:root {
  /* Computer Vocabulary Challenge theme: Modern Technology, Cyber Blue, Glassmorphism */
  color-scheme: dark;
  --bg: #071226;
  --panel: rgba(255, 255, 255, .12);
  --panel-strong: rgba(255, 255, 255, .18);
  --line: rgba(255, 255, 255, .22);
  --text: #f4fbff;
  --muted: rgba(244, 251, 255, .74);
  --blue: #3388ff;
  --cyan: #4af6ff;
  --purple: #8b6cff;
  --pink: #ff67b3;
  --gold: #ffd66b;
  --green: #36e6a4;
  --red: #ff5e7a;
  --shadow: 0 28px 80px rgba(0, 0, 0, .36);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Prompt", "Sarabun", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 18% 18%, rgba(74, 246, 255, .24), transparent 28%),
    radial-gradient(circle at 86% 12%, rgba(139, 108, 255, .28), transparent 30%),
    radial-gradient(circle at 50% 100%, rgba(255, 103, 179, .18), transparent 34%),
    linear-gradient(135deg, #071226 0%, #0b2b5a 48%, #130c38 100%);
  overflow-x: hidden;
}

body.light-mode {
  color-scheme: light;
  --bg: #eef7ff;
  --panel: rgba(255, 255, 255, .72);
  --panel-strong: rgba(255, 255, 255, .9);
  --line: rgba(20, 61, 111, .18);
  --text: #0b2447;
  --muted: rgba(11, 36, 71, .72);
  --shadow: 0 26px 70px rgba(55, 89, 140, .18);
  background:
    radial-gradient(circle at 18% 18%, rgba(74, 246, 255, .32), transparent 28%),
    radial-gradient(circle at 86% 12%, rgba(139, 108, 255, .24), transparent 30%),
    linear-gradient(135deg, #f7fcff 0%, #e8f4ff 54%, #f8f0ff 100%);
}

button,
select,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.game-shell {
  position: relative;
  min-height: 100vh;
}

.screen {
  display: none;
  min-height: 100vh;
  padding: clamp(18px, 3vw, 34px);
  animation: fadeSlide .42s ease both;
}

.screen.is-active {
  display: block;
}

@keyframes fadeSlide {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

.topline,
.hud {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  max-width: 1180px;
  margin: 0 auto;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--panel);
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow);
}

.brand-link {
  color: var(--text);
  text-decoration: none;
  font-weight: 900;
}

.quick-toggles {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.quick-toggles button,
.btn {
  min-height: 46px;
  padding: 0 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  color: var(--text);
  background: var(--panel-strong);
  font-weight: 900;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}

.quick-toggles button:hover,
.btn:hover,
.answer-btn:hover,
.memory-card:hover,
.match-card:hover {
  transform: translateY(-3px);
}

.btn.primary {
  border: 0;
  color: #05152f;
  background: linear-gradient(135deg, var(--cyan), var(--blue));
  box-shadow: 0 16px 34px rgba(51, 136, 255, .32);
}

.btn.ghost {
  background: rgba(255,255,255,.1);
}

.btn.tiny {
  min-height: 40px;
  padding-inline: 14px;
}

.tech-orb {
  position: fixed;
  width: 280px;
  height: 280px;
  border-radius: 999px;
  filter: blur(18px);
  opacity: .45;
  pointer-events: none;
  animation: floatOrb 9s ease-in-out infinite;
}

.orb-one {
  left: -80px;
  top: 100px;
  background: var(--cyan);
}

.orb-two {
  right: -90px;
  bottom: 40px;
  background: var(--purple);
  animation-delay: -4s;
}

@keyframes floatOrb {
  0%, 100% { transform: translate3d(0,0,0) scale(1); }
  50% { transform: translate3d(40px,-35px,0) scale(1.15); }
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 430px);
  gap: clamp(22px, 4vw, 54px);
  align-items: center;
  max-width: 1180px;
  margin: clamp(34px, 7vw, 88px) auto 0;
}

.eyebrow {
  display: inline-flex;
  padding: 8px 13px;
  border: 1px solid rgba(74, 246, 255, .42);
  border-radius: 999px;
  color: var(--cyan);
  background: rgba(74, 246, 255, .12);
  font-size: 14px;
  font-weight: 1000;
  letter-spacing: .03em;
}

h1 {
  margin: 18px 0 16px;
  max-width: 820px;
  font-size: clamp(48px, 8vw, 96px);
  line-height: .96;
  letter-spacing: -.055em;
}

.hero-copy p {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
  font-size: clamp(19px, 2vw, 25px);
  line-height: 1.75;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.launch-card,
.question-card,
.result-card,
.home-panels article,
.modal-card {
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: 34px;
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow);
}

.launch-card {
  display: grid;
  gap: 16px;
  padding: 20px;
}

.launch-card img {
  width: 100%;
  border-radius: 24px;
  border: 1px solid var(--line);
  background: #081b37;
}

.launch-card label,
.save-score label {
  display: grid;
  gap: 8px;
  color: var(--muted);
  font-weight: 900;
}

.launch-card select,
.save-score input {
  min-height: 52px;
  width: 100%;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 16px;
  color: var(--text);
  background: rgba(0,0,0,.18);
  outline: none;
}

body.light-mode .launch-card select,
body.light-mode .save-score input {
  background: #fff;
}

.mini-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.mini-stats span,
.mode-pill,
.badge {
  padding: 8px 11px;
  border-radius: 999px;
  color: #061631;
  background: linear-gradient(135deg, var(--gold), #fff2aa);
  font-size: 14px;
  font-weight: 1000;
}

.home-panels {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  max-width: 1180px;
  margin: 24px auto 0;
}

.home-panels article {
  padding: 22px;
}

.home-panels h2 {
  margin: 0 0 12px;
}

.home-panels ul {
  margin: 0;
  padding-left: 24px;
  color: var(--muted);
  line-height: 1.8;
}

.play-screen {
  display: none;
  max-width: 1180px;
  margin: 0 auto;
}

.play-screen.is-active {
  display: block;
}

.hud {
  position: sticky;
  top: 12px;
  z-index: 5;
}

.hud-item {
  min-width: 92px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255,255,255,.08);
  text-align: center;
}

.hud-item small {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
}

.hud-item strong {
  display: block;
  font-size: 24px;
}

.hearts {
  color: var(--red);
  font-size: 25px;
  letter-spacing: 2px;
}

.progress-wrap {
  max-width: 1180px;
  margin: 18px auto;
  color: var(--muted);
  font-weight: 900;
}

.progress-bar {
  height: 12px;
  margin-top: 8px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255,255,255,.12);
}

.progress-bar i {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--cyan), var(--purple), var(--pink));
  transition: width .35s ease;
}

.question-card {
  position: relative;
  max-width: 980px;
  margin: 0 auto;
  padding: clamp(22px, 4vw, 38px);
  overflow: hidden;
}

.word-visual {
  display: grid;
  place-items: center;
  width: 112px;
  height: 112px;
  margin: 18px auto 12px;
  border: 1px solid rgba(74, 246, 255, .36);
  border-radius: 34px;
  background: radial-gradient(circle at 30% 20%, rgba(74,246,255,.28), rgba(139,108,255,.18));
  font-size: 58px;
  animation: cardPulse 2.6s ease-in-out infinite;
}

@keyframes cardPulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.04); }
}

.question-card h2 {
  margin: 0;
  text-align: center;
  font-size: clamp(42px, 7vw, 76px);
  line-height: 1.05;
}

.question-card > p {
  margin: 10px auto 18px;
  max-width: 720px;
  color: var(--muted);
  text-align: center;
  font-size: 20px;
  line-height: 1.6;
}

.speak-btn {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 48px;
  margin: 0 auto 20px;
  padding: 0 18px;
  border: 1px solid rgba(74,246,255,.32);
  border-radius: 999px;
  color: var(--text);
  background: rgba(74,246,255,.12);
  font-weight: 900;
}

.challenge-area {
  display: grid;
  gap: 12px;
}

.answers {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.answer-btn,
.match-card,
.memory-card {
  min-height: 66px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 20px;
  color: var(--text);
  background: rgba(255,255,255,.1);
  font-weight: 900;
  text-align: left;
  box-shadow: 0 12px 28px rgba(0,0,0,.14);
}

.answer-btn.correct,
.match-card.correct,
.memory-card.matched {
  border-color: rgba(54,230,164,.7);
  background: rgba(54,230,164,.18);
}

.answer-btn.wrong,
.match-card.wrong {
  border-color: rgba(255,94,122,.8);
  background: rgba(255,94,122,.18);
}

.match-board {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.match-column {
  display: grid;
  gap: 10px;
}

.match-card.selected {
  border-color: var(--gold);
  background: rgba(255,214,107,.18);
}

.memory-board {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.memory-card {
  min-height: 94px;
  display: grid;
  place-items: center;
  text-align: center;
  background: linear-gradient(135deg, rgba(51,136,255,.2), rgba(139,108,255,.16));
}

.memory-card:not(.flipped):not(.matched) {
  color: transparent;
}

.memory-card:not(.flipped):not(.matched)::before {
  content: "?";
  color: var(--cyan);
  font-size: 36px;
}

.feedback {
  min-height: 44px;
  margin-top: 16px;
  text-align: center;
  font-size: 22px;
  font-weight: 1000;
}

.feedback.good { color: var(--green); }
.feedback.bad { color: var(--red); }

.next-btn {
  display: flex;
  justify-content: center;
  margin: 10px auto 0;
}

.result-screen {
  display: none;
  place-items: center;
}

.result-screen.is-active {
  display: grid;
}

.result-card {
  width: min(940px, 100%);
  padding: clamp(22px, 4vw, 42px);
}

.result-card h2 {
  margin: 14px 0;
  font-size: clamp(36px, 6vw, 70px);
}

.grade-badge {
  display: inline-flex;
  padding: 10px 18px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--green), var(--cyan));
  color: #05152f;
  font-size: 22px;
  font-weight: 1000;
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 22px 0;
}

.summary-grid div {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: rgba(255,255,255,.08);
}

.summary-grid small {
  display: block;
  color: var(--muted);
  font-weight: 900;
}

.summary-grid strong {
  display: block;
  margin-top: 4px;
  font-size: 30px;
}

.badges {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  margin: 16px 0;
}

.save-score {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  align-items: end;
  margin: 20px 0;
}

.leaderboard {
  margin-top: 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: rgba(255,255,255,.08);
}

.leaderboard h3 {
  margin: 0 0 12px;
}

.leaderboard ol {
  margin: 0;
  padding-left: 24px;
  line-height: 1.8;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(3, 12, 26, .68);
  backdrop-filter: blur(8px);
}

.modal[hidden] { display: none; }

.modal-card {
  position: relative;
  width: min(720px, 100%);
  padding: 28px;
}

.modal-close {
  position: absolute;
  right: 16px;
  top: 16px;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text);
  background: var(--panel-strong);
  font-size: 28px;
}

#confettiCanvas {
  position: fixed;
  inset: 0;
  z-index: 30;
  pointer-events: none;
}

@media (max-width: 900px) {
  .hero-grid,
  .home-panels,
  .match-board {
    grid-template-columns: 1fr;
  }

  .hud {
    flex-wrap: wrap;
  }

  .hud-item {
    flex: 1 1 110px;
  }

  .memory-board {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .screen {
    padding: 12px;
  }

  h1 {
    font-size: clamp(42px, 15vw, 64px);
  }

  .answers,
  .summary-grid,
  .save-score {
    grid-template-columns: 1fr;
  }

  .memory-board {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}