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

body {
  background: #020617;
  color: #fff;
  font-family: "Inter", sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  margin: 0;
  text-align: center;
  overflow: hidden;
  user-select: none;
}

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

.bg-glow {
  position: fixed;
  inset: 0;
  background: radial-gradient(
    ellipse 80% 60% at 50% 40%,
    rgba(30, 58, 138, 0.27) 0%,
    transparent 70%
  );
  z-index: 0;
  pointer-events: none;
}

.back-home {
  position: fixed;
  top: 20px;
  left: 24px;
  font-size: 0.85rem;
  color: #475569;
  text-decoration: none;
  transition: color 0.2s;
  z-index: 10;
}

.back-home:hover {
  color: #fff;
}

.container {
  position: relative;
  z-index: 1;
  padding: 40px 24px;
  max-width: 560px;
  width: 100%;
}

h1 {
  font-family: "Syne", sans-serif;
  font-size: clamp(2rem, 8vw, 3rem);
  font-weight: 900;
  margin: 0 0 6px;
  letter-spacing: -2px;
}

.subtitle {
  font-size: 0.95rem;
  color: #64748b;
  margin-bottom: 28px;
}

.stats-row {
  display: flex;
  gap: 24px;
  justify-content: center;
  margin-bottom: 20px;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
}

.stat-val {
  font-family: "Syne", sans-serif;
  font-size: 1.8rem;
  font-weight: 900;
  color: #f8fafc;
}

.stat-label {
  font-size: 0.7rem;
  color: #475569;
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

.timer-wrap {
  width: 100%;
  height: 8px;
  background: rgba(30, 58, 138, 0.25);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 28px;
}

.timer-bar {
  height: 100%;
  border-radius: 999px;
  background: #3b82f6;
  transition:
    width 0.1s linear,
    background 0.3s;
}

.timer-bar.warn {
  background: #fbbf24;
}

.timer-bar.danger {
  background: #ef4444;
}

.question-display {
  font-family: "Syne", sans-serif;
  font-size: clamp(2.5rem, 12vw, 5rem);
  font-weight: 900;
  line-height: 1;
  margin-bottom: 28px;
  color: #f8fafc;
  letter-spacing: -2px;
}

.answer-input {
  width: 100%;
  padding: 16px 20px;
  background: rgba(15, 23, 42, 0.7);
  border: 1.5px solid rgba(51, 65, 85, 0.7);
  border-radius: 14px;
  color: #fff;
  font-family: "Syne", sans-serif;
  font-size: 1.8rem;
  font-weight: 700;
  text-align: center;
  outline: none;
  letter-spacing: 2px;
  transition:
    border-color 0.2s,
    background 0.2s;
  margin-bottom: 16px;
}

.answer-input:focus {
  border-color: rgba(96, 165, 250, 0.5);
  background: rgba(15, 23, 42, 0.9);
}

.answer-input.correct {
  border-color: #10b981;
  background: rgba(16, 185, 129, 0.1);
  animation: inputPop 0.2s ease;
}

.answer-input.wrong {
  border-color: #ef4444;
  background: rgba(239, 68, 68, 0.1);
  animation: inputShake 0.3s ease;
}

@keyframes inputPop {
  0%,
  100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.03);
  }
}

@keyframes inputShake {
  0%,
  100% {
    transform: translateX(0);
  }
  25% {
    transform: translateX(-6px);
  }
  75% {
    transform: translateX(6px);
  }
}

.feedback {
  font-size: 0.9rem;
  min-height: 22px;
  color: #475569;
  transition: color 0.2s;
}

.feedback.good {
  color: #10b981;
}

.feedback.bad {
  color: #f87171;
}

.difficulty-row {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-bottom: 24px;
}

.diff-btn {
  padding: 7px 18px;
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  border: 1px solid rgba(51, 65, 85, 0.6);
  background: transparent;
  color: #475569;
  cursor: pointer;
  transition: all 0.2s;
}

.diff-btn.active {
  background: rgba(96, 165, 250, 0.15);
  border-color: rgba(96, 165, 250, 0.4);
  color: #60a5fa;
}

.gameover {
  position: fixed;
  inset: 0;
  background: rgba(2, 6, 23, 0.92);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 50;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s;
  backdrop-filter: blur(8px);
}

.gameover.show {
  opacity: 1;
  pointer-events: all;
}

.go-emoji {
  font-size: 4rem;
  margin-bottom: 12px;
}

.go-title {
  font-family: "Syne", sans-serif;
  font-size: clamp(1.8rem, 7vw, 2.8rem);
  font-weight: 900;
  margin: 0 0 8px;
}

.go-sub {
  color: #64748b;
  font-size: 1rem;
  margin-bottom: 28px;
}

.go-sub span {
  color: #60a5fa;
  font-weight: 700;
}

.go-btn {
  padding: 13px 36px;
  background: rgba(37, 99, 235, 0.3);
  border: 1.5px solid rgba(96, 165, 250, 0.45);
  border-radius: 999px;
  color: #fff;
  font-family: "Syne", sans-serif;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.2s;
}

.go-btn:hover {
  background: rgba(37, 99, 235, 0.5);
}