/* ===========================
   RESET & BASE
=========================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background: linear-gradient(180deg, #eaf0ff, #f7f9ff);
  color: #222;
  overflow-x: hidden; /* Prevent horizontal scroll */
}

/* ===========================
   BOOKS / KNOWLEDGE CARDS
=========================== */
.books-section {
  max-width: 100%; /* Full width */
  padding: 20px 15px; /* Proper left-right space */
  text-align: center;
}

.books-section h2 {
  font-size: 26px;
  color: #0288d1;
  margin-bottom: 25px;
  font-weight: 600;
}

.books-container {
  display: flex;
  flex-direction: column; /* vertical stack */
  gap: 20px;
  align-items: center;
}

/* ===========================
   CARD STYLE
=========================== */
.book-card {
  width: 100%;         /* Full width of container */
  max-width: 520px;    /* Prevent too wide on large screens */
  background: #ffffffee;
  border-radius: 28px;
  padding: 20px;
  box-shadow: 0 12px 28px rgba(0,0,0,0.12);
  text-align: left;
  transition: 0.3s;
}

.book-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 0 28px #81d4fa;
}

.book-card h3 {
  color: #0288d1;
  margin-bottom: 8px;
  font-weight: 600;
}

.book-card p {
  font-size: 15px;
  line-height: 1.6;
  color: #444;
}

/* ===========================
   GLOW BUTTON
=========================== */
.glow-btn {
  display: inline-block;
  margin-top: 12px;
  padding: 10px 24px;
  background: #D9F0FF;
  color: #222;
  border-radius: 28px;
  text-decoration: none;
  box-shadow: 0 0 12px #81d4fa;
  transition: 0.3s;
  animation: breathe 2.5s infinite;
}

.glow-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 22px #4fc3f7;
}

/* Glow animation */
@keyframes breathe {
  0% { box-shadow: 0 0 12px #81d4fa; }
  50% { box-shadow: 0 0 26px #4fc3f7; }
  100% { box-shadow: 0 0 12px #81d4fa; }
}

/* ===========================
   MOBILE RESPONSIVE
=========================== */
@media (max-width: 600px) {
  .books-section {
    padding: 15px 10px;
  }
  
  .book-card {
    width: 100%; /* Fit exactly in mobile screen */
  text-align: center;
    padding: 18px;
  }

  .glow-btn {
  width: fit-content;     /* ⭐ key line */
  max-width: 100%;
  display: inline-block;
  margin-left: auto;
  margin-right: auto;
}

  .books-section h2 {
    font-size: 22px;
  }
}