:root {
  --navy: #0f2f57;
  --blue: #004b8d;
  --red: #C8102E;
  --dark: #1f2937;
  --light-bg: #f4f6f8;
  --white: #fff;
  --border: #dde1e6;
}

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

body {
  font-family: Arial, Helvetica, sans-serif;
  background: var(--light-bg);
  color: var(--dark);
  min-height: 100vh;
}

/* ── Search Area ── */
.search-area {
  background: var(--navy);
  padding: 28px 24px;
  position: sticky;
  top: 0;
  z-index: 10;
  box-shadow: 0 2px 8px rgba(0,0,0,.15);
}

.search-inner {
  max-width: 600px;
  margin: 0 auto;
  display: flex;
  background: var(--white);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(0,0,0,.1);
}

.search-inner input {
  flex: 1;
  padding: 14px 18px;
  border: none;
  font-size: 15px;
  font-family: inherit;
  outline: none;
  background: transparent;
}

.search-inner button {
  padding: 14px 20px;
  background: var(--blue);
  color: var(--white);
  border: none;
  cursor: pointer;
  transition: background .2s;
  display: flex;
  align-items: center;
}

.search-inner button:hover {
  background: var(--navy);
}

/* ── Results Area ── */
#resultsArea {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px;
}

/* ── PDF Container ── */
.pdf-container {
  background: var(--white);
  border-radius: 8px;
  box-shadow: 0 1px 6px rgba(0,0,0,.08);
  overflow: hidden;
}

.pdf-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: var(--white);
  border-bottom: 1px solid var(--border);
}

.pdf-course-info {
  font-size: 14px;
  color: var(--dark);
}

.pdf-course-info .code {
  font-weight: 700;
  color: var(--navy);
  margin-right: 8px;
}

.pdf-course-info .name {
  color: #555;
}

.dl-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 6px;
  background: var(--blue);
  color: var(--white);
  text-decoration: none;
  transition: background .2s;
  flex-shrink: 0;
}

.dl-btn:hover {
  background: var(--navy);
}

.pdf-pages {
  background: #e8e8e8;
}

.pdf-pages iframe {
  width: 100%;
  height: 5800px;
  border: none;
  display: block;
}

/* ── Info / Loading ── */
.info-msg {
  text-align: center;
  padding: 60px 20px;
  color: #999;
  font-size: 15px;
}

.info-msg.error { color: var(--red); }

.loading {
  text-align: center;
  padding: 48px;
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--border);
  border-top-color: var(--blue);
  border-radius: 50%;
  animation: spin .7s linear infinite;
  margin: 0 auto 10px;
}

@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 640px) {
  .search-area { padding: 16px; }
  #resultsArea { padding: 12px; }
  .pdf-toolbar { flex-wrap: wrap; gap: 8px; }
}