/* ==========================================================================
   Harsh Singh — Portfolio
   Design system: monochrome foundation, single restrained accent.
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&family=Newsreader:ital,opsz,wght@0,6..72,400;0,6..72,500;0,6..72,600;0,6..72,700;1,6..72,400;1,6..72,500&display=swap');

/* ---------- Tokens: Dark (default) ---------- */
:root {
  --bg:            #0b0d12;
  --bg-elevated:   #11141b;
  --bg-card:       #121620;
  --bg-card-hover: #161b27;
  --border:        #1f2532;
  --border-strong: #2a3142;
  --border-hover:  #3a4459;

  --text:          #e6e8ee;
  --text-secondary:#a8aebd;
  --text-muted:    #6b7388;

  --accent:        #7c8cff;   /* refined indigo */
  --accent-hover:  #9aa6ff;
  --accent-soft:   rgba(124, 140, 255, 0.10);
  --accent-ring:   rgba(124, 140, 255, 0.25);

  --success:       #34d399;
  --success-soft:  rgba(52, 211, 153, 0.12);
  --warning:       #fbbf24;
  --warning-soft:  rgba(251, 191, 36, 0.12);
  --violet:        #b794f6;
  --violet-soft:   rgba(183, 148, 246, 0.12);

  --radius-sm: 6px;
  --radius:    10px;
  --radius-lg: 14px;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
  --shadow:    0 8px 30px rgba(0,0,0,0.25);
  --shadow-lg: 0 20px 50px rgba(0,0,0,0.35);

  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --dur:  180ms;

  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono:  'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  --font-serif: 'Newsreader', 'Source Serif 4', Charter, 'Iowan Old Style', 'Apple Garamond', Georgia, serif;

  /* Semantic palette — recurring visual language for technical posts */
  --c-abstraction: #7c8cff;   /* indigo — generic abstractions */
  --c-perf:        #34d399;   /* green  — performance wins */
  --c-debug:       #fbbf24;   /* amber  — debugging / regressions */
  --c-instability: #f87171;   /* red    — failing CI / numerical instability */
  --c-abstraction-soft: rgba(124, 140, 255, 0.10);
  --c-perf-soft:        rgba(52, 211, 153, 0.12);
  --c-debug-soft:       rgba(251, 191, 36, 0.12);
  --c-instability-soft: rgba(248, 113, 113, 0.12);

  --container:   1120px;
  --container-prose: 680px;
  --nav-h: 68px;
}

/* ---------- Tokens: Light ---------- */
[data-theme="light"] {
  --bg:            #fafbfc;
  --bg-elevated:   #ffffff;
  --bg-card:       #ffffff;
  --bg-card-hover: #f6f7fb;
  --border:        #e6e8ee;
  --border-strong: #d6dae3;
  --border-hover:  #b8bfcc;

  --text:          #0f1419;
  --text-secondary:#4a5263;
  --text-muted:    #7a8294;

  --accent:        #4f5dc4;
  --accent-hover:  #3b48a6;
  --accent-soft:   rgba(79, 93, 196, 0.08);
  --accent-ring:   rgba(79, 93, 196, 0.20);

  --success:       #059669;
  --success-soft:  rgba(5, 150, 105, 0.10);
  --warning:       #b45309;
  --warning-soft:  rgba(180, 83, 9, 0.10);
  --violet:        #7c3aed;
  --violet-soft:   rgba(124, 58, 237, 0.10);

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow:    0 4px 24px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 20px 50px rgba(15, 23, 42, 0.10);

  --c-abstraction: #4f5dc4;
  --c-perf:        #059669;
  --c-debug:       #b45309;
  --c-instability: #b91c1c;
  --c-abstraction-soft: rgba(79, 93, 196, 0.08);
  --c-perf-soft:        rgba(5, 150, 105, 0.08);
  --c-debug-soft:       rgba(180, 83, 9, 0.08);
  --c-instability-soft: rgba(185, 28, 28, 0.08);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 16px);
  -webkit-text-size-adjust: 100%;
  overflow-x: clip;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-feature-settings: 'cv11', 'ss01', 'ss03';
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

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

a { color: inherit; text-decoration: none; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- Background ---------- */
.grid-bg {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 80px 80px;
  opacity: 0.35;
  mask-image: radial-gradient(ellipse at 50% 0%, #000 0%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse at 50% 0%, #000 0%, transparent 70%);
}
[data-theme="light"] .grid-bg { opacity: 0.6; }

/* ---------- Layout ---------- */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

section {
  padding: 96px 0;
  position: relative;
}

section + section { border-top: 1px solid var(--border); }

.section-header { text-align: left; margin-bottom: 56px; max-width: 720px; }
.section-header.center { text-align: center; margin-left: auto; margin-right: auto; }

.section-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent);
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 14px;
  display: inline-block;
}

.section-title {
  font-size: clamp(1.75rem, 3vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
  margin-bottom: 14px;
}

.section-desc {
  font-size: 1.02rem;
  color: var(--text-secondary);
  max-width: 640px;
}

/* ---------- Navbar ---------- */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  height: var(--nav-h);
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  backdrop-filter: saturate(180%) blur(16px);
  -webkit-backdrop-filter: saturate(180%) blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.navbar.scrolled { border-bottom-color: var(--border); }

.navbar .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 100%;
}

.nav-logo {
  font-family: var(--font-mono);
  font-weight: 600; font-size: 0.95rem;
  letter-spacing: -0.02em;
  color: var(--text);
  padding: 6px 0;
}

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

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.nav-links a:hover { color: var(--text); }
.nav-links a.active { color: var(--accent); }

.theme-toggle {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  width: 34px; height: 34px;
  display: inline-flex; align-items: center; justify-content: center;
  transition: all var(--dur) var(--ease);
  margin-left: 8px;
  padding: 0;
}
.theme-toggle:hover { border-color: var(--border-hover); color: var(--text); }
.theme-toggle svg { width: 16px; height: 16px; }

.mobile-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text); cursor: pointer;
  width: 38px; height: 38px;
  align-items: center; justify-content: center;
}

.mobile-actions { display: none; align-items: center; gap: 8px; }
.mobile-actions .theme-toggle { margin-left: 0; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 11px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  font-family: var(--font-sans);
  letter-spacing: -0.005em;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all var(--dur) var(--ease);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}
.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px var(--accent-ring);
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border-color: var(--border-strong);
}
.btn-outline:hover {
  border-color: var(--border-hover);
  background: var(--bg-card);
}

.btn .arrow {
  transition: transform var(--dur) var(--ease);
  display: inline-block;
}
.btn:hover .arrow { transform: translateX(2px); }

/* ---------- Hero ---------- */
.hero {
  min-height: 100vh;
  display: flex; align-items: center;
  padding: calc(var(--nav-h) + 60px) 0 80px;
  position: relative;
}

.hero > .container { width: 100%; }
.hero-content { max-width: 760px; }

.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--accent-soft);
  border: 1px solid var(--accent-ring);
  border-radius: 999px;
  padding: 5px 12px 5px 10px;
  font-size: 0.8rem;
  color: var(--accent-hover);
  font-weight: 500;
  margin-bottom: 28px;
}
.hero-badge .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
  animation: pulse 2.4s ease-in-out infinite;
}

.hero h1 {
  font-size: clamp(2.4rem, 5.5vw, 4rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.035em;
  margin-bottom: 14px;
}

.hero-title {
  font-size: clamp(1rem, 1.6vw, 1.2rem);
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 24px;
  font-family: var(--font-mono);
  min-height: 1.7em;
}
.hero-title .caret {
  display: inline-block;
  width: 2px; height: 1em;
  background: var(--accent);
  vertical-align: -2px;
  margin-left: 2px;
  animation: blink 1s steps(2, end) infinite;
}

.hero-desc {
  font-size: 1.08rem;
  color: var(--text-secondary);
  max-width: 620px;
  margin-bottom: 36px;
  line-height: 1.7;
}

.hero-ctas { display: flex; flex-wrap: wrap; gap: 10px; }

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 56px;
  align-items: start;
}

.about-text p {
  color: var(--text-secondary);
  margin-bottom: 16px;
  font-size: 1rem;
}
.about-text p:last-child { margin-bottom: 0; }
.about-text strong { color: var(--text); font-weight: 600; }

.about-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.about-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.about-card:hover { border-color: var(--border-hover); transform: translateY(-2px); }
.about-card .icon {
  width: 32px; height: 32px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
  margin-bottom: 12px;
}
.about-card .icon svg { width: 16px; height: 16px; }
.about-card h4 { font-size: 0.88rem; font-weight: 600; margin-bottom: 4px; letter-spacing: -0.01em; }
.about-card p { font-size: 0.82rem; color: var(--text-muted); line-height: 1.5; }

/* ---------- GSoC Project ---------- */
.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px;
  position: relative;
  overflow: hidden;
}
.project-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0.6;
}

.project-meta {
  display: flex; flex-wrap: wrap; gap: 8px 28px;
  margin-bottom: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}
.project-meta-item { display: flex; flex-direction: column; gap: 2px; }
.project-meta-item .label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 500;
}
.project-meta-item .value { font-weight: 500; font-size: 0.92rem; color: var(--text); }
.project-meta-item .value.status { color: var(--success); display: inline-flex; align-items: center; gap: 6px; }
.project-meta-item .value.status::before {
  content: ''; width: 6px; height: 6px; border-radius: 50%;
  background: var(--success); box-shadow: 0 0 0 3px var(--success-soft);
}

.project-overview {
  color: var(--text-secondary);
  margin-bottom: 28px;
  font-size: 1rem;
  line-height: 1.7;
}
.project-overview code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 1px 6px;
  border-radius: 4px;
  color: var(--text);
}

.project-goals h3 {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.goal-list {
  list-style: none;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px 24px;
}
.goal-list li {
  display: flex; align-items: flex-start; gap: 10px;
  font-size: 0.92rem;
  color: var(--text-secondary);
}
.goal-list li::before {
  content: '';
  width: 14px; height: 14px;
  margin-top: 4px;
  flex-shrink: 0;
  background: var(--accent-soft);
  border-radius: 4px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='none' stroke='%237c8cff' stroke-width='2.5'%3E%3Cpath d='M3 8l3.5 3.5L13 5'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: center;
}

.mentors-list {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}
.mentors-list strong {
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
  margin-right: 6px;
}
.mentor-tag {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 12px;
  font-size: 0.82rem;
  color: var(--text);
  font-weight: 500;
}

.tech-highlights {
  display: flex; flex-wrap: wrap; gap: 6px;
  margin-top: 20px;
}
.tech-tag {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 10px;
  font-size: 0.76rem;
  color: var(--text-secondary);
  font-weight: 500;
  font-family: var(--font-mono);
  letter-spacing: -0.01em;
}

/* ---------- Timeline ---------- */
.timeline-wrap { margin-top: 64px; }
.timeline-wrap > h3 {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  text-align: center;
  margin-bottom: 36px;
  color: var(--text);
}

.timeline {
  position: relative;
  max-width: 720px;
  margin: 0 auto;
  padding-left: 32px;
}
.timeline::before {
  content: '';
  position: absolute; left: 7px; top: 8px; bottom: 8px;
  width: 1px;
  background: linear-gradient(to bottom, var(--accent) 0%, var(--border) 30%, var(--border) 100%);
}

.timeline-item { position: relative; margin-bottom: 24px; }
.timeline-item:last-child { margin-bottom: 0; }

.timeline-dot {
  position: absolute; left: -32px; top: 10px;
  width: 15px; height: 15px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--border-strong);
  z-index: 1;
}
.timeline-item.active .timeline-dot {
  border-color: var(--accent);
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.timeline-content {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  transition: border-color var(--dur) var(--ease);
}
.timeline-content:hover { border-color: var(--border-hover); }
.timeline-date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  font-weight: 500;
  margin-bottom: 4px;
  letter-spacing: 0.02em;
}
.timeline-content h4 { font-size: 0.98rem; font-weight: 600; margin-bottom: 4px; letter-spacing: -0.01em; }
.timeline-content p { font-size: 0.88rem; color: var(--text-secondary); line-height: 1.6; }

/* ---------- Contributions ---------- */
.contrib-tabs {
  display: inline-flex;
  gap: 2px;
  margin-bottom: 32px;
  padding: 4px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.contrib-tab {
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  padding: 7px 14px;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--dur) var(--ease);
  font-family: var(--font-sans);
}
.contrib-tab:hover { color: var(--text); }
.contrib-tab.active {
  background: var(--bg-elevated);
  color: var(--text);
  box-shadow: var(--shadow-sm);
}

.contrib-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 12px;
}

.pr-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  transition: all var(--dur) var(--ease);
  display: block;
  color: var(--text);
  position: relative;
}
.pr-card:hover {
  border-color: var(--border-hover);
  background: var(--bg-card-hover);
  transform: translateY(-1px);
}

.pr-card-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 10px;
  gap: 12px;
}
.pr-number {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 500;
}
.pr-status {
  font-size: 0.7rem;
  font-weight: 500;
  padding: 2px 8px;
  border-radius: 999px;
  letter-spacing: 0.02em;
  display: inline-flex; align-items: center; gap: 5px;
}
.pr-status::before {
  content: ''; width: 5px; height: 5px; border-radius: 50%;
}
.pr-status.merged { background: var(--success-soft); color: var(--success); }
.pr-status.merged::before { background: var(--success); }
.pr-status.open { background: var(--warning-soft); color: var(--warning); }
.pr-status.open::before { background: var(--warning); }

.pr-card h4 {
  font-size: 0.92rem;
  font-weight: 500;
  line-height: 1.45;
  color: var(--text);
  letter-spacing: -0.005em;
}

/* ---------- Blog ---------- */
.blog-filters {
  display: flex; gap: 6px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}
.blog-filter {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--dur) var(--ease);
  font-family: var(--font-sans);
}
.blog-filter:hover { color: var(--text); border-color: var(--border-hover); }
.blog-filter.active {
  background: var(--text);
  color: var(--bg);
  border-color: var(--text);
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 16px;
}

.blog-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--dur) var(--ease);
  display: flex; flex-direction: column;
  color: var(--text);
}
.blog-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.blog-card-body { padding: 22px; flex: 1; }

.blog-card-meta {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 14px;
  font-size: 0.76rem;
  color: var(--text-muted);
}

.blog-category {
  background: var(--accent-soft);
  color: var(--accent);
  padding: 3px 9px;
  border-radius: 999px;
  font-weight: 500;
  font-size: 0.72rem;
  letter-spacing: 0.01em;
}
.blog-card[data-cat="numerical"] .blog-category { background: var(--violet-soft); color: var(--violet); }
.blog-card[data-cat="julia"]     .blog-category { background: var(--accent-soft); color: var(--accent); }
.blog-card[data-cat="gsoc"]      .blog-category { background: var(--success-soft); color: var(--success); }
.blog-card[data-cat="opensource"] .blog-category { background: var(--warning-soft); color: var(--warning); }

.blog-card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 8px;
  line-height: 1.4;
  letter-spacing: -0.015em;
  color: var(--text);
}
.blog-card p { font-size: 0.88rem; color: var(--text-secondary); line-height: 1.6; }

.blog-card-footer {
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px 22px;
  border-top: 1px solid var(--border);
  font-size: 0.76rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* ---------- Skills ---------- */
.skills-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }

.skill-category h3 {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 18px;
}

.skill-tags { display: flex; flex-wrap: wrap; gap: 8px; }

.skill-tag {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 14px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text);
  transition: all var(--dur) var(--ease);
  display: inline-flex; align-items: center; gap: 8px;
}
.skill-tag:hover { border-color: var(--border-hover); transform: translateY(-1px); }

/* ---------- Achievements ---------- */
.achievements-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 14px;
}
.achievement-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  transition: all var(--dur) var(--ease);
}
.achievement-card:hover { border-color: var(--border-hover); transform: translateY(-2px); }
.achievement-card .ach-icon {
  width: 36px; height: 36px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
  margin-bottom: 14px;
}
.achievement-card .ach-icon svg { width: 18px; height: 18px; }
.achievement-card h4 {
  font-size: 0.95rem; font-weight: 600;
  margin-bottom: 4px; letter-spacing: -0.01em;
}
.achievement-card p { font-size: 0.83rem; color: var(--text-secondary); line-height: 1.5; }

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
  max-width: 900px;
}

.contact-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-decoration: none;
  transition: all var(--dur) var(--ease);
  display: flex; flex-direction: column; gap: 10px;
  color: var(--text);
}
.contact-card:hover { border-color: var(--border-hover); transform: translateY(-2px); background: var(--bg-card-hover); }
.contact-card .contact-icon {
  width: 32px; height: 32px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
}
.contact-card .contact-icon svg { width: 16px; height: 16px; }
.contact-card h4 { font-size: 0.88rem; font-weight: 600; letter-spacing: -0.01em; }
.contact-card p { font-size: 0.78rem; color: var(--text-muted); word-break: break-all; font-family: var(--font-mono); }

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--border);
  padding: 36px 0;
}
.footer .container {
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px;
}
.footer p { font-size: 0.82rem; color: var(--text-muted); }
.footer a { color: var(--text); font-weight: 500; }
.footer a:hover { color: var(--accent); }

/* ---------- GitHub Activity Graph ---------- */
.github-graph {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-top: 40px;
  overflow-x: auto;
}
.graph-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 16px;
  font-size: 0.82rem;
}
.graph-header .label {
  font-family: var(--font-mono);
  color: var(--text-secondary);
  font-weight: 500;
}
.graph-legend {
  display: inline-flex; align-items: center; gap: 6px;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-family: var(--font-mono);
}
.graph-legend .swatches { display: inline-flex; gap: 3px; }
.graph-legend .sw { width: 10px; height: 10px; border-radius: 2px; background: var(--bg-elevated); border: 1px solid var(--border); }
.graph-legend .sw.l1 { background: rgba(124,140,255,0.20); border-color: transparent; }
.graph-legend .sw.l2 { background: rgba(124,140,255,0.40); border-color: transparent; }
.graph-legend .sw.l3 { background: rgba(124,140,255,0.65); border-color: transparent; }
.graph-legend .sw.l4 { background: rgba(124,140,255,0.90); border-color: transparent; }

.graph-grid {
  display: grid;
  grid-template-columns: repeat(52, 12px);
  grid-template-rows: repeat(7, 12px);
  gap: 3px;
}
.graph-cell {
  width: 12px; height: 12px; border-radius: 2px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
}
.graph-cell.l1 { background: rgba(124,140,255,0.20); border-color: transparent; }
.graph-cell.l2 { background: rgba(124,140,255,0.40); border-color: transparent; }
.graph-cell.l3 { background: rgba(124,140,255,0.65); border-color: transparent; }
.graph-cell.l4 { background: rgba(124,140,255,0.90); border-color: transparent; }
[data-theme="light"] .graph-cell.l1 { background: rgba(79,93,196,0.18); }
[data-theme="light"] .graph-cell.l2 { background: rgba(79,93,196,0.38); }
[data-theme="light"] .graph-cell.l3 { background: rgba(79,93,196,0.62); }
[data-theme="light"] .graph-cell.l4 { background: rgba(79,93,196,0.88); }
[data-theme="light"] .graph-legend .sw.l1 { background: rgba(79,93,196,0.18); }
[data-theme="light"] .graph-legend .sw.l2 { background: rgba(79,93,196,0.38); }
[data-theme="light"] .graph-legend .sw.l3 { background: rgba(79,93,196,0.62); }
[data-theme="light"] .graph-legend .sw.l4 { background: rgba(79,93,196,0.88); }

/* ==========================================================================
   Blog post (editorial)
   ========================================================================== */

.blog-post {
  max-width: var(--container-prose);
  margin: 0 auto;
  padding: calc(var(--nav-h) + 72px) 24px 96px;
}

.blog-post-back {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 36px;
  transition: color var(--dur) var(--ease);
}
.blog-post-back:hover { color: var(--accent); }

.blog-post-header {
  margin-bottom: 56px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border);
}
.blog-post-header h1 {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 4.4vw, 2.9rem);
  font-weight: 600;
  font-optical-sizing: auto;
  letter-spacing: -0.018em;
  line-height: 1.12;
  color: var(--text);
  margin-bottom: 20px;
}
.blog-post-meta {
  display: flex; gap: 20px; flex-wrap: wrap; align-items: center;
  color: var(--text-muted);
  font-size: 0.82rem;
  font-family: var(--font-mono);
  letter-spacing: 0.01em;
}
.blog-post-meta .blog-category { font-family: var(--font-sans); }

/* ---------- Prose ---------- */
.blog-post-content {
  font-family: var(--font-serif);
  font-size: 1.18rem;
  line-height: 1.72;
  color: var(--text);
  font-optical-sizing: auto;
  font-feature-settings: 'kern', 'liga', 'onum';
}
[data-theme="light"] .blog-post-content { color: #1a1f2b; }

.blog-post-content > * + * { margin-top: 1.1em; }
.blog-post-content > h2 { margin-top: 2.6em; }
.blog-post-content > h3 { margin-top: 2em; }
.blog-post-content > pre,
.blog-post-content > figure,
.blog-post-content > .callout,
.blog-post-content > .code-figure { margin-top: 2em; margin-bottom: 2em; }

.blog-post-content h2 {
  font-family: var(--font-serif);
  font-size: 1.7rem;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.25;
  color: var(--text);
}
.blog-post-content h3 {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 600;
  letter-spacing: -0.012em;
  line-height: 1.3;
  color: var(--text);
}
.blog-post-content h4 {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-top: 2em;
  margin-bottom: 0.6em;
}

.blog-post-content p { margin: 0; }
.blog-post-content p + p { margin-top: 1.1em; }

.blog-post-content ul,
.blog-post-content ol {
  padding-left: 1.4em;
}
.blog-post-content li { margin-bottom: 0.4em; }
.blog-post-content li::marker { color: var(--text-muted); }

.blog-post-content a {
  color: var(--text);
  text-decoration: underline;
  text-decoration-color: var(--accent-ring);
  text-decoration-thickness: 1.5px;
  text-underline-offset: 3px;
  transition: text-decoration-color var(--dur) var(--ease);
}
.blog-post-content a:hover { text-decoration-color: var(--accent); }

.blog-post-content strong { font-weight: 600; color: var(--text); }
.blog-post-content em { font-style: italic; }

/* Drop cap on first paragraph after the lead (opt-in via .lead) */
.blog-post-content .lead {
  font-size: 1.32rem;
  line-height: 1.55;
  color: var(--text);
  font-weight: 400;
}
[data-theme="light"] .blog-post-content .lead { color: #1a1f2b; }

/* ---------- Inline code ---------- */
.blog-post-content code {
  font-family: var(--font-mono);
  font-size: 0.84em;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 1px 6px;
  border-radius: 4px;
  color: var(--text);
  font-feature-settings: 'calt', 'liga';
}

/* ---------- Blockquote ---------- */
.blog-post-content blockquote {
  border-left: 2px solid var(--border-strong);
  padding: 4px 0 4px 24px;
  margin-left: 0;
  font-style: italic;
  color: var(--text-secondary);
  font-size: 1.05em;
}
.blog-post-content blockquote p { margin: 0; }
.blog-post-content blockquote p + p { margin-top: 0.8em; }
.blog-post-content blockquote cite {
  display: block;
  margin-top: 12px;
  font-style: normal;
  font-family: var(--font-sans);
  font-size: 0.82rem;
  color: var(--text-muted);
  letter-spacing: 0.01em;
}
.blog-post-content blockquote cite::before { content: '— '; }

/* ==========================================================================
   Code blocks as figures
   ========================================================================== */

.blog-post-content pre {
  background: #0d1117;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 22px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.86rem;
  line-height: 1.7;
  position: relative;
  color: #c9d1d9;
}
[data-theme="light"] .blog-post-content pre {
  background: #f6f7fb;
  border-color: var(--border);
  color: #1f2532;
}
.blog-post-content pre code {
  background: none;
  padding: 0;
  border: none;
  color: inherit;
  font-size: inherit;
}

/* Highlighted lines (apply class="hl" to a wrapping span on the line, or use data-line-highlights via JS) */
.blog-post-content pre .hl {
  display: block;
  margin: 0 -22px;
  padding: 0 22px;
  background: var(--accent-soft);
  border-left: 2px solid var(--accent);
  padding-left: 20px;
}

/* The proper figure wrapper for code: filename bar + caption */
.code-figure {
  display: flex; flex-direction: column;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg-card);
}
.code-figure-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 14px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--text-secondary);
}
.code-figure-head .filename {
  display: inline-flex; align-items: center; gap: 8px;
}
.code-figure-head .filename::before {
  content: '';
  width: 10px; height: 10px;
  border-radius: 2px;
  background: var(--accent);
  opacity: 0.7;
}
.code-figure-head .lang {
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 2px 7px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-card);
}
.code-figure pre {
  margin: 0 !important;
  border: none !important;
  border-radius: 0 !important;
  background: var(--bg-card) !important;
}
[data-theme="light"] .code-figure pre { background: #fbfbfd !important; color: #1f2532 !important; }
.code-figure figcaption {
  padding: 10px 16px;
  border-top: 1px solid var(--border);
  background: var(--bg-elevated);
  font-family: var(--font-sans);
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.55;
}
.code-figure figcaption b { color: var(--text); font-weight: 600; }

/* Copy button — always visible inside code figures, hover-only on plain pre */
.copy-btn {
  position: absolute; top: 8px; right: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 3px 9px;
  font-size: 0.7rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--dur) var(--ease);
  font-family: var(--font-sans);
  letter-spacing: 0.02em;
  opacity: 0;
}
pre:hover .copy-btn,
.code-figure:hover .copy-btn { opacity: 1; }
.copy-btn:hover { border-color: var(--border-hover); color: var(--text); }
.code-figure .copy-btn { top: 6px; right: 8px; background: transparent; border-color: transparent; }
.code-figure .copy-btn:hover { background: var(--bg-card); border-color: var(--border); }

/* ==========================================================================
   Figures & captions (diagrams, images, tables)
   ========================================================================== */

.blog-post-content figure {
  margin: 0;
}
.blog-post-content figure img,
.blog-post-content figure svg {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-card);
}
.blog-post-content figcaption {
  margin-top: 12px;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  line-height: 1.55;
  color: var(--text-muted);
  text-align: center;
}
.blog-post-content figcaption .fig-num {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-right: 6px;
  letter-spacing: 0.04em;
}

/* ==========================================================================
   Callouts — semantic visual language
   indigo = abstractions · green = perf · amber = debug · red = instability
   ========================================================================== */

.callout {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  padding: 18px 20px;
  border: 1px solid var(--border);
  border-left: 3px solid var(--text-muted);
  border-radius: var(--radius);
  background: var(--bg-card);
  font-family: var(--font-sans);
  font-size: 0.96rem;
  line-height: 1.6;
  color: var(--text);
}
.callout .callout-icon {
  width: 22px; height: 22px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 6px;
  flex-shrink: 0;
  margin-top: 1px;
  background: var(--bg-elevated);
  color: var(--text-muted);
}
.callout .callout-icon svg { width: 14px; height: 14px; }
.callout .callout-body > :first-child { margin-top: 0; }
.callout .callout-body > :last-child { margin-bottom: 0; }
.callout .callout-body p + p { margin-top: 0.6em; }
.callout .callout-title {
  font-family: var(--font-sans);
  font-size: 0.74rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  display: block;
  margin-bottom: 4px;
  color: var(--text-muted);
}
.callout code {
  background: color-mix(in srgb, var(--bg-elevated) 70%, transparent);
}

.callout.abstraction { border-left-color: var(--c-abstraction); background: color-mix(in srgb, var(--c-abstraction-soft) 60%, var(--bg-card)); }
.callout.abstraction .callout-icon  { background: var(--c-abstraction-soft); color: var(--c-abstraction); }
.callout.abstraction .callout-title { color: var(--c-abstraction); }

.callout.perf { border-left-color: var(--c-perf); background: color-mix(in srgb, var(--c-perf-soft) 60%, var(--bg-card)); }
.callout.perf .callout-icon  { background: var(--c-perf-soft); color: var(--c-perf); }
.callout.perf .callout-title { color: var(--c-perf); }

.callout.debug { border-left-color: var(--c-debug); background: color-mix(in srgb, var(--c-debug-soft) 60%, var(--bg-card)); }
.callout.debug .callout-icon  { background: var(--c-debug-soft); color: var(--c-debug); }
.callout.debug .callout-title { color: var(--c-debug); }

.callout.instability { border-left-color: var(--c-instability); background: color-mix(in srgb, var(--c-instability-soft) 60%, var(--bg-card)); }
.callout.instability .callout-icon  { background: var(--c-instability-soft); color: var(--c-instability); }
.callout.instability .callout-title { color: var(--c-instability); }

/* ==========================================================================
   Sidenotes — float to the right gutter on wide screens, inline on narrow
   ========================================================================== */
.sidenote {
  display: block;
  font-family: var(--font-sans);
  font-size: 0.82rem;
  line-height: 1.55;
  color: var(--text-secondary);
  background: var(--bg-elevated);
  border-left: 2px solid var(--border-strong);
  padding: 10px 14px;
  margin: 16px 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
@media (min-width: 1100px) {
  .blog-post-content { position: relative; }
  .sidenote {
    float: right;
    clear: right;
    width: 220px;
    margin: 4px -260px 16px 24px;
    background: transparent;
    border-left: none;
    padding: 0 0 0 16px;
    border-left: 1px solid var(--border);
  }
}

/* ==========================================================================
   KaTeX — keep long equations scrollable on narrow screens
   ========================================================================== */
.blog-post-content .katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  max-width: 100%;
  margin: 1.6em 0;
  padding: 6px 2px;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}
.blog-post-content .katex-display > .katex { white-space: nowrap; }
.blog-post-content .katex { font-size: 1.05em; }

/* Make inline math wrap to the next line on overflow instead of clipping */
.blog-post-content .katex { max-width: 100%; }

@media (max-width: 640px) {
  .blog-post-content .katex { font-size: 0.95em; }
  .blog-post-content .katex-display { font-size: 0.95em; }
}

/* Subtle fade on the right edge to hint at horizontal scroll */
.blog-post-content .katex-display {
  background:
    linear-gradient(to right, var(--bg) 0%, transparent 8px),
    linear-gradient(to left,  var(--bg) 0%, transparent 8px) right,
    linear-gradient(to right, rgba(0,0,0,0.08), transparent 12px),
    linear-gradient(to left,  rgba(0,0,0,0.08), transparent 12px) right;
  background-repeat: no-repeat;
  background-size: 24px 100%, 24px 100%, 12px 100%, 12px 100%;
  background-attachment: local, local, scroll, scroll;
}

/* ==========================================================================
   Diagram primitives — inline SVG, theme-aware
   ==========================================================================
   Authoring rules:
   - Use viewBox; never fixed width/height on the SVG element itself.
   - Stroke/fill colors should reference --c-abstraction / --c-perf etc.
   - Text uses .diag-label (sans) or .diag-mono (monospace).
   - Wrap diagrams in <figure class="diagram"> for consistent spacing.
   ========================================================================== */

.blog-post-content .diagram {
  margin: 2em 0;
}
.blog-post-content .diagram > svg {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  overflow: visible;
}
[data-theme="light"] .blog-post-content .diagram > svg {
  background: #fcfcfd;
}

/* Default diagram typography — applied to SVG text/tspan */
.blog-post-content .diagram svg text,
.blog-post-content .diagram svg tspan {
  font-family: var(--font-sans);
  fill: var(--text);
  dominant-baseline: middle;
}
.blog-post-content .diagram svg .diag-label {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: -0.005em;
}
.blog-post-content .diagram svg .diag-mono {
  font-family: var(--font-mono);
  font-size: 12px;
  fill: var(--text-secondary);
  letter-spacing: 0.01em;
}
.blog-post-content .diagram svg .diag-caps {
  font-family: var(--font-sans);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  fill: var(--text-muted);
}
.blog-post-content .diagram svg .diag-num {
  font-family: var(--font-mono);
  font-size: 11px;
  fill: var(--text-muted);
}

/* Default node + edge tokens (semantic) */
.blog-post-content .diagram svg .node {
  fill: var(--bg-elevated);
  stroke: var(--border-strong);
  stroke-width: 1;
}
.blog-post-content .diagram svg .node-abstraction { fill: var(--c-abstraction-soft); stroke: var(--c-abstraction); }
.blog-post-content .diagram svg .node-perf        { fill: var(--c-perf-soft);        stroke: var(--c-perf); }
.blog-post-content .diagram svg .node-debug       { fill: var(--c-debug-soft);       stroke: var(--c-debug); }
.blog-post-content .diagram svg .node-instability { fill: var(--c-instability-soft); stroke: var(--c-instability); }

.blog-post-content .diagram svg .edge {
  fill: none;
  stroke: var(--border-hover);
  stroke-width: 1.5;
}
.blog-post-content .diagram svg .edge-dashed { stroke-dasharray: 4 4; }
.blog-post-content .diagram svg .edge-abstraction { stroke: var(--c-abstraction); }
.blog-post-content .diagram svg .edge-perf        { stroke: var(--c-perf); }
.blog-post-content .diagram svg .edge-debug       { stroke: var(--c-debug); }
.blog-post-content .diagram svg .edge-instability { stroke: var(--c-instability); }

/* Bar primitives for benchmark visuals */
.blog-post-content .diagram svg .bar-bg { fill: var(--bg-elevated); }
.blog-post-content .diagram svg .bar-track { fill: var(--border); }

/* ==========================================================================
   Tables
   ========================================================================== */
.blog-post-content table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-sans);
  font-size: 0.92rem;
  margin: 2em 0;
}
.blog-post-content thead th {
  text-align: left;
  font-size: 0.74rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 10px 12px;
  border-bottom: 1px solid var(--border-strong);
}
.blog-post-content tbody td {
  padding: 12px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}
.blog-post-content tbody tr:last-child td { border-bottom: none; }

/* ==========================================================================
   Horizontal rule — section break for prose
   ========================================================================== */
.blog-post-content hr {
  border: none;
  height: 1px;
  background: var(--border);
  margin: 3em auto;
  width: 40%;
  position: relative;
}
.blog-post-content hr::after {
  content: '∗ ∗ ∗';
  position: absolute;
  left: 50%; top: 50%;
  transform: translate(-50%, -50%);
  background: var(--bg);
  padding: 0 16px;
  color: var(--text-muted);
  font-family: var(--font-serif);
  font-size: 0.95rem;
  letter-spacing: 0.4em;
}

/* ---------- Animations ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

.hero-content > * {
  opacity: 0;
  animation: heroIn 0.7s var(--ease) forwards;
}
.hero-content > *:nth-child(1) { animation-delay: 0.05s; }
.hero-content > *:nth-child(2) { animation-delay: 0.15s; }
.hero-content > *:nth-child(3) { animation-delay: 0.25s; }
.hero-content > *:nth-child(4) { animation-delay: 0.35s; }
.hero-content > *:nth-child(5) { animation-delay: 0.45s; }

@keyframes heroIn {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%      { opacity: 0.55; transform: scale(0.9); }
}
@keyframes blink {
  0%, 100% { opacity: 1; }
  50%      { opacity: 0; }
}

@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;
  }
  .fade-in { opacity: 1; transform: none; }
  .hero-content > * { opacity: 1; }
}

/* ---------- Mobile Nav ---------- */
.mobile-nav {
  display: none;
  position: fixed; inset: var(--nav-h) 0 0 0;
  z-index: 99;
  background: color-mix(in srgb, var(--bg) 96%, transparent);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  flex-direction: column; align-items: stretch;
  padding: 24px;
  gap: 4px;
}
.mobile-nav.open { display: flex; }
.mobile-nav a {
  color: var(--text);
  font-size: 1.1rem;
  font-weight: 500;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  border-bottom: 1px solid var(--border);
}
.mobile-nav a:hover { color: var(--accent); }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .about-grid { grid-template-columns: 1fr; gap: 32px; }
  .skills-grid { grid-template-columns: 1fr; gap: 32px; }
  .goal-list { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .nav-links { display: none; }
  .mobile-toggle { display: inline-flex; }
  .mobile-actions { display: inline-flex; }
  .blog-grid, .contrib-grid { grid-template-columns: 1fr; }
  .hero { padding: calc(var(--nav-h) + 40px) 0 60px; min-height: auto; }
  .project-card { padding: 24px; }
  section { padding: 64px 0; }
  .about-cards { grid-template-columns: 1fr 1fr; }
  .section-header { margin-bottom: 40px; }
  .project-meta { gap: 12px 20px; }
  .contrib-tabs { display: flex; flex-wrap: wrap; max-width: 100%; }
  .contrib-tab { flex: 1 1 auto; text-align: center; }
  .mentors-list strong { width: 100%; margin-right: 0; margin-bottom: 4px; }
}
@media (max-width: 480px) {
  .hero-ctas .btn { flex: 1 1 auto; justify-content: center; }
  .contact-grid { grid-template-columns: 1fr 1fr; }
  .about-cards { grid-template-columns: 1fr; }
  .container { padding: 0 20px; }
}