@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@500&display=swap');

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body, html {
  height: 100%;
  font-family: 'Poppins', sans-serif;
  overflow: hidden;
}

/* HERO CONTAINER */
.hero {
  position: relative;
  height: 100vh;
  width: 100%;
  overflow: hidden;
  text-align: center;

  /* center content vertically & horizontally */
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

/* FULL‑SCREEN BACKGROUND IMAGE */
.hero-bg-img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.6;
  z-index: 0;
  pointer-events: none;
}

/* ANIMATED GRADIENT OVERLAY */
.hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    -45deg,
    #c3d9d8,
    #9bdd9d,
    #c3f5c8,
    #bbeabd
  );
  background-size: 400% 400%;
  animation: gradientMove 5s ease infinite;
  opacity: 0.5;
  z-index: 1;
}

/* GRADIENT ANIMATION */
@keyframes gradientMove {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* BRING HERO CONTENT ABOVE LAYERS */
.top-right-buttons,
.hero-content {
  position: relative;
  z-index: 2;
}

/* LOGIN / REGISTER BUTTONS */
.top-right-buttons {
  position: absolute;
  top: 30px;
  right: 40px;
}
.top-right-buttons a {
  margin-left: 15px;
  padding: 10px 20px;
  text-decoration: none;
  border-radius: 6px;
  font-weight: bold;
  transition: 0.3s;
}
.btn {
  background-color: transparent;
  border: 2px solid #388e3c;
  color: #388e3c;
}
.btn:hover {
  background-color: #388e3c;
  color: white;
}
.register {
  background-color: #2e7d32;
  border: none;
  color: white;
}
.register:hover {
  background-color: #66bb6a;
}

/* HERO TEXT BLOCK */
.hero-content {
  max-width: 700px;
  margin: 0 auto;
  padding: 20px;
  color: #1b5e20;
}
.logo {
  font-size: 3rem;
  color: #2e7d32;
  margin-bottom: 20px;
  text-shadow: 1px 1px #a5d6a7;
}
.hero-content h2 {
  font-size: 2rem;
  margin-bottom: 10px;
}
.hero-content p {
  font-size: 1.2rem;
  color: #33691e;
}

/* FLASHCARD GRID */
.category-cards {
  display: flex;
  justify-content: space-between;
  align-items: stretch;
  flex-wrap: nowrap;
  width: 90%;
  max-width: 1200px;
  margin: 0 auto 40px;
  gap: 40px;
}

/* FLASHCARD STYLING */
.card {
  width: 350px;
  height: 400px;
  perspective: 1200px;
  cursor: default;
}
.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s;
  transform-style: preserve-3d;
  border-radius: 12px;
}
.card:hover .card-inner,
.card:focus .card-inner {
  transform: rotateY(180deg);
}
.card-front,
.card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  border-radius: 12px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
  padding: 20px;
  color: #1b5e20;
  background: #b9efbf;
}
.card-front h2 {
  margin-bottom: 8px;
  font-size: 1.6rem;
}
.card-front p {
  font-size: 1.6rem;
  opacity: 0.8;
}
.card-back {
  transform: rotateY(180deg);
  background: #dbfae0;
}
.card-back p {
  font-size: 0.95rem;
  text-align: center;
  margin-bottom: 12px;
}
.start-btn {
  display: inline-block;
  padding: 8px 16px;
  background-color: #66bb6a;
  color: white;
  border-radius: 6px;
  font-weight: bold;
  text-decoration: none;
  cursor: pointer;
  z-index: 3;
}
.start-btn:hover {
  background-color: #57a05a;
}

/* ENSURE FLASHCARDS ABOVE GRADIENT */
.dashboard, .category-cards, .card {
  position: relative;
  z-index: 2;
}

/* DASHBOARD TITLE STYLING */
.dashboard h1 {
  font-size: 4rem;
  text-align: center;
  margin-bottom: 60px;
  color: #161c17;
  font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande',
    'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
}

/* DASHBOARD ANIMATED GRADIENT BACKGROUND */
.dashboard {
  position: relative;
  min-height: 100vh;
  padding: 60px 20px 40px;
  text-align: center;
  background: linear-gradient(
    -45deg,
    #d8e6ef,
    #9bdd9d,
    #b9efbf,
    #c5fac7
  );
  background-size: 400% 400%;
  animation: gradientMove 4s ease infinite;
}

/* TYPEWRITER EFFECT FOR DASHBOARD TITLE */
#dashboard-title {
  display: inline-block;
  font-size: 4rem;
  color: #ffffff;
  white-space: nowrap;
  overflow: hidden;
  border-right: 0.15em solid #2e7d32;
  margin-bottom: 60px;
  animation: blinkCursor 1s step-end infinite;
}

/* BLINKING CURSOR */
@keyframes blinkCursor {
  from,
  to {
    border-color: transparent;
  }
  50% {
    border-color: #2e7d32;

  }
}

/* ── DASHBOARD BACK BUTTON ──────────────────────────────────────── */
.dashboard {
    position: relative;  /* ensure the button can be absolutely positioned */
  }
  
  .back-button {
    position: absolute;
    top: 20px;           /* adjust distance from top */
    left: 20px;          /* adjust distance from left */
    z-index: 3;          /* above the gradient & content */
  }
  
  .btn-back {
    display: inline-block;
    padding: 8px 16px;
    font-size: 1rem;
    font-weight: 500;
    color: #2E7D32;                /* same accent green */
    background: transparent;
    border: 2px solid #2E7D32;     /* same accent green */
    border-radius: 6px;
    text-decoration: none;
    transition: background 0.3s, color 0.3s;
  }
  
  .btn-back:hover {
    background: #2E7D32;           /* fill with accent on hover */
    color: white;                  /* white text on hover */
  }