/* ===== RESET + VARIÁVEIS ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

:root {
  --deep-blue: #010b1a;
  --glow-cyan: #00f2ff;
  --glow-teal: #00c2d4;
  --text-light: #e6f7ff;
  --text-muted: #8bbcd9;
  --card-bg: rgba(6, 25, 45, 0.75);
  --card-border: rgba(0, 242, 255, 0.25);
  --shadow-glow: 0 0 30px rgba(0, 242, 255, 0.15);
  --transition: all 0.3s cubic-bezier(0.2, 0.9, 0.4, 1.1);
}

body {
  font-family: 'Inter', sans-serif;
  background: radial-gradient(ellipse at 30% 20%, #021e30, var(--deep-blue) 80%);
  color: var(--text-light);
  line-height: 1.5;
  min-height: 100vh;
  padding: 40px 20px;
}

.page-container {
  max-width: 1300px;
  margin: 0 auto;
}

/* ===== HEADER ===== */
.page-header {
  text-align: center;
  margin-bottom: 48px;
}

.back-home {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(0, 242, 255, 0.1);
  border: 1px solid var(--glow-cyan);
  border-radius: 40px;
  padding: 8px 20px;
  color: var(--glow-cyan);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
  margin-bottom: 24px;
}

.back-home:hover {
  background: var(--glow-cyan);
  color: #001427;
  transform: translateY(-2px);
}

.page-header h1 {
  font-size: clamp(2rem, 6vw, 2.8rem);
  background: linear-gradient(135deg, #fff, var(--glow-cyan));
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  margin-bottom: 12px;
}

.page-header p {
  color: var(--text-muted);
  font-size: 1.1rem;
}

/* ===== FLASHCARDS GRID ===== */
.flashcards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 30px;
  margin-bottom: 60px;
}

/* Estilo base do flashcard */
.flashcard {
  background: transparent;
  perspective: 1500px;
  height: 280px;
  cursor: pointer;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.6s cubic-bezier(0.23, 1, 0.32, 1);
  transform-style: preserve-3d;
  border-radius: 28px;
  box-shadow: 0 15px 30px rgba(0,0,0,0.3);
}

.flashcard.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

/* Frente e verso comuns */
.flashcard-front, .flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 28px;
  padding: 24px 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 12px;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  box-shadow: var(--shadow-glow);
}

/* Frente */
.flashcard-front {
  transform: rotateY(0deg);
}

.flashcard-front i {
  font-size: 48px;
  color: var(--glow-cyan);
  margin-bottom: 10px;
}

.flashcard-front h3 {
  font-size: 1.5rem;
  font-weight: 600;
}

.hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 20px;
  font-style: italic;
}

/* Verso */
.flashcard-back {
  transform: rotateY(180deg);
  text-align: center;
  justify-content: center;
}

.flashcard-back i {
  font-size: 40px;
  color: var(--glow-teal);
  margin-bottom: 15px;
}

.flashcard-back p {
  font-size: 0.95rem;
  line-height: 1.5;
  color: var(--text-light);
}

.flashcard-back strong {
  color: var(--glow-cyan);
}

/* Botão extra */
.extra-action {
  text-align: center;
  margin: 20px 0 40px;
}

.play-more {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: linear-gradient(105deg, var(--glow-cyan), var(--glow-teal));
  padding: 14px 32px;
  border-radius: 50px;
  font-weight: 700;
  font-size: 1.1rem;
  color: #001a2a;
  text-decoration: none;
  transition: var(--transition);
  box-shadow: 0 4px 15px rgba(0,242,255,0.3);
}

.play-more:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 25px rgba(0,242,255,0.5);
}

/* Footer */
.page-footer {
  text-align: center;
  padding: 32px 0 20px;
  border-top: 1px solid rgba(0, 242, 255, 0.2);
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Responsividade */
@media (max-width: 680px) {
  .flashcards-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .flashcard {
    height: 260px;
  }
  .page-header {
    margin-bottom: 32px;
  }
}