:root {
  --bg: #0f1419;
  --bg2: #1a2332;
  --card: #1e293b;
  --card-hover: #243044;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --accent: #512bd4;
  --accent2: #00a4ef;
  --accent3: #7fba00;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
  --radius: 14px;
  --radius-sm: 10px;
}

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

html {
  font-size: 17px;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "IBM Plex Sans", system-ui, sans-serif;
  color: var(--text);
  background: radial-gradient(ellipse 120% 80% at 50% -20%, #2d3a5c 0%, var(--bg) 55%);
  background-attachment: fixed;
}

body.track-cyber {
  --accent: #059669;
  --accent2: #34d399;
  --accent3: #6ee7b7;
  --bg: #0a1210;
  --bg2: #12201c;
  --card: #1a2e28;
  --card-hover: #234038;
  background: radial-gradient(ellipse 120% 85% at 50% -15%, #14532d 0%, #0c1814 45%, var(--bg) 70%);
}

body.track-business {
  --accent: #d97706;
  --accent2: #fbbf24;
  --accent3: #fcd34d;
  --bg: #14100a;
  --bg2: #1f1810;
  --card: #2a2218;
  --card-hover: #3d3224;
  background: radial-gradient(ellipse 120% 85% at 50% -15%, #78350f 0%, #1c1410 45%, var(--bg) 70%);
}

body.track-math {
  --accent: #4f46e5;
  --accent2: #818cf8;
  --accent3: #a5b4fc;
  --bg: #0c0e18;
  --bg2: #12162a;
  --card: #1a2040;
  --card-hover: #252d52;
  background: radial-gradient(ellipse 120% 85% at 50% -15%, #312e81 0%, #0e1020 45%, var(--bg) 70%);
}

body.track-ai {
  --accent: #0891b2;
  --accent2: #22d3ee;
  --accent3: #67e8f9;
  --bg: #0a1014;
  --bg2: #0f1a22;
  --card: #152530;
  --card-hover: #1e3545;
  background: radial-gradient(ellipse 120% 85% at 50% -15%, #164e63 0%, #0a1218 45%, var(--bg) 70%);
}

body.player-open {
  overflow: hidden;
}

header {
  text-align: center;
  padding: 1.25rem 1rem 1rem;
  max-width: 920px;
  margin: 0 auto;
}

.track-tabs {
  display: inline-flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.35rem;
  padding: 0.25rem;
  margin-bottom: 1rem;
  border-radius: 999px;
  background: rgba(15, 23, 42, 0.55);
  border: 1px solid rgba(148, 163, 184, 0.2);
}

body.track-cyber .track-tabs {
  background: rgba(6, 24, 20, 0.65);
  border-color: rgba(52, 211, 153, 0.2);
}

body.track-business .track-tabs {
  background: rgba(28, 20, 12, 0.65);
  border-color: rgba(251, 191, 36, 0.25);
}

body.track-math .track-tabs {
  background: rgba(12, 14, 28, 0.65);
  border-color: rgba(129, 140, 248, 0.25);
}

body.track-ai .track-tabs {
  background: rgba(8, 20, 28, 0.65);
  border-color: rgba(34, 211, 238, 0.25);
}

body.track-ksiegowosc {
  --accent: #0d9488;
  --accent2: #2dd4bf;
  --accent3: #5eead4;
  --bg: #0a1211;
  --bg2: #0f1f1d;
  --card: #16302c;
  --card-hover: #1f403a;
  background: radial-gradient(ellipse 120% 85% at 50% -15%, #115e59 0%, #0a1412 45%, var(--bg) 70%);
}

body.track-podatki {
  --accent: #dc2626;
  --accent2: #f87171;
  --accent3: #fca5a5;
  --bg: #140a0a;
  --bg2: #1f1212;
  --card: #2a1818;
  --card-hover: #3d2222;
  background: radial-gradient(ellipse 120% 85% at 50% -15%, #7f1d1d 0%, #140c0c 45%, var(--bg) 70%);
}

body.track-prawo {
  --accent: #64748b;
  --accent2: #94a3b8;
  --accent3: #cbd5e1;
  --bg: #0f1114;
  --bg2: #181c22;
  --card: #222830;
  --card-hover: #2e3540;
  background: radial-gradient(ellipse 120% 85% at 50% -15%, #334155 0%, #0e1014 45%, var(--bg) 70%);
}

body.track-ksiegowosc .track-tabs {
  background: rgba(10, 24, 22, 0.65);
  border-color: rgba(45, 212, 191, 0.25);
}

body.track-podatki .track-tabs {
  background: rgba(28, 12, 12, 0.65);
  border-color: rgba(248, 113, 113, 0.25);
}

body.track-prawo .track-tabs {
  background: rgba(16, 18, 22, 0.65);
  border-color: rgba(148, 163, 184, 0.25);
}

.track-tab {
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.45rem 1rem;
  border: none;
  border-radius: 999px;
  cursor: pointer;
  color: var(--muted);
  background: transparent;
  transition: background 0.15s ease, color 0.15s ease, box-shadow 0.15s ease;
}

.track-tab:hover {
  color: var(--text);
}

.track-tab.active {
  color: #fff;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
}

.kicker {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent2);
  margin: 0 0 0.35rem;
}

header h1 {
  font-size: clamp(1.75rem, 5vw, 2.35rem);
  font-weight: 700;
  margin: 0 0 0.5rem;
  background: linear-gradient(90deg, #fff, #a5b4fc);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

header p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1rem 3rem;
}

.view {
  display: none;
}

.view.active {
  display: block;
}

.stage-block {
  margin-bottom: 2rem;
}

.stage-block h2 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--muted);
  margin: 0 0 0.75rem;
  padding-left: 0.15rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.stage-block h2 .stage-emoji {
  font-size: 1.25rem;
}

.section-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.85rem;
}

.section-card {
  font-family: inherit;
  text-align: left;
  border: 1px solid rgba(148, 163, 184, 0.15);
  cursor: pointer;
  padding: 1rem 1rem;
  border-radius: var(--radius);
  background: var(--card);
  box-shadow: var(--shadow);
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
  color: inherit;
}

.section-card:hover {
  transform: translateY(-3px);
  background: var(--card-hover);
  border-color: color-mix(in srgb, var(--accent) 55%, transparent);
}

.section-card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin: 0 0 0.4rem;
  line-height: 1.35;
}

.section-card .count {
  font-size: 0.78rem;
  color: var(--muted);
}

.list-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.back-btn {
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: var(--card);
  color: var(--text);
  cursor: pointer;
}

.back-btn:hover {
  border-color: var(--accent2);
}

.list-header h2 {
  margin: 0;
  font-size: 1.2rem;
  flex: 1;
  line-height: 1.3;
}

.video-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.video-card {
  display: grid;
  grid-template-columns: 148px 1fr;
  gap: 0.85rem;
  align-items: start;
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  background: var(--card);
  border: 1px solid rgba(148, 163, 184, 0.12);
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  width: 100%;
  color: inherit;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.video-card:hover {
  border-color: color-mix(in srgb, var(--accent) 50%, transparent);
  transform: scale(1.005);
}

.lang-badge {
  display: inline-block;
  font-family: "JetBrains Mono", monospace;
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 0.12rem 0.35rem;
  border-radius: 4px;
  vertical-align: middle;
  margin-right: 0.15rem;
  background: rgba(148, 163, 184, 0.2);
  color: var(--muted);
}

.lang-badge.lang-PL {
  background: rgba(220, 38, 38, 0.2);
  color: #fca5a5;
}

.lang-badge.lang-EN {
  background: rgba(59, 130, 246, 0.2);
  color: #93c5fd;
}

.lang-badge.lang-PLEN {
  background: rgba(168, 85, 247, 0.2);
  color: #d8b4fe;
}

.video-card.done {
  border-color: rgba(34, 197, 94, 0.45);
  opacity: 0.88;
}

.video-card img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: 8px;
  display: block;
}

.video-card .meta h3 {
  font-size: 0.98rem;
  font-weight: 600;
  margin: 0 0 0.35rem;
  line-height: 1.35;
}

.video-card .hint {
  font-size: 0.78rem;
  color: var(--muted);
  margin: 0;
  line-height: 1.45;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.subsection-label {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--accent2);
  margin: 1.1rem 0 0.35rem;
  padding-left: 0.15rem;
}

.topic-label {
  font-size: 0.8rem;
  color: var(--muted);
  margin: 0 0 0.5rem;
}

.player-overlay {
  position: fixed;
  inset: 0;
  z-index: 100;
  background: rgba(0, 0, 0, 0.82);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.player-overlay.open {
  display: flex;
}

.player-panel {
  width: min(960px, 100%);
  max-height: 95vh;
  overflow-y: auto;
  background: var(--bg2);
  border: 1px solid rgba(148, 163, 184, 0.2);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: var(--shadow);
}

.player-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  align-items: center;
}

.player-toolbar h3 {
  margin: 0;
  flex: 1;
  font-size: 1.05rem;
  min-width: 180px;
  line-height: 1.35;
}

.toolbar-btn {
  font-family: inherit;
  font-weight: 600;
  font-size: 0.85rem;
  padding: 0.45rem 0.85rem;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  background: var(--accent);
  color: #fff;
}

.toolbar-btn.secondary {
  background: rgba(148, 163, 184, 0.2);
  color: var(--text);
}

.toolbar-btn.success {
  background: #15803d;
}

.player-wrap {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  border-radius: 10px;
  overflow: hidden;
  background: #000;
}

.player-wrap iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.player-hint {
  margin: 0.85rem 0 0;
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.5;
}

.footer-note {
  text-align: center;
  font-size: 0.72rem;
  color: var(--muted);
  padding: 1rem 1.5rem 1.5rem;
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.5;
}

.footer-note code {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.68rem;
  background: rgba(148, 163, 184, 0.12);
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
}

@media (max-width: 520px) {
  .video-card {
    grid-template-columns: 1fr;
  }

  .video-card img {
    max-height: 180px;
  }
}