/* =========================
   GLOBAL SCROLL
========================= */
html {
  scroll-behavior: smooth;
}

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

main {
  font-family: 'Inter', sans-serif;
  color: #222;
  line-height: 1.6;
  background: url("../imgs/index_bg.png") center / cover no-repeat fixed;
}

main::before {
  content: "";
  position: fixed;
  inset: 0;
  background: rgba(120, 120, 120, 0.35); /* grey tint */
  z-index: -1;
}

/* =========================
   BACK BUTTON
========================= */

.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;

  margin-bottom: 20px;
  margin-left:40px;

  padding: 8px 16px;

  background: rgba(0, 0, 0, 0.5);
  color: white;

  border: none;
  border-radius: 6px;

  font-size: 16px;
  font-weight: 600;

  cursor: pointer;

  transition: background 0.25s ease, transform 0.2s ease;
}

.back-btn:hover {
  background: rgba(0, 0, 0, 0.8);
  transform: translateY(-1px);
}

/* =========================
   CERTIFICATION SECTION
========================= */
.cert-section {
  padding: 120px 50px;
  color:white;
  background:rgba(0,0,0,.55);
}

.section-title {
  text-align: center;
  font-size: 32px;
  margin-bottom: 50px;
}

.cert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 28px;
}

.cert-card {
  background: #fff;
  color: black;
  border: 1px solid #e5e5e5;
  border-radius: 16px;
  padding: 20px;
  transition: 0.3s ease;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.cert-card:hover {
  transform: translateY(-6px);
}

.cert-images {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
  gap: 8px;
  margin-bottom: 18px;
  align-items: start;
}

.cert-thumb {
  width: 100%;
  height: 180px;
  object-fit: contain;
  object-position: center;
  border-radius: 10px;
  cursor: pointer;
  transition: 0.2s ease;
  background: #f5f5f5;
  padding: 8px;
}

.cert-thumb:hover {
  opacity: 0.9;
}

.cert-info h3 {
  font-size: 20px;
  margin-bottom: 6px;
}

.cert-info p {
  font-size: 14px;
  color: #666;
}

/* =========================
   LIGHTBOX
========================= */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.85);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: 0.3s ease;
  z-index: 999;
}

.lightbox.active {
  opacity: 1;
  pointer-events: auto;
}

.lightbox-img {
  max-width: 90%;
  max-height: 85%;
  border-radius: 12px;
  transform: scale(1);
  transition: transform 0.2s ease;
  cursor: zoom-in;
}

.lightbox-img.zoomed {
  transform: scale(1.8);
  cursor: zoom-out;
}

/* NAV BUTTONS */
.lightbox-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  font-size: 32px;
  color: white;
  padding: 10px;
  cursor: pointer;
  user-select: none;
}

.lightbox-nav.prev { left: 20px; }
.lightbox-nav.next { right: 20px; }

.lightbox-close {
  position: absolute;
  top: 20px;
  right: 26px;
  font-size: 32px;
  color: white;
  cursor: pointer;
}