* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: sans-serif;
}

section {
  
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
  padding: 20px;
}

.header {
  background-color: #2c3e50;
  color: white;
  padding: 20px 30px;
}


.container {
  text-align: center;
  width: 100%;
  max-width: 360px;
}

.tabs {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
  gap: 10px;
}

.tab {
  padding: 10px 20px;
  border: none;
  background: #ddd;
  font-size: 1rem;
  cursor: pointer;
  border-radius: 5px;
}

.tab.active {
  background-color: #4285f4;
  color: white;
}

.tab:hover {

  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

/* 🃏 Flashcard Flip Effect */
.flashcard-wrapper {
  perspective: 1000px;
}

.flashcard {
  width: 100%;
  height: 300px;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.6s;
  cursor: pointer;
}
.flashcard:hover{
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}
.flashcard.flipped {
  transform: rotateY(180deg);
}

.front, .back {
  position: absolute;
  width: 100%;
  height: 100%;
  background: white;
  border: 2px solid #ccc;
  border-radius: 10px;
  padding: 30px;
  backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  font-size: 2.2rem;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.back {
  transform: rotateY(180deg);
}

.voice-btn {
  margin-top: 15px;
  font-size: 2.2rem;
  cursor: pointer;
  background: none;
  border: none;
}
.voice-btn:hover{

  font-size: 3rem;
}


.buttons {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 20px;
}

@media screen and (max-width: 500px) {
  .flashcard {
    height: 380px;
  }

  .front, .back {
    font-size: 1.1rem;
  }
}


/*..... prev/next-button......*/
.prev-btn, .next-btn {

  font-size: 18px;
  letter-spacing: 2px;
  text-transform: uppercase;
  display: inline-block;
  text-align: center;
  font-weight: bold;
  padding: 0.7em 2em;
  border: 3px solid #ff0072;
  border-radius: 2px;
  position: relative;
  box-shadow: 0 2px 10px rgba(0,0,0,0.16);
  color: #ff0072;
  text-decoration: none;
  transition: 0.3s ease all;
  z-index:1;
}
.prev-btn:before, .next-btn:before{

  transition: 0.5 all ease;
  position: absolute;
  top: 0;
  left: 50%;
  right: 50%;
  bottom: 0;
  opacity: 0;
  content: '';
  background-color: #ff0072;
  z-index: -1;
}
.prev-btn:hover, .prev-btn:focus{

  color: white;
}
.prev-btn:hover::before, .prev-btn:focus::before {

  transition: o.5s all ease;
  left: 0;
  right: 0;
  opacity: 1;
}
.prev-btn:active {

  transform: scale(0.9);
}
/*,,,*/

.next-btn:hover, .next-btn:focus{

  color: white;
}
.next-btn:hover::before, .next-btn:focus::before {

  transition: o.5s all ease;
  left: 0;
  right: 0;
  opacity: 1;
}
.next-btn:active {

  transform: scale(0.9);
}