/* ==========================================================================
   Ertunç Özbay — Personal Workshop, Project Lab & Technical Notebook
   Vibrant Luminous Engineering Studio + Daylight Theme Support
   Plain CSS • Accessible • Responsive • Reduced-Motion Ready
   ========================================================================== */

:root {
  /* Luminous Indigo-Slate Canvas (Brighter, Richer, Colorful) */
  --bg-primary: #111827;
  --bg-secondary: #182235;
  --bg-card: #1e293b;
  --bg-card-hover: #243248;
  --bg-code: #0f172a;
  --bg-header: rgba(17, 24, 39, 0.88);

  /* Crisp Borders & Hairlines */
  --border-subtle: #334155;
  --border-strong: #475569;
  --border-accent: #f59e0b;

  /* High-Contrast Typography */
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;

  /* Multi-Color Engineering Accents */
  --accent-amber: #f59e0b;
  --accent-amber-soft: rgba(245, 158, 11, 0.16);
  --accent-teal: #06b6d4;
  --accent-teal-soft: rgba(6, 182, 212, 0.16);
  --accent-emerald: #10b981;
  --accent-emerald-soft: rgba(16, 185, 129, 0.16);
  --accent-magenta: #ec4899;
  --accent-magenta-soft: rgba(236, 72, 153, 0.16);
  --accent-violet: #8b5cf6;
  --accent-violet-soft: rgba(139, 92, 246, 0.16);
  --accent-coral: #f43f5e;
  --accent-coral-soft: rgba(244, 63, 94, 0.16);
  --accent-blue: #38bdf8;
  --accent-youtube: #ff0033;

  /* Gradients */
  --grad-hero: linear-gradient(135deg, rgba(30, 41, 59, 0.96) 0%, rgba(24, 34, 53, 0.96) 55%, rgba(36, 28, 62, 0.92) 100%);
  --grad-brand: linear-gradient(135deg, #f59e0b 0%, #ec4899 55%, #06b6d4 100%);
  --grad-amber: linear-gradient(90deg, #f59e0b, #f97316);
  --grad-synth: linear-gradient(90deg, #ec4899, #8b5cf6, #06b6d4);
  --grad-emerald: linear-gradient(90deg, #10b981, #06b6d4);
  --grad-coral: linear-gradient(90deg, #f43f5e, #fb923c);

  /* Typography & Rhythm */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --max-width: 1100px;
  --max-reading-width: 74ch;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 18px;
  --shadow-panel: 0 12px 32px rgba(2, 6, 23, 0.42);
  --shadow-card: 0 8px 24px rgba(2, 6, 23, 0.28);
}

/* Optional Sunlit Studio Light Mode */
[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #f1f5f9;
  --bg-card: #ffffff;
  --bg-card-hover: #f8fafc;
  --bg-code: #0f172a;
  --bg-header: rgba(255, 255, 255, 0.90);

  --border-subtle: #e2e8f0;
  --border-strong: #cbd5e1;
  --border-accent: #d97706;

  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;

  --accent-amber: #d97706;
  --accent-amber-soft: rgba(217, 119, 6, 0.12);
  --accent-teal: #0891b2;
  --accent-teal-soft: rgba(8, 145, 178, 0.12);
  --accent-emerald: #059669;
  --accent-emerald-soft: rgba(5, 150, 105, 0.12);
  --accent-magenta: #db2777;
  --accent-magenta-soft: rgba(219, 39, 119, 0.12);
  --accent-violet: #7c3aed;
  --accent-violet-soft: rgba(124, 58, 237, 0.12);
  --accent-coral: #e11d48;
  --accent-coral-soft: rgba(225, 29, 72, 0.12);
  --accent-blue: #0284c7;

  --grad-hero: linear-gradient(135deg, #ffffff 0%, #f0f9ff 50%, #fdf4ff 100%);
  --shadow-panel: 0 12px 32px rgba(15, 23, 42, 0.08);
  --shadow-card: 0 6px 20px rgba(15, 23, 42, 0.06);
}

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

html {
  font-size: 100%;
  scroll-behavior: smooth;
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

body {
  margin: 0;
  font-family: var(--font-sans);
  line-height: 1.68;
  background-color: var(--bg-primary);
  background-image:
    radial-gradient(circle at 12% 10%, rgba(6, 182, 212, 0.14), transparent 34%),
    radial-gradient(circle at 88% 14%, rgba(236, 72, 153, 0.13), transparent 34%),
    radial-gradient(circle at 50% 85%, rgba(245, 158, 11, 0.10), transparent 40%),
    radial-gradient(rgba(148, 163, 184, 0.08) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 100% 100%, 28px 28px;
  background-attachment: fixed;
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Accessibility: Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  z-index: 1000;
  background: var(--grad-amber);
  color: #0f172a;
  padding: 0.65rem 1.1rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  text-decoration: none;
  box-shadow: var(--shadow-panel);
}

.skip-link:focus {
  top: 1rem;
  outline: 3px solid #ffffff;
  outline-offset: 2px;
}

/* Accessibility: Visible Keyboard Focus States */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
summary:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--accent-teal);
  outline-offset: 3px;
  border-radius: 4px;
}

/* Typography Hierarchy */
h1, h2, h3, h4 {
  color: var(--text-primary);
  line-height: 1.24;
  margin-top: 0;
  font-weight: 800;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(1.95rem, 3.6vw, 2.75rem);
  margin-bottom: 1rem;
}

.gradient-title {
  background: linear-gradient(90deg, var(--text-primary) 0%, #38bdf8 48%, #f59e0b 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  display: inline-block;
}

h2 {
  font-size: clamp(1.38rem, 2.5vw, 1.85rem);
  margin-bottom: 0.85rem;
}

h3 {
  font-size: 1.22rem;
  margin-bottom: 0.55rem;
}

p {
  margin-top: 0;
  margin-bottom: 1.15rem;
  color: var(--text-secondary);
}

ul, ol {
  margin-top: 0;
  margin-bottom: 1.15rem;
  padding-left: 1.35rem;
  color: var(--text-secondary);
}

li {
  margin-bottom: 0.45rem;
}

strong {
  color: var(--text-primary);
  font-weight: 650;
}

code, pre {
  font-family: var(--font-mono);
  font-size: 0.9em;
}

code {
  background-color: rgba(15, 23, 42, 0.75);
  color: #38bdf8;
  padding: 0.16rem 0.45rem;
  border-radius: 5px;
  border: 1px solid var(--border-subtle);
}

[data-theme="light"] code {
  background-color: #f1f5f9;
  color: #0369a1;
}

pre {
  background-color: var(--bg-code);
  color: #f8fafc;
  padding: 1.1rem 1.25rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  overflow-x: auto;
  line-height: 1.55;
}

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

a {
  color: var(--accent-teal);
  text-decoration: underline;
  text-underline-offset: 0.22em;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--accent-amber);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Layout Containers */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.35rem;
}

.reading-width {
  max-width: var(--max-reading-width);
}

main {
  flex: 1;
  padding: 2.5rem 0 4.5rem;
}

/* Header & Navigation */
.site-header {
  background-color: var(--bg-header);
  border-bottom: 1px solid var(--border-subtle);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(14px);
}

.site-header::before {
  content: "";
  display: block;
  height: 3px;
  width: 100%;
  background: linear-gradient(90deg, #06b6d4 0%, #8b5cf6 35%, #ec4899 68%, #f59e0b 100%);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 4.4rem;
  gap: 1rem;
}

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 800;
  font-size: 1.08rem;
}

.site-brand:hover {
  color: var(--accent-teal);
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  background: var(--grad-brand);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.88rem;
  font-weight: 800;
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(236, 72, 153, 0.3);
}

.brand-subtitle {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--accent-teal);
}

/* Mobile Navigation Button & Theme Button */
.nav-toggle,
.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background-color: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 0.45rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}

.nav-toggle {
  display: none;
}

.nav-toggle:hover,
.theme-toggle:hover {
  border-color: var(--accent-teal);
  color: var(--accent-teal);
  transform: translateY(-1px);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-list li {
  margin: 0;
}

.nav-link {
  display: inline-block;
  padding: 0.45rem 0.85rem;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  transition: all 0.15s ease;
}

.nav-link:hover {
  color: var(--text-primary);
  background-color: var(--bg-card);
  border-color: var(--border-subtle);
}

.nav-link[aria-current="page"] {
  color: #ffffff;
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.28), rgba(139, 92, 246, 0.28));
  border-color: rgba(6, 182, 212, 0.55);
}

[data-theme="light"] .nav-link[aria-current="page"] {
  color: #0f172a;
}

/* Workshop Hero / Intro Panel */
.workshop-hero {
  position: relative;
  background: var(--grad-hero);
  border: 1px solid var(--border-strong);
  border-left: 5px solid var(--accent-teal);
  border-radius: var(--radius-lg);
  padding: clamp(1.65rem, 3.8vw, 2.75rem);
  margin-bottom: 2.75rem;
  box-shadow: var(--shadow-panel);
  overflow: hidden;
}

.workshop-hero::after {
  content: "";
  position: absolute;
  top: -60px;
  right: -60px;
  width: 240px;
  height: 240px;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.18) 0%, rgba(236, 72, 153, 0.10) 50%, transparent 70%);
  pointer-events: none;
}

.workshop-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent-teal);
  background-color: var(--accent-teal-soft);
  border: 1px solid rgba(6, 182, 212, 0.45);
  padding: 0.28rem 0.75rem;
  border-radius: 999px;
  margin-bottom: 1rem;
}

.hero-lead {
  font-size: clamp(1.12rem, 2.1vw, 1.32rem);
  color: var(--text-primary);
  max-width: 66ch;
  margin-bottom: 1rem;
  font-weight: 500;
}

.hero-supporting-line {
  font-family: var(--font-mono);
  font-size: 0.92rem;
  color: var(--accent-amber);
  margin-top: 1.1rem;
  margin-bottom: 1.5rem;
  font-weight: 600;
}

/* Stats / Quick Highlights Bar */
.stats-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.9rem;
  margin-top: 1.65rem;
  padding-top: 1.35rem;
  border-top: 1px solid var(--border-subtle);
}

.stat-pill {
  background-color: rgba(15, 23, 42, 0.45);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
}

[data-theme="light"] .stat-pill {
  background-color: rgba(255, 255, 255, 0.8);
}

.stat-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--accent-teal);
}

.stat-pill:nth-child(2) .stat-value { color: var(--accent-amber); }
.stat-pill:nth-child(3) .stat-value { color: var(--accent-magenta); }
.stat-pill:nth-child(4) .stat-value { color: var(--accent-emerald); }

.stat-label {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Buttons */
.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.62rem 1.15rem;
  font-size: 0.94rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.18s ease;
}

.btn-primary {
  background: linear-gradient(135deg, #f59e0b 0%, #f97316 100%);
  color: #0f172a;
  box-shadow: 0 4px 14px rgba(245, 158, 11, 0.3);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #fbbf24 0%, #fb923c 100%);
  color: #0f172a;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(245, 158, 11, 0.45);
}

.btn-cyan {
  background: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(6, 182, 212, 0.3);
}

.btn-cyan:hover {
  background: linear-gradient(135deg, #22d3ee 0%, #60a5fa 100%);
  color: #ffffff;
  transform: translateY(-1px);
}

.btn-youtube {
  background: linear-gradient(135deg, #ff0033 0%, #e11d48 100%);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(255, 0, 51, 0.28);
}

.btn-youtube:hover {
  background: linear-gradient(135deg, #ff1a47 0%, #f43f5e 100%);
  color: #ffffff;
  transform: translateY(-1px);
}

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

.btn-secondary:hover {
  background-color: var(--bg-card-hover);
  border-color: var(--accent-teal);
  color: var(--accent-teal);
  transform: translateY(-1px);
}

/* Section Headers & Grid Layouts */
.section-block {
  margin-bottom: 3.25rem;
}

.section-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 0.65rem;
  margin-bottom: 1.45rem;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-teal);
  display: block;
  margin-bottom: 0.25rem;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.35rem;
}

.card-grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(330px, 1fr));
  gap: 1.35rem;
}

/* Colorful Engineering Cards */
.card {
  position: relative;
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-top: 3px solid var(--accent-teal);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-card);
  transition: transform 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.card:hover {
  border-color: var(--border-strong);
  transform: translateY(-3px);
  box-shadow: var(--shadow-panel);
}

.card.card-amber { border-top-color: var(--accent-amber); }
.card.card-synth { border-top-color: var(--accent-magenta); }
.card.card-emerald { border-top-color: var(--accent-emerald); }
.card.card-coral { border-top-color: var(--accent-coral); }
.card.card-violet { border-top-color: var(--accent-violet); }

.card-top {
  margin-bottom: 1rem;
}

.card h3 a {
  color: var(--text-primary);
  text-decoration: none;
}

.card h3 a:hover {
  color: var(--accent-teal);
  text-decoration: underline;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.8rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* Badges & Colorful Tech Tags */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 700;
  padding: 0.22rem 0.6rem;
  border-radius: 999px;
  border: 1px solid transparent;
}

.badge-progress {
  background-color: var(--accent-amber-soft);
  color: var(--accent-amber);
  border-color: rgba(245, 158, 11, 0.45);
}

.badge-experimental {
  background-color: var(--accent-magenta-soft);
  color: var(--accent-magenta);
  border-color: rgba(236, 72, 153, 0.45);
}

.badge-active {
  background-color: var(--accent-emerald-soft);
  color: var(--accent-emerald);
  border-color: rgba(16, 185, 129, 0.45);
}

.badge-coral {
  background-color: var(--accent-coral-soft);
  color: var(--accent-coral);
  border-color: rgba(244, 63, 94, 0.45);
}

.badge-draft {
  background-color: var(--accent-teal-soft);
  color: var(--accent-teal);
  border-color: rgba(6, 182, 212, 0.45);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  list-style: none;
  padding: 0;
  margin: 0.75rem 0 1rem;
}

.tag-list li {
  margin: 0;
}

.tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  padding: 0.2rem 0.6rem;
  border-radius: 6px;
}

.tag.tag-c { color: #38bdf8; border-color: rgba(56, 189, 248, 0.35); background: rgba(56, 189, 248, 0.1); }
.tag.tag-esp { color: #f59e0b; border-color: rgba(245, 158, 11, 0.35); background: rgba(245, 158, 11, 0.1); }
.tag.tag-rust { color: #fb7185; border-color: rgba(251, 113, 133, 0.35); background: rgba(251, 113, 133, 0.1); }
.tag.tag-python { color: #a78bfa; border-color: rgba(167, 139, 250, 0.35); background: rgba(167, 139, 250, 0.1); }
.tag.tag-hw { color: #34d399; border-color: rgba(52, 211, 153, 0.35); background: rgba(52, 211, 153, 0.1); }
.tag.tag-synth { color: #f472b6; border-color: rgba(244, 114, 182, 0.35); background: rgba(244, 114, 182, 0.1); }

/* Project Card Learning / Next Step Callouts */
.project-notes {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-left: 3px solid var(--accent-violet);
  border-radius: var(--radius-sm);
  padding: 0.9rem 1.05rem;
  margin: 0.85rem 0 1.1rem;
  font-size: 0.92rem;
}

.project-notes p {
  margin-bottom: 0.45rem;
}

.project-notes p:last-child {
  margin-bottom: 0;
}

.card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  padding-top: 0.95rem;
  border-top: 1px solid var(--border-subtle);
}

/* ==========================================================================
   YouTube Proof-of-Concept (PoC) Video Placeholder Component
   ========================================================================== */
.poc-video-section {
  margin: 2rem 0 2.75rem;
}

.poc-video-card {
  position: relative;
  background: linear-gradient(135deg, rgba(15, 23, 42, 0.95) 0%, rgba(30, 27, 75, 0.92) 50%, rgba(49, 16, 47, 0.9) 100%);
  border: 1px solid rgba(244, 63, 94, 0.45);
  border-radius: var(--radius-lg);
  padding: clamp(1.35rem, 3vw, 2.2rem);
  box-shadow: 0 14px 36px rgba(244, 63, 94, 0.14);
  overflow: hidden;
}

.poc-video-screen {
  position: relative;
  aspect-ratio: 16 / 9;
  width: 100%;
  background:
    radial-gradient(circle at 50% 50%, rgba(255, 0, 51, 0.18), transparent 60%),
    repeating-linear-gradient(0deg, rgba(255, 255, 255, 0.02) 0px, rgba(255, 255, 255, 0.02) 1px, transparent 1px, transparent 24px),
    linear-gradient(180deg, #090d16 0%, #111827 100%);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 1.5rem;
  color: #f8fafc;
}

.poc-play-badge {
  width: 74px;
  height: 52px;
  background: linear-gradient(135deg, #ff0033 0%, #e11d48 100%);
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 0 8px rgba(255, 0, 51, 0.18), 0 10px 28px rgba(255, 0, 51, 0.45);
  margin-bottom: 1rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.poc-video-screen:hover .poc-play-badge {
  transform: scale(1.07);
  box-shadow: 0 0 0 12px rgba(255, 0, 51, 0.25), 0 14px 32px rgba(255, 0, 51, 0.6);
}

.poc-play-triangle {
  width: 0;
  height: 0;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-left: 18px solid #ffffff;
  margin-left: 4px;
}

.poc-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #fda4af;
  background: rgba(244, 63, 94, 0.2);
  border: 1px solid rgba(244, 63, 94, 0.45);
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  margin-bottom: 0.6rem;
}

.poc-video-title {
  font-size: clamp(1.15rem, 2.2vw, 1.45rem);
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 0.4rem;
}

.poc-video-desc {
  color: #cbd5e1;
  max-width: 56ch;
  font-size: 0.94rem;
  margin-bottom: 0;
}

/* Callout / Philosophy Panels */
.callout-box {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-strong);
  border-left: 4px solid var(--accent-teal);
  border-radius: var(--radius-md);
  padding: 1.4rem 1.55rem;
  margin: 1.5rem 0;
}

.callout-box.amber {
  border-left-color: var(--accent-amber);
}

.callout-box.magenta {
  border-left-color: var(--accent-magenta);
}

.callout-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-teal);
  margin-bottom: 0.5rem;
  display: block;
}

.callout-box.amber .callout-title {
  color: var(--accent-amber);
}

.callout-box.magenta .callout-title {
  color: var(--accent-magenta);
}

/* Figure & Schematic Frames + Zoomable Images */
.schematic-frame {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.1rem;
  margin: 1.6rem 0;
}

.schematic-caption {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 0.75rem;
  text-align: center;
}

.zoomable-img {
  cursor: zoom-in;
  transition: transform 0.2s ease;
}

.zoomable-img:hover {
  transform: scale(1.015);
}

/* Lightbox Overlay */
.lightbox-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(2, 6, 23, 0.92);
  backdrop-filter: blur(8px);
  z-index: 2000;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

.lightbox-backdrop[hidden] {
  display: none;
}

.lightbox-Backdrop-img {
  max-width: 92vw;
  max-height: 82vh;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-strong);
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.65);
  background: #ffffff;
}

.lightbox-caption {
  margin-top: 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: #f8fafc;
  text-align: center;
}

.lightbox-close {
  position: absolute;
  top: 1.25rem;
  right: 1.5rem;
  background: var(--bg-card);
  color: #ffffff;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 0.45rem 0.9rem;
  font-family: var(--font-mono);
  cursor: pointer;
}

/* Breadcrumb / Back Navigation */
.breadcrumb {
  margin-bottom: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.breadcrumb a {
  color: var(--accent-teal);
  text-decoration: none;
}

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

/* Filter Toolbar for Blog */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.filter-btn {
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
  padding: 0.45rem 0.9rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
}

.filter-btn:hover {
  border-color: var(--accent-teal);
  color: var(--text-primary);
}

.filter-btn[aria-pressed="true"] {
  background-color: var(--accent-teal-soft);
  color: var(--accent-teal);
  border-color: var(--accent-teal);
  font-weight: 700;
}

/* Spec / Component Table */
.spec-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0 1.5rem;
  font-size: 0.95rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.spec-table th,
.spec-table td {
  text-align: left;
  padding: 0.8rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.spec-table th {
  background-color: var(--bg-card);
  color: var(--accent-teal);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.spec-table td {
  color: var(--text-secondary);
}

/* Footer */
.site-footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  padding: 2.25rem 0;
  margin-top: auto;
  font-size: 0.92rem;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.1rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-links li {
  margin: 0;
}

/* Responsive Mobile Navigation */
@media (max-width: 780px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    width: 100%;
    display: none;
  }

  .site-nav.is-open {
    display: block;
    padding: 0.75rem 0 1rem;
    border-top: 1px solid var(--border-subtle);
  }

  .header-inner {
    flex-wrap: wrap;
    padding-top: 0.6rem;
    padding-bottom: 0.6rem;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
  }

  .nav-link {
    display: block;
    padding: 0.65rem 0.85rem;
  }
}

/* Accessibility: Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}