: hidden;
  transition: all 0.25s;
  text-decoration: none;
}

.featured-card:hover {
  border-color: var(--border-light);
  box-shadow: var(--shadow-glow), var(--shadow-card);
}

.featured-card-body { padding: 40px; display: flex; flex-direction: column; justify-content: center; }
.featured-card-tag { margin-bottom: 16px; }
.featured-card-title {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 2.5vw, 1.7rem);
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.3;
  margin-bottom: 14px;
  letter-spacing: -0.03em;
}

.featured-card:hover .featured-card-title { color: white; }

.featured-card-excerpt {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 24px;
}

.featured-card-footer {
  display: flex;
  align-items: center;
  gap: 16px;
  font-family: var(--font-display);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.featured-card-visual {
  background: linear-gradient(135deg, #0d1821 0%, #1a2a3a 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px;
  position: relative;
  overflow: hidden;
}

/* ─── GRID LAYOUTS ─── */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }

/* ─── CATEGORY PILLS NAV ─── */
.category-nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.cat-btn {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 500;
  padding: 7px 16px;
  border-radius: 100px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
  display: inline-block;
}

.cat-btn:hover, .cat-btn.active {
  background: var(--rpi-red);
  border-color: var(--rpi-red);
  color: white;
}

/* ─── TOPIC BOXES ─── */
.topic-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-decoration: none;
  display: block;
  transition: all 0.25s;
  position: relative;
  overflow: hidden;
}

.topic-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--topic-color, var(--rpi-red));
  transform: scaleX(0);
  transition: transform 0.3s;
}

.topic-card:hover::before { transform: scaleX(1); }
.topic-card:hover {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
}

.topic-icon { font-size: 2rem; margin-bottom: 14px; }
.topic-name {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
  letter-spacing: -0.02em;
}

.topic-count {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ─── ARTICLE PAGE ─── */
.article-header { padding: 60px 0 40px; border-bottom: 1px solid var(--border); margin-bottom: 48px; }
.article-meta-top { display: flex; align-items: center; gap: 12px; margin-bottom: 20px; flex-wrap: wrap; }
.article-title { margin-bottom: 20px; }
.article-desc { font-size: 1.15rem; line-height: 1.75; margin-bottom: 28px; }

.author-row {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.author-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--rpi-red), #8b1a3a);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1rem;
  color: white;
  flex-shrink: 0;
}

.author-info {}
.author-name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary);
}

.author-cred {
  font-family: var(--font-display);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.article-actions { display: flex; gap: 8px; margin-left: auto; }

/* Article Content */
.article-content {}
.article-content h2 { margin: 2.5rem 0 1rem; padding-bottom: 8px; border-bottom: 1px solid var(--border); }
.article-content h3 { margin: 2rem 0 0.75rem; }
.article-content h4 { margin: 1.5rem 0 0.5rem; }
.article-content p { margin-bottom: 1.25rem; }
.article-content ul, .article-content ol { padding-left: 1.5rem; margin-bottom: 1.25rem; color: var(--text-secondary); }
.article-content li { margin-bottom: 0.5rem; }
.article-content a { border-bottom: 1px solid rgba(232,32,79,0.3); }
.article-content a:hover { border-bottom-color: var(--rpi-red-bright); }

/* Table of Contents */
.toc {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid var(--rpi-red);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 0 0 2rem;
}

.toc-title {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--rpi-red-bright);
  margin-bottom: 12px;
}

.toc ol { padding-left: 1.25rem; }
.toc li { margin-bottom: 6px; }
.toc a {
  font-family: var(--font-display);
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  border: none !important;
  transition: color 0.2s;
}
.toc a:hover { color: var(--text-primary); }

/* Callout / Info boxes */
.callout {
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin: 1.5rem 0;
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.callout-info { background: rgba(59,130,246,0.08); border: 1px solid rgba(59,130,246,0.2); }
.callout-warn { background: rgba(245,158,11,0.08); border: 1px solid rgba(245,158,11,0.2); }
.callout-success { background: rgba(34,197,94,0.08); border: 1px solid rgba(34,197,94,0.2); }
.callout-danger { background: rgba(197,26,74,0.08); border: 1px solid rgba(197,26,74,0.25); }

.callout-icon { font-size: 1.1rem; flex-shrink: 0; margin-top: 2px; }
.callout-body {}
.callout-body strong { display: block; font-family: var(--font-display); font-size: 0.875rem; margin-bottom: 4px; }
.callout-body p { font-size: 0.9rem; margin: 0; }
.callout-info .callout-body strong { color: #60a5fa; }
.callout-warn .callout-body strong { color: #fbbf24; }
.callout-success .callout-body strong { color: #4ade80; }
.callout-danger .callout-body strong { color: #ff4d73; }

/* ─── PRODUCT RECOMMENDATION ─── */
.product-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  display: flex;
  gap: 16px;
  align-items: flex-start;
  margin: 1.5rem 0;
}

.product-badge {
  background: var(--rpi-red-glow);
  border: 1px solid var(--accent-red-dim);
  color: var(--rpi-red-bright);
  font-family: var(--font-mono);
  font-size: 0.65rem;
  padding: 2px 8px;
  border-radius: 3px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  white-space: nowrap;
}

.product-info {}
.product-name {
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.product-desc { font-size: 0.85rem; color: var(--text-muted); margin-bottom: 12px; font-family: var(--font-display); }
.product-price {
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--accent-green);
  margin-bottom: 10px;
}

/* ─── NEWSLETTER ─── */
.newsletter-section {
  background: linear-gradient(135deg, var(--bg-card) 0%, #162030 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 60px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.newsletter-section::before {
  content: '';
  position: absolute;
  top: -60px;
  left: 50%;
  transform: translateX(-50%);
  width: 300px;
  height: 200px;
  background: radial-gradient(ellipse, rgba(197,26,74,0.1) 0%, transparent 70%);
}

.newsletter-form {
  display: flex;
  gap: 10px;
  max-width: 440px;
  margin: 24px auto 0;
}

.newsletter-input {
  flex: 1;
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  color: var(--text-primary);
  font-family: var(--font-display);
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.2s;
}

.newsletter-input:focus { border-color: var(--rpi-red); }
.newsletter-input::placeholder { color: var(--text-muted); }

/* ─── SIDEBAR ─── */
.sidebar-widget {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  margin-bottom: 20px;
}

.sidebar-widget-title {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--rpi-red-bright);
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.sidebar-list { list-style: none; }
.sidebar-list li { border-bottom: 1px solid var(--border); }
.sidebar-list li:last-child { border-bottom: none; }
.sidebar-list a {
  display: block;
  padding: 10px 0;
  font-family: var(--font-display);
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

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

/* ─── BREADCRUMB ─── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 0.8rem;
  color: var(--text-muted);
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 0;
  flex-wrap: wrap;
}

.breadcrumb a { color: var(--text-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--rpi-red-bright); }
.breadcrumb .sep { color: var(--border-light); }
.breadcrumb .current { color: var(--text-secondary); }

/* ─── FOOTER ─── */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 60px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand-desc {
  font-family: var(--font-display);
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-top: 12px;
  max-width: 280px;
}

.footer-col-title {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.footer-links { list-style: none; }
.footer-links li { margin-bottom: 10px; }
.footer-links a {
  font-family: var(--font-display);
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.2s;
}
.footer-links a:hover { color: var(--text-primary); }

.footer-bottom {
  border-top: 1px solid var(--border);
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-legal {
  font-family: var(--font-display);
  font-size: 0.775rem;
  color: var(--text-muted);
}

.footer-legal a { color: var(--text-muted); }
.footer-legal a:hover { color: var(--rpi-red-bright); }

.footer-disclaimer {
  font-family: var(--font-display);
  font-size: 0.7rem;
  color: var(--text-muted);
  text-align: center;
  padding: 12px 24px;
  border-top: 1px solid var(--border);
  line-height: 1.6;
}

/* ─── TAGS ─── */
.tag-cloud { display: flex; gap: 8px; flex-wrap: wrap; }
.tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  background: var(--bg-primary);
  border: 1px solid var(--border);
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: all 0.2s;
}

.tag:hover {
  color: var(--rpi-red-bright);
  border-color: var(--rpi-red);
  background: var(--rpi-red-glow);
}

/* ─── DIFFICULTY BADGE ─── */
.difficulty {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
}

.diff-beginner { background: rgba(34,197,94,0.1); color: #4ade80; border: 1px solid rgba(34,197,94,0.25); }
.diff-intermediate { background: rgba(245,158,11,0.1); color: #fbbf24; border: 1px solid rgba(245,158,11,0.25); }
.diff-advanced { background: rgba(197,26,74,0.1); color: #ff4d73; border: 1px solid rgba(197,26,74,0.25); }

/* ─── SEARCH BAR ─── */
.search-bar-full {
  display: flex;
  align-items: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 14px 20px;
  gap: 12px;
  transition: border-color 0.2s;
}

.search-bar-full:focus-within { border-color: var(--rpi-red); }
.search-bar-full input {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-family: var(--font-display);
  font-size: 1rem;
}

.search-bar-full input::placeholder { color: var(--text-muted); }

/* ─── AD SLOTS (reserved for future use) ─── */


/* ─── PAGINATION ─── */
.pagination {
  display: flex;
  gap: 6px;
  justify-content: center;
  margin-top: 48px;
  flex-wrap: wrap;
}

.page-btn {
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: var(--font-display);
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: all 0.2s;
  cursor: pointer;
}

.page-btn:hover, .page-btn.active {
  background: var(--rpi-red);
  border-color: var(--rpi-red);
  color: white;
}

/* ─── MISC ─── */
.divider { height: 1px; background: var(--border); margin: 40px 0; }
.text-red { color: var(--rpi-red-bright); }
.text-muted { color: var(--text-muted); }
.text-mono { font-family: var(--font-mono); }
.mt-auto { margin-top: auto; }

.icon-sm { width: 16px; height: 16px; }
.icon-md { width: 20px; height: 20px; }

/* ─── RESPONSIVE ─── */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .featured-card { grid-template-columns: 1fr; }
  .featured-card-visual { min-height: 200px; }
}

@media (max-width: 768px) {
  :root { --nav-height: 60px; }
  .nav-links { display: none; }
  .nav-search { display: none; }
  .hamburger { display: flex; }
  .grid-3 { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
  .grid-4 { grid-template-columns: 1fr; }
  .section { padding: 48px 0; }
  .hero { padding: 60px 0 48px; }
  .newsletter-section { padding: 36px 24px; }
  .newsletter-form { flex-direction: column; }
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .hero-stats { gap: 24px; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  h1 { font-size: 1.75rem; }
  .btn { padding: 10px 18px; font-size: 0.85rem; }
}

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

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.animate-fade-up { animation: fadeInUp 0.5s ease forwards; }
.animate-fade { animation: fadeIn 0.4s ease forwards; }

/* Staggered children */
.stagger > * {
  opacity: 0;
  animation: fadeInUp 0.5s ease forwards;
}

.stagger > *:nth-child(1) { animation-delay: 0.05s; }
.stagger > *:nth-child(2) { animation-delay: 0.1s; }
.stagger > *:nth-child(3) { animation-delay: 0.15s; }
.stagger > *:nth-child(4) { animation-delay: 0.2s; }
.stagger > *:nth-child(5) { animation-delay: 0.25s; }
.stagger > *:nth-child(6) { animation-delay: 0.3s; }

/* ─── MOBILE NAV ─── */
.mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  top: var(--nav-height);
  background: rgba(10,14,20,0.98);
  backdrop-filter: blur(12px);
  z-index: 99;
  padding: 24px;
  flex-direction: column;
  gap: 8px;
  border-top: 1px solid var(--border);
}

.mobile-nav.open { display: flex; }
.mobile-nav a {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
  text-decoration: none;
}

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

/* ─── TOPIC ICON TEXT LABELS (emoji replacement) ─── */
.ti-text {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--rpi-red-bright);
  background: var(--rpi-red-glow);
  border: 1px solid var(--accent-red-dim);
  padding: 4px 8px;
  border-radius: var(--radius-sm);
}

.topic-icon .ti-text {
  font-size: 0.75rem;
  padding: 6px 10px;
}

.card-thumb-icon.ti-text {
  font-size: 1.1rem;
  opacity: 0.6;
  background: none;
  border: none;
  color: var(--text-muted);
  padding: 0;
  letter-spacing: 0.1em;
}

.ti-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--accent-amber);
  background: rgba(245,158,11,0.1);
  border: 1px solid rgba(245,158,11,0.25);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  letter-spacing: 0.04em;
}