:root {
  color-scheme: light;
  --bg: #f7f9ff;
  --bg-soft: #eef5ff;
  --surface: #ffffff;
  --surface-2: #f1f5ff;
  --text: #0f172a;
  --muted: #64748b;
  --line: #dbe5f4;
  --primary: #2563eb;
  --primary-2: #5b3ff0;
  --accent: #14b8a6;
  --danger: #dc2626;
  --success: #059669;
  --warning: #b45309;
  --shadow: 0 22px 70px rgba(15, 23, 42, 0.10);
  --shadow-soft: 0 12px 30px rgba(37, 99, 235, 0.10);
  --radius: 20px;
  --radius-sm: 14px;
  --font: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #07111f;
  --bg-soft: #0c182c;
  --surface: #101c31;
  --surface-2: #17233a;
  --text: #f8fafc;
  --muted: #9aa8bd;
  --line: #25364f;
  --primary: #60a5fa;
  --primary-2: #8b5cf6;
  --accent: #2dd4bf;
  --danger: #f87171;
  --success: #4ade80;
  --warning: #fbbf24;
  --shadow: 0 22px 70px rgba(0, 0, 0, 0.34);
  --shadow-soft: 0 12px 30px rgba(96, 165, 250, 0.12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 12% 16%, rgba(91, 63, 240, .13), transparent 32rem),
    radial-gradient(circle at 88% 10%, rgba(20, 184, 166, .14), transparent 34rem),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-soft) 52%, var(--bg) 100%);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.5;
}

button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

.skip-link {
  position: absolute;
  left: 1rem;
  top: -3rem;
  z-index: 50;
  background: var(--text);
  color: var(--bg);
  padding: .7rem .95rem;
  border-radius: 999px;
}
.skip-link:focus { top: 1rem; }

.shell-header {
  position: sticky;
  top: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 76px;
  padding: .8rem clamp(1rem, 4vw, 2.35rem);
  background: color-mix(in srgb, var(--surface) 84%, transparent);
  border-bottom: 1px solid color-mix(in srgb, var(--line) 80%, transparent);
  backdrop-filter: blur(18px) saturate(1.3);
}

.brand { display: inline-flex; align-items: center; gap: .78rem; min-width: 0; }
.brand-mark {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 16px;
  background: linear-gradient(135deg, #071a3d, #312e81);
  color: #fff;
  box-shadow: 0 16px 36px rgba(37, 99, 235, .18);
  overflow: hidden;
}
.brand-mark svg { width: 42px; height: 42px; }
.brand-copy strong, .brand-copy small { display: block; line-height: 1.05; }
.brand-copy strong { font-size: 1.1rem; letter-spacing: -.03em; }
.brand-copy strong span { color: var(--accent); }
.brand-copy small { margin-top: .22rem; color: var(--muted); font-size: .78rem; }

.top-nav { display: none; align-items: center; gap: .35rem; }
.top-nav.open {
  position: absolute;
  inset: 76px 1rem auto 1rem;
  display: grid;
  gap: .45rem;
  padding: .7rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.top-nav a, .top-nav button {
  min-height: 42px;
  padding: .65rem .88rem;
  border-radius: 999px;
  color: var(--muted);
  border: 0;
  background: transparent;
  transition: transform .18s ease, background .18s ease, color .18s ease;
}
.top-nav a.active, .top-nav a:hover, .top-nav button:hover { background: var(--surface-2); color: var(--text); }
.top-nav a#userBadge {
  color: var(--primary);
  border: 1px solid color-mix(in srgb, var(--primary) 20%, var(--line));
}
.nav-toggle { display: inline-grid; }
.icon-button {
  display: inline-grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  color: var(--text);
  box-shadow: var(--shadow-soft);
}

.app-shell { width: min(1200px, 100%); margin: 0 auto; padding: clamp(1rem, 2.5vw, 2rem); }

.hero {
  display: grid;
  min-height: calc(100svh - 100px);
  align-content: center;
  padding: clamp(1rem, 5vw, 4rem) 0;
}
.hero-grid { display: grid; gap: clamp(1.5rem, 4vw, 3rem); align-items: center; }
.hero h1 {
  max-width: 700px;
  margin: 0;
  font-size: clamp(3.25rem, 10vw, 6.8rem);
  line-height: .89;
  letter-spacing: -.075em;
}
.hero p { max-width: 700px; margin: 0; color: var(--muted); font-size: clamp(1.08rem, 2vw, 1.28rem); }
.hero .grid:first-child {
  position: relative;
  padding: clamp(1.2rem, 3vw, 2rem);
}
.hero .grid:first-child::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  border-radius: 32px;
  background: linear-gradient(135deg, rgba(255,255,255,.7), rgba(255,255,255,.22));
  border: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
  opacity: .8;
}
[data-theme="dark"] .hero .grid:first-child::before { background: linear-gradient(135deg, rgba(16,28,49,.65), rgba(16,28,49,.22)); }

.section { padding: clamp(1.6rem, 3vw, 3rem) 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 1rem; margin-bottom: 1rem; }
h1, h2, h3 { letter-spacing: -.035em; line-height: 1.05; }
h1 { font-size: clamp(2.2rem, 6vw, 4.2rem); margin: 0 0 .8rem; }
h2 { font-size: clamp(1.6rem, 4vw, 2.4rem); margin: 0 0 .55rem; }
h3 { margin: 0 0 .45rem; }
.eyebrow { display: inline-block; color: var(--primary-2); font-size: .78rem; font-weight: 900; letter-spacing: .12em; text-transform: uppercase; }
.muted { color: var(--muted); }
.small { font-size: .92rem; }

.grid { display: grid; gap: 1rem; }
.two, .three { grid-template-columns: 1fr; }
.stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: .85rem; }
.card, .panel, .mode-card, .stat-card, .topic-card, .empty {
  border: 1px solid color-mix(in srgb, var(--line) 90%, transparent);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--surface) 94%, transparent);
  box-shadow: var(--shadow-soft);
}
.card, .panel, .mode-card, .empty { padding: clamp(1rem, 2.5vw, 1.35rem); }
.panel { box-shadow: var(--shadow); }
.stat-card {
  padding: 1.2rem;
  min-height: 110px;
  display: grid;
  align-content: center;
  background: linear-gradient(180deg, color-mix(in srgb, var(--surface) 100%, white), color-mix(in srgb, var(--surface-2) 58%, var(--surface)));
}
.stat-card strong { font-size: clamp(2rem, 5vw, 2.8rem); line-height: 1; }
.stat-card span { color: var(--muted); margin-top: .35rem; }

.topic-card { position: relative; overflow: hidden; display: grid; gap: .78rem; }
.topic-card::after {
  content: "";
  position: absolute;
  inset: auto -30px -45px auto;
  width: 140px;
  height: 140px;
  background: radial-gradient(circle, color-mix(in srgb, var(--topic-color, var(--primary)) 24%, transparent), transparent 70%);
  pointer-events: none;
}
.topic-top { display: flex; align-items: start; justify-content: space-between; gap: 1rem; }
.topic-icon {
  flex: 0 0 auto;
  width: 56px;
  height: 56px;
  border-radius: 16px;
  background: linear-gradient(135deg, var(--topic-color, var(--primary)), color-mix(in srgb, var(--topic-color, var(--primary)) 72%, #fff));
  box-shadow: 0 18px 36px color-mix(in srgb, var(--topic-color, var(--primary)) 22%, transparent);
}
.topic-image, .question-image, .flash-image, .option-image { border-radius: var(--radius-sm); object-fit: cover; border: 1px solid var(--line); }
.topic-image { width: 100%; max-height: 260px; }
.question-image { width: 100%; max-height: 360px; margin: .75rem 0; }
.flash-image { width: 100%; max-height: 280px; margin: .8rem 0; }
.option-image { width: 100%; max-height: 180px; margin-bottom: .6rem; }
.progress { height: 10px; background: var(--surface-2); border-radius: 999px; overflow: hidden; }
.progress span { display: block; height: 100%; width: var(--value, 0%); border-radius: inherit; background: linear-gradient(90deg, var(--primary), var(--accent)); }
.sticky-progress { position: sticky; top: 76px; z-index: 18; margin-bottom: 1rem; }

.actions, .toolbar, .button-row { display: flex; flex-wrap: wrap; gap: .7rem; align-items: center; }
.button, .ghost-button, .danger-button, .success-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: .72rem 1.05rem;
  border-radius: 14px;
  border: 1px solid transparent;
  font-weight: 800;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.button { color: #fff; background: linear-gradient(135deg, var(--primary), var(--primary-2)); box-shadow: 0 16px 34px rgba(37, 99, 235, .22); }
.button:hover, .ghost-button:hover, .danger-button:hover, .success-button:hover { transform: translateY(-1px); }
.ghost-button { color: var(--text); background: var(--surface); border-color: var(--line); }
.danger-button { color: #fff; background: var(--danger); }
.success-button { color: #fff; background: var(--success); }
.badge, .chips span {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: .25rem .6rem;
  border-radius: 999px;
  background: var(--surface-2);
  color: var(--muted);
  font-weight: 700;
  font-size: .82rem;
}
.chips { display: flex; flex-wrap: wrap; gap: .45rem; }

.quiz-frame, .flash-stage { max-width: 850px; margin: 0 auto; }
.option-grid { display: grid; grid-template-columns: 1fr; gap: .8rem; margin-top: 1rem; }
.option {
  width: 100%;
  text-align: left;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 1rem;
  background: var(--option-bg, var(--surface));
  color: var(--option-fg, var(--text));
  font-weight: 800;
  box-shadow: var(--shadow-soft);
  transition: transform .18s ease, opacity .18s ease, border .18s ease;
}
.option:hover { transform: translateY(-1px); }
.option.correct { background: var(--success) !important; color: #fff !important; border-color: transparent; }
.option.wrong { background: var(--danger) !important; color: #fff !important; border-color: transparent; }
.flashcard { perspective: 1400px; min-height: 330px; }
.flash-face {
  min-height: 330px;
  display: grid;
  align-content: center;
  text-align: center;
  gap: .7rem;
  border-radius: 28px;
  background: linear-gradient(135deg, color-mix(in srgb, var(--primary) 9%, var(--surface)), color-mix(in srgb, var(--accent) 10%, var(--surface)));
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  padding: clamp(1.2rem, 4vw, 2rem);
}
.flash-back { background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 14%, var(--surface)), color-mix(in srgb, var(--primary-2) 11%, var(--surface))); }

.field { display: grid; gap: .4rem; }
.field label { color: var(--muted); font-weight: 800; font-size: .9rem; }
input, select, textarea, .search-input {
  width: 100%;
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: .72rem .88rem;
  background: var(--surface);
  color: var(--text);
  outline: none;
}
textarea { min-height: 110px; resize: vertical; }
input:focus, select:focus, textarea:focus { border-color: color-mix(in srgb, var(--primary) 65%, var(--line)); box-shadow: 0 0 0 4px color-mix(in srgb, var(--primary) 15%, transparent); }

.table-wrap { overflow: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); }
table { width: 100%; border-collapse: collapse; min-width: 720px; }
th, td { padding: .9rem; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-size: .88rem; }
tr:last-child td { border-bottom: 0; }
.admin-shell { display: grid; gap: 1rem; }
.admin-nav { display: flex; flex-wrap: wrap; gap: .6rem; align-items: center; }
.admin-body { display: grid; gap: 1rem; }
.empty { text-align: center; color: var(--muted); }

.site-footer {
  width: min(1200px, calc(100% - 2rem));
  margin: 3rem auto 1rem;
  padding: clamp(1rem, 3vw, 1.6rem);
  background: color-mix(in srgb, var(--surface) 94%, transparent);
  border: 1px solid var(--line);
  border-radius: 28px;
  box-shadow: var(--shadow-soft);
}
.footer-grid { display: grid; gap: 1.2rem; }
.footer-brand img { width: min(270px, 100%); height: auto; margin-bottom: .7rem; }
.site-footer h3 { margin-bottom: .75rem; }
.site-footer a { display: block; color: var(--muted); padding: .18rem 0; }
.site-footer a:hover { color: var(--primary); }
.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: .75rem;
  margin-top: 1.2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: .92rem;
}
.backend-pill { display: inline-flex; margin-top: .4rem; padding: .35rem .7rem; border-radius: 999px; background: var(--surface-2); color: var(--muted); font-weight: 800; }
.backend-pill.online { background: color-mix(in srgb, var(--success) 14%, var(--surface-2)); color: var(--success); }

.toast {
  position: fixed;
  left: 50%;
  bottom: 1.2rem;
  z-index: 80;
  transform: translate(-50%, 120%);
  opacity: 0;
  padding: .8rem 1rem;
  border-radius: 999px;
  background: var(--text);
  color: var(--bg);
  box-shadow: var(--shadow);
  transition: .25s ease;
}
.toast.show { transform: translate(-50%, 0); opacity: 1; }

@media (min-width: 760px) {
  .two { grid-template-columns: repeat(2, 1fr); }
  .three { grid-template-columns: repeat(3, 1fr); }
  .stats { grid-template-columns: repeat(4, 1fr); }
  .option-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: 1.4fr .7fr .7fr 1fr; }
  .admin-shell { grid-template-columns: 220px 1fr; align-items: start; }
  .admin-nav { position: sticky; top: 96px; display: grid; }
}

@media (min-width: 920px) {
  .hero-grid { grid-template-columns: 1.1fr .9fr; }
  .nav-toggle { display: none; }
  .top-nav { display: flex; }
}

@media (max-width: 520px) {
  .brand-copy small { display: none; }
  .brand-mark { width: 42px; height: 42px; }
  .hero h1 { font-size: clamp(2.75rem, 15vw, 4rem); }
  .actions a, .actions button { width: 100%; }
  .section-head { align-items: stretch; flex-direction: column; }
}

/* Full-screen Kahoot-inspired QuizLuck study mode */
body.study-active {
  overflow: hidden;
  background:
    radial-gradient(circle at 18% 12%, rgba(255, 255, 255, .22), transparent 18rem),
    radial-gradient(circle at 90% 70%, rgba(236, 72, 153, .28), transparent 26rem),
    linear-gradient(135deg, #2d026f 0%, #5f13c7 38%, #8b1ee6 70%, #260047 100%);
  color: #fff;
}
body.study-active::before,
body.study-active::after {
  content: "";
  position: fixed;
  inset: auto auto -18vw -10vw;
  width: 58vw;
  height: 58vw;
  border-radius: 999px;
  background: rgba(255,255,255,.09);
  transform: rotate(-18deg);
  pointer-events: none;
}
body.study-active::after {
  inset: -16vw -12vw auto auto;
  width: 52vw;
  height: 52vw;
  background: rgba(255,255,255,.075);
}
body.study-active .shell-header,
body.study-active .site-footer { display: none !important; }
body.study-active .app-shell {
  width: 100%;
  height: 100dvh;
  max-width: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
}
.study-screen {
  position: relative;
  width: 100vw;
  height: 100dvh;
  overflow: hidden;
  isolation: isolate;
}
.study-close {
  position: fixed;
  z-index: 90;
  top: calc(env(safe-area-inset-top) + 14px);
  left: calc(env(safe-area-inset-left) + 14px);
  display: grid;
  place-items: center;
  width: 54px;
  height: 54px;
  border-radius: 18px;
  background: rgba(12, 10, 35, .45);
  border: 1px solid rgba(255,255,255,.22);
  color: #fff;
  font-size: 2rem;
  font-weight: 900;
  line-height: 1;
  box-shadow: 0 18px 60px rgba(0,0,0,.28);
  backdrop-filter: blur(18px) saturate(1.4);
  transition: transform .18s ease, background .18s ease;
}
.study-close:hover { transform: scale(1.04); background: rgba(12, 10, 35, .7); }
.study-progress-line {
  position: fixed;
  z-index: 85;
  top: calc(env(safe-area-inset-top) + 31px);
  left: calc(env(safe-area-inset-left) + 96px);
  right: calc(env(safe-area-inset-right) + 26px);
  height: 8px;
  border-radius: 999px;
  background: rgba(255,255,255,.28);
  overflow: hidden;
  box-shadow: inset 0 1px 2px rgba(0,0,0,.22), 0 12px 32px rgba(0,0,0,.12);
}
.study-progress-line span {
  display: block;
  width: var(--value, 0%);
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, #00e5ff, #35ff99, #fff12b);
  transition: width .34s ease;
}
.study-deck {
  height: 100dvh;
  display: flex;
  overflow-x: auto;
  overflow-y: hidden;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.study-deck::-webkit-scrollbar { display: none; }
.study-slide {
  flex: 0 0 100vw;
  width: 100vw;
  height: 100dvh;
  scroll-snap-align: center;
  scroll-snap-stop: always;
  display: grid;
  place-items: center;
  padding: calc(env(safe-area-inset-top) + 58px) clamp(.7rem, 3vw, 2rem) calc(env(safe-area-inset-bottom) + 12px);
}
.study-card.kahoot-card {
  position: relative;
  width: min(1160px, 100%);
  height: min(780px, calc(100dvh - 82px));
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: clamp(.55rem, 1.1vw, .85rem);
  padding: clamp(.72rem, 1.5vw, 1.05rem);
  border-radius: clamp(20px, 2.6vw, 30px);
  background: linear-gradient(135deg, rgba(255,255,255,.22), rgba(255,255,255,.12));
  border: 1px solid rgba(255,255,255,.22);
  box-shadow: 0 34px 110px rgba(0,0,0,.28);
  backdrop-filter: blur(22px) saturate(1.35);
  overflow: hidden;
  transition: transform .25s ease, border-color .25s ease;
}
.study-card.kahoot-card::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(120deg, rgba(255,255,255,.13), transparent 38%),
    radial-gradient(circle at 80% 12%, rgba(255,255,255,.16), transparent 20rem);
}
.study-card-head.compact {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .65rem;
  min-height: 40px;
}
.mini-brand {
  display: inline-flex;
  align-items: center;
  gap: .05rem;
  padding: .48rem .72rem;
  border-radius: 999px;
  color: #fff;
  background: rgba(0,0,0,.18);
  border: 1px solid rgba(255,255,255,.16);
  font-weight: 1000;
  letter-spacing: -.02em;
  text-shadow: 0 2px 0 rgba(0,0,0,.18);
}
.mini-brand span { color: #2ff4d8; }
.study-count {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 74px;
  height: 40px;
  padding: 0 .85rem;
  border-radius: 999px;
  background: rgba(0,0,0,.24);
  color: #fff;
  border: 1px solid rgba(255,255,255,.18);
  font-weight: 1000;
  box-shadow: inset 0 1px 0 rgba(255,255,255,.12);
}
.study-content.kahoot-content {
  min-height: 0;
  display: grid;
  grid-template-rows: minmax(84px, 30%) auto minmax(0, 1fr);
  gap: clamp(.5rem, 1.1vw, .8rem);
}
.study-media {
  position: relative;
  width: min(520px, 62%);
  height: 100%;
  min-height: 90px;
  justify-self: center;
  display: grid;
  place-items: center;
  overflow: hidden;
}
.study-media.has-image .question-image {
  width: 100%;
  max-height: 100%;
  object-fit: contain;
  border-radius: 14px;
  background: #fff;
  border: 0;
  box-shadow: 0 18px 44px rgba(0,0,0,.24);
}
.study-media.no-image {
  width: min(470px, 70%);
  border-radius: 28px;
  background: linear-gradient(135deg, rgba(255,255,255,.22), rgba(255,255,255,.09));
  border: 1px solid rgba(255,255,255,.18);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.16), 0 20px 60px rgba(0,0,0,.14);
}
.emoji-orb {
  width: clamp(82px, 10vw, 145px);
  height: clamp(82px, 10vw, 145px);
  display: grid;
  place-items: center;
  border-radius: 34px;
  background: linear-gradient(135deg, rgba(255,255,255,.92), rgba(255,255,255,.72));
  box-shadow: 0 20px 52px rgba(0,0,0,.18);
  transform: rotate(-4deg);
}
.emoji-orb span { font-size: clamp(3rem, 7vw, 5.8rem); filter: drop-shadow(0 4px 0 rgba(0,0,0,.10)); }
.emoji-caption {
  position: absolute;
  right: 16px;
  bottom: 12px;
  display: grid;
  text-align: right;
  color: #fff;
  text-shadow: 0 2px 8px rgba(0,0,0,.25);
}
.emoji-caption strong { font-size: .95rem; font-weight: 1000; }
.emoji-caption small { opacity: .85; font-size: .76rem; }
.study-question {
  width: min(920px, 100%);
  justify-self: center;
  margin: 0;
  padding: clamp(.65rem, 1.4vw, 1rem) clamp(.85rem, 2vw, 1.35rem);
  color: #221d2b;
  background: rgba(255,255,255,.78);
  border-radius: 12px;
  text-align: center;
  font-size: clamp(1.2rem, 3.35vw, 2.65rem);
  line-height: 1.08;
  letter-spacing: -.045em;
  text-shadow: none;
  box-shadow: inset 18vw 0 0 rgba(255,255,255,.18), inset -18vw 0 0 rgba(255,255,255,.12);
  max-height: 18dvh;
  overflow: hidden;
}
.study-options.kahoot-options {
  min-height: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(.45rem, 1vw, .72rem);
}
.study-option.kahoot-option {
  width: 100%;
  min-height: clamp(70px, 12dvh, 108px);
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: clamp(.6rem, 1.2vw, .9rem);
  padding: clamp(.58rem, 1.2vw, .9rem);
  border: 0;
  border-radius: 10px;
  color: #fff;
  text-align: center;
  font-weight: 1000;
  font-size: clamp(1.05rem, 2.4vw, 1.68rem);
  box-shadow: inset 0 -6px 0 rgba(0,0,0,.22), 0 14px 26px rgba(0,0,0,.14);
  text-shadow: 0 2px 0 rgba(0,0,0,.24);
  overflow: hidden;
  transition: transform .12s ease, filter .16s ease, opacity .16s ease;
}
.study-option.kahoot-option:hover { transform: translateY(-2px) scale(1.006); filter: brightness(1.05); }
.kahoot-option.option-0 { background: #e81b3a; }
.kahoot-option.option-1 { background: #1368ce; }
.kahoot-option.option-2 { background: #d89e00; }
.kahoot-option.option-3 { background: #26890c; }
.option-shape {
  display: grid;
  place-items: center;
  width: clamp(30px, 4.2vw, 46px);
  height: clamp(30px, 4.2vw, 46px);
  color: #fff;
  font-size: clamp(1.1rem, 2.5vw, 1.55rem);
  filter: drop-shadow(0 2px 0 rgba(0,0,0,.22));
}
.option-label { min-width: 0; display: grid; place-items: center; }
.option-label strong {
  max-width: 100%;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
}
.study-option.correct { background: #52c41a !important; color: #fff !important; }
.study-option.wrong { background: #ff3355 !important; color: #fff !important; }
.study-option.dimmed { opacity: .45; filter: grayscale(.1) brightness(.85); }
.option-image {
  width: min(240px, 100%);
  max-height: 110px;
  object-fit: contain;
  margin: 0 auto .4rem;
  border-radius: 10px;
  background: rgba(255,255,255,.9);
  border: 0;
}
.study-card.is-correct { border-color: rgba(82,196,26,.75); }
.study-card.is-wrong {
  border-color: rgba(255, 51, 85, .8);
  animation: studyShake .48s cubic-bezier(.36,.07,.19,.97) both;
}
@keyframes studyShake {
  10%, 90% { transform: translateX(-2px) rotate(-.1deg); }
  20%, 80% { transform: translateX(5px) rotate(.2deg); }
  30%, 50%, 70% { transform: translateX(-10px) rotate(-.35deg); }
  40%, 60% { transform: translateX(10px) rotate(.35deg); }
}
.result-ribbon {
  position: absolute;
  z-index: 14;
  top: 44%;
  left: -8%;
  right: -8%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: .65rem;
  min-height: clamp(58px, 8vw, 92px);
  color: #fff;
  font-size: clamp(1.65rem, 4.5vw, 3.2rem);
  font-weight: 1000;
  letter-spacing: -.035em;
  text-shadow: 0 3px 0 rgba(0,0,0,.22);
  transform: rotate(-3.8deg);
  box-shadow: 0 20px 50px rgba(0,0,0,.22);
  animation: ribbonDrop .22s ease both;
}
.result-ribbon.good { background: #52c41a; }
.result-ribbon.bad { background: #ff3355; }
.result-ribbon span {
  display: inline-grid;
  place-items: center;
  width: clamp(38px, 5vw, 58px);
  height: clamp(38px, 5vw, 58px);
  border-radius: 999px;
  background: rgba(255,255,255,.18);
  border: 2px solid rgba(255,255,255,.28);
}
@keyframes ribbonDrop { from { opacity: 0; transform: translateY(-8px) rotate(-3.8deg) scale(.98); } to { opacity: 1; transform: translateY(0) rotate(-3.8deg) scale(1); } }
body.study-feedback-correct .study-screen::before,
body.study-feedback-wrong .study-screen::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 8;
  animation: feedbackFade 1.35s ease forwards;
}
body.study-feedback-correct .study-screen::before { background: rgba(82,196,26,.16); }
body.study-feedback-wrong .study-screen::before { background: rgba(255,51,85,.20); }
@keyframes feedbackFade { from { opacity: 1; } to { opacity: 0; } }
.wrong-popup {
  position: relative;
  z-index: 15;
  align-self: end;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .8rem;
  padding: clamp(.7rem, 1.3vw, 1rem);
  border-radius: 16px;
  background: linear-gradient(135deg, #ff3355, #b80f2f);
  color: #fff;
  box-shadow: 0 24px 70px rgba(255,51,85,.35);
  animation: popupIn .22s ease both;
}
.wrong-popup strong { display: block; font-size: clamp(1rem, 2vw, 1.25rem); line-height: 1.1; }
.wrong-popup p { margin: .15rem 0 0; font-weight: 1000; }
.wrong-popup small { display: block; margin-top: .1rem; opacity: .92; }
.wrong-actions { display: flex; flex: 0 0 auto; flex-wrap: wrap; gap: .5rem; }
.wrong-popup .ghost-button { background: rgba(255,255,255,.16); color: #fff; border-color: rgba(255,255,255,.38); box-shadow: none; }
.wrong-popup .button { background: #fff; color: #b80f2f; box-shadow: none; }
@keyframes popupIn { from { opacity: 0; transform: translateY(10px) scale(.98); } to { opacity: 1; transform: translateY(0) scale(1); } }
.study-bottom-actions.clean-actions,
.study-bottom-actions.auto-note {
  position: relative;
  z-index: 12;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: .55rem;
  align-items: center;
  color: #fff;
}
.study-bottom-actions.clean-actions .ghost-button,
.study-bottom-actions.clean-actions .success-button,
.study-bottom-actions.clean-actions .danger-button,
.study-bottom-actions.auto-note .button {
  min-height: 42px;
  border-radius: 999px;
  background: rgba(255,255,255,.16);
  color: #fff;
  border-color: rgba(255,255,255,.22);
  box-shadow: none;
  backdrop-filter: blur(12px);
}
.study-bottom-actions.clean-actions .success-button { background: rgba(38,137,12,.86); }
.study-bottom-actions.clean-actions .danger-button { background: rgba(232,27,58,.86); }
.study-bottom-actions.auto-note span {
  padding: .55rem .8rem;
  border-radius: 999px;
  background: rgba(0,0,0,.20);
  border: 1px solid rgba(255,255,255,.12);
  font-weight: 900;
}
.finish-screen { display: grid; place-items: center; padding: 1rem; }
.finish-card {
  width: min(860px, 100%);
  padding: clamp(1rem, 3vw, 2rem);
  border-radius: 32px;
  background: rgba(255,255,255,.92);
  color: #0f172a;
  border: 1px solid rgba(255,255,255,.55);
  box-shadow: 0 30px 90px rgba(0,0,0,.22);
}
@media (max-width: 760px) {
  .study-close { width: 46px; height: 46px; border-radius: 15px; font-size: 1.75rem; }
  .study-progress-line { top: calc(env(safe-area-inset-top) + 28px); left: calc(env(safe-area-inset-left) + 76px); right: 12px; height: 7px; }
  .study-slide { padding: calc(env(safe-area-inset-top) + 60px) .5rem calc(env(safe-area-inset-bottom) + 8px); }
  .study-card.kahoot-card { height: calc(100dvh - 72px); padding: .55rem; border-radius: 22px; gap: .42rem; }
  .study-card-head.compact { min-height: 34px; }
  .mini-brand { font-size: .78rem; padding: .36rem .54rem; }
  .study-count { min-width: 54px; height: 32px; font-size: .78rem; }
  .study-content.kahoot-content { grid-template-rows: minmax(70px, 26%) auto minmax(0, 1fr); gap: .42rem; }
  .study-media { width: min(360px, 76%); min-height: 72px; }
  .study-media.no-image { border-radius: 22px; }
  .emoji-orb { width: clamp(70px, 18vw, 96px); height: clamp(70px, 18vw, 96px); border-radius: 24px; }
  .emoji-orb span { font-size: clamp(2.75rem, 12vw, 4rem); }
  .emoji-caption { display: none; }
  .study-question { font-size: clamp(1.05rem, 5.6vw, 1.85rem); line-height: 1.08; max-height: 17dvh; padding: .58rem .66rem; }
  .study-options.kahoot-options { grid-template-columns: 1fr; gap: .4rem; }
  .study-option.kahoot-option { min-height: 56px; font-size: clamp(.95rem, 4.6vw, 1.22rem); border-radius: 10px; padding: .46rem .52rem; box-shadow: inset 0 -4px 0 rgba(0,0,0,.22); }
  .option-shape { width: 28px; height: 28px; font-size: 1rem; }
  .option-label strong { -webkit-line-clamp: 2; }
  .result-ribbon { top: 42%; min-height: 54px; font-size: clamp(1.35rem, 8vw, 2.1rem); }
  .wrong-popup { flex-direction: column; align-items: stretch; gap: .55rem; border-radius: 14px; padding: .62rem; }
  .wrong-actions { display: grid; grid-template-columns: 1fr 1fr; }
  .wrong-popup .button, .wrong-popup .ghost-button { min-height: 40px; padding: .48rem .65rem; }
  .wrong-popup small { display: none; }
  .study-bottom-actions.clean-actions .ghost-button,
  .study-bottom-actions.clean-actions .success-button,
  .study-bottom-actions.clean-actions .danger-button { min-height: 38px; padding: .45rem .62rem; font-size: .85rem; flex: 1 1 auto; }
}
@media (max-width: 430px) {
  .study-content.kahoot-content { grid-template-rows: minmax(62px, 22%) auto minmax(0, 1fr); }
  .study-media { width: min(280px, 70%); }
  .study-question { font-size: clamp(1rem, 5vw, 1.45rem); }
  .study-option.kahoot-option { min-height: 50px; }
  .study-bottom-actions.clean-actions { gap: .35rem; }
}

/* QuizLuck v2.2 polish: locked wrong answers, AdSense space, adaptive text, top feedback */
body.study-active {
  height: 100dvh;
  overflow: hidden !important;
  overscroll-behavior: none;
}
.study-deck.lock-scroll {
  overflow-x: hidden !important;
  scroll-snap-type: none;
}
.study-ad-slot {
  position: fixed;
  z-index: 86;
  top: calc(env(safe-area-inset-top) + 46px);
  right: calc(env(safe-area-inset-right) + 24px);
  width: min(320px, 34vw);
  height: 50px;
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: .5rem;
  padding: .35rem .7rem;
  border-radius: 14px;
  background: rgba(255,255,255,.12);
  border: 1px dashed rgba(255,255,255,.34);
  color: rgba(255,255,255,.86);
  box-shadow: 0 12px 38px rgba(0,0,0,.12);
  backdrop-filter: blur(14px) saturate(1.25);
  pointer-events: none;
}
.study-ad-slot span {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 10px;
  background: rgba(0,0,0,.20);
  font-weight: 1000;
  font-size: .78rem;
  letter-spacing: .08em;
  text-transform: uppercase;
}
.study-ad-slot small {
  font-weight: 900;
  font-size: .8rem;
  opacity: .82;
}
.result-ribbon {
  top: clamp(58px, 8dvh, 78px) !important;
  left: 50% !important;
  right: auto !important;
  width: min(430px, calc(100% - 2rem));
  min-height: 54px !important;
  padding: .5rem .9rem;
  border-radius: 999px;
  transform: translateX(-50%) rotate(0deg) !important;
  font-size: clamp(1.2rem, 2.7vw, 2rem) !important;
  box-shadow: 0 18px 45px rgba(0,0,0,.22);
  pointer-events: none;
}
@keyframes ribbonDrop {
  from { opacity: 0; transform: translate(-50%, -8px) scale(.97); }
  to { opacity: 1; transform: translate(-50%, 0) scale(1); }
}
.study-content.kahoot-content {
  grid-template-rows: minmax(74px, 24%) auto minmax(0, 1fr);
}
.study-card.kahoot-card.is-wrong .study-content.kahoot-content,
.study-card.kahoot-card.is-correct .study-content.kahoot-content {
  padding-top: clamp(18px, 5dvh, 48px);
}
.study-question {
  display: flex;
  align-items: center;
  justify-content: center;
  overflow-wrap: anywhere;
  hyphens: auto;
  font-size: clamp(1.12rem, 2.55vw, 2.28rem) !important;
  min-height: clamp(70px, 12dvh, 132px);
  max-height: none !important;
}
.study-question.text-md { font-size: clamp(1.05rem, 2.2vw, 2rem) !important; }
.study-question.text-lg { font-size: clamp(.98rem, 1.9vw, 1.72rem) !important; line-height: 1.12; }
.study-question.text-xl { font-size: clamp(.9rem, 1.55vw, 1.38rem) !important; line-height: 1.16; letter-spacing: -.025em; }
.study-question.text-xxl { font-size: clamp(.82rem, 1.28vw, 1.12rem) !important; line-height: 1.18; letter-spacing: -.01em; }
.study-option.kahoot-option {
  min-height: clamp(64px, 10.4dvh, 102px);
  font-size: clamp(1rem, 2vw, 1.48rem) !important;
}
.option-label strong {
  overflow-wrap: anywhere;
  hyphens: auto;
  -webkit-line-clamp: 4;
  line-height: 1.08;
}
.option-text-lg strong { font-size: .88em; line-height: 1.12; }
.option-text-xl strong { font-size: .76em; line-height: 1.14; -webkit-line-clamp: 5; }
.option-text-xxl strong { font-size: .66em; line-height: 1.16; -webkit-line-clamp: 6; }
.wrong-popup {
  min-height: 74px;
  max-height: 128px;
  overflow: hidden;
  align-self: stretch;
  margin-top: .2rem;
}
.wrong-popup p,
.wrong-popup small {
  overflow: hidden;
  display: -webkit-box;
  -webkit-box-orient: vertical;
}
.wrong-popup p { -webkit-line-clamp: 1; }
.wrong-popup small { -webkit-line-clamp: 2; }
@media (max-width: 900px) {
  .study-ad-slot {
    top: calc(env(safe-area-inset-top) + 42px);
    right: 12px;
    width: min(260px, 46vw);
    height: 42px;
    opacity: .76;
  }
  .study-ad-slot small { font-size: .72rem; }
}
@media (max-width: 760px) {
  .study-ad-slot {
    top: calc(env(safe-area-inset-top) + 70px);
    left: 50%;
    right: auto;
    transform: translateX(-50%);
    width: min(320px, calc(100vw - 7rem));
    height: 38px;
    opacity: .62;
  }
  .study-ad-slot span { width: 26px; height: 26px; border-radius: 8px; font-size: .68rem; }
  .study-card.kahoot-card { height: calc(100dvh - 82px); }
  .study-content.kahoot-content { grid-template-rows: minmax(54px, 19%) auto minmax(0, 1fr); }
  .study-card.kahoot-card.is-wrong .study-content.kahoot-content,
  .study-card.kahoot-card.is-correct .study-content.kahoot-content { padding-top: 34px; }
  .study-question {
    min-height: clamp(64px, 14dvh, 112px);
    font-size: clamp(.98rem, 4.8vw, 1.52rem) !important;
  }
  .study-question.text-md { font-size: clamp(.92rem, 4.2vw, 1.36rem) !important; }
  .study-question.text-lg { font-size: clamp(.84rem, 3.65vw, 1.12rem) !important; }
  .study-question.text-xl { font-size: clamp(.76rem, 3.05vw, .98rem) !important; }
  .study-question.text-xxl { font-size: clamp(.7rem, 2.55vw, .86rem) !important; }
  .study-option.kahoot-option { min-height: 52px; font-size: clamp(.86rem, 3.8vw, 1.05rem) !important; }
  .option-text-lg strong { font-size: .84em; }
  .option-text-xl strong { font-size: .72em; }
  .option-text-xxl strong { font-size: .62em; }
  .result-ribbon { top: 46px !important; width: min(300px, calc(100% - 5rem)); min-height: 44px !important; }
  .wrong-popup { max-height: 108px; }
}
@media (max-width: 430px) {
  .study-ad-slot { width: min(260px, calc(100vw - 6.5rem)); }
  .study-question { min-height: 58px; }
  .wrong-popup { max-height: 98px; }
}


/* QuizLuck v2.3: true horizontal one-by-one deck. No more reset animation from question 1. */
.study-deck {
  scroll-behavior: auto !important;
  overscroll-behavior-x: contain;
  touch-action: pan-x;
  will-change: scroll-position;
}
.study-deck.instant-position {
  scroll-snap-type: none !important;
  scroll-behavior: auto !important;
}
.study-slide {
  scroll-snap-align: start !important;
  contain: layout paint style;
}
.study-nav-arrow {
  position: fixed;
  z-index: 95;
  top: 50%;
  transform: translateY(-50%);
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255,255,255,.22);
  border-radius: 999px;
  background: rgba(12, 10, 35, .52);
  color: #fff;
  font-size: 2.1rem;
  font-weight: 1000;
  line-height: 1;
  box-shadow: 0 18px 50px rgba(0,0,0,.26);
  backdrop-filter: blur(16px) saturate(1.4);
  cursor: pointer;
  transition: transform .18s ease, opacity .18s ease, background .18s ease;
}
.study-nav-arrow:hover { transform: translateY(-50%) scale(1.06); background: rgba(12, 10, 35, .72); }
.study-nav-arrow:disabled { opacity: .28; cursor: not-allowed; transform: translateY(-50%) scale(.96); }
.study-nav-arrow.prev { left: calc(env(safe-area-inset-left) + 20px); }
.study-nav-arrow.next { right: calc(env(safe-area-inset-right) + 20px); }
@media (max-width: 760px) {
  .study-nav-arrow {
    width: 42px;
    height: 42px;
    font-size: 1.65rem;
    top: auto;
    bottom: calc(env(safe-area-inset-bottom) + 16px);
    transform: none;
  }
  .study-nav-arrow:hover { transform: scale(1.04); }
  .study-nav-arrow:disabled { transform: scale(.96); }
  .study-nav-arrow.prev { left: 12px; }
  .study-nav-arrow.next { right: 12px; }
}

/* QuizLuck explanation + no-repeat final polish */
.study-explanation-panel {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  align-items: start;
  width: min(100%, 980px);
  margin: 12px auto 0;
  padding: 16px 18px;
  border-radius: 22px;
  border: 1px solid rgba(255,255,255,.42);
  background: rgba(255,255,255,.90);
  color: #101828;
  box-shadow: 0 18px 45px rgba(15,23,42,.16);
  text-align: left;
  backdrop-filter: blur(14px);
}
.study-explanation-panel.wrong {
  border-color: rgba(255,255,255,.55);
  background: linear-gradient(135deg, rgba(255,255,255,.96), rgba(255,236,241,.94));
}
.study-explanation-panel.correct {
  background: linear-gradient(135deg, rgba(255,255,255,.96), rgba(231,255,245,.94));
}
.study-explanation-panel .explain-icon {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 16px;
  background: rgba(79,70,229,.12);
  font-size: 24px;
}
.study-explanation-panel strong {
  display: block;
  font-size: clamp(18px, 2vw, 24px);
  margin-bottom: 4px;
}
.study-explanation-panel p {
  margin: 4px 0 0;
  font-size: clamp(14px, 1.45vw, 17px);
  line-height: 1.45;
  color: #263248;
}
.study-explanation-panel .correct-line {
  color: #0f5132;
  font-weight: 700;
}
.wrong-popup.compact-review {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
}
.wrong-popup.compact-review p { margin: 4px 0 0; }
.setting-toggle {
  display: flex !important;
  flex-direction: row !important;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: rgba(255,255,255,.70);
}
.setting-toggle span {
  display: grid;
  gap: 4px;
}
.setting-toggle small {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.35;
}
.setting-toggle input[type="checkbox"] {
  width: 22px;
  height: 22px;
  min-width: 22px;
}
.import-help {
  margin-top: 18px;
  padding: 14px;
  border-radius: 16px;
  background: rgba(37, 99, 235, .08);
  color: var(--text);
}
.import-help code {
  margin-left: 8px;
  padding: 4px 8px;
  border-radius: 10px;
  background: rgba(15, 23, 42, .08);
}
.study-bottom-actions.auto-note {
  flex-wrap: wrap;
}
.study-bottom-actions.auto-note .ghost-button,
.study-bottom-actions.auto-note .button {
  min-width: 150px;
}
@media (max-width: 760px) {
  .study-explanation-panel {
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 13px 14px;
    border-radius: 18px;
  }
  .study-explanation-panel .explain-icon {
    width: 38px;
    height: 38px;
    border-radius: 14px;
    font-size: 21px;
  }
  .wrong-popup.compact-review {
    align-items: stretch;
    flex-direction: column;
  }
}

/* QuizLuck v2.4 student preference toolbar + bilingual study text */
.student-study-toolbar {
  position: fixed;
  top: 18px;
  right: 18px;
  z-index: 60;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  border: 1px solid rgba(255,255,255,.22);
  border-radius: 22px;
  background: rgba(20, 10, 58, .54);
  color: #fff;
  box-shadow: 0 18px 45px rgba(0,0,0,.24);
  backdrop-filter: blur(20px);
}
.mini-switch-row,
.mini-lang-row {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 900;
  font-size: 13px;
  letter-spacing: -.01em;
  white-space: nowrap;
}
.mini-switch-row input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}
.mini-switch-row i {
  position: relative;
  width: 44px;
  height: 25px;
  border-radius: 999px;
  background: rgba(255,255,255,.26);
  box-shadow: inset 0 0 0 1px rgba(255,255,255,.22);
  cursor: pointer;
  transition: .2s ease;
}
.mini-switch-row i::after {
  content: "";
  position: absolute;
  top: 4px;
  left: 4px;
  width: 17px;
  height: 17px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 4px 14px rgba(0,0,0,.20);
  transition: .2s ease;
}
.mini-switch-row input:checked + i {
  background: linear-gradient(135deg, #21d4bd, #54e346);
}
.mini-switch-row input:checked + i::after {
  transform: translateX(19px);
}
.mini-lang-row select {
  height: 34px;
  border: 1px solid rgba(255,255,255,.24);
  border-radius: 999px;
  padding: 0 34px 0 12px;
  background: rgba(255,255,255,.94);
  color: #0f172a;
  font-weight: 900;
  outline: none;
}
.dual-study-text,
.dual-option-text {
  display: grid;
  gap: 5px;
  align-items: center;
}
.english-main {
  display: block;
}
.translated-line {
  display: block;
  font-size: .64em;
  line-height: 1.22;
  opacity: .88;
  font-weight: 800;
}
.dual-option-text .translated-line {
  font-size: .66em;
  opacity: .9;
}
.translated-explanation {
  margin-top: 8px !important;
  padding-top: 8px;
  border-top: 1px dashed rgba(15,23,42,.16);
}
.import-help {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  align-items: center;
}
.import-help code {
  margin-left: 0 !important;
}
.study-card .study-question .dual-study-text {
  max-width: 100%;
}
.study-card .option-label strong {
  width: 100%;
}
.study-card .option-label .dual-option-text {
  width: 100%;
}
@media (max-width: 980px) {
  .student-study-toolbar {
    top: auto;
    right: 12px;
    bottom: 12px;
    gap: 8px;
    padding: 7px 8px;
  }
  .mini-switch-row,
  .mini-lang-row {
    font-size: 12px;
  }
  .mini-switch-row i {
    width: 40px;
    height: 23px;
  }
  .mini-switch-row i::after {
    width: 15px;
    height: 15px;
  }
  .mini-switch-row input:checked + i::after {
    transform: translateX(17px);
  }
  .mini-lang-row select {
    height: 31px;
    max-width: 96px;
    padding-left: 10px;
  }
}
@media (max-width: 560px) {
  .student-study-toolbar {
    left: 12px;
    right: 12px;
    justify-content: space-between;
    border-radius: 18px;
  }
  .student-study-toolbar .mini-lang-row span,
  .student-study-toolbar .mini-switch-row span {
    display: none;
  }
  .translated-line {
    font-size: .58em;
  }
}

/* QuizLuck v2.5 one-file import and flashcard explanation polish */
.import-report { margin-top: 14px; }
.flash-explanation-always {
  width: min(100%, 760px);
  margin: 10px auto 0;
  padding: 16px 18px;
  border-radius: 20px;
  background: rgba(255,255,255,.74);
  border: 1px solid rgba(15,23,42,.10);
  box-shadow: 0 14px 34px rgba(15,23,42,.12);
  text-align: left;
}
.flash-explanation-always strong {
  display: block;
  color: var(--primary);
  font-size: clamp(16px, 1.8vw, 22px);
  margin-bottom: 4px;
}
.flash-explanation-always p {
  margin: 4px 0 0;
  color: var(--text);
  line-height: 1.48;
  font-size: clamp(14px, 1.5vw, 17px);
}
.flash-face h1 .dual-study-text,
.flash-face h1 .english-main,
.flash-face h1 .translated-line {
  display: block;
}
@media (max-width: 720px) {
  .flash-explanation-always { padding: 13px 14px; border-radius: 16px; }
  .import-help code { display: inline-flex; margin: 5px 5px 0 0; }
}

/* QuizLuck v2.7 premium flashcard + saved-only controls */
.study-session-pill{
  position:fixed;top:70px;left:50%;transform:translateX(-50%);z-index:20;
  display:inline-flex;align-items:center;gap:8px;padding:10px 16px;border-radius:999px;
  color:#fff;background:rgba(15,23,42,.34);border:1px solid rgba(255,255,255,.22);
  font-weight:900;box-shadow:0 14px 34px rgba(0,0,0,.18);backdrop-filter:blur(14px)
}
.topic-hero-section{padding-top:40px}.premium-topic-card{text-align:center;overflow:hidden}.topic-emoji-hero{width:96px;height:96px;margin:0 auto 18px;display:grid;place-items:center;border-radius:30px;font-size:54px;background:linear-gradient(135deg,#e0f2fe,#f5d0fe);box-shadow:0 22px 50px rgba(79,70,229,.18)}
.topic-mode-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin-top:18px}.mode-launch{min-height:76px;display:flex!important;flex-direction:column;align-items:center;justify-content:center;gap:4px;text-decoration:none}.mode-launch b{font-size:17px}.mode-launch span{font-size:12px;opacity:.78}.saved-grid{margin-top:12px}.saved-button{border:0;border-radius:18px;padding:14px 18px;background:linear-gradient(135deg,#f59e0b,#ef4444);color:#fff;font-weight:950;box-shadow:0 16px 34px rgba(239,68,68,.24);cursor:pointer;text-align:center;text-decoration:none}.saved-button:hover{transform:translateY(-1px);filter:saturate(1.05)}.saved-mini-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}.saved-mini-actions a{font-size:12px;font-weight:900;text-decoration:none;color:#4f46e5;background:#eef2ff;border:1px solid #c7d2fe;border-radius:999px;padding:7px 10px}
.flash-screen .study-deck{scroll-snap-type:x mandatory}.flash-premium-card{max-width:min(1040px,90vw);min-height:min(720px,calc(100vh - 170px));margin:auto;background:linear-gradient(150deg,rgba(255,255,255,.20),rgba(255,255,255,.08));border:1px solid rgba(255,255,255,.22);box-shadow:0 30px 90px rgba(21,11,89,.38), inset 0 1px 0 rgba(255,255,255,.25);position:relative;overflow:hidden}.flash-premium-card::before{content:"";position:absolute;inset:-35% -10% auto auto;width:65%;height:65%;background:radial-gradient(circle,rgba(255,255,255,.28),transparent 65%);pointer-events:none}.flash-game-layout{display:grid;grid-template-columns:.82fr 1.18fr;gap:22px;width:100%;align-items:stretch;min-height:430px}.flash-media-panel{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:18px;border-radius:30px;background:linear-gradient(135deg,rgba(255,255,255,.22),rgba(255,255,255,.07));border:1px solid rgba(255,255,255,.18);padding:22px}.flash-emoji-card{width:min(240px,34vw);height:min(240px,34vw);display:grid;place-items:center;border-radius:42px;font-size:clamp(82px,12vw,132px);background:linear-gradient(145deg,#fff,#e0f2fe 48%,#ddd6fe);box-shadow:0 28px 70px rgba(15,23,42,.25);transform:rotate(-2deg)}.flash-game-image{max-width:100%;max-height:260px;object-fit:contain;border-radius:28px;background:#fff;box-shadow:0 20px 50px rgba(0,0,0,.18)}.flash-caption{text-align:center;color:#fff;text-shadow:0 2px 6px rgba(0,0,0,.25)}.flash-caption b{display:block;font-size:20px}.flash-caption span{font-size:13px;opacity:.82}.flash-game-card{appearance:none;border:0;text-align:center;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:18px;border-radius:30px;padding:34px;cursor:pointer;background:linear-gradient(180deg,rgba(255,255,255,.96),rgba(239,246,255,.94));box-shadow:0 20px 60px rgba(0,0,0,.18);color:#101828;min-height:430px;max-height:calc(100vh - 320px);overflow:auto}.flash-game-card h1{font-size:clamp(30px,4.6vw,68px);line-height:1.04;margin:0;font-weight:1000;letter-spacing:-.04em}.flash-game-card .translated-line{font-size:.42em;line-height:1.2;margin-top:14px;color:#4f46e5;display:block}.flash-study-explanation{width:100%;text-align:left;background:#fff;border:1px solid #dbeafe;border-radius:24px;padding:18px 20px;box-shadow:0 12px 32px rgba(15,23,42,.1)}.flash-study-explanation strong{display:block;color:#2563eb;font-size:20px;margin-bottom:6px}.flash-study-explanation p{margin:4px 0;font-size:clamp(15px,1.5vw,19px);line-height:1.45;color:#0f172a}.flash-status-bar{margin-top:14px;padding:10px 16px;border-radius:18px;background:rgba(255,255,255,.16);color:#fff;font-weight:900;text-align:center}.flash-status-bar.active{background:rgba(16,185,129,.22);border:1px solid rgba(255,255,255,.22)}.flash-actions{position:relative!important;inset:auto!important;margin-top:16px;width:100%;display:flex!important;justify-content:center!important;flex-wrap:wrap;gap:10px}.flash-actions button{min-width:128px}.flash-finish-screen .finish-card{background:rgba(255,255,255,.95)}
.student-study-toolbar{right:auto;left:82px}.student-study-toolbar select{font-weight:900}
@media(max-width:860px){.topic-mode-grid{grid-template-columns:1fr}.study-session-pill{top:64px;font-size:12px;padding:8px 12px}.flash-premium-card{min-height:calc(100vh - 150px);max-width:94vw}.flash-game-layout{grid-template-columns:1fr;gap:12px;min-height:auto}.flash-media-panel{padding:14px;min-height:160px}.flash-emoji-card{width:132px;height:132px;border-radius:30px;font-size:78px}.flash-caption span{display:none}.flash-game-card{min-height:290px;max-height:none;padding:22px}.flash-game-card h1{font-size:clamp(26px,9vw,44px)}.flash-actions button{flex:1 1 42%;min-width:0}.student-study-toolbar{left:12px;right:auto;top:74px;max-width:calc(100vw - 24px)}}
@media(max-width:540px){.flash-actions button{flex-basis:100%}.flash-study-explanation{padding:14px}.study-session-pill{display:none}.flash-game-card h1{letter-spacing:-.025em}.flash-media-panel{display:none}}

/* Final fullscreen flashcard layout and professional top controls */
.student-study-toolbar {
  top: calc(env(safe-area-inset-top) + 14px);
  left: calc(env(safe-area-inset-left) + 82px);
  right: auto;
  min-height: 54px;
  gap: 12px;
  padding: 8px 12px;
  border-radius: 16px;
  background: rgba(12, 10, 35, .62);
}
.mini-switch-row,
.mini-lang-row {
  min-height: 36px;
}
.mini-lang-row select {
  min-width: 118px;
}
.study-ad-slot {
  top: calc(env(safe-area-inset-top) + 14px);
  right: calc(env(safe-area-inset-right) + 24px);
}
.study-session-pill {
  top: calc(env(safe-area-inset-top) + 82px);
}
.study-progress-line {
  top: calc(env(safe-area-inset-top) + 82px);
  left: calc(env(safe-area-inset-left) + 24px);
  right: calc(env(safe-area-inset-right) + 24px);
}
.flash-screen .study-deck,
.flash-screen .study-slide {
  height: 100dvh;
}
.flash-screen .study-slide {
  padding: calc(env(safe-area-inset-top) + 108px) clamp(12px, 2.2vw, 28px) calc(env(safe-area-inset-bottom) + 12px);
}
.flash-premium-card {
  width: min(1220px, 100%);
  max-width: 100%;
  height: min(820px, calc(100dvh - 124px));
  min-height: 0;
  border-radius: clamp(18px, 2.2vw, 28px);
}
.flash-game-layout {
  min-height: 0;
  height: 100%;
  grid-template-columns: minmax(220px, .72fr) minmax(0, 1.28fr);
}
.flash-game-card {
  min-height: 0;
  max-height: none;
  height: 100%;
  overflow: auto;
  overflow-wrap: anywhere;
}
.flash-game-card h1 {
  max-width: 100%;
}
.flash-status-bar {
  margin-top: 0;
}
.flash-actions {
  margin-top: 0;
}
.flash-actions button {
  min-width: 118px;
}
@media (max-width: 980px) {
  .study-ad-slot {
    width: min(260px, 36vw);
    height: 44px;
    top: calc(env(safe-area-inset-top) + 16px);
    right: 12px;
  }
  .student-study-toolbar {
    top: calc(env(safe-area-inset-top) + 14px);
    left: calc(env(safe-area-inset-left) + 68px);
    bottom: auto;
    max-width: calc(100vw - 352px);
  }
  .flash-screen .study-slide {
    padding-top: calc(env(safe-area-inset-top) + 104px);
  }
  .flash-game-layout {
    grid-template-columns: 1fr;
  }
  .flash-media-panel {
    min-height: 132px;
  }
}
@media (max-width: 720px) {
  .study-close {
    top: calc(env(safe-area-inset-top) + 10px);
    left: calc(env(safe-area-inset-left) + 10px);
    width: 44px;
    height: 44px;
  }
  .student-study-toolbar {
    left: calc(env(safe-area-inset-left) + 62px);
    right: auto;
    width: calc(100vw - 74px - env(safe-area-inset-left) - env(safe-area-inset-right));
    max-width: none;
    justify-content: space-between;
  }
  .study-ad-slot {
    top: calc(env(safe-area-inset-top) + 72px);
    right: 10px;
    left: auto;
    transform: none;
    width: min(190px, 44vw);
    opacity: .78;
  }
  .study-progress-line {
    top: calc(env(safe-area-inset-top) + 124px);
    left: 10px;
    right: 10px;
  }
  .flash-screen .study-slide {
    padding: calc(env(safe-area-inset-top) + 142px) 8px calc(env(safe-area-inset-bottom) + 8px);
  }
  .flash-premium-card {
    height: calc(100dvh - 152px);
    padding: 8px;
    gap: 6px;
  }
  .flash-game-card {
    padding: 18px 14px;
    gap: 12px;
  }
  .flash-actions {
    gap: 6px;
  }
  .flash-actions button {
    flex: 1 1 calc(50% - 6px);
    min-height: 40px;
    min-width: 0;
    padding: 8px 10px;
    font-size: 13px;
  }
}
@media (max-width: 430px) {
  .mini-lang-row select {
    min-width: 92px;
    max-width: 110px;
  }
  .flash-premium-card {
    height: calc(100dvh - 150px);
  }
  .flash-game-card h1 {
    font-size: clamp(24px, 8vw, 36px);
  }
  .flash-actions button {
    flex-basis: 100%;
  }
}

/* Launch-ready account, report, request, and ad controls */
.auth-card,
.account-panel,
.launch-settings {
  display: grid;
  gap: 1rem;
}
.google-login-slot {
  min-height: 44px;
  display: grid;
  align-items: center;
}
.auth-divider {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: .75rem;
  color: var(--muted);
  font-size: .82rem;
  font-weight: 900;
}
.auth-divider::before,
.auth-divider::after {
  content: "";
  height: 1px;
  background: var(--line);
}
.launch-modal {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: grid;
  place-items: center;
  padding: clamp(12px, 3vw, 28px);
  background: rgba(2, 6, 23, .64);
  backdrop-filter: blur(12px);
}
.launch-modal-card {
  position: relative;
  width: min(560px, 100%);
  max-height: min(760px, calc(100dvh - 32px));
  overflow: auto;
  display: grid;
  gap: .9rem;
  padding: clamp(1rem, 3vw, 1.5rem);
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--surface);
  color: var(--text);
  box-shadow: var(--shadow);
}
.modal-close {
  position: absolute;
  top: 10px;
  right: 10px;
  width: 38px;
  height: 38px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface-2);
  color: var(--text);
  font-size: 1.4rem;
  line-height: 1;
}
.report-button {
  white-space: nowrap;
}
.subscription-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.upgrade-mini {
  min-height: 34px;
  padding: 0 12px;
  border: 1px solid rgba(255,255,255,.25);
  border-radius: 999px;
  background: #fff;
  color: #1e1b4b;
  font-weight: 950;
}
.student-study-toolbar.free-access {
  border-style: dashed;
}
.student-study-toolbar select:disabled,
.student-study-toolbar input:disabled + i {
  opacity: .58;
  cursor: not-allowed;
}
.study-ad-slot.adsense-live {
  display: block;
  width: min(336px, 34vw);
  min-height: 50px;
  height: auto;
  padding: 0;
  border-style: solid;
  overflow: hidden;
  pointer-events: auto;
}
.study-ad-slot.adsense-live ins,
.study-ad-slot.adsense-live iframe {
  max-width: 100%;
}
@media (max-width: 720px) {
  .subscription-panel {
    align-items: stretch;
    flex-direction: column;
  }
  .report-button {
    flex: 1 1 100%;
  }
  .study-ad-slot.adsense-live {
    width: min(190px, 44vw);
  }
}

/* Final mobile study polish: compact footer icons, Kahoot grid, no duplicate progress bar */
@media (max-width: 760px) {
  .study-progress-line {
    display: none !important;
  }
  .study-slide {
    padding: calc(env(safe-area-inset-top) + 94px) 8px calc(env(safe-area-inset-bottom) + 8px) !important;
  }
  .flash-screen .study-slide {
    padding: calc(env(safe-area-inset-top) + 126px) 8px calc(env(safe-area-inset-bottom) + 8px) !important;
  }
  .study-card.kahoot-card,
  .flash-premium-card {
    height: calc(100dvh - 112px) !important;
    padding: 8px !important;
    gap: 6px !important;
    border-radius: 20px !important;
  }
  .flash-premium-card {
    height: calc(100dvh - 136px) !important;
  }
  .study-card-head.compact {
    min-height: 34px;
  }
  .study-content.kahoot-content {
    grid-template-rows: minmax(72px, 22%) auto minmax(0, 1fr) !important;
    gap: 6px !important;
    min-height: 0;
  }
  .study-card.kahoot-card.is-wrong .study-content.kahoot-content,
  .study-card.kahoot-card.is-correct .study-content.kahoot-content {
    padding-top: 28px !important;
  }
  .study-media {
    width: min(420px, 88%) !important;
    min-height: 70px !important;
  }
  .study-media.has-image .question-image {
    max-height: 22dvh !important;
  }
  .study-question {
    min-height: 58px !important;
    padding: 8px 10px !important;
    border-radius: 12px !important;
    font-size: clamp(1rem, 4.4vw, 1.45rem) !important;
    line-height: 1.08 !important;
  }
  .study-question .translated-line {
    margin-top: 5px;
  }
  .study-options.kahoot-options {
    display: grid !important;
    grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
    grid-auto-rows: minmax(96px, 1fr);
    gap: 8px !important;
    min-height: 0;
  }
  .study-option.kahoot-option {
    min-height: 96px !important;
    height: 100%;
    grid-template-columns: 26px minmax(0, 1fr) !important;
    align-content: center;
    border-radius: 10px !important;
    padding: 9px !important;
    font-size: clamp(.86rem, 3.5vw, 1.08rem) !important;
    box-shadow: inset 0 -5px 0 rgba(0,0,0,.22), 0 10px 18px rgba(0,0,0,.16) !important;
  }
  .option-shape {
    width: 24px !important;
    height: 24px !important;
    align-self: start;
    margin-top: 2px;
  }
  .option-label strong {
    -webkit-line-clamp: 4 !important;
  }
  .study-explanation-panel,
  .flash-study-explanation {
    max-height: 34dvh;
    overflow: auto;
    padding: 12px 14px !important;
    border-radius: 18px !important;
  }
  .study-explanation-panel strong,
  .flash-study-explanation strong {
    font-size: 1rem !important;
  }
  .study-explanation-panel p,
  .flash-study-explanation p {
    font-size: .94rem !important;
    line-height: 1.35 !important;
  }
  .translated-explanation {
    margin-top: 6px !important;
    padding-top: 6px !important;
  }
  .wrong-popup.compact-review,
  .wrong-popup {
    min-height: 0 !important;
    max-height: 118px !important;
    padding: 10px 12px !important;
    border-radius: 16px !important;
    overflow: hidden !important;
  }
  .wrong-popup.compact-review strong,
  .wrong-popup strong {
    font-size: 1rem !important;
  }
  .wrong-actions {
    display: flex !important;
    flex-wrap: nowrap !important;
    gap: 6px !important;
  }
  .study-bottom-actions.clean-actions,
  .study-bottom-actions.auto-note,
  .flash-actions {
    display: flex !important;
    flex-wrap: nowrap !important;
    align-items: center;
    justify-content: center !important;
    gap: 6px !important;
    width: 100%;
    margin-top: 0 !important;
    padding: 6px;
    border-radius: 18px;
    background: rgba(92, 24, 140, .32);
    border: 1px solid rgba(255,255,255,.12);
    backdrop-filter: blur(12px);
  }
  .study-bottom-actions.auto-note {
    flex-wrap: nowrap !important;
  }
  .study-bottom-actions.auto-note > span {
    display: none;
  }
  .study-bottom-actions.clean-actions button,
  .study-bottom-actions.auto-note button,
  .flash-actions button,
  .wrong-actions button {
    min-width: 0 !important;
    width: auto;
    flex: 0 1 46px !important;
    min-height: 44px !important;
    padding: 0 !important;
    border-radius: 14px !important;
    font-size: 0 !important;
    line-height: 1 !important;
    box-shadow: none !important;
    overflow: hidden;
  }
  .study-bottom-actions.clean-actions button::before,
  .study-bottom-actions.auto-note button::before,
  .flash-actions button::before,
  .wrong-actions button::before {
    display: inline-grid;
    place-items: center;
    width: 100%;
    font-size: 1.28rem;
    line-height: 1;
  }
  [data-mobile-icon="answer"]::before { content: "👁"; }
  [data-mobile-icon="dislike"]::before { content: "👎"; }
  [data-mobile-icon="like"]::before { content: "👍"; }
  [data-mobile-icon="love"]::before { content: "❤"; color: #fff; }
  [data-mobile-icon="report"]::before { content: "⚑"; }
  [data-mobile-icon="next"] {
    font-size: .98rem !important;
    font-weight: 1000 !important;
    letter-spacing: 0 !important;
    flex: 1 1 72px !important;
  }
  [data-mobile-icon="next"]::before {
    content: none !important;
  }
  .flash-status-bar {
    display: none !important;
  }
  .flash-game-layout {
    min-height: 0 !important;
    height: 100% !important;
  }
  .flash-game-card {
    padding: 14px 12px !important;
    gap: 10px !important;
  }
  .flash-game-card h1 {
    font-size: clamp(1.45rem, 7vw, 2.15rem) !important;
  }
}
@media (max-width: 430px) {
  .study-options.kahoot-options {
    grid-auto-rows: minmax(86px, 1fr);
    gap: 7px !important;
  }
  .study-option.kahoot-option {
    min-height: 86px !important;
    font-size: clamp(.78rem, 3.25vw, .98rem) !important;
  }
  .study-bottom-actions.clean-actions,
  .flash-actions {
    gap: 5px !important;
    padding: 5px;
  }
  .study-bottom-actions.clean-actions button,
  .study-bottom-actions.auto-note button,
  .flash-actions button,
  .wrong-actions button {
    min-height: 40px !important;
    border-radius: 12px !important;
    flex-basis: 40px !important;
  }
  [data-mobile-icon="next"] { flex-basis: 62px !important; }
  .study-explanation-panel,
  .flash-study-explanation {
    max-height: 30dvh;
  }
}