body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f5f6f7;
}

/* HEADER */
.header {
  background: #0B2545;
  color: white;
  padding: 15px 25px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
}

.logo {
  display: flex;
  align-items: center;
  font-weight: bold;
  font-size: 16px;
}
.logo img {
  height: 40px;
  margin-right: 10px;
}

.nav-links {
  display: flex;
  gap: 20px;
  list-style: none;
  flex-wrap: wrap;
  padding-left: 0;
}
.nav-links a {
  color: white;
  text-decoration: none;
  font-size: 15px;
}

/* HERO */
.hero {
  background: url('../images/background.jpg') center/cover no-repeat;
  padding: 50px 20px;
  text-align: left;
}
.hero-card {
  background: rgba(255,255,255,0.9);
  padding: 20px;
  border-radius: 10px;
  max-width: 420px;
}

/* LAYOUT */
.content {
  display: flex;
  padding: 25px;
  gap: 25px;
  flex-wrap: wrap;
}

/* LEFT PANEL */
.category-box {
  width: 260px;
  background: white;
  padding: 18px;
  border-radius: 10px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}
.left-panel {
  max-height: 70vh;
  overflow-y: auto;
}
.folder-item {
  padding: 10px;
  border-radius: 6px;
  cursor: pointer;
}
.folder-item.active {
  background: #e7f1ff;
  font-weight: bold;
}

/* SEARCH */
.search-box {
  width: 100%;
  padding: 10px;
  margin-bottom: 12px;
  border-radius: 8px;
  border: 1px solid #ccc;
}

/* FILE THUMBNAIL GRID */
.thumb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px,1fr));
  gap: 20px;
  width: 100%;
}

.thumb-card {
  background: white;
  border-radius: 12px;
  padding: 12px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  text-align: center;
}

.thumb-img {
  width: 100%;
  height: 160px;
  background-size: cover;
  background-position: center;
  border-radius: 10px;
  background-color: #e9eef5;
}

.thumb-title {
  margin-top: 12px;
  font-size: 14px;
  font-weight: 600;
  min-height: 40px;
}

.thumb-btn {
  display: inline-block;
  margin-top: 10px;
  background: #0c4da2;
  color: white;
  padding: 8px 15px;
  border-radius: 6px;
  text-decoration: none;
}

/* FOOTER */
footer {
  background: #0c2f54;
  color: white;
  text-align: center;
  padding: 30px;
}
.cols {
  display: flex;
  justify-content: center;
  gap: 60px;
  flex-wrap: wrap;
}
.cols a {
  color: #dce4ef;
  text-decoration: none;
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .content {
    flex-direction: column;
  }
  .category-box {
    width: 100%;
    max-height: none;
  }
  .thumb-img {
    height: 180px;
  }
}