/* AlgoVision Hub — extracted from index.html inline <style> */
.av-wrapper {
  --av-accent: #f59e0b;
  --av-red: #ef4444;
  --av-green: #10b981;
  --av-blue: #3b82f6;
  --av-purple: #8b5cf6;
  --av-bg: #0f0f1a;
  --av-card-bg: rgba(255,255,255,0.04);
  --av-border: rgba(255,255,255,0.08);
  --av-text: #e2e8f0;
  --av-muted: #94a3b8;
  --av-dim: #94a3b8;
  background: var(--av-bg);
  padding: 3rem 1.5rem;
  min-height: 100vh;
}
.av-wrapper * { box-sizing: border-box; }
.av-wrapper { color-scheme: dark; }

.av-scroll-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid var(--av-border);
  background: rgba(15,15,26,0.85);
  backdrop-filter: blur(8px);
  color: var(--av-accent);
  font-size: 1.1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity .25s, transform .25s;
  transform: translateY(8px);
  z-index: 1000;
  box-shadow: 0 2px 10px rgba(0,0,0,0.4);
}
.av-scroll-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.av-scroll-top:hover {
  background: rgba(245,158,11,0.15);
  border-color: var(--av-accent);
}
.av-hero {
  text-align: center;
  max-width: 1100px;
  margin: 0 auto 3rem;
}
.av-logo {
  font-size: 3rem;
  font-weight: 800;
  background: linear-gradient(135deg, #f59e0b, #ef4444);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.5rem;
  letter-spacing: -1px;
}
.av-tagline {
  font-size: 1.15rem;
  color: var(--av-muted);
  margin-bottom: 1rem;
  font-weight: 400;
}
.av-description {
  font-size: 0.95rem;
  color: var(--av-dim);
  line-height: 1.7;
  max-width: 850px;
  margin: 0 auto 1.5rem;
}
.av-stats {
  display: flex;
  justify-content: center;
  gap: 2.5rem;
  margin: 2rem 0;
  flex-wrap: wrap;
}
.av-stat {
  text-align: center;
}
.av-stat-num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--av-accent);
  white-space: nowrap;
  min-width: 2.25ch;
  display: inline-block;
  line-height: 1.15;
  font-variant-numeric: tabular-nums;
}
.av-stat-label {
  font-size: 0.8rem;
  color: var(--av-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
}
.av-dsa-inset {
  box-sizing: border-box;
}
@media (min-width: 1024px) {
  .av-dsa-inset {
    padding-left: 2.5rem;
    padding-right: 2.5rem;
  }
}
@media (min-width: 1280px) {
  .av-dsa-inset {
    padding-left: 4rem;
    padding-right: 4rem;
  }
}
@media (min-width: 1536px) {
  .av-dsa-inset {
    padding-left: 6rem;
    padding-right: 6rem;
  }
}
.av-features {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}
.av-dsa-lead-col {
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
  width: 100%;
  box-sizing: border-box;
}
.av-dsa-lead-copy {
  font-size: 0.95rem;
  color: #94a3b8;
  margin: 0 0 1rem;
  line-height: 1.5;
}
.av-dsa-discuss-wrap {
  margin-top: 0.35rem;
  margin-bottom: 1rem;
  text-align: left;
}
.av-feature-badge {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 2rem;
  padding: 0.5rem 1rem;
  font-size: 0.82rem;
  color: var(--av-muted);
}
.av-feature-badge i { font-size: 0.75rem; }
.av-section {
  max-width: 1200px;
  margin: 0 auto 3rem;
  scroll-margin-top: 1rem;
}
.av-section-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--av-border);
}
.av-section-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}
.av-section-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--av-text);
}
.av-section-count {
  font-size: 0.75rem;
  color: var(--av-dim);
  background: rgba(255,255,255,0.06);
  padding: 0.2rem 0.6rem;
  border-radius: 1rem;
  margin-left: auto;
}
.av-problem-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 1rem;
}
.av-problem-card {
  background: var(--av-card-bg);
  border: 1px solid var(--av-border);
  border-radius: 0.75rem;
  padding: 1.25rem;
  transition: all 0.25s ease;
  cursor: pointer;
  text-decoration: none;
  display: block;
  position: relative;
  overflow: hidden;
}
.av-problem-card:hover {
  border-color: rgba(245,158,11,0.4);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(245,158,11,0.1);
  background: rgba(245,158,11,0.04);
}
.av-problem-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  border-radius: 4px 0 0 4px;
}
.av-problem-card.easy::before { background: #10b981; }
.av-problem-card.medium::before { background: #f59e0b; }
.av-problem-card.hard::before { background: #ef4444; }
.av-problem-num {
  font-size: 0.7rem;
  color: var(--av-dim);
  margin-bottom: 0.3rem;
  font-family: monospace;
}
.av-problem-name {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--av-text);
  margin-bottom: 0.5rem;
}
.av-problem-desc {
  font-size: 0.82rem;
  color: var(--av-dim);
  line-height: 1.5;
  margin-bottom: 0.75rem;
}
.av-problem-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.75rem;
}
.av-difficulty {
  padding: 0.15rem 0.5rem;
  border-radius: 0.25rem;
  font-weight: 600;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.av-difficulty.easy { background: rgba(16,185,129,0.15); color: #10b981; }
.av-difficulty.medium { background: rgba(245,158,11,0.15); color: #f59e0b; }
.av-difficulty.hard { background: rgba(239,68,68,0.15); color: #ef4444; }
.av-technique {
  color: var(--av-dim);
  font-style: italic;
}
.av-play-icon {
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: rgba(245,158,11,0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #f59e0b;
  font-size: 0.7rem;
  transition: all 0.2s;
}
.av-problem-card:hover .av-play-icon {
  background: rgba(245,158,11,0.3);
  transform: scale(1.1);
}
.av-coming-soon {
  opacity: 0.4;
  pointer-events: none;
  position: relative;
}
.av-coming-soon::after {
  content: 'COMING SOON';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) rotate(-15deg);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--av-dim);
  letter-spacing: 2px;
  background: rgba(15,15,26,0.8);
  padding: 0.3rem 1rem;
  border-radius: 4px;
  border: 1px dashed rgba(255,255,255,0.15);
}
.av-progress-badge {
  position: absolute; top: 0.5rem; left: 0.5rem;
  font-size: 0.6rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.5px;
  padding: 0.15rem 0.45rem; border-radius: 0.25rem; z-index: 1;
}
.av-progress-badge.viewed { background: rgba(59,130,246,0.2); color: #93c5fd; }
.av-progress-badge.completed { background: rgba(16,185,129,0.2); color: #6ee7b7; }
.av-roadmap {
  max-width: 1200px;
  margin: 0 auto 2rem;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--av-border);
  border-radius: 0.75rem;
  padding: 1.5rem 2rem;
}
.av-roadmap-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--av-muted);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.av-roadmap-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 0.75rem;
}
.av-roadmap-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--av-dim);
}
.av-roadmap-item .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}
.av-roadmap-item .dot.done { background: #10b981; }
.av-roadmap-item .dot.planned { background: rgba(255,255,255,0.15); }
.av-roadmap-item.done { color: var(--av-muted); }
.av-flag-bar {
  display: flex; align-items: center; gap: 1rem; flex-wrap: wrap;
  max-width: 1200px; margin: 0 auto 2rem; padding: 1rem 1.5rem;
  background: rgba(255,255,255,0.03); border: 1px solid var(--av-border);
  border-radius: 0.75rem;
}
.av-flag-label {
  font-size: 0.8rem; font-weight: 600; color: var(--av-dim);
  text-transform: uppercase; letter-spacing: 1.5px; white-space: nowrap;
}
.av-flag-chips {
  display: flex; gap: 0.5rem; flex-wrap: wrap; align-items: center;
}
.av-flag-chip {
  display: inline-flex; align-items: center; gap: 0.4rem;
  padding: 0.4rem 1rem; border-radius: 2rem;
  font-size: 0.85rem; font-weight: 600; cursor: pointer;
  background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.12);
  color: var(--av-muted); transition: all 0.2s;
  appearance: none; -webkit-appearance: none; font-family: inherit; margin: 0;
  touch-action: manipulation;
  -webkit-tap-highlight-color: rgba(245,158,11,0.2);
}
.av-flag-chip:focus { outline: none; }
.av-flag-chip:focus-visible {
  box-shadow: 0 0 0 2px rgba(245,158,11,0.35);
}
.av-flag-chip:hover {
  background: rgba(245,158,11,0.1); border-color: rgba(245,158,11,0.3);
  color: var(--av-accent); transform: translateY(-1px);
}
.av-flag-chip.active {
  background: linear-gradient(135deg, rgba(245,158,11,0.2), rgba(239,68,68,0.15));
  border-color: var(--av-accent); color: #fcd34d;
  box-shadow: 0 0 0 2px rgba(245,158,11,0.2);
}
.av-flag-chip .av-flag-badge {
  font-size: 0.65rem; padding: 0.1rem 0.4rem; border-radius: 1rem;
  background: rgba(255,255,255,0.1); color: var(--av-dim);
}
.av-flagged {
  border: 2px solid var(--av-accent) !important;
  box-shadow: 0 0 20px rgba(245,158,11,0.2);
  position: relative;
}
.av-flagged::after {
  content: ''; position: absolute; top: 0.5rem; right: 0.5rem;
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--av-accent); box-shadow: 0 0 6px var(--av-accent);
}
.av-flagged.av-flagged-common {
  border-color: #3b82f6 !important;
  box-shadow: 0 0 20px rgba(59,130,246,0.35);
}
.av-flagged.av-flagged-common::after {
  background: #3b82f6; box-shadow: 0 0 6px #3b82f6;
}
.av-company-highlight {
  border: 2px solid rgba(16,185,129,0.6) !important;
  box-shadow: 0 0 16px rgba(16,185,129,0.15);
  position: relative;
}
.av-company-highlight::before {
  content: ''; position: absolute; top: 0.5rem; right: 0.5rem;
  width: 8px; height: 8px; border-radius: 50%;
  background: #10b981; box-shadow: 0 0 6px #10b981;
}
.av-flag-chip.common {
  border-color: rgba(59,130,246,0.4);
  color: #93c5fd;
}
.av-flag-chip.common:hover {
  background: rgba(59,130,246,0.1); border-color: rgba(59,130,246,0.5);
  color: #60a5fa;
}
.av-flag-chip.common.active {
  background: linear-gradient(135deg, rgba(59,130,246,0.2), rgba(6,182,212,0.15));
  border-color: #3b82f6; color: #93c5fd;
  box-shadow: 0 0 0 2px rgba(59,130,246,0.25);
}
.av-flag-toast {
  position: fixed; bottom: 2rem; left: 50%; transform: translateX(-50%);
  padding: 0.75rem 1.5rem; border-radius: 0.5rem;
  background: rgba(15,15,26,0.98); border: 1px solid rgba(245,158,11,0.4);
  color: #fcd34d; font-size: 0.9rem; font-weight: 500;
  box-shadow: 0 8px 24px rgba(0,0,0,0.4);
  z-index: 9999; opacity: 0; pointer-events: none; transition: opacity 0.25s ease;
}
.av-flag-toast.av-flag-toast-show {
  opacity: 1; pointer-events: auto;
}
@keyframes av-toast-in {
  from { opacity: 0; transform: translateX(-50%) translateY(10px); }
  to { opacity: 1; transform: translateX(-50%) translateY(0); }
}
@media (max-width: 768px) {
  .av-logo { font-size: 2.2rem; }
  .av-problem-grid { grid-template-columns: 1fr; }
  .av-stats { gap: 1.5rem; }
  .av-roadmap-grid { grid-template-columns: 1fr 1fr; }
  .av-flag-bar {
    flex-wrap: nowrap; padding: 0.75rem 1rem;
    margin-left: -0.5rem; margin-right: -0.5rem; max-width: none;
  }
  .av-flag-label { flex-shrink: 0; }
  .av-flag-chips {
    flex-wrap: nowrap; flex-shrink: 0; gap: 0.5rem;
    overflow-x: auto; overflow-y: hidden; -webkit-overflow-scrolling: touch;
    flex: 1; min-width: 0; padding-bottom: 0.25rem;
  }
  .av-flag-chips::-webkit-scrollbar { height: var(--av-scrollbar-width); }
  .av-flag-chips::-webkit-scrollbar-track { background: var(--av-scrollbar-track); border-radius: 4px; }
  .av-flag-chips::-webkit-scrollbar-thumb {
    background: linear-gradient(90deg, rgba(34,211,238,0.5) 0%, rgba(167,139,250,0.45) 100%);
    border-radius: 4px; border: 1px solid rgba(34,211,238,0.18);
  }
  .av-flag-chips::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(90deg, rgba(34,211,238,0.7) 0%, rgba(236,72,153,0.4) 100%);
  }
  .av-flag-chip { flex-shrink: 0; }
}
.av-hero-demo {
  display: flex; align-items: center; justify-content: center; gap: 2rem;
  margin: 1.5rem 0; padding: 1.25rem; flex-wrap: wrap;
  background: rgba(0,0,0,0.25); border: 1px solid rgba(255,255,255,0.08);
  border-radius: 1rem; max-width: 720px; margin-left: auto; margin-right: auto;
}
.av-hero-demo-svg {
  width: 240px; height: 140px;
}
.av-hero-demo-svg .node { fill: rgba(139,92,246,0.3); stroke: #8b5cf6; stroke-width: 2; }
.av-hero-demo-svg .arrow { stroke: #94a3b8; stroke-width: 2; fill: none; }
.av-hero-demo-svg .ptr { fill: #10b981; animation: av-demo-pulse 1.5s ease-in-out infinite; }
.av-hero-demo-svg .node { animation: av-demo-glow 2s ease-in-out infinite; }
@keyframes av-demo-pulse { 0%,100% { opacity: 1; } 50% { opacity: 0.5; } }
@keyframes av-demo-glow { 0%,100% { opacity: 0.8; } 50% { opacity: 1; } }
.av-hero-demo-cta {
  display: flex; flex-direction: column; gap: 0.5rem; align-items: flex-start;
}
.av-hero-demo-cta strong { color: #10b981; font-size: 0.9rem; }
.av-hero-demo-cta a {
  display: inline-flex; align-items: center; gap: 0.4rem;
  padding: 0.5rem 1rem; background: rgba(16,185,129,0.15); border: 1px solid rgba(16,185,129,0.4);
  color: #10b981; text-decoration: none; font-weight: 600; font-size: 0.85rem; border-radius: 0.5rem;
  transition: all 0.2s;
}
.av-hero-demo-cta a:hover { background: rgba(16,185,129,0.25); transform: translateY(-1px); }
.av-start-here {
  display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; justify-content: center;
  margin: 1.25rem 0; padding: 1.25rem 1.5rem; background: rgba(16,185,129,0.08);
  border: 1px solid rgba(16,185,129,0.25); border-radius: 0.75rem; max-width: 720px; margin-left: auto; margin-right: auto;
}
.av-start-here-badge { font-size: 0.65rem; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; color: #10b981; }
.av-start-here a {
  display: inline-flex; align-items: center; gap: 0.5rem; padding: 0.65rem 1.35rem; font-size: 1rem;
  background: linear-gradient(135deg,#10b981,#059669); color: white; text-decoration: none; font-weight: 600;
  border-radius: 0.5rem; font-size: 0.95rem; transition: all 0.2s;
}
.av-start-here a:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(16,185,129,0.4); }
.av-start-here-hint { font-size: 0.8rem; color: #94a3b8; }
.av-how-it-works {
  max-width: 560px; margin: 0.75rem auto 1rem; padding: 0.75rem 1rem;
  background: rgba(99,102,241,0.06); border: 1px solid rgba(99,102,241,0.15);
  border-radius: 0.5rem; font-size: 0.88rem; color: #94a3b8;
}
.av-how-it-works summary { cursor: pointer; font-weight: 600; color: #a5b4fc; user-select: none; }
.av-how-it-works ol { margin: 0.5rem 0 0 1.2rem; padding: 0; line-height: 1.7; }
.av-how-it-works kbd { padding: 0.1rem 0.35rem; background: rgba(255,255,255,0.08); border-radius: 0.25rem; font-size: 0.75rem; }
.av-daily-problem {
  display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
  padding: 0.75rem 1.25rem; background: rgba(99,102,241,0.08); border: 1px solid rgba(99,102,241,0.2);
  border-radius: 0.5rem; margin-bottom: 1rem; max-width: 560px; margin-left: auto; margin-right: auto;
}
.av-daily-problem-label { font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; color: #6366f1; }
.av-daily-problem a {
  display: inline-flex; align-items: center; gap: 0.4rem; color: #a5b4fc; text-decoration: none; font-weight: 600; font-size: 0.9rem;
}
.av-daily-problem a:hover { text-decoration: underline; }
.av-company-progress {
  display: flex; align-items: center; gap: 0.75rem; flex-wrap: wrap; margin-bottom: 1rem; max-width: 560px; margin-left: auto; margin-right: auto;
  position: relative; overflow: visible;
}
.av-company-progress select {
  background: #1e293b; border: 1px solid rgba(255,255,255,0.2); color: #e2e8f0;
  padding: 0.4rem 0.75rem; border-radius: 0.4rem; font-size: 0.85rem; cursor: pointer;
  position: relative; z-index: 10; min-width: 180px;
  color-scheme: dark; appearance: auto;
}
.av-company-progress select option {
  background: #1e293b; color: #e2e8f0;
}
.av-company-progress .av-cp-bar {
  flex: 1; min-width: 120px; height: 8px; background: rgba(255,255,255,0.08); border-radius: 4px; overflow: hidden;
}
.av-company-progress .av-cp-fill {
  height: 100%; background: linear-gradient(90deg,#10b981,#06b6d4); border-radius: 4px; transition: width 0.3s;
}
.av-company-progress .av-cp-text { font-size: 0.8rem; color: #94a3b8; }

.av-changelog-banner {
  position: relative;
  max-width: 720px;
  margin: 0 auto 1.25rem;
  padding: 0.75rem 2.25rem 0.75rem 1rem;
  font-size: 0.85rem;
  line-height: 1.5;
  color: #cbd5e1;
  background: rgba(99,102,241,0.12);
  border: 1px solid rgba(99,102,241,0.35);
  border-radius: 0.65rem;
}
.av-changelog-banner strong { color: #a5b4fc; }
.av-changelog-dismiss {
  position: absolute;
  top: 0.35rem;
  right: 0.45rem;
  border: none;
  background: transparent;
  color: #94a3b8;
  font-size: 1.25rem;
  line-height: 1;
  cursor: pointer;
  padding: 0.2rem 0.45rem;
  border-radius: 0.25rem;
}
.av-changelog-dismiss:hover { color: #e2e8f0; background: rgba(255,255,255,0.06); }

.av-review-due-banner {
  display: none;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.75rem 1rem;
  max-width: 720px;
  margin: 0 auto 1.25rem;
  padding: 0.65rem 1rem;
  font-size: 0.85rem;
  color: #fde68a;
  background: rgba(245,158,11,0.1);
  border: 1px solid rgba(245,158,11,0.35);
  border-radius: 0.65rem;
}
.av-review-due-banner a {
  color: #fcd34d;
  font-weight: 600;
  text-decoration: none;
}
.av-review-due-banner a:hover { text-decoration: underline; }

.av-onboarding-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 10050;
  background: rgba(15,15,26,0.82);
  align-items: center;
  justify-content: center;
  padding: 1rem;
}
.av-onboarding-card {
  max-width: 420px;
  padding: 1.5rem 1.35rem;
  background: #151528;
  border: 1px solid rgba(99,102,241,0.35);
  border-radius: 0.85rem;
  box-shadow: 0 20px 50px rgba(0,0,0,0.45);
}
.av-onboarding-card h2 {
  font-size: 1.25rem;
  color: #e2e8f0;
  margin-bottom: 0.75rem;
}
.av-onboarding-card p {
  font-size: 0.88rem;
  color: #94a3b8;
  line-height: 1.55;
  margin: 0.45rem 0;
}
.av-onboarding-card button {
  margin-top: 1rem;
  width: 100%;
  padding: 0.55rem 1rem;
  border: none;
  border-radius: 0.5rem;
  background: linear-gradient(135deg, #6366f1, #8b5cf6);
  color: white;
  font-weight: 600;
  cursor: pointer;
}

.av-lc-freq {
  font-size: 0.62rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: #67e8f9;
  padding: 0.12rem 0.4rem;
  border-radius: 0.25rem;
  background: rgba(6,182,212,0.12);
  border: 1px solid rgba(6,182,212,0.25);
  white-space: nowrap;
}

/* ── Problem search ─────────────────────────────────── */
.av-search-wrap {
  position: relative;
  max-width: 480px;
  margin: 0 auto 1.25rem;
}
.av-search-wrap input {
  width: 100%;
  padding: 0.65rem 1rem 0.65rem 2.4rem;
  border-radius: 0.6rem;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(255,255,255,0.05);
  color: #e2e8f0;
  font-size: 0.95rem;
  font-family: 'Segoe UI', system-ui, sans-serif;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.av-search-wrap input::placeholder { color: #64748b; }
.av-search-wrap input:focus {
  border-color: #6366f1;
  box-shadow: 0 0 0 3px rgba(99,102,241,0.15);
}
.av-search-icon {
  position: absolute;
  left: 0.8rem;
  top: 50%;
  transform: translateY(-50%);
  color: #64748b;
  font-size: 0.85rem;
  pointer-events: none;
}
.av-search-results {
  position: absolute;
  top: calc(100% + 4px);
  left: 0; right: 0;
  max-height: 340px;
  overflow-y: auto;
  background: rgba(15,15,26,0.98);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 0.6rem;
  z-index: 200;
  box-shadow: 0 8px 32px rgba(0,0,0,0.6);
  display: none;
}
.av-search-results.visible { display: block; }
.av-search-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 1rem;
  text-decoration: none;
  color: #e2e8f0;
  transition: background 0.15s;
  border-bottom: 1px solid rgba(255,255,255,0.05);
}
.av-search-item:last-child { border-bottom: none; }
.av-search-item:hover, .av-search-item.active {
  background: rgba(99,102,241,0.12);
}
.av-search-item-lc {
  font-size: 0.72rem;
  color: #64748b;
  min-width: 2.6rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
.av-search-item-name { font-weight: 600; font-size: 0.9rem; flex: 1; }
.av-search-item-diff {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
}
.av-search-item-diff.easy   { color: #10b981; background: rgba(16,185,129,0.12); }
.av-search-item-diff.medium { color: #f59e0b; background: rgba(245,158,11,0.12); }
.av-search-item-diff.hard   { color: #ef4444; background: rgba(239,68,68,0.12); }
.av-search-item-section {
  font-size: 0.72rem;
  color: #64748b;
  white-space: nowrap;
}
.av-search-empty {
  padding: 1rem;
  text-align: center;
  color: #64748b;
  font-size: 0.85rem;
}
.av-search-results::-webkit-scrollbar { width: 4px; }
.av-search-results::-webkit-scrollbar-track { background: transparent; }
.av-search-results::-webkit-scrollbar-thumb { background: rgba(148,163,184,0.3); border-radius: 2px; }

/* System design track (sub-area inside AlgoVision) */
.av-track-switch {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin: 0.75rem auto 1rem;
  flex-wrap: wrap;
}
.av-track-btn {
  padding: 0.45rem 1.15rem;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.04);
  color: #94a3b8;
  font-weight: 600;
  cursor: pointer;
  font-size: 0.88rem;
  transition: all 0.2s;
}
.av-track-btn:hover {
  border-color: rgba(6, 182, 212, 0.35);
  color: #e2e8f0;
}
.av-track-btn.active {
  background: linear-gradient(135deg, #06b6d4, #6366f1);
  color: #fff;
  border-color: transparent;
}
.av-wrapper[data-av-track="sd"] .av-dsa-only {
  display: none !important;
}
.av-wrapper[data-av-track="sd"] #sd-hub {
  display: block !important;
}
.av-wrapper[data-av-track="sd"] .av-hero-tag-dsa {
  display: none !important;
}
.av-wrapper[data-av-track="sd"] .av-hero-tag-sd {
  display: block !important;
}
.av-hero-tag-sd {
  display: none;
  font-size: 1.15rem;
  color: #94a3b8;
  margin-bottom: 0.5rem;
  font-weight: 400;
}
/* RoboVision tab (top-level) — hub card styles */
.rv-hub-intro {
  text-align: center;
  color: #94a3b8;
  font-size: 0.95rem;
  line-height: 1.65;
  max-width: 720px;
  margin: 0 auto 1.5rem;
}
.rv-hub-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(245, 158, 11, 0.2);
  border-radius: 0.75rem;
  padding: 1.15rem;
  text-decoration: none;
  color: inherit;
  display: block;
  transition: all 0.2s ease;
  max-width: 420px;
  margin: 0 auto;
}
.rv-hub-card:hover {
  border-color: rgba(245, 158, 11, 0.5);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(245, 158, 11, 0.1);
}
.rv-hub-card h4 {
  font-size: 1rem;
  margin: 0 0 0.4rem;
  color: #fbbf24;
  font-weight: 700;
}
.rv-hub-card p {
  font-size: 0.82rem;
  color: #94a3b8;
  margin: 0;
  line-height: 1.45;
}
.rv-hub-meta {
  font-size: 0.72rem;
  color: #64748b;
  margin-top: 0.55rem;
}
#sd-hub {
  display: none;
  max-width: 1200px;
  margin: 0 auto 2.5rem;
  padding: 0 0.25rem;
}
.sd-hub-intro {
  text-align: center;
  color: #94a3b8;
  font-size: 0.95rem;
  line-height: 1.65;
  max-width: 720px;
  margin: 0 auto 1.5rem;
}
.sd-hub-stats {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 1.75rem;
  flex-wrap: wrap;
}
.sd-hub-stats .av-stat-num {
  color: #06b6d4;
}
.sd-hub-section {
  margin-bottom: 2.25rem;
  scroll-margin-top: 0.5rem;
}
.sd-hub-head {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  padding-bottom: 0.65rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.sd-hub-head i {
  font-size: 1.2rem;
  color: #06b6d4;
}
.sd-hub-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: #e2e8f0;
}
.sd-hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
}
.sd-hub-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 0.75rem;
  padding: 1.15rem;
  text-decoration: none;
  color: inherit;
  display: block;
  transition: all 0.2s ease;
}
.sd-hub-card:hover {
  border-color: rgba(6, 182, 212, 0.45);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(6, 182, 212, 0.08);
}
.sd-hub-card h4 {
  font-size: 1rem;
  margin: 0 0 0.4rem;
  color: #22d3ee;
  font-weight: 700;
}
.sd-hub-card p {
  font-size: 0.82rem;
  color: #94a3b8;
  margin: 0;
  line-height: 1.45;
}
.sd-hub-meta {
  font-size: 0.72rem;
  color: #64748b;
  margin-top: 0.55rem;
}

/* ── Last-reviewed badge (injected by hub JS) ───── */
.av-last-review {
  position: absolute;
  bottom: 0.45rem;
  right: 0.5rem;
  font-size: 0.6rem;
  font-weight: 700;
  color: #94a3b8;
  opacity: 0.7;
}

/* ── Company frequency badge ───────────────────── */
.av-freq-badge {
  position: absolute;
  top: 0.45rem;
  right: 2.5rem;
  font-size: 0.58rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: #fbbf24;
  padding: 0.1rem 0.35rem;
  border-radius: 0.2rem;
  background: rgba(251,191,36,0.1);
  border: 1px solid rgba(251,191,36,0.2);
}

/* ── Section completion bar ────────────────────── */
.av-section-progress {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
}
.av-section-progress-bar {
  width: 60px;
  height: 5px;
  background: rgba(255,255,255,0.06);
  border-radius: 3px;
  overflow: hidden;
}
.av-section-progress-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.5s;
}
.av-section-progress-text {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--av-dim);
  min-width: 2.5rem;
  text-align: right;
}

/* ── Streak badge in daily problem ─────────────── */
.av-streak-badge {
  margin-left: auto;
  padding: 0.4rem 0.85rem;
  border-radius: 0.5rem;
  background: rgba(251,191,36,0.1);
  border: 1px solid rgba(251,191,36,0.25);
  font-size: 0.82rem;
  font-weight: 700;
  color: #fbbf24;
  white-space: nowrap;
}