/* ============================================
   WALEED ALBADAWI — Tech Leader Portfolio
   Dark-first, engineering-grade design system
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
  --color-primary: #0a0a0f;
  --color-secondary: #12121a;
  --color-surface: #16161f;
  --color-surface-elevated: #1c1c28;
  --color-accent: #00d4aa;
  --color-accent-dim: #00a88a;
  --color-accent-glow: rgba(0, 212, 170, 0.15);
  --color-accent-border: rgba(0, 212, 170, 0.25);
  --color-blue: #4a9eff;
  --color-purple: #a78bfa;
  --color-text: #e4e4e7;
  --color-text-secondary: #a1a1aa;
  --color-text-muted: #71717a;
  --color-bg: #0a0a0f;
  --color-bg-alt: #0f0f16;
  --color-bg-dark: #060609;
  --color-border: rgba(255, 255, 255, 0.08);
  --color-border-light: rgba(255, 255, 255, 0.05);

  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', 'Cascadia Code', monospace;

  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 3rem;
  --space-xl: 5rem;
  --space-2xl: 8rem;

  --max-width: 1200px;
  --max-width-narrow: 800px;
  --max-width-wide: 1400px;

  --transition: 0.2s ease;
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(0, 212, 170, 0.1);

  --radius: 6px;
  --radius-lg: 12px;
}

/* --- Reset & Base --- */
*, *::before, *::after {
  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-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-weight: 400;
}

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

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}

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

::selection {
  background: var(--color-accent);
  color: var(--color-primary);
}

/* --- Typography --- */
h1, h2, h3, h4, h5 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text);
  letter-spacing: -0.03em;
}

h1 { font-size: clamp(2.2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.5rem); }
h3 { font-size: clamp(1.3rem, 2.5vw, 1.75rem); }
h4 { font-size: 1.125rem; }

p {
  margin-bottom: 1.25rem;
  font-size: 1rem;
  color: var(--color-text-secondary);
}

.lead {
  font-size: clamp(1.0625rem, 1.8vw, 1.2rem);
  color: var(--color-text-secondary);
  line-height: 1.8;
  font-weight: 400;
}

.overline {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-accent);
  display: inline-block;
  margin-bottom: 0.75rem;
  padding: 0.25rem 0.75rem;
  background: var(--color-accent-glow);
  border: 1px solid var(--color-accent-border);
  border-radius: 100px;
}

.section-subtitle {
  font-size: 1.0625rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  line-height: 1.7;
}

/* --- Layout --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
}

.container--narrow {
  max-width: var(--max-width-narrow);
}

.container--wide {
  max-width: var(--max-width-wide);
}

section {
  padding: var(--space-xl) 0;
  position: relative;
}

.section--alt {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.section--dark {
  background: var(--color-bg-dark);
  color: #fff;
  border-top: 1px solid var(--color-border);
}

.section--dark h2,
.section--dark h3,
.section--dark h4 {
  color: #fff;
}

.section--dark .overline {
  color: var(--color-accent);
}

.section--dark .section-subtitle,
.section--dark .lead,
.section--dark p {
  color: var(--color-text-secondary);
}

/* --- Grid --- */
.grid {
  display: grid;
  gap: 1.25rem;
}

.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 1024px) {
  .grid--3, .grid--4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; }
}

/* --- Header / Navigation --- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--color-border);
}

.site-header.scrolled {
  box-shadow: var(--shadow-md);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 2rem;
}

.site-logo {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
  letter-spacing: -0.01em;
}

.site-logo:hover {
  color: var(--color-text);
}

.site-logo span {
  color: var(--color-accent);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.site-nav a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.02em;
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius);
  transition: all var(--transition);
}

.site-nav a:hover {
  color: var(--color-text);
  background: var(--color-surface);
}

.site-nav a.active {
  color: var(--color-accent);
  background: var(--color-accent-glow);
}

/* Mobile menu */
.menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  padding: 0.5rem;
  color: var(--color-text);
}

.menu-toggle svg {
  width: 20px;
  height: 20px;
}

@media (max-width: 768px) {
  .menu-toggle {
    display: flex !important;
    align-items: center;
    justify-content: center;
    z-index: 1001;
    width: 44px;
    height: 44px;
    min-width: 44px;
    min-height: 44px;
    padding: 10px;
  }

  .site-nav {
    display: none !important;
    position: fixed !important;
    top: 64px !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    width: 100% !important;
    height: calc(100vh - 64px) !important;
    z-index: 999 !important;
    background: #0a0a0f !important;
    flex-direction: column !important;
    justify-content: flex-start !important;
    align-items: stretch !important;
    padding: 2rem !important;
    gap: 0.5rem !important;
    overflow-y: auto !important;
  }

  .site-nav.open {
    display: flex !important;
  }

  .site-nav a {
    font-size: 1.125rem;
    padding: 0.875rem 1rem;
    width: 100%;
    display: block;
  }
}

/* --- Hero --- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 64px;
  position: relative;
  overflow: hidden;
  background: var(--color-bg);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 60%;
  height: 100%;
  background: radial-gradient(ellipse at center, var(--color-accent-glow) 0%, transparent 70%);
  z-index: 0;
  opacity: 0.5;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-accent-border), transparent);
}

.hero__content {
  max-width: 720px;
  position: relative;
  z-index: 1;
}

.hero__greeting {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 1.5rem;
  display: block;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  margin-bottom: 1.5rem;
  line-height: 1.05;
  letter-spacing: -0.04em;
  background: linear-gradient(135deg, var(--color-text) 0%, var(--color-text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero h1 .accent {
  -webkit-text-fill-color: var(--color-accent);
}

.hero .lead {
  margin-bottom: 1.5rem;
  max-width: 580px;
}

.hero__actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.hero__scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  animation: float 3s ease-in-out infinite;
  z-index: 1;
}

@keyframes float {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(-6px); }
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}

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

.btn--primary:hover {
  background: #fff;
  color: var(--color-primary);
  box-shadow: var(--shadow-glow);
}

.btn--outline {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn--outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-glow);
}

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

.btn--accent:hover {
  background: #fff;
  color: var(--color-primary);
}

.btn--ghost {
  background: transparent;
  color: var(--color-accent);
  padding-left: 0;
  padding-right: 0;
  font-size: 0.8125rem;
}

.btn--ghost:hover {
  color: var(--color-text);
}

.btn--ghost .arrow {
  transition: transform var(--transition);
}

.btn--ghost:hover .arrow {
  transform: translateX(4px);
}

/* --- Cards --- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: all var(--transition);
}

.card:hover {
  border-color: var(--color-accent-border);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

.card__icon {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent-glow);
  border: 1px solid var(--color-accent-border);
  border-radius: var(--radius);
  margin-bottom: 1.25rem;
  color: var(--color-accent);
}

.card__title {
  font-family: var(--font-heading);
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 0.625rem;
  color: var(--color-text);
}

.card__text {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

.card--featured {
  border-left: 2px solid var(--color-accent);
}

/* --- Capabilities Bar --- */
.capabilities {
  padding: var(--space-md) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-alt);
}

.capabilities__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  text-align: center;
}

.capabilities__item {
  padding: 0.75rem;
}

.capabilities__number {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1;
  margin-bottom: 0.5rem;
}

.capabilities__label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  line-height: 1.4;
}

@media (max-width: 768px) {
  .capabilities__grid {
    grid-template-columns: repeat(2, 1fr) !important;
  }
}

@media (max-width: 480px) {
  .capabilities__grid {
    grid-template-columns: 1fr !important;
  }
}

/* --- Timeline --- */
.timeline {
  position: relative;
  padding-left: 2rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--color-accent), var(--color-border));
}

.timeline__item {
  position: relative;
  padding-bottom: 3rem;
}

.timeline__item:last-child {
  padding-bottom: 0;
}

.timeline__item::before {
  content: '';
  position: absolute;
  left: -2rem;
  top: 0.5rem;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 8px var(--color-accent);
  transform: translateX(-3.5px);
}

.timeline__date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-accent);
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.timeline__title {
  font-size: 1.375rem;
  margin-bottom: 0.25rem;
}

.timeline__org {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
  font-weight: 500;
}

.timeline__desc {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.timeline__desc ul {
  list-style: none;
  padding: 0;
  margin-top: 0.75rem;
}

.timeline__desc ul li {
  padding-left: 1.25rem;
  position: relative;
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
}

.timeline__desc ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 1px;
  background: var(--color-accent);
}

/* --- Skill Tags --- */
.skill-category {
  margin-bottom: 2.5rem;
}

.skill-category__title {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  letter-spacing: 0.02em;
}

.skill-tag {
  display: inline-block;
  padding: 0.375rem 0.875rem;
  margin: 0 0.375rem 0.375rem 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 100px;
  transition: all var(--transition);
}

.skill-tag:hover {
  border-color: var(--color-accent-border);
  color: var(--color-accent);
  background: var(--color-accent-glow);
}

.skill-tag--highlight {
  background: var(--color-accent-glow);
  color: var(--color-accent);
  border-color: var(--color-accent-border);
}

.skill-tag--highlight:hover {
  background: var(--color-accent);
  color: var(--color-primary);
  border-color: var(--color-accent);
}

/* --- Page Header --- */
.page-header {
  padding: calc(64px + var(--space-xl)) 0 var(--space-lg);
  background: var(--color-bg-alt);
  border-bottom: 1px solid var(--color-border);
  position: relative;
}

.page-header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-accent-border), transparent);
}

.page-header .overline {
  margin-bottom: 1rem;
}

.page-header h1 {
  margin-bottom: 1rem;
}

.page-header .lead {
  max-width: 600px;
}

/* --- Divider --- */
.divider {
  width: 48px;
  height: 2px;
  background: var(--color-accent);
  border: none;
  margin: 1.5rem 0;
  box-shadow: 0 0 8px var(--color-accent-glow);
}

/* --- Quote --- */
.quote {
  padding: var(--space-xl) 0;
  text-align: center;
}

.quote blockquote {
  font-family: var(--font-heading);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-style: italic;
  color: var(--color-text);
  line-height: 1.5;
  max-width: 700px;
  margin: 0 auto 1rem;
}

.quote cite {
  font-family: var(--font-mono);
  font-style: normal;
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  letter-spacing: 0.05em;
}

/* --- Blog / Insights --- */
.insight-card {
  padding: 2rem 0;
  border-bottom: 1px solid var(--color-border);
  transition: all var(--transition);
}

.insight-card:first-child {
  padding-top: 0;
}

.insight-card__date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.insight-card__title {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.insight-card__title a {
  color: var(--color-text);
}

.insight-card__title a:hover {
  color: var(--color-accent);
}

.insight-card__excerpt {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin-bottom: 0;
}

/* --- Contact --- */
.contact-info {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}

.contact-detail {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.contact-detail__icon {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent-glow);
  border: 1px solid var(--color-accent-border);
  border-radius: var(--radius);
  color: var(--color-accent);
  flex-shrink: 0;
}

.contact-detail__label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: 0.25rem;
}

.contact-detail__value {
  font-size: 0.9375rem;
  color: var(--color-text);
  margin-bottom: 0;
}

@media (max-width: 768px) {
  .contact-info {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

/* --- Footer --- */
.site-footer {
  padding: var(--space-lg) 0;
  background: var(--color-bg-dark);
  color: var(--color-text-muted);
  font-size: 0.8125rem;
  border-top: 1px solid var(--color-border);
}

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

.site-footer a {
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.site-footer a:hover {
  color: var(--color-accent);
}

.footer-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.footer-links a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
}

/* --- Executive Impact Strip --- */
.impact-strip {
  padding: var(--space-md) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-alt);
}

.impact-strip__grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1.5rem;
  text-align: center;
}

.impact-strip__item {
  padding: 1rem 0.5rem;
}

.impact-strip__value {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1;
  margin-bottom: 0.375rem;
}

.impact-strip__label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  line-height: 1.4;
}

@media (max-width: 768px) {
  .impact-strip__grid {
    grid-template-columns: repeat(3, 1fr) !important;
  }
}

@media (max-width: 480px) {
  .impact-strip__grid {
    grid-template-columns: repeat(2, 1fr) !important;
  }
  .impact-strip__value {
    font-size: 1.5rem;
  }
}

/* --- Executive Transformation Cards --- */
.transform-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: all var(--transition);
}

.transform-card:hover {
  border-color: var(--color-accent-border);
  box-shadow: var(--shadow-glow);
}

.transform-card__metric {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: 0.5rem;
}

.transform-card__title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.transform-card__desc {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

/* --- Principle List --- */
.principle {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--color-border);
}

.principle:last-child {
  border-bottom: none;
}

.principle__heading {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 0.375rem;
}

.principle__text {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  margin-bottom: 0;
  line-height: 1.7;
}

/* --- Domain Block (Expertise) --- */
.domain-block {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 1.25rem;
  transition: all var(--transition);
}

.domain-block:hover {
  border-color: var(--color-accent-border);
}

.domain-block__title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.75rem;
}

.domain-block__desc {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: 1rem;
}

/* --- Utility --- */
.text-center { text-align: center; }
.text-accent { color: var(--color-accent); }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-6 { margin-bottom: 3rem; }
.mt-4 { margin-top: 2rem; }
.mt-6 { margin-top: 3rem; }
.pt-0 { padding-top: 0; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}

/* --- Animations --- */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Inline list styling for dark theme --- */
section ul li span[style*="background: var(--color-accent)"] {
  box-shadow: 0 0 4px var(--color-accent-glow);
}

/* --- Lab Article --- */
.lab-article__layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 3.5rem;
  align-items: start;
}

.lab-article__toc {
  position: sticky;
  top: 88px;
  align-self: start;
  font-size: 0.8125rem;
}

.lab-article__toc-title {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: 0.875rem;
  padding-bottom: 0.625rem;
  border-bottom: 1px solid var(--color-border);
}

.lab-article__toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.lab-article__toc-list li {
  margin-bottom: 0.25rem;
}

.lab-article__toc-list a {
  display: block;
  padding: 0.375rem 0 0.375rem 0.875rem;
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  border-left: 2px solid transparent;
  transition: all var(--transition);
  line-height: 1.4;
}

.lab-article__toc-list a:hover,
.lab-article__toc-list a.active {
  color: var(--color-accent);
  border-left-color: var(--color-accent);
  background: var(--color-accent-glow);
}

.lab-article__body h2 {
  font-size: 1.625rem;
  margin-top: 3.5rem;
  margin-bottom: 1rem;
  padding-top: 1rem;
  scroll-margin-top: 88px;
}

.lab-article__body h2:first-child {
  margin-top: 0;
  padding-top: 0;
}

.lab-article__body h3 {
  font-size: 1.1875rem;
  margin-top: 2.25rem;
  margin-bottom: 0.75rem;
  scroll-margin-top: 88px;
}

.lab-article__body h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.lab-article__body p {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.75;
}

.lab-article__body > ul,
.lab-article__body > ol {
  margin: 0 0 1.5rem 0;
  padding-left: 1.25rem;
  color: var(--color-text-secondary);
}

.lab-article__body > ul li,
.lab-article__body > ol li {
  margin-bottom: 0.5rem;
  line-height: 1.7;
  font-size: 0.9375rem;
}

.lab-article__body > ul li::marker {
  color: var(--color-accent);
}

.lab-article__body > ol li::marker {
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-weight: 600;
}

.lab-article__body strong {
  color: var(--color-text);
  font-weight: 600;
}

/* Article meta strip */
.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-bottom: 2rem;
  padding: 0.875rem 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.article-meta__item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.article-meta__item strong {
  color: var(--color-text-secondary);
  font-weight: 500;
}

/* Code blocks */
.code-block {
  margin: 1.5rem 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--color-bg-dark);
}

.code-block__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0.875rem;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
}

.code-block__lang {
  color: var(--color-accent);
}

.code-block pre {
  margin: 0;
  padding: 1rem 1.25rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  line-height: 1.65;
  color: var(--color-text);
  background: transparent;
}

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

.lab-article__body :not(pre) > code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 0.1rem 0.4rem;
  color: var(--color-accent);
  white-space: nowrap;
}

/* Code syntax tokens */
.tok-c { color: var(--color-text-muted); font-style: italic; }
.tok-k { color: var(--color-purple); font-weight: 500; }
.tok-s { color: var(--color-accent); }
.tok-n { color: #fbbf24; }
.tok-p { color: var(--color-blue); }
.tok-t { color: #f472b6; }

/* Callouts */
.callout {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
}

.callout__title {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  margin-bottom: 0.4rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.callout p {
  margin-bottom: 0;
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.callout p + p {
  margin-top: 0.75rem;
}

.callout--warn { border-left-color: #f59e0b; }
.callout--warn .callout__title { color: #f59e0b; }

.callout--danger { border-left-color: #ef4444; }
.callout--danger .callout__title { color: #ef4444; }

.callout--note { border-left-color: var(--color-blue); }
.callout--note .callout__title { color: var(--color-blue); }

/* Step list */
.step-list {
  counter-reset: step;
  list-style: none;
  padding-left: 0;
  margin: 1.5rem 0;
}

.step-list > li {
  counter-increment: step;
  position: relative;
  padding-left: 3.25rem;
  margin-bottom: 2.25rem;
}

.step-list > li::before {
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-accent);
  background: var(--color-accent-glow);
  border: 1px solid var(--color-accent-border);
  border-radius: var(--radius);
  padding: 0.375rem 0.5rem;
  line-height: 1;
  min-width: 2.5rem;
  text-align: center;
}

.step-list > li > h4 {
  margin-top: 0.125rem;
  margin-bottom: 0.625rem;
}

.step-list > li > p {
  font-size: 0.9375rem;
}

/* Diagram container */
.diagram {
  background: linear-gradient(180deg, var(--color-bg-dark) 0%, var(--color-secondary) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem 1.5rem 1.25rem;
  margin: 2rem 0;
  overflow-x: auto;
}

.diagram__inner {
  display: flex;
  justify-content: center;
  min-width: 600px;
}

.diagram svg {
  max-width: 100%;
  height: auto;
  display: block;
}

.diagram__caption {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-top: 1.25rem;
  text-align: center;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}

/* Tables */
.lab-article__body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.875rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}

.lab-article__body th {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  background: var(--color-bg-alt);
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
}

.lab-article__body td {
  padding: 0.75rem 1rem;
  color: var(--color-text-secondary);
  border-bottom: 1px solid var(--color-border-light);
  vertical-align: top;
}

.lab-article__body tr:last-child td {
  border-bottom: none;
}

.lab-article__body td code {
  font-size: 0.8125rem;
}

/* Article footer / next-prev */
.article-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
}

.article-nav a {
  display: block;
  padding: 1.25rem 1.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  text-decoration: none;
  transition: all var(--transition);
}

.article-nav a:hover {
  border-color: var(--color-accent-border);
  background: var(--color-accent-glow);
}

.article-nav__label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

.article-nav__title {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text);
}

.article-nav a:hover .article-nav__title {
  color: var(--color-accent);
}

.article-nav__next {
  text-align: right;
}

@media (max-width: 1024px) {
  .lab-article__layout {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  .lab-article__toc {
    position: static;
    display: none;
  }
  .article-nav {
    grid-template-columns: 1fr;
  }
  .article-nav__next {
    text-align: left;
  }
}

/* --- Article list (category page) --- */
.article-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: 2rem;
}

.article-list__item {
  display: block;
  text-decoration: none;
  padding: 2rem 0;
  border-bottom: 1px solid var(--color-border);
  transition: padding var(--transition);
  position: relative;
}

.article-list__item:first-child { padding-top: 0; }
.article-list__item:last-child { border-bottom: none; }

.article-list__item:hover { padding-left: 0.5rem; }

.article-list__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  margin-bottom: 0.625rem;
}

.article-list__meta-divider { color: var(--color-text-muted); }

.article-list__title {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 0.625rem;
  color: var(--color-text);
  transition: color var(--transition);
  letter-spacing: -0.02em;
}

.article-list__item:hover .article-list__title {
  color: var(--color-accent);
}

.article-list__excerpt {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
  line-height: 1.7;
}

.article-list__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
  margin-top: 0.5rem;
}

.article-list__arrow {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-accent);
  margin-top: 0.5rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: transform var(--transition);
}

.article-list__item:hover .article-list__arrow {
  transform: translateX(4px);
}

.article-list__item--soon {
  opacity: 0.55;
  pointer-events: none;
}

.article-list__item--soon .article-list__title {
  color: var(--color-text-muted);
}

.article-list__item--soon .article-list__meta {
  color: var(--color-text-muted);
}

.article-list__empty-note {
  margin-top: 3rem;
  padding: 1.5rem;
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  font-size: 0.875rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* --- Print --- */
@media print {
  .site-header, .site-footer, .hero__scroll-indicator, .menu-toggle { display: none; }
  body { font-size: 12pt; color: #000; background: #fff; }
  .page-header { padding-top: 0; background: none; border: none; }
  h1, h2, h3, h4 { color: #000; }
  p { color: #333; }
  a { color: #000; }
  .btn { border: 1px solid #000; background: none; color: #000; }
  .card { background: #fff; border-color: #ddd; }
  .skill-tag { background: #f5f5f5; color: #333; border-color: #ddd; }
  .skill-tag--highlight { background: #e8e8e8; color: #000; }
  .overline { background: none; border: none; color: #666; padding: 0; }
}