/* ─── AI EXPERT LAB — Course Template ─────────────────────────────────────── */
:root {
  color-scheme: light;
  --bg: #f0f5fb;
  --panel: #ffffff;
  --ink: #111827;
  --muted: #5f6673;
  --line: #d5e0eb;
  --accent: #ec4899;
  --accent-dark: #be185d;
  --accent-alpha: rgba(236,72,153,0.12);
  --shadow-sm: 0 1px 3px rgba(17, 24, 39, 0.05), 0 4px 12px rgba(17, 24, 39, 0.04);
  --shadow-md: 0 2px 4px rgba(17, 24, 39, 0.04), 0 10px 22px rgba(17, 24, 39, 0.07), 0 28px 56px rgba(17, 24, 39, 0.05);
  --shadow-hover: 0 2px 4px rgba(17, 24, 39, 0.04), 0 12px 28px rgba(17, 24, 39, 0.1), 0 40px 80px rgba(17, 24, 39, 0.08), 0 0 0 1px var(--accent-alpha);
  --radius: 10px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
}

main {
  background: linear-gradient(180deg, #eef3f8 0%, #e7edf4 50%, #dde5ec 100%);
  padding-bottom: 40px;
}

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

code {
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #e7f6fb;
  padding: 0.15rem 0.34rem;
  color: var(--accent-dark);
  font-size: 0.91em;
}

/* ─── HERO ──────────────────────────────────────────────────────────────────── */
.hero {
  min-height: 92vh;
  padding: 22px clamp(18px, 4vw, 56px) 72px;
  background: #080e16;
  color: #fff;
  position: relative;
  overflow: hidden;
}

.hero-bg-video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(150deg, rgba(8, 14, 22, 0.75) 0%, rgba(8, 14, 22, 0.55) 100%);
  z-index: 1;
}

.hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0;
  height: 180px;
  background: linear-gradient(to top, #eef3f8, transparent);
  z-index: 2;
  pointer-events: none;
}

/* ─── TOPBAR ─────────────────────────────────────────────────────────────────── */
.topbar {
  position: relative;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  max-width: 1280px;
  margin: 0 auto;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 10px;
  background: linear-gradient(135deg, #0d1f2f, #0f6ea8);
  border: 2px solid #20d3e6;
  color: #fff;
  font-weight: 900;
  font-size: 0.9rem;
  letter-spacing: -0.5px;
}

.brand strong, .brand small { display: block; }
.brand strong { font-size: 1rem; }
.brand small { color: rgba(255, 255, 255, 0.58); font-size: 0.76rem; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 5px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(20px);
}

.nav-links a {
  padding: 9px 14px;
  border-radius: 7px;
  color: rgba(255, 255, 255, 0.76);
  font-size: 0.91rem;
  font-weight: 700;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}

.nav-links a:hover { background: rgba(19, 184, 207, 0.16); color: #fff; }

.nav-links .nav-cta {
  background: var(--accent);
  color: #05141b;
  font-weight: 800;
}

.nav-links .nav-cta:hover { background: #fff; color: #0b2238; }

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.07);
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  margin: 4px auto;
  background: #fff;
  border-radius: 2px;
}

/* ─── HERO CONTENT ───────────────────────────────────────────────────────────── */
.hero-grid {
  position: relative;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  max-width: 1280px;
  min-height: calc(92vh - 80px);
  margin: 0 auto;
  padding-top: 60px;
}

.hero-copy {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.hero-kurs {
  margin: 0 0 8px;
  font-size: clamp(3.2rem, 9vw, 7.5rem);
  font-weight: 900;
  line-height: 0.95;
  letter-spacing: -0.03em;
  color: #fff;
  text-shadow: 0 0 80px rgba(19, 184, 207, 0.35);
}

.hero-copy h1 {
  font-size: clamp(1.3rem, 3vw, 2.6rem);
  font-weight: 600;
  margin: 0 0 32px;
  color: rgba(255, 255, 255, 0.8);
  max-width: 680px;
  line-height: 1.35;
}

.hero-course-stats {
  display: flex;
  align-items: center;
  margin: 0 0 32px;
  padding: 16px 28px;
  border: 1px solid rgba(32, 211, 230, 0.28);
  border-radius: 12px;
  background: rgba(32, 211, 230, 0.07);
  backdrop-filter: blur(14px);
  box-shadow: 0 0 48px rgba(19, 184, 207, 0.08), inset 0 1px 0 rgba(255, 255, 255, 0.07);
}

.hcs-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  padding: 0 24px;
}

.hcs-item strong {
  font-size: 1.6rem;
  font-weight: 900;
  color: #20d3e6;
  line-height: 1;
}

.hcs-item span {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: rgba(255, 255, 255, 0.5);
}

.hcs-sep {
  width: 1px;
  height: 40px;
  background: rgba(255, 255, 255, 0.12);
  flex-shrink: 0;
}

.teacher {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  margin: 0 0 28px;
  padding: 10px 16px;
  border: 1px solid rgba(255, 255, 255, 0.13);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(8px);
}

.teacher span { color: rgba(255, 255, 255, 0.52); font-size: 0.88rem; }
.teacher strong { font-size: 1rem; }

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

/* ─── BUTTONS ────────────────────────────────────────────────────────────────── */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 0 22px;
  border-radius: 10px;
  font-weight: 800;
  font-size: 0.94rem;
  border: 0;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.button.primary {
  background: var(--accent);
  color: #04131a;
  box-shadow: 0 4px 16px rgba(19, 184, 207, 0.38);
}

.button.primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(19, 184, 207, 0.5);
}

.button.secondary {
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #fff;
  background: rgba(255, 255, 255, 0.06);
}

.button.secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  transform: translateY(-2px);
}

/* ─── QUICK NAV ──────────────────────────────────────────────────────────────── */
.quick-nav {
  position: fixed;
  z-index: 20;
  right: 20px;
  top: 50%;
  display: grid;
  gap: 8px;
  transform: translateY(-50%);
}

.quick-nav a {
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 8px;
  align-items: center;
  min-width: 130px;
  min-height: 44px;
  border: 1px solid rgba(17, 24, 39, 0.08);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 4px 16px rgba(17, 24, 39, 0.1), 0 1px 3px rgba(17, 24, 39, 0.05);
  backdrop-filter: blur(16px);
  padding: 6px 10px 6px 6px;
  color: #243044;
  font-size: 0.82rem;
  font-weight: 800;
  transition: transform 0.18s ease, background 0.18s, border-color 0.18s, color 0.18s;
}

.quick-nav a:hover {
  background: #111827;
  border-color: #111827;
  color: #fff;
  transform: translateX(-4px);
}

.quick-nav span {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 7px;
  background: var(--accent-alpha);
  color: var(--accent-dark);
  font-size: 0.68rem;
  font-weight: 900;
  transition: background 0.18s, color 0.18s;
}

.quick-nav a:hover span { background: var(--accent); color: #0b2238; }

/* ─── SECTIONS ───────────────────────────────────────────────────────────────── */
.section {
  width: min(1280px, calc(100% - 40px));
  margin: 0 auto;
  padding: 88px 0 0;
}

.section-heading {
  max-width: 780px;
  margin-bottom: 36px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--accent-dark);
  font-size: 0.75rem;
  font-weight: 900;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

h1, h2, h3 { margin: 0; line-height: 1.05; }

.section-heading h2 {
  font-size: clamp(2rem, 5vw, 3.8rem);
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.section-heading p:not(.eyebrow) {
  margin-top: 14px;
  color: var(--muted);
  font-size: 1.06rem;
  line-height: 1.8;
}

/* ─── TOPIC FILTER ───────────────────────────────────────────────────────────── */
.topic-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}

.filter {
  min-height: 40px;
  border: 1.5px solid var(--line);
  border-radius: 999px;
  background: #fff;
  padding: 0 18px;
  color: var(--muted);
  font: inherit;
  font-weight: 800;
  font-size: 0.88rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s, transform 0.15s;
}

.filter:hover { border-color: var(--accent); color: var(--accent-dark); transform: translateY(-1px); }

.filter.active {
  border-color: transparent;
  background: var(--ink);
  color: #fff;
  box-shadow: 0 4px 12px rgba(17, 24, 39, 0.18);
}

/* ─── TOPICS LAYOUT ──────────────────────────────────────────────────────────── */
.topics-layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.topic-index {
  position: sticky;
  top: 16px;
  display: grid;
  gap: 5px;
  max-height: calc(100vh - 32px);
  overflow: auto;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.9);
  box-shadow: var(--shadow-sm);
}

.index-link {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 10px;
  align-items: center;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--muted);
  font-size: 0.84rem;
  font-weight: 700;
  transition: background 0.15s, color 0.15s;
}

.index-link span {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--accent-alpha);
  color: var(--accent-dark);
  font-weight: 900;
  font-size: 0.76rem;
  transition: background 0.15s, color 0.15s;
}

.index-link:hover { background: #eaf8fb; color: var(--ink); }

/* ─── TOPIC CARDS ────────────────────────────────────────────────────────────── */
.topic-list { display: grid; gap: 20px; }

.topic-card {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fff;
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: transform 0.32s cubic-bezier(0.34, 1.56, 0.64, 1),
              box-shadow 0.32s ease,
              border-color 0.32s ease;
}

.topic-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover), 0 0 60px rgba(19, 184, 207, 0.07);
  border-color: rgba(19, 184, 207, 0.24);
}

.topic-media {
  min-height: 240px;
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #0b1827 0%, #0f2e4a 100%);
}

.topic-media img {
  width: 100%;
  height: 100%;
  min-height: 240px;
  object-fit: cover;
  display: block;
  transition: transform 0.5s ease;
}

.topic-card:hover .topic-media img { transform: scale(1.03); }

.image-fallback {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  text-align: center;
  background: linear-gradient(135deg, #0b1827, #0f3352);
  color: #fff;
}

.image-fallback[hidden] { display: none; }

.image-fallback strong {
  display: block;
  font-size: 5rem;
  line-height: 1;
  color: rgba(32, 211, 230, 0.35);
}

.image-fallback span {
  display: block;
  margin-top: 10px;
  color: rgba(255, 255, 255, 0.55);
  font-weight: 700;
}

.topic-body { padding: clamp(20px, 4vw, 36px); }

.topic-kicker {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.topic-number {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  border-radius: 999px;
  padding: 0 12px;
  font-size: 0.75rem;
  font-weight: 900;
  background: var(--ink);
  color: #fff;
}

.category {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  border-radius: 999px;
  padding: 0 12px;
  font-size: 0.75rem;
  font-weight: 900;
  background: var(--accent-alpha);
  color: var(--accent-dark);
}

.topic-card h3 {
  font-size: clamp(1.25rem, 2.6vw, 2rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin-bottom: 10px;
  line-height: 1.2;
}

.topic-card p {
  color: var(--muted);
  line-height: 1.75;
  margin: 0 0 14px;
}

.used-tools {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.tool-pill {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 5px 12px;
  background: #fff;
  color: #374151;
  font-size: 0.8rem;
  font-weight: 700;
  transition: border-color 0.15s, background 0.15s;
}

.tool-pill:hover { border-color: var(--accent); background: var(--accent-alpha); }

.topic-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

/* ─── MATERIAL LINKS ─────────────────────────────────────────────────────────── */
.material-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 44px;
  border-radius: 10px;
  padding: 0 16px;
  font-weight: 800;
  font-size: 0.87rem;
  background: var(--accent-alpha);
  color: var(--accent-dark);
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.material-link:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(19, 184, 207, 0.2);
}

.material-link.word { background: #eff6ff; color: #1d4ed8; }
.material-link.word:hover { box-shadow: 0 4px 12px rgba(29, 78, 216, 0.18); }

.material-link.app { background: #f1f5f9; color: #334155; }

.material-link.yt {
  background: #e11d1d;
  color: #fff;
  box-shadow: 0 4px 12px rgba(220, 38, 38, 0.22);
}

.material-link.yt:hover {
  background: #cc1515;
  box-shadow: 0 6px 18px rgba(220, 38, 38, 0.38);
  transform: translateY(-2px);
}

.material-link.yt--soon {
  background: #f1f5f9;
  color: #94a3b8;
  cursor: default;
  pointer-events: none;
  box-shadow: none;
}

/* ─── DEFINITIONS ────────────────────────────────────────────────────────────── */
.definition-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.definition-card {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow-sm);
  padding: 22px;
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.definition-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: rgba(19, 184, 207, 0.22);
}

.definition-card h3 { font-size: 1.05rem; font-weight: 800; margin-bottom: 8px; }
.definition-card p { color: var(--muted); line-height: 1.65; margin: 0; font-size: 0.9rem; }

.tag-row { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 14px; }

.tag {
  display: inline-flex;
  align-items: center;
  min-height: 26px;
  padding: 0 10px;
  border-radius: 999px;
  background: var(--accent-alpha);
  color: var(--accent-dark);
  font-size: 0.75rem;
  font-weight: 800;
}

/* ─── TOOLS SECTION ──────────────────────────────────────────────────────────── */
.tools-section {
  width: 100%;
  max-width: none;
  padding: 88px max(20px, calc((100vw - 1280px) / 2)) 0;
  background: linear-gradient(180deg, transparent 0, rgba(255, 255, 255, 0.3) 8%, rgba(255, 255, 255, 0.3) 92%, transparent 100%);
}

.tool-controls { margin-bottom: 20px; }

.search {
  display: grid;
  gap: 8px;
  max-width: 480px;
  color: var(--muted);
  font-weight: 700;
  font-size: 0.9rem;
}

.search input {
  width: 100%;
  min-height: 50px;
  border: 1.5px solid var(--line);
  border-radius: 10px;
  padding: 0 16px;
  color: var(--ink);
  font: inherit;
  outline: 0;
  background: #fff;
  box-shadow: var(--shadow-sm);
}

.search input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-alpha);
}

.tool-grid { display: grid; gap: 10px; }

.tool-card {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr) minmax(240px, auto);
  gap: 16px;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.96);
  padding: 16px;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.2s, transform 0.2s, box-shadow 0.2s;
}

.tool-card:hover {
  border-color: rgba(19, 184, 207, 0.28);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.tool-id {
  display: grid;
  grid-template-columns: 28px 50px;
  gap: 10px;
  align-items: center;
}

.tool-number { color: #94a3b8; font-size: 0.79rem; font-weight: 900; text-align: right; }

.tool-icon {
  display: grid;
  place-items: center;
  width: 50px;
  height: 50px;
  border-radius: 10px;
  background: #f8fafc;
  border: 1px solid var(--line);
  overflow: hidden;
}

.tool-icon img { width: 28px; height: 28px; object-fit: contain; }

.tool-icon span {
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #0d1927, var(--accent-dark));
  color: #fff;
  font-size: 0.88rem;
  font-weight: 900;
}

.tool-main h3 { margin: 0 0 5px; font-size: 1rem; font-weight: 800; }
.tool-main p { margin: 0; color: var(--muted); line-height: 1.5; font-size: 0.9rem; }

.tool-meta { display: flex; align-items: center; justify-content: flex-end; gap: 12px; }

.tool-modules { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 6px; }

.tool-card .tool-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  border-radius: 8px;
  background: var(--accent-dark);
  padding: 0 14px;
  color: #fff;
  font-weight: 900;
  font-size: 0.85rem;
  white-space: nowrap;
  transition: background 0.15s, transform 0.15s;
}

.tool-card .tool-link:hover { background: var(--accent); transform: translateY(-1px); }

/* ─── QUIZ ───────────────────────────────────────────────────────────────────── */
.quiz-section { width: min(1080px, calc(100% - 40px)); }

.quiz-shell {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.quiz-toolbar, .quiz-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 24px;
  background: #f8fafc;
}

.quiz-toolbar strong { display: block; font-size: 1.5rem; color: var(--ink); }
.quiz-toolbar span { color: var(--muted); font-weight: 700; font-size: 0.9rem; }

.quiz-reset {
  border: 1.5px solid var(--line);
  background: #fff;
  color: var(--ink);
  min-height: 40px;
  padding: 0 16px;
  border-radius: 8px;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: border-color 0.15s;
}

.quiz-reset:hover { border-color: var(--accent); }

.quiz-list { display: grid; }

.quiz-card {
  padding: 24px;
  border-top: 1px solid var(--line);
  transition: background 0.2s;
}

.quiz-question {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 14px;
  align-items: start;
  margin-bottom: 18px;
}

.quiz-question span {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 10px;
  background: var(--ink);
  color: #fff;
  font-weight: 900;
  font-size: 0.87rem;
}

.quiz-question h3 { font-size: clamp(1rem, 2vw, 1.26rem); line-height: 1.4; font-weight: 700; }

.quiz-options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.quiz-option {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 10px;
  align-items: center;
  min-height: 60px;
  border: 1.5px solid var(--line);
  border-radius: 10px;
  background: #fff;
  padding: 10px 12px;
  color: #374151;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, transform 0.15s;
}

.quiz-option:hover { border-color: var(--accent); background: #eaf8fb; transform: translateY(-1px); }
.quiz-option input { position: absolute; opacity: 0; pointer-events: none; }

.option-letter {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  background: var(--accent-alpha);
  color: var(--accent-dark);
  font-weight: 900;
  font-size: 0.9rem;
}

.quiz-option:has(input:checked) { border-color: var(--accent); background: #eaf8fb; }

.quiz-feedback { min-height: 22px; margin: 12px 0 0; color: var(--muted); font-weight: 700; font-size: 0.9rem; }

.quiz-card.correct { background: linear-gradient(90deg, rgba(236, 253, 245, 0.92), rgba(255, 255, 255, 0.96)); }
.quiz-card.correct .quiz-feedback { color: #15803d; }
.quiz-card.wrong { background: linear-gradient(90deg, rgba(255, 241, 242, 0.92), rgba(255, 255, 255, 0.96)); }
.quiz-card.wrong .quiz-feedback, .quiz-card.missing .quiz-feedback { color: #be123c; }

.quiz-submit { border: 0; }

.quiz-result { display: flex; flex-direction: column; gap: 3px; color: var(--muted); text-align: right; }
.quiz-result strong { color: var(--ink); font-size: 1.4rem; }

/* ─── BLIK DONATION SECTION ──────────────────────────────────────────────────── */
.blik-section { padding-bottom: 88px; }

.blik-inner {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: 48px;
  align-items: center;
  padding: 56px;
  background: linear-gradient(135deg, #0b1827 0%, #0d2540 60%, #0a1d36 100%);
  border-radius: 20px;
  color: #fff;
  position: relative;
  overflow: hidden;
  box-shadow: 0 24px 80px rgba(8, 14, 22, 0.32), 0 0 0 1px rgba(255, 255, 255, 0.04);
}

.blik-inner::before {
  content: '';
  position: absolute;
  width: 480px;
  height: 480px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0, 102, 204, 0.22), transparent 68%);
  right: -80px;
  top: -120px;
  pointer-events: none;
}

.blik-inner::after {
  content: '';
  position: absolute;
  width: 280px;
  height: 280px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(19, 184, 207, 0.12), transparent 65%);
  left: -50px;
  bottom: -70px;
  pointer-events: none;
}

.blik-copy .eyebrow { color: #64d8e8; }

.blik-copy h2 {
  font-size: clamp(1.9rem, 4vw, 3rem);
  font-weight: 900;
  letter-spacing: -0.02em;
  color: #fff;
  margin-bottom: 16px;
}

.blik-copy > p:not(.eyebrow) {
  color: rgba(255, 255, 255, 0.65);
  font-size: 1.06rem;
  line-height: 1.78;
  max-width: 500px;
  margin: 0;
}

.blik-card {
  position: relative;
  z-index: 2;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 16px;
  padding: 36px 28px;
  text-align: center;
  backdrop-filter: blur(16px);
}

.blik-logo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 64px;
  height: 64px;
  border-radius: 14px;
  background: linear-gradient(135deg, #004db8, #0066ff);
  margin-bottom: 20px;
  box-shadow: 0 8px 24px rgba(0, 77, 184, 0.5);
}

.blik-label {
  font-size: 0.74rem;
  font-weight: 900;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.45);
  margin-bottom: 8px;
}

.blik-phone {
  font-size: 1.75rem;
  font-weight: 900;
  color: #20d3e6;
  letter-spacing: 0.05em;
  margin-bottom: 8px;
  font-variant-numeric: tabular-nums;
}

.blik-info {
  font-size: 0.84rem;
  color: rgba(255, 255, 255, 0.44);
  margin-bottom: 24px;
  line-height: 1.5;
}

.blik-copy-btn {
  width: 100%;
  min-height: 48px;
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, #0050cc, #0077e6);
  color: #fff;
  font: inherit;
  font-size: 0.94rem;
  font-weight: 800;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  box-shadow: 0 4px 16px rgba(0, 80, 204, 0.38);
}

.blik-copy-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0, 80, 204, 0.48); }

.blik-copy-btn.copied {
  background: linear-gradient(135deg, #059669, #10b981);
  box-shadow: 0 4px 16px rgba(5, 150, 105, 0.38);
}

/* ─── FOOTER ─────────────────────────────────────────────────────────────────── */
.footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
  width: min(1280px, calc(100% - 40px));
  margin: 0 auto;
  padding: 28px 0 40px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.footer strong { color: var(--ink); font-weight: 800; }
.footer a:hover { color: var(--accent-dark); }

/* ─── RESPONSIVE ─────────────────────────────────────────────────────────────── */
@media (max-width: 980px) {
  .topics-layout { grid-template-columns: 1fr; }
  .definition-grid { grid-template-columns: repeat(2, 1fr); }
  .blik-inner { grid-template-columns: 1fr; }
  .tool-card { grid-template-columns: 88px minmax(0, 1fr); }
  .tool-meta { grid-column: 2; justify-content: space-between; }
  .quiz-options { grid-template-columns: 1fr; }
  .topic-index { position: static; grid-template-columns: repeat(2, 1fr); max-height: none; }
}

@media (max-width: 760px) {
  .hero { min-height: auto; padding: 16px 18px 52px; }
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute;
    top: 60px; right: 0; left: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    border-radius: 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
  }
  .nav-links.open { display: flex; }
  .hero-grid { padding-top: 56px; }
  .hcs-item { padding: 0 14px; }
  .hcs-item strong { font-size: 1.3rem; }
  .definition-grid, .topic-index { grid-template-columns: 1fr; }
  .tool-card { grid-template-columns: 1fr; }
  .tool-id { grid-template-columns: 28px 46px; }
  .tool-meta { flex-direction: column; align-items: stretch; justify-content: flex-start; }
  .tool-modules { justify-content: flex-start; }
  .blik-inner { padding: 36px 24px; }
  .blik-card { padding: 28px 20px; }
  .blik-phone { font-size: 1.5rem; }
  .section { width: min(100% - 28px, 1280px); padding-top: 64px; }
  .quick-nav {
    top: auto; right: 10px; bottom: 10px; left: 10px;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 6px;
    transform: none;
  }
  .quick-nav a {
    grid-template-columns: 1fr;
    justify-items: center;
    min-width: 0;
    min-height: 50px;
    padding: 6px;
    font-size: 0.7rem;
  }
  .quick-nav span { width: auto; height: auto; background: transparent; font-size: 0.6rem; }
  .footer { flex-direction: column; align-items: flex-start; }
  .quiz-toolbar, .quiz-footer { flex-direction: column; align-items: stretch; }
  .quiz-result { text-align: left; }
}