/* ===== Brand Palette (Updated to Light Ice Blue & Steel) ===== */
:root {
  --bg: #ffffff;
  --panel: #ffffff;
  --muted: #4a4a4a;
  --text: #1f2937;
  --accent: #ee2b2f;
  --link: #ee2b2f;
  --shade: #E3EBF0;  /* Light Ice Blue for cards/hero */
  --border: #B8C5CE; /* Muted Steel Blue for borders */
}

/* ===== Reset & Base ===== */
* { box-sizing: border-box; }
html, body { height: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Manrope', system-ui, -apple-system, sans-serif;
  line-height: 1.6;
}

/* Typography */
h1 {
  font-family: 'Libre Baskerville', Georgia, serif;
  font-weight: 700;
  font-size: 2.5rem;
  color: var(--accent);
  margin-top: 0.5rem;
  margin-bottom: 0.5rem;
  line-height: 1.2;
}
h1 span {
  font-family: 'Manrope', sans-serif;
  font-weight: 400;
  font-size: 2.0rem;
  color: var(--muted);
  margin-left: 10px;
  display: inline;
  vertical-align: middle;
}
h2, h3 {
  font-weight: 600;
  color: var(--accent);
  margin: 0;
}
h4 {
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.5rem;
}

p { font-size: 1.1rem; color: #333; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== Header & Nav ===== */
.site-header {
  position: sticky; 
  top: 0; 
  z-index: 1000;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  display: flex; 
  align-items: center; 
  padding: .75rem 2rem;
}

.logo {
  font-weight: 700;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: .35rem;
}

.site-nav {
  display: flex; 
  gap: 1rem;
  margin-left: 100px; 
}
.site-nav a { color: var(--text); font-weight: 500; }

/* ===== Main Container & Hero ===== */
main {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: .75rem;
  padding: 1rem;
  max-width: 1100px;
  margin: 1rem auto;
}

.hero {
  background: var(--shade);
  border: 1px solid var(--border);
  border-radius: .75rem;
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.instructor-label {
  display: block;
  font-weight: 700;
  font-size: 0.9rem;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 1rem;
}

/* ===== Premium Collapsible Sections ===== */
.section {
  margin-bottom: 1rem;
}

.collapsible-header {
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: 12px;
  background-color: #f4f4f4; 
  border: 1px solid #000000; 
  padding: 12px 18px;
  border-radius: 6px;
  user-select: none;
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

.collapsible-header:hover {
  background-color: #ebf1f5;
  border-color: var(--accent);
}

.collapsible-header i {
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  font-size: 1.3rem;
  color: var(--text);
}

.collapsible-content {
  /* Smooth Height Transition Logic */
  max-height: 2000px; 
  opacity: 1;
  transform: translateY(0) scaleY(1);
  transform-origin: top;
  overflow: hidden;
  padding: 20px 10px;
  transition: 
    max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1), 
    opacity 0.4s cubic-bezier(0.4, 0, 0.2, 1), 
    transform 0.4s cubic-bezier(0.4, 0, 0.2, 1),
    padding 0.5s ease;
}

.section.collapsed .collapsible-header i {
  transform: rotate(-90deg);
}

.section.collapsed .collapsible-content {
  max-height: 0;
  opacity: 0;
  padding-top: 0;
  padding-bottom: 0;
  transform: translateY(-10px) scaleY(0.95);
  pointer-events: none;
}

/* ===== UPDATED: 3-COLUMN GRID LIST ===== */
.flex-column-list {
  display: grid;
  /* Creates 3 equal columns */
  grid-template-columns: repeat(3, 1fr); 
  gap: 2rem;
  list-style-position: outside;
  padding-left: 25px;
  margin: 1.5rem 0;
  list-style-type: decimal;
}

.flex-column-list > li {
  margin-bottom: 0; 
  display: list-item;
}

.flex-column-list > li::marker { 
  font-weight: 800; 
  font-size: 1.2rem; 
  color: var(--accent);
}


/* Sub-list styling */
.flex-column-list ol {
  list-style-type: lower-alpha;
  padding-left: 20px;
  margin-top: 0.5rem;
}

.flex-column-list ol li {
  margin-bottom: 0.3rem;
  color: var(--muted);
}

/* ===== Grid & Cards ===== */
.grid {
  display: grid; 
  gap: 1rem;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}

.card {
  position: relative;
  background: var(--shade);
  border: 1px solid var(--border);
  border-radius: .75rem;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  min-height: 100%;
  overflow: hidden;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.4s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 8px 20px rgba(98, 124, 139, 0.15);
}

.card-icon {
  position: absolute;
  top: 1rem;
  right: 1rem;
  font-size: 3.2rem;
  color: #808080;
  opacity: 0.15;
  pointer-events: none;
  transition: opacity 0.4s ease, transform 0.4s ease;
}

.card:hover .card-icon {
  opacity: 0.3;
  transform: scale(1.1) rotate(5deg);
}

.button-wrapper {
  margin-top: auto;
  padding-top: 1rem;
}

.button {
  display: inline-block;
  padding: 0.6rem 1.2rem;
  background-color: var(--accent);
  color: #fff !important;
  border-radius: 0.5rem;
  font-weight: 600;
  text-align: center;
  transition: background-color 0.3s ease;
}

.button:hover { background-color: #c41e22; text-decoration: none; }

/* Responsive Adjustments */
@media (max-width: 1024px) {
  /* Drop to 2 columns on tablets */
  .flex-column-list { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .site-nav { margin-left: 20px; font-size: 0.9rem; }
  /* Drop to 1 column on mobile */
  .flex-column-list { grid-template-columns: 1fr; padding-right: 0; }
}